JP6152019B2 - Linear drive unit using ultrasonic motor - Google Patents

Description

  The present invention relates to a linear drive unit using an ultrasonic motor that is applied to a lens barrel or the like of an imaging apparatus that is required to be small and light, high-speed drive, and quiet drive. In particular, the present invention relates to a linear drive unit that requires high stop position accuracy.

  The ultrasonic motor using the ultrasonic vibration of the piezoelectric element has a small size and high driving force, has an excellent feature that it corresponds to a wide speed range, low vibration and low noise. Further, since a frictional force is generated between the vibration part of the ultrasonic motor and the driven body, the force for holding the stopped position of the driven body (hereinafter abbreviated as a holding force) is large even when no current is applied. It also has features. When a linear drive unit is configured using such an ultrasonic motor, the use of two ultrasonic motors has the advantage that the driving force and holding force are approximately doubled compared to the case where one ultrasonic motor is used. .

  The invention of such a linear drive unit is disclosed in Patent Document 1 and Patent Document 2, for example.

  A conventional linear drive unit will be described with reference to FIGS. In the figure, the same members are indicated by the same symbols, and are described using a coordinate system common to the three axes of the X, Y, and Z axes orthogonal to each other.

  FIG. 11 is a diagram showing a configuration of a conventional linear drive unit using two ultrasonic motors. FIG. 11A is a front view, and FIG. 11B is an exploded view showing the state before assembly in FIG. 11A, and is a view seen from the same direction as FIG. 11A.

  FIG. 12 is a front view of a linear drive unit 600 as another configuration of the conventional linear drive unit.

  The linear drive unit 500 includes an upper vibrator 101 and a lower vibrator 102. The upper vibrator 101 has two protrusions 101a and 101b and a piezoelectric element (not shown). The lower vibrator 102 has two protrusions 102a and 102b and a piezoelectric element (not shown). The linear drive unit 500 includes an upper holding member 103, a lower holding member 104, and a support base 106 including an upper support base 106a and a lower support base 106b. The linear drive unit 500 further includes a friction member 108 and a pressure spring 109.

  Similar to the linear drive unit 500, the linear drive unit 600 includes an upper vibrator 201 and a lower vibrator 202 including a piezoelectric element (not shown) and two protrusions. The linear drive unit 600 also has an upper holding member 203 and a lower holding member 204. An upper felt sheet 211 and a lower felt sheet 212 are pasted between the upper vibrator 201 and the upper holding member 203 and between the lower vibrator 202 and the lower holding member 204, respectively. The linear drive unit 600 further includes a support base 106 including an upper support base 106 a and a lower support base 106 b, a friction member 108, and a pressure spring 109, similar to the linear drive unit 500.

  The upper holding member 103 of the linear drive unit 500 holds the upper vibrator 101 in the upper holding portion 103a so as to freely rotate in the direction around the upper holding portion 103a (arrow C). The lower holding member 104 fixes and holds the lower vibrator 102 in a non-rotatable manner in the lower holding portion 104a. The support base 106 supports the upper holding member 103 so that it can be guided in the vertical direction (Z-axis direction) on the upper support base 106a, and fixes and supports the lower holding member 104 on the lower support base 106b. The friction member 108 is provided between the upper vibrator 101 and the lower vibrator 102, and is in contact with the protrusions 101 a and 101 b of the upper vibrator 101 and the protrusions 102 a and 102 b of the lower vibrator 102. The pressure spring 109 has an upper end in contact with the upper support 106a and a lower end in contact with the upper holding member 103, and exerts a pressing force on each.

  The upper holding member 203 of the linear drive unit 600 holds the upper vibrator 201 including the upper felt sheet 211 in the upper holding portion 203a. The lower holding member 204 fixes and holds the lower vibrator 202 including the lower felt sheet 212 in a non-rotatable manner. The support base 106 supports the upper holding member 203 so that it can be guided in the vertical direction (Z-axis direction) on the upper support base 106a, and fixes the lower holding member 204 via the lower felt sheet 212 on the lower support base 106b. And support. Similar to the linear drive device 500, the friction member 108 is provided between the upper vibrator 201 and the lower vibrator 202, and is in contact with the protrusions 101a and 101b and the protrusions 102a and 102b. The pressure spring 109 has an upper end in contact with the upper support 106a and a lower end in contact with the upper holding member 203, and exerts a pressing force on each.

