Pressure-responsive switch

Abstract

The present invention aims to provide a pressure-responsive switch that ensures sufficient displacement of the operating member and operates stably. [Solution] The pressure-responsive switch 100 comprises a holding portion 65 having a low-pressure chamber 76 and a high-pressure chamber 77, a diaphragm 61 formed in an overall dome shape from a thin circular metal plate, an operating shaft 62, and a lever 4a for switching the conductivity state of the switch component 4. The diaphragm 61 comprises a first bulge portion 91 formed between the central portion 61a and the radially outward outer peripheral edge portion 61b and bulging upward Z1, a second bulge portion 92 formed between the first bulge portion 91 and the central portion 61a and bulging upward Z1, a first valley portion 94 recessed at the boundary between the first bulge portion 91 and the second bulge portion 92, and a second valley portion 95 recessed at the boundary between the second bulge portion 92 and the central portion 61a. The first bulge portion 91 and the second bulge portion 92 abut against the pressure-receiving portion 64.

Description

[Technical Field]

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

[0002] Conventionally, pressure-responsive switches using a diaphragm as a pressure-sensitive part have been known (see, for example, Patent Document 1). As shown in FIG. 1 of Patent Document 1, the pressure switch (pressure-responsive switch) described in Patent Document 1 includes a diaphragm, and a first shaft portion (actuating member) that abuts against the central portion of the diaphragm. In this pressure switch, the first shaft portion moves in accordance with the displacement of the diaphragm that receives pressure. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2021-26814 [Patent Document 2] Japanese Unexamined Patent Publication No. 7-167299 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In the field of pressure-responsive switches described above, there are cases where it is required to handle a wide range of pressures from low pressure to high pressure for the pressure to be detected. In this case, it is required to increase the displacement amount of the actuating member (hereinafter sometimes referred to as achieving a longer stroke) and to move the actuating member uniformly (proportionally) in accordance with changes in pressure. Regarding this point, for the pressure switch described in Patent Document 1, the following configuration may be considered, for example. First, the diaphragm is formed into a dome shape convex toward the low pressure chamber side shown in FIG. 1 of Patent Document 1 in a natural state before installation. Then, the top of the diaphragm is previously pressed by the first shaft portion to be deformed into a collapsed initial compressed state, and this initial compressed state is used for pressure detection.

[0005] The maximum displacement (stroke) of the first shaft portion 51 is the sum of the displacement from the initial compressed state to the state before pressing, and the displacement until the diaphragm 44 reaches its maximum extension state, which is the limit of displacement due to the elastic deformation inherent in the material of the diaphragm 44 itself. Since the amount of elastic deformation due to the elasticity inherent in the material of the diaphragm 44 is not large, increasing the initial compression amount can be considered in order to increase the stroke length. However, in this configuration, the entire diaphragm 44 will include a region in which it reverses significantly in the opposite direction to the direction in which it was previously pressed, between the initial compressed state and the maximum extension state. This large reversal movement occurs in a very short time and results in an extremely large displacement in response to changes in pressure. For this reason, if pressure detection is started in the initial compressed state, it is not possible to move the operating member uniformly (proportionally) in response to changes in pressure, making it difficult to configure a pressure-sensitive switch that can handle a wide range of pressures.

[0006] In this regard, it is conceivable to use a ripple-type diaphragm 1 as shown in Figure 1 of Patent Document 2. The ripple-type diaphragm 1 is made of synthetic resin or the like and has a shape in which multiple concentric convex portions 3 and concave portions 4 are connected in the radial direction. In this configuration, the ripple-type diaphragm 1 is easily deformed in a direction in which each part closes the concave portions 4, for example, and the large reversal movement described above is easily avoided. However, in the ripple-type diaphragm 1, since multiple concentric convex portions 3 and concave portions 4 are arranged in a row, there is a tendency for variations in the way displacement occurs when high pressure is applied, and there are issues with pressure resistance performance. In addition, in this configuration, it is also conceivable that the diaphragm may displace so as to cover the operating member when the diaphragm comes into contact with the operating member. In this case, the contact area between the diaphragm and the operating member will vary, so the force applied from the diaphragm to the operating member will vary, making it difficult to stabilize the operation of the operating member.

[0007] The present invention aims to provide a pressure-responsive switch that ensures sufficient displacement of the operating member and operates stably. [Means for solving the problem]

[0008] The pressure-sensitive switch of the present invention comprises a body having a low-pressure chamber and a high-pressure chamber; a diaphragm, a thin circular metal plate separating the low-pressure chamber and the high-pressure chamber, formed in an overall dome shape with the central part convex toward the low-pressure chamber side and displaceable toward the high-pressure chamber side or the low-pressure chamber side; an operating member having a pressure-receiving part that contacts the diaphragm from the low-pressure chamber side and moves in accordance with the displacement of the diaphragm; and a switching means that switches the conductive state of the switch in accordance with the movement of the operating member, wherein the diaphragm The device comprises: a first bulge formed between the central portion and the radially outward outer periphery portion and bulging toward the low-pressure chamber; a second bulge formed between the first bulge and the central portion and bulging toward the low-pressure chamber; a first valley provided at the boundary between the first bulge and the second bulge portion and recessed toward the high-pressure chamber; and a second valley provided at the boundary between the second bulge and the central portion and recessed toward the high-pressure chamber, wherein the first bulge and the second bulge are provided so as to be in contact with the pressure-receiving portion.

[0009] According to this invention, by forming the diaphragm from a metal material into an overall dome shape with the central part protruding towards the low-pressure chamber, for example, the following can be done. That is, the central part of the diaphragm is pressed and deformed by the pressure-receiving part of the operating member, and by starting the use of the pressure-responsive switch with this state as the initial compressed state, the height of the diaphragm can be used to increase the stroke length of the operating member. Furthermore, with this configuration, the posture of the first bulge and second bulge of the diaphragm can be reversed starting from the first valley and second valley. That is, a part of the diaphragm can be partially reversed. For this reason, for example, the following can also be done. That is, when the diaphragm is brought into the initial compressed state, the overall dome shape is maintained, while the first bulge and second bulge are displaced towards the high-pressure chamber. Then, as the pressure rises, the first bulge and second bulge are gradually reversed in that order, and the conductivity state of the switch is switched when both the first and second bulges are completely reversed. By limiting the diaphragm's reversal to a partial reversal in this manner, it is possible to increase the stroke length of the operating member while suppressing the large, rapid reversal of the entire diaphragm. This makes it easier to match the rate of pressure change with the rate of diaphragm displacement change, allowing for precise setting of the pressure at which the switch's conductivity changes. Furthermore, since the diaphragm is formed as a dome shape from a thin, circular metal plate, its pressure resistance can be improved compared to conventional diaphragms formed in a wave shape from synthetic resin or the like. Therefore, it is possible to provide a pressure-sensitive switch that ensures sufficient displacement of the operating member and operates stably.

[0010] Furthermore, the pressure-receiving portion is provided so as to face and be in contact with the plate surface of the diaphragm facing the low-pressure chamber side, and comprises a first projection that faces the central portion and protrudes toward the proximity side toward the plate surface, a second projection that protrudes toward the proximity side from a position that surrounds the first projection in an annular shape, and an intermediate region extending between the first projection and the second projection, wherein the protruding end of the first projection is located toward the proximity side relative to the protruding end of the second projection, and at least a part of the intermediate region is located toward the opposite, spaced-away side relative to the protruding end of the second projection.

[0011] According to this invention, for example, when the operating member is moved to the proximity side and brought into contact with the diaphragm, the first projection of the pressure-receiving part first comes into contact with the diaphragm. When the operation of the pressure-responsive switch is started with this state as the initial compression state, the diaphragm is displaced toward the low-pressure chamber side due to the change in pressure, and the diaphragm comes into contact with the second projection after the first projection, and then with the intermediate region. At this time, at least a part of the intermediate region is located on the side away from the projection end of the second projection, so that space can accommodate the displaced diaphragm, and the diaphragm can be brought into close contact with the intermediate region. Furthermore, in this configuration, since the first projection of the pressure-receiving part first comes into contact with the diaphragm, it is easier to apply force from the pressure-receiving part to the diaphragm and easier to bring the diaphragm into close contact with the second projection and the intermediate region compared to a configuration in which the entire pressure-receiving part comes into contact with the diaphragm. This improves the contact between the pressure-receiving part and the diaphragm and stabilizes the operation of the operating member. In this process, the contact area between the pressure-receiving portion and the diaphragm may gradually increase. However, as described above, the diaphragm contacts the first and second protrusions before contacting the intermediate region.

