JP2010020922A - Pressure switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure switch capable of eliminating an influence of slide resistance. <P>SOLUTION: This pressure switch is provided with a switch 4, a lever 6, a plunger 18, and a coil spring 36, in a casing 2. The lever 6 contacts with the switch 4, in its acting part 6a, and is supported turnably by a fulcrum part 6b. The acting part 6a operates the switch 4 by prescribed-directional turn of the lever 6 around the fulcrum part 6b. The coil spring 36 imparts a force for turning the lever 6 along a direction reverse to a prescribed direction, to the lever 6 via a coil spring 30. The plunger 18 contacts with a power point part 6c of the lever 6, in its one end, and slides to turn the lever 6 along the prescribed direction, when a force by pressure of a fluid supplied to the other end varies greatly exceeding a force of the coil spring 36. The coil spring 36 is provided noncontactly with an inner face of the casing 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressure switch that detects a change in fluid pressure.

  Conventional pressure switches include those disclosed in Non-Patent Document 1, for example. According to the technique of Non-Patent Document 1, a spring chamber is formed inside the main body, a piston hole is provided in the bottom wall of the spring chamber, and a piston is inserted into the piston hole. A passage is formed in the lower part of the spring chamber, and fluid is supplied from the pressure source. As a result, the tip of the piston enters the spring chamber. A first spring receiver is formed around the tip of the piston, and a second spring receiver is provided at the upper end of the spring chamber. A coil spring is disposed between the first and second spring receivers. A cylindrical portion is disposed on the second spring receiver. Flange is formed at both ends of this cylindrical portion, and these flanges are in contact with the wall of the spring chamber. Further, the flange of the cylindrical body on the first spring receiving portion side is in contact with a switch provided in the main body via a cam. When the pressure of the fluid supplied to the passage is larger than the elastic force of the coil spring, the piston rises, pushes up the first spring receiver, the cam rotates in a predetermined direction, and the switch is operated.

http: // www. sr-engineering. co. JP / seihin / 2-3. accessory / SR-ACCESSORY5. pdf

  In the pressure switch configured as described above, since the cylindrical body is in contact with the wall of the spring chamber, a sliding resistance is generated, and there is a deviation of the sliding resistance between the force acting on the plunger and the spring force. appear. Since the direction of sliding resistance is reversed between the movement when the plunger is raised and the movement when the plunger is lowered, a large deviation occurs in the force acting on the plunger, and the pressure when the pressure switch is turned on and off The pressure when becoming may be different.

  An object of this invention is to provide the pressure switch from which the influence of sliding resistance was removed.

  The pressure switch of one embodiment of the present invention includes a switch, a driving unit, a plunger, and an elastic unit in a housing. The drive means has a fulcrum part, an action part, and a force point part. The action part is in contact with the switch and is rotatably supported by the fulcrum part. For example, a lever or a cam can be used as the drive means for the action portion to operate the switch by rotating the drive means around a fulcrum in a predetermined direction. The operation of the switch may be to turn on or off the contact of the switch. The elastic means gives the driving means a force for rotating the driving means in a direction opposite to the predetermined direction. The plunger slides when the force due to the pressure of the fluid supplied to the other end changes more than the force of the elastic means and rotates the drive means in the predetermined direction. Let The elastic means is provided in non-contact with the inner surface of the housing.

  In the pressure switch configured as described above, when the fluid pressure increases, the plunger slides while compressing the elastic means against the elastic force of the elastic means, the driving means rotates in a predetermined direction, and the switch is operated. The Further, when the fluid pressure decreases, the driving means and the plunger are returned to their original positions by the elastic force of the elastic means. In this operation, the elastic means is compressed or returned to its original state. At this time, since the elastic means is not in contact with the wall surface of the casing, there is no sliding resistance, and the operation by the sliding resistance is performed. There is no error.

  It is desirable that the plunger makes point contact with the force point portion. For example, at least a hemispherical portion can be provided in the power point portion, and the plunger can be brought into contact therewith. By making point contact in this way, the contact resistance between the plunger and the force point portion is reduced.