Next, the operation of the conventional linear drive unit will be described.
The support base 106 of the linear drive unit 500 is fixed to a fixed portion (not shown) and is on the fixed side. On the other hand, the friction member 108 is movable because it can move relative to the support 106. Due to the pressing force of the pressure spring 109, the upper vibrator 101 and the upper holding member 103 are pressed against the lower vibrator 102 fixed via the friction member 108, and the upper vibrator 101 and the lower vibrator 102 are in friction. A frictional force is generated on the contact surface with the member 108. By applying a high-frequency AC voltage from a power supply unit (not shown), the upper vibrator 101 and the lower vibrator 102 are ultrasonically vibrated. The friction member 108 linearly drives the support base 106 in the X-axis direction by the frictional force between the upper vibrator 101 and the lower vibrator 102 and the friction member 108. The linear drive is transmitted to the outside by the drive connection unit 108a. The upper vibrator 101 is held by the upper holding member 103 at the center, and the lower vibrator 102 is held by the lower holding member 104 at the center. The center is a portion corresponding to a node of ultrasonic vibration of each vibrator. Therefore, the maximum driving force is obtained without hindering the vibration of the ultrasonic vibration. When the high-frequency AC voltage is not energized, the stop position of the friction member 108 relative to the support base 106 is held due to the influence of the frictional force. As described above, the use of two vibrators has approximately twice the driving force and holding force as compared with the case of using one vibrator.

  On the other hand, in the linear drive unit 600, the support 106 is on the fixed side, and the friction member 108 is on the movable side, and has the same action as the linear drive unit 500. Therefore, the friction member 108 can be moved relative to the support base 106. With regard to this structure, the vibration is also inhibited by sticking a felt sheet made of a material having a small amount of vibration medium and having a low effect of attenuating and suppressing vibration to the back surface of the vibrator, and holding and pressing the felt sheet. The maximum driving force can be obtained without any problems.

JP 2005-31264 A JP 2006-67712 A

  Generally, in a linear drive unit, a first requirement for obtaining the maximum driving force and a second requirement for increasing the stop position accuracy are necessary.

  The first requirement for obtaining the maximum driving force is to generate sufficient frictional force between the protrusion of the oscillator and the friction member, so that the oscillator can move freely in the direction of the pressing force of the pressure spring. In order to obtain a large vibration of the vibrator, the vibration of the vibrator is not inhibited. The second requirement for making the stop position accuracy high is that the mechanical response delay element in the moving direction on the movable side is sufficiently small with respect to the target stop position accuracy.

  However, the conventional linear drive units disclosed in Patent Document 1 and Patent Document 2 described above have the following problems.

  In the linear drive unit 500, the lower vibrator 102 is fixed to the lower support base 106 b via the lower holding member 104. However, the upper vibrator 101 is rotatably supported by the upper support base 106 a via the upper holding member 103. Therefore, a mechanical delay is caused by the gap necessary for the rotatable support. Here, in order not to disturb the free movement of the upper vibrator 101 in the pressurizing direction, the gap needs to be about several μm. A gap of about several μm causes a large mechanical response delay when the target stop position accuracy is, for example, several μm or less, and does not satisfy the second requirement described above.

  Further, in the linear drive unit 600, the mechanical response delay element is the same as that of the linear drive unit 500 because the upper vibrator 201 is rotatably supported by the upper support base 106a via the upper holding member 203. Not only the necessary gap, but also deformation of the upper felt sheet 211 in the shearing direction is added. Then, when the target stop position accuracy is set to, for example, several μm or less, it causes a large mechanical response delay and does not satisfy the second requirement described above for the linear drive unit 500 or more.

  As described above, both the upper vibrator 101 of the linear drive unit 500 and the upper vibrator 201 of the linear drive unit 600 are supported rotatably with respect to the upper support base. Therefore, it has a large mechanical response delay element with respect to the target stop position accuracy.

  On the other hand, when the gap for the upper vibrator 201 to be rotatably supported by the upper support base via the upper holding member is set to a sufficiently small amount, the direction of the pressing force of the pressure spring in the upper vibrator 201 is reduced. Inhibits free movement. As a result, the first requirement is not satisfied.

  As described above, in the conventional linear drive unit, the stop position accuracy with respect to the target stop position accuracy without hindering the free movement of the upper vibrator 201 and the vibration of the upper vibrator 201 in the direction of the pressing force of the pressure spring. There was a problem that could not be made highly accurate.

