JP3136188U - Force detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce manufacturing costs and prevent electrical noise from being mixed.
A power receiving body 400 made of metal and an apparatus housing 900 are short-circuited by a conductive wire W0 and grounded. The substrate 500 having the diaphragm 510 and the substrate 600 having the diaphragm 610 are made of a resin material, and a metal plating layer P (thick line portion) is formed on a part of the surface thereof. Both substrates 500 and 600 are joined via columnar bodies 520 and 620. The plating layer on the lower surface of the diaphragm 610 forms a common electrode Ec, and a capacitive element is formed between the opposing individual electrodes E. This capacitive element is connected to the detection circuit 750 on the lower surface of the detection substrate 700 via the wirings W1 to W3. When an external force acts on the force receiving body 400, each diaphragm is bent. The detection circuit 750 detects the force in the three-axis direction and the moment about the three axes related to the applied external force based on the change in the capacitance value of each capacitive element due to the bending.
[Selection] Figure 19

Description

  The present invention relates to a force detection device, and more particularly to a force detection device suitable for detecting force and moment independently.

  Various types of force detection devices are used to control the operation of robots and industrial machines. Also, a small force detection device is incorporated as a man-machine interface of an input device of an electronic device. In order to reduce the size and reduce the cost, the force detection device used for such an application has a simple structure as much as possible and can independently detect the force relating to each coordinate axis in the three-dimensional space. Is required.

In general, the detection target of the force detection device includes a force component directed in a predetermined coordinate axis direction and a moment component around the predetermined coordinate axis. When the XYZ three-dimensional coordinate system is defined in the three-dimensional space, the detection target is six components including force components Fx, Fy, Fz in the respective coordinate axis directions and moment components Mx, My, Mz around the respective coordinate axes. . Such a force detection device having a function of detecting six components is generally called a “6-axis force sensor”. Conventionally, in order to detect each of these components independently, it has been necessary to use a force detection device having a fairly complicated three-dimensional structure, but the present inventor has a simpler structure. Invented "6-axis force sensor". For example, Patent Documents 1 and 2 below disclose the basic principle of a unique “6-axis force sensor” according to the invention of the present inventor.
JP 2004-325367 A JP 2004-354049 A

  Many force detection devices, including the “6-axis force sensor” described in the above-mentioned patent documents, cause a flexible member to bend based on the applied external force, and this bend. By detecting this aspect, the direction and the magnitude of the applied external force are detected. Such a force detection device is usually configured using a flexible member made of a metal material such as aluminum or stainless steel. For this reason, there exists a problem that manufacturing cost rises.

  Generally, the metal processing with the lowest cost is press processing, but it is not preferable to form the flexible member for the force detection device by metal pressing. This is because when a metal material is subjected to a forming process that applies pressure like pressing, a mechanical stress remains inside, and this residual stress is “detects a force based on the generated deflection”. This is because the original detection function of the force detection device is adversely affected. For this reason, in order to form a metal flexible member, it is necessary to adopt a relatively expensive machining method such as cutting, electric discharge machining, and wire cutting, which is a factor that increases the manufacturing cost of the entire apparatus. It was.

  Further, when a member made of a metal material is used as a constituent element, another problem that an electrical noise component is likely to be mixed into the detection result occurs.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a force detection device that can further reduce the manufacturing cost, and further to provide a force detection device that can prevent electrical noise components from being mixed.

(1) A first aspect of the present invention is a force detector,
A power receiving body that receives the force to be detected;
An upper substrate having an upper columnar body that is formed in a part of “an upper flexible part that is thinner than other parts and at least a part of which is flexible” and extends downward from the center of the upper flexible part; ,
A lower substrate having a lower columnar body that is formed in a part of “a lower flexible part that is thinner than other parts and at least a part of which is flexible” and extends upward from the center of the lower flexible part; ,
A plurality of individual electrodes are formed in the detection region on the upper surface, and a detection substrate made of an insulating material;
A device housing to which the lower substrate is fixed;
A detection circuit that detects a force acting on the force receiving body based on a degree of bending of the lower flexible portion;
Provided,
The upper substrate and the lower substrate are made of a resin material,
The lower end of the upper columnar body and the upper end of the lower columnar body are joined to each other, and the upper substrate is supported above the lower substrate through these two columnar bodies,
The power receiving body is bonded to the upper substrate so as to be positioned above the upper substrate,
The detection substrate is bonded to the lower surface of the lower substrate so that the detection region is located below the lower flexible portion,
The lower flexible portion is formed at a position such that the lower surface position of the lower flexible portion is higher than the lower surface position of the lower substrate, and between the lower surface of the lower flexible portion and the upper surface of each individual electrode. Has a void,
A common electrode made of a metal plating layer is formed on the lower surface of the lower flexible portion,
The detection circuit is configured to detect a force acting on the force receiving body based on capacitance values of a plurality of capacitive elements configured by the individual electrodes and the common electrode.

(2) A second aspect of the present invention is a force detector,
A power receiving body that receives the force to be detected;
An upper substrate on which a “thin flexible portion at least partially flexible with at least a portion being thinner than other portions” is formed;
A lower substrate having a columnar body that is formed in a part of “a lower flexible part that is thinner than other parts and at least a part of which is flexible” and extends upward from the center of the lower flexible part;
A plurality of individual electrodes are formed in the detection region on the upper surface, and a detection substrate made of an insulating material;
A device housing to which the lower substrate is fixed;
A detection circuit that detects a force acting on the force receiving body based on a degree of bending of the lower flexible portion;
Provided,
The upper substrate and the lower substrate are made of a resin material,
The upper end of the columnar body is joined to the lower surface center of the upper flexible portion, and the upper substrate is supported above the lower substrate via the columnar body,
The power receiving body is bonded to the upper substrate so as to be positioned above the upper substrate,
The detection substrate is bonded to the lower surface of the lower substrate so that the detection region is located below the lower flexible portion,
The lower flexible portion is formed at a position such that the lower surface position of the lower flexible portion is higher than the lower surface position of the lower substrate, and between the lower surface of the lower flexible portion and the upper surface of each individual electrode. Has a void,
A common electrode made of a metal plating layer is formed on the lower surface of the lower flexible portion,
The detection circuit is configured to detect a force acting on the force receiving body based on capacitance values of a plurality of capacitive elements configured by the individual electrodes and the common electrode.

(3) According to a third aspect of the present invention, in the force detection device,
A power receiving body that receives the force to be detected;
An upper substrate having a columnar body that is formed in a portion of “an upper flexible portion that is thinner than other portions and at least a portion of which is flexible” and extends downward from the center of the upper flexible portion;
A lower substrate in which a “lower flexible part having a smaller thickness than other parts and at least a part of which is flexible” is formed in part;
A plurality of individual electrodes are formed in the detection region on the upper surface, and a detection substrate made of an insulating material;
A device housing to which the lower substrate is fixed;
A detection circuit that detects a force acting on the force receiving body based on a degree of bending of the lower flexible portion;
Provided,
The upper substrate and the lower substrate are made of a resin material,
The lower end of the columnar body is joined to the center of the upper surface of the lower flexible portion, and the upper substrate is supported above the lower substrate via the columnar body,
The power receiving body is bonded to the upper substrate so as to be positioned above the upper substrate,
The detection substrate is bonded to the lower surface of the lower substrate so that the detection region is located below the lower flexible portion,
The lower flexible portion is formed at a position such that the lower surface position of the lower flexible portion is higher than the lower surface position of the lower substrate, and between the lower surface of the lower flexible portion and the upper surface of each individual electrode. Has a void,
A common electrode made of a metal plating layer is formed on the lower surface of the lower flexible portion,
The detection circuit is configured to detect a force acting on the force receiving body based on capacitance values of a plurality of capacitive elements configured by the individual electrodes and the common electrode.

(4) A fourth aspect of the present invention is a force detector,
A power receiving body that receives the force to be detected;
An upper substrate on which a “thin flexible portion at least partially flexible with at least a portion being thinner than other portions” is formed;
A lower substrate in which a “lower flexible part having a smaller thickness than other parts and at least a part of which is flexible” is formed in part;
A columnar body having an upper end bonded to the center of the lower surface of the upper flexible portion and a lower end bonded to the center of the upper surface of the lower flexible portion;
A plurality of individual electrodes are formed in the detection region on the upper surface, and a detection substrate made of an insulating material;
A device housing to which the lower substrate is fixed;
A detection circuit that detects a force acting on the force receiving body based on a degree of bending of the lower flexible portion;
Provided,
The upper substrate and the lower substrate are made of a resin material,
The upper substrate is supported above the lower substrate via the columnar body,
The power receiving body is bonded to the upper substrate so as to be positioned above the upper substrate,
The detection substrate is bonded to the lower surface of the lower substrate so that the detection region is located below the lower flexible portion,
The lower flexible portion is formed at a position such that the lower surface position of the lower flexible portion is higher than the lower surface position of the lower substrate, and between the lower surface of the lower flexible portion and the upper surface of each individual electrode. Has a void,
A common electrode made of a metal plating layer is formed on the lower surface of the lower flexible portion,
The detection circuit is configured to detect a force acting on the force receiving body based on capacitance values of a plurality of capacitive elements configured by the individual electrodes and the common electrode.

(5) A fifth aspect of the present invention is the force detection device according to the first to fourth aspects described above,
A metal plating layer is also formed on the upper surface of the lower flexible portion.

(6) A sixth aspect of the present invention is the force detection device according to the fifth aspect described above,
A metal plating layer is formed on both upper and lower surfaces of the upper flexible portion.

(7) A seventh aspect of the present invention is the force detection apparatus according to the sixth aspect described above,
A metal plating layer is formed on almost the entire surface of the upper substrate and the lower substrate.

(8) An eighth aspect of the present invention is the force detection device according to the seventh aspect described above,
A plating notch in which a plating layer is not formed is provided at a connection portion between the upper substrate and the lower substrate, and the plating layer formed on the surface of the upper substrate and the plating layer formed on the surface of the lower substrate are electrically It is designed to be insulated.

(9) A ninth aspect of the present invention is the force detection device according to the first to eighth aspects described above,
The power receiving body is made of a metal material.

(10) A tenth aspect of the present invention is the force detection device according to the ninth aspect described above,
The apparatus casing is made of a metal material, and a conductive wire that electrically short-circuits between the force receiving body and the apparatus casing is provided.

(11) An eleventh aspect of the present invention is the force detection device according to the first to tenth aspects described above,
The detection circuit is provided on the lower surface of the detection substrate,
Wiring between each individual electrode formed on the upper surface of the detection substrate and the detection circuit is made through a through hole provided in the detection substrate.

(12) A twelfth aspect of the present invention is the force detection device according to the eleventh aspect described above,
A wiring layer extends from the common electrode formed on the lower surface of the lower flexible portion, and an end of the wiring layer is disposed on the lower surface of the lower substrate,
The detection substrate is joined to the lower surface of the lower substrate by a conductive screw that passes through the through-hole, and the conductive screw passes through the end of the wiring layer, and using this conductive screw, Wiring between the common electrode and the detection circuit is made.

(13) A thirteenth aspect of the present invention is the force detection device according to the first to twelfth aspects described above,
A raised portion is formed in the vicinity of the center of the upper surface of the upper flexible portion, and the columnar body or the lower flexible portion is joined by a screw that passes through the raised portion and the upper flexible portion. is there.

(14) According to a fourteenth aspect of the present invention, in the force detection device according to the first to thirteenth aspects described above,
A plurality of N sets of upper flexible portions are formed on the upper substrate, and a plurality of N sets of lower flexible portions are formed on the lower substrate. And the upper substrate is supported above the lower substrate through a total of N columnar bodies,
A plurality of N detection regions each having a plurality of individual electrodes are provided on the upper surface of the detection substrate, and a common electrode made of a metal plating layer is provided on the lower surface of the plurality of N lower flexible portions. Each formed,
The detection circuit detects a force acting on the force receiving body based on the capacitance value of the capacitive element formed for each of the plurality of N sets of detection regions.

(15) According to a fifteenth aspect of the present invention, in the force detection device according to the first to fourteenth aspects described above,
Both or one of the upper flexible portion and the lower flexible portion is constituted by a diaphragm having overall flexibility because the wall thickness is thinner than other portions of the substrate.

(16) According to a sixteenth aspect of the present invention, in the force detection device according to the first to fourteenth aspects described above,
Either or both of the upper flexible portion and the lower flexible portion are constituted by a displacement plate and a beam portion that supports the displacement plate from the periphery, and at least the beam portion is flexible. .

(17) According to a fifteenth aspect of the present invention, in the force detection device,
A power receiving body that receives the force to be detected;
A substrate on which a “flexible portion having a smaller thickness than other portions and at least a portion of which is flexible” is formed in part;
A device housing to which the substrate is fixed;
A force transmission body for transmitting the force received by the force receiving body to the flexible portion;
A detection circuit for detecting a force acting on the force receiving body based on a bending degree of the flexible portion;
Provided,
The substrate is made of a resin material, and a metal plating layer is formed on the upper and lower surfaces of the flexible portion.

  According to the force detection device of the present invention, a substrate on which a “flexible portion having a thickness smaller than other portions and at least a portion having flexibility” is formed of a resin material. Since the metal plating layer is formed at a necessary portion of the flexible portion, the flexible portion can be formed without using a metal material. Therefore, the manufacturing cost can be reduced, and a structure that prevents the mixing of electrical noise components is also possible.

  Hereinafter, the present invention will be described based on the illustrated embodiment.

<<< §1. Basic concept of prior art embodiment >>
The present invention is conceived for practical application of the force detection device according to the basic invention disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2004-325367) and Patent Document 2 (Japanese Patent Laid-Open No. 2004-354049). It relates to the improved part. Therefore, in this §1, first, as an example of the force detection device according to the basic invention, a basic concept of an embodiment (hereinafter referred to as a prior art embodiment) disclosed in Patent Document 1 described above will be described.

  FIG. 1 is a perspective view (partially a block diagram) showing a configuration of a force detection device according to a prior art embodiment. As shown in the figure, the basic components of the force detection device are a force receiving body 10, a first force transmitting body 11, a second force transmitting body 12, a third force transmitting body 13, and a fourth force transmitting body 14. , Support 20, first sensor 21, second sensor 22, third sensor 23, fourth sensor 24, and detection circuit 30.

  The force receiving body 10 is a component that receives a force to be detected. Here, for convenience of explanation, an origin O is defined at the center position of the force receiving body 10, and an XYZ three-dimensional coordinate system is defined as illustrated. is doing. In the illustrated example, the force receiving body 10 and the support body 20 are configured by plate-like members, but these do not necessarily have to be plate-like, and may have any shape. The components of the force acting on the force receiving body 10 are force components Fx, Fy, Fz in each coordinate axis direction and moment components Mx, My, Mz around each coordinate axis in this coordinate system.

