Pressure switch

Abstract

This pressure switch comprises: a metal pressure-resistant container; conductive terminals provided through the pressure-resistant container and fixed in an airtight and insulated state with respect to the pressure-resistant container; a contact mechanism electrically connected to the conductive terminals and provided inside the pressure-resistant container; a diaphragm that covers an opening portion of the pressure-resistant container and is attached to the pressure-resistant container in an airtight state, the diaphragm operating at or above a predetermined operation pressure and being capable of returning at a return pressure lower than the operation pressure; and a pressing member that opens and closes the contact mechanism by transmitting displacement due to the operation and return of the diaphragm. The pressing member includes a first pressing member fixed to the contact mechanism side and a second pressing member in contact with the diaphragm, and the first pressing member and the second pressing member are in contact with each other so as to be movable in a tilting direction. The pressing member opens and closes the contact mechanism by receiving the displacement of the diaphragm by the second pressing member, transmitting the displacement to the contact mechanism via the first pressing member, and pressing the contact mechanism.

Description

pressure switch

[0001] The present invention relates to a pressure switch that detects an increase or decrease in pressure inside a sealed container.

[0002] Conventionally, there has been a pressure switch in which a pressure plate is exposed inside a pressure vessel, and when the pressure rises or falls above a threshold, the pressure plate is displaced with a snap action, driving contacts to open or close an electric circuit.

[0003] For example, a typical example is a pressure switch used in automobiles, which is made by crimping a resin connector to a metal container that contains a diaphragm and switch mechanism that serves as the pressure receiver. The tip of the metal container has a hole in the center to receive gas or liquid, and a screw thread on its outer periphery, and is fixed by screwing the tip directly from the outside into a mounting hole drilled in the device to be pressure detected.

[0004] In this structure, the pressure switch's container needs to be strong enough to be screwed into the device that is to be detected, which requires the container to be thick and thread cutting. Also, because it is made up of multiple parts that mix resin and metal, multiple seal members must be provided at the boundaries between the resin and metal to achieve a sealed structure, which increases the number of parts and increases the manufacturing effort.

[0005] On the other hand, the present applicant has proposed a pressure switch with an airtight metal pressure-resistant container so that the entire switch can be placed inside the pressure container. This pressure switch has an airtight structure with the entire container made of thick metal so that it can be placed inside a pressure container used at high pressures. The switch mechanism has a structure with multiple contacts, and is further equipped with a fuse mechanism to cut off current in the event of an abnormal pressure rise. Therefore, for use in pressure detection in a relatively low pressure environment, the pressure resistance is excessive and the switch is too large. On the other hand, if the pressure switch structure is simply made smaller, the operating resistance of the moving parts of the switch mechanism, due to factors such as the tilt of the parts during operation, can become relatively large due to the influence of the machining accuracy and assembly accuracy of the parts, and this can lead to poor movement of the parts and the expected performance cannot be achieved.

[0006] JP 2002-260505 A Japanese Patent No. 7137250 A

[0007] The problem to be solved is to provide a sealed pressure switch that is compact, operates reliably, and is adaptable to a variety of mounting configurations.

[0008] The pressure switch of the present disclosure includes a metal pressure-resistant container, a conductive terminal that penetrates the pressure-resistant container and is fixed to the pressure-resistant container in an airtight and insulated state, a contact mechanism that is electrically connected to the conductive terminal and is provided inside the pressure-resistant container, a diaphragm that covers an opening of the pressure-resistant container and is airtightly attached to the pressure-resistant container, and that operates at a predetermined operating pressure or higher and can return at a return pressure lower than the operating pressure, and a pressing member that transmits displacement due to the operation and return of the diaphragm to open and close the contact mechanism. The pressing member includes a first pressing member fixed to the contact mechanism and a second pressing member that contacts the diaphragm, and the first pressing member and the second pressing member are in contact and movable in an inclined direction. The pressing member receives displacement of the diaphragm with the second pressing member and transmits it to the contact mechanism via the first pressing member, thereby pressing the contact mechanism to open and close the contact mechanism.