  In order to solve the above problems, a linear drive unit of the present invention includes two vibrators that generate high-frequency vibrations, a first holding member that holds one vibrator of the two vibrators, and the one A second holding member for holding the other vibrator of the two vibrators so as to face the vibrator, a connecting member for connecting the first holding member and the second holding member, and the first A support shaft extending through part of one holding member and the second holding member, wherein the first holding member and the second holding member are arranged around an axis of the support shaft. A support shaft that is rotatably supported, a pressure member that applies a pressing force in a direction in which the two vibrators approach each other, and extends in the extending direction of the support shaft, and is sandwiched between the two vibrators. A friction member, and the high frequency vibration causes the two vibrators and the friction member to be One is to move between the said extending direction relative to the other of said connecting member is characterized by having a displacement hardly rigidity to the extending direction than in the direction perpendicular to the extending direction.

  The stop position accuracy can be made high without obstructing the free movement of the vibrator in the direction of the pressing force of the pressure spring and the vibration of the vibrator between the fixed side and the movable side by the above means. A linear drive unit can be provided.

It is a linear drive unit which concerns on Example 1 of this invention, Comprising: It is a figure explaining the structure by which a friction member is driven. It is a figure explaining the state of the connection by the connection member of the linear drive unit which concerns on Example 1 of this invention. It is a linear drive unit which concerns on Example 1 of this invention, Comprising: It is a figure explaining the case where the connection state of FIG. 2 is decomposed | disassembled. It is a linear drive unit which concerns on Example 1 of this invention, Comprising: It is a figure explaining the structure by which a vibrator | oscillator is driven. It is a linear drive unit which concerns on Example 1 of this invention, Comprising: It is a figure explaining the structure by which a felt sheet is added to a vibrator | oscillator and a friction member is driven. It is a linear drive unit which concerns on Example 1 of this invention, Comprising: It is a figure explaining the structure by which a felt sheet is added to a vibrator | oscillator and a vibrator | oscillator is driven. It is a figure explaining operation | movement of the holding member of the linear drive unit by this invention. It is a figure explaining the structure of the linear drive unit of Example 2 of this invention. It is a figure explaining the structure of the linear drive unit of Example 3 of this invention. It is a figure explaining the structure of the linear drive unit of Example 4 of this invention. It is a figure explaining the structure of the linear drive unit of the conventional Example. It is a figure explaining the structure of the linear drive unit of another conventional Example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the figure, the same member is indicated by the same symbol, and the common axis is the X axis in the relative movement direction between the upper vibrator and the lower vibrator and the friction member, and the direction of the pressing force of the pressure spring. The Y axis is set and used in a direction perpendicular to the Z axis, the X axis, and the Z axis. However, the X, Y, and Z axes are set for easy understanding in the drawings, and do not limit the present invention.

  A first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a linear drive unit of this embodiment using two ultrasonic motors, and shows a configuration in which a friction member is driven. 1A is a plan view, FIG. 1B is an aa cross-sectional view of FIG. 1A, and FIG. 1C is a bb cross-sectional view of FIG. 1B. FIG. 2 shows a state of connection by a connecting member of the linear drive unit. FIG. 3 shows a state where the connected state of FIG. 2 is disassembled. 3A is a perspective view of the connecting member, FIG. 3B is a perspective view of the upper holding member, and FIG. 3C is a perspective view of the lower holding member. FIG. 4 shows a configuration in which the vibrator is driven in the linear drive unit of this embodiment. 4A is a plan view, FIG. 4B is a cc cross-sectional view of FIG. 4A, and FIG. 4C is a dd cross-sectional view of FIG. 4B. FIG. 5 shows a configuration in which a felt sheet is added to the vibrator and the friction member is driven in the linear drive unit of this embodiment. 5A is a plan view, FIG. 5B is an ee sectional view of FIG. 5A, and FIG. 5C is an ff sectional view of FIG. 5B. FIG. 6 shows a configuration in which a felt sheet is added to the vibrator and the vibrator is driven in the linear drive unit of this embodiment. 6A is a plan view, FIG. 6B is a gg cross-sectional view of FIG. 6A, and FIG. 6C is a hh cross-sectional view of FIG. 6B.

  The linear drive unit 100 of this embodiment includes two vibrators, an upper vibrator 1 and a lower vibrator 2, an upper holding member 3 as a first holding member, and a lower holding as a second holding member. Member 4. The linear drive unit 100 further includes a connecting member 5, a guide shaft 7 as a support shaft, a pressure spring 9 as a pressure member, and a friction member 8.