  In the following description, the term “force” is appropriately used when it means a force in a specific coordinate axis direction and when it means a collective force including a moment component. For example, in FIG. 1, the forces Fx, Fy, and Fz mean force components in the coordinate axis directions that are not moments, but the six forces Fx, Fy, Fz, Mx, My, and Mz. In this case, it means a collective force including a force component in each coordinate axis direction and a moment component around each coordinate axis.

  The support body 20 is a component that is disposed below the force receiving body 10 and performs a function of supporting the force receiving body 10. As described above, the power receiving body 10 and the support body 20 do not necessarily have a plate-like form. However, as will be described later, the upper surface parallel to the XY plane in the XYZ three-dimensional coordinate system described above is used to detect the force related to the coordinate axes X, Y, and Z by the first sensor 21 to the fourth sensor 24. It is preferable to use the support body 20 having the above. In practice, it is preferable that both the power receiving body 10 and the support body 20 have a plate shape. Here, for convenience of explanation, an xy plane is defined on the upper surface of the support 20. The xy plane indicated by lowercase letters is a plane parallel to the XY plane indicated by uppercase letters, and the x axis and the X axis are parallel, and the y axis and the Y axis are parallel.

  The first force transmission body 11 to the fourth force transmission body 14 are members that connect the force receiving body 10 and the support body 20, and are structures disposed along the Z axis. Are arranged at predetermined intervals on the xy plane. In the illustrated example, each of these force transmission bodies 11 to 14 is a columnar structure, and the longitudinal direction thereof is arranged in a direction parallel to the Z axis. A structure having a shape may be used. However, in practice, it is preferable to use a columnar structure as illustrated in order to realize a simple structure. In practice, the first force transmission body 11 to the fourth force transmission body 14 are preferably made of the same material and the same size. This is because the detection sensitivity of the first sensor 21 to the fourth sensor 24 can be made the same if these materials and sizes are made the same. If the materials and sizes are different from each other, it becomes difficult to make the sensitivity of each sensor the same, and a device for correcting the sensitivity is required.

  The important point here is that the upper ends of the force transmitting bodies 11 to 14 are connected to the force receiving body 10 via flexible connecting members (not shown in the figure). The lower ends of the force transmission bodies 11 to 14 are connected to the support body 20 via flexible connection members (not shown in the drawing). In short, the first force transmission body 11 to the fourth force transmission body 14 are connected to the force receiving body 10 and the support body 20 with flexibility. Here, flexibility is synonymous with elasticity, and in the state where no force is applied to the force receiving body 10, the force receiving body 10 takes a fixed position with respect to the support 20, but When some force is applied to the force body 10, the flexible connecting member is elastically deformed, and the relative position between the force receiving body 10 and the support body 20 is changed. Of course, when the force acting on the force receiving body 10 disappears, the force receiving body 10 returns to the original fixed position.

  After all, in the example shown in FIG. 1, the upper end portion and the lower end portion of the columnar first force transmission body 11 to the fourth force transmission body 14 are respectively configured by flexible connection members. (Of course, the entirety of the first force transmission body 11 to the fourth force transmission body 14 may be made of a flexible material). And since this connection member produces a certain amount of elastic deformation, the 1st force transmission body 11-the 4th force transmission body 14 can incline with respect to the force receiving body 10 and the support body 20. As shown in FIG. The connecting member can also be expanded and contracted in the vertical direction (Z-axis direction) in the figure, and when the force receiving body 10 is moved in the upward direction (+ Z-axis direction) in the figure, the connecting member is extended and received. The distance between the force body 10 and the support body 20 is widened. Conversely, when the force receiving body 10 is moved in the downward direction (−Z-axis direction) in the figure, the connecting member contracts, and the force receiving body 10 and the support body 20 are separated. The distance will be narrowed. Of course, the degree of such displacement and inclination increases according to the magnitude of the force acting on the force receiving body 10.

  The first sensor 21 to the fourth sensor 24 are force sensors that detect forces applied from the first force transmission body 11 to the fourth force transmission body 14 toward the support body 20, respectively, and will be described later. Thus, each is comprised from several capacitive element. When a force acts on the force receiving body 10, this force is transmitted to the support body 20 via the force transmitting bodies 11 to 14. Each of the sensors 21 to 24 has a function of detecting the force transmitted in this way, and more specifically, by detecting the force generated by the inclination of the force transmission body, as will be described in detail later. , The function of detecting the inclination of the force transmission body, and the entire force transmission body applies a pressing force (downward in the figure-force in the Z-axis direction) or pulling force (upward in the figure + force in the Z-axis direction). ).

  The detection circuit 30 is a component that performs processing for detecting a force or moment applied to the force receiving body 10 based on capacitance values of a plurality of capacitive elements constituting the sensors 21 to 24, and is an XYZ three-dimensional. A signal indicating force components Fx, Fy, Fz in each coordinate axis direction in the coordinate system and a signal indicating moment components Mx, My, Mz around each coordinate axis are output. Actually, detection of force and moment is performed based on the inclination of the force transmission body and the pressing force / pulling force applied to the support. The specific method will be described later.

  Next, the basic operation principle of the force detection device shown in FIG. 1 will be described with reference to the front view of FIG. Here, for convenience of explanation, only operations related to the first force transmission body 11 and the second force transmission body 12 are shown, but related to the third force transmission body 13 and the fourth force transmission body 14. The operation to perform is the same.

  FIG. 2 (a) shows a state where no force is applied to the force detection device, and the force receiving body 10 maintains a fixed position with respect to the support body 20. Of course, even in this state, since the weight of the force receiving body 10 and the like is applied on the support body 20, the support body 20 receives some force from the first force transmission body 11 and the second force transmission body 12. Although the force received in this state is a force in a steady state, even if such a force is detected by the first sensor 21 or the second sensor 22, it is output from the detection circuit 30. The detected force and moment detection values are adjusted to be zero. In other words, the detection circuit 30, when any change occurs with reference to the detection results of the sensors 21 to 24 in such a steady state, causes the force or moment applied to the force receiving body 10. It has the function to detect as.

  Now, let us consider a case where a force + Fx in the positive direction of the X axis is applied to the force receiving member 10 as shown in FIG. 2 (b). This corresponds to a case where a force that pushes the position of the origin O rightward in the figure is applied. In this case, as shown in the figure, the force receiving body 10 slides in the right direction in the figure, and the first force transmitting body 11 and the second force transmitting body 12 are inclined in the right direction in the figure. It will be. Here, the inclination of the first force transmission body 11 at this time is referred to as θ1, and the inclination of the second force transmission body 12 is referred to as θ2. In addition, the angles θ1 and θ2 indicating the degree of inclination in the direction toward the x-axis in a plane parallel to the XZ plane are referred to as “inclination in the X-axis direction”. Similarly, an angle indicating the degree of inclination in the direction toward the y-axis in a plane parallel to the YZ plane is referred to as “degree of inclination in the Y-axis direction”. In the case of the illustrated example, since the two force transmission bodies 11 and 12 are arranged along the x axis, the inclination in the Y axis direction is zero.

  In addition, if each force transmission body 11 and 12 inclines, since the distance of the power receiving body 10 and the support body 20 will shrink a little, strictly speaking, the power receiving body 10 will be completely translated in the X-axis direction. However, if the inclination is relatively small, the amount of movement in the -Z-axis direction can be ignored. For convenience, it is assumed that the force receiving body 10 has moved only in the X-axis direction.

  On the other hand, let us consider a case where a moment + My around the Y-axis acts on the force receiving member 10 as shown in FIG. In FIG. 2 (c), since the Y axis is a vertical axis toward the back side of the page, in the figure, the moment + My rotates the entire force receiving member 10 in the clockwise direction around the origin O. It corresponds to such a force. Here, the rotation direction of the right screw when the right screw is advanced in the positive direction of the predetermined coordinate axis is defined as a positive moment around the coordinate axis. In this case, as shown in the figure, a reduction force acts on the first force transmission body 11 and an extension force acts on the second force transmission body 12. As a result, a pressing force (a force in the −Z-axis direction: here, referred to as a force −fz) acts on the support body 20 from the first force transmission body 11, and the second force transmission. A tensile force (+ Z-axis direction force: here, referred to as force + fz) acts on the support body 20 from the body 12.

  As described above, in the illustrated force detection device, the two force transmission bodies 11 and 12 are generated when the force Fx in the X-axis direction acts on the force receiving body 10 and when the moment My around the Y-axis acts. The mode of the force transmitted to the support body 20 via this will be different. Therefore, both can be distinguished and detected separately.

  That is, when the force Fx in the X-axis direction is applied, as shown in FIG. 2 (b), the two force transmission bodies 11 and 12 are inclined in the X-axis direction to generate the inclinations θ1 and θ2. Thus, a force corresponding to such an inclination is transmitted to the support 20. Here, the first force transmission body 11 and the second force transmission body 12 and the flexible connection members for connecting them to the support body 20 are made of the same material and the same size. If this force detection device is configured to be bilaterally symmetric with respect to the Z axis in the figure, the inclination θ1 = θ2. Therefore, the sum (θ1 + θ2) of both is a value indicating the force Fx in the X-axis direction. If the inclination θ is handled with a sign (for example, if the inclination in the X-axis positive direction is treated as positive and the inclination in the X-axis negative direction is treated as negative), the applied force X in the X-axis direction Fx Can be detected including the sign.

  However, in this force detection device, as described later, the inclinations of the first force transmission body 11 and the second force transmission body 12 are applied to the support body 20 by the first sensor 21 and the second sensor 22. It will be detected as an applied force. In order to perform such detection, the force applied from each force transmission body to the support 20 may be detected for each individual portion. For example, in FIG. 2B, when considering the stress generated in the connection portion between the first force transmission body 11 and the support body 20, the right side portion and the left side portion of the bottom portion of the first force transmission body 11 are It can be seen that the direction of the generated stress is different. That is, in the illustrated example, since the first force transmission body 11 is inclined to the right side, a pressing force is generated on the right side portion of the bottom portion of the first force transmission body 11, and the upper surface of the support body 20 is directed downward. While a pressing force is generated, a pulling force is generated on the left side portion, and a force that pulls the upper surface of the support 20 upward is generated. Thus, by detecting the difference in stress between the left and right portions of the bottom of the first force transmission body 11, the inclination of the first force transmission body 11 can be obtained. The specific method will be described in detail in §2.

  In the end, in order to detect the force Fx in the X-axis direction by this force detection device, the first sensor 21 detects the tilt state of the first force transmission body 11 in the x-axis direction with respect to the support body 20. It is sufficient that the second sensor 22 has a function of detecting the tilt state of the second force transmission body 12 in the x-axis direction with respect to the support body 20. The first sensor 21 has a function of detecting the degree of inclination θ1 in the X-axis direction of the first force transmission body 11, and the second sensor 22 is inclined in the X-axis direction of the second force transmission body 12. If it has a function of detecting the degree, the detection circuit 30 has the inclination degree θ1 related to the X-axis direction detected by the first sensor 21 and the inclination degree related to the X-axis direction detected by the second sensor 22. Based on the sum of [theta] 2, the process of detecting the X-axis direction component Fx of the force acting on the force receiving body 10 can be performed.

  On the other hand, when the moment My around the Y-axis acts, as shown in FIG. 2 (c), the pressing force −fz and the pulling force + fz from the two force transmission bodies 11 and 12 to the support body 20 Is transmitted. The force transmitted in this way is different from the force when the force transmission body is inclined. That is, as shown in FIG. 2 (b), when the force transmission body is inclined, the stress generated at the bottom of the force transmission body is different between the right side portion and the left side portion. However, when the moment My is applied as shown in FIG. 2 (c), the pressing force -fz is applied by the entire first force transmission body 11, and the tensile force + fz is applied by the entire second force transmission body 12. Will be.

  Thus, with respect to the action of the force Fx in the X-axis direction, the first force transmission body 11 and the second force transmission body 12 are inclined in the same direction as shown in FIG. While an equivalent event occurs, with respect to the action of the moment My around the Y axis, as shown in FIG. 2 (c), with respect to the first force transmission body 11 and the second force transmission body 12, One contradictory event occurs in which one applies a pressing force -fz and the other provides a pulling force + fz. Therefore, the applied moment My can be obtained as a difference between the pulling force + fz and the pressing force −fz, that is, (+ fz) − (− fz) = 2fz.

  In short, in order to detect the moment My around the Y axis by this force detection device, the first sensor 21 has a function of detecting the force applied to the support 20 from the entire first force transmission body 11. Therefore, the second sensor 22 may have a function of detecting a force applied to the support 20 from the entire second force transmission body 12. The first sensor 21 has a function of detecting a force in the Z-axis direction applied to the support body 20 from the entire first force transmission body 11, and the second sensor 22 is a second force transmission body. 12 has a function of detecting the force in the Z-axis direction applied to the support 20 from the entire body 12, the detection circuit 30 can detect the force in the Z-axis direction detected by the first sensor 21 and the second Based on the difference between the force in the Z-axis direction detected by the sensor 22, a process for detecting the moment My around the Y-axis of the force acting on the force receiving body 10 can be performed.

  As described above, only the operations related to the first force transmission body 11 and the second force transmission body 12 have been described with reference to FIG. 2, but the third force transmission body 13 and the fourth force transmission body 14 The related operation is the same, and the detection function of the third sensor 23 and the fourth sensor 24 is used to detect the force Fx in the X-axis direction and the moment My around the Y-axis acting on the force receiving body 10. It is also possible. Further, if the force detection device shown in FIG. 1 is rotated by 90 ° about the Z axis as a rotation axis, and the operation related to the first force transmission body 11 and the fourth force transmission body 14 is considered, It will be understood that the detection function of the sensor 21 and the fourth sensor 24 can be used to detect the force Fy in the Y-axis direction and the moment Mx around the X-axis that acted on the force receiving member 10. Similarly, the operation related to the second force transmission body 12 and the third force transmission body 13 is applied to the force receiving body 10 using the detection function of the second sensor 22 and the third sensor 23. It becomes possible to detect the force Fy in the Y-axis direction and the moment Mx around the X-axis.

<<< §2. 1st sensor to 4th sensor >>>
The force detection device shown in FIG. 1 is provided with a first sensor 21 to a fourth sensor 24. These sensors are force sensors that detect the force applied to the support 20 from the first force transmission body 11 to the fourth force transmission body 14, respectively, but based on the principle described in FIG. In order to detect the forces Fx, Fy, and moments Mx, My, the force generated by the inclination of each force transmitting body 11-14 and the tensile force / pressing force applied by each of the force transmitting bodies 11-14 as a whole A function to detect each independently is required.

