JPH0636660A - pressure switch - Google Patents

Abstract

(57) [Summary] [Purpose] To realize a compact pressure switch and improve reliability. [Constitution] The pressure of the fluid acts on the upper end surface of the piston 16. As a result, a pressing force defined by the product of the fluid pressure and the area of the upper end surface of the piston 16 is applied to the upper end surface of the piston 16. This pressing force is applied to the center of the snap action disc 24 from the piston rod 16a via the piston 16. When the fluid pressure increases and reaches the set value, the pressing force applied from the piston 16 to the snap action disk 24 reaches a predetermined value, that is, the snap operation point, and the snap action disk 2
4 is properly reversed and displaced from the first position to the second position,
As a result, the snap action disk 24 and the contact 30 are brought into pressure contact with each other at an appropriate pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure switch that opens and closes or switches according to changes in pressure.

[0002]

2. Description of the Related Art In the advanced field of pneumatic systems and hydraulic systems, development of compact, long-life and highly reliable high-pressure operation type pressure switches has been awaited. For example, in recent automatic braking and power steering systems, high-pressure operation type pressure regulators that are compact and lightweight to improve fuel efficiency and maintain high reliability for a long period of time in terms of safety improvement A switch is required.

In a typical conventional pressure switch, a flexible diaphragm is displaced according to a fluid pressure, and the switch is switched by the displacement of the diaphragm. Further, as another type, there is one in which the peripheral portion of the disc is fixed by welding or the like, and the central portion of the disc is displaced to one side according to the pressure difference between both sides of the disc, and the switch is switched by the disc displacement. .

[0004]

However, the conventional pressure switch as described above normally operates for a relatively low fluid pressure of about 35 to 70 kg / cm ² , but a higher pressure, for example, 100 or more. Sufficient reliability could not be guaranteed for a high pressure of about 200 kg / cm ² . Further, in the conventional pressure switch, when the fluid pressure is high, the load applied to the diaphragm or the disk becomes very large, so that the member or casing supporting the diaphragm or the disk has to be large and thick.

It is also possible to operate the diaphragm with a high fluid pressure by applying a ring-shaped support plate to the diaphragm and limiting the displacing portion of the diaphragm to the center of the diaphragm facing the central opening of the ring-shaped support plate. Has been done. However, in this configuration, when the diaphragm is displaced, a large local stress is applied to the diaphragm at the edge of the central opening of the ring-shaped support plate, so that the diaphragm is easily worn or damaged, and the switch life is shortened. is there.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a high-pressure operation type pressure switch which ensures a highly reliable switch operation with a small size and a simple structure.

[0007]

To achieve the above object, a first pressure switch of the present invention is arranged in a space formed in communication with a fluid passage and is movable in response to fluid pressure. A piston member, a piston guide member that is disposed in the space and guides the piston member, a displacement member that displaces from the first position to the second position in response to movement of the piston member, and first and second And a switch member that electrically connects or disconnects the first conductive member and the second conductive member in response to the displacement of the displacement member. .

Further, a second pressure switch of the present invention is, in the first pressure switch, for adjusting a pressurizing moment applied from the piston member to the displacement member between the piston member and the displacement member. The converter member is provided.

A third pressure switch of the present invention is the same as the first pressure switch, wherein a diaphragm is provided between the piston member and the displacement member, and the piston member side and the displacement member side are fluidized. With respect to the above, the configuration is cut off.

Further, a fourth pressure switch of the present invention is such that one end face of the piston member receives fluid pressure, piston guide means for guiding the piston member, and the other end face of the piston member facing each other. The snap action disc that is disposed and that is displaced from the first disc position to the second disc position when the pressing force from the piston member becomes equal to or greater than a first predetermined value; Means for urging the disk position from the disk position toward the first disk position, and when the pressing force from the piston member becomes equal to or less than a second predetermined value, the spring means is displaced from the first spring position to the second spring position. It is configured to have a spring.

[0011]

In the first pressure switch of the present invention, the pressure of the fluid acts on one end face of the piston member, so that the pressing force or the pressing force corresponding to the product of the fluid pressure and the area of the one end face of the piston member is applied. The pressing force is applied to the displacement member from the other end surface of the piston member. When the pressing force from the piston member reaches the snap action point of the displacement member, the displacement member is reversely displaced from the first position to the second position. The displacement of the displacement member can be used to move the movable contact to connect or disconnect the fixed contact. After the displacement member is displaced to the second position, when the fluid pressure decreases and the pressing force from the piston member decreases to the snap action point of the displacement member, the displacement member is moved to the second position by the repulsive force or the restoring force from the spring means. The position is inverted from the position to the first position.

