pressure switch

Abstract

This invention provides a pressure switch that can set the reversal pressure required for the reversal operation of a diaphragm with high precision. [Solution] The pressure switch 1 is characterized by comprising a diaphragm 131c, an operating shaft 132, a switch unit 12 in which a plurality of contacts 123 including a movable contact 123b that can move by receiving the force from the reversal movement of the diaphragm 131c as a driving force, a biasing part 14 provided separately from the operating shaft 132 and capable of directly biasing the diaphragm 131c, and a reversal pressure adjustment part 15 that adjusts the reversal pressure required for the reversal movement of the diaphragm 131c by adjusting the biasing force by the biasing part 14.

Description

[Technical Field]

[0001] The present invention relates to a pressure switch that moves a contact in response to pressure fluctuation. [Background Art]

[0002] Conventionally, pressure switches that move contacts by moving an operating shaft in response to pressure fluctuation have been used (see, for example, Patent Document 1). In this pressure switch, a diaphragm performs a reversing operation upon receiving pressure fluctuation, and the contact is moved by moving a predetermined mechanism section via the operating shaft that receives the reversing operation of the diaphragm. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2024-117302 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] Here, in the above-described pressure switch, the reversing pressure required for the reversing operation of the diaphragm may vary due to various factors, such as dimensional errors of related components, variations in properties of the material itself such as elastic modulus, manufacturing errors of the diaphragm itself, manufacturing errors when assembling the diaphragm, and deformation of the holding structure of the diaphragm.

[0005] Accordingly, an object of the present invention is to focus on the above-described problems, and provide a pressure switch that can set the reversing pressure required for the reversing operation of the diaphragm with high accuracy. [Means for Solving the Problem]

[0006] To solve the above problems, the pressure switch is characterized by comprising: a diaphragm that constitutes a part of a partition wall that divides a pressure space and performs a reversal operation between a first state that is convex inward and a second state that is convex outward in response to a pressure change in the pressure space; an operating shaft that is arranged on the outside of the space of the diaphragm so as to extend in a direction intersecting the diaphragm and moves in accordance with the reversal operation of the diaphragm; a switch unit in which a plurality of contacts, including a movable contact that is movable by receiving as a driving force from the operating shaft the force in the direction of the reversal operation generated on the operating shaft by the reversal operation of the diaphragm; a biasing part provided separately from the operating shaft and capable of directly biasing the diaphragm in the direction of the operation; and a reversal pressure adjusting part that adjusts the reversal pressure required for the reversal operation of the diaphragm by adjusting the biasing force by the biasing part.

[0007] With the above-described pressure switch, even if there is variation in the diaphragm's reversal pressure, this variation can be suppressed by adjusting the reversal pressure adjustment unit. In other words, with the above-described pressure switch, the reversal pressure required for the diaphragm's reversal operation can be set with high precision.

[0008] Here, it is preferable that the biasing unit is provided in a compressed state in the operating direction and has a compression spring that generates the biasing force on the diaphragm, and that the reversal pressure adjustment unit adjusts the biasing force by adjusting the amount of compression of the compression spring in the operating direction.

[0009] With this configuration, the diaphragm's reversal pressure can be effectively adjusted by adjusting the amount of compression of the compression spring.

[0010] Furthermore, it is preferable that the reversal pressure adjustment unit is a screw member having a male thread that screws into a female thread provided on a predetermined member, and that the biasing force by the biasing unit is adjusted by changing the amount of screwing into the female thread.

[0011] With this configuration, the biasing force can be adjusted, in other words, the amount of compression of the compression spring, by simply changing the amount the male screw is threaded.

[0012] Furthermore, the reversal pressure adjustment section is preferably a member that presses the switch-side spring end of the compression spring on the opposite side of the diaphragm in the direction of operation, and through which the operating shaft is relatively movable in the direction of operation, thereby adjusting the amount of compression of the compression spring by increasing or decreasing the relative distance between the diaphragm-side spring end and the switch-side spring end of the compression spring.

[0013] With this configuration, the amount of compression of the compression spring can be effectively adjusted by pressing the switch-side spring end with the reversal pressure adjustment section, without affecting the operating shaft.

[0014] Furthermore, the switch unit further comprises an intermediate block positioned between the housing and the diaphragm, wherein the intermediate block is provided with a through hole that penetrates in the operating direction so as to allow the operating shaft to pass through to the inside, and has a female thread cut into its inner circumferential surface, and the reversal pressure adjustment section has a male thread cut into its outer circumferential surface around a central axis along the operating direction to screw into the female thread, and it is preferable to adjust the amount of compression of the compression spring by increasing or decreasing the relative distance between the diaphragm-side spring end and the switch-side spring end by changing the amount of screwing into the through hole.

[0015] With this configuration, the position of the reversal pressure adjustment part is stabilized by screwing it into the through hole of the intermediate block, and the amount of compression of the compression spring can be precisely adjusted by changing the amount of screwing.

[0016] Furthermore, it is preferable that the through hole in the intermediate block is a hole with a diameter that allows both the operating shaft and the compression spring to pass through, and that the reversal pressure adjustment unit presses the switch-side spring end of the compression spring, which is at least partially housed inside the through hole.

[0017] With this configuration, the compression spring receives pressure from the switch-side spring end while at least a portion of it is housed in the through hole of the intermediate block. This stabilizes the position of the compression spring, allowing for more precise adjustment of the compression amount.

[0018] Furthermore, the biasing portion is configured to further include a contact biasing piece that is sandwiched between the operating shaft and the diaphragm and is in contact with the diaphragm, and is biased by the compression spring, wherein the contact biasing piece directly biases the diaphragm with the biasing force from the compression spring and transmits the force in the direction of operation due to the reversal movement of the diaphragm to the operating shaft.

[0019] With this configuration, by providing a contact biasing piece in the biasing section that is biased by a compression spring while in contact with the diaphragm, it becomes possible to set the contact area with the diaphragm independently of the size of the compression spring. As a result, the diaphragm can be biased while minimizing the impact on the reversing operation by reducing the contact area with the diaphragm.

[0020] Furthermore, the contact biasing piece has a support portion that contacts and supports the diaphragm-side spring end of the compression spring that is on the diaphragm side and the diaphragm-side shaft end of the operating shaft that is on the diaphragm side, and a projection that protrudes from the support portion and contacts the diaphragm, wherein the support portion is a portion that extends with a width capable of supporting the entire diaphragm-side spring end, and the projection is preferably a rod-shaped projection whose cross-sectional area in the direction intersecting the direction of operation is smaller than the cross-sectional area of ​​the support portion in the direction intersecting the direction of operation.

[0021] According to this configuration, by supporting the diaphragm-side spring end and the diaphragm-side shaft end with a sufficiently wide support portion, it is possible to stabilize the transmission of force from the diaphragm to the operating shaft and the reception of the biasing force from the compression spring. Further, by making the cross-sectional area of the protrusion abutting on the diaphragm smaller than the cross-sectional area of the support portion, the influence on the reversing operation of the diaphragm can be more effectively suppressed.

[0022] Further, it is preferable that the biasing portion is the compression spring itself, and the diaphragm is directly biased by bringing the diaphragm-side spring end, which is on the diaphragm side of the compression spring, into contact with the diaphragm.

[0023] According to this configuration, the diaphragm can be biased with a reduced number of components.

[0024] The apparatus further comprises: a space-side block that defines the pressure space between the space-side block and the diaphragm; a stopper block disposed on the switch unit side as viewed from the diaphragm, that sandwiches the diaphragm between the stopper block and the space-side block, and suppresses displacement of the diaphragm to a predetermined amount when the diaphragm is in the second state; and a connecting portion that connects the space-side block, the diaphragm, and the stopper block to the switch unit, wherein the stopper block is provided with a passage hole that penetrates the stopper block in the operation direction so as to allow the operating shaft to pass inside, and the internal thread is cut on an inner circumferential surface of the passage hole, and it is preferable that the reversal pressure adjusting portion has the external thread that is screwed into the internal thread cut on an outer circumferential surface around a central axis along the operation direction, and adjusts the compression amount of the compression spring by increasing or decreasing the relative distance between the diaphragm-side spring end and the switch-side spring end by changing the screwing amount into the passage hole.

[0025] According to this configuration, while effectively utilizing the holding structure of the diaphragm, the compression amount of the compression spring can be adjusted by changing the screwing amount of the reversal pressure adjusting portion into the passage hole in the stopper block.

[0026] Furthermore, it is preferable that the through hole in the stopper block is a hole with a diameter that allows both the operating shaft and the compression spring to pass through, and that the reversal pressure adjustment unit presses the switch-side spring end of the compression spring, which is at least partially housed inside the through hole.

[0027] With this configuration, the compression spring receives pressure from the switch-side spring end while at least a portion of it is housed in the through hole of the stopper block. This stabilizes the position of the compression spring, allowing for more precise adjustment of the compression amount.