  As each of the sensors 21 to 24 having such a function, it is preferable to use a capacitive force sensor having a plurality of capacitive elements. FIG. 3 is a side sectional view showing the basic structure of such a capacitive element type multi-axis force sensor. The multi-axis force sensor itself is a known sensor and has been put into practical use in various fields. Here, for convenience, the basic structure and operation of the multi-axis force sensor will be briefly described.

  As shown in the side sectional view of FIG. 3, this multi-axis force sensor is provided on the upper surface of the plate-like support body 40, the hook-like connection member 50 disposed thereon, the force transmission body 60, and the support body 40. It is comprised by the fixed individual electrode E1-E5. As shown in the top view of FIG. 4, the hook-shaped connecting member 50 has a shape in which a circular flat-bottomed hook is turned down. Here, for convenience of explanation, an xyz three-dimensional coordinate system is defined in which the origin O is at the center of the upper surface of the support 40 and the x, y, and z axes are defined in the illustrated direction. As shown in the side sectional view of FIG. 3, the hook-shaped connecting member 50 includes a disk-shaped diaphragm 51 corresponding to the flat bottom portion of the hook, a cylindrical side wall portion 52 that supports the periphery thereof, and the side wall. The portion 52 includes a fixing portion 53 for fixing the portion 52 to the upper surface of the support body 40, and a cylindrical force transmission body 60 is connected to the center portion of the upper surface of the diaphragm 51. The origin O is defined at the intersection point between the extension of the axis of the cylindrical force transmission body 60 and the upper surface of the support 40.

  Here, in this example, the support body 40 and the force transmission body 60 have sufficient rigidity, but the hook-shaped connection member 50 has flexibility (in other words, a property that causes elastic deformation). ing. Here, for convenience of explanation, it is assumed that the hook-shaped connection member 50 is made of a thin metal plate, and the support body 40 and the force transmission body 60 are made of an insulating material.

  As shown in the top view of FIG. 5, five individual electrodes E <b> 1 to E <b> 5 are formed on the top surface of the plate-like support body 40. Here, the individual electrode E1 is arranged in the positive part of the x axis, the individual electrode E2 is arranged in the negative part of the x axis, the individual electrode E3 is arranged in the positive part of the y axis, and the individual electrode E4 is y They are arranged in the negative part of the axis, and all are electrodes having the same shape and the same size in the shape of a fan that is line-symmetric with respect to each coordinate axis. On the other hand, the individual electrode E5 is a circular electrode arranged at the position of the origin O. The broken lines in FIG. 5 indicate the position of each part of the hook-shaped connection member 50 fixed on the support body 40. As illustrated, the diaphragm 51 is disposed above the support 40 so as to face all of the individual electrodes E1 to E5. As described above, if the diaphragm 51 is made of a conductive material such as a metal plate, the diaphragm 51 has flexibility and conductivity, and the diaphragm 51 itself functions as a single displaceable common electrode. Thus, a capacitive element is formed between each of the opposing individual electrodes E1 to E5. Here, five sets of capacitive elements constituted by the individual electrodes E1 to E5 and the diaphragm 51 functioning as a common electrode will be referred to as capacitive elements C1 to C5, respectively.

  Subsequently, when forces having various directional components are applied to the force transmission body 60, how the hook-like connection member 50 is deformed and what changes are made to the capacitance values of the capacitive elements C1 to C5. Think about what happens.

  First, as shown in FIG. 6, consider a case where a force + fx in the positive x-axis direction is applied to the upper portion of the force transmission body 60. In this case, a force that tilts the force transmission body 60 to the right side acts, and the flexible hook-shaped connection member 50 is deformed as shown in the figure, and the diaphragm 51 has the right side portion downward, The left part is inclined so as to move upward. As a result, the distance between both electrodes (individual electrode E1 and diaphragm 51) of capacitive element C1 is reduced and the capacitance value increases, but the distance between both electrodes (individual electrode E2 and diaphragm 51) of capacitive element C2 is increased. The capacitance value decreases. At this time, for the other three sets of capacitive elements C3 to C5, the distance between the electrodes is reduced in the right half, but the distance between the electrodes is increased in the left half, so that the total capacitance value does not change.

  Such deformation is the same when a force + fx ′ in the positive x-axis direction is applied to the lower portion of the force transmission body 60. However, even if the size of + fx and the size of + fx ′ are equal due to the principle of leverage, the former causes a larger deformation.

  On the other hand, as shown in FIG. 7, a case where a force −fx in the negative x-axis direction is applied to the upper portion of the force transmission body 60 will be considered. In this case, a force for inclining the force transmission body 60 to the left side acts, and the flexible hook-shaped connection member 50 is deformed as shown in the figure. The right part is inclined so as to move upward. As a result, the capacitance value of the capacitive element C1 decreases and the capacitance value of the capacitive element C2 increases.

  Eventually, the force fx in the x-axis direction applied to the force transmission body 60 can be obtained as a difference between the capacitance value of the first capacitance element C1 and the capacitance value of the second capacitance element C2. . The magnitude of the obtained difference indicates the magnitude of the applied force, and the sign of the obtained difference indicates the direction of the applied force. Based on the same principle, the force fy in the y-axis direction applied to the force transmission body 60 is the difference between the capacitance value of the third capacitance element C3 and the capacitance value of the fourth capacitance element C4. Can be sought.

  By the way, the force fx obtained in this way indicates the inclination of the columnar force transmission body 60 in the x-axis direction, and the force fy indicates the inclination of the columnar force transmission body 60 in the y-axis direction. Don't be. Eventually, the inclination of the force transmission body 60 in the x-axis direction can be obtained as a difference between the capacitance value of the first capacitance element C1 and the capacitance value of the second capacitance element C2, and the force transmission body The inclination of 60 in the y-axis direction can be obtained as a difference between the capacitance value of the third capacitance element C3 and the capacitance value of the fourth capacitance element C4. In other words, based on the difference between the force applied from the first portion at the lower end of the force transmitting body 60 and the force applied from the second portion at the lower end of the force transmitting body 60, the support of the force transmitting body 60 is supported. The inclination with respect to the body 40 can be detected.

  Subsequently, as shown in FIG. 8, a case where a force −fz in the negative z-axis direction is applied to the force transmission body 60 will be considered. In this case, since a downward force in the figure is applied to the entire force transmission body 60, the force transmission body 60 is not inclined and is applied to the bowl-shaped connection member 50 by the entire force transmission body 60. As a result, the flexible hook-shaped connecting member 50 is deformed as shown in the figure, and the interval between all the electrodes of the five capacitive elements C1 to C5 is reduced. The capacitance value increases. On the other hand, when a force + fz for pulling up the force transmission body 60 is applied, the force transmission body 60 as a whole exerts an upward pulling force on the hook-like connection member 50, and 5 sets All electrode intervals of the capacitive elements C1 to C5 are widened, and the capacitance value is reduced.

  Eventually, in an environment where only the force fz in the z-axis direction is acting on the force transmission body 60, if any one of the capacitance values of the first to fifth capacitive elements C1 to C5 is detected, the effect is obtained. The applied force fz can be obtained. However, in an environment where forces fx and fy of other axial components are mixed, for example, the capacitance value of the capacitive element C1 is obtained alone, or the capacitance value of the capacitive element C3 is obtained alone. However, these are not necessarily values indicating the force fz in the z-axis direction. In any environment, in order to detect the force fz in the z-axis direction, the capacitance value of the capacitive element C5 may be used. As described above, when the force fx in the x-axis direction or the force fy in the y-axis direction is applied, the capacitance value of the capacitive element C5 does not change, so the capacitance value of the capacitive element C5 is used. Then, only the force fz in the z-axis direction can be detected independently.

  However, in order to detect only the force fz in the z-axis direction independently, another method can be used. For example, the sum of the capacitance value of the capacitive element C1 and the capacitance value of the capacitive element C2 can be obtained and used as a detected value of the force fz in the z-axis direction. For the action of the force fx in the x-axis direction, the increase / decrease in the capacitance value of the capacitive element C1 and the increase / decrease in the capacitance value of the capacitive element C2 have a complementary relationship. The component of the force fx in the x-axis direction can be canceled out, and only the detected value of the force fz in the z-axis direction can be taken out. Similarly, the sum of the capacitance value of the capacitive element C3 and the capacitance value of the capacitive element C4 can be obtained and used as a detected value of the force fz in the z-axis direction. Further, the sum of the capacitance values of the four sets of capacitance elements C1 to C4 and the sum of the capacitance values of the five sets of capacitance elements C1 to C5 are obtained and used as a detection value of the force fz in the z-axis direction. It is also possible to do. Therefore, in principle, the individual electrode E5 (capacitance element C5) is not necessarily provided.

  As described above, when the multi-axis force sensor shown in FIG. 3 is used, the inclination of the force transmission body 60 in the x-axis direction (force fx) and the inclination of the force transmission body 60 in the y-axis direction (force fy) The force (force fz) applied to the support body 40 from the entire force transmission body 60 can be detected. This means that the multi-axis force sensor shown in FIG. 3 can be used as each of the sensors 21 to 24 in the force detection device shown in FIG.

<<< §3. Structure and principle of prior art embodiment >>
Subsequently, the main structural part of the force detection device according to the prior art embodiment will be described with reference to FIGS. 9 to 13, the operation principle of this device will be described with reference to FIGS. 14 and 15, and another prior art will be described. The main structural part of the force detection device according to the technical embodiment will be described with reference to FIG.

  FIG. 9 is a top view of the force detection device according to this prior art embodiment. A side cross-sectional view along the cutting line 10-10 in this top view is shown in FIG. 10, and a side cross-sectional view along the cutting line 11-11 is shown in FIG. As shown in FIG. 10 or FIG. 11, the basic components of this force detection device are an upper substrate 100, a lower substrate 200, and a support substrate 300, all of which are plate-like members having a square upper surface. Is the basic form. 10 and 11 are side cross-sectional views at different cutting positions, and the geometric structures appearing in the drawings are exactly the same. The difference between them is only the sign of each part.

  As shown in FIG. 9, the upper substrate 100 is basically a plate-like member having a square upper surface, but the four cylindrical protrusions 110, 120, 130, and 140 are directed downward from the lower surface. It is growing. Here, these cylindrical projections are referred to as upper columnar bodies 110, 120, 130, and 140. FIG. 12 is a cross-sectional view showing a state in which the upper substrate 100 is cut along the XY plane. Here, for convenience of explanation, an origin O is defined at the center of the upper substrate 100 as shown in the figure, and the X axis is in the right direction in the figure, the Y axis is in the upward direction, and the Z axis is in the upward direction perpendicular to the paper surface. Therefore, an XYZ three-dimensional coordinate system will be defined. The upper substrate 100, the lower substrate 200, and the support substrate 300 made of a plate-like member having a square upper surface are all parallel to the XY plane, and each side is on the X axis or the Y axis. They are arranged in parallel.

  As shown in FIG. 12, annular grooves G11, G12, G13, and G14 are formed around the bases of the four upper columnar bodies 110, 120, 130, and 140, and the grooves G11. , G12, G13, and G14, the plate-like upper substrate 100 has an upper diaphragm 115, 125, 135, which is made of a thin portion having flexibility, as shown in FIGS. 145 is formed. Eventually, the four upper columnar bodies 110, 120, 130, and 140 are connected to the plate-like upper substrate 100 via the upper diaphragms 115, 125, 135, and 145. Here, the arrangement of each upper columnar body will be described in more detail. “A square that is arranged at a position centered on the origin and is smaller than the outline of the upper substrate 100 and whose vertical and horizontal directions are parallel to the X and Y axes”. The upper columnar bodies 110, 120, 130, and 140 are arranged so that the positions of the central axes are respectively positioned at the four vertexes.

  On the other hand, as shown in FIG. 13, the support substrate 300 is a complete plate-like member having a square upper surface, and the individual electrodes E11 to E15, E21 to E25, E31 to E35, E41 to E45 are formed on the upper surface. Is arranged. The lower substrate 200 bonded to the upper surface of the support substrate 300 is basically a plate-like member having a square upper surface. However, as shown in FIGS. Lower columnar bodies 210, 220, 230, and 240 extend upward. Annular grooves G21, G22, G23, and G24 are formed around the base portions of these four lower columnar bodies 210, 220, 230, and 240. Further, on the lower surface of the lower substrate 200, Cylindrical grooves G31, G32, G33, and G34 are formed. The groove portions G21, G22, G23, and G24 provided on the upper surface of the lower substrate 200 and the groove portions G31, G32, G33, and G34 provided on the lower surface are all center axes of the lower columnar bodies 210, 220, 230, and 240. It has a circular outline of the same size around the position of. As shown in FIG. 10, a lower diaphragm 215 exists as a boundary wall between the groove portions G21 and G31, and a lower diaphragm 225 exists as a boundary wall between the groove portions G22 and G32. Further, as shown in FIG. 11, a lower diaphragm 235 exists as a boundary wall between the grooves G23 and G33, and a lower diaphragm 245 exists as a boundary wall between the grooves G24 and G34.

  The lower surfaces of the four upper columnar bodies 110, 120, 130, 140 extending downward from the upper substrate 100 side are the upper surfaces of the four lower columnar bodies 210, 220, 230, 240 extending upward from the lower substrate 200 side. Are joined. Here, as shown in FIG. 10, a columnar structure formed by joining the upper columnar body 110 and the lower columnar body 210 is called a first force transmission body T1, and the upper columnar body 120 and the lower columnar body A columnar structure formed by joining the columnar body 220 will be referred to as a second force transmission body T2. Further, as shown in FIG. 11, a columnar structure formed by joining the upper columnar body 130 and the lower columnar body 230 is called a third force transmission body T3, and the upper columnar body 140 and the lower columnar body A columnar structure formed by joining the body 240 is referred to as a fourth force transmission body T4. As can be seen from the top view of FIG. 9, when the arrangement of the four force transmission bodies T1 to T4 in the XY two-dimensional coordinate system is considered, the first force transmission body T1 has a second force The transmission body T2 is disposed in the second quadrant, the third force transmission body T3 is disposed in the third quadrant, and the fourth force transmission body T4 is disposed in the fourth quadrant, both of which are parallel to the Z axis. It is a columnar structure which is the longitudinal direction.

  Further, as shown in FIG. 10, the upper end of the first force transmission body T1 is connected to the upper substrate 100 with the upper diaphragm 115 having flexibility as a connecting member, and the upper end of the second force transmission body T2 Is connected to the upper substrate 100 with the upper diaphragm 125 having flexibility as a connecting member. As shown in FIG. 11, the upper end of the third force transmitting body T3 is connected to the upper diaphragm 135 having flexibility. Is connected to the upper substrate 100 as a connecting member, and the upper end of the fourth force transmission body T4 is connected to the upper substrate 100 using the upper diaphragm 145 having flexibility as a connecting member.