  The upper vibrator 1 of one of the two vibrators and the lower vibrator 2 of the other vibrator face each other, and each have two protrusions 1a and 1b and protrusions 2a and 2b. The upper vibrator 1 and the lower vibrator 2 are further composed of unillustrated piezoelectric elements, and generate high-frequency vibrations. The upper holding member 3 holds the upper vibrator 1 in a non-rotatable manner via the upper holding portion 3a. The lower holding member 4 fixes and holds the lower vibrator 4 via the lower holding portion 4a. The upper holding member 3 and the lower holding member 4 are connected by a connecting member 5. The guide shaft 7 is provided on the support base 6, and the upper holding member 3 and the lower holding member 4 are supported so as to be rotatable around the axis of the guide shaft 7. The linear drive unit 100 further includes a spring pressing member 10 having an upper surface portion, a lower surface portion, and a side surface portion connecting one end portion of the upper surface portion and one end portion of the lower surface portion. The pressure spring 9 has a lower end in contact with the upper holding member 3 and an upper end in contact with the inner side of the upper surface portion of the spring pressing member 10. Therefore, the pressurizing spring 9 is sandwiched between the upper holding member 3 and the spring pressing member 10 and applies a pressing force to each. The lower holding member 4 is in contact with the inside of the lower surface portion of the spring pressing member 10. The pressing force applied to the upper surface portion of the spring pressing member 10 by the pressure spring 9 is also transmitted to the lower surface portion through the side surface portion. As a result, a pressing force by the pressure spring 9 is also applied to the lower holding member 4. In the present embodiment, the pressurizing means is constituted by the pressurizing spring 9 and the spring pressing member 10. The support base 6 is fixed to a fixed portion (not shown) and supports the friction member 8 so as to be movable. The friction member 8 is a rod-like object extending in the extending direction of the guide shaft. The friction member 8 has a drive connection portion 8 a and is sandwiched between the upper vibrator 1 and the lower vibrator 2. Then, due to a predetermined pressing force by the pressure spring 9, the upper vibrator 1 and the lower vibrator 2 are pressed in the direction of the friction member 8, that is, the direction in which the upper vibrator 1 and the lower vibrator 2 approach each other. Is done.

  Next, the structure of the connection between the upper holding member 3 and the lower holding member 4 and the connecting member 5 will be described with reference to FIGS. In FIG. 2, parts other than the upper holding member 3, the lower holding member 4, the connecting member 5, and the support base 6 are omitted for clarity of illustration. 3B and 3C, the portions other than the upper holding member 3 and the lower holding member 4 are omitted for the sake of clarity.

  The connecting member 5 includes XY bendable surfaces 51, 52, 53, and 54 that are parallel to the XY plane, an XZ bendable surface 55 that is parallel to the XZ plane, and screw holes 5a, 5b, 5c, and 5d. 5e. The XZ bendable surface 55 further has a notch in the X-axis direction.

  The upper holding member 3 includes an upper surface portion 31, an upper center rib 32 having a protruding portion, and an upper right side rib 33. The lower holding member 4 includes a bottom surface portion 41, a lower left rib 42 having a lower left protruding rib 43, a lower center rib 44, and a lower right protruding rib 45.

  In the connecting member 5, the XY bendable surfaces 51, 52, 53, 54 are bent at the four corners around the screw hole 5 c and the XZ bendable surface 55 in which the notches are arranged on both sides thereof, and are integrally connected. Has been. Screw holes 5a, 5b, 5d, and 5e are provided at the end of the XY bendable surface 51, the end of the XY bendable surface 52, the end of the XY bendable surface 53, and the end of the XY bendable surface 54, respectively. It has been.

  Each rib of the upper holding member and each rib of the lower holding member are arranged at the same end in the Y-axis direction in each of the upper surface portion 31 and the bottom surface portion 41. The upper center rib 32 has a round hole 3b through which the guide shaft 7 is inserted in the X-axis direction, and a screw hole 3c in a protruding portion that protrudes outward in the Y-axis direction. The upper right rib 33 is provided with a long hole 3d that penetrates the guide shaft 7 in the X-axis direction. The lower left rib 42 is provided with a long hole 4b through which the guide shaft 7 is inserted in the X-axis direction. The lower left protruding rib 43 protruding outward in the Y-axis direction from the lower left rib 42 is provided with a screw hole 4c on the upper side in the Z axis direction. The lower center rib 44 is provided with a penetrating round hole 4d for inserting the guide shaft 7 in the X-axis direction. The lower right protruding rib 45 has a screw hole 4e on the upper side in the Z-axis direction.

  The screw hole 5c of the connecting member 5 and the screw hole 3c of the upper holding member 3 are fastened by screws 11c. The screw hole 5d of the connecting member 5 and the screw hole 4c of the lower holding member 4 are fastened by a screw 11d. The screw hole 5e of the connecting member 5 and the screw hole 4e of the lower holding member 4 are fastened by a screw 11e.