[0028] Furthermore, the diaphragm is in one of the first and second states when no pressure is applied to it, and reverses to the other state in response to the pressure change. Preferably, the spring constant of the biasing part is smaller than the spring constant of the diaphragm from the no-pressure state until the reversal operation occurs.

[0029] With this configuration, the spring constant of the biasing section is smaller than the spring constant of the diaphragm from the unpressurized state until the reversal movement occurs. Therefore, compared to using a strong biasing section with a large spring constant, it is possible to miniaturize the surrounding structure and reduce costs. Furthermore, by using a weak biasing section with a small spring constant as described above, it is possible to adjust the biasing force with higher precision in the reversal pressure adjustment section compared to using a strong biasing section with a large spring constant. [Effects of the Invention]

[0030] The pressure switch described above allows for highly accurate setting of the reversal pressure required for the diaphragm's reversal operation. [Brief explanation of the drawing]

[0031] [Figure 1] This is a cross-sectional view showing a pressure switch according to the first embodiment. [Figure 2] This is a cross-sectional view showing a pressure switch according to a second embodiment. [Figure 3] This is a cross-sectional view showing a pressure switch according to a third embodiment. [Modes for carrying out the invention]

[0032] The following describes one embodiment of a pressure switch. First, the first embodiment will be described.

[0033] Figure 1 is a cross-sectional view showing a pressure switch according to the first embodiment.

[0034] In this embodiment, the pressure switch 1 is a normally closed type switch in which the conductive state of a pair of metal terminals 121 is ON before the operation of the operating shaft 132, and transitions to the OFF state after the operation of the operating shaft 132. Figure 1 shows the pressure switch 1 in the ON state. This pressure switch 1 first comprises a coupling 11, a switch unit 12, and a drive unit 13.

[0035] The joint 11 is the part to which a pipe through which pressurized fluid flows is connected, and which introduces that pressurized fluid into the pressure space 13a in the drive unit 13.

[0036] The switch unit 12 is a unit in which a pair of contacts 123 are housed in a covered cylindrical housing 122 so as to be able to move in and out of contact in accordance with the driving force from the drive unit 13. In this switch unit 12, the conductive state of a pair of metal terminals 121 is switched between an on state and an off state by the moving of the pair of contacts 123.

[0037] The drive unit 13 is positioned on the opening 122b side of the housing 122 of the switch unit 12 and is a unit that applies a driving force to the switch unit 12 for the separation of the contacts. This driving force is obtained by a diaphragm unit 131 provided in the drive unit 13 and is applied to the switch unit 12 via an operating shaft 132. In the diaphragm unit 131, a diaphragm 131c is provided so as to constitute part of the partition wall that divides the pressure space 13a. The diaphragm 131c is provided so as to be reversible between a first state where it is convex inward and a second state where it is convex outward depending on the pressure change in the pressure space 13a. The operating shaft 132 is positioned on the outside of the space of the diaphragm 131c and extends in a direction intersecting the diaphragm 131c. The operating shaft 132 applies the driving force to the switch unit 12 by moving in response to the reversal operation of the diaphragm 131c.

[0038] The switch unit 12 and drive unit 13, which were briefly described above, will now be explained in more detail. First, the drive unit 13 will be described.

[0039] The drive unit 13 includes a diaphragm unit 131, an operating shaft 132, a shaft guide 133, a stopper retainer 134, a switch-side O-ring 135, a diaphragm-side O-ring 136, and a connecting frame 137.

[0040] The diaphragm unit 131 is formed by sandwiching a disc-shaped diaphragm 131c between a cap 131a, which is a circular dish shape with a joint 11 in the center, and a disc-shaped stopper 131b, and then joining them at a connecting portion 131d on the outer circumference. The connecting portion 131d is formed by welding. In this embodiment, the diaphragm 131c is a laminated plate made up of multiple disc members stacked on top of each other. However, the diaphragm provided in the pressure switch is not limited to a laminated plate diaphragm 131c as in this embodiment, but may be a single plate. Also, the joint 11 and the cap 131a are each formed from separate materials and connected by brazing or the like, but are not limited to this, and the joint 11 and the cap 131a may be formed integrally by, for example, machining.

[0041] In this diaphragm unit 131, the space partitioned by the cap 131a and the diaphragm 131c forms a pressure space 13a, into which pressurized fluid is introduced via the joint 11. The diaphragm 131c reverses direction in response to pressure fluctuations of the pressurized fluid in this pressure space 13a. In this embodiment, at low pressures below a predetermined threshold, the diaphragm 131c is in a concave shape recessed towards the cap 131a (the first state described above), and at high pressures exceeding the threshold, it reverses to a convex shape bulging towards the stopper 131b (the second state described above). The diaphragm unit 131 is arranged such that the direction of operation D11 of the reversal movement of the internal diaphragm 131c is aligned with the central axis X1 of the pressure switch 1. The stopper 131b plays a role in limiting the displacement of the diaphragm 131c during reversal to a predetermined amount. In this stopper 131b, a stopper through-hole 131b-1 is provided in the center through which the central axis X1 passes, allowing a component for biasing the diaphragm 131c, described later, to pass through together with the operating shaft 132.

[0042] The operating shaft 132 is positioned outside the space of the diaphragm 131c, extending in a direction intersecting the diaphragm 131c, and is a movable member along the central axis X1, i.e., in the operating direction D11 of the diaphragm 131c. One end of the operating shaft 132 faces the diaphragm 131c side, and the other end faces the contact plate 124 side of the switch unit 12. When the diaphragm 131c is in the first state, the operating shaft 132 is in a state where it can move with a slight stroke in the operating direction D11 between the contact plate 124 and the contact biasing piece 142 described later. When the diaphragm 131c reverses to the second state, the reversal pushes it up in the pushing direction D111, pushing up the contact plate 124.

[0043] In this embodiment, the diaphragm 131c is a component that can take on a first convex state toward the inside of the space without being subjected to a biasing force toward the inside of the space when the pressure difference between the inside and outside of the pressure space 13a is approximately zero and no pressure is applied to the diaphragm 131c in an unpressurized state. However, the diaphragm is not limited to this, and in an unpressurized state, the diaphragm alone may be in a flat state and may take on a first convex state toward the inside of the space due to a biasing force from another component, such as the contact plate 124 mentioned above.

[0044] The shaft guide 133 is an annular member positioned to close the opening 122b of the housing 122 of the switch unit 12, and has a cylindrical guide hole 133a in the center that penetrates along the operating direction D11 of the diaphragm 131c. The stopper retainer 134 is an annular intermediate block positioned between the housing 122 of the switch unit 12 and the diaphragm unit 131. In the center of the stopper retainer 134, there is a through hole 134a that penetrates in the operating direction D11 so that a component for biasing the diaphragm 131c, described later, passes through to the inside along with the operating shaft 132. Furthermore, this stopper retainer 134 is positioned to be pressed against the stopper 131b of the diaphragm unit 131, and plays a role in suppressing the displacement of the stopper 131b when the diaphragm 131c reverses to its second state. The shaft guide 133 and the stopper retainer 134 are positioned so that the guide hole 133a of the shaft guide 133 and the through hole 134a of the stopper retainer 134 are in communication with each other and overlap. The operating shaft 132 is guided in the operating direction D11 by passing through the guide hole 133a of the shaft guide 133, and operates with one end facing the diaphragm 131c after passing through the through hole 134a of the stopper retainer 134. The switch-side O-ring 135 is an annular sealing member positioned to be sandwiched between the outer circumference of the shaft guide 133 and the inner part of the opening 122b of the housing 122, and the outer circumference of the stopper retainer 134. The switch-side O-ring 135 seals the space between the shaft guide 133 and the opening 122b of the housing 122 and the stopper retainer 134. Furthermore, a cylindrical crimping plate 134b is provided on the outer peripheral edge of the stopper retainer 134 on the switch side, which accommodates the opening 122b side of the housing 122. The stopper retainer 134 is crimped to the switch unit 12 by the crimping plate 134b while sealed by the switch-side O-ring 135. The stopper retainer 134 is also positioned to overlap the stopper 131b of the diaphragm unit 131. The diaphragm-side O-ring 136 is an annular sealing member that is sandwiched between the stopper retainer 134 and the stopper 131b of the diaphragm unit 131, and is positioned to surround the through hole 134a and the stopper through hole 131b-1.This diaphragm-side O-ring 136 seals the space between the stopper retainer 134 and the diaphragm unit 131.

[0045] The connecting frame 137 is a cylindrical frame member that crimps the diaphragm unit 131 to the stopper retainer 134 in the sealed state described above. The connecting frame 137 has a thick-walled cylindrical main frame 137a that houses the diaphragm unit 131 on its inside, and a thin-walled cylindrical crimping plate 137b that houses the diaphragm side of the stopper retainer 134 on its inside. The crimping connection of the diaphragm unit 131 to the stopper retainer 134 is performed by this thin-walled cylindrical crimping plate 137b.

[0046] Next, we will explain the details of the switch unit 12.

[0047] The switch unit 12 comprises a pair of metal terminals 121, a housing 122, a pair of contacts 123, and a contact plate 124.