  On the other hand, as shown in FIG. 10, the lower surface of the first force transmission body T <b> 1 is joined to the center of the lower diaphragm 215 that functions as a connecting member, and the periphery of the lower diaphragm 215 is supported via the lower substrate 200. 300, the lower surface of the second force transmission body T2 is joined to the center of the lower diaphragm 225 functioning as a connecting member, and the periphery of the lower diaphragm 225 is supported by the support substrate 300 via the lower substrate 200. It is connected to the. Similarly, as shown in FIG. 11, the lower surface of the third force transmission body T3 is joined to the center of the lower diaphragm 235 that functions as a connecting member, and the periphery of the lower diaphragm 235 is supported via the lower substrate 200. Connected to the substrate 300, the lower surface of the fourth force transmission body T4 is joined to the center of the lower diaphragm 245 functioning as a connecting member, and the periphery of the lower diaphragm 245 is supported via the lower substrate 200. 300.

  In the illustrated prior art embodiment, the upper substrate 100 and the lower substrate 200 are made of metal such as stainless steel, aluminum, titanium, and the support substrate 300 is, for example, a PCB substrate (Print Circuit Board: made of glass epoxy). An insulating substrate such as a printed circuit board for circuit mounting). The upper diaphragms 115, 125, 135, 145 and the lower diaphragms 215, 225, 235, 245 are parts configured to have flexibility by making the thickness thinner than other parts of the substrate.

  Thus, since the lower diaphragms 215, 225, 235, and 245 are made of metal, they have flexibility and conductivity, and themselves function as a common electrode. This is exactly the same as the configuration of the multi-axis force sensor shown in FIG. That is, the individual electrodes E11 to E15 shown in the first quadrant in the xy two-dimensional coordinate system defined on the upper surface of the support substrate 300 shown in FIG. 13, the individual electrodes E21 to E25 shown in the second quadrant, The individual electrodes E31 to E35 shown in the third quadrant and the individual electrodes E41 to E45 shown in the fourth quadrant are all equivalent components to the individual electrodes E1 to E5 shown in FIG. The lower diaphragms 215 and 225 shown in FIG. 10 and the lower diaphragms 235 and 245 shown in FIG. 11 are all equivalent components to the diaphragm 51 shown in FIG. Therefore, sensors S1 and S2 having functions equivalent to those of the multiaxial force sensor shown in FIG. 3 are formed around the groove G31 and the groove G32 shown in FIG. Sensors S3 and S4 having functions equivalent to those of the multiaxial force sensor shown in FIG. 3 are also formed around the groove G33 and the groove G34.

  Here, the sensor S1 includes the inclination of the first force transmission body T1 in the X-axis direction, the inclination in the Y-axis direction, and the Z-axis applied to the support substrate 300 from the entire first force transmission body T1. The sensor S2 has a function of detecting the force related to the direction, and the sensor S2 includes the inclination of the second force transmission body T2 in the X-axis direction, the inclination in the Y-axis direction, and the second force transmission body T2. It has a function of detecting the force in the Z-axis direction applied to the support substrate 300 from the whole. Similarly, the sensor S3 includes the inclination of the third force transmission body T3 in the X-axis direction, the inclination in the Y-axis direction, and the Z-axis applied to the support substrate 300 from the entire third force transmission body T3. The sensor S4 has a function of detecting a force related to the direction, and the sensor S4 has a degree of inclination of the fourth force transmission body T4 in the X-axis direction, a degree of inclination in the Y-axis direction, and a fourth force transmission body T4. It has a function of detecting the force in the Z-axis direction applied to the support substrate 300 from the whole.

  In this way, it can be seen that the force detection device according to the prior art embodiment shown in FIGS. 9 to 13 is provided with almost the same components as the force detection device shown in FIG. That is, the plate-like upper substrate 100 corresponds to the force receiving body 10, the plate-like support substrate 300 corresponds to the support body 20, the force transmission bodies T1 to T4 correspond to the force transmission bodies 11 to 14, Each sensor S1-S4 corresponds to each sensor 21-24. Therefore, if a wiring and a circuit functioning as the detection circuit 30 are added to the structures shown in FIGS. 9 to 13, the force detection device shown in FIG. 1 can be realized.

  Subsequently, by the force detection device according to this prior art embodiment, the force Fx in the X-axis direction, the force Fy in the Y-axis direction, the force Fz in the Z-axis direction, and the moments Mx, Y about the X-axis applied to the upper substrate 100 The principle of independently detecting six components of the force, the moment My around the axis and the moment Mz around the Z axis, will be described.

  Now, it is constituted by 20 individual electrodes E11 to E15, E21 to E25, E31 to E35, E41 to E45 shown in FIG. 13 and respective common electrodes (lower diaphragms 215, 225, 235, 245) opposed thereto. These 20 sets of capacitive elements are referred to as C11 to C15, C21 to C25, C31 to C35, and C41 to C45, respectively. C11 to C45 shown in parentheses in FIG. 13 indicate individual capacitive elements constituted by the individual electrodes. Also, the origin O is set at a predetermined position in the upper substrate 100 shown in FIG. 12, and an XYZ three-dimensional coordinate system is defined as shown. Then, with respect to the upper substrate 100, the X-axis positive force + Fx, the Y-axis positive force + Fy, the Z-axis positive force + Fz, the positive moment about the X axis + Mx, the positive direction about the Y-axis Consider the change in the capacitance value of each of the 20 capacitive elements C11 to C45 when the positive moment + My and the positive moment + Mz around the Z-axis act.

  FIG. 14 is a table showing how the capacitance values of the capacitive elements C11 to C45 change at this time. “0” indicates no change, “+” indicates an increase, and “−” indicates a decrease. . The reason why the capacitance value of each capacitive element changes as shown in this table is that if the change mode of each force transmission body shown in FIG. 2 and the deformation mode of the multi-axis force sensor shown in FIGS. I understand.

  For example, when a force + Fx in the positive direction of the X-axis acts on the upper substrate 100, as shown in FIG. Since it tilts in the right direction (X-axis positive direction), referring to the plan view of FIG. On the other hand, it can be seen that the electrode intervals of the capacitive elements C12, C22, C32, C42 are widened and the capacitance value is decreased. For other capacitive elements, the electrode spacing is partially expanded and partially decreased, so that the capacitance value does not change in total. The first row (+ Fx row) of the table of FIG. 14 shows such a change in capacitance value for each of the capacitive elements C11 to C45.

  On the contrary, when the force -Fx in the negative X-axis direction is applied, each of the force transmission bodies T1 to T4 is inclined in the left direction (X-axis negative direction) in FIGS. The relationship between the increase and decrease of the capacitance value is reversed, and the result of reversing “+” and “−” with respect to the first row (+ Fx row) of the table of FIG. 14 is obtained.

  On the other hand, when the force + Fy in the Y-axis positive direction is applied to the upper substrate 100, a phenomenon occurs in which the change mode when the force + Fx is applied is rotated by 90 ° when viewed from the upper surface. That is, referring to the plan view of FIG. 13, the electrode intervals of the capacitive elements C13, C23, C33, and C43 are narrowed and the capacitance value is increased, whereas the electrodes of the capacitive elements C14, C24, C34, and C44 are increased. It can be seen that the interval increases and the capacitance value decreases. For other capacitive elements, the electrode spacing is partially expanded and partially decreased, so that the capacitance value does not change in total. The second row (+ Fy row) of the table of FIG. 14 shows such a change in capacitance value for each of the capacitive elements C11 to C45. On the other hand, when the force -Fx in the Y-axis negative direction is applied, the relationship between the increase and decrease in the capacitance value is reversed, and the result of reversing “+” and “−” is obtained.

  Further, when a force + Fz in the positive direction of the Z-axis acts on the upper substrate 100, each of the force transmission bodies T1 to T4 applies a tensile force to the upper surface of the support substrate 300. The electrode interval of the capacitive elements C11 to C45 is increased, and the capacitance value is decreased. The third row (+ Fz row) in the table of FIG. 14 shows such a change. On the other hand, when the force −Fz in the negative Z-axis direction acts on the upper substrate 100, each of the force transmission bodies T <b> 1 to T <b> 4 applies a pressing force to the upper surface of the support substrate 300. The electrode spacing of all the capacitive elements C11 to C45 is narrowed, and the capacitance value is increased. Accordingly, a result obtained by reversing “+” and “−” with respect to the result shown in the third row (+ Fz row) of the table of FIG. 14 is obtained.

  Next, let us consider a case where a moment acts on the upper substrate 100. FIG. 2C shows how the force transmission bodies 11 and 12 change when a moment My around the Y-axis acts on the upper substrate 10. That is, a downward pressing force −fz is applied from the force transmission body 11 to the support body 20, and an upward pulling force + fz is applied from the force transmission body 12 to the support body 20. Considering that such a change mode occurs, if a positive moment + Mx around the X axis is applied to the upper substrate 100, in the top view of FIG. A force + fz is applied, and a force −fz perpendicular to the plane of the drawing is applied to the point P4.

  Therefore, the first force transmission body T1 and the second force transmission body T2 shown in FIG. 10 are applied with an upward force + fz in the figure, the electrode spacing of the capacitive elements C11 to C25 is widened, and the capacitance value is Decrease. Further, the third force transmission body T3 and the fourth force transmission body T4 shown in FIG. 11 are applied with a downward force -fz in the figure, the electrode spacing of the capacitive elements C31 to C45 is reduced, and the capacitance value Will increase. The fourth row (+ Mx row) of the table of FIG. 14 shows such a change in capacitance value for each of the capacitive elements C11 to C45. Conversely, when a negative moment -Mx around the X axis is applied, the relationship between the increase and decrease of the capacitance value is reversed, and the result of reversing "+" and "-" is obtained.

  On the other hand, when a positive moment + My around the Y-axis acts, in the top view of FIG. 9, a force −fz perpendicular to the plane of the paper acts on the point P1, and vertically upward on the plane of the point P2. The force + fz is applied. Accordingly, the first force transmission body T1 shown in FIG. 10 and the fourth force transmission body T4 shown in FIG. 11 are applied with a downward force -fz in the figure, and the electrodes of the capacitive elements C11 to C15 and C41 to C45. The interval decreases and the capacitance value increases. Further, the second force transmission body T2 shown in FIG. 10 and the third force transmission body T3 shown in FIG. 11 are subjected to an upward force + fz in the figure, and the electrode spacing between the capacitive elements C21 to C25 and C31 to C35. Spreads and the capacitance value decreases. The fifth row (+ My row) of the table of FIG. 14 shows such a change in capacitance value for each of the capacitive elements C11 to C45. Conversely, when a negative moment -My around the Y axis acts, the relationship between the increase and decrease of the capacitance value is reversed, and the result of reversing "+" and "-" is obtained.

  Finally, consider a case where a moment Mz about the Z-axis acts on the upper substrate 100. First, referring to FIG. 13, when a positive moment + Mz around the Z-axis (which is a counterclockwise moment on the plan view of FIG. 13) is applied to the upper substrate 100, four force transmission bodies Let us consider in which direction T1 to T4 are inclined.

  First, the first force transmission body T1 arranged in the first quadrant (arranged on the individual electrode E15 in the figure) is inclined in the upper left direction in FIG. 13, and the capacitive elements C12, C13 The electrode interval is reduced and the capacitance value is increased, and the electrode interval of the capacitive elements C11 and C14 is increased and the capacitance value is decreased. Further, the second force transmission body T2 arranged in the second quadrant (arranged on the individual electrode E25 in the figure) is inclined in the lower left direction in FIG. 13, and the capacitive elements C22, C24. The electrode interval is reduced and the capacitance value is increased, and the electrode intervals of the capacitive elements C21 and C23 are increased and the capacitance value is reduced. Further, the third force transmission body T3 (arranged on the individual electrode E35 in the figure) arranged in the third quadrant is inclined in the lower right direction in FIG. The electrode interval of C34 is reduced and the capacitance value is increased, and the electrode interval of the capacitive elements C32 and C33 is increased and the capacitance value is decreased. Finally, the fourth force transmission body T4 (arranged on the individual electrode E45 in the figure) arranged in the fourth quadrant is inclined in the upper right direction in FIG. The electrode interval of C43 is reduced and the capacitance value is increased, and the electrode interval of the capacitive elements C42 and C44 is increased and the capacitance value is decreased. Note that the capacitance values of the capacitive elements C15, C25, C35, and C45 do not change in total.

  Eventually, when a positive moment + Mz around the Z-axis acts on the upper substrate 100, an increase / decrease result as shown in the sixth row of FIG. 14 is obtained. In addition, when a negative moment -Mz around the Z-axis acts on the upper substrate 100, the relationship between the increase and decrease in the capacitance value is reversed, and the result of reversing "+" and "-" is obtained. It will be.

  Considering that the results shown in the table of FIG. 14 are obtained, as the detection circuit 30, the capacitance values of the 20 sets of capacitive elements C11 to C45 (here, the capacitance values themselves are the same sign). If a circuit that performs an operation based on the expression shown in FIG. 15 is prepared based on (C11 to C45), six components Fx, Fy, Fz, Mx, My, and Mz can be obtained. Can understand.

  For example, the formula Fx = (C11−C12) + (C21−C22) + (C31−C32) + (C41−C42) shown in FIG. 15 is the first row (+ Fx row) of the table of FIG. Based on the result, the X-axis direction of the force acting on the upper substrate 100 based on the sum of the inclinations of the force transmission bodies T1 to T4 detected by the first to fourth sensors in the X-axis direction. This means that the component Fx can be detected. This is based on the detection principle shown in FIG.

  Also, the expression Fy = (C13−C14) + (C23−C24) + (C33−C34) + (C43−C44) shown in FIG. 15 is the second row (+ Fy row) of the table of FIG. Based on the result, the Y-axis direction of the force acting on the upper substrate 100 based on the sum of the inclinations of the force transmission bodies T1 to T4 with respect to the Y-axis direction detected by the first to fourth sensors. This means that the component Fy can be detected. This is also based on the detection principle shown in FIG.

  Further, the formula Fz = − (C15 + C25 + C35 + C45) shown in FIG. 15 is based on the result of the third row (+ Fz row) of the table of FIG. 14 and is detected by the first to fourth sensors. This means that the Z-axis direction component Fz of the force acting on the upper substrate 100 can be detected based on the sum of the forces in the Z-axis direction of the force transmission bodies T1 to T4. The leading minus sign is based on the Z axis direction.