In the second pressure switch of the present invention, the converter member moves the operating point of the pressing force applied to the displacing member, for example, the operating point in the radial direction of the disk to the outer peripheral side of the disk, thereby pressing the displacing member. The moment can be reduced, which makes it possible to convert the fluid pressure into a smaller piston driving force.

In the third pressure switch of the present invention, when the piston member moves according to the fluid pressure, the diaphragm deforms or displaces in a manner that follows, and the pressing force from the piston member side is transmitted to the displacement member, or Repulsive force from the displacement member side is transmitted to the piston member side. However, regarding the fluid, the diaphragm blocks the piston member side and the displacement member side. As a result, even if fluid, especially liquid, leaks on the piston member side, the leaked fluid does not reach the displacement member or the contact portion.

In the fourth pressure switch of the present invention, when the pressing force from the piston member is greater than or equal to the second predetermined value and less than or equal to the first predetermined value, the snap action disk and the coned spring are each set to the first pressure value. Disc position and first
Stays in the spring position, and in this state the first switch state,
For example, a switch closed state can be created. When the pressing force from the piston member falls below the second predetermined value,
The displacement of the countersunk spring from the first spring position to the second spring position can form a first switch state, for example a switch closed state. When the pressing force from the piston member exceeds the first predetermined value, the snap action disc is displaced from the first disc position to the second disc position, thereby causing the first switch state, that is, the switch closing. A state can be formed.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 are cross-sectional views showing the structure of the pressure switch according to the first embodiment. FIG. 1 shows the switch open state and FIG. 2 shows the switch closed state.

The casing of this pressure switch comprises an upper casing 10 made of metal such as stainless steel and a lower casing 12 made of insulating material such as plastic.

The upper casing 10 has a hexagonal bolt shape, and the outer peripheral surface of the head portion 10a is formed into a hexahedron.
A screw 10c is cut on the outer peripheral surface of the rod portion 10b. A hole 14 is formed in the center of the upper casing 10 in the axial direction.

The hole 14 has an inlet portion 14a that is tapered outward at the tip of the rod portion 10b, and a fluid inlet portion 14b that extends from the inlet portion 14a toward the inner depth with a uniform diameter. , A piston guide portion 14c having a diameter larger than that of the fluid drawing portion 14b and for guiding the cylindrical piston 16 in the axial direction, and a piston rod 16a extending in the axial direction from the lower end of the piston 16. And a small diameter piston rod guide portion 14d.

The piston guide portion 14c is, for example, an inner peripheral surface of a ring-shaped seal member 18 made of, for example, an O ring for blocking the upper end side and the lower end side of the piston 16, and for holding the seal member 18, for example. It is formed by the inner peripheral surface of the ring-shaped seal support member 20 made of Teflon and the upper inner peripheral surface of the piston guide member 22 which also provides the piston rod guide portion 14d. A flange portion 22a is provided on the upper outer peripheral surface of the piston guide member 22, and a ring-shaped projecting piece portion 10d formed on the upper casing 10 is provided.
Is crimped to the flange portion 22a from below. By caulking from below, the seal member 18, the seal support member 20, and the piston guide member 22 are integrally assembled as a subassembly to form a piston guide unit.

Facing the tip of the piston rod 16a,
On the upper part of the lower casing 12, a snap action disk 24 made of a conductive spring material such as stainless steel is provided.
Is provided. The snap action disc 24 has a dish-shaped disc seat member 26 at the outer peripheral edge thereof.
Supported by the disk, the disk central portion is properly displaced between a first position (a position shown in FIG. 1) where the disk central portion is curved upward and a second position (a position shown in FIG. 2) where the disk central portion is curved downward. It is like this.