  The upper holding member 3 and the lower holding member 4 are connected to each other via the connecting member 5 by fastening with screws as described above. In the first embodiment, the friction member 8 moves with respect to the upper vibrator 1 and the lower vibrator 2, that is, the upper vibrator 1 and the lower vibrator 2 do not move. Therefore, the connecting member 5 is fastened to the support base 6 by screws 11a and 11b through screw holes 5a and 5b, respectively. The linear drive generated by the friction member 8 is transmitted to the outside by the drive connection portion 8a.

  In addition, although the fixing method by screwing was adopted in the present embodiment, the same effect can be obtained not only by screwing but also by methods such as welding, adhesion, and insert molding.

  A guide shaft 7 (not shown) is inserted in the X-axis direction along the dashed line in the figure into the elongated holes 4b and 4d of the lower holding member 4 and the round holes 3b and 3d of the upper holding member 3. Is done. Then, both ends of the guide shaft 7 are fixed to the support base. Therefore, the upper holding member 3 and the lower holding member 4 are guided along the guide shaft 7 in the X-axis direction, which is the relative movement direction of the upper holding member and the lower holding member 4 and the friction member. Here, the combination of the round hole 3b and the long hole 3d of the upper holding member 3 and the combination of the round hole 4d and the long hole 4b of the lower holding member 4 function as a guide portion. In addition, even if a round hole is a long hole in the combination of each guide part, the intersection part of the adjacent long hole between the upper side holding member 3 and the lower side holding member 4 can be made into a round hole.

  Next, with reference to FIG. 4, the linear drive unit 200 when the friction member 8 is a fixed side and the upper vibrator 1 and the lower vibrator 2 are movable with respect to the linear drive unit 100 in this embodiment will be described. To do.

  The linear drive unit 200 has the same structure as the linear drive unit 100. The connecting member 5 of the linear drive unit 200 is connected to the upper holding member 3 and the lower holding member 4 in the same manner as the linear drive unit 100, but does not have any fastening with the support base 6. The friction member 8 is provided between the upper vibrator 1 and the lower vibrator 2, and both ends thereof are fixed to the support base 6. In the linear drive unit 200, unlike the linear drive unit 100, the friction member 8 is on the fixed side, and the upper vibrator 1 and the lower vibrator 2 are on the movable side. Therefore, linear drive can be taken out by connecting a driven body (not shown) to the connecting member 5 part.

  Next, with reference to FIG. 5, a linear drive unit 300 having the same structure as that of the linear drive unit 100 in the present embodiment but having different configurations of the upper vibrator 1 and the lower vibrator 2 will be described.

  In the linear drive unit 300, like the linear drive unit 100, the upper vibrator 1 and the lower vibrator 2 are the fixed side, and the friction member 8 is the movable side. The linear drive unit 300 has an upper felt sheet 25 and a lower side having the same effects as those of the prior art on the back surface of the surface on which the protrusions of the upper vibrator 1 and the lower vibrator 2 are arranged with respect to the linear drive unit 100. A felt sheet 26 is attached. And it is pressurized by the pressure spring 9 through the upper pressure plate 27 and the lower pressure plate 28, respectively. Therefore, only the end portions of the upper vibrator 1 and the lower vibrator 2 are fixed to the upper holding member 3 and the lower holding member 4. In the linear drive unit 300, the upper holding part 3a and the lower holding part 4a of the linear drive unit 100 are not present.

  Next, with reference to FIG. 6, a linear drive unit 400 having the same structure as that of the linear drive unit 200 in this embodiment but having different configurations of the upper vibrator 1 and the lower vibrator 2 will be described.

  In the linear drive unit 400, like the linear drive unit 200, the friction member 8 is on the fixed side, and the upper vibrator 1 and the lower vibrator 2 are on the movable side. The linear drive unit 400 has an upper felt sheet 25 and a lower side having the same effects as those of the prior art on the back surface of the surface on which the protrusions of the upper vibrator 1 and the lower vibrator 2 are arranged with respect to the linear drive unit 200. A felt sheet 26 is attached. The pressure spring 9 is pressurized via the upper pressure plate 27 and the lower pressure plate 28. Therefore, only the end portions of the upper vibrator 1 and the lower vibrator 2 are fixed to the upper holding member 3 and the lower holding member 4. In the linear drive unit 400, the upper holding part 3a and the lower holding part 4a of the linear drive unit 200 are not present. Further, the holding member 5 of the linear drive unit 400 connects the upper holding member 3 and the lower holding member 4 by the same connection method as the linear drive unit 100, but has a fastening with the support base 6. Absent. The friction member 8 is provided between the upper vibrator 1 and the lower vibrator 2, and both ends thereof are fixed to the support base 6. In addition, the linear drive unit 400 can take out the linear drive by connecting a driven body (not shown) to the connecting member 5.