[0048] The pair of metal terminals 121 comprises a first terminal 121a and a second terminal 121b. The first terminal 121a is a terminal piece formed by bending one end of a metal strip extending along the operating direction D11 toward the inside of the housing 122 in an L-shape. The second terminal 121b is a terminal piece formed by bending one end of a metal strip toward the inside of the housing 122 in an L-shape so as to be positioned opposite the first terminal 121a. The first terminal 121a and the second terminal 121b are fixed to the housing 122 by various fixing methods such as crimping, welding, or adhesive fixing, with the terminal portion protruding from the circular cover portion 122a.

[0049] The housing 122 is a covered cylindrical frame portion around a central axis X1, and a pair of metal terminals 121 are attached to it so that they protrude from the outer circumference, passing through the circular lid portion 122a. The terminal portions of these metal terminals 121 are facing each other. In addition, a pair of contacts 123 and a contact plate 124 are arranged inside the housing 122. The opening 122b side of the housing 122 is crimped to the drive unit 13 via a stopper retainer 134, while housing the shaft guide 133 through which the operating shaft 132 passes.

[0050] The pair of contacts 123 consists of a fixed contact 123a and a movable contact 123b. The fixed contact 123a is a conductive contact member fixed to the first terminal 121a of the pair of metal terminals 121. The fixed contact 123a is crimped to the L-shaped bent portion 121a-1 of the first terminal 121a, with its contact surface with the movable contact 123b facing the circular lid portion 122a of the housing 122. Note that the fixing of the fixed contact 123a is not limited to crimping; various fixing methods such as welding and adhesive bonding with conductive adhesive can be used.

[0051] The movable contact 123b is electrically connected to the second terminal 121b of the pair of metal terminals 121 via a contact plate 124, and is a conductive contact member that can move toward and away from the fixed contact 123a. The movable contact 123b is crimped and fixed to the edge portion of the contact plate 124, similar to the fixed contact 123a, with the contact surface of the movable contact 123b facing the contact surface of the fixed contact 123a. However, the fixing of the movable contact 123b is not limited to crimping, and various fixing methods such as welding and adhesive fixing with conductive adhesive can be used.

[0052] The contact plate 124 is a conductive metal leaf spring that extends from a fixed portion 124a fixed to the second terminal 121b to the contact / separation position with respect to the fixed contact 123a, with the edge portion on the contact / separation side being a movable portion 124b, so as to intersect with the central axis X1. The fixed portion 124a of the contact plate 124 is crimped to the L-shaped bent portion 121b-1 of the second terminal 121b. Note that the fixing of the contact plate 124 is not limited to crimping, and various fixing methods such as welding and adhesive fixing with conductive adhesive can be used. The movable contact 123b is fixed to the movable portion 124b of the contact plate 124. Then, at the load-receiving portion 124c in the middle of the extending direction D12 from the fixed portion 124a to the movable portion 124b, it receives driving force from the switch-side shaft end 132a of the operating shaft 132 of the drive unit 13. The contact plate 124 receives the movement of the operating shaft 132 in the operating direction D11 as a driving force at the load-receiving portion 124c, thereby moving the movable portion 124b and causing the movable contact 123b to move toward and away from the fixed contact 123a.

[0053] In this case, the diaphragm 131c in the drive unit 13 may experience variations in the reversal pressure required for the reversal operation due to various factors. Examples of these variations include dimensional errors in related parts of the pressure switch 1, variations in the properties of the material itself such as the modulus of elasticity, and manufacturing errors of the diaphragm 131c itself. Furthermore, manufacturing errors when assembling the diaphragm 131c into a unit as described above, or deformation of the cap 131a and stopper 131b, which are the holding structures for the diaphragm 131c, can also be cited as examples. In order to suppress variations caused by such factors and enable high-precision setting of the reversal pressure, the pressure switch 1 in this embodiment is provided with a biasing unit 14 and a reversal pressure adjustment unit 15.

[0054] The biasing unit 14 is provided as a separate component from the operating shaft 132 and is capable of directly biasing the diaphragm 131c in the operating direction D11. This configuration means that the biasing unit 14 can bias the diaphragm 131c without going through the operating shaft 132. The reversal pressure adjustment unit 15 is a component that adjusts the reversal pressure required for the reversal operation of the diaphragm 131c by adjusting the biasing force provided by the biasing unit 14.

[0055] In this embodiment, the biasing section 14 is composed of a coil spring 141 and a contact biasing piece 142. The coil spring 141 is a compression spring that has a coil shape surrounding the operating shaft 132 and is provided in a compressed state in the operating direction D11, generating a biasing force on the diaphragm 131c. The contact biasing piece 142 is a member that is sandwiched between the operating shaft 132 and the diaphragm 131c and is biased by the coil spring 141 while in contact with the diaphragm 131c. The contact biasing piece 142 directly biases the diaphragm 131c with the biasing force from the coil spring 141 and transmits the force in the operating direction D11 caused by the reversal movement of the diaphragm 131c to the operating shaft 132. The contact biasing piece 142 is formed having a support portion 142a and a projection portion 142b. The support portion 142a is the part of the coil spring 141 that contacts and supports the diaphragm-side spring end 141a on the diaphragm 131c side and the diaphragm-side shaft end 132b on the operating shaft 132. This support portion 142a extends with a width that can support the entire diaphragm-side spring end 141a, and in this embodiment it is a disc-shaped portion. The projection 142b is the part of the support portion 142a that protrudes from the center of the surface on the diaphragm 131c side and contacts the diaphragm 131c. This projection 142b is a rod-shaped projection whose cross-sectional area in the direction intersecting the operating direction D11 is smaller than the cross-sectional area in the direction intersecting the support portion 142a (i.e., the disc area), and furthermore, it is a rod-shaped projection that is thinner than the spring diameter of the coil spring 141. In this embodiment, the diaphragm 131c is incorporated into the diaphragm unit 131 described above, and a stopper through-hole 131b-1 is provided in the center of the stopper 131b of the diaphragm unit 131. The stopper through-hole 131b-1 is a through-hole that allows the rod-shaped projection 142b to pass through and has a smaller diameter than the spring diameter of the coil spring 141. Examples of this small-diameter through-hole include holes that are slightly larger in diameter than the operating shaft to allow the operating shaft to pass through to the diaphragm, which are provided in many stoppers of conventional diaphragm units. The rod-shaped projection 142b passes through the stopper through-hole 131b-1 and directly contacts the diaphragm 131c.

[0056] The reversal pressure adjustment section 15 adjusts the biasing force on the diaphragm 131c by adjusting the amount of compression of the coil spring 141, which acts as a compression spring in the biasing section 14, in the operating direction D11. This reversal pressure adjustment section 15 is a member that presses the switch-side spring end 141b of the coil spring 141, which is on the opposite side of the diaphragm 131c in the operating direction D11 of the diaphragm 131c. In addition to performing this pressing, the reversal pressure adjustment section 15 is also a member through which the operating shaft 132 is relatively movable in the operating direction D11. In this embodiment, the reversal pressure adjustment section 15 has a cap-shaped cover that fits over the switch-side spring end 141b so that the switch-side spring end 141b is housed inside. A through hole 151a for the operating shaft 132 is provided in the center of the cap ceiling portion 151 of the reversal pressure adjustment section 15. This cap-shaped reverse pressure adjustment section 15 adjusts the amount of compression of the coil spring 141 by increasing or decreasing the relative distance between the diaphragm-side spring end 141a and the switch-side spring end 141b of the coil spring 141.

[0057] Furthermore, the reversal pressure adjustment section 15 is a screw member with a male thread that screws into a female thread provided on a predetermined member of the pressure switch 1. Specifically, the screw member has the following configuration. First, as described above, a through hole 134a is provided in the center of the stopper retainer 134 of the drive unit 13, through which the operating shaft 132, coil spring 141, and contact biasing piece 142 pass inward. A female thread is cut into the inner circumferential surface 134a-1 of this through hole 134a. On the other hand, a male thread that screws into the above-mentioned female thread is cut into the outer circumferential surface 152 of the reversal pressure adjustment section 15. The reversal pressure adjustment section 15 adjusts the amount of compression of the coil spring 141 by increasing or decreasing the relative distance between the diaphragm-side spring end 141a and the switch-side spring end 141b by changing the amount of screwing into the through hole 134a. The cap ceiling portion 151 of the reversal pressure adjustment section 15 has two connecting holes 151b formed therein for connecting a tool when changing the amount of screwing into the through hole 134a.

[0058] Furthermore, the shaft guide 133 in this embodiment is provided with a recess on the side opposite to the stopper retainer 134, and this recess serves as a accommodating space for the reversal pressure adjustment unit 15, which exits the through hole 134a of the stopper retainer 134 towards the shaft guide 133. By providing such an accommodating space in the shaft guide 133, the amount of movement of the reversal pressure adjustment unit 15 can be increased, and the range of adjustment by the reversal pressure adjustment unit 15 can be increased.