  On the other hand, the equation Mx = − (((C11 + C12 + C13 + C14 + C15) + (C21 + C22 + C23 + C24 + C25)) − ((C31 + C32 + C33 + C34 + C35)) + (C41 + C42 + C43 + C44 + C45)) shown in FIG. The difference between the sum of the forces in the Z-axis direction detected by the first and second sensors and the sum of the forces in the Z-axis direction detected by the third and fourth sensors This means that the moment Mx around the X axis of the force acting on the upper substrate 100 can be detected. In the top view shown in FIG. 9, the point P3 is moved vertically upward (Z-axis positive direction) with respect to the paper surface, and the point P4 is moved vertically downward (Z-axis negative direction) with respect to the paper surface. This is based on the detection principle shown in FIG. The minus sign at the beginning of the formula is due to the way the moment is taken.

  Further, the equation My = ((C11 + C12 + C13 + C14 + C15) + (C41 + C42 + C43 + C44 + C45)) − ((C21 + C22 + C23 + C24 + C25) + (C31 + C32 + C33 + C34 + C35)) shown in FIG. 15 is based on the fifth row of the table in FIG. And based on the difference between the sum of forces in the Z-axis direction detected by the first and fourth sensors and the sum of forces in the Z-axis direction detected by the second and third sensors, This means that the moment My around the Y axis of the force acting on the upper substrate 100 can be detected. In the top view shown in FIG. 9, the point P1 moves vertically downward (Z-axis negative direction) with respect to the paper surface, and the point P2 moves vertically upward (Z-axis positive direction) with respect to the paper surface. This is based on the detection principle shown in FIG.

  Finally, Mz = (((C31-C32) + (C41-C42))-((C11-C12) + (C21-C22))) + (((C13-C14) + (C43-) shown in FIG. C44)) − ((C23−C24) + (C33−C34))) is based on the result of the sixth row (+ Mz row) of the table of FIG. A difference between the sum of the inclinations in the X-axis direction detected by the sensors and the sum of the inclinations in the X-axis direction detected by the first and second sensors is obtained as a first difference, and The difference between the sum of the inclinations in the Y-axis direction detected by the fourth sensor and the sum of the inclinations in the Y-axis direction detected by the second and third sensors is obtained as the second difference, Based on the sum of the difference of 1 and the second difference, the upper substrate 10 Moment Mz about the Z-axis of the applied force is meant that can be detected.

The meaning of this Mz equation is
Mz = (C12 + C13)-(C11 + C14)
+ (C22 + C24)-(C21 + C23)
+ (C31 + C34)-(C32 + C33)
+ (C41 + C43)-(C42 + C44)
If you rewrite it like this, it will be easier to understand. That is, when the positive moment + Mz around the Z-axis acts, as described above, in FIG. 13, the first force transmission body T1 disposed on the individual electrode E15 is inclined in the upper left direction in the figure. Of course, (C12 + C13) − (C11 + C14) in the above expression is a term for detecting such an inclination of the first force transmission body T1. Similarly, the second force transmission body T2 disposed on the individual electrode E25 is inclined in the lower left direction in the figure, but the above formula (C22 + C24) − (C21 + C23) is the second force. This is a term for detecting such an inclination of the transmission body T2. Further, the third force transmission body T3 disposed on the individual electrode E35 is inclined in the lower right direction in the figure, but the above formula (C31 + C34) − (C32 + C33) is the third force. This is a term for detecting such an inclination of the transmission body T3. Further, the fourth force transmission body T4 disposed on the individual electrode E45 is inclined in the upper right direction in the figure, but the above formula (C41 + C43) − (C42 + C44) is the fourth force transmission. This is a term for detecting such a tilt of the body T4. Thus, the above equation shows the sum of the detected values of the inclination in the predetermined direction of the four force transmission bodies T1 to T4 when the moment Mz around the Z axis is applied.

  Note that in the third formula (Fz formula) in FIG. 15, the capacitance value of one capacitive element C15 is the force in the Z-axis direction of the first force transmission body T1 detected by the first sensor. In the fourth equation (Mx equation) in FIG. 15, similarly, the force in the Z-axis direction of the first force transmission body T1 detected by the first sensor is (C11 + C12 + C13 + C14 + C15). The sum of the capacitance values of the five capacitive elements is used. This shows that there are a plurality of variations in the method for obtaining the force in the Z-axis direction using the multi-axis force sensor of the type shown in FIG. 3 as described in §2. Therefore, for example, the third equation in FIG. 15 may be Fz = − ((C11 + C12 + C13 + C14 + C15) + (C21 + C22 + C23 + C24 + C25) + (C31 + C32 + C33 + C34 + C35) + (C41 + C42 + C43 + C44 + C45)). Similarly, the fourth equation of FIG. 15 may be Mx = ((C15 + C25) − (C35 + C45)), or the fifth equation of FIG. 15 may be My = ((C15 + C45) − (C25 + C35)). It doesn't matter. Of course, several other variations are possible.

  Of the six formulas shown in FIG. 15, formulas relating to the forces Fx, Fy, and Fz are general formulas that are established even when the four force transmission bodies T1 to T4 are arranged at arbitrary positions. When configuring a force detection device used only for detecting Fy and Fz, the four force transmission bodies T1 to T4 need not necessarily be arranged as shown in the top view of FIG. However, among the six formulas shown in FIG. 15, the formulas for the moments Mx, My, and Mz are the four force transmission bodies T1 to T4, as shown in the top view of FIG. It is premised on being arranged in the first to fourth quadrants.

  By the way, the technical idea according to this prior art embodiment is completely different from the technique of “increasing detection accuracy by simply using four sets of conventionally known multi-axis force sensors as shown in FIG. 3”. It is a technical idea with different dimensions. In general, when performing measurement using any measuring instrument, the technique of “improving measurement accuracy by installing multiple identical measuring instruments and taking the average of each measurement result” is a conventional method. Have been used in various fields.

  However, the basic concept shown in FIG. 2 is not the technical idea of “increasing detection accuracy using a plurality of sensors”, but “detecting by accurately distinguishing the force in the predetermined coordinate axis direction and the moment around the predetermined coordinate axis. It is in the technical idea of “Yes”. Here is a little more detailed supplementary explanation about this point.

  First, as shown in FIG. 6, let us consider detecting a positive force + fx in the x-axis direction using a conventionally known multi-axis force sensor. In a general publicly known document disclosing such a multi-axis force sensor, according to the principle shown in FIG. The explanation is that the x-axis direction component fx of the force acting on the force transmission body 60 can be obtained by obtaining the difference (C1-C2) between the capacitance value C2 of the electrode E2 and the diaphragm 51). Has been made. However, this explanation is not correct in the strict sense. This is because the difference between the capacitance values (C1-C2) is actually not the applied force fx itself but the moment My around the y-axis caused by the applied force fx.

  This can be easily understood by considering what output values can be obtained when two types of forces + fx and + fx ′ are applied to different positions of the force transmission body 60 as shown in FIG. I can do it. In the example shown in the figure, even if + fx = + fx ′, the output value obtained as the difference in capacitance value (C1−C2) is greater when + fx is added than when + fx ′ is added. Become bigger. This is because a larger moment can be given to this detection system when + fx is added. In short, the sensor shown in FIG. 6 cannot directly detect the force fx in the x-axis direction and the force fy in the y-axis direction, but can only detect them as the moment My around the y-axis and the moment Mx around the x-axis, respectively. There is no.

  However, if the position on the force transmission body 60 to which the force fx is applied is determined so as to be always a fixed position, there is no problem even if the moment My around the y-axis is handled as the force fx in the x-axis direction. Therefore, even if the force sensor shown in FIG. 6 is used for detection of the force fx in the x-axis direction and the force fy in the y-axis direction, it is practical for detection objects that do not need to handle force and moment separately. On top of that, no major hindrance will occur.

  However, in applications such as robot and industrial machine operation control, there is a considerable demand for force detection devices that can detect force and moment clearly. The above-described force detection device can be said to be a device suitable for such an application. For example, if the force detection device shown in FIG. 10 is used as a joint portion between a robot arm and a wrist, the support substrate 300 may be attached to the arm side and the upper substrate 100 may be attached to the wrist side. Then, it is possible to detect the force and moment applied to the wrist side with respect to the arm.

  If a force is applied to the upper substrate 100 using the force detection device shown in FIG. 10, a predetermined change occurs in the positions and orientations of the four force transmission bodies T1 to T4. If this change mode is detected as a change in capacitance values of a plurality of capacitive elements constituting the sensors S1 to S4, and an analysis based on the equation shown in FIG. 15 is performed, the forces Fx, Fy, Fz in the respective axial directions And moments Mx, My, and Mz around each axis can be detected independently. This is an important feature of the present invention.

  As already described in the above description, in the force detection device according to this prior art embodiment, the individual electrodes E11 to E15, E21 to E25, E31 to E35, E41 are formed on the upper surface of the support substrate 300 as shown in FIG. E45 are formed, and lower diaphragms 215, 225, 235, and 245 made of a conductive material disposed above these individual electrodes function as common electrodes, and a total of 20 capacitive elements C11 to C15 (sensor S1) ), C21 to C25 (sensor S2), C31 to C35 (sensor S3), and C41 to C45 (sensor S4). The lower diaphragms 215, 225, 235, and 245 are a part of the lower substrate 200 made of metal, and electrically function as a single equipotential body, so that all the common electrodes maintain an equipotential.

  Here, the lower surfaces of the lower diaphragms 215, 225, 235, and 245 constitute displacement surfaces that generate specific displacements according to the displacements of the lower portions of the force transmission bodies T1 to T4, respectively. Based on the principle shown in the equation, the force acting on the upper substrate 100 can be detected independently for each of the six components.

  As a method for obtaining each force component based on each arithmetic expression shown in FIG. 15, the electrostatic capacitance value of each capacitive element is electrically measured, and an analog or digital arithmetic unit is used for the measured value. It is also possible to take a method of performing the operation and outputting the result. However, the equation shown in FIG. 15 is basically only addition and subtraction. Therefore, in practice, instead of performing the addition of electrostatic capacitance values with an arithmetic unit, an approach in which a plurality of capacitive elements to be subjected to addition of capacitance values are connected in parallel to each other, and results equivalent to the addition operation can be obtained. It is preferable to adopt. In addition, although description of a specific circuit is abbreviate | omitted here, generally the capacitance value of the said capacitive element is converted into a voltage value and detected by providing wiring to a pair of electrode which comprises a capacitive element, respectively. Various circuits are known. If such a circuit is prepared as the detection circuit 30, the forces Fx, Fy, Fz in the respective axial directions and the moments Mx, My, Mz around the respective axes can be output as independent voltage values.

  As described above, the prior art embodiment disclosed in Patent Document 1 described above has been described with reference to FIGS. 9 to 15, but the force detection device to which the present invention is applied is not necessarily the above-described prior art embodiment. It is not limited to. In particular, there are various variations in the number and arrangement of the force transmission members formed between the upper substrate 100 and the lower substrate 200. Patent Document 1 and Patent Document 2 described above include such variations. Various variations are posted. There are also various variations in the shape, number, and arrangement of each individual electrode. The present invention is applicable to these variations as well.

  Further, the present invention is naturally applicable to a force detection device having a structure shown in FIG. 16 instead of the structure shown in FIG. In the apparatus shown in FIG. 10, the upper diaphragms 115 and 125 are formed at positions aligned with the upper surface of the upper substrate 100, and the grooves G <b> 11 and G <b> 12 are formed on the lower surface side of the upper substrate 100. On the other hand, in the apparatus shown in FIG. 16, the upper diaphragms 115A and 125A are formed at positions aligned with the lower surface of the upper substrate 100A, and the grooves G11A and G12A are formed on the upper surface side of the upper substrate 100A. The upper columnar portions 110A and 120A shown in FIG. 16 are slightly shorter than the upper columnar portions 110 and 120 shown in FIG. 10, but are connected to the upper surfaces of the lower columnar portions 210 and 220. Thus, there is no change in the point that forms part of the force transmission bodies T1, T2. Similarly, the positions of the upper diaphragms 135 and 145 shown in FIG. 11 are also moved to the lower surface side of the upper substrate 100A (not shown).

  In short, according to the present invention, a plurality of N sets of upper diaphragms are formed on the upper substrate 100, and a plurality of N sets of lower diaphragms are formed on the lower substrate 200. The upper substrate 100 is supported above the lower substrate 200 via a total of N columnar bodies, and is connected to the common electrode provided on the lower surface of the lower diaphragm and below the common electrode. This is a technique that can be widely applied to a force detection device having a function of detecting a force acting on the upper substrate 100 based on a capacitance value of a capacitive element formed by provided individual electrodes.

<<< §4. Basic technical idea of the present invention >>>
Now, let us consider the material of each part when mass-producing the prior art embodiments described so far. Specifically, consider the case of configuring the force detection device shown in FIG. In the above description, the upper substrate 100A and the lower substrate 200 are made of a metal such as stainless steel, aluminum, titanium, and the support substrate 300 is made of an insulating substrate such as a glass epoxy PCB substrate. The individual electrodes E11 to E45 may be configured by a layer obtained by patterning a metal such as copper or gold.

  The first merit of configuring the lower substrate 200 with a metal material is that the lower diaphragms 215, 225, 235, and 245 are configured as a part of the lower substrate 200 (a portion that is thinner and more flexible than the other portions). Therefore, the common electrode facing the individual electrodes E11 to E15, the common electrode facing the individual electrodes E21 to E25, the common electrode facing the individual electrodes E31 to E35, and the common electrode facing the individual electrodes E41 to E45. This is a point that can function as an electrode. The second merit of forming the lower substrate 200 from a metal material is that the diaphragm made of metal has a property as a leaf spring, and the relationship between the applied external force and the displacement caused by the external force is a hook. This is the point that a nearly linear relationship can be maintained according to the law. This second merit is also an advantage when the upper substrate 100 is made of a metal material. Therefore, if attention is paid to the function of the diaphragm, the upper substrate 100A and the lower substrate 200 in the force detection device shown in FIG. 16 are preferably made of metal.

  However, the biggest disadvantage when the upper substrate 100A and the lower substrate 200 are made of metal is the manufacturing cost. As already described, the metal processing with the lowest cost is press processing, but it is not preferable to form the upper substrate 100A and the lower substrate 200 shown in FIG. 16 by metal pressing. This is because when a metal material is pressed, mechanical stress remains inside, and this residual stress adversely affects the above-described properties of the diaphragm as a leaf spring. Specifically, due to the influence of residual stress, the position of the zero point is shifted depending on the lot, or the linear characteristic of the detection output is lost. For this reason, in order to configure the upper substrate 100A and the lower substrate 200 with a metal material, it is necessary to adopt a relatively expensive processing method such as cutting, electric discharge processing, and wire cut processing, and the manufacturing cost increases. I cannot help it.