Next, operations and effects of the present embodiment will be described with reference to FIG.
FIG. 7 shows the linear drive unit 100 as a representative. However, the linear drive units 200, 300, and 400 have the same effect. Further, parts other than the upper support member 3, the lower support member 4, the connecting member 5, and the support base 6 are omitted for the sake of clarity.

  In this embodiment, the upper vibrator 1 and the lower vibrator 2 are pressed against the friction member 8 through the upper holding member 3 and the lower holding member 4 by the pressing force applied by the pressure spring 9. Touched. That is, the upper vibrator 1 and the lower vibrator 2 are pressed by the pressurizing spring 9 in a direction approaching each other. Therefore, a frictional force is generated on the contact surface between the upper vibrator 1 and the lower vibrator 2 and the friction member 8. A high frequency AC voltage is applied from a power supply means (not shown), and the upper vibrator 1 and the lower vibrator 2 generate ultrasonic vibrations. The frictional force causes relative movement between the upper vibrator 1 and the lower vibrator 2 and the friction member 8 to generate linear drive in the X-axis direction.

  The guide shaft 7 (not shown) is formed into the long hole 4b and the round hole 4d of the lower holding member 4, the round hole 3b and the long hole 3d of the upper holding member 3, and the axis of the guide shaft 7 is a one-dot chain line in the figure. It is inserted in the X-axis direction so as to be along. Therefore, the upper holding member 3 and the lower holding member 4 are swingable (rotatable) in the rotation direction of the arrow A around the axis of the guide shaft 7 parallel to the X axis. Further, there are gaps between the guide shaft 7, the long holes 4 b and the round holes 4 d of the lower holding member 4, and the round holes 3 b and the long holes 3 d of the upper holding member 3. Therefore, at the position of the screw 5c, the upper holding member 3 and the lower holding member 4 have the X axis that is the relative movement direction between the upper vibrator 1, the lower vibrator 2, and the friction member 8, and the pressure spring. 9 is swingable (rotatable) in the rotation direction of arrow B about the Y axis perpendicular to the Z axis which is the direction of the pressing force 9. And in the case of the linear drive unit 100 and the linear drive unit 300, the friction member 8 moves to the X-axis direction of a figure, and a linear drive is generate | occur | produced. In the case of the linear drive unit 200 and the linear drive unit 400, the upper vibrator 1 and the lower vibrator 2 move in the X-axis direction to generate linear drive.

  In addition, since the frictional force of the two vibrators acts at the time of driving to which the high-frequency AC voltage is applied and at the time of stopping when the voltage is not applied, the driving force is approximately twice that of the case of one vibrator. And generate a holding force.

  In the present embodiment, the pressure spring 8 is assumed to be a compression spring, but the same effect can be obtained even if a tension spring that directly connects the upper holding member 3 and the lower holding member 4 is employed.

  In the connecting member 5, XY bendable surfaces 51, 52, 53, 54 and an XZ bendable surface 55, which are bendable and deformable surfaces, are parallel to the X axis. In other words, all the bending-deformable surfaces are parallel to the X axis that is the traveling direction of the vibrator. Therefore, even if the upper vibrator 1 and the lower vibrator 2 are displaced in the X-axis direction, the connecting member 5 is an elastic body, and the amount of bending deformation is mainly small due to tensile deformation, compression deformation, and the like. . Therefore, the connecting member 5 has a large bending rigidity with respect to displacement in the X-axis direction, and has a cross-sectional shape for maintaining the bending rigidity. That is, the deformation amount of the connecting member 5 can be made sufficiently small even when the target stop position accuracy is set to several μm or less, for example. As a result, the linear drive unit of the present embodiment can satisfy the requirement for increasing the stop position accuracy that the mechanical response delay element in the traveling direction is sufficiently small with respect to the target stop position accuracy. Further, in the connecting member 5, the XY bendable surfaces 51, 52, 53, 54 and the XZ bendable surface 55 are not parallel to each other. That is, at least two of the two or more bendable surfaces are not parallel to each other. As a result, even if the upper vibrator 1 and the lower vibrator 2 are displaced in the Y-axis direction or the Z-axis direction, the connecting member 5 has the XY bendable surfaces 51, 52, 53, 54 or the XZ bendable surface 55. Can be bent and deformed. Accordingly, the connecting member 5 has a small rigidity against displacement in the Y-axis direction and the Z-axis direction orthogonal to the X-axis direction. That is, the rigidity of the connecting member 5 is small with respect to the pressing force of the pressure spring 9. As a result, the linear drive unit of the present embodiment does not inhibit the free movement of the vibrator in the pressurizing direction in order to generate a sufficient frictional force, and does not inhibit the vibration of the vibrator in order to obtain a large vibration. Can meet the requirements to get maximum driving force.