A contact guide member 28 made of an insulating material, such as plastic, is attached to an opening 26a formed in the center of the disk seat member 26 which is recessed in a stepwise manner, and is provided in the contact guide member 28 in the axial direction. Through hole 2
A cylindrical contact 30 is slidably arranged on 8a. A groove 30 is formed on the outer peripheral surface of the lower end of the contact 30.
a is formed, and the opening 32a at the center of the leaf spring 32 is engaged with the groove 30a. The leaf spring 32 is made of, for example, a conductive spring material such as beryllium copper.
4 and the fixed conductor piece 36, the contact 30
It carries elastically.

The fixed insulating piece 34 is fixed on a conductor piece 40 extending in a U-shape from the base end of one terminal 38 to the back surface of the disk seat member 26. The fixed conductor piece 36 is fixed to the base end of the other terminal 42. Both terminals 38 and 42 are planted in the base portion 12a of the lower casing 12 and project into the skirt portion 12a of the lower casing 12. The skirt portion 12a of the lower casing 12 and both terminals 3
The socket portion of the present pressure switch is formed by the protrusions of 8, 42.

Thus, in the lower casing 12,
Snap action disc 24 and contact 30
Both of which are opposed to each other as a movable contact and a fixed contact, the snap action disk 24 is always connected to one terminal 38 through the disk seat member 26 and the conductor piece 40, and the contact 30 is the leaf spring 32 and the conductor piece. It is always connected to the other terminal 42 via 36. Then, when the snap action disk 24 is in the first position, as shown in FIG.
When the snap action disk 24 is in the second position, the contacts 24 and 30 come into pressure contact with each other to be in the switch closed state. Is configured. Whether the snap action disk 24 is in the first position or the second position, that is, the switch open state or the switch closed state, is determined by the snap action disk 2
4 depends on whether the pressing force of the piston 16 acting from above is smaller or larger than a predetermined value, and in turn, depends on whether the pressure of the fluid acting on the upper end surface of the piston 16 is lower or higher than a set value.

Next, the operation of this pressure switch will be described. This pressure switch is attached such that the rod portion 10b of the upper casing 10 is screwed into a screw hole of a pipe or the like in a pneumatic system or a hydraulic system. When mounting, the hexagonal head 10a of the upper casing 10
All you have to do is hang a screw on the wrench. Both terminals 38, 4
2 is connected to both electrode terminals of the switch circuit.

The working fluid in the pneumatic or hydraulic system to which the present pressure switch is attached is the inlet portion 14 of the hole 14.
It is drawn into the fluid drawing portion 14b from a and acts on the upper end surface of the piston 16. As a result, a pressing force defined by the product of the fluid pressure and the area of the upper end surface of the piston 16 is applied to the upper end surface of the piston 16. This pressing force snaps from the piston rod 16a via the piston 16.
It is provided at the center of the action disc 24.

The snap action disk 24 is
It is a spring member corresponding to a flat spring with the diameter of the central opening zero, and resists the pressing force as long as the pressing force from the piston 16 does not exceed a predetermined value, that is, the fluid pressure does not exceed a set value. And remains in the first position as shown in FIG. Thus, when the snap action disk 24 remains in the first position, the snap action disk 24 and the contact 30 are separated from each other, so that the terminals 38 and 42 are electrically disconnected from each other and the switch. Keep open.

As the fluid pressure rises, the pressing force exerted by the piston 16 on the snap action disk 24 increases in proportion to the fluid pressure. Then, when the fluid pressure reaches the set value, snapping from the piston 16
The pressing force applied to the action disk 24 reaches a predetermined value, that is, the snap action point, and the snap action
The disk 24 is properly inverted and displaced from the first position to the second position, and abuts on the upper end surface of the contact 30 as shown in FIG. The pressing force from the snap action disk 24 to the contact 30 is elastically received by the leaf spring 32. As a result, the snap action disk 24 and the contact 30 are brought into pressure contact with each other at an appropriate pressure. As described above, when the fluid pressure exceeds a predetermined value, the snap action disk 24 is displaced from the first position to the second position by the pressing force from the piston 16 and press-contacts with the contact 30. By both terminals 3
The electric circuit between 8 and 42 becomes conductive, and a switch-on signal is obtained.

Snap action disk 2
When 4 is displaced to the second position, the piston 16 moves downward, but the step portion 22b of the piston guide member 22 acts as a stopper to restrict the downward movement of the piston 16. Therefore, even if the fluid pressure becomes excessive,
There is no risk of excessive load being applied to the snap action disk 24 and other parts.