[0059] The reversal pressure is adjusted as follows. First, in this embodiment, a diaphragm unit 131 is used which is equipped with a diaphragm 131c that reverses at a pressure lower than the target set reversal pressure. The adjustment to the set reversal pressure is performed on the drive unit 13 when the switch unit 12 and shaft guide 133 are not attached. In this state, the operating shaft 132 is supported by passing through the through hole 151a of the reversal pressure adjustment part 15. In this state, the drive unit 13 is set to unpressurized before the introduction of pressurized fluid from the coupling 11 to the pressure space 13a, and the reversal pressure adjustment part 15 is screwed, for example, to the maximum extent into the through hole 134a of the stopper retainer 134. This screwing sets the biasing force applied to the diaphragm 131c from the biasing part 14 to a size that causes the diaphragm 131c to reverse at a pressure higher than the set reversal pressure. Subsequently, pressurized fluid is introduced from the joint 11 into the pressure space 13a so that the internal pressure of the pressure space 13a becomes the set reversal pressure. In this state, the reversal pressure adjustment unit 15 is loosened until the diaphragm 131c reverses. The loosening of the reversal pressure adjustment unit 15 is stopped when the diaphragm 131c is in the reversed position, and the reversal pressure adjustment unit 15 is fixed to the stopper retainer 134 by adhesive, welding, crimping, etc., in that reversed position, and the adjustment to the set reversal pressure is completed. The set state of the reversal pressure is maintained by fixing the reversal pressure adjustment unit 15 in the reversed position. In this embodiment, after this adjustment is completed, the switch unit 12 and the shaft guide 133 are attached and the pressure switch 1 is assembled.

[0060] Here, the diaphragm 131c, in an unpressurized state where no pressure is applied to the diaphragm 131c, is in one of two states: a first state where it is convex inward of the pressure space 13a, or a second state where it is convex outward (in this embodiment, the first state). Then, in response to a change in pressure in the pressure space 13a, it reverses to the other state (in this embodiment, the second state). At this time, the spring constant of the biasing part 14, which has become a compression spring, is smaller than the spring constant of the diaphragm 131c from the unpressurized state until the reversal operation occurs. This relationship regarding the spring constants is the same for the second and third embodiments described later.

[0061] In this embodiment, a diaphragm 131c for pressure detection is provided as an example of a diaphragm, which enters a first state in an unpressurized state and reverses to a second state in response to a pressure change (pressure change). However, the diaphragm is not limited to this, and any diaphragm that reverses between a first state and a second state in response to a pressure change in the pressure space may be used for negative pressure detection, such as the following. That is, the diaphragm may be the opposite of this embodiment, entering a second state where it is convex outward in the pressure space 13a in an unpressurized state, and then reversing to a first state where it is convex inward in response to a pressure change (negative pressure change) for negative pressure detection.

[0062] Below, specific numerical examples of the spring constants of the biasing unit 14 and the diaphragm 131c, for both the pressurized and negative pressure detection units, are given in Table 1. The numerical examples in Table 1 are also applicable to the second and third embodiments described later.

[0063] [Table 1]

[0064] Table 1 shows numerical examples for the spring constant of the biasing section 14, corresponding to two types of specifications: normal adjustment specification (first biasing section) and fine adjustment specification (second biasing section). First, the spring constant of the normal adjustment specification (first biasing section) is 0.008~0.015 (×103 The spring constant of the fine adjustment specification (second biasing part) is 0.00004 to 0.0001 (×10). Next, regarding the spring constant of the fine adjustment specification (second biasing part), the smaller the value, the finer the reversal pressure required for the reversal operation of the diaphragm 131c can be adjusted. On the other hand, the smaller the value of the spring constant, the narrower the adjustable range becomes, or the longer the overall length of the spring becomes necessary, so it is set appropriately according to the desired adjustable range. In Table 1, the spring constant of such a fine adjustment specification (second biasing part) is 0.00004 to 0.0001 (×10). 3 N / mm) is one example.

[0065] Next, Table 1 shows the specifications for diaphragm 131c, including the type of specification, the orientation of the convexity in the unpressurized state, the reversal pressure (MPa), the number of stacked disc members (pieces), and the spring constant (×10). 3 The pressure (N / mm) is indicated. Three types of specifications are indicated: normal pressurized specification (first diaphragm), high-pressure pressurized specification (second diaphragm), and negative pressure specification (third diaphragm). Regarding the direction of the convexity in the unpressurized state, the normal pressurized specification (first diaphragm) and high-pressure pressurized specification (second diaphragm), both of which are for pressurization detection, are in the first state, convex inward into the space. On the other hand, the negative pressure specification (third diaphragm), which is for negative pressure detection, is in the second state, convex outward into the space. The reversal pressure (MPa) for each specification is 4 to 7 MPa or less for the normal pressurized specification (first diaphragm), 10 MPa or more for the high-pressure pressurized specification (second diaphragm), and negative pressure for the negative pressure specification (third diaphragm). The number of stacked disc members in each specification depends on the thickness of the disc members, but generally, it is 1 to 9 for normal pressure specifications (first diaphragm), 10 or more for high pressure specifications (second diaphragm), and 1 to several for negative pressure specifications (third diaphragm). Then, the spring constant (×10) for each specification according to these conditions is determined. 3The spring constant (N / mm) is typically 0.06-16 for standard pressurized specifications (first diaphragm), 14-55 for high-pressure pressurized specifications (second diaphragm), and 0.09-0.19 for negative-pressure specifications (third diaphragm). The above values ​​for spring constants represent the spring constant of a single disc member (=diaphragm) for diaphragms made of a single disc member. For diaphragms made of multiple disc members, the values ​​represent the spring constant of the diaphragm formed by stacking those multiple disc members.

[0066] The pressure switch 1 of the first embodiment described above can achieve the following effects. That is, even if there is variation in the reversal pressure of the diaphragm 131c, this variation can be suppressed by adjustment in the reversal pressure adjustment unit 15. In other words, the pressure switch 1 described above can set the reversal pressure required for the reversal operation of the diaphragm 131c with high precision.

[0067] Furthermore, according to this embodiment, the reversal pressure is adjusted by adjusting the biasing force directly applied to the diaphragm 131c from the biasing unit 14. Compared to configurations in which the reversal pressure is indirectly adjusted by applying a load to peripheral members other than the diaphragm, such as a stopper, this configuration makes it possible to directly adjust the reversal pressure with a low load. As a result, it is possible to improve the accuracy of the reversal pressure adjustment itself, reduce the cost of the adjustment structure, and save space for the installation of the adjustment structure. In addition, since the biasing unit 14 directly and elastically absorbs the reversal impact of the diaphragm 131c, it is also possible to improve the durability of the diaphragm 131c and the durability of the contact structure in the switch unit 12.

[0068] In this embodiment, the biasing unit 14 is configured to have a coil spring 141 as a compression spring provided in a compressed state with respect to the operating direction D11 of the diaphragm 131c. The reversal pressure adjustment unit 15 adjusts the biasing force on the diaphragm 131c by adjusting the amount of compression of the coil spring 141. With this configuration, the reversal pressure of the diaphragm 131c can be effectively adjusted by adjusting the amount of compression of the coil spring 141.

[0069] Furthermore, in this embodiment, the reversal pressure adjustment unit 15 is a screw member that adjusts the biasing force by the biasing unit 14 by changing the amount of screwing into the female screw. With this configuration, the biasing force can be adjusted by the simple operation of changing the amount of screwing into the male screw, that is, the amount of compression of the coil spring 141 as a compression spring can be adjusted.

[0070] Furthermore, in this embodiment, the reversal pressure adjustment unit 15 is a member that presses the switch-side spring end 141b of the coil spring 141 and allows the operating shaft 132 to move relative to it in the operating direction D11. The reversal pressure adjustment unit 15 adjusts the amount of compression of the coil spring 141 by increasing or decreasing the relative distance between the diaphragm-side spring end 141a and the switch-side spring end 141b of the coil spring 141. With this configuration, the amount of compression of the coil spring 141 can be effectively adjusted by pressing the switch-side spring end 141b with the reversal pressure adjustment unit 15 without affecting the operating shaft 132.

[0071] Furthermore, in this embodiment, the stopper retainer 134 of the drive unit 13 has a female thread on the inner circumferential surface 134a-1 of the through hole 134a through which the operating shaft 132 passes, and the reverse pressure adjustment unit 15 has a male thread on its outer circumferential surface 152 around the central axis X1. The reverse pressure adjustment unit 15 adjusts the amount of compression of the coil spring 141 by increasing or decreasing the relative distance between the diaphragm-side spring end 141a and the switch-side spring end 141b by changing the amount of screwing into the through hole 134a. With this configuration, the posture of the reverse pressure adjustment unit 15 can be stabilized by screwing the stopper retainer 134 into the through hole 134a, while the amount of compression of the coil spring 141 can be precisely adjusted by changing the amount of screwing.