  In the present embodiment, the upper holding member 3 and the lower holding member 4 holding the upper vibrator 1 and the lower vibrator 2 are provided at positions close to each other around the guide shaft 7, so that the stop position The upper vibrator 1 and the lower vibrator 2 can be coupled so as to satisfy the requirements for achieving high accuracy and the requirements for obtaining the maximum driving force at the same time.

  As described above, the linear drive unit of the present embodiment has a sufficiently small mechanical response delay element in the traveling direction with respect to the target stop position accuracy, and can make the stop position accuracy highly accurate.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the first embodiment, all of the bending deformable surfaces are parallel to the X-axis that is the traveling direction of the vibrator, and at least two of the bending deformable surfaces are not parallel to each other. .

  In the present embodiment, a connecting member having another shape that satisfies these characteristics of the first embodiment is used.

  FIG. 8 is a diagram for explaining a state of connection by the connecting member of the linear drive unit according to the second embodiment of the present invention.

  In the present embodiment, the upper holding member 3 is common to the first embodiment. The lower holding member 4 </ b> A includes a bottom surface portion 41, a lower left rib 42, and a lower center rib 44 having a lower center protruding rib 46. The lower center protruding rib 46 has a screw hole 4f on the upper side in the Z-axis direction.

  The connecting member 5A includes XY bendable surfaces 51, 52, and 56 that are parallel to the XY plane, an XZ bendable surface 55 that is parallel to the XZ plane, and screw holes 5a, 5b, and 5f. . The XZ bendable surface 55 further has a notch in the X-axis direction.

  In the connecting member 5A, the XY bendable surfaces 51 and 52 are bent at the two upper corners around the XZ bendable surface 55 and are integrally connected. Further, at the two lower corners, the XY bendable surface 56 is bent and connected integrally. Screw holes 5a, 5b, and 5f are provided in the middle of the end of the XY bendable surface 51, the end of the XY bendable surface 52, and the XY bendable surface 54, respectively.

  The screw holes 5a, 5b, and 5c of the connecting member 5A are used for fastening screws with the upper holding member 3 in the same configuration as in the first embodiment. The screw hole 5f of the connecting member 5A is used for screw fastening with the screw hole 4f of the lower holding member 4A.

  Also in the connecting member 5A, the XY bendable surfaces 51, 52, 56 and the XZ bendable surface 55 are parallel to the advancing direction (X-axis direction) of the vibrator and are not parallel to each other. Therefore, the connecting member 5A of the present embodiment satisfies the requirements of the connecting member 5 of the first embodiment. Further, the same effect can be obtained even if the connecting member is a string-like wire having tension in the traveling direction.

  Next, Embodiment 3 of the present invention will be described with reference to FIG.

  FIG. 9 is a view for explaining a state of connection by the connecting member of the linear drive unit according to the third embodiment of the present invention.

  In the present embodiment, the upper holding member 3 and the lower holding member 4 are common to the first embodiment.

  The connecting member 5B includes XY bendable surfaces 51, 52, 57, 58 that coincide with the XY plane, an XZ bendable surface 55 having a surface parallel to the XZ plane, screw holes 5a, 5b, 5c, 5d, and 5e. Is provided. The XZ bendable surface 55 further has a notch in the X-axis direction.

  In the connecting member 5 </ b> B of this embodiment, the XY bendable surface 57 corresponds to the XY bendable surface 53 of the connecting member 5, and the XY bendable surface 58 corresponds to the XY bendable surface 54 of the connecting member 5. However, the XY bendable surface 57 includes a step having a surface parallel to the YZ plane, and the XY bendable surface 58 includes a step having a surface parallel to the YZ plane.

  The configuration of the connecting member 5B according to the present embodiment does not satisfy the feature of the connecting member 5 that all of the bending-deformable surfaces are parallel to the X axis that is the traveling direction of the vibrator.

  Even if the connecting member 5B does not necessarily satisfy this feature, the rigidity with respect to the force for displacing the upper holding member 3 and the lower holding member 4 in the X-axis direction is sufficiently large, and the rigidity for displacing in the direction orthogonal to the X-axis direction is sufficient. If it is small, the same effect as in the first embodiment can be obtained.