Thereafter, when the fluid pressure decreases, the pressing force applied from the piston 16 to the snap action disk 24 decreases in proportion to the fluid pressure. And
When the snap action point of the snap action disk 24 decreases to the snap action point, the restoring force of the leaf spring 32 causes snap action.
The action disc 24 is flipped from the second position to the first position to separate from the contact 30. As a result, the pressure switch returns to the switch open state.

As described above, in the pressure switch of this embodiment, the piston 16 is used as the means for converting the fluid pressure into the switch driving force, instead of the diaphragm.
Fluid pressure is applied to the upper end surface of the piston 16. By reducing the diameters of the fluid drawing portion 14b and the piston 16, a large fluid pressure can be converted into a small switch driving force. Therefore, each part or part in the switch and the casing can be downsized and thinned. In addition, the seal member 1 which constitutes the piston guide means
8. Since the seal support member 20 and the piston guide member 22 are integrally assembled as a sub-assembly by caulking, the manufacturing and productivity of the switch can be improved. Further, since the snap action disk 24 is also used as the movable contact, the number of parts can be reduced and the design can be simplified. A movable contact may be provided separately from the snap action disk 24, and the movable contact may be driven by the displacement of the snap action disk 24.

FIGS. 3 and 4 are sectional views showing the structure of the pressure switch according to the second embodiment. FIG. 3 shows the switch open state and FIG. 4 shows the switch closed state.
In these figures, parts having the same configurations and functions as those in FIGS. 1 and 2 are designated by the same reference numerals. The same applies to subsequent figures.

As shown in FIGS. 3 and 4, in the second embodiment, in the pressure switch of the first embodiment described above, a converter 44 is provided between the piston rod 16a and the snap action disk 24. It is inserted. This converter 44 is a rigid disc made of stainless steel, for example, and has an annular projection 44a on the outer peripheral edge of the lower surface. For the piston rod 16a, the lower end surface of the rod is received at the central portion of the upper surface and snaps. ·action·
On the disk 24, an annular projection 44a is placed as a contact at the disk intermediate portion.

The snap action disk 24 is
The spring member is a spring member that is inverted and displaced between a first position in which the center part of the disk warps upward and a second position in which the center part of the disk warps downward with the contact point between the disk seat member 26 and the outer peripheral edge of the disk as a fulcrum.
Therefore, when the pressing force from the piston 16 is applied to the middle portion of the snap action disc 24 via the converter 44 as in the present embodiment, the pressing force is directly applied from the piston rod 16 to the center portion of the disc. Since the distance between the fulcrum and the point of action is shorter than that in the case where the force is applied, the moment acting on the snap action disk 24 becomes smaller, and the fluid pressure required to perform the snap operation from the first position to the second position. Becomes higher. That is, by providing the converter 44, the fluid pressure can be converted into a smaller switch driving force. Therefore, the pressure switch can be operated with a higher fluid pressure.

FIGS. 5 and 6 are sectional views showing the structure of the pressure switch according to the third embodiment. FIG. 5 shows the switch closed state and FIG. 6 shows the switch opened state.

The pressure switch of the first and second embodiments described above has a snap switch as shown in the schematic view of FIG.
When the action disc 24 is in the first position (when the fluid pressure is lower than the set value), the switch is open, and when the snap action disc 24 is displaced to the second position (the fluid pressure is set). Single-pole single-throw (SPST: Single) when the switch is closed when the value is exceeded.
Pole Single Throw type normally open (NO: Nomally O)
pened) switch configured. On the other hand, in the pressure switch of the third embodiment, the switch logic is reversed, and the single pole single throw (SPST) type normally closed (NC :) is schematically shown in FIG. 7B. Nomally Closed) switch.

5 and 6, a converter 46 is inserted between the piston rod 16a and the snap action disc 24, and an annular protrusion 26b is formed at the edge of the stepped recess of the disc seat member 26. The snap action disk 24 is supported by the protrusion 26b. In the converter 46, the surface (upper surface) facing the piston rod 16a is formed into a flat surface, the surface (lower surface) facing the snap action disk 24 is formed into a curved concave surface, and the outer peripheral edge portion of the lower surface is formed. A step portion 46 a for engaging with the outer peripheral edge portion of the snap action disk 24 is provided. The pressing force from the piston 16 passes through the converter 16,
It is provided on the outer peripheral edge of the snap action disk 24.