[0072] Furthermore, in this embodiment, the through hole 134a in the stopper retainer 134 has a diameter that allows the coil spring 141 to pass through. The reversal pressure adjustment unit 15 presses the switch-side spring end 141b of the coil spring 141, which is at least partially housed inside the through hole 134a. With this configuration, since the coil spring 141 is pressed while at least partially housed in the through hole 134a, the posture of the coil spring 141 is also stabilized, allowing for more precise adjustment of the compression amount.

[0073] Furthermore, in this embodiment, the contact biasing piece 142, which is sandwiched between the operating shaft 132 and the diaphragm 131c and biased by the coil spring 141, directly biases the diaphragm 131c with the biasing force from the coil spring 141. The contact biasing piece 142 also transmits the force in the operating direction D11 caused by the reversal movement of the diaphragm 131c to the operating shaft 132. With this configuration, by providing the contact biasing piece 142 in the biasing section 14, the contact area with the diaphragm 131c can be set independently of the size (specifically, the spring diameter) of the coil spring 141. This makes it possible to bias the diaphragm 131c while reducing the contact area with the diaphragm 131c and suppressing the influence on the reversal movement.

[0074] Furthermore, in this embodiment, the contact biasing piece 142 has a support portion 142a and a projection portion 142b. The support portion 142a is the part that contacts and supports the diaphragm-side spring end 141a of the coil spring 141 and the diaphragm-side shaft end 132b of the operating shaft 132. The projection portion 142b is the part that protrudes from the support portion 142a and contacts the diaphragm 131c. The support portion 142a is a plate-like portion that extends with a width capable of supporting the entire diaphragm-side spring end 141a, and the projection portion 142b is a rod-shaped projection whose cross-sectional area in the direction intersecting the operating direction D11 is smaller than the cross-sectional area in the same direction of the support portion 142a. With this configuration, the diaphragm-side spring end 141a and the diaphragm-side shaft end 132b are supported by a sufficiently wide plate-shaped support portion 142a, thereby stabilizing the transmission of force to the operating shaft 132 and the reception of the biasing force from the coil spring 141. Furthermore, by making the cross-sectional area of ​​the projection 142b that contacts the diaphragm 131c smaller than the cross-sectional area of ​​the support portion 142a, the conventional diaphragm unit can be utilized in the following way. That is, in most conventional diaphragm units, a stopper through-hole is formed in the stopper that is slightly larger in diameter than the operating shaft. With the above configuration, by making the projection 142b a thin rod-shaped projection that can pass through this conventional stopper through-hole, interference with the inner periphery that occurs when the conventional stopper through-hole is used as is can be avoided even more effectively.

[0075] Furthermore, in this embodiment, the stopper through-hole 131b-1 in the stopper 131b of the diaphragm unit 131 is a through-hole that allows the rod-shaped projection 142b to pass through, and is smaller in diameter than the spring diameter of the coil spring 141. The rod-shaped projection 142b passes through this stopper through-hole 131b-1 and contacts the diaphragm 131c. The small-diameter stopper through-hole 131b-1 in this configuration corresponds to a conventional stopper through-hole that is slightly larger in diameter than the operating shaft 132. In other words, this configuration makes it possible to more effectively avoid interference with the inner periphery that occurs when using a conventional stopper through-hole as is.

[0076] Furthermore, in this embodiment, the spring constant of the biasing section 14 is smaller than the spring constant of the diaphragm 131c from the unpressurized state until the reversal operation occurs. With this configuration, compared to using a strong biasing section with a large spring constant, it is possible to miniaturize the surrounding structure and reduce costs accordingly. In addition, by using a weak biasing section 14 with a small spring constant as described above, it is possible to improve the precision of adjustment at the reversal pressure adjustment section 15 compared to using a strong biasing section with a large spring constant.

[0077] This concludes the description of the first embodiment, and next we will describe the second embodiment. In this second embodiment, the biasing mechanism for the diaphragm 131c differs from that of the first embodiment. The following description of the second embodiment will focus on the differences from this first embodiment.

[0078] Figure 2 is a cross-sectional view showing a pressure switch according to the second embodiment. In Figure 2, components equivalent to those of the first embodiment shown in Figure 1 are shown with the same reference numerals as in Figure 1, but only those necessary for explanation are shown. Hereafter, redundant explanations of these equivalent components will be omitted.

[0079] The pressure switch 2 in this embodiment is equivalent to that of the first embodiment in terms of basic switching operation. That is, pressurized fluid is introduced from the coupling 11 into the pressure space 13a of the drive unit 23 having a diaphragm unit 231. A force in the operating direction D11 along the central axis X1 is applied to the switch unit 12 as a driving force via the operating shaft 132 due to the reversing movement of the diaphragm 131c in response to the pressure change. In the switch unit 12, the driving force from the operating shaft 132 is received by the contact plate 124 inside the housing 122, and the conductive state of a pair of metal terminals 121 is switched by making the movable contact 123b of a pair of contacts 123 move toward and away from the fixed contact 123a.

[0080] In this embodiment, unlike the first embodiment described above, the biasing portion 24 is a coil spring, that is, a compression spring itself. The biasing portion 24 directly biases the diaphragm 131c by bringing the diaphragm-side spring end 241 of the coil spring into contact with the diaphragm 131c. For this reason, in the diaphragm unit 231 of this embodiment, the stopper 231b is provided with a stopper through-hole 231b-1 that is larger in diameter than the spring diameter of the coil spring, through which the coil spring acting as the biasing portion 24 can pass. The diaphragm-side spring end 241 of the coil spring acting as the biasing portion 24 passes through this large-diameter stopper through-hole 231b-1 and comes into contact with the diaphragm 131c.

[0081] On the other hand, the reverse pressure adjustment part 25, which is cap-shaped and has internal threads cut into the inner circumferential surface 134a-1 of the through hole 134a of the coil spring and the operating shaft 132 of the stopper retainer 134, and external threads cut into the outer circumferential surface 252, is screwed into it, just as in the first embodiment. That is, the reverse pressure adjustment part 25 is placed over the switch-side spring end 242 of the coil spring and presses against the switch-side spring end 242, adjusting the amount of compression of the coil spring by changing the amount it is screwed into the through hole 134a of the stopper retainer 134. However, in the reverse pressure adjustment part 25 of this embodiment, unlike in the first embodiment, two connecting grooves 251b are formed radially on the cap ceiling portion 251, flanking the central through hole 251a, for connecting a tool when changing the screwing amount.

[0082] In the pressure switch 2 of this embodiment, the adjustment to the target set reversal pressure is performed by the same procedure as in the first embodiment described above. That is, a diaphragm unit 231 equipped with a diaphragm 131c that reverses at a pressure lower than the set reversal pressure is incorporated into the drive unit 23, and the reversal pressure adjustment part 25 is screwed in to its maximum extent, for example, in an unpressurized state. Then, the internal pressure of the pressure space 13a is set to the set reversal pressure by introducing pressurized fluid, and the reversal pressure adjustment part 25 is loosened until the diaphragm 131c reverses. This reversal pressure adjustment part 25 is fixed to the stopper retainer 134, and the adjustment to the set reversal pressure is completed. After completion, the switch unit 12 and the shaft guide 133 are attached and the pressure switch 2 is assembled.

[0083] Similar to the first embodiment, the pressure switch 2 of the second embodiment described above also allows for highly accurate setting of the reversal pressure required for the reversal operation of the diaphragm 131c. Furthermore, this embodiment allows for direct adjustment of the reversal pressure with a low load, and, like the first embodiment, enables higher precision in the adjustment of the reversal pressure itself, lower costs for the adjustment structure, and space savings for the installation of the adjustment structure. Also, similar to the first embodiment, it is possible to improve the durability of the diaphragm 131c and the durability of the contact structure in the switch unit 12.

[0084] Furthermore, in this embodiment, the biasing portion 24 is the coil spring itself as a compression spring, and the diaphragm 131c is directly biased by bringing the diaphragm-side spring end 241 into contact with the diaphragm 131c. With this configuration, the biasing of the diaphragm 131c can be performed with a reduced number of parts. In addition, in this configuration, since no other members are interposed between the coil spring as the biasing portion 24 and the diaphragm 131c, the amount of movement of the reversal pressure adjustment portion 25 can be increased accordingly. Moreover, because no other members are interposed, a longer coil spring can be used as the biasing portion 24. These two points work together to increase the range of adjustment by the reversal pressure adjustment portion 25.

[0085] Furthermore, in this embodiment, the stopper 231b of the diaphragm unit 231 is provided with a stopper through-hole 231b-1 through which the coil spring, which serves as the biasing portion 24, can pass. The diaphragm-side spring end 241 passes through this stopper through-hole 231b-1 and contacts the diaphragm 131c. With this configuration, the drive unit 23 can effectively avoid interference with the diaphragm unit 231, including the diaphragm 131c, while allowing the coil spring to contact the diaphragm 131c.

[0086] This concludes the description of the second embodiment, and next we will describe the third embodiment. In this third embodiment, the installation method of the diaphragm 131c differs from that of the first embodiment, and consequently, the biasing method and the adjustment method of the reversal pressure also differ from those of the first embodiment. The third embodiment will be described below, focusing on the differences from this first embodiment.