[0009] The pressure switch of the present disclosure has a structure that can absorb tilt that occurs during operation of the pressing member that transmits the displacement of the pressure receiving part to the contact mechanism. As a result, the pressure switch has a structure in which the pressing member that is prone to tilt due to its structure is divided, and the part where tilt is not tolerated is not affected by the tilt of other parts, which makes it possible to suppress the occurrence of operating resistance between parts that becomes a problem when miniaturizing.

[0010] FIG. 1 is a cross-sectional view of a pressure switch according to a first embodiment. FIG. 2 is a cross-sectional view for explaining the operating state of the pressure switch of FIG. 1. FIG. 3 is a cross-sectional view for explaining the structure of a pressure receiving portion of the pressure switch of the first embodiment. FIG. 4 is a diagram showing an example of how to use the pressure switch. FIG. 5 is a cross-sectional view of a pressure switch according to a second embodiment. FIG. 6 is a cross-sectional view for explaining the operating state of the pressure switch of FIG. 5. FIG. 7 is a cross-sectional view of a pressure switch according to a third embodiment. FIG. 8 is a cross-sectional view for explaining the operating state of the pressure switch of FIG. 7. FIG. 9 is a cross-sectional view showing an exploded portion of the pressure switch of FIG. 7. FIG. 10 is an enlarged view of the portion indicated by arrow X10 in FIG. 7.

[0011] In the present invention, the pressing member that transmits the displacement of the pressure receiving part is divided into a pressing member that is attached to the movable part of the contact mechanism and causes tilting, and a pressing member that is in contact with the pressure receiving part and is fitted into the guide part so that movement is limited to the axial direction, and by connecting these so that they can be tilted, a small pressure switch has been realized that can achieve both positioning of the plunger and reliable movement.

[0012] 1 is a cross-sectional view of one embodiment of a pressure switch 1, and in this pressure switch 1, an airtight pressure-resistant container 31 is formed by a header 2 that holds a contact mechanism 40 and a metal container 3 that is provided with a pressure-receiving portion. That is, the pressure-resistant container 31 includes the header 2 and the container 3. In addition, the contact mechanism 40 includes a fixed contact plate 7, a fixed contact 7A, a movable plate 8, and a movable contact 9.

[0013] The header 2 has two through holes 4A formed in a metal plate 4, and a metal conductive terminal 5 is fixed in each through hole in an airtight manner by an insulating filler 6 having electrical insulation properties such as glass.

[0014] A fixed contact plate 7 is conductively fixed to the tip of one of the conductive terminals. In this embodiment, the fixed contact plate 7 is made of a clad material, such as a copper alloy, with a fixed contact 7A made of a low-resistance metal such as silver or a silver alloy at the tip, thereby reducing the thickness of the switch mechanism. The fixed contact 7A may be a separate component from the fixed contact plate 7, such as a rivet contact made of a low-resistance metal. A conductive leaf spring-shaped movable plate 8 is provided at the tip of the other conductive terminal, and a movable contact 9 is conductively fixed to the tip of the movable plate 8. The movable contact 9 is positioned opposite the contact 7A of the fixed contact plate so as to be able to open and close, and is constantly biased by the movable plate 8 in a direction pressing against the fixed contact.

[0015] The container 3 attached to the header 2 has a pressure-resistant, cylindrical metal housing 10 and a pressure-receiving portion (described later). A first opening 101 at the top of the housing 10 is provided with a flange 10A that extends radially outward, while a second opening 102 is provided with a flange-shaped bottom 10B that extends radially inward, and a guide plate 12 with a through-hole at its center is airtightly fixed to the bottom 10B. The thickness of the guide plate 12 is greater than that of the housing 10 and is thick enough to prevent deformation of the pressure-receiving portion due to excessive pressure.