When the fluid pressure is lower than the set value, FIG.
As shown in FIG. 5, the snap action disk 24 is in a downwardly curved first position, and the lower surface of the center of the disk is in pressure contact with the upper end surface of the contact 30.
As a result, the electric circuit between the terminals 38 and 42 is conducted, and the switch is closed. Snap action from converter 46 in proportion to increasing fluid pressure.
The pressing force applied to the disc 24 increases. And
When the pressing force reaches the snap operation point, the snap action disk 24 is inverted and displaced to the second upwardly curved position as shown in FIG. 6 with the annular projection 26b of the disk seat member 26 as a fulcrum. Then, the snap action disk 24 is separated from the contact 30, the contact between the contacts 24 and 30 is cut off, and the switch is opened. When the fluid pressure decreases to the snap action point, the snap action disc 24 is reversely displaced from the second position to the first position by its own restoring force with the annular projection 26b of the disc seat member 26 as a fulcrum. To do.

In the third embodiment, the pressing force from the piston 16 is applied to the outer peripheral edge portion (point of action) of the snap action disk 24 via the converter 46, and the annular projection 26b of the disk seat member 26 is used as a fulcrum. As disk 2
Since it is arranged to reversely displace 4 between the first position and the second position, as in the first embodiment, the piston rod 1
Since the distance between the fulcrum and the point of action is shorter and the moment acting on the snap action disk 24 is smaller than in the method of directly applying a pressing force from 6 to the disk center,
The fluid pressure can be converted into a smaller switch driving force, and the switch operation can be performed at a higher fluid pressure. In the third embodiment, the spring force for urging the snap action disc 24 from the first position curved upward to the second position curved downward is
It derives from the resilience of the snap action disc 24.

FIG. 8 is a sectional view showing the structure of the pressure switch according to the fourth embodiment. In this fourth embodiment, the piston rod 16a and the snap action disc 2 are used.
A diaphragm 48 is provided between the diaphragm 48 and the diaphragm 4. The diaphragm 48 may be an ordinary flexible one, and the peripheral portion thereof is sandwiched and held between the upper casing 10 and the lower casing 12, and the central portion thereof bends following the downward movement of the piston rod 16a. Has become. With this diaphragm 48, the piston 16 side and the snap action disk 24 side are connected with respect to the switch driving force, but are disconnected with respect to the fluid. Thereby, on the piston 16 side, for example, fluid from the seal 18,
Even if the liquid leaks, the leaked fluid is
8 disconnects the electric circuit portion in the lower casing 12 from reaching the contact portions 24, 30 and the like. Therefore, malfunction or failure can be prevented.

FIG. 9, FIG. 10 and FIG. 11 are sectional views showing the structure of the pressure switch according to the fifth embodiment.
11 is a diagram showing a state where the fluid pressure is a steady value (switch closed state), FIG. 10 is a diagram showing a state when the fluid pressure has reached a set value lower than the steady value (switch opened state), FIG.
FIG. 6 is a diagram showing a state (switch open state) when the fluid pressure has reached a set value higher than a steady value.

The pressure switch of this embodiment is used when the pressure is above the lower limit setting and below the upper limit setting, that is, at an intermediate value, and when the fluid pressure is below the lower limit setting or above the upper limit setting. It is a binary pressure switch with different (binary) switch states.

9 to 11, the pressure switch according to the present embodiment is structurally constructed so that the parts (particularly the piston mechanism) in the upper casing 10, the snap action disk 24 and the converter 46 are the same as those of the third embodiment. It is common with the embodiment, but the rest is different.
Between the upper casing 12 and the lower casing 50,
A bottomed cylindrical inner casing 52 is provided, and the snap action disc 24 and the converter 46 are housed in the inner casing 52. An opening 52a is formed at the center of the bottom surface of the inner casing 52, and a cylindrical movable contact operating rod 54 is fitted in the opening 52a with play so as to be movable in the axial direction. The upper end surface of the movable contact operating rod 54 is brought into pressure contact with the center of the lower surface of the snap action disk 24, and the lower end surface thereof is applied to the intermediate portion of the conductive leaf spring 58 having the movable contact portion 56 attached to the tip thereof. It is in pressure contact.