  That is, the connecting member 5B has a feature that a step having a plane parallel to the YZ plane is not parallel to the traveling direction of the vibrator, and therefore all the bending-deformable surfaces are parallel to the X axis that is the traveling direction of the vibrator. Does not meet. However, if the surface of the step is sufficiently small, the rigidity to be displaced in the X-axis direction is large, and the amount of deformation is sufficiently small with respect to the target stop position accuracy, the same effect as in the first embodiment can be obtained. .

Next, a fourth embodiment of the present invention will be described with reference to FIG.
FIG. 10 is a view for explaining a state of connection by the connecting member of the linear drive unit according to the fourth embodiment of the present invention.

  In the present embodiment, the upper holding member 3 is common to the first embodiment. The lower holding member 4B includes a bottom surface portion 41, a left lower rib 42 having a protruding portion protruding outward in the Y-axis direction, a lower center rib 44, and a right having a protruding portion protruding outward in the Y-axis direction. A lower rib 47. The protrusion of the lower left rib 42 is provided with a screw hole 4g, and the protrusion of the lower right rib 47 is provided with a screw hole 4h.

  The connecting member 5C includes an XZ bendable surface 59 that is a surface parallel to the XZ plane and has a linear shape in the X-axis direction, and screw holes 5c, 5g, 5h, 5i, and 5j. The XZ bendable surface 59 has a width W in the Z-axis direction.

  The screw hole 5c of the connecting member 5C is used for fastening the screw with the upper holding member 3 with the same configuration as in the first embodiment. The screw hole 5h of the connecting member 5C is used to fasten the screw with the screw hole 4g of the lower holding member 4B. The screw hole 5i is used to fasten the screw with the screw hole 4h of the lower holding member 4B. The screw holes 5g and 5j of the connecting member 5C are used to fasten the screws to the support base when the upper vibrator and the lower vibrator are on the fixed side.

  Since the configuration of the connecting member 5C of the present embodiment is configured by only one bending deformable surface parallel to the XZ plane, at least two of the two or more bending deformable surfaces are not parallel to each other. The characteristics of the connecting member 5 are not satisfied.

  However, even if the connecting member 5C does not necessarily satisfy this characteristic, if the width W of the connecting member 5C is small in the operation of the linear drive unit in the X-axis direction and the load displaced in the Y-axis direction is sufficiently small, the first embodiment will be described. The same effect can be obtained.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  The linear drive unit of the present invention can be used for a lens barrel of an image pickup apparatus that is required to be small, light, and driven at high speed, particularly a moving image-compatible lens barrel that requires stop position accuracy.

Reference Signs List 1 upper vibrator 2 lower vibrator 3 upper holding member 4 lower holding member 4A lower holding member 4B lower holding member 5 connecting member 5A connecting member 5B connecting member 5C connecting member 6 support base 7 guide shaft 8 friction member 9 Pressure spring

Claims (7)

Two vibrators that generate high-frequency vibrations;
A first holding member for holding one of the two vibrators;
A second holding member that holds the other vibrator of the two vibrators so as to face the one vibrator;
A connecting member that connects the first holding member and the second holding member;
A support shaft extending through a part of the first holding member and the second holding member, wherein the first holding member and the second holding member are axial centers of the support shafts. A support shaft that rotatably supports around,
A pressing member that applies a pressing force in a direction in which the two vibrators approach each other;
A friction member extending in the extending direction of the support shaft and sandwiched between the two vibrators;
Have
By the high frequency vibration, one of the two vibrators and the friction member moves in the extending direction with respect to the other,
The linear drive unit characterized in that the connecting member has rigidity that is less likely to be displaced in the extending direction than in a direction orthogonal to the extending direction.   Each of the first holding member and the second holding member has a guide portion through which the support shaft passes to support the first holding member and the second holding member, The holding member and the second holding member are capable of swinging about the axis and swinging about an axis perpendicular to the direction of the pressing force and the extending direction. The linear drive unit according to claim 1.   3. The linear drive unit according to claim 2, wherein the connecting member includes a surface that extends in the extending direction and can be bent and deformed in a direction orthogonal to the extending direction. The connecting member further includes one or more bending deformable surfaces,
The linear drive unit according to claim 3, wherein at least two of all the bending deformable surfaces are not parallel to each other.   Of the one or more bending deformable surfaces, at least one bending deformable surface has a shape that can easily bend in the direction of swinging around the axis or swinging around the vertical axis. The linear drive unit according to claim 4. A support member for fixing the connecting member and the support shaft;
The linear drive unit according to claim 1, wherein the movement in the extending direction is such that the friction member moves with respect to the two vibrators. A support member for fixing the friction member and the support shaft;
The linear drive unit according to claim 1, wherein the movement in the extending direction is such that the two vibrators move relative to the friction member.

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