  A first elastic means receiving portion fixed in the housing is provided at one end of the elastic means, a second elastic means receiving portion is provided at the other end of the elastic means, and a protrusion from the second elastic means receiving portion. Can be protruded toward the drive means. In this case, the power point portion of the driving means has a through hole into which the protrusion enters. A contact portion is provided so as to come into contact with the protrusion within the through hole. The plunger is in contact with the contact portion on the side opposite to the protrusion, and can slide the contact portion in the direction of the protrusion. The contact portion moves the protrusion toward the first elastic body receiving portion while compressing the elastic means in a state where the contact portion is in contact with the through hole by sliding the plunger in the direction of the protrusion. When the compressive force of the elastic means becomes larger than the force of the plunger, the contact portion is brought into a non-contact state with the through-hole according to the movement of the protrusion toward the plunger, and the second elastic means receiving portion The compressive force of the elastic means is applied to the force point portion via another elastic means provided between the force point portions.

  If comprised in this way, the contact part will move to the 2nd elastic means receiving part side in the state which contacted the power point of the drive means by the slide of the plunger by the raise of fluid pressure, and a drive means will rotate in a predetermined direction. At this time, the second elastic means receiving portion moves toward the first elastic means receiving portion and compresses the elastic means. In this state, the other elastic means is hardly compressed. When the compressive force of the elastic means becomes larger than the force of the plunger due to a decrease in fluid pressure, the second elastic means receiving portion moves to the plunger side. At this time, the contact portion is not in contact with the through hole, and another elastic means applies a compressive force to the force point portion of the drive means, so that the drive means rotates in a direction opposite to the predetermined direction.

  As described above, according to the pressure switch of the present invention, the influence of sliding resistance can be eliminated.

  The pressure switch according to the first embodiment of the present invention has a housing 2 as shown in FIG. A switch 4 is disposed in the housing 2. This switch 4 has an operation part 4a, and when the operation part 4a is pushed, a contact provided inside is closed. It is also possible to use a type of switch in which the internal contact is opened when the operation unit 4a is pressed.

  Driving means, for example, the action portion 6a of the lever 6 is in contact with the operation portion 4a. The lever 6 is generally T-shaped, and one leg portion 8 thereof is disposed along the length direction of the switch 4, and the vicinity of one end thereof serves as an action portion 6 a, which contacts the operation portion 4 a. ing. The position on the other end side rather than the center of the leg portion 8 is a fulcrum portion, and it is around a shaft 6b provided in the thickness direction of the leg portion 8 (the front and back direction of the paper surface of FIG. 1). It is supposed to be rotatable. The vicinity of the tip of the leg 10 extending almost perpendicularly to the leg 8 from the vicinity of the center of the leg 8 is a force point 6c.

  As shown in an enlarged view in FIG. 2, the force point portion 6 c has a through hole 6 d formed in a direction parallel to the length direction of the leg portion 8. A contact portion, for example, a steel ball 12 is disposed on the opposite side of the through hole 6d from the action portion 6a. In this arrangement state, a part of the steel ball 12 protrudes from the leg part 10 in the direction opposite to the action part 6a. The steel ball 12 is movable in the length direction of the leg portion 8 and can take either a state in contact with the wall of the through hole 6d or a non-contact state.

  When the steel ball 12 moves in the direction opposite to the action portion 6a, the steel ball 12 comes into contact with a seat 14 provided in the housing 2. A pressure chamber 16 is formed in a direction opposite to the action portion 6 a along the length direction of the leg portion 8 of the lever 6, continuing to the seat 14. A cylindrical plunger 18 is disposed in the pressure chamber 16, and one end thereof is in point contact with the steel ball 12. The plunger 18 is slidable along the length direction thereof, that is, the length direction of the leg portion 8. A pressure fluid, for example, pressure oil, is supplied into the pressure chamber 16 from a port 20 provided in the side of the casing 2 on the side, and when the pressure rises, the pressure is applied to the other end of the plunger 18. The plunger 18 slides toward the steel ball 12 side. Note that air or water to which pressure is applied may be used instead of the pressure oil.