In the inner casing 52, the snap action disk 24 is provided with the movable contact operating rod 5.
4 is arranged on a movable disk seat member 60 fitted with play at the upper end of the disk 4. An annular protrusion 60a is provided on the upper surface of the intermediate portion near the outer peripheral edge of the disc seat member 60, and the snap action disc 24 is curved downward at a first position and upwardly curved with the protrusion 60a as a fulcrum. It is adapted to be inverted and displaced with respect to the second position. On the lower surface of the inner peripheral edge of the disk seat member 60, a tubular portion 60b for guiding the movable contact operating rod 54 extends in the axial direction, and a projection 60c is provided on the outer side of the tubular portion 60b. . The outer peripheral portion of the bottom surface of the inner casing 52 is raised in a stepwise manner, and the outer peripheral edge portion of the flat spring 62 is placed on the flat portion 52b.
The lower surface protrusion 60c of the disk seat member 60 is in contact with the upper surface of the inner peripheral edge of the disk seat member 60. Therefore, the counter spring 62 includes the converter 46, the snap action disc 24, the movable contact operating rod 54, and the disc seat member 6.
The load from the piston 16 according to the fluid pressure is applied via 0. When the fluid pressure is lower than the lower limit set value, the countersunk spring 62 is displaced to the first position (see FIGS. 9 and 11) which assumes a substantially flat shape or a conical shape with some central depression. When the fluid pressure becomes equal to or higher than the lower limit set value, the countersunk spring 62 is adapted to be inverted and displaced to the second position (see FIG. 10) which has a conical shape in which the center portion is lifted upward.

In the lower casing 50, the base end of the conductive leaf spring 58 is curved in a U shape and fixed to one terminal 64. Further, a conductor piece 66, which faces the movable contact portion 56 and constitutes a fixed contact portion, is provided below the movable contact portion 56. The conductor piece 66 is fixed to the other terminal 68.

In such a switch configuration, snap
A pressing force from the piston 16 corresponding to the fluid pressure is applied to the outer periphery of the action disk 24 from the upper side, and from the lower side, the spring force of the leaf spring 58 and the counter spring 52 are applied.
Is applied to the center of the disc. As long as the fluid pressure is below the upper set point, the snap action disc 24 remains in the downwardly curved first position. Also, as long as the fluid pressure is higher than the lower limit setting value,
2 is pressed to a substantially flat first position. Therefore, when the fluid pressure is within the pressure range higher than the lower limit set value and lower than the upper limit set value, that is, at the intermediate value, the piston 16 descends to the intermediate position and snaps as shown in FIG. The action disk 24 and the counter spring 62 are respectively in the first position, the movable contact operating rod 54 is lowered to the lower limit position, the leaf spring 58 is bent downward, and the movable contact portion 56 at the tip thereof is fixed contact portion 66. Pressure contact. In this state, both terminals 64, 68
The spaces are electrically connected through the leaf spring 58, the movable contact portion 56, and the fixed contact portion 66, and the switch is closed.

However, as the fluid pressure decreases, the position of the piston 16 gradually rises, and when the fluid pressure decreases to the lower limit set value, the restoring force of the flat spring 62 overcomes the pressing force from the piston 16 and the flat spring 62 moves to the first position. The disc seat member 60, the snap action disc 24 and the converter 46 are properly displaced from the first position to the second position.
Lift up. As a result, as shown in FIG. 10, the movable contact operating rod 54 is raised by the restoring force of the leaf spring 58, and the movable contact portion 56 is separated from the fixed contact portion 66. As a result, the terminals 64 and 68 are disconnected from each other and the switch is opened.

Further, when the fluid pressure rises from the switch closed state (FIG. 9) and the position of the piston 16 gradually falls and the fluid pressure reaches the upper limit set value, the snap action disc 24 causes the disc seat member 60 to move. Upper surface protrusion 60
It is properly inverted to the second position with a as a fulcrum, and the central part of the disk is displaced upward. Then, as shown in FIG. 11, the movable contact operating rod 54 rises due to the restoring force of the leaf spring 58, and the movable contact portion 56 separates from the fixed contact portion 66. As a result, the terminals 64 and 68 are disconnected from each other and the switch is opened.