[0016] A plunger 11 is inserted into the through hole 12A of the guide plate 12 to transmit the displacement of the diaphragm 13 (described below) to the contact mechanism. This plunger 11 is composed of a first pressing member 11A and a second pressing member 11B. The first pressing member 11A has a notch 11C at one end thereof, which is press-fitted into the movable plate 8 of the contact mechanism and fixed thereto. The second pressing member 11B is axially movably held in the through hole 12A of the guide plate 12, and one end is positioned so as to contact the central portion of the diaphragm (described below). Either or both of the first pressing member 11A and the second pressing member 11B are made of an electrically insulating material. In this embodiment, the first pressing member 11A is made of an electrically insulating material such as a ceramic material such as alumina, thereby electrically insulating the metal container 3 and the contact mechanism. The second pressing member 11B may also be made of an electrically insulating material. Furthermore, if the application does not require electrical insulation between the container 3 and the contact mechanism, both the first pressing member 11A and the second pressing member 11B may be made of metal.

[0017] The contact portion between the first pressing member 11A and the second pressing member 11B is not fixed, but abuts against each other in a manner that allows tilting of the first pressing member 11A. That is, the first pressing member 11A and the second pressing member 11B are in contact with each other and can move in a tilting direction relative to the other. The first pressing member 11A is fixed to the movable plate 8, but because the movable plate has a cantilever structure, the angle of the central axis changes with the opening and closing movement. Therefore, if the plunger were integrated, its tilt could interfere with the through hole 12A of the guide plate 12, hindering its movement and preventing the specified performance from being achieved. Therefore, the present disclosure divides the plunger 11 into the first pressing member 11A and the second pressing member 11B, so that even if the first pressing member 11A tilts with the movement of the movable plate 8, the second pressing member 11B can move along the axial direction of the through hole without tilting. Note that the first pressing member 11A and the second pressing member 11B being separated means that the first pressing member 11A and the second pressing member 11B are not physically fixed to each other, that is, they are configured to be separable. The contact portion between the first pressing member 11A and the second pressing member 11B has one end face that is flat and the other end face that is spherical or has a protrusion of a predetermined height in the center. This ensures that even when the first pressing member 11A tilts in accordance with the operation of the movable plate 8, it abuts near the center of the second pressing member 11B, preventing tilt due to an imbalance in the force between the plungers.

[0018] A metal diaphragm 13, which serves as the pressure-receiving portion, is attached to the outer surface of the guide plate 12, and in this embodiment, the peripheral edges of the diaphragm 13 are airtightly fixed by laser welding together with a hold plate 14 provided on the outer side of the diaphragm 13. The diaphragm 13 is formed in a shallow dish shape that bulges outward from the container, and the hold plate 14 is ring-shaped to press only the peripheral edge so as not to interfere with the movement of the diaphragm 13. In addition, a recess 12B is provided around the center of the outer surface of the container of the guide plate 12 so as not to interfere with the inverting movement of the diaphragm 13.

[0019] In this embodiment, a protective plate 15 is disposed on the outside of the hold plate 14 to cover the opening and protect the diaphragm 13. The protective plate 15 has one or more through holes drilled therein, so that it does not obstruct the flow of gas to the pressure-receiving part, but prevents an operator from directly touching the diaphragm during handling.

[0020] The recess 12B is shaped so that the diaphragm 13 comes into surface contact with it during inversion, dispersing and reducing the stress on the diaphragm 13 while preventing deformation when subjected to excessive pressure. If the diaphragm 13 were shaped so that it would not come into contact with the recess 12B, the stress on the diaphragm 13 would be concentrated on the peripheral edge, which is the fixed end, when pressure is applied. Similarly, the impact during inversion and return would be largely applied to the peripheral edge, affecting the characteristics and durability of the diaphragm 13. Therefore, by supporting the diaphragm 13 in the recess 12B, stress can be dispersed and reduced so that it does not concentrate in a specific location. Furthermore, in this embodiment, as shown in Figure 3, a space A formed by a groove or recess is provided along the peripheral edge of the recess 12B to prevent the fixed portion of the inverted diaphragm 13 from directly contacting the recess 12B. Space A allows some freedom of movement near the fixed part of the diaphragm, allowing for deflection of the diaphragm, and in addition, the diaphragm 13 is supported in a planar manner by the aforementioned recess 12B, thereby dispersing and reducing the excessive stress applied when the diaphragm 13 is inverted and returned, thereby minimizing the impact on the operating characteristics and durability of the diaphragm.