[0012] Therefore, the effective pressure-receiving diameter, which is the maximum radius of the portion where the pressure-receiving part and the diaphragm come into contact, is the radial length from the first central projection to the second radially outward projection, and remains almost constant before and after the diaphragm comes into contact with the intermediate region. On the other hand, even from this state until the pressure on the high-pressure chamber side decreases and the diaphragm is displaced towards the high-pressure chamber side and returns to the initial compressed state, the effective pressure-receiving diameter remains almost constant. Therefore, the operating member can move while receiving an almost constant force from the diaphragm at any position during displacement, and its operating characteristics are less prone to variation. Thus, a pressure-responsive switch with improved operational stability can be provided.

[0013] Furthermore, it is preferable that the intermediate region is formed in an arc shape that is recessed on the separated side. With such a configuration, the arc shape of the intermediate region makes it easier to bring the dome-shaped diaphragm, which is being displaced towards the low-pressure chamber side, into even closer contact with the intermediate region. This improves the contact between the diaphragm and the pressure-receiving part, and improves the stability of the operation of the operating member.

[0014] Furthermore, it is preferable that the first bulge and the second bulge have a curvature that follows the intermediate region. With this configuration, since the first bulge and the second bulge have a curvature that follows the intermediate region, the first bulge and the second bulge can be aligned with the intermediate region and made to be in close contact. This further improves the contact between the diaphragm and the pressure-receiving portion.

[0015] Furthermore, it is preferable that the central portion of the diaphragm constitutes a third bulge that protrudes toward the low-pressure chamber, and that the third bulge is provided so as to be able to contact the first projection. With this configuration, when the operating member is moved toward the proximity side and brought into contact with the diaphragm, the first projection of the pressure-receiving portion first comes into contact with the third bulge. This ensures that the first projection can be reliably brought into contact with the central portion of the diaphragm. In addition, with this configuration, for example, compared to a configuration in which a planar portion of the diaphragm comes into contact with the first projection, the force per unit area applied by the operating member to the diaphragm can be increased. This allows the diaphragm to be smoothly displaced when it is brought to the initial compression state described above. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a pressure-responsive switch that ensures sufficient displacement of the operating member and operates stably. [Brief explanation of the drawing]

[0017] [Figure 1] (A) is a side view of a pressure-sensitive switch according to one embodiment, and (B) is a front view of the pressure-sensitive switch. [Figure 2]An exploded perspective view showing a partially disassembled state of the pressure-responsive switch shown in Fig. 1. [Figure 3] (A) is a perspective view showing an assembled main body, a reinforcing plate, and a diaphragm assembly, and (B) is a cross-sectional view obtained by cutting a part of the assembled main body, reinforcing plate, and diaphragm assembly. [Figure 4] A cross-sectional view of the diaphragm assembly cut along the axis of an operating shaft. [Figure 5] A cross-sectional view of a diaphragm in a natural state cut along the axis of an operating shaft. [Figure 6] A schematic diagram highlighting the outer shapes of an operating shaft and a diaphragm. [Figure 7] (A) is a side view showing an operating shaft abutting against a diaphragm immediately before an initial compression state, and (B) is a bottom view of the operating shaft. [Figure 8] (A) is a cross-sectional view showing a pressure-sensitive part in a state where an operating shaft is located at an upper point, (B) is a cross-sectional view showing the pressure-sensitive part in a state where the operating shaft is located at an intermediate point, (C) is a cross-sectional view showing the pressure-sensitive part in a state where the operating shaft is located at a lowermost point, and (D) is a cross-sectional view showing the pressure-sensitive part where a diaphragm is in an initial compression state. [Figure 9] (A) is a side view of an operating shaft, and (B) is a cross-sectional view showing a diaphragm in a state where the diaphragm is in close contact with the operating shaft. [Figure 10] (A) is a side view showing an example of an operating shaft provided with a flat pressure-receiving part, and (B) is a cross-sectional view showing a state where a diaphragm is in close contact with the operating shaft shown in Fig. 10(A). MODE FOR CARRYING OUT THE INVENTION

[0018] An embodiment of a pressure-sensitive switch will be described below with reference to Figures 1 to 10. The pressure-sensitive switch 100 according to this embodiment is used, for example, as a switch that operates by detecting the fluid pressure P in a compressor or piping (not shown) in the refrigeration cycle of refrigeration equipment such as air conditioners. As shown in Figure 1(A), the pressure-sensitive switch 100 comprises a frame 1, an operating part 2, a pressure adjustment mechanism 3, a switch component 4 (switch), and a diaphragm assembly 6.

[0019] In the drawings, the extension and retraction direction of the range spring 31, which will be described later, is indicated by the arrow Z and labeled "up and down direction Z". One side of the up and down direction Z is labeled "upper Z1", and the other side is labeled "lower Z2". The horizontal direction is indicated by the arrows X and Y, labeled "front and back direction X" and "width direction Y", respectively. One side of the front and back direction X is labeled "front X1", and the other side is labeled "rear X2". These definitions of directions are for illustrative purposes only and do not necessarily limit the direction of each part of the pressure-sensitive switch 100 during manufacturing or use. Also, in the drawings, some symbols may be omitted to avoid complexity.

[0020] As shown in Figure 1(A), the frame 1 is formed in a roughly rectangular hollow shape in side view by connecting the main body 10 and the reinforcing plate 14 to each other, and houses the operating part 2, the pressure adjustment mechanism 3, and the switch component 4 inside. The switch component 4 is a mechanical switch that switches the conductive state of contacts (not shown) by driving the lever 4a (switching means) shown in Figure 1(A). As shown in Figure 1(B), the switch components 4 are arranged in pairs on one side and the other side in the width direction Y, forming a dual-type microswitch 5. Note that the microswitch 5 is not limited to a dual type and may be composed of a single switch component 4. The diaphragm assembly 6 is fixed to the main body 10 by the first fixing screw 7 on the lower side Z2 and outside of the main body 10. Note that if the microswitch 5 is composed of a single switch component 4, then the diaphragm assembly 6 is also composed of a single unit corresponding to the single switch component 4.

[0021] In the pressure-sensitive switch 100 configured in this way, when the joint 70 of the diaphragm assembly 6 (described later) receives pressure P from a compressor, piping, etc., that pressure P acts on the pressure-sensitive part 60 (see Figure 4), which will be described later. The pressure-sensitive part 60, upon receiving pressure P, is displaced in a predetermined direction according to the pressure P (for example, in a direction along the axis L of the operating shaft 62 (see Figure 4), which will be described later). Then, as shown in Figure 1(A), the force F1 generated when the pressure-sensitive part 60 is displaced in the predetermined direction acts on the operating part 2. The operating part 2 receives the force F1 generated by the pressure-sensitive part 60, changes its direction (operates), converts it into a predetermined force, which is an operating force F2, and drives the lever 4a. The operation of this lever 4a switches the conductivity state of the switch component 4.

[0022] As an example, in this embodiment, the relationship between the lever 4a and the switch component 4 is as follows. That is, before using the pressure-sensitive switch 100, the lever 4a is pressed to the right side of the page in Figure 1(A), causing an unshown contact in the switch component 4 to conduct, and it is detected that the pressure P is low. On the other hand, when the pressure P rises to a predetermined value or higher, the lever 4a is displaced to the left side of the page in Figure 1(A), causing a different contact in the switch component 4 to conduct, and it is detected that the pressure P is high.