  Another disadvantage when the upper substrate 100A and the lower substrate 200 are made of metal is a problem that electrical noise components are likely to be mixed into the detection result. For example, in the apparatus shown in FIG. 16, if the upper substrate 100A and the lower substrate 200 are made of metal, the whole of them constitutes a block of conductors, so that, for example, when applying an external force Furthermore, if a potential fluctuation occurs due to a hand touching a part of the upper substrate 100A, the potential fluctuation is also transmitted to the lower diaphragms 215, 225 and the like functioning as a common electrode. It becomes a factor which gives a noise component to a detection system.

  In order to overcome such demerits, in the present invention, the upper substrate 100A and the lower substrate 200 in the apparatus shown in FIG. Is used. The resin material is extremely easy to be processed into an arbitrary shape by shaping using a mold, and a substrate having an arbitrary shape can be mass-produced at a low cost. Further, since a general resin material has an insulating property, it does not serve as a medium for electrical noise from the outside. Therefore, the above-mentioned “demerit using a metal material” can be overcome.

  However, in this case, it is necessary to provide a metal plating layer at least on the lower surfaces of the lower diaphragms 215 and 225 (and not shown in FIG. 16, but also on the lower surfaces of the lower diaphragms 235 and 245). This is because the common electrode facing each of the individual electrodes E11 to E45 needs to be composed of a metal plating layer. Thus, even if each substrate is made of a resin material, if a metal plating layer is formed on the lower surface of the lower diaphragm, it can function as a common electrode facing each individual electrode.

  In general, a structure made of a resin material has a hysteresis with respect to mechanical deformation, and an accurate linearity between an applied external force and a deflection (displacement) caused by the external force. Cannot be obtained. This can be easily understood by considering urethane resin as an extreme example. When an external force is applied to a block made of a urethane resin and compressed, accurate linearity is not seen between the degree of compression and the applied external force. Moreover, even after the external force is removed, the block made of urethane resin does not immediately return to the original state, and the influence of the residual stress is maintained for a while. That is, a structure made of a resin material is not suitable for use as a leaf spring according to the hook law.

  However, according to an experiment conducted by the inventors of the present application, even when the diaphragm is made of a resin material, if a metal plating layer is formed on at least one surface of the diaphragm, the whole is close to a diaphragm made of metal. Mechanical deformation characteristics were obtained. For example, in the example shown in FIG. 16, the lower diaphragms 215 and 225 having a thickness of 1 mm are formed on a part of the lower substrate 200 having a thickness of 6 mm using a resin material of PPS, and the thickness is 10 on the lower surface thereof. When a plating layer having a thickness of ˜20 μm (a gold layer plated on a copper layer) was formed, the mechanical deformation characteristics of the diaphragm almost conformed to Hooke's law. That is, even when the diaphragm is made of a resin material, a linear mechanical deformation characteristic close to that of a metal leaf spring can be obtained by forming a metal plating layer on the lower surface thereof.

  Of course, in order to obtain a linear mechanical deformation characteristic closer to that of a metal leaf spring, the upper and lower surfaces of the lower diaphragms 215 and 225 (and although not shown in FIG. 16, the lower diaphragms 235 and 245 It is preferable to form a metal plating layer on both the upper and lower surfaces. For the upper diaphragm, for the same reason, it is preferable to form a metal plating layer on both the upper and lower surfaces.

<<< §5. Embodiment of the Invention >>
Here, a specific embodiment in which the present invention is applied to the force detection device shown in FIG. 16 will be described with reference to side sectional views shown in FIGS. FIGS. 17 to 24 all show a side cross section along the cutting line 10-10 in the prior art embodiment shown in FIG. 9, but the structure of the side cross section along the cutting line 11-11 is also shown. Exactly the same. The operation for detecting the force is the same as that of the apparatus according to the prior art embodiment described in §1 to §3.

(1) First Embodiment FIG. 17 is a cross-sectional side view of a force detection device according to a first embodiment of the present invention. As shown in the figure, main components of the apparatus are a force receiving body 400, an upper substrate 500, a lower substrate 600, a detection substrate 700, a detection circuit 750, a pedestal 800, and an apparatus housing 900.

  The force receiving member 400 is a substrate-like component having a square upper surface, and is joined to the upper substrate 500 so as to be positioned above the upper substrate 500. The force receiving member 400 has a function of receiving a force to be detected and transmitting the force to the upper substrate 500. As shown in the figure, grooves G1 are formed in several places on the upper surface of the periphery of the force receiving member 400, and are fixed to the upper surface of the upper substrate 500 by screws N1. The groove portion G2 formed on the upper surface of the force receiving member 400 is a screw groove having a screw thread formed therein, and various objects (forces to be detected can be directly applied thereto as necessary. Can be attached. The material of the force receiving member 400 may be a metal or an insulating material such as a resin. However, in consideration of attaching and detaching an object using the screw groove G2, in order to ensure mechanical durability, The power receiving member 400 is preferably made of a metal material.

  The upper substrate 500 is a component corresponding to the upper substrate 100A in FIG. 16, and is configured by a resin material such as ABS, PPS, and Delrin (registered trademark) in the present invention. A groove portion G3 is provided on the upper surface of the upper substrate 500. As a result, an upper diaphragm 510 having a thickness smaller than other portions and having flexibility is formed in part (actually, 4). The upper substrate 500 has an upper columnar body 520 extending downward from the center of the upper diaphragm 510.

  On the other hand, the lower substrate 600 is a component corresponding to the lower substrate 200 in FIG. 16, and in the case of the present invention, is also made of a resin material such as ABS, PPS, Delrin (registered trademark). The lower substrate 600 is disposed below the upper substrate 500 with a gap G4 interposed therebetween. By providing a groove G5 on the upper surface, the lower diaphragm 600 is thinner and flexible than other portions. 610 is formed in a part (actually, it is formed in four places). The lower substrate 600 has a lower columnar body 620 extending upward from the center of the lower diaphragm 610. Here, the lower diaphragm 610 is formed at a position such that the lower surface position of the lower diaphragm 610 is higher than the lower surface position of the lower substrate 600. As a result, a gap G6 is formed between the lower surface of the lower diaphragm 610 and the upper surface of each individual electrode E.

  The lower end of the upper columnar body 520 and the upper end of the lower columnar body 620 are joined to each other by a screw N2, and one force transmission body is formed by both the columnar bodies. Actually, a total of four force transmission bodies are formed, and the upper substrate 500 and the force receiving body 400 are supported above the lower substrate 600 through these four force transmission bodies.

  As described above, by forming the upper substrate 500 and the lower substrate 600 from a resin material, it is possible to greatly reduce the manufacturing cost. The resin material can be molded into an arbitrary shape and is suitable for mass production. Moreover, if it is manufactured by shaping using a mold, there will be no problem of residual stress as in press working on metal.

  The detection substrate 700 is a component corresponding to the support substrate 300 in FIG. 16, and the individual electrodes E11 to E45 are formed on the upper surface thereof as shown in the top view of FIG. 13 (in FIG. 17). In order to avoid complication of the figure, each individual electrode is simply indicated by the symbol E). Since the individual electrodes E11 to E45 need to be electrically insulated from each other, the detection substrate 700 (at least the upper surface thereof) is made of an insulating material. In the case of the example shown here, the detection board 700 also serves as a circuit board of the detection circuit, is configured by a glass epoxy PCB board, and is joined to the lower surface of the lower board 600 by screws N3. A circular region where the individual electrodes E11 to E15 are formed, a circular region where the individual electrodes E21 to E25 are formed, a circular region where the individual electrodes E31 to E35 are formed, and the individual electrodes E41 to E45 are formed. Each of the circular areas constitutes an independent detection area, and each detection area is located below the lower diaphragm 610.

  The detection circuit 750 is a circuit disposed on the lower surface of the detection substrate 700, and is accommodated in a gap G7 secured below the detection substrate 700. For convenience, the detection circuit 750 is shown as one block in FIG. 17, but actually, this detection circuit is composed of various circuit components formed on the lower surface of the detection substrate 700. As described above, the detection board 700 also serves as a circuit board, and the detection circuit 750 for obtaining the detection value of the force based on the principle of FIG. It is comprised and the function which detects the force which acted on the power receiving body 400 based on the bending condition of the lower diaphragm 610 is fulfill | performed.

  The pedestal 800 is a component fixed to the upper surface of the bottom of the apparatus housing 900, and a gap G7 for accommodating the detection circuit 750 is secured in the upper part. A screw N4 is inserted into a groove G8 provided around the base 800, and the lower substrate 600 is fixed to the upper surface of the base 800 by the screw N4. Thus, the lower substrate 600 is fixed to the apparatus housing 900 via the pedestal 800. The device housing 900 is a box-like structure with an open top surface, and fulfills the function of accommodating the main part of the force detection device described above. The pedestal 800 and the device casing 900 may be made of a metal material or an insulating material such as a resin.

  A common electrode Ec made of a metal plating layer is formed on the lower surface of the lower diaphragm 610. In the figure, this plating layer is indicated by a bold line. The individual electrode E is disposed at a position facing the common electrode Ec provided for each detection region, and a capacitive element is formed by each individual electrode E and the common electrode Ec. The detection circuit 750 performs a process of detecting a force acting on the force receiving body 400 based on the capacitance values of the plurality of capacitive elements.

  In order to perform such detection processing in the detection circuit 750, it is necessary to perform electrical wiring from the individual electrodes E and the common electrode Ec to the detection circuit 750. Therefore, in the illustrated embodiment, the wiring layer W1 (thick line in the figure) is extended from the common electrode Ec formed on the lower surface of the lower diaphragm 610 so as to travel along the side surface of the groove G6, and the end of the wiring layer W1 is The bottom surface of the lower substrate 600 is reached. In practice, such a wiring layer W1 may be formed of a metal plating layer in the same manner as the common electrode Ec.

  As described above, the detection substrate 700 is joined to the lower surface of the lower substrate 600 by the screw N3 inserted through the through hole. Therefore, if this screw N3 is a conductive screw made of metal or the like, and this conductive screw N3 is inserted through the end of the wiring layer W1 and screwed into the lower portion of the lower substrate 600, this conductive Wiring between the common electrode Ec and the detection circuit 750 can be performed using the sex screw N3. That is, to avoid complication of the figure, although not depicted in FIG. 17, if wiring is provided from the conductive screw N <b> 3 to the detection circuit 750 along the lower surface of the detection substrate 700, the wiring to the conductive The wiring to the common electrode Ec can be performed by following the path of the sex screw N3 to the wiring layer W1 to the common electrode Ec.

  On the other hand, wiring between each individual electrode E and the detection circuit 750 can be performed through a through hole provided in the detection substrate 700. The wiring W2 shown in the figure indicates a wiring provided through such a through hole, and the wiring W3 extends from the wiring W2 to the detection circuit 750 provided along the lower surface of the detection substrate 700. Wiring. In FIG. 17, only wirings for some of the individual electrodes E are shown in order to avoid complication of the figure, but in reality, such individual through holes are provided to the individual electrodes E. Wiring is performed independently.

  Since the upper substrate 500 and the lower substrate 600 are made of an insulating resin material, even if the power receiving body 400 is made of a metal material, an electrical noise component that has entered the power receiving body 400 is not generated. In addition, it is not transmitted to the capacitive element (for example, the common electrode Ec) or the detection circuit 750 through the upper substrate 500 and the lower substrate 600. Thus, in the force detection device according to this embodiment, it is possible to reduce manufacturing costs and prevent electrical noise from being mixed.

  In FIG. 17, for convenience of illustration, the dimensional ratio of each part is not accurately reproduced. Therefore, the actual size of each main part is illustrated below for reference. First, the force receiving member 400, the upper substrate 500, and the lower substrate 600 are all square substrates of approximately 30 mm square, the thickness of the force receiving member 400 is 8 mm, the thickness of the upper substrate 500 is 6 mm, and the thickness of the lower substrate 600. Is 6 mm. The distance between the lower surface of the upper substrate 500 and the upper surface of the lower substrate 600 (the distance in the vertical direction of the gap G4) is 0.2 mm, the thickness of the upper diaphragm 510 is 1.5 mm, and the thickness of the lower diaphragm 610 is 1.5 mm. It is. The individual electrode E has a thickness of 10 μm, and the common electrode Ec (metal plating layer) has a thickness of 10 to 20 μm. Further, each of the diaphragms 510 and 610 has a disk shape with a diameter of 8 mm, and the upper columnar portion 520 and the lower columnar portion 620 have a columnar shape with a diameter of 4.5 mm.

(2) Second Embodiment FIG. 18 is a side sectional view of a force detection device according to a second embodiment of the present invention. The device according to the second embodiment is substantially the same as the device according to the first embodiment described above, but the only difference is not only the lower surface of the lower diaphragm 610 but also the upper surface thereof. The plating layer P is formed.

  The metal plating layer provided on the lower surface of the lower diaphragm 610 is a component that functions as the common electrode Ec, and is an indispensable component on the electrical detection principle of the force detection device. On the other hand, the metal plating layer P provided on the upper surface of the lower diaphragm 610 does not contribute to electrical detection at all. However, it can play the role of improving the mechanical characteristics of the lower diaphragm 610 as a leaf spring.

  That is, as described in §4, a diaphragm made of a resin material has a hysteresis with respect to mechanical deformation as it is, and like a diaphragm made of metal, it can be used as a leaf spring in accordance with Hooke's law. It is inappropriate. When the metal plating layer (common electrode Ec) is formed on the lower surface of the lower diaphragm 610 as in the first embodiment shown in FIG. 17, the hysteresis characteristic peculiar to the resin material is considerably improved. However, in order to further improve this hysteresis characteristic and use it as a leaf spring that complies with Hooke's law and to ensure sufficient linearity, it is preferable to form a metal plating layer P on the upper surface of the lower diaphragm 610.

  In the second embodiment shown in FIG. 18, metal plating layers are formed on the upper and lower surfaces of the lower diaphragm 610, and the diaphragm main body portion made of a resin material is sandwiched from the upper and lower surfaces by the metal plating layer. It has become. Thereby, the hysteresis characteristic in the lower diaphragm 610 is greatly improved, and linearity close to that of a metal diaphragm can be obtained.

(3) Third Embodiment FIG. 19 is a side cross-sectional view of a force detection device according to a third embodiment of the present invention. The device according to the third embodiment is substantially the same as the device according to the second embodiment described above, but the major difference is not only between the upper and lower surfaces of the lower diaphragm 610 but also the upper and lower surfaces of the upper diaphragm 510. Is also a point where a metal plating layer P (indicated by a thick line) is formed.