[0021] As described above, the flange 10A of the container 3 is hermetically fixed to the metal plate 4 of the header 2 by ring projection welding or other methods, thereby forming a sealed pressure-resistant container for the pressure switch 1. An inert gas is sealed inside the pressure-resistant container to prevent oxidation and contamination of the contact mechanism and ensure stable operation over a long period of time. Furthermore, if it is desired to eliminate the effects of pressure changes inside the container due to temperature changes, the inside of the pressure-resistant container may be reduced to a pressure lower than atmospheric pressure or placed in a vacuum.

[0022] In this pressure switch 1, the diaphragm 13 bulges downward as shown in Figure 1 until the external pressure reaches a predetermined operating pressure. Once the operating pressure is reached, the bulging direction reverses with a snap action, as shown in Figure 2. The displacement caused by this action lifts the movable plate 8 via the plunger 11, causing the movable contact 9 to separate from the fixed contact 7A and cut off the current. When the pressure drops to a return pressure lower than the operating pressure, the diaphragm 13 returns to the bulging position shown in Figure 1 with a snap action, and the movable contact 9 re-contacts the fixed contact 7A, restoring the current. Therefore, this switch can be used to shut down controlled equipment when the pressure rises above the operating pressure, or to sound an alarm when the pressure drops from normal pressure to below the return pressure.

[0023] When this pressure switch 1 is installed in the equipment to be subjected to pressure detection, it is installed so that the pressure-receiving part of the pressure switch 1 receives the gas of the part to be detected. For example, as shown in Figure 4, it may be configured so that the tip of the container 3, which serves as the pressure-receiving part of the pressure switch 1, is inserted and fixed into a mounting hole 51A drilled in the equipment 51. In this mounting example, the pressure switch 1 has lead wires 1A connected to each conductive terminal, and a protective cover 1B is provided at the connection portion. In addition, the space between the container 3 and the mounting hole 51A is airtightly sealed with an annular packing 52, and the pressure switch 1 is fixed on top of the cover 1B with a snap ring 53.

[0024] However, the mounting method is not limited to this, and the pressure switch may be configured so that gas is guided only to the end face of the pressure switch via a pressure tube or the like, or the entire pressure switch may be placed inside a metal airtight pressure-resistant container.

[0025] Furthermore, although the container 3 is made of metal, the switch mechanism can be electrically disconnected from the housing 10, so that the container 3 can be used in devices with a so-called body earth structure without using any special insulating means to hold the container 3.

[0026] By dividing the plunger 11 into the first pressing member 11A and the second pressing member 11B, it is possible to virtually integrate the portion where tilting is possible and the portion where tilting is not permitted. Furthermore, by fixing one pressing member to the contact mechanism side and disposing the other on the container side during assembly, the first and second pressing members are positioned so that they abut at the appropriate positions simply by overlapping them when fixing the header and container. This eliminates the difficult task of inserting the plunger into a predetermined position inside the container that is not visible to the naked eye—in this embodiment, into the through-hole 12A of the guide plate 12—during the fixing process, making manufacturing easier.

[0027] Second Embodiment Next, a pressure switch 21 according to a second embodiment will be described with reference to Figures 5 and 6. The pressure switch 21 shown in Figures 5 and 6 is an example in which the operating conditions are reversed from those of the contact mechanism 40 of the pressure switch 1 of the first embodiment, and is similar to the first embodiment except for the parts described below. The pressure switch 21 includes a contact mechanism 40A instead of the contact mechanism 40 of the first embodiment. The contact mechanism 40A includes a fixed contact plate 27, a fixed contact 27A, a movable plate 28, and a movable contact 29.