[0023] Next, the structure of each part of the pressure-responsive switch 100 will be described in detail. First, the frame 1 will be described. The frame 1 comprises a main body 10 and a reinforcing plate 14. As shown in Figure 2, the main body 10 is formed in a C-shape by bending a metal plate. The main body 10 comprises a vertical wall 11 extending in the vertical direction Z, an upper wall 12 extending from the upper end of the vertical wall 11 to the front side X1, and a lower wall 13 extending from the lower end of the vertical wall 11 to the front side X1. Vertical ribs 11a are formed at both ends of the vertical wall 11 in the width direction Y, projecting to the front side X1, thereby reinforcing the vertical wall 11. Multiple claw holes 11b that penetrate in the front-rear direction X are formed on the plate surface of the vertical wall 11. Upper ribs 12a are formed at both ends of the upper wall 12 in the width direction Y, projecting to the lower side Z2, thereby reinforcing the upper wall 12.

[0024] Lower ribs 13a are formed at both ends of the lower wall 13 in the width direction Y, projecting upward Z1 and reinforcing the lower wall 13. As shown in Figure 3(A), annular bulges 13b1 are formed on the plate surface of the lower wall 13, bulging downward Z2. As shown in Figure 2, a pair of bulges 13b1 are formed with spacing in the width direction Y. A through hole 13b is formed in the center of each bulge 13b1, penetrating in the vertical direction Z. The shaft portion 63 of the operating shaft 62 shown in Figure 4 is inserted through the through hole 13b. The lower end surface of the bulge 13b1 forms a flat surface facing downward Z2, and this flat surface constitutes an operating shaft stopper 13b2 that can contact the first surface 64a of the pressure receiving portion 64, which will be described later.

[0025] As shown in Figure 3(A), a fixing hole 13c that penetrates in the vertical direction Z and a plurality of mounting holes 13d are formed around the bulge 13b1. A second fixing screw 8 (shown only in Figure 3(B)), which will be described later, is inserted through the fixing hole 13c. On the other hand, a female thread 13d1 (shown only in Figure 3(B)) is formed on the inner circumferential surface of the mounting hole 13d, and the first fixing screw 7 is screwed into the female thread 13d1. The switch component 4 is assembled inside the main body 10 configured in this way.

[0026] Next, the reinforcing plate 14 will be described. The reinforcing plate 14 is a member that reinforces the main body 10, and as shown in Figure 2, it is formed in a C shape by bending a metal plate. The reinforcing plate 14 comprises a vertical plate 15 extending in the vertical direction Z, an upper plate 16 extending from the upper end of the vertical plate 15 to the rear side X2, and a lower plate 17 extending from the lower end of the vertical plate 15 to the rear side X2. Vertical ribs 15a are formed at both ends of the vertical plate 15 in the width direction Y, projecting to the rear side X2, thereby reinforcing the vertical plate 15. A rectangular hole 15b that penetrates in the front-to-back direction X is formed in the lower Z2 portion of the plate surface of the vertical plate 15. In addition, a first slit 15c and a second slit 15d extending in the vertical direction Z are formed on the plate surface of the vertical plate 15, and are arranged with a gap in the width direction Y.

[0027] A scale plate 85, as shown in Figure 1(B), is attached to the vertical plate 15 formed in this manner via screws 86. A third slit 87 communicating with the first slit 15c of the reinforcing plate 14 and a fourth slit 88 communicating with the second slit 15d of the reinforcing plate 14 are formed on the surface of the scale plate 85, and these extend in the vertical direction Z. As shown in Figure 2, upper ribs 16a protruding downward Z2 are formed at both ends of the upper plate 16 in the width direction Y, reinforcing the upper plate 16. Lower ribs 17a protruding upward Z1 are formed at both ends of the lower plate 17 in the width direction Y, reinforcing the lower plate 17.

[0028] Each lower rib 17a has an axial hole 17a1 that penetrates in the width direction Y. A support shaft 19 extending in the width direction Y is inserted through the axial hole 17a1. A through hole 17b that penetrates in the vertical direction Z is formed on the surface of the lower plate 17. This through hole 17b is positioned coaxially with the through hole 13b of the main body 10 described above, and the shaft portion 63 of the operating shaft 62 is inserted inside it. In addition, on the surface of the lower plate 17, a fixing hole (not shown) that penetrates in the vertical direction Z is formed in front of the through hole 17b X1.

[0029] This fixing hole is formed with a female thread at a position coaxial with the fixing hole 13c shown in Figure 2 of the main body 10 described above. The second fixing screw 8 (see Figure 3(B)) inserted into the fixing hole 13c is screwed into the female thread. Then, claw portions 18 that protrude to the rear side X2 are formed at the rear ends of the upper plate 16 and the lower plate 17. The claw portions 18 are inserted into the claw holes 11b of the main body 10. Then, by crimping and bending the claw portions 18, the reinforcing plate 14 becomes one with the main body 10.

[0030] Next, the operating unit 2 will be described. As shown in Figure 2, the operating unit 2 comprises an operating plate 20 and a differential pressure plate 24. The operating plate 20 includes a receiving plate 21 extending in the front-rear direction X. A protrusion 21a is formed at the front end of the receiving plate 21, projecting forward X1. A projection 21b is formed on the plate surface of the receiving plate 21, projecting downward Z2 by bending a part of the plate surface downward Z2. The shaft portion 63 of the operating shaft 62 abuts against the projection 21b from downward Z2. Plate-shaped side portions 22 are formed at both ends of the receiving plate 21 in the width direction Y, rising upward Z1. An axial hole 22a is formed in the side portions 22, penetrating in the width direction Y. A plate-shaped pressing arm 23 is attached to the rear end of the receiving plate 21, rising upward Z1. With this configuration, the operating unit 2 has an overall L-shape.

[0031] The differential pressure plate 24 includes a plate-shaped front wall portion 25 extending in the width direction Y. A hole 25a is formed in the plate surface of the front wall portion 25, penetrating in the front-rear direction X. The protrusion 21a of the operating plate 20 is inserted into the hole 25a. A triangular plate-shaped biased portion 26 is formed at the upper end of the front wall portion 25, projecting upward Z1. A hook hole 26a is formed in the biased portion 26, penetrating in the front-rear direction X. Arm portions 27 extending in the front-rear direction X are formed at both ends of the front wall portion 25 in the width direction Y. An axial hole 27a penetrating in the width direction Y is formed at the rear end of the arm portion 27. The operating plate 20 and differential pressure plate 24, configured as described above, are connected to the reinforcing plate 14 by support shafts 19 that pass through the shaft holes 17a1, 22a, and 27a, respectively, with the central axes of the shaft holes 22a and 27a being coaxial with the central axis of the shaft hole 17a1 of the reinforcing plate 14.

[0032] Next, the pressure adjustment mechanism 3 will be described. As shown in Figure 1(A), the pressure adjustment mechanism 3 includes a biasing unit 30 that biases the operating unit 2, and an adjustment unit 33 that changes the biasing force of the biasing unit 30. The biasing unit 30 includes a range spring 31 extending in the vertical direction Z and a differential pressure spring 32 extending in the vertical direction Z. The range spring 31 is a compression spring and is positioned in the center of the front-rear direction X and the center of the width direction Y within the reinforcing plate 14, pressing the receiving plate 21 of the operating plate 20 downward Z2, thereby applying a biasing force F3 toward the operating unit 2 toward the downward Z2 direction.

[0033] The differential pressure spring 32 is a tension spring and is positioned on the front side X1 of the range spring 31. The lower end 32a of the differential pressure spring 32 is formed in a hook shape and is hooked into the hook hole 26a in the biased portion 26 of the differential pressure plate 24. As a result, the differential pressure plate 24 is pulled upward Z1, and this tensile force acts on the protrusion 21a of the operating plate 20 through the hole 25a of the differential pressure plate 24 shown in Figure 2. Therefore, the differential pressure spring 32 applies a biasing force F4 toward the upward Z1 direction to the operating portion 2.

