Pressure switch

Abstract

The present invention provides a pressure switch that can prevent the detachment of a working plate and improve the pressure resistance even when an excessive pressure is applied to a pressure follower portion, thereby suppressing the breakage of the pressure follower portion and preventing the leakage of a pressure medium. The pressure switch (1) includes: a limit shaft (7) provided in a direction parallel to the axial direction of a fulcrum (2a) near a working plate (4) inside a main body (2); and an anti-offset stopper (9) provided at a position on the working plate (4) closer to the end side of a lateral side portion (4b) than the limit shaft (7), and restricts the movement of the working plate (4) by the anti-offset stopper (9) abutting against the limit shaft (7) even when an excessive pressure is applied to the bellows (3).

Description

Technical Field

[0001] The present invention relates to a pressure switch. Background Art

[0002] Conventionally, as a pressure switch, a structure is known which includes, inside a main body: a bellows serving as a pressure follower; an L-shaped working plate that rotates about a fulcrum provided on the main body as the bellows expands and contracts; a spring connected to a longitudinal side portion of the working plate to oppose the movement of the working plate; a working shaft that follows the movement of the working plate; and a movable contact plate that controls a microswitch by the movement of the working shaft (for example, refer to Patent Documents 1 and 2).

[0003] In this pressure switch, one end side of the working shaft is engaged with the longitudinal side portion of the working plate, and the other end side is engaged with the movable contact plate that constitutes the microswitch. In addition, the microswitch includes, for example, two fixed contacts and a movable contact disposed between them. In the microswitch, the movable contact relative to the fixed contacts is provided at the free end portion of the movable contact plate. The movable contact plate has a snap-back mechanism including a deformation spring.

[0004] Moreover, in such a conventional pressure switch, when the working plate rotates about the fulcrum by increasing or decreasing the pressure applied to the bellows, the movable contact plate moves via the working shaft that follows the movement of the working plate. Thereby, the movable contact plate alternately connects the movable contact to one or two fixed contacts, and the microswitch is reversed.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Utility Model Publication No. 50-9571

[0008] Patent Document 2: Japanese Utility Model Publication No. 61-193647 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] However, in the conventional pressure switches described in Patent Documents 1 and 2, on the main body, a pressure increase side stopper and a pressure decrease side stopper that restrict the rotational movement of the working plate are provided at a predetermined interval in the vertical direction near the end of the lateral side portion of the working plate (only the latter is provided in Patent Document 1). And, in the case where an excessive pressure is applied to the bellows, the working plate is held by the fulcrum provided on the main body and the pressure increase side stopper provided above the side portion inside the main body, thereby preventing the elongation of the bellows.

[0011] However, in such a conventional pressure switch, when the pressure applied to the bellows further increases, the bellows elongates while tilting, so that the working plate of the main body may tilt. As a result, the working plate whose supporting relationship with the main body is lost is pushed up by the lower bellows while the end of the horizontal side portion is tilted downward, so that the end of the horizontal side portion may disengage from the pressure drop side stopper and fall off toward the bottom plate. In this case, not only the bellows may be damaged due to the detachment of the working plate, but also the leakage of a pressure medium such as a refrigerant may occur.

[0012] An object of the present invention is to provide a pressure switch that can improve the pressure resistance by preventing the detachment of a working plate even when an excessive pressure is applied to a pressure follower, thereby suppressing the breakage of the pressure follower and preventing the leakage of a pressure medium.

[0013] Solution to the problem

[0014] The pressure switch of the present invention includes, in a main body: a pressure follower; a working plate that abuts against the pressure follower and rotates about a fulcrum provided in the main body by the expansion and contraction of the pressure follower; a spring that opposes the movement of the working plate; a working shaft that follows the movement of the working plate; and a movable contact plate that makes a movable contact contact and separate from a fixed contact by the movement of the working shaft. The working plate has: a first side portion that abuts against the pressure follower; and a second side portion that is continuous with one end side of the first side portion via a bent portion. In the main body, a limit shaft parallel to the axial direction of the fulcrum near the first side portion of the working plate is provided. An anti-offset stopper is provided on the working plate, and the anti-offset stopper is located on the other end side of the first side portion with respect to the limit shaft. When an excessive pressure is applied to the pressure follower, the movement of the working plate is restricted by the anti-offset stopper abutting against the limit shaft.

[0015] According to the present invention described above, even when an excessive pressure is applied to the pressure follower and the supporting relationship between the working plate and the main body is lost due to the breakage of the fulcrum, since it is pushed up by the lower pressure follower while the end of the first side portion is tilted downward, the detachment of the working plate toward the bottom plate can be prevented by the anti-offset stopper abutting against the limit shaft, the breakage of the main body and the pressure follower can be suppressed, and the pressure resistance can be improved.

[0016] At this time, preferably, the limit shaft is provided at a position on the opposite side of the first side portion of the working plate from the pressure follower, and this position is on the other end side of the first side portion with respect to the fulcrum across the abutting position of the pressure follower and is closer to the bent portion side of the working plate than the anti-offset stopper.

[0017] According to this structure, even when an excessive pressure is applied to the pressure follower and the working plate loses its supporting relationship with the main body due to the breakage of the fulcrum, the anti-offset stopper can reliably abut against the limit shaft, thereby reliably preventing the above-mentioned working plate from falling off, reliably suppressing damage to the main body and the pressure follower, and further improving the pressure resistance.

[0018] Alternatively, a reset plate may be further provided. The reset plate is disposed along the surface of the working plate on the side opposite to the pressure follower side, has a bent portion at the free end, and is press-fitted to the first side portion of the working plate using a rivet. The rivet functions as the anti-offset stopper by engaging with the limit shaft.

[0019] According to this structure, the rivet for fixing the reset plate can be reused as the anti-offset stopper, so that the effort and cost of setting the stopper can be saved.

[0020] Moreover, the working plate may have a cut-up portion protruding toward the arrangement side of the limit shaft at the first side portion, and the cut-up portion functions as the anti-offset stopper.

[0021] According to this structure, the anti-offset stopper can be simply formed by only forming a cut-up portion protruding toward the arrangement side of the limit shaft at the first side portion of the working plate. In addition, there is no need to provide the anti-offset stopper in the form of other components, and the number of components can be reduced.

[0022] In addition, for example, a screw for adjusting the reset position of the working plate may be further provided, and the range of the rotational movement is restricted by the reset position adjustment performed by the screw on the working plate.

[0023] According to this structure, the rotational movement of the working plate is restricted by the reset position adjustment based on the screw, and the inclination becomes smaller. Therefore, it is more difficult for the working plate to fall off toward the bottom plate.

[0024] Advantages of the Invention

[0025] According to the pressure switch of the present invention, even when an excessive pressure is applied to the pressure follower, the pressure resistance can be improved by preventing the working plate from falling off, thereby suppressing damage to the pressure follower and preventing leakage of the pressure medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a cross-sectional view showing a compression switch of an embodiment.

[0027] Figure 2 It is a cross-sectional view showing the operating state of the compression switch of the embodiment.

[0028] Figure 3 It is a cross-sectional view of a compression switch showing a modified example.

[0029] Figure 4 It is a cross-sectional view showing the operating state of the compression switch in the modified example.

[0030] In the figure:

[0031] 1—Pressure switch; 2—Main body; 2a—Pivot point; 3—Bellows (pressure follower); 4—Working plate; 4a—Longitudinal side portion (second side portion); 4b—Transverse side portion (first side portion); 4c—Bending portion; 5—Spring; 6—Working shaft; 7—Limit shaft; 9—Anti-offset stopper; 10—Microswitch; 11—Movable contact plate; 12A, 12B—Fixed contacts; 13—Movable contact; 14—Deformation spring; 20—Reset plate; 21—Rivet; 22—Screw. Detailed implementation mode

[0032] Refer to Figure 1 and Figure 2 to describe the pressure switch of the implementation mode of the present invention. As Figure 1 and Figure 2 shown, the pressure switch 1 of the present implementation mode includes: a box-shaped main body 2 that constitutes the outer contour of the housing; a bellows 3 as a pressure follower, which is disposed at the bottom of the main body 2; and an L-shaped working plate 4 that rotates about the pivot point 2a by the expansion and contraction of the bellows 3.

[0033] The working plate 4 is in an L shape having a longitudinal side portion 4a as the second side portion and a transverse side portion 4b as the first side portion in a state where the first side portion on one side where the bellows 3 abuts is arranged in the horizontal direction and the second side portion on the other side is arranged in the vertical direction perpendicular to the first side portion. That is, the longitudinal side portion 4a and the transverse side portion 4b of the working plate 4 are formed in an L shape bent starting from the bending portion 4c. The bellows 3 is disposed in contact with the lower part of the transverse side portion 4b of the working plate 4. In addition, a spring 5 that opposes the movement of the working plate 4 and a working shaft 6 that follows the movement of the working plate 4 are engaged with the longitudinal side portion 4a of the working plate 4. In addition, in Figure 2 for convenience, the spring 5 and the working shaft 6 are omitted.

[0034] In this pressure switch 1, one end side of the working shaft 6 is engaged with the longitudinal side portion 4a of the working plate 4, and the other end side is engaged with the movable contact plate 11 constituting the microswitch 10. Further, the microswitch 10 includes, for example, two fixed contacts 12A and 12B and a movable contact 13 disposed between them. In the microswitch 10, the movable contact 13 is disposed at the free end portion of the movable contact plate 11 with respect to the fixed contacts 12A and 12B. The movable contact plate 11 has a rapid reverse mechanism including a deformation spring 14. The movable contact plate 11 receives the operation of the working plate 4 via the working shaft 6, whereby the movable contact 13 is brought into contact with and separated from the fixed contacts 12A and 12B.

[0035] Moreover, in such a pressure switch 1, when the working plate 4 rotates about the fulcrum 2a by increasing or decreasing the pressure applied to the bellows 3, the movable contact plate 11 operates via the working shaft 6 following the operation of the working plate 4. Thereby, the movable contact plate 11 selectively connects the movable contact 13 between one or two fixed contacts 12A and 12B, and the microswitch 10 reverses.

[0036] Further, in the pressure switch 1, on the main body 2, a pressure increase side stopper 2b and a pressure decrease side stopper 2c that restrict the rotational movement of the working plate 4 are provided at a predetermined interval in the vertical direction near the end portion of the lateral side portion 4b of the working plate 4. Moreover, in the case where an excessive pressure is applied to the bellows 3, the working plate 4 is held by the fulcrum 2a provided on the main body 2 and the pressure increase side stopper 2b provided above the side portion inside the main body 2, thereby preventing the elongation of the bellows 3.

[0037] Here, in a conventional pressure switch, when the pressure applied to the bellows further increases, since the bellows elongates while tilting, there is a case where the working plate of the main body tilts. Moreover, the working plate whose supporting relationship with the main body is lost is pushed up by the lower bellows in a state where the end portion of the lateral side portion tilts downward, and thus the end portion of the lateral side portion sometimes detaches from the pressure decrease side stopper and falls off toward the bottom plate. In this case, not only the bellows is damaged due to the detachment of the working plate, but also there is a possibility of leakage of a pressure medium such as a refrigerant.

[0038] Therefore, the pressure switch 1 of the present embodiment includes: a limit shaft 7 provided in a direction parallel to the axial direction of the fulcrum 2a near the working plate 4 inside the main body 2; and an anti-offset stopper 9 provided at a position on the working plate 4 closer to the end portion of the lateral side portion 4b than the limit shaft 7. Moreover, as Figure 2 shown, when an excessive pressure is applied to the bellows 3 and the fulcrum 2a is damaged, the anti-offset stopper 9 abuts against the limit shaft 7.

[0039] Specifically, the limit shaft 7 is arranged at a position on the opposite side of the bellows 3 of the lateral side 4b of the working plate 4 in the main body 2, and is arranged at the other end side of the lateral side 4b relative to the abutment position of the bellows 3 separated by the fulcrum 2a, and is arranged at a position closer to the bent portion 4c side of the working plate 4 than the anti-deviation stopper 9.

[0040] According to the present embodiment described above, even when excessive pressure is applied to the bellows 3 and the supporting relationship between the working plate 4 and the main body 2 disappears due to the destruction of the fulcrum 2a, the end of the lateral side portion 4b is pushed up by the bellows 3 below while being tilted downward. Therefore, the anti-deviation stopper 9 abuts against the limit shaft 7, thereby preventing the working plate 4 from falling off toward the bottom plate, thereby suppressing damage to the main body 2 and the bellows 3 and improving the pressure resistance.

[0041] In addition, the limit shaft 7 is arranged at a position on the opposite side of the working plate 4 in the main body 2 to the bellows 3, and is arranged at a position on the diagonal line relative to the fulcrum 2a and closer to the bent portion 4c of the working plate 4 than the anti-deviation stopper 9 which is above the lateral side 4b of the working plate 4. Therefore, even if excessive pressure is applied to the bellows 3 and the working plate 4 of the main body 2 is tilted due to the bellows 3 tilting and stretching, the anti-deviation stopper 9 can reliably abut against the limit shaft 7, thereby reliably preventing the above-mentioned working plate 4 from falling off and improving the pressure resistance. As a result, the bellows 3 can be reliably suppressed from being damaged and the leakage of the pressure medium can be prevented.

[0042] In addition, although not shown in the figure, the work plate 4 may also be formed with a cut-and-raised portion protruding toward the side where the limit axis 7 is arranged on the lateral side portion 4b, so that the cut-and-raised portion functions as an anti-deviating stopper. In this case, there are the following advantages: the anti-deviating stopper can be simply formed by only forming the cut-and-raised portion protruding toward the inner side on the lateral side portion 4b of the work plate 4, and the anti-deviating stopper does not need to be provided with other components, which can reduce the number of components.

[0043] In addition, the pressure switch of the present invention is not limited to the above-mentioned embodiment. Figure 1 , Figure 2 The corresponding parts are marked with the same symbols. Figure 3 , Figure 4 As shown, it is also possible to further include a reset plate 20, which is arranged along the upper part of the working plate 4, has a bent portion 20a at the free end, and is crimped to the horizontal side portion 4b of the working plate 4 using a rivet 21. In addition, for convenience, the Figure 3 Spring 5 and Figure 4 The spring 5 and the working shaft 6 in it.

[0044] In this case, the rivet 21 functions as an anti-offset stopper by engaging with the limit shaft 7. In addition, although not shown here, the working plate 4 may also have a cut-up portion protruding inward at the horizontal side portion 4b, and the cut-up portion functions as an anti-offset stopper.

[0045] According to the above modification example, there is also a reset plate 20 that is pressed against the horizontal side portion 4b of the working plate 4 by the rivet 21. Since the rivet 21 for fixing the reset plate 20 can be used as an anti-offset stopper, in addition to the effects of the above-described embodiment, it is also possible to save the effort and cost of setting the stopper.

[0046] As described above, the embodiments of the present invention have been described in detail with reference to the drawings, but the specific structure is not limited to these embodiments, and design changes and the like within the scope not departing from the gist of the present invention are also included in the present invention.

Claims

1. A pressure switch having within a main body: a pressure follower; a working plate that abuts against the pressure follower and rotates about a fulcrum provided on the main body by the expansion and contraction of the pressure follower; a spring that opposes the movement of the working plate; a working shaft that follows the movement of the working plate; and a movable contact plate that causes a movable contact to contact and separate from a fixed contact by the movement of the working shaft. The pressure switch is characterized in that: The working plate has: a first side portion that abuts against the pressure follower; and a second side portion that is continuous with one end side of the first side portion via a bent portion. Within the main body, a limit shaft is provided that is parallel to the axial direction of the fulcrum near the first side portion of the working plate. On the working plate, an anti-offset stopper is provided, and the anti-offset stopper is located on the other end side of the first side portion with respect to the limit shaft. In the case where an excessive pressure is applied to the pressure follower, the movement of the working plate is restricted by the anti-offset stopper abutting against the limit shaft.

2. The pressure switch according to claim 1, characterized in that: The limit shaft is provided at a position on the opposite side of the first side portion of the working plate from the pressure follower, and this position is on the other end side of the first side portion with respect to the fulcrum across the abutting position of the pressure follower, and is a position closer to the bent portion side of the working plate than the anti-offset stopper.

3. The pressure switch according to claim 1 or 2, characterized in that: It further includes a reset plate that is disposed along the surface of the working plate on the side opposite to the pressure follower side, and has a bent portion at the free end and is press-fitted to the first side portion of the working plate using a rivet. The rivet functions as the anti-offset stopper by being locked with the limit shaft.

4. The pressure switch according to claim 2, characterized in that: The working plate has a cutout portion that protrudes toward the side where the limit shaft is disposed on the first side portion. The cutout portion functions as the anti-offset stopper.

5. The pressure switch according to claim 3, characterized in that: The working plate has a cutout portion that protrudes toward the side where the limit shaft is disposed on the first side portion. The cutout portion functions as the anti-offset stopper.

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