[0087] Figure 3 is a cross-sectional view showing a pressure switch according to the third embodiment. In Figure 3, components equivalent to those of the first embodiment shown in Figure 1 are shown with the same reference numerals as in Figure 1, but only those necessary for explanation are shown. In the following, redundant explanations of these equivalent components will be omitted.

[0088] The pressure switch 3 in this embodiment is equivalent to that of the first embodiment in terms of basic switching operation. That is, pressurized fluid is introduced from the coupling 11 into the pressure space 33a adjacent to the diaphragm 131c. A force in the operating direction D11 caused by the reversing movement of the diaphragm 131c in response to the pressure change is applied to the switch unit 12 as a driving force. The switch unit 12 receives this driving force at the contact plate 124 inside the housing 122, and the conductive state of the pair of metal terminals 121 is switched by making the movable contact 123b of the pair of contacts 123 move toward and away from the fixed contact 123a.

[0089] In this embodiment, the drive unit 33 is configured to support the diaphragm 131c and, instead of the diaphragm unit 131 described above, has the following space-side block 331, stopper block 332, and connecting portion 333.

[0090] The space-side block 331 is a block member that partitions the pressure space 33a between itself and the diaphragm 131c, and the joint 11 is provided on this space-side block 331. The stopper block 332 is a block member positioned on the switch unit 12 side when viewed from the diaphragm 131c. This stopper block 332 sandwiches the diaphragm 131c between itself and the space-side block 331 and suppresses the displacement of the diaphragm 131c when it is reversed towards the switch to a predetermined amount. The diaphragm 131c, space-side block 331, and stopper block 332 are connected at a joint portion 334 near the outer circumference of the diaphragm 131c, with the diaphragm 131c sandwiched between the space-side block 331 and the stopper block 332. The connecting portion 333 is a thin, bottomed cylindrical member that connects the space-side block 331, diaphragm 131c, and stopper block 332, which are connected in this way, to the switch unit 12. The connecting portion 333 has an annular bottom wall 333a through which the joint 11 passes, and houses the space-side block 331, the diaphragm 131c, and the stopper block 332 within the cylinder. In this housed state, it is crimped to the opening 122b side of the housing 122 of the switch unit 12 by a crimping plate 333b, which is the opening on the switch side. The joint 11 and the space-side block 331 are each formed from separate components and connected by brazing or the like, but this is not the only option, and the joint 11 and the space-side block 331 may be formed integrally by, for example, machining.

[0091] Furthermore, in this embodiment, similar to the second embodiment described above, the diaphragm-side shaft end 132b of the operating shaft 132 directly contacts the diaphragm 131c. The biasing portion 34 is the coil spring itself as a compression spring, and the diaphragm-side spring end 341 contacts the diaphragm 131c, thereby directly biasing the diaphragm 131c.

[0092] The stopper block 332 has a through hole 332a on its inner circumferential surface 332a-1 that penetrates in the operating direction D11 so as to allow the coil spring, which serves as a biasing part 34, to pass through to the inside along with the operating shaft 132. The reversal pressure adjustment part 35 has a hexagonal plate-shaped head plate 351 and a cylindrical part 352 that protrudes from the head plate 351 toward the diaphragm 131c. In the center of the cylindrical part 352 is a through hole 352a through which the operating shaft 132 can move toward the operating direction D11 along the central axis X1. Furthermore, the cylindrical part 352 is provided with a spring housing annular groove 352b that opens toward the diaphragm 131c and houses the switch side of the coil spring, which serves as a biasing part 34, from the switch side spring end 342. Furthermore, the outer circumferential surface 352c of the cylindrical portion 352 has a male thread that engages with the female thread in the through hole 332a of the stopper block 332. The reversal pressure adjustment unit 35 is configured such that the switch side of the coil spring, which acts as the biasing portion 34, is housed in the spring housing annular groove 352b, and the cylindrical portion 352 is screwed into the through hole 332a of the stopper block 332. The reversal pressure adjustment unit 35 then adjusts the amount of compression of the coil spring by increasing or decreasing the relative distance between the diaphragm-side spring end 341 and the switch-side spring end 342 by changing the amount the cylindrical portion 352 is screwed into the through hole 332a. The change in the amount of screwing in the reversal pressure adjustment unit 35 is performed by gripping the hexagonal plate-shaped head plate 351.

[0093] In the pressure switch 3 of this embodiment, the adjustment to the target set reversal pressure is performed by the same procedure as in the first and second embodiments described above. That is, the drive unit 33, which has a diaphragm 131c that reverses at a pressure lower than the set reversal pressure, is assembled with the switch unit 12 removed. Then, the reversal pressure adjustment part 35 is screwed in to its maximum extent, for example, in an unpressurized state. After that, the internal pressure of the pressure space 33a is set to the set reversal pressure by introducing pressurized fluid, and the reversal pressure adjustment part 35 is loosened until the diaphragm 131c reverses. This reversal pressure adjustment part 35 is fixed to the stopper block 332, and the adjustment to the set reversal pressure is completed. After completion, the pressure switch 3 is assembled by connecting it to the switch unit 12 via the connecting part 333.

[0094] Similar to the first embodiment, the pressure switch 3 of the third embodiment described above also allows for high-precision setting of the reversal pressure required for the reversal operation of the diaphragm 131c. Furthermore, this embodiment allows for direct adjustment of the reversal pressure with a low load, and, like the first embodiment, enables high-precision adjustment of the reversal pressure itself, reduces the cost of the adjustment structure, and saves installation space for the adjustment structure. Also, similar to the first embodiment, it is possible to improve the durability of the diaphragm 131c and the durability of the contact structure in the switch unit 12.

[0095] Furthermore, in this embodiment, the drive unit 33 has a configuration in which the diaphragm 131c is sandwiched between the space-side block 331 and the stopper block 332, and connected to the switch unit 12 by a connecting portion 333. The reversal pressure adjustment portion 35 adjusts the amount of compression of the coil spring, which acts as a biasing portion 34, by changing the amount of screwing into the through hole 332a of the stopper block 332. With this configuration, the amount of compression of the coil spring can be adjusted by changing the amount of screwing into the through hole 332a of the stopper block 332, while effectively utilizing the diaphragm 131c holding structure in the drive unit 33.

[0096] Furthermore, in this embodiment, the through hole 332a of the stopper block 332 has a diameter that allows the coil spring, which acts as a compression spring and is the biasing part 34, to pass through. The reversal pressure adjustment part 35 then presses the switch-side spring end 342 of the coil spring, which is at least partially housed inside the through hole 332a. With this configuration, the compression amount can be adjusted more precisely by stabilizing the posture of the coil spring.

[0097] Furthermore, the first to third embodiments described above merely represent typical forms of pressure switches, and pressure switches are not limited to these and can be implemented in various modified forms.

[0098] For example, in the first to third embodiments described above, normally closed type pressure switches 1 to 3 that transition from an ON state to an OFF state in response to the operation of the operating shaft 132 are exemplified as examples of pressure switches. However, the pressure switch is not limited to these, and may also be a normally open type switch that transitions from an OFF state to an ON state in response to the operation of the operating shaft.

[0099] Furthermore, in the first to third embodiments described above, pressure switches 1, 2, and 3 are exemplified as examples of pressure switches, each comprising a pair of contacts 123 and a pair of metal terminals 121 corresponding one-to-one, with the metal terminals 121 being turned on / off by the contacts 123 being opened and closed. However, pressure switches are not limited to these, and the number of contacts can be set to any number as long as there are multiple contacts, including movable contacts. Also, the switch operation is not limited to on / off operation by the contacts opening and closing, but may be a switching operation, for example, where the connection destination of one movable contact is switched between multiple fixed contacts.

[0100] Furthermore, in the first to third embodiments described above, a covered cylindrical housing 122 is exemplified as an example of a housing in the switch unit. However, the housing is not limited to this, and any shape can be adopted depending on the application, installation location, etc.

[0101] Furthermore, in the first and second embodiments described above, pressure switches 1 and 2 are exemplified as examples of pressure switches, in which a female thread for reversal pressure adjustment is formed on a stopper retainer 134 that holds the housing 122 of the switch unit 12. In the third embodiment, pressure switch 3 is exemplified in which a female thread for reversal pressure adjustment is formed on a stopper block 332 that acts as a stopper for the diaphragm 131c. However, the pressure switch is not limited to these, and for example, a female thread for reversal pressure adjustment may be formed on a guide member of the operating shaft, such as the shaft guide 133 exemplified in Figures 1 and 2. In this case, in the first and second embodiments, the stopper retainer 134 may be omitted by modifying the connecting frame 137 to directly hold the housing 122 of the switch unit 12. In the third embodiment, which does not originally have a stopper retainer, the stopper block 332 may also serve as a shaft guide, and the reversal pressure adjustment section 35 may be modified to only perform the function of adjusting the reversal pressure.