[0034] As shown in Figure 1(A), the adjustment section 33 includes a range adjustment screw 34, a range spring receiving plate 35, a differential pressure adjustment screw 36, and a differential pressure spring receiving plate (not shown). The range adjustment screw 34 penetrates the upper wall 12 of the main body 10 and extends downward Z2 into the interior of the range spring 31. The range spring receiving plate 35 is formed in a plate shape that extends horizontally and is screwed onto the range adjustment screw 34 that penetrates its center. Furthermore, as shown in Figure 1(B), a first indicator needle 35a is formed protruding from the front X1 direction of the range spring receiving plate 35, and this first indicator needle 35a is inserted into a first slit 15c formed in the vertical plate 15 and a third slit 87 formed in the scale plate 85. As a result, the range spring receiving plate 35 cannot rotate around the axis of the range adjustment screw 34. Furthermore, this allows the range spring receiving plate 35 to be displaced in the axial direction of the range adjustment screw 34 as the range adjustment screw 34 rotates around its axis. Also, as the range spring receiving plate 35 is displaced in the axial direction, the first indicator needle 35a displaces the third slit 87 of the scale plate 85 in the axial direction, thereby enabling the display of the set value (set pressure, described later). As shown in Figure 1(A), the range spring 31 described above is installed between the range spring receiving plate 35 and the receiving plate 21. With this configuration, the distance in the vertical Z direction between the range spring receiving plate 35 and the receiving plate 21 can be changed by rotating the range adjustment screw 34 and changing the amount of rotation. By changing this distance, the amount of compression of the range spring 31 can be changed, and the biasing force F3 provided by the range spring 31 can be changed.

[0035] The differential pressure adjustment screw 36 penetrates the upper wall 12 of the main body 10 and extends downward Z2 into the interior of the differential pressure spring 32. A differential pressure spring receiving plate (not shown) is screwed onto the differential pressure adjustment screw 36, which penetrates its center. In addition, as shown in Figure 1(B), a second indicator needle 37 is formed protruding from the front X1 direction of the differential pressure spring receiving plate, and this second indicator needle 37 is inserted into a second slit 15d formed in the vertical plate 15 and a fourth slit 88 formed in the scale plate 85. As a result, the differential pressure spring receiving plate cannot rotate around the axis of the differential pressure adjustment screw 36. However, as a result, the differential pressure spring receiving plate can be displaced in the axial direction of the differential pressure adjustment screw 36 in conjunction with the rotation of the differential pressure adjustment screw 36 around its axis. Furthermore, as the differential pressure spring receiving plate is displaced in the axial direction, the second indicator needle 37 displaces the fourth slit 88 of the scale plate 85 in the axial direction, thereby enabling the display of the set on / off pressure difference value. A differential pressure spring 32, as shown in Figure 1(A), is installed between the differential pressure spring receiving plate and the biased part 26. With this configuration, the distance in the vertical Z direction between the differential pressure spring receiving plate and the biased part 26 can be changed by rotating the differential pressure adjustment screw 36 to change the amount of rotation. By changing this distance, the amount of tension of the differential pressure spring 32 can be changed, and the biasing force F4 provided by the differential pressure spring 32 can be changed.

[0036] In the operating unit 2 and pressure adjustment mechanism 3 configured as described above, if the sum of the force F1 and biasing force F4 shown in Figure 2 is greater than the biasing force F3, the operating plate 20 rotates (operates) in one direction (a predetermined direction) around the support shaft 19 in accordance with the displacement of the pressure-sensitive part 60, against the biasing force F3. On the other hand, if the sum of the force F1 and biasing force F4 shown in Figure 2 is less than the biasing force F3, the operating plate 20 rotates in the opposite direction to the one direction around the support shaft 19 due to the biasing force F3. These rotations generate an operating force F2 directed towards the front side X1 or the rear side X2. This operating force F2 causes the pressing arm 23 to press or release the lever 4a of the switch component 4. This pressing or release then switches the conductive state of the switch component 4.

[0037] With this configuration, the biasing unit 30 of the pressure adjustment mechanism 3 biases the operating unit 2 to the lower Z2 and upper Z1, thereby defining the pressure P at which the conductivity state of the switch component 4 switches. This pressure P is specifically referred to as the set pressure. In this embodiment, the adjustment unit 33 of the pressure adjustment mechanism 3 can freely change the biasing force F3 and biasing force F4 by the amount of rotation of the range adjustment screw 34 and the differential pressure adjustment screw 36, as described above. Therefore, the set pressure at which the conductivity state of the switch component 4 switches can be finely adjusted to various magnitudes, and the range from the upper limit to the lower limit of the detectable pressure P is wide.

[0038] Next, the diaphragm assembly 6 will be described. As shown in Figure 4, the diaphragm assembly 6 comprises a pressure-sensitive part 60, a holding part 65 (main body), and a joint 70. The pressure-sensitive part 60 is a part that is displaced in the vertical direction Z (a predetermined direction) in response to pressure P, and comprises a diaphragm 61 and an operating shaft 62 (operating member). The diaphragm 61 is made of, for example, a thin circular metal plate. As shown in Figure 5, in a natural state where no pressure P is applied, the diaphragm 61 is formed as an overall dome with the central part 61a convex upward Z1 (towards the pressure-receiving part 64, which will be described later), and extends in an intersecting direction that intersects the vertical direction Z (a predetermined direction). In this embodiment, the diaphragm 61 is made of a single plate, but the diaphragm 61 may be made by stacking multiple plates in the vertical direction Z.

[0039] As shown in Figure 4, the operating shaft 62 comprises a rod-shaped shaft portion 63 extending in the vertical direction Z, and a disc-shaped pressure-receiving portion 64 formed at the lower end of the shaft portion 63. The shaft portion 63 extends in the vertical direction Z by being inserted through the through hole 13b of the main body portion 10. The upper end of the shaft portion 63 abuts against the protruding portion 21b (see Figure 2) of the receiving plate 21 of the operating plate 20 from below Z2. As shown in Figure 4, the pressure-receiving portion 64 extends radially outward around the axis L of the shaft portion 63. The first surface 64a of the pressure-receiving portion 64, which faces upward Z1, is provided so as to be able to abut against the operating shaft stopper 13b2 formed on the bulge 13b1 of the main body portion 10 toward upward Z1 (low pressure side), and constitutes the contacted portion 69 in this embodiment. In this embodiment, the contact portion 69 is formed by the first surface 64a of the pressure receiving portion 64. However, it is not limited to this, for example, a flange or the like that may be provided on the upper side Z1 of the pressure receiving portion 64, projecting radially outward from the shaft portion 63, and this flange or the like may be used as the contact portion 69. The second surface 64b, which faces the lower side Z2 of the pressure receiving portion 64, is provided so as to be able to contact the upper side Z1 facing surface 61c of the diaphragm 61 (the plate surface facing the low-pressure chamber 76, which will be described later), in the vertical direction Z.

[0040] The holding portion 65 is the part that holds the diaphragm 61 to the outside of the main body portion 10, and comprises a lower holding member 66 (lower holding portion), an upper holding member 67 (upper holding portion), and a connecting member 68 (connecting portion). The lower holding member 66 is a bowl-shaped member that opens to the upper side Z1, and is also called a welded cap. The lower holding member 66 is positioned lower Z2 relative to the diaphragm 61. A holding hole 66a is formed in the center of the lower holding member 66, penetrating in the vertical direction Z, and the protruding portion 75 of the joint 70, which will be described later, is inserted through the holding hole 66a and held in that state. The upper holding member 67 is an annular member that extends in the circumferential direction around the axis L, and is also called a welded stopper. The upper holding member 67 is positioned upper Z1 relative to the diaphragm 61.

[0041] The lower Z2 portion of the inner edge of the upper holding member 67 is formed in an R shape, and this R-shaped portion constitutes a restricting portion 67a that can contact the outer peripheral edge 61b (outer periphery) of the diaphragm 61 from above Z1. The restricting portion 67a contacts the outer peripheral edge 61b of the diaphragm 61 during displacement, thereby restricting the displacement of the outer peripheral edge 61b of the diaphragm 61 upward Z1. The lower holding member 66 and the upper holding member 67, configured as described above, are welded to the diaphragm 61 over its entire circumference around the axis L while the outer peripheral edge 61b of the diaphragm 61 is clamped in the vertical direction Z. As a result, the lower holding member 66, the diaphragm 61, and the upper holding member 67 become one integrated unit.