[0028] In the first embodiment, the fixed contact 7A is located on the upper side of the fixed contact plate 7 in the drawing, i.e., on the conductive terminal 5 side. In contrast, in the second embodiment, the fixed contact 27A is located on the lower side of the fixed contact plate 27 in the drawing, i.e., on the diaphragm 13 side. The movable contact 29 located at the tip of the movable plate 28 faces the fixed contact 27A facing upward in the drawing. Therefore, when the pressure is below the operating pressure of the pressure switch 21, the movable contact 29 is located away from the fixed contact 27A, leaving the contacts open. When the pressure exceeds the operating pressure, the diaphragm 13 reverses, causing the plunger 11 to move upward, driving the movable plate 28 and bringing the movable contact 29 into contact with the fixed contact 27A, closing the contacts and allowing current to flow. This embodiment can be used to activate a protective device or sound an alarm when pressure rises.

[0029] 7 to 10, a pressure switch 30 according to a third embodiment will be described. In the following description, the same components as those in the first and second embodiments will be denoted by the same reference numerals, and the description thereof will be omitted.

[0030] The pressure switch 30 of the third embodiment differs from the pressure switch 1 of the first embodiment in the specific shapes of the metal plate 4 that constitutes the header 2, the guide plate 12, the hold plate 14, and the protective plate 15, but the other parts are common.

[0031] The pressure switch 30 includes a pressure-resistant vessel 31A, a conductive terminal 5, a contact mechanism 40, a diaphragm 13, a plunger 11, a guide plate 61, and a hold plate 62. The pressure-resistant vessel 31A of the third embodiment includes a header 2A and a vessel 3. The header 2A of the third embodiment includes a metal plate 401 having a through hole 4A and an insulating filler 6. The conductive terminal 5 passes through the through hole 4A. The insulating filler 6 fills the gap between the conductive terminal 5 and the through hole 4A in an airtight and electrically insulating state. That is, the conductive terminal 5 is provided by penetrating the metal plate 401 constituting the pressure-resistant vessel 31A and is fixed to the header 2A in an airtight and electrically insulating state relative to the pressure-resistant vessel 31A.

[0032] The metal plate 401 of the third embodiment has a different specific shape from the metal plate 4 of the first embodiment. The metal plate 401 of the third embodiment is thicker than the metal plate 4 of the first embodiment. Furthermore, the metal plate 401 of the third embodiment has a thick stepped portion 402 on the outer periphery of the metal plate 401. In other words, the metal plate 401 is formed in a so-called stepped shape. The outer diameter of the metal plate 401 on the side opposite to the container 3 is set smaller than the outer diameter on the container 3 side.

[0033] As in the first embodiment, the contact mechanism 40 is provided inside the pressure-resistant vessel 31A and includes a fixed contact plate 7, a fixed contact 7A, a movable plate 8, and a movable contact 9. The fixed contact plate 7 and the movable plate 8 are connected to conductive terminals 5, respectively.

[0034] The container 3 has a metal housing 10. Similar to the first embodiment, the housing 10 has a first opening 101 and a second opening 102. The first opening 101 is located at the upper side of the paper in Fig. 7 and is closed by a header 2A. The second opening 102 is located at the lower side of the paper in Fig. 7 and is provided with a diaphragm 13 via a guide plate 61.

[0035] The guide plate 61 of the third embodiment has a different specific shape from the guide plate 12 of the first embodiment. The guide plate 61 of the third embodiment has an insertion portion 611. The insertion portion 611 is a portion that is inserted into the second opening 102 of the housing 10. The insertion portion 611 protrudes toward the housing 10 relative to the guide plate 61 and is formed in a so-called stepped shape. The outer diameter D1 of the insertion portion 611 is slightly smaller than the inner diameter D2 of the second opening 102. By fitting the insertion portion 611 into the second opening 102, it is possible to easily align the guide plate 61 with the housing 10 during manufacturing of the pressure switch 30.