[0102] Furthermore, in the first to third embodiments described above, pressure switches 1, 2, and 3 are exemplified as examples of pressure switches, in which the reversal pressure is adjusted to the set reversal pressure by a procedure in which the diaphragm 131c is biased to reverse at a pressure higher than the set reversal pressure, and then the biasing force is reduced. After setting, the set reversal pressure is maintained by fixing the reversal pressure adjustment units 15, 25, and 35. However, the pressure switches are not limited to these, and the procedure for adjusting the diaphragm's reversal pressure to the set reversal pressure may be performed by any procedure other than the above procedure. Also, the reversal pressure adjustment unit after setting may not be fixed in any way, and the reversal pressure may be made adjustable again once it has been set.

[0103] Furthermore, in the first to third embodiments described above, examples of reversal pressure adjustment sections 15, 25, and 35 are provided in each embodiment. In the first embodiment, a reversal pressure adjustment section 15 is provided with two connecting holes 151b for tool connection during adjustment, and in the second embodiment, a reversal pressure adjustment section 25 is provided with two connecting grooves 251b. In the third embodiment, a reversal pressure adjustment section 35 is provided with a hexagonal plate-shaped head plate 351 for gripping during adjustment. However, the reversal pressure adjustment section is not limited to these, and any configuration can be adopted for the tool connection and gripping configuration during adjustment.

[0104] Furthermore, in the first to third embodiments described above, pressure switches 1, 2, and 3 are exemplified as examples of pressure switches, in which the biasing parts 14, 24, and 34 are configured to have coil springs as compression springs, and the biasing force is adjusted by adjusting the amount of compression. However, the pressure switch is not limited to these, and may also use a tension spring as the biasing part, and the biasing force may be adjusted by adjusting the amount of tension. However, as described above, the reversal pressure of the diaphragm 131c can be effectively adjusted by adjusting the amount of compression of the compression spring. In the first to third embodiments described above, a coil spring is exemplified as an example of a compression spring, however, the compression spring is not limited to this, and may also be a compression spring other than a coil spring, such as a leaf spring.

[0105] Furthermore, in the first to third embodiments described above, as an example of a reversal pressure adjustment unit, reversal pressure adjustment units 15, 25, and 35 are provided as screw members that adjust the biasing force by the biasing units 14, 24, and 34 by changing the amount of screwing into the female screw. However, the reversal pressure adjustment unit is not limited to this, and its specific adjustment method is not limited. However, as mentioned above, the reversal pressure adjustment units 15, 25, and 35 as screw members allow for adjustment of the biasing force by simple operation.

[0106] Furthermore, in the first to third embodiments described above, as an example of a reversal pressure adjustment unit, reversal pressure adjustment units 15, 25, and 35 are provided that press the switch-side spring ends 141b, 242, and 342 of the compression spring and allow the operating shaft 132 to pass through so as to be relatively movable. These reversal pressure adjustment units 15, 25, and 35 adjust the amount of compression of the compression spring by increasing or decreasing the relative distance between the diaphragm-side spring ends 141a, 241, and 341 and the switch-side spring ends 141b, 242, and 342. However, the reversal pressure adjustment unit is not limited to these, and its specific shape and compression method are not restricted as long as the amount of compression of the compression spring can be adjusted. However, as described above, with the above-mentioned reversal pressure adjustment units 15, 25, and 35 that allow the operating shaft 132 to pass through and press the switch-side spring ends 141b, 242, and 342, the amount of compression of the coil spring can be effectively adjusted without affecting the operating shaft 132. Furthermore, as an example of such a reversal pressure adjustment section, the first to third embodiments described above illustrate reversal pressure adjustment sections 15, 25, and 35 having a cap shape that fits over one end of the coil spring. However, the reversal pressure adjustment section is not limited to these. The shape of the reversal pressure adjustment section can be other than a cap shape, such as a plate shape or a block shape. Also, the pressing method of the switch-side spring end is not limited to the method of pressing in direct contact with the pressing point, as in the first to third embodiments. The pressing method by the reversal pressure adjustment section may be, for example, a method of pressing with an intervening object such as a washer to suppress rotation between it and the switch-side spring end.

[0107] Furthermore, in the first and second embodiments described above, pressure switches 1 and 2 are exemplified as examples of pressure switches, in which a male-threaded reversal pressure adjustment unit 15, 25 is screwed into a female-threaded through hole 134a in a stopper retainer 134. In the third embodiment, a pressure switch 3 is exemplified in which a male-threaded reversal pressure adjustment unit 35 is screwed into a female-threaded through hole 332a in a stopper block 332. In these pressure switches 1, 2, and 3, the amount of compression of the coil spring is adjusted by changing the amount of screwing in the reversal pressure adjustment units 15, 25, and 35. However, the pressure switches are not limited to these, and the specific manner in which the amount of compression of the coil spring is adjusted by the reversal adjustment unit is not limited. However, as described above, the amount of compression can be precisely adjusted while stabilizing the position of the reversal pressure adjustment units 15, 25, and 35 by screwing them into the through holes 134a and 332a. Furthermore, as described above, according to the adjustment method illustrated in the third embodiment, the amount of compression can be adjusted while effectively utilizing the holding structure of the diaphragm 131c in the drive unit 33.

[0108] Furthermore, in the first to third embodiments described above, pressure switches 1, 2, and 3 are exemplified as examples of pressure switches, in which large-diameter through holes 134a and 332a with female threads are provided in the stopper retainer 134 and stopper block 332, respectively. In these pressure switches 1, 2, and 3, the reverse pressure adjustment parts 15, 25, and 35 with male threads press against the switch-side spring ends 141b, 242, and 342 of a coil spring, at least partially housed in the large-diameter through holes 134a and 332a. However, pressure switches are not limited to these. In a pressure switch, for example, a compression spring such as a coil spring may not be housed in the through holes of the stopper retainer or stopper block, and the reverse pressure adjustment part may press against the switch-side spring end outside the through hole. However, as described above, the amount of compression can be adjusted more precisely when the reverse pressure adjustment part presses against the switch-side spring end with a compression spring such as a coil spring housed in the through hole.

[0109] Furthermore, in the first embodiment described above, as an example of a biasing part, a biasing part 14 is provided which is configured to have a coil spring 141 and a contact biasing piece 142, and which directly biases the diaphragm 131c with the contact biasing piece 142. However, the biasing part is not limited to this, and for example, as illustrated in the second and third embodiments, the coil spring itself may be used as the biasing part 24, 34, and the diaphragm 131c may be directly biased with this coil spring. However, as described above, the configuration in which the diaphragm 131c is biased with the contact biasing piece 142 makes it possible to bias the diaphragm 131c while reducing the contact area with the diaphragm 131c and suppressing the influence on the reversal operation.

[0110] Furthermore, in the first embodiment described above, as an example of a contact biasing piece in the biasing section, a contact biasing piece 142 is provided which has a support portion 142a that contacts and supports the coil spring 141 and the operating shaft 132, and a projection portion 142b that contacts the diaphragm 131c. However, the contact biasing piece is not limited to this, and any shape can be adopted for its specific form. However, as described above, the contact biasing piece 142 having the support portion 142a and the projection portion 142b can stabilize the transmission of force to the operating shaft 132 and the reception of the biasing force from the coil spring 141.

[0111] Furthermore, in the first embodiment described above, an example of a projection on the contact biasing piece is a rod-shaped projection 142b whose cross-sectional area is smaller than that of the support portion 142a. However, the projection on the contact biasing piece is not limited to this, and its cross-sectional area can be set to any area. However, as described above, a rod-shaped projection 142b with a small cross-sectional area can more effectively avoid interference with the inner periphery when the stopper through-hole of a conventional diaphragm unit is used as is.

[0112] Furthermore, in the first embodiment described above, as an example of a contact biasing piece in the biasing section, a contact biasing piece 142 is provided which has a rod-shaped projection 142b that passes through a stopper through-hole 131b-1, which has a smaller diameter than the spring diameter of the coil spring 141, and contacts the diaphragm 131c. However, the contact biasing piece is not limited to this, and the stopper through-hole to be penetrated can be set as appropriate. However, as described above, by making the projection 142b of the contact biasing piece 142 able to pass through the small-diameter stopper through-hole 131b-1, the conventional stopper through-hole 131b-1 can be used more effectively.

[0113] Furthermore, in the second and third embodiments described above, a biasing section 24, 34 is exemplified as an example of a biasing section, which uses a compression spring (coil spring) itself and directly biases the diaphragm 131c by contacting it. However, the biasing section is not limited to this, and may, for example, transmit the biasing force of the compression spring to the diaphragm via other members, as exemplified in the first embodiment. However, as described above, by using the compression spring itself as the biasing section 24, 34, the biasing of the diaphragm 131c can be achieved with a reduced number of parts.