[0042] The connecting member 68 is a cylindrical member extending in the axial direction L, and is also called a welded flange cap. The connecting member 68 is positioned above the upper holding member 67 at Z1. The lower end of the connecting member 68 is welded to the upper surface of the upper holding member 67. A flange portion 68a is formed at the upper end of the connecting member 68, projecting radially outward around the axial direction L. As shown in Figure 3(B), a mounting hole 68b is formed in the plate surface of the flange portion 68a, penetrating in the vertical direction Z. The mounting hole 68b is positioned coaxially with the mounting hole 13d of the lower wall 13 of the main body portion 10 described above. A first fixing screw 7 is inserted into this mounting hole 68b. The flange portion 68a is fixed to the lower surface (outer wall surface) of the lower wall 13 of the main body portion 10 by screwing this first fixing screw 7 into the female thread 13d1 of the mounting hole 13d of the main body portion 10. This fixing allows the connecting member 68 to connect the upper holding member 67, the diaphragm 61, and the lower holding member 66 to the main body 10. In this embodiment, the connecting member 68 and the upper holding member 67 are described as separate components, with the lower end of the connecting member 68 welded to the upper surface of the upper holding member 67. However, the connecting member 68 and the upper holding member 67 may be constructed as a single integrated part. That is, a flange portion is formed at the lower end of the connecting member 68 that protrudes toward the axis L (protrudes inward), and this flange portion may be made into a restricting portion 67a that can abut against the outer peripheral edge portion 61b (outer peripheral portion) of the diaphragm 61 from the upper side Z1. Alternatively, the radial thickness of the connecting member 68 may be increased so that the lower end surface becomes the restricting portion 67a.

[0043] The joint 70 is one means of transmitting pressure P to the pressure-sensitive part 60, and as shown in Figure 4, it is provided with an entry hole 71 that penetrates along the axis L. The joint 70 further includes a flared joint portion 73 with a male thread 72 formed on its outer circumference, a column portion 74 extending upward Z1 from the upper end of the flared joint portion 73, and a projection portion 75 protruding upward Z1 from the upper end of the column portion 74. The flared joint portion 73 is connected to the piping constituting the refrigeration cycle by screwing the male thread 72 into a flare nut (not shown). The column portion 74 is formed, for example, in a hexagonal column shape. The projection portion 75 is formed in a column shape with a smaller width dimension than the column portion 74 and is inserted into and held in the aforementioned holding hole 66a.

[0044] When the diaphragm assembly 6, formed as described above, is attached to the main body 10, the inside of the holding part 65 is divided by the diaphragm 61 into a low-pressure chamber 76 on the upper side Z1 (one side in a predetermined direction) and a high-pressure chamber 77 on the lower side Z2 (the other side in a predetermined direction). Specifically, the low-pressure chamber 76 is surrounded by the surface 61c of the diaphragm 61, the upper holding member 67, and the connecting member 68, and communicates with the inside of the frame 1 through the through hole 13b of the main body 10. The pressure in the low-pressure chamber 76 may be equal to atmospheric pressure, for example. The high-pressure chamber 77 is surrounded by the back surface 61d of the diaphragm 61 and the lower holding member 66, and is connected to a pipe through which high-pressure refrigerant flows, for example, via the introduction hole 71 of the joint 70. In this way, inside the holding part 65, the upper side Z1 with respect to the diaphragm 61 is the low-pressure chamber 76 side, and the lower side Z2 with respect to the diaphragm 61 is the high-pressure chamber 77 side.

[0045] Next, the shapes of the operating shaft 62 and the diaphragm 61 will be described in more detail. Figure 6 is a schematic diagram that emphasizes the external shapes of the pressure receiving part 64 (operating shaft 62) and the diaphragm 61. In Figure 6, assuming that the actual dimensions of the pressure receiving part 64 and the diaphragm 61 in the vertical direction Z are 1 and the actual dimensions in the width direction Y are 1, the dimensions in the vertical direction Z are stretched by 80 times and the dimensions in the width direction Y are stretched by 2.5 times to emphasize the external shapes. As shown in Figure 6, the pressure receiving part 64 is positioned on the upper side Z1 (low-pressure chamber 76 side) of the diaphragm 61 and can contact the diaphragm 61 from the upper side Z1. The second surface 64b of the pressure receiving part 64 includes a first protrusion 80, a second protrusion 81, and an intermediate region 82. The first projection 80 faces the central portion 61a of the surface 61c (plate surface) of the diaphragm 61 in the vertical direction Z, protrudes downward Z2 (the side approaching the surface 61c), and has a convex R shape on the downward Z2.

[0046] The second projection 81 is formed projecting downward Z2 from a position that encloses the first projection 80 in an annular shape along the circumferential direction around the axis L. The projection end 81a of the second projection 81 is located upward Z1 relative to the projection end 80a of the first projection 80. The intermediate region 82 extends between the first projection 80 and the second projection 81 and is formed in an arc shape that is recessed upward Z1 (the opposite side of the adjacent side). The uppermost portion 82a of the intermediate region 82 is located upward Z1 relative to the projection end 81a of the second projection 81. That is, at least a part of the intermediate region 82 is located upward Z1 relative to the projection end 81a of the second projection 81. Thus, the positional relationship of the first projection 80, the second projection 81, and the intermediate region 82 of the pressure receiving portion 64 is generally that of the first projection 80, the second projection 81, and the intermediate region 82, in order from downward Z2.

[0047] On the other hand, a bulge 90 is formed on a part of the diaphragm 61 that bulges toward the pressure receiving portion 64. The bulge 90 comprises a first bulge 91, a second bulge 92, and a third bulge 93. The first bulge 91 is formed between the central portion 61a of the diaphragm 61 and the radially outward outer peripheral edge portion 61b around the axis L. The first bulge 91 has an R shape that bulges toward the low-pressure chamber 76 and extends circumferentially over the entire circumference around the axis L. At least a part of this first bulge 91 is provided so as to be able to closely adhere to the intermediate region 82 of the pressure receiving portion 64.

[0048] The second bulge 92 is formed between the first bulge 91 and the central portion 61a. The second bulge 92 has an R-shape that bulges out toward the low-pressure chamber 76 and extends circumferentially around the entire circumference of the axis L. This second bulge 92 is provided so as to be able to fit tightly along the intermediate region 82 of the pressure-receiving portion 64. From the viewpoint of making it easier to fit the first bulge 91 and the second bulge 92 tightly to the intermediate region 82, it is preferable to set the curvature of the first bulge 91 and the second bulge 92 to correspond to the curvature of the intermediate region 82 and to have a curvature that follows the intermediate region 82. The third bulge 93 is the part that constitutes the top of the diaphragm 61, including the central portion 61a. The third bulge 93 has an R-shape that bulges out upward Z1 with a smaller curvature than the first bulge 91 and the second bulge 92.

[0049] The central portion 61a included in the third bulge 93 is positioned to be in contact with the protruding end 80a of the first projection 80 of the pressure-receiving portion 64, facing it in the vertical direction Z. At the boundary between the first bulge 91 and the second bulge 92 formed as described above, a first valley 94 is formed that is recessed toward the high-pressure chamber 77 side. Also, at the boundary between the second bulge 92 and the third bulge 93 (central portion 61a), a second valley 95 is formed that is recessed toward the high-pressure chamber 77 side. Furthermore, at the boundary between the outer peripheral edge 61b and the first bulge 91, a third valley 96 is formed that is recessed toward the lower side Z2. The first valley 94, the second valley 95, and the third valley 96 are formed in a groove shape and extend over the entire circumference in the circumferential direction around the axis L.