  A protrusion 22 is provided on the opposite side of the steel ball 12 from the plunger 18. The protrusion 22 has a curved surface complementary to the spherical surface of the steel ball 12 at one end, and is in contact with the steel ball 12 in the through hole 6d. The other end of the protrusion 22 is fixed to the center of the second elastic body receiving portion, for example, the spring receiver 24. The spring receiver 24 is disposed at a distance from the leg 10 of the lever 6, and a spring seat 26 is formed around the protrusion 22 on the side of the steel ball 12 of the spring receiver 24, and is opposed thereto. Thus, a spring seat 28 is also formed around the protrusion 22 in the force point portion 6c of the lever 6, and another elastic means such as a coil is provided between the spring seats 26, 28 so as to surround the periphery of the protrusion 22. A shaped return spring 30 is arranged.

  On the opposite side of the steel ball 12 so as to face the spring receiver 24, a first elastic body receiver, for example, a spring receiver 32, is arranged at a distance from the spring receiver 24. The spring receiver 32 is attached to the inside of the housing 2 by a screw 34 inserted from the outside into the housing 2, and the distance to the spring receiver 24 is changed by adjusting the position of the screw 34. An elastic means, for example, a coil spring 36 is disposed between the spring receivers 24 and 32. Therefore, the compression degree of the coil spring 36 can be adjusted by the screw 34. The coil spring 36 and the spring receiver 24 are not in contact with the inner surface of the housing 2 in the housing 2. Note that the elastic force of the coil spring 36 is much larger than the elastic force of the coil spring 30.

  In the pressure switch configured as described above, in the state shown in FIG. 1, the pressure of the fluid supplied to the pressure chamber 16 increases, and the force pushing the plunger 18 by the pressure is greater than the force set by the coil spring 36. When the plunger 18 starts to slide, the steel ball 12 comes into contact with the through hole 6d of the lever 6, and the lever 6 is switched to the switch 4 while the coil spring 36 is compressed by the protrusion 22 according to the sliding of the plunger 18. Rotate to the side. As a result, as shown in FIG. 3, the operating portion 4a of the switch 4 is pushed in by the action portion 6a of the lever 6, and the switch 4 operates. By appropriately setting the distance between the action part 6a and the shaft 6b of the fulcrum part and the distance between the shaft 6b of the fulcrum part and the force point part 6c, the sensitivity of operating the operation part 4a can be increased.

  When the pressure of the fluid supplied to the pressure chamber 16 decreases and the force set by the coil spring 36 becomes larger than the force pushing the plunger 18, the spring receiver 24 moves to the pressure chamber 16 side, and the protrusion 22 is made of steel. The ball 12 is pushed, and the steel ball 12 moves away from the through hole 6 d of the lever 6. Thereafter, the force point 6c of the lever 6 is pushed toward the pressure chamber 16 by the return spring 30 and returns to the original position. As a result, the state in which the operation portion 4a of the switch 4 is pushed by the action portion 6a is released, and the switch 4 also returns to the original state.

  While the operation of the switch 4 is performed, neither the coil spring 36 nor the spring receiver 24 is in contact with the inner surface of the housing 2. Therefore, the operation of the switch 4 is not affected by the sliding resistance. Moreover, since the plunger 18 is in point contact with the steel ball 12, the contact resistance is small. In addition, when the lever 18 is rotated so that the plunger 18 or the protrusion does not directly drive the lever 6 and the switch 4 is operated, the steel ball 12 moves on the circumference of the circumferential surface of the force point portion 6c. It is only in contact with the inner surface, and the contact resistance is very small.