[0114] Furthermore, in the second embodiment described above, a pressure switch 2 is exemplified as an example of a pressure switch, in which a stopper through-hole 231b-1 is provided in the stopper 231b of the diaphragm unit 231, through which a compression spring (coil spring) acting as a biasing part 24 can pass. However, the pressure switch is not limited to this, and even if the diaphragm is directly biased by a compression spring acting as a biasing part, a configuration such as that exemplified in the third embodiment may also be used. In this configuration, the diaphragm 131c is not unitized but is held sandwiched between the space-side block 331 and the stopper block 332. A through-hole 332a is provided in the stopper block 332 for passing the compression spring acting as a biasing part 34 to the diaphragm 131c. However, as described above, by providing the stopper through-hole 231b-1 for passing the compression spring through the stopper 231b, the compression spring can be brought into contact with the diaphragm 131c while making use of the widely used unit configuration.

[0115] Furthermore, in the third embodiment described above, a pressure switch 3 is exemplified as an example of a pressure switch in which a stopper block 332, which sandwiches a diaphragm 131c between itself and a space-side block 331, is provided with a through hole 332a for a compression spring (coil spring). In this configuration, a female thread is cut into the through hole 332a of the stopper block 332, and a reverse pressure adjustment part 35, which has a male thread, is screwed into the through hole 332a. The amount of compression of the compression spring, which acts as a biasing part 34, is adjusted by changing the amount of screwing. However, the pressure switch is not limited to this, and for example, as exemplified in the first and second embodiments, a configuration in which the diaphragm 131c is unitized and held may also be adopted. In this configuration, a through hole 134a for adjusting the amount of compression of the compression spring is provided in the stopper retainer 134 adjacent to the diaphragm unit 131, 231 on the switch side. However, as mentioned above, by not unitizing the diaphragm 131c and instead providing a through hole 332a in the stopper block 332 for adjusting the amount of compression, it is possible to adjust the amount of compression while effectively utilizing the holding structure other than the unit.

[0116] Furthermore, in the first to third embodiments described above, pressure switches 1, 2, and 3 are exemplified as examples of pressure switches in which the spring constants of the biasing parts 14, 24, and 34 are smaller than the spring constant of the diaphragm 131c. However, the pressure switch is not limited to this, and may also be one in which the spring constant of the biasing part is equal to or greater than the spring constant of the diaphragm. However, as mentioned above, by using weak biasing parts 14, 24, and 34 with small spring constants, it is possible to miniaturize the surrounding structure, reduce costs, and improve the precision of adjustment. In the first to third embodiments described above, Table 1 is provided as an example of various numerical values ​​related to such spring constants. However, the various numerical values ​​related to spring constants are not limited to these, and can be appropriately set according to the operating environment of the pressure switch, etc. [Explanation of Symbols]

[0117] 1,2,3 Pressure switch 11 Fittings 12 Switch Units 13, 23, 33 Drive Unit 13a, 33a Pressure space 14,24,34 Encouraging parts 15, 25, 35 Reversal pressure adjustment section 121 Metal terminal 121a Terminal 1 121a-1, 121b-1 Folded section 121b 2nd terminal 122 Housing 122a Circular lid 122b aperture 123 Contacts 123a Fixed contact 123b Movable contact 124 Contact plate 124a Fixed part 124b Moving parts 124c Load-bearing section 131,231 Diaphragm Unit 131a Cap 131b, 231b Stopper 131b-1, 231b-1 Stopper through hole 131c diaphragm 131d,334 Joint 132 Operating shaft 132a Switch-side shaft end 132b Diaphragm side shaft end 133 Axis guide 133a Guide hole 134 Stopper retainer 134a,332a Passing hole 134a-1,332a-1 Inner surface 134b, 137b, 333b Crimping Plate 135 Switch-side O-ring 136 Diaphragm-side O-ring 137 Connecting Frame 137a Main frame 141 Coil spring 141a, 241, 341 Diaphragm-side spring end 141b, 242, 342 Switch-side spring end 142 Contact biasing piece 142a Support part 142b Protrusion 151,251 Cap ceiling section 151a,251a,352a through hole 151b Connection hole 152,252,352c Outer surface 251b Connection groove 331 Spatial side block 332 Stopper Block 333 Connection section 333a Circular base wall 351 Head plate 352 Cylindrical section 352b Spring housing annular groove D11 Direction of movement D111 Push-up direction D12 Extending direction X1 center axis

Claims

1. A diaphragm that forms part of a partition wall dividing a pressure space and reverses between a first state convex inward and a second state convex outward in response to pressure changes in the pressure space, An operating shaft is positioned outside the space of the diaphragm, extending in a direction intersecting the diaphragm, and moving in accordance with the reversal movement of the diaphragm; A switch unit comprising a housing containing a plurality of contacts, including a movable contact that is movable by receiving as a driving force from the operating shaft the force in the direction of the reversal movement generated on the operating shaft by the reversal movement of the diaphragm, A biasing unit is provided separately from the aforementioned operating shaft, and capable of directly biasing the diaphragm in the direction of operation, A reversal pressure adjustment unit adjusts the reversal pressure required for the reversal operation of the diaphragm by adjusting the biasing force provided by the biasing unit, A pressure switch characterized by having the following features.

2. The biasing portion is provided in a compressed state in the direction of operation and is configured to have a compression spring that generates the biasing force on the diaphragm. The pressure switch according to claim 1, characterized in that the reversal pressure adjustment unit adjusts the biasing force by adjusting the amount of compression of the compression spring in the operating direction.

3. The pressure switch according to claim 2, wherein the reversal pressure adjustment unit is a screw member having a male screw that screws into a female screw provided on a predetermined member, and the biasing force by the biasing unit is adjusted by changing the amount of screwing into the female screw.

4. The pressure switch according to claim 3, wherein the reversal pressure adjustment part is a member that presses the switch-side spring end of the compression spring on the opposite side of the diaphragm in the direction of operation, and through which the operating shaft is relatively movable in the direction of operation, and adjusts the amount of compression of the compression spring by increasing or decreasing the relative distance between the diaphragm-side spring end and the switch-side spring end of the compression spring.

5. The switch unit further comprises an intermediate block positioned between the housing and the diaphragm, The intermediate block is provided with a through hole that penetrates in the direction of operation so as to allow the operating shaft to pass through to the inside, and has the internal threads cut into its inner surface. The pressure switch according to claim 4, characterized in that the reversal pressure adjustment section has a male thread that screws into the female thread on its outer circumferential surface around a central axis in line with the operating direction, and the amount of compression of the compression spring is adjusted by increasing or decreasing the relative distance between the diaphragm-side spring end and the switch-side spring end by changing the amount of screwing into the through hole.

6. The through hole in the intermediate block is a hole with a diameter that allows both the operating shaft and the compression spring to pass through. The pressure switch according to claim 5, characterized in that the reversal pressure adjustment unit presses the switch-side spring end of the compression spring, which is at least partially housed inside the through hole.

7. The biasing portion is further configured to include a contact biasing piece that is sandwiched between the operating shaft and the diaphragm and is in contact with the diaphragm, and is biased by the compression spring. The pressure switch according to claim 2, characterized in that the contact biasing piece directly biases the diaphragm with the biasing force from the compression spring and transmits the force in the direction of operation due to the reversal movement of the diaphragm to the operating shaft.

8. The contact biasing piece has a support portion that contacts and supports the diaphragm-side spring end of the compression spring, which is on the diaphragm side, and the diaphragm-side shaft end of the operating shaft, which is on the diaphragm side, and a projection that protrudes from the support portion and contacts the diaphragm. The support portion is a part that extends with a width sufficient to support the entire end of the diaphragm-side spring, The pressure switch according to claim 7, characterized in that the projection is a rod-shaped projection whose cross-sectional area in the direction intersecting the direction of operation is smaller than the cross-sectional area of ​​the support portion in the direction intersecting the direction of operation.

9. The pressure switch according to claim 2, characterized in that the biasing portion is the compression spring itself, and the diaphragm is directly biased by bringing the diaphragm-side spring end of the compression spring, which is on the diaphragm side, into contact with the diaphragm.

10. A space-side block that partitions the pressure space between the diaphragm and the space-side block, A stopper block is positioned on the switch unit side as seen from the diaphragm, sandwiching the diaphragm between itself and the space-side block, and suppressing the displacement of the diaphragm to a predetermined amount in the second state, The space-side block, the diaphragm, and the stopper block are further connected to the switch unit by a connecting portion, The stopper block is provided with a through hole that penetrates in the direction of operation so as to allow the operating shaft to pass through to the inside, and has the female threads cut into its inner circumferential surface. The pressure switch according to claim 4, characterized in that the reversal pressure adjustment section has a male thread that screws into the female thread on its outer circumferential surface around a central axis in line with the operating direction, and the amount of compression of the compression spring is adjusted by increasing or decreasing the relative distance between the diaphragm-side spring end and the switch-side spring end by changing the amount of screwing into the through hole.

11. The through hole in the stopper block is a hole with a diameter that allows both the operating shaft and the compression spring to pass through. The pressure switch according to claim 10, characterized in that the reversal pressure adjustment unit presses the switch-side spring end of the compression spring, which is at least partially housed inside the through hole.

12. The diaphragm, in an unpressurized state where no pressure is applied to the diaphragm, is in one of the first or second states, and in response to the pressure change, it reverses to the other state. The pressure switch according to claim