Also in the binary pressure switch of this embodiment, since the fluid pressure is converted into the switch driving force by the piston mechanism similar to that of the first to fourth embodiments,
It is possible to obtain a small and thin switch. In this embodiment, the switch is closed when the lower limit value is set and the upper limit value is set or less, that is, the intermediate value, and the switch is opened when the fluid pressure is set to the lower limit value or more or the upper limit value or more. Although it is configured to take the state, it is natural that it can be modified to a switch configuration that takes the opposite logic.

In each of the above-mentioned embodiments, the switch state is reversed when the fluid pressure reaches the set value. However, the set value is the diameter of the piston 16 and the spring of the snap action disk 24. Force, leaf spring 32,
It is possible to change it to an arbitrary value by selecting an appropriate value such as the spring force of 58. Furthermore, leaf springs 32, 5
It is also possible to change the fluid pressure set value at any time by providing adjusting means capable of variably adjusting the elastic repulsive force from the 8 side to the piston side.

[0050]

As described above, according to the pressure switch of the present invention, the piston mechanism converts the fluid pressure into the switch driving force to displace the snap action disk, and the switch is switched by the disk displacement. Since this is performed, a highly reliable pressure switch can be obtained with a compact and simple structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a pressure switch according to a first embodiment of the present invention, showing a switch open state.

FIG. 2 is a cross-sectional view showing the configuration of the pressure switch according to the first embodiment of the present invention, showing the switch closed state.

FIG. 3 is a cross-sectional view showing the configuration of a pressure switch according to a second embodiment of the present invention, showing the switch open state.

FIG. 4 is a sectional view showing the configuration of a pressure switch according to a second embodiment of the present invention, showing the switch closed state.

FIG. 5 is a cross-sectional view showing the configuration of a pressure switch according to a third embodiment of the present invention, showing the switch closed state.

FIG. 6 is a cross-sectional view showing the configuration of a pressure switch according to a third embodiment of the present invention, and is a view showing a switch open state.

FIG. 7 is a diagram conceptually showing a single-pole / single-throw normally open switch and a single-pole / single-throw normally closed switch configured as a pressure switch of the embodiment.

FIG. 8 is a sectional view showing the structure of a pressure switch according to a fourth embodiment of the present invention.

FIG. 9 is a cross-sectional view showing the structure of a pressure switch according to a fifth embodiment of the present invention, showing a state where the fluid pressure is at a steady value (switch closed state).

FIG. 10 is a sectional view showing the structure of a pressure switch according to a fifth embodiment of the present invention, showing a state (switch open state) when the fluid pressure has reached a set value lower than a steady value. is there.

FIG. 11 is a cross-sectional view showing the structure of the pressure switch according to the fifth embodiment of the present invention, showing a state (switch open state) when the fluid pressure has reached a set value higher than a steady value. is there.

[Explanation of symbols]

 10 Upper casing 12 Lower casing 14b Fluid intake part 14c Piston guide part 14d Piston rod guide part 16 Piston 16a Piston rod 18 Ring-shaped seal 20 Seal support member 22 Piston guide member 24 Snap action disk 30 Contact 32 Leaf spring 36, 40 Conductor piece 38,42 Terminal 44,46 Converter 48 Diaphragm

Claims (4)

[Claims] 1. A piston member arranged in a space formed in communication with a fluid passage and movable according to a fluid pressure; a piston guide member arranged in the space for guiding the piston member; A second position from the first position in response to the movement of the piston member;
Of the first conductive member and the second conductive member, and the first conductive member and the second conductive member are electrically connected to each other in response to the displacement of the displacement member. A switch member for connecting or disconnecting the pressure switch. 2. A converter member for adjusting a pressurizing moment applied from the piston member to the displacement member is provided between the piston member and the displacement member. pressure switch. 3. The diaphragm according to claim 1, wherein a diaphragm is provided between the piston member and the displacement member to shut off the fluid between the piston member side and the displacement member side. pressure switch. 4. A piston member which receives a fluid pressure on one end surface, a piston guide means for guiding the piston member, and a pressing force from the piston member which is arranged so as to face the other end surface of the piston member. Is a first predetermined value or more, the snap action disc is displaced from the first disc position to the second disc position, and the snap action disc is moved from the second disc position to the first disc position. Spring means for urging to the side,
A pressure switch, comprising: a counter spring that is displaced from a first spring position to a second spring position when the pressing force from the piston member becomes equal to or less than a second predetermined value.