[0050] Next, the assembly of the pressure-sensitive switch 100 will be described. Figure 3(B) is a cross-sectional view of the main body 10, reinforcing plate 14, and a portion of the diaphragm assembly 6 after assembly is complete. First, as shown in Figure 3(B), the main body 10 and the reinforcing plate 14 are positioned so that their openings face each other in the front-rear direction X. Then, the reinforcing plate 14 is fitted into the main body 10. At this time, the claw portion 18 of the reinforcing plate 14 is inserted through the claw hole portion 11b of the main body 10 and bent by crimping. The main body 10 and the reinforcing plate 14 are then fixed to each other using the second fixing screw 8 shown in Figure 3(B). Although not explained here, when fixing the main body 10 and the reinforcing plate 14, the assembly of the operating part 2, pressure adjustment mechanism 3, and switch component 4 described above is also carried out at the same time.

[0051] Next, the diaphragm assembly 6 is installed on the lower side Z2 of the main body 10. First, with the flange portion 68a of the diaphragm assembly 6 in contact with the lower wall 13 of the main body 10, the first fixing screw 7 is inserted through the mounting hole 68b of the diaphragm assembly 6, and the first fixing screw 7 is screwed into the female thread 13d1 of the mounting hole 13d of the main body 10. When fixing in this manner, a mounting hole 17d (shown only in Figure 3(B)) coaxial with the mounting holes 13d and 68b may be formed in the lower plate 17 of the reinforcing plate 14, and the first fixing screw 7 may be inserted through the mounting hole 17d. With this, the assembly of the pressure-sensitive switch 100 is completed.

[0052] Next, the operation of the pressure-sensitive switch 100 will be described. When operating the pressure-sensitive switch 100, first, the set pressure, which is the pressure P at which the conductive state of the switch component 4 described above switches, is adjusted to match the arbitrary pressure P to be detected. This returns the pressure-sensitive switch 100 to its pre-use state. Specifically, the amount of rotation of the range adjustment screw 34 and the differential pressure adjustment screw 36 is adjusted to adjust the biasing force F3 of the range spring 31 and the biasing force F4 of the differential pressure spring 32. At this time, the operating shaft 62 is displaced downward Z2 via the receiving plate 21 of the operating plate 20, and an initial compressive force, which is a downward Z2 force, acts on the diaphragm 61 from the pressure-receiving part 64 shown in Figure 7(A). Due to the action of this initial compressive force, the central part 61a of the diaphragm 61, in particular, is displaced downward Z2 around the third bulge 93 shown in Figure 7(B). Then, when the operating shaft 62 (pressure receiving part 64) is positioned at the lowest point shown in Figure 8(D) corresponding to the set pressure, the displacement of the diaphragm 61 is completed, and the pressure-responsive switch 100 returns to its pre-use state.

[0053] The state of the diaphragm 61 before use is referred to as the initial compression state. In this embodiment, the central portion 61a of the diaphragm 61, which is included in the third bulge portion 93 of the diaphragm 61, is provided to be in contact with the protruding end 80a of the first protrusion 80 of the pressure receiving portion 64, facing it in the vertical Z direction, as described above. Therefore, as shown in Figures 7(A) and (B), when the diaphragm is brought into the initial compression state, the first protrusion 80 reliably contacts the central portion 61a of the diaphragm 61. With this configuration, for example, compared to a configuration in which a planar portion of the diaphragm 61 contacts the first protrusion 80, the force per unit area applied by the first protrusion 80 to the diaphragm 61 can be increased. As a result, when the diaphragm 61 is brought into the initial compression state, the diaphragm 61 can be smoothly displaced. Furthermore, this causes the diaphragm 61, which is subsequently subjected to pressure P, to displace starting from the displaced point, making it easier for it to come into close contact with the second protrusion 81 and intermediate region 82 of the pressure-receiving section 64.

[0054] When the diaphragm 61 is in its initial compressed state, a small gap S in the vertical direction Z is created between the diaphragm 61 and the pressure receiving section 64, as shown in Figure 8(D). The diaphragm 61 as a whole maintains a dome shape that is convex upward Z1, similar to the natural state described above. On the other hand, although not shown in the figure, at least a portion of the first bulge 91, second bulge 92, and third bulge 93, which are parts of the diaphragm 61, invert towards the high-pressure chamber 77, starting from the first valley 94 and second valley 95. In other words, the diaphragm 61 in its initial compressed state maintains its overall dome shape while partially inverting in a portion of it. At this time, the third bulge 93 is in close contact with the operating shaft 62.

[0055] The pressure-sensitive switch 100 in this state is installed in a pipe through which the refrigerant flows, and the operation of the pressure-sensitive switch 100 is started. In this embodiment, the pressure-sensitive switch 100 detects that the pressure P is low in the initial compression state. Immediately after the start of operation, when a fluid such as refrigerant flows into the high-pressure chamber 77 through the introduction hole 71 of the joint 70, the diaphragm 61 receives the pressure P and is displaced upward towards Z1 as shown in Figure 8(C). At this time, the gap S between the diaphragm 61 and the pressure-receiving part 64 that existed in the initial compression state becomes smaller, and the diaphragm 61 comes into contact with the pressure-receiving part 64 of the operating shaft 62 which is located at the lowest point.

[0056] Specifically, immediately after the start of operation as shown in Figure 8(C), the diaphragm 61 comes into contact with the second protrusion 81 of the pressure receiving section 64, in addition to the first protrusion 80 shown in Figure 9(A), which it was in contact with in the initial compressed state. The reason the diaphragm 61 comes into contact with the second protrusion 81 after the first protrusion 80 is that, as described above, the positional relationship between the first protrusion 80, the second protrusion 81, and the intermediate region 82 of the pressure receiving section 64 is that, from the bottom Z2, they are in the order of the first protrusion 80, the second protrusion 81, and the intermediate region 82.

[0057] Next, as the pressure P increases immediately after the start of operation, the diaphragm 61 is further displaced upward Z1. Along with this displacement, the operating shaft 62 is also displaced upward Z1. Then, the force F1 (see Figure 2) generated when the operating shaft 62 is displaced presses the protruding portion 21b of the receiving plate 21 of the operating part 2 upward Z1. The force F1 increases with the upward displacement of the operating shaft 62.

[0058] In other words, the sum of force F1 and biasing force F4 becomes greater than the biasing force F3, causing the actuation plate 20 to rotate in one direction around the support shaft 19. This rotation causes an actuation force F2 toward the left side of the paper to act on the lever 4a shown in Figure 1(A). As a result, the pressure on the lever 4a is released, and when the actuation shaft 62 is positioned at the midpoint shown in Figure 8(B), the conductivity of the switch component 4 is switched. In this way, the conductivity of the switch component 4 is switched in accordance with the movement of the actuation shaft 62. This switching causes the pressure-responsive switch 100 to detect that the pressure P is high.

[0059] Thus, from immediately after the start of operation shown in Figure 8(C) until the conduction state shown in Figure 8(B) is switched, the diaphragm 61 gradually comes into contact with the intermediate region 82 in addition to the first protrusion 80 and second protrusion 81 of the pressure receiving portion 64. Specifically, the first valley 94 of the diaphragm 61 comes into contact with the first valley contact point 83 of the pressure receiving portion 64 shown in Figure 9(A), and the first bulge 91 inverts to the upper side Z1 starting from this first valley 94, and as shown in Figure 9(B), the first bulge 91 comes into contact with the intermediate region 82, resulting in a tight seal.

[0060] Furthermore, the second valley 95 of the diaphragm 61 contacts the second valley contact point 84 of the pressure-receiving portion 64 shown in Figure 9(A), and the second bulge 92 inverts upward Z1 starting from this second valley 95, so that the second bulge 92 comes into contact with the intermediate region 82 as shown in Figure 9(B), resulting in a tight fit. In this way, the diaphragm 61 comes into contact with all of the pressure-receiving portion 64, including the first protrusion 80, the second protrusion 81, and the intermediate region 82, resulting in a tight fit. The operating shaft 62 is then positioned at the midpoint shown in Figure 8(B), and the conductivity of the switch component 4 is switched as described above. With this configuration, the height in the vertical direction Z of the diaphragm 61, which is formed in an overall dome shape, can be used to ensure sufficient displacement of the operating shaft 62, thereby enabling a longer stroke. Furthermore, from immediately after the start of operation as shown in Figure 8(C) until the conductivity state is switched as shown in Figure 8(B), the contact area between the pressure receiving part 64 and the diaphragm 61 gradually increases.