[0036] As in the first embodiment, the diaphragm 13 is sandwiched and held between a guide plate 61 and a hold plate 62. As in the above embodiments, the guide plate 61 and the hold plate 62 are airtightly fixed by laser welding the periphery of the guide plate 61 and the hold plate 62 with the diaphragm 13 sandwiched between them. The hold plate 62 has an integral protective portion 621. The protective portion 621 performs the same function as the protective plate 15 of the first embodiment. The protective portion 621 covers the side of the diaphragm 13 opposite the housing 10 and has a through-hole 622 that penetrates the protective portion 621. As a result, as with the protective plate 15 of the first embodiment, the protective portion 621 does not obstruct the flow of gas toward the diaphragm 13, which is the pressure-receiving portion, and can prevent an operator from directly touching the diaphragm 13 during handling.

[0037] The pressure switch 30 of the third embodiment also provides the same effects as the pressure switch 1 of the first embodiment described above.

[0038] That is, the pressure switch 30 of the third embodiment includes a metal pressure-resistant vessel 31A, a conductive terminal 5, a contact mechanism 40, a diaphragm 13, and a plunger 11 serving as a pressing member. The conductive terminal 5 penetrates the pressure-resistant vessel 31A and is fixed to the pressure-resistant vessel 31A in an airtight and insulated state. The contact mechanism 40 is electrically connected to the conductive terminal 5 and is provided inside the pressure-resistant vessel 31A. The diaphragm 13 is airtightly attached to the pressure-resistant vessel 31A, covering the second opening 102 of the pressure-resistant vessel 31A, and is operable at or above a predetermined operating pressure and returnable at a return pressure lower than the operating pressure. The plunger 11 functions as a pressing member and transmits displacement due to the operation and return of the diaphragm 13 to open and close the contact mechanism 40.

[0039] The plunger 11, which is a pressing member, includes a first pressing member 11A fixed to the contact mechanism 40 side and a second pressing member 11B in contact with the diaphragm 13, and the first pressing member 11A and the second pressing member 11B are in contact with each other so that at least one of them can move in a direction inclined relative to the other. The plunger 11 receives the displacement of the diaphragm 13 with the second pressing member 11B and transmits it to the contact mechanism 40 via the first pressing member 11A, thereby pressing the contact mechanism 40, thereby opening and closing the contact mechanism 40.

[0040] In this way, in the pressure switch 30 of the third embodiment, as in the above embodiments, the plunger 11 that transmits the displacement of the diaphragm 13, which is the pressure receiving portion, to the contact mechanism 40 is divided into the first pressing member 11A and the second pressing member 11B, thereby absorbing the tilt that occurs during operation. Furthermore, by dividing the plunger 11 into the first pressing member 11A and the second pressing member 11B, a structure is achieved in which the tilt of the second pressing member 11B, which is the other component, is not affected by the portion where tilt is not acceptable, for example, the first pressing member 11A fixed to the movable plate 8, thereby suppressing the occurrence of operational resistance between components that becomes a problem when the device is made smaller.

[0041] The pressure switch 30 further includes a guide plate 61. The guide plate 61 restricts the amount of displacement of the diaphragm 13 to the side that bulges when the diaphragm 13 is inverted. The guide plate 61 also has a recess 12B that causes the diaphragm 13 to come into contact with the guide plate 61 when the diaphragm 13 is inverted, thereby restricting the stress applied to the diaphragm 13.

[0042] As a result, the reversal movement of the diaphragm 13 is received by the recessed portion 12B, so that stress can be dispersed and reduced without being concentrated in a specific location. Also, as shown in Figure 10, the pressure switch 30 of the third embodiment also has a space A, similar to the above-described embodiments. Here, the diaphragm 13 has a dish-shaped portion 131 that bulges out like a dish, and a clamping portion 132 that is sandwiched between the guide plate 61 and the hold plate 62, similar to the first embodiment.

[0043] Furthermore, the dish-shaped portion 131 may be formed by drawing. Due to manufacturing reasons, a bulging portion 133 is formed at the boundary between the dish-shaped portion 131 and the clamping portion 132. The bulging portion 133 is a portion that bulges slightly in the direction opposite to the bulging direction of the dish-shaped portion 131. If the guide plate 61 presses the bulging portion 133 while the diaphragm 13 is clamped between the guide plate 61 and the hold plate 62, the amount of displacement when the diaphragm 13 returns from the inverted state will be small, and there is a risk that the operating pressure during the return will differ from what was expected.