  Further, when the lever 6 is returned to the original position, the lever 6 is returned to the original position by the return spring 30 that is in contact with the lever 6 on one circumference around the protrusion 22, and at this time, the steel ball 12 is moved to the lever 6. Therefore, there is little contact resistance at the fulcrum shaft 6b. For example, when the plunger 18 is in direct contact with the lower end of the force application portion 6c of the lever 6 and the protrusion 22 is in contact with the upper end of the force application portion 6c without providing the through hole 6d and the steel ball 12, the protrusion 22 However, when the through hole 6d, the steel ball 12, the protrusion 22, and the return spring 30 are provided as described above, the contact resistance of the fulcrum shaft 6b is reduced. Can be reduced.

  A pressure switch according to a second embodiment of the present invention is shown in FIG. This pressure switch is configured in the same manner as the pressure switch of the first embodiment except that the port 20a is formed not on the side of the pressure chamber 16 but on the opposite side of the steel ball 12 and connected to the pressure chamber 16. Yes. The same parts are denoted by the same reference numerals, and the description thereof is omitted.

  In both the above-described embodiments, the steel ball 12 is used. However, as long as the synthetic spherical body is used, other materials can be used, and the tip of the plunger 18 is formed in a hemispherical shape. Instead, a cylindrical portion can be used. However, in this case, an engagement portion in which the cylindrical body engages with the power point portion of the lever 6 by sliding the plunger 18 is provided in the cylindrical portion. Moreover, in both said embodiment, although the protrusion 22 and the steel ball 12 were formed separately, it can also form integrally. In the above embodiment, the lever 6 is used, but a cam can be used instead. In the above embodiment, a part of the steel ball 12 is protruded from the leg portion 10 in the direction opposite to the action portion 6a, but it is not necessarily required to protrude. Further, as the switch 4, a non-contact type switch can also be used.

It is a longitudinal cross-sectional view before the action | operation of the pressure switch of the 1st Embodiment of this invention. FIG. 2 is a partially enlarged view of FIG. 1. It is a longitudinal cross-sectional view after the action | operation of the pressure switch of FIG. It is a longitudinal cross-sectional view of the pressure switch of the 2nd Embodiment of this invention.

Explanation of symbols

2 Housing 4 Switch 6 Lever 6a Action part 6b Support point part 6c Force point part 18 Plunger 36 Coil spring (elastic means)

Claims (3)

A switch,
It has a fulcrum part, an action part, and a force point part, the action part is in contact with the switch, is rotatably supported by the fulcrum part, and the action part operates the switch by rotating in a predetermined direction around the fulcrum part. Switch driving means for
Elastic means for applying a force to the lever to rotate the switch driving means in a direction opposite to the predetermined direction;
A plunger that contacts one end of the force point portion and slides to rotate the switch driving means in the predetermined direction when the force due to the pressure of the fluid supplied to the other end changes more than the force of the elastic means; ,
A pressure switch provided in a housing, wherein a peripheral surface of the elastic means is not in contact with an inner surface of the housing.   The pressure switch according to claim 1, wherein the plunger is in point contact with the force point portion. The pressure switch according to claim 1.
A first elastic means receiving portion fixed in the casing is provided at one end of the elastic means, a second elastic means receiving portion is provided at the other end of the elastic means, and from the second elastic means receiving portion, The protrusion protrudes toward the driving means,
The force point portion of the driving means has a through-hole into which the protrusion enters, and a contact portion is provided so as to contact the protrusion within the through-hole, and the plunger is connected to the protrusion on the contact portion. The contact portion is slidable in the direction of the protrusion, and the contact portion is configured to slide the protrusion in a state of contacting the through-hole by sliding the plunger in the direction of the protrusion. 1 is moved while compressing the elastic means to the elastic body receiving part side of 1,
When the compressive force of the elastic means becomes larger than the force of the plunger, the contact portion is brought into a non-contact state with the through-hole according to the movement of the protrusion toward the plunger side, and the second elastic means receiving portion and A pressure switch in which a compressive force of the elastic means is applied to the force point portion via another elastic means provided between the force point portions.

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