  The lower diaphragm 610 has a direct influence on the capacitance value of the capacitive element, but the upper diaphragm 510 functions as a path for transmitting an external force applied to the force receiving body 400 to the lower diaphragm 610. From the viewpoint of obtaining a detection value having the characteristics, it is preferable that the mechanical deformation characteristic of the upper diaphragm 510 is also made to have a characteristic that obeys the Hooke's law as much as possible by eliminating hysteresis.

  In the embodiment shown in FIG. 19, since the main body portion of the upper diaphragm 510 made of a resin material is also sandwiched from the upper and lower surfaces by the metal plating layer P, the hysteresis characteristics are greatly improved, and The linearity close to the diaphragm can be obtained.

  In the device according to the third embodiment, the force receiving member 400 and the device housing 900 are made of a metal material such as stainless steel, and the force receiving member 400 and the device housing 900 are separated from each other. A conductive wire W0 that electrically short-circuits between them is provided. Here, if the device casing 900 is used with a ground potential (so-called grounding), an electrical noise component that has entered the power receiving body 400 is grounded via the conductive wire W0 and the device casing 900. Since the potential can be released to the electric potential, it is possible to surely prevent the electric noise from entering the detection circuit 750.

(4) Fourth Embodiment FIG. 20 is a side sectional view of a force detector according to a fourth embodiment of the present invention. The device according to the fourth embodiment is basically the same as the device according to each of the above-described embodiments. However, the feature is that the surface of the upper substrate 500 and the lower substrate 600 is substantially entirely covered with metal. The plating layer P (shown by a thick line) is formed.

  However, it is not preferable to form the metal plating layer P on the entire surface of the upper substrate 500 and the lower substrate 600 from the viewpoint of the operation of the force detection device. First, when the power receiving body 400 is made of a metal material, the surface of the power receiving body 400 and the plating layer P are in a conductive state. There is a possibility of encouraging contamination. Second, considering that various wiring layers are formed on the lower surface of the detection substrate 700, unnecessary capacitance elements are formed by these wiring layers and the plating layer P. Causes an increase in undesirable parasitic capacitance.

  Although the force detection device according to the fourth embodiment shown in FIG. 20 has such a demerit, in practice, there are also merits commensurate with it. That is an advantage that the manufacturing cost can be greatly reduced. In the first to third embodiments described so far, the metal plating layer P is formed only on a specific part of the surface of the upper substrate 500 or the lower substrate 600. However, in order to form the metal plating layer P only on a specific part, the part other than the specific part is masked and the plating process is performed, or after the plating process is performed on the entire surface, the specific part is formed. An extra step is required, such as a step of peeling the plating layer other than the portion, and as a result, the manufacturing cost increases. On the other hand, in the case of the force detection device according to the fourth embodiment shown in FIG. 20, it is only necessary to form the plating layer P on the entire surface of the upper substrate 500 and the lower substrate 600, so that the above-described extra steps are unnecessary. As a result, the manufacturing cost can be reduced.

(5) Fifth Embodiment FIG. 21A is a side sectional view of a force detection device according to a fifth embodiment obtained by changing a part of the fourth embodiment shown in FIG. FIG. 21B is a partially enlarged view thereof. As described above, in the force detection device according to the fourth embodiment shown in FIG. 20, the surface of the force receiving body 400 and the plating layer P are in a conductive state, and thus the electric power to the common electrode Ec and the detection circuit 750 is obtained. There is a demerit that promotes the mixing of noise. The fifth embodiment shown here is devised to eliminate such disadvantages.

  That is, in the fifth embodiment, a plating notch 525 in which no plating layer is formed is provided at a connection portion between the upper substrate 500 and the lower substrate 600, and the plating layer formed on the surface of the upper substrate 500 and the lower portion The plating layer formed on the surface of the substrate 600 is electrically insulated. This situation is clearly shown in the partially enlarged view of FIG. That is, in the case of this embodiment, the upper substrate 500 and the lower substrate 600 are connected by the upper columnar body 520 and the lower columnar body 620, but a plating layer is formed on the lower surface of the upper columnar body 520. A plating notch 525 that is not formed is provided. By interposing the plating notch 525, the plating layer formed on the surface of the upper substrate 500 and the plating layer formed on the surface of the lower substrate 600 are electrically insulated. For this reason, electrical noise generated on the surface of the force receiving member 400 can be blocked by the plating notch 525, and can be prevented from being mixed into the common electrode Ec and the detection circuit 750. Of course, the plating notch may be provided on the upper end surface of the lower columnar body 620.

(6) Variations of the columnar body that functions as a force transmission body Here, some variations of the columnar body that functions as a force transmission body will be described. In the first to fifth embodiments (FIGS. 17 to 21) described so far, the columnar body functioning as a force transmission body includes an upper columnar body 520 and a lower diaphragm 610 extending downward from the center of the upper diaphragm 510. Although it is configured by joining the lower columnar body 620 extending upward from the center, the columnar body is not necessarily required to adopt such a configuration. Hereinafter, some modifications of this columnar body will be described.

  FIG. 22 is a partial sectional side view showing a first modification of the columnar body. In this figure, for convenience of explanation, only the upper substrate 500A and the lower substrate 600A are extracted and shown. An upper diaphragm 510 is formed on the upper substrate 500A, but the lower surface of the upper diaphragm 510 is flat, and no columnar body is provided. On the other hand, in the lower substrate 600A, a lower diaphragm 610 is formed sandwiched between the grooves G5 and G6, and a columnar body 630 extending upward from the center thereof is provided. The upper end of the columnar body 630 is joined to the center of the lower surface of the upper diaphragm 510, and the upper substrate 500A is supported above the lower substrate 600A via the columnar body 630. The columnar body 630 is set to a length suitable for securing the gap G4.

  Of course, the upper substrate 500A and the lower substrate 600A are made of a resin material, and a metal plating layer P is formed on a predetermined portion of the surface thereof. Even with such a structure, the same functions as those of the first to fifth embodiments described so far can be achieved.

  On the other hand, FIG. 23 is a partial side sectional view showing a second modification of the columnar body. In this figure, for convenience of explanation, only the upper substrate 500B and the lower substrate 600B are extracted and shown. The lower substrate 600B is formed with a lower diaphragm 610 sandwiched between the grooves G5 and G6, but the upper surface of the lower diaphragm 610 is flat, and no columnar body is provided. On the other hand, an upper diaphragm 510 is formed on the upper substrate 500B, and a columnar body 530 extending downward from the center thereof is provided. The lower end of the columnar body 530 is joined to the center of the upper surface of the lower diaphragm 610, and the upper substrate 500B is supported above the lower substrate 600B via the columnar body 530. The columnar body 530 is set to a length suitable for securing the gap G4.

  Of course, the upper substrate 500B and the lower substrate 600B are made of a resin material, and a metal plating layer P is formed on a predetermined portion of the surface thereof. Even with such a structure, the same functions as those of the first to fifth embodiments described so far can be achieved.

  Further, FIG. 24 is a partial side sectional view showing a third modification of the columnar body. In this figure, for convenience of explanation, only the upper substrate 500C and the lower substrate 600C are extracted and shown. An upper diaphragm 510 is formed on the upper substrate 500C, but the lower surface of the upper diaphragm 510 is flat and no columnar body is provided. The lower substrate 600C is formed with a lower diaphragm 610 sandwiched between the grooves G5 and G6. The upper surface of the lower diaphragm 610 is flat, and no columnar body is provided. In this modification, a columnar body 930 is provided as a separate body, the upper end of which is joined to the center of the lower surface of the upper diaphragm 510, and the lower end thereof is joined to the center of the upper surface of the lower diaphragm 610. As a result, the upper substrate 500C is supported above the lower substrate 600C via the columnar body 930. The columnar body 930 is set to a length suitable for securing the gap G4.

  Of course, the upper substrate 500C and the lower substrate 600C are made of a resin material, and a metal plating layer P is formed on a predetermined portion of the surface thereof. The columnar body 930 may be made of a resin material like the upper substrate 500C and the lower substrate 600C, or may be made of another material. Even with such a structure, the same functions as those of the first to fifth embodiments described so far can be achieved.

(7) Device to reduce hysteresis characteristics So far, it has been described that a diaphragm made of a resin material generates hysteresis characteristics (characteristics that deviate from linear characteristics in accordance with Hooke's law). It is also induced by the joining. In the first to fifth embodiments (FIGS. 17 to 21) described so far, the upper columnar body 520 and the lower columnar body 620 are joined using the screw N2, but such a screw N2 is used. Even with the joining by means of, hysteresis characteristics occur between the force applied to the diaphragm and the displacement.

  The inventor of the present application has confirmed that a structure as shown in FIG. 25 is effective as a device for reducing such hysteresis characteristics. FIG. 25 is an enlarged view of the periphery of the screw N2 in the embodiment shown in FIGS. 17 to 21, and a raised portion 515 is formed near the center of the upper surface of the upper diaphragm 510, and the raised portion 515 and the upper diaphragm 510 are inserted. The state where the upper columnar body 520 and the lower columnar body 620 are joined by the screw N2 is shown. As described above, when the raised portion 515 is formed in the vicinity of the center of the upper surface of the upper diaphragm 510 and the screw N2 is inserted, the hysteresis characteristic of the upper diaphragm 510 is suppressed as compared with the case where the raised portion 515 is not formed. it can.

  Such formation of the raised portion 515 is also effective for the modification shown in FIG. FIG. 26 is an enlarged view around the screw N2 showing a state in which the raised portion 515 is formed in the modification shown in FIG. Of course, the formation of the raised portion 515 is also effective for the modification shown in FIG. 24, and in this case, the screw N <b> 2 is fixed to the columnar body 930. In the case of the modification shown in FIG. 23, since it is generally not preferable to insert the screw N2 through the lower diaphragm 610, an adhesive or the like is used for joining between the columnar body 530 and the lower diaphragm 610. Although it is preferable to adopt the method, if the screw N2 is used for joining, the raised portion 515 can be formed in the vicinity of the center of the upper surface of the upper diaphragm 510.

(8) Variations of substrate shape and columnar body arrangement In carrying out the present invention, there are various shapes such as the force receiving body 400, the upper substrate 500, the lower substrate 600, the number of each force transmitting body and the arrangement thereof. There are variations. For example, in the example described so far, the force receiving member 400, the upper substrate 500, and the lower substrate 600 are all square substrates, but it is of course possible to configure them by circular substrates. .

  FIG. 27 is a top view of a lower substrate 600D according to a modified example having a circular outline. A thin lower diaphragm 610D is provided at four locations, and a lower columnar body 620D extending upward is provided at the center thereof. The lower substrate 600 in the embodiment shown in FIGS. Although the outline of the lower substrate 600D is circular, the whole is a disk-shaped substrate. As described above, when the disk-shaped lower substrate 600D is used, it is preferable that the upper substrate 500 and the force receiving body 400 are similarly formed into a disk shape.

  Of course, there are various variations in the number and arrangement of each force transmission body. For example, in Patent Document 1 and Patent Document 2 described above, an example in which the arrangement of four force transmission bodies is changed, or three Alternatively, an example using two force transmission bodies is also disclosed. The present invention can also be applied to such variations.

(9) Modified Example Using Displacement Plate Supported by Beam Part In the embodiments described so far, all have a structure in which the upper end and the lower end of the columnar body are supported by a diaphragm. For example, in the example shown in FIG. 27, the lower columnar body 620D extends upward from the center of the lower diaphragm 610D (in the direction perpendicular to the paper surface), and the lower end thereof is supported by the lower diaphragm 610D. The lower diaphragm 610D is a disk-like structure, and is thin as compared with other portions of the lower substrate 600D, and therefore has flexibility as a whole. In this way, instead of using a “diaphragm that is totally flexible because it is thinner than the rest of the substrate” as a structure that supports the end of the columnar body, It is also possible to use a “supported displacement plate”.

  FIG. 28 is a top view of a lower substrate 600E according to such a modification. This lower substrate 600E is, so to speak, a structure in which in the lower substrate 600D shown in FIG. 27, “m” -shaped through slits H (slits penetrating in the thickness direction) are formed at four peripheral portions of the lower diaphragm 610D. be able to. By forming such a through slit H, a displacement plate 610E having a fan blade shape and a beam portion 640E that supports the displacement plate 610E from four directions are formed. Both the displacement plate 610E and the beam portion 640E are thin portions compared to other portions of the lower substrate 600E. In particular, since the beam portion 640E is narrow, it has sufficient flexibility. Become. Therefore, when a force from the lower columnar body 620E is applied, the deflection concentrates exclusively on the beam portion 640E, and the displacement plate 610E is displaced. Of course, since the common electrode Ec is formed on the lower surface of the displacement plate 610E, the displacement of the displacement plate 610E is detected by the detection circuit as a change in the capacitance value of the capacitive element.

  In FIG. 28, the lower substrate 600E is shown as an example. However, the upper substrate 500 has a structure that supports the end of the columnar body in the same manner. Instead of using a “flexible diaphragm”, it is possible to use a “displacement plate supported by a beam portion”. In short, a part of the upper substrate is formed with an “upper flexible part having a thickness thinner than that of the other part and at least a part of which is flexible”. It is only necessary to form a “lower flexible portion” that is thin and at least partially flexible. The example shown in FIG. 27 is an example in which the lower flexible portion is realized by a “diaphragm 610D that is totally flexible because it is thinner than other portions of the substrate 600D”. In this example, the lower flexible portion is realized by “the displacement plate 610E and the beam portion 640E that supports the displacement plate 610E from the periphery”. In the latter case, it is sufficient that at least the beam portion 640E has flexibility, and the displacement plate 610E may not have flexibility.