[0044] In contrast, the pressure switch 30 is provided with the space A, which prevents the bulge 133 from being pressed by the guide plate 61. This reduces the change in characteristics when the diaphragm 13 reverses.

[0045] Furthermore, the contact portions between the first pressing member 11A and the second pressing member 11B are either flat on one side and spherical on the other side, or have a protrusion of a predetermined height at the center of the other. In the third embodiment, as in the above embodiments, the first pressing member 11A has a flat surface C1 at the contact portion with the second pressing member 11B. The second pressing member 11B has a protrusion C2 at the contact portion with the first pressing member 11A. The protrusion C2 is provided on the surface of the second pressing member 11B facing the first pressing member 11A at the radial center of the second pressing member 11B and protrudes toward the first pressing member 11A. The protrusion C2 may be configured as a spherical surface. Alternatively, the first pressing member 11A may have the protrusion C2, and the second pressing member 11B may have the flat surface C1.

[0046] With this, the movable plate 8 is elastically deformed by the reversal movement of the diaphragm 13, and even if the first pressing member 11A is tilted relative to the second pressing member 11B, the protrusion C2 comes into contact with the vicinity of the center of the flat surface C1. This prevents poor contact between the first pressing member 11A and the second pressing member 11B, which is caused by tilt due to an imbalance in the force between the first pressing member 11A and the second pressing member 11B, and makes it possible to maintain good contact even if the first pressing member 11A and the second pressing member 11B are tilted relative to each other.

[0047] The configuration of the third embodiment may be appropriately incorporated into the pressure switch 21 of the second embodiment.

[0048] As described above, the pressure switches 1, 21, and 30 described in each embodiment can reliably operate in response to pressure changes and can increase the durability of the diaphragm, and can be used to control equipment and issue alarms in response to pressure abnormalities in the target equipment.

[0049] The above-described embodiments are presented as examples and are not intended to limit the scope of the invention. The above-described embodiments can be implemented in combination with each other in part or in whole. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The present embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

Claims

1. A pressure switch comprising: a metallic pressure vessel; a conductive terminal which penetrates the pressure vessel and is fixed to the pressure vessel in an airtight and insulated state; a contact mechanism which is electrically connected to the conductive terminal and is provided inside the pressure vessel; a diaphragm which covers an opening of the pressure vessel and is attached to the pressure vessel in an airtight state, the diaphragm operating at or above a predetermined operating pressure and capable of returning to its original position at a return pressure lower than the operating pressure; and a pressing member which transmits displacement due to the operation and return of the diaphragm to open and close the contact mechanism, the pressing member including a first pressing member fixed to the contact mechanism side and a second pressing member in contact with the diaphragm, the first pressing member and the second pressing member being in contact with each other so as to be movable in an inclined direction, and the pressing member receives displacement of the diaphragm at the second pressing member and transmits it to the contact mechanism via the first pressing member to press the contact mechanism, thereby opening and closing the contact mechanism.

2. The pressure switch as claimed in claim 1, further comprising a guide plate which restricts the amount of displacement of the diaphragm on the side which bulges during inversion of the diaphragm, the guide plate having a recess which limits the stress applied to the diaphragm when the diaphragm comes into contact with the guide plate during inversion of the diaphragm.

3. The pressure switch according to claim 2, wherein the guide plate further has a space around the periphery of the recess near the fixing portion of the diaphragm.

4. The pressure switch as set forth in claim 1, wherein the contact portion between the first pressing member and the second pressing member is a flat surface on one side and a spherical surface on the other side, or a protrusion provided in the center and protruding to the one side.

5. The pressure switch according to claim 1, wherein either or both of the first pressing member and the second pressing member are made of an electrically insulating material.

6. The pressure switch according to any one of claims 1 to 5, wherein the inside of the pressure-resistant container is at a reduced pressure below atmospheric pressure or at a vacuum.

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