[0061] In this case, as shown in Figure 10(A), if the pressure-sensitive part 200 is configured with a pressure-receiving part 202 having a flat surface without a first protrusion 80, a second protrusion 81, and an intermediate region 82, and an operating shaft 201, then as shown in Figure 10(B), the gap S between the pressure-receiving part 202 and the diaphragm 300 is difficult to fill, and the contact point with the pressure-receiving part 202 when the diaphragm 300 is displaced is difficult to determine uniformly. Therefore, the effective pressure-receiving diameter, which is the maximum radius of the part where the pressure-receiving part 64 and the diaphragm 61 come into contact, tends to vary. As a result, the force applied from the diaphragm 300 to the operating shaft 201 is difficult to keep constant, and the operation of the operating shaft 201 becomes unstable.

[0062] On the other hand, in this embodiment, as described above, the diaphragm 61 comes into contact with all of the first protrusion 80, the second protrusion 81, and the intermediate region 82 of the pressure receiving portion 64, resulting in a tight fit. This eliminates the gap S and makes it easier to secure a sufficient contact area between the pressure receiving portion 64 and the diaphragm 61 (see Figure 9(B)). In this case, although the contact area between the pressure receiving portion 64 and the diaphragm 61 gradually increases, as described above, the diaphragm 61 has already come into contact with the first protrusion 80 and the second protrusion 81 before coming into contact with the intermediate region 82. Therefore, as shown in Figure 8(B), even if the contact area between the pressure receiving portion 64 and the diaphragm 61 increases, the position of the outer peripheral contact portion 61e, which is the radially outermost point of contact between the diaphragm 61 and the pressure receiving portion 64, will be approximately the same in the radial direction around the axis L as the position of the outer peripheral contact portion 61e of the diaphragm 61 immediately after the start of operation (outer peripheral contact portion 61e in Figure 8(C)), as shown by the dashed line A in Figure 8.

[0063] Therefore, the effective pressure-receiving diameter, which is the maximum radius of the portion where the pressure-receiving part 64 and the diaphragm 61 come into contact, is the radial length from the first protrusion 80 to the second protrusion 81 shown in Figure 9(A), and remains approximately constant before and after the diaphragm 61 comes into contact with the intermediate region 82. Consequently, the force applied from the diaphragm 61 to the operating shaft 62 tends to remain constant, and the operation of the operating shaft 62 becomes stable.

[0064] Furthermore, from immediately after the start of operation shown in Figure 8(C) until the conduction state switches as shown in Figure 8(B), the first bulge 91, the second bulge 92, and the third bulge 93 each invert toward the low-pressure chamber 76 side, but the overall shape of the diaphragm 61 remains almost unchanged as a dome shape convex upward Z1. In other words, the inversion of the entire diaphragm 61 is suppressed, and the inversion movement can be partially retained. Therefore, the sudden occurrence of a large inversion movement of the diaphragm 61 is suppressed. Moreover, since the first bulge 91, the second bulge 92, and the third bulge 93 are each divided into the first valley 94 and the second valley 95, the following can be achieved. That is, since the first bulge 91, the second bulge 92, and the third bulge 93 tend to invert sequentially without inverting all at once, it is easy to match the displacement ratio of the diaphragm 61 with the displacement ratio of the operating shaft 62. Therefore, the range from the upper to the lower limit of the pressure P detectable by the pressure-sensitive switch 100 can be widened, and the stability of the operation of the pressure-sensitive switch 100 can be improved. Furthermore, since the diaphragm 61 is formed from a thin metal disc, its pressure resistance can be improved compared to conventional diaphragms formed in a wave shape from synthetic resin or the like.

[0065] Furthermore, compared to the diaphragm 61 immediately after the start of operation, the contact area between the outer peripheral edge 61b of the diaphragm 61 and the restricting portion 67a of the upper holding member 67 is slightly larger when the operating shaft 62 is at the midpoint. However, by providing the restricting portion 67a, the displacement of the outer peripheral edge 61b of the diaphragm 61 to the upper Z1 by an unintended amount of displacement is suppressed.

[0066] If the pressure P increases further from this state, the diaphragm 61 will be displaced further upward Z1, and the operating shaft 62 will also be displaced upward Z1 along with this displacement. The amount of upward Z1 displacement of the operating shaft 62 is limited by the amount of displacement that the aforementioned protrusion 21a can displace within the hole 15b, and the position where this displaceable amount is maximum becomes the upper point of the operating shaft 62. However, if excessive pressure is applied, it is conceivable that the operating shaft 62 may be displaced beyond the amount of displacement that the protrusion 21a can displace within the hole 15b. In such a case, excessive deformation will occur in the diaphragm 61, so an operating shaft stopper 13b2 is provided on the main body 10. When excessive pressure is applied, the operating shaft 62 stops moving when the first surface 64a (contact portion 69) of the pressure-receiving portion 64 comes into contact with the operating shaft stopper 13b2 on the main body 10. This protects the diaphragm 61 even if excessive pressure is applied. The position of the operating shaft 62 is defined as the uppermost point. As shown in Figure 8(A), when the operating shaft 62 is at the upper point, the position of the outer peripheral contact point 61e of the diaphragm 61 is slightly radially inward in the radial direction of the operating shaft 62 compared to the position of the outer peripheral contact point 61e of the diaphragm 61 immediately after the start of operation, as indicated by the dashed line A. In other words, after the conductivity state of the switch component 4 is switched, as the diaphragm 61 is displaced upward Z1, the contact point between the diaphragm 61 and the pressure receiving portion 64 shifts towards the center, and the area of ​​the contact point becomes slightly smaller. However, as described above, the diaphragm 61 has a configuration that allows it to contact and be in close contact with all of the first protrusion 80, the second protrusion 81, and the intermediate region 82 of the pressure receiving portion 64, so the reduction in the area of ​​the contact point is easily suppressed.

[0067] Subsequently, as the pressure P decreases, the operating shaft 62 moves from the upper point toward the lower side Z2. That is, when the sum of the force F1 and biasing force F4 shown in Figure 2 becomes smaller than the biasing force F3, this biasing force F3 causes the operating plate 20 to rotate in the opposite direction to the direction around the support shaft 19. Due to these rotations, an operating force F2 acts on the lever 4a from the pressing arm 23 toward the right side of the paper in Figure 1(A). This action switches the conductivity state of the switch component 4, and the low pressure P is detected again.

[0068] As described above, according to this embodiment, by forming the diaphragm 61 from a metal material into an overall dome shape with the central portion 61a protruding towards the low-pressure chamber 76, for example, the following can be done. That is, the central portion 61a of the diaphragm 61 is pressed and deformed by the pressure-receiving portion 64 of the operating shaft 62 (operating member), and by starting the use of the pressure-responsive switch 100 with this state as the initial compression state, the height of the diaphragm 61 can be used to increase the stroke length of the operating shaft 62. Furthermore, with this configuration, the diaphragm 61 can reverse the orientation of the first bulge portion 91 and the second bulge portion 92, starting from the first valley portion 94 and the second valley portion 95. That is, a part of the diaphragm 61 can be partially reversed. For this reason, for example, the following can also be done. That is, when the diaphragm 61 is brought into the initial compression state, the overall dome shape is maintained, while the first bulge portion 91 and the second bulge portion 92 are displaced towards the high-pressure chamber 77.