It is a perspective view (a part is block diagram) which shows the structure of the force detection apparatus which concerns on the prior art embodiment which becomes the origin of this invention. It is a front view which shows the fundamental operation | movement principle of the force detection apparatus shown in FIG. It is a sectional side view (cross-sectional view cut by xz plane) which shows an example of the multi-axis force sensor suitable for using as the 1st sensor 21-the 4th sensor 24 in the force detection apparatus shown in FIG. FIG. 4 is a top view of the multi-axis force sensor shown in FIG. 3. It is a top view of the support body 40 in the multi-axis force sensor shown in FIG. 3 (a broken line has shown the position of the hook-shaped connection member). FIG. 4 is a side sectional view showing a state when a force + fx in the x-axis positive direction is applied to the multi-axis force sensor shown in FIG. 3. FIG. 4 is a side sectional view showing a state when a force −fx in the negative x-axis direction is applied to the multi-axis force sensor shown in FIG. 3. FIG. 4 is a side sectional view showing a state when a force −fz in the negative z-axis direction is applied to the multi-axis force sensor shown in FIG. 3. It is a top view of the force detection apparatus which concerns on prior art embodiment which becomes the origin of this invention. FIG. 10 is a first side cross-sectional view of a force detection device according to a prior art embodiment on which the present invention is based, and shows a cross section of the device shown in FIG. 9 cut along a cutting line 10-10. It is the 2nd sectional side view of the force detection apparatus which concerns on the prior art embodiment which becomes the origin of this invention, and the cross section which cut | disconnected the apparatus shown in FIG. 9 along the cutting line 11-11 is shown. It is a cross-sectional view which shows the state which cut | disconnected the force detection apparatus which concerns on the prior art embodiment which becomes the origin of this invention along XY plane. It is a top view of the support body 300 of the force detection apparatus which concerns on prior art embodiment which becomes the origin of this invention. It is a table | surface which shows the detection principle of each force component by the force detection apparatus based on prior art embodiment which becomes the origin of this invention, and the change of the electrostatic capacitance value of each capacitive element when each force component acts on a power receiving body This aspect is shown. It is a figure which shows the detection principle of each force component shown in FIG. 14 using numerical formula. FIG. 11 is a side sectional view of a force detection device according to another prior art embodiment on which the present invention is based, in the same position as the side sectional view of FIG. 10 (position equivalent to the cutting line 10-10 shown in FIG. 9) A cut section is shown. FIG. 17 is a side sectional view of a force detection device according to a first embodiment of the present invention (a mode in which a practical improvement is made based on the prior art embodiment shown in FIG. 16). FIG. 18 is a side sectional view of a force detection device according to a second embodiment obtained by changing a part of the first embodiment shown in FIG. 17. FIG. 18 is a side sectional view of a force detection device according to a third embodiment obtained by changing a part of the first embodiment shown in FIG. 17. FIG. 18 is a side sectional view of a force detection device according to a fourth embodiment obtained by changing a part of the first embodiment shown in FIG. 17. (A) in the upper stage is a side sectional view of the force detection device according to the fifth embodiment obtained by changing a part of the fourth embodiment shown in FIG. 20, and (b) in the lower stage is FIG. It is a fragmentary sectional side view which shows the 1st modification of the columnar body in embodiment shown in FIGS. It is a fragmentary sectional side view which shows the 2nd modification of the columnar body in embodiment shown in FIGS. It is a fragmentary sectional side view which shows the 3rd modification of the columnar body in embodiment shown in FIGS. It is a partial expanded side sectional view showing the 1st modification of a screw attachment part in an embodiment shown in Drawing 17-Drawing 20. It is a partial expanded side sectional view showing the 2nd modification of a screw attachment part in an embodiment shown in Drawing 17-Drawing 20. It is a top view of lower board | substrate 600D which concerns on the modification which made the outline circular. It is a top view of the lower board | substrate 600E which concerns on the modification using the displacement plate 610E supported by the beam part 640E instead of lower diaphragm 610D shown in FIG.

Explanation of symbols

10: force receiving body 11: first force transmitting body 12: second force transmitting body 13: third force transmitting body 14: fourth force transmitting body 20: support body 21: first sensor 22: first 2 sensor 23: 3rd sensor 24: 4th sensor 30: detection circuit 40: support body 50: bowl-shaped connection member 51: Diaphragm (common electrode)
52: Side wall part 53: Fixed part 60: Force transmission body 100, 100A: Upper substrate 110, 110A: Upper columnar body 115, 115A: Upper diaphragm 120, 120A: Upper columnar body 125, 125A: Upper diaphragm 130: Upper columnar body 135: Upper diaphragm 140: Upper columnar body 145: Upper diaphragm 200: Lower substrate 210: Lower columnar body 215: Lower diaphragm 220: Lower columnar body 225: Lower diaphragm 230: Lower columnar body 235: Lower diaphragm 240: Lower columnar body 245 : Lower diaphragm 300: Support substrate 400: Power receiving bodies 500, 500 A, 500 B, 500 C: Upper substrate 510: Upper diaphragm 515: Raised portion 520: Upper columnar body 525: Plate notch 530: Columnar bodies 600, 600 A, 600 B, 600C, 600D 600E: Lower substrate 610, 610D: Lower diaphragm 610E: Displacement plates 620, 620D, 620E: Lower columnar body 630: Columnar body 640E: Beam portion 700: Detection substrate 750: Detection circuit 800: Base 900: Device housing 930: Columns C11 to C45: Capacitance elements / capacitance elements E, E1 to E5: Individual electrodes E11 to E15: Individual electrodes E21 to E25 for the first sensor: Individual for the second sensor Individual electrodes E31 to E35: Individual individual electrodes E41 to E45 for the third sensor: Individual individual electrodes Ec for the fourth sensor: Common electrode Fx: Force fx in the X axis direction, fx ': In the x axis direction Force Fy: Force in the Y-axis direction Fz: Force in the Z-axis direction fz: Pulling force / pressing force G1-G8 acting on the support: Groove / gap G11-G34, G11A, G12 : Groove H: Through slit Mx: Moment about X axis My: Moment about Y axis Mz: Moments about Z axis N1 to N4: Screw O: Origin of coordinate system P: Metal plating layer P1 to P4: Upper substrate Points S1 to S4 on 100: Multi-axis force sensors T1 to T4: Force transmission bodies W0 to W3: Wiring XYZ: Coordinate system having an origin at the center position of the force receiving body xy: Coordinate system defined on the upper surface of the support θ1, θ2: Inclination angle

Claims (17)

A power receiving body that receives the force to be detected;
An upper substrate having an upper columnar body that is formed in a part of “an upper flexible part that is thinner than other parts and at least a part of which is flexible” and extends downward from the center of the upper flexible part; ,
A lower substrate having a lower columnar body that is formed in a part of “a lower flexible part that is thinner than other parts and at least a part of which is flexible” and extends upward from the center of the lower flexible part; ,
A plurality of individual electrodes are formed in the detection region on the upper surface, and a detection substrate made of an insulating material;
An apparatus housing to which the lower substrate is fixed;
A detection circuit for detecting a force acting on the force receiving body based on a degree of bending of the lower flexible portion;
With
The upper substrate and the lower substrate are made of a resin material,
The lower end of the upper columnar body and the upper end of the lower columnar body are joined to each other, and through these both columnar bodies, the upper substrate is supported above the lower substrate,
The force receiving member is bonded to the upper substrate so as to be positioned above the upper substrate;
The detection substrate is bonded to the lower surface of the lower substrate so that the detection region is located below the lower flexible portion,
The lower flexible portion is formed at a position where the lower surface position of the lower flexible portion is higher than the lower surface position of the lower substrate, and the lower surface of the lower flexible portion and each of the individual electrodes are formed. A gap is formed between the upper surface,
A common electrode made of a metal plating layer is formed on the lower surface of the lower flexible portion,
The detection circuit detects a force acting on the force receiving body based on capacitance values of a plurality of capacitive elements configured by the individual electrodes and the common electrode. . A power receiving body that receives the force to be detected;
An upper substrate on which a “thin flexible portion at least partially flexible with at least a portion being thinner than other portions” is formed;
A lower substrate having a columnar body that is formed in a part of “a lower flexible part that is thinner than other parts and at least a part of which is flexible” and extends upward from the center of the lower flexible part;
A plurality of individual electrodes are formed in the detection region on the upper surface, and a detection substrate made of an insulating material;
An apparatus housing to which the lower substrate is fixed;
A detection circuit for detecting a force acting on the force receiving body based on a degree of bending of the lower flexible portion;
With
The upper substrate and the lower substrate are made of a resin material,
The upper end of the columnar body is joined to the lower surface center of the upper flexible portion, and the upper substrate is supported above the lower substrate via the columnar body,
The force receiving member is bonded to the upper substrate so as to be positioned above the upper substrate;
The detection substrate is bonded to the lower surface of the lower substrate so that the detection region is located below the lower flexible portion,
The lower flexible portion is formed at a position where the lower surface position of the lower flexible portion is higher than the lower surface position of the lower substrate, and the lower surface of the lower flexible portion and each of the individual electrodes are formed. A gap is formed between the upper surface,
A common electrode made of a metal plating layer is formed on the lower surface of the lower flexible portion,
The detection circuit detects a force acting on the force receiving body based on capacitance values of a plurality of capacitive elements configured by the individual electrodes and the common electrode. . A power receiving body that receives the force to be detected;
An upper substrate having a columnar body that is formed in a portion of “an upper flexible portion that is thinner than other portions and at least a portion of which is flexible” and extends downward from the center of the upper flexible portion;
A lower substrate in which a “lower flexible part having a smaller thickness than other parts and at least a part of which is flexible” is formed in part;
A plurality of individual electrodes are formed in the detection region on the upper surface, and a detection substrate made of an insulating material;
An apparatus housing to which the lower substrate is fixed;
A detection circuit for detecting a force acting on the force receiving body based on a degree of bending of the lower flexible portion;
With
The upper substrate and the lower substrate are made of a resin material,
The lower end of the columnar body is joined to the center of the upper surface of the lower flexible portion, and the upper substrate is supported above the lower substrate via the columnar body,
The force receiving member is bonded to the upper substrate so as to be positioned above the upper substrate;
The detection substrate is bonded to the lower surface of the lower substrate so that the detection region is located below the lower flexible portion,
The lower flexible portion is formed at a position where the lower surface position of the lower flexible portion is higher than the lower surface position of the lower substrate, and the lower surface of the lower flexible portion and each of the individual electrodes are formed. A gap is formed between the upper surface,
A common electrode made of a metal plating layer is formed on the lower surface of the lower flexible portion,
The detection circuit detects a force acting on the force receiving body based on capacitance values of a plurality of capacitive elements configured by the individual electrodes and the common electrode. . A power receiving body that receives the force to be detected;
An upper substrate on which a “thin flexible portion at least partially flexible with at least a portion being thinner than other portions” is formed;
A lower substrate in which a “lower flexible part having a smaller thickness than other parts and at least a part of which is flexible” is formed in part;
A columnar body having an upper end joined to the center of the lower surface of the upper flexible part and a lower end joined to the center of the upper surface of the lower flexible part;
A plurality of individual electrodes are formed in the detection region on the upper surface, and a detection substrate made of an insulating material;
An apparatus housing to which the lower substrate is fixed;
A detection circuit for detecting a force acting on the force receiving body based on a degree of bending of the lower flexible portion;
With
The upper substrate and the lower substrate are made of a resin material,
The upper substrate is supported above the lower substrate via the columnar body,
The force receiving member is bonded to the upper substrate so as to be positioned above the upper substrate;
The detection substrate is bonded to the lower surface of the lower substrate so that the detection region is located below the lower flexible portion,
The lower flexible portion is formed at a position where the lower surface position of the lower flexible portion is higher than the lower surface position of the lower substrate, and the lower surface of the lower flexible portion and each of the individual electrodes are formed. A gap is formed between the upper surface,
A common electrode made of a metal plating layer is formed on the lower surface of the lower flexible portion,
The detection circuit detects a force acting on the force receiving body based on capacitance values of a plurality of capacitive elements configured by the individual electrodes and the common electrode. . In the force detection device according to any one of claims 1 to 4,
A force detection device, wherein a metal plating layer is also formed on the upper surface of the lower flexible portion. The force detection device according to claim 5,
A force detection device, wherein a metal plating layer is formed on both upper and lower surfaces of the upper flexible portion. The force detection device according to claim 6, wherein
A force detection device, wherein a metal plating layer is formed on substantially the entire surface of an upper substrate and a lower substrate. The force detection device according to claim 7,
A plating notch in which a plating layer is not formed is provided at a connection portion between the upper substrate and the lower substrate, and the plating layer formed on the surface of the upper substrate and the plating layer formed on the surface of the lower substrate are electrically A force detection device characterized by being insulated. In the force detection device according to any one of claims 1 to 8,
A force detection device, wherein the force receiving member is made of a metal material. The force detection device according to claim 9, wherein
A force detection device, wherein the device casing is made of a metal material, and a conductive wire that electrically short-circuits between the force receiving body and the device casing is provided. In the force detection device according to any one of claims 1 to 10,
The detection circuit is provided on the lower surface of the detection substrate,
The force detection device, wherein wiring between each individual electrode formed on the upper surface of the detection substrate and the detection circuit is made through a through hole provided in the detection substrate. The force detection device according to claim 11.
A wiring layer extends from the common electrode formed on the lower surface of the lower flexible portion, and an end of the wiring layer is disposed on the lower surface of the lower substrate,
The detection substrate is joined to the lower surface of the lower substrate by a conductive screw that passes through the through-hole, and the conductive screw passes through an end of the wiring layer, and uses the conductive screw. In addition, a wiring between the common electrode and the detection circuit is provided. In the force detection device according to any one of claims 1 to 12,
A raised portion is formed near the center of the upper surface of the upper flexible portion, and the columnar body or the lower flexible portion is joined by a screw that passes through the raised portion and the upper flexible portion. Force detection device. In the force detection device according to any one of claims 1 to 13,
A plurality of N sets of upper flexible portions are formed on the upper substrate, and a plurality of N sets of lower flexible portions are formed on the lower substrate. And the upper substrate is supported above the lower substrate via a total of N columnar bodies,
A plurality of N sets of detection regions each having a plurality of individual electrodes are provided on the upper surface of the detection substrate, and a common electrode made of a metal plating layer is formed on the lower surface of the plurality of N sets of lower flexible portions. Are formed,
The detection circuit detects a force acting on a force receiving body based on a capacitance value of a capacitive element formed for each of a plurality of N sets of detection regions. In the force detection device according to any one of claims 1 to 14,
A force characterized in that both or one of the upper flexible portion and the lower flexible portion is constituted by a diaphragm that is totally flexible because it is thinner than other portions of the substrate. Detection device. In the force detection device according to any one of claims 1 to 14,
Either or both of the upper flexible portion and the lower flexible portion are constituted by a displacement plate and a beam portion that supports the displacement plate from the periphery, and at least the beam portion is flexible. Force detection device. A power receiving body that receives the force to be detected;
A substrate on which a “flexible portion having a smaller thickness than other portions and at least a portion of which is flexible” is formed in part;
An apparatus housing to which the substrate is fixed;
A force transmission body for transmitting the force received by the force receiving body to the flexible portion;
A detection circuit for detecting a force acting on the force receiving body based on a degree of bending of the flexible portion;
With
The said board | substrate is comprised from the resin material, The metal plating layer is formed in the upper and lower surfaces of the said flexible part, The force detection apparatus characterized by the above-mentioned.