[0069] Then, as the pressure P increases, the first bulge 91 and the second bulge 92 are gradually reversed in that order, and the conductivity of the switch component 4 (switch) is switched when both the first and second bulge 91 and the second bulge 92 are completely reversed. By limiting the reversal of the diaphragm 61 to a partial reversal in this way, it is possible to increase the stroke length of the operating shaft 62 while suppressing the large, rapid reversal of the entire diaphragm 61. Therefore, it is easy to match the rate of change in pressure P with the rate of change in the displacement of the diaphragm 61, and the set pressure can be set precisely. In addition, since the diaphragm 61 is formed in a dome shape from a thin circular metal plate, its pressure resistance can be improved compared to conventional diaphragms formed in a wave shape from synthetic resin or the like. Thus, it is possible to provide a pressure-responsive switch 100 that ensures sufficient displacement of the operating shaft 62 (operating member) and operates stably.

[0070] Furthermore, according to this embodiment, for example, when the operating shaft 62 is moved downward Z2 (proximity side) to contact the diaphragm 61, the first projection 80 of the pressure receiving part 64 first contacts the diaphragm 61. Then, with this state as the initial compression state, the operation of the pressure-responsive switch 100 is started. When the diaphragm 61 is displaced toward the low-pressure chamber 76 side due to the change in pressure P, the diaphragm 61 contacts the second projection 81 after the first projection 80, and then contacts the intermediate region 82. At this time, the uppermost part 82a of the intermediate region 82 is located upward Z1 (separation side) relative to the projection end 81a of the second projection 81, so that it can accommodate the displaced diaphragm 61 in that space and make the diaphragm 61 tightly close to the intermediate region 82. Furthermore, in this configuration, since the first protrusion 80 of the pressure-receiving portion 64 first contacts the diaphragm 61, it is easier to apply force from the pressure-receiving portion 64 to the diaphragm 61 and to bring the diaphragm 61 into close contact with the second protrusion 81 and the intermediate region 82, compared to a configuration in which the entire pressure-receiving portion 64 contacts the diaphragm 61. This improves the contact between the pressure-receiving portion 64 and the diaphragm 61 and stabilizes the operation of the operating shaft 62. In this case, the contact area between the pressure-receiving portion 64 and the diaphragm 61 gradually increases. However, as described above, the diaphragm 61 contacts the first protrusion 80 and the second protrusion 81 before contacting the intermediate region 82.

[0071] Therefore, the effective pressure-receiving diameter, which is the maximum radius of the portion where the pressure-receiving part 64 and the diaphragm 61 come into contact, is the radial length from the central first protrusion 80 to the radially outward second protrusion 81, and remains almost constant before and after the diaphragm 61 comes into contact with the intermediate region 82. On the other hand, even from this state until the pressure P on the high-pressure chamber 77 side decreases and the diaphragm 61 is displaced toward the high-pressure chamber 77 side and returns to the initial compression state, the effective pressure-receiving diameter remains almost constant. Therefore, the operating shaft 62 can move while receiving an almost constant force from the diaphragm 61 at any position during displacement, and its operating characteristics are less prone to variation. Thus, a pressure-responsive switch 100 with improved operational stability can be provided.

[0072] Furthermore, according to this embodiment, since the intermediate region 82 is formed in an arc shape, it is easier to bring the dome-shaped diaphragm 61, which is being displaced toward the low-pressure chamber 76, closer to the intermediate region 82. This improves the contact between the diaphragm 61 and the pressure-receiving portion 64, thereby improving the stability of the operation of the operating shaft 62.

[0073] Furthermore, according to this embodiment, since the first bulge 91 and the second bulge 92 have a curvature that follows the intermediate region 82, the first bulge 91 and the second bulge 92 can be aligned with the intermediate region 82 and made to be in close contact. This further improves the contact between the diaphragm 61 and the pressure-receiving portion.

[0074] Furthermore, according to this embodiment, when the operating shaft 62 is moved downward Z2 to contact the diaphragm 61, the first protrusion 80 of the pressure receiving portion 64 first contacts the third bulge portion 93. Therefore, the first protrusion 80 can be reliably brought into contact with the central portion 61a of the diaphragm 61. Also, with this configuration, for example, compared to a configuration in which a planar portion of the diaphragm 61 is brought into contact with the first protrusion 80, the force per unit area applied by the operating shaft 62 to the diaphragm 61 can be increased. As a result, when the diaphragm 61 is brought to the initial compression state described above, the diaphragm 61 can be smoothly displaced.

[0075] The embodiments described above are merely representative forms of the present invention, and the present invention is not limited thereto. That is, it can be implemented with various modifications without departing from the core principles of the present invention. As long as such modifications still possess the configuration of the pressure-sensitive switch 100 of the present invention, they are of course included within the scope of the present invention. For example, in this embodiment, a joint 70 is used as a member that transmits pressure P to the pressure-sensitive part 60, but a capillary may be used instead of the joint 70. That is, a temperature switch can be constructed by connecting a temperature-sensing tube to the diaphragm assembly 6 in the pressure-sensitive switch 100 of this embodiment via a capillary, and filling the closed space formed by the sensing member (pressure-sensitive part 60), the capillary, and the temperature-sensing tube with fluid. In this way, in a temperature switch using the pressure-sensitive switch 100 of this embodiment, the pressure-sensitive part 60 is displaced in the vertical direction Z in response to the pressure P inside the closed space which changes due to the temperature change detected by the temperature-sensing tube, and this force is transmitted to the lever 4a, thereby changing the conductivity state of the switch component 4.

[0076] Furthermore, in this embodiment, the pressure-responsive switch 100 is configured to include a pressure adjustment mechanism 3. However, even in a configuration in which the pressure adjustment mechanism 3 is omitted, the operating shaft 62 and diaphragm 61 of the present invention can still be applied. [Explanation of Symbols]

[0077] 4. Switch components (switches) 4a Lever (switching mechanism) 61a central part 61b Outer edge (outer periphery) 61 Diaphragm 62. Actuating shaft (actuating member) 64 Pressure-receiving section 65 Holding part (main body) 76 Low-pressure chamber 77 High-pressure chamber 91 First bulge 92 Second bulge 94 First Valley 95 Second Valley 100 Pressure-responsive switches

Claims

1. A main body having a low-pressure chamber and a high-pressure chamber, A thin, circular metal plate separates the low-pressure chamber and the high-pressure chamber, forming an overall dome shape with the central part convex towards the low-pressure chamber, and includes a diaphragm that is displaceable towards either the high-pressure chamber or the low-pressure chamber. An operating member having a pressure-receiving portion that contacts the diaphragm from the low-pressure chamber side and moves in accordance with the displacement of the diaphragm, A pressure-responsive switch comprising a switching means for switching the conductivity state of a switch in accordance with the movement of the operating member, The diaphragm comprises: a first bulge formed between the central portion and the radially outward outer periphery, bulging toward the low-pressure chamber; a second bulge formed between the first bulge and the central portion, bulging toward the low-pressure chamber; a first valley provided at the boundary between the first bulge and the second bulge, recessed toward the high-pressure chamber; and a second valley provided at the boundary between the second bulge and the central portion, recessed toward the high-pressure chamber. A pressure-responsive switch characterized in that the first bulge and the second bulge are provided so as to be in contact with the pressure-receiving portion.

2. The pressure receiving portion is provided so as to face and be in contact with the plate surface of the diaphragm facing the low-pressure chamber side, and comprises a first projection that faces the central portion and protrudes toward the proximity side toward the plate surface, a second projection that protrudes toward the proximity side from a position that surrounds the first projection in an annular shape, and an intermediate region extending between the first projection and the second projection. The protruding end of the first protrusion is located on the side closer to the protruding end of the second protrusion. The pressure-responsive switch according to claim 1, characterized in that at least a portion of the intermediate region is located on the opposite side of the distance from the protruding end of the second protrusion.

3. The pressure-responsive switch according to claim 2, characterized in that the intermediate region is formed in an arc shape that is recessed toward the separated side.

4. The pressure-responsive switch according to claim 3, characterized in that the first bulge and the second bulge have a curvature along the intermediate region.

5. The central portion of the diaphragm constitutes a third bulge that protrudes toward the low-pressure chamber. The pressure-responsive switch according to claim 2, characterized in that the third bulge is provided so as to be able to contact the first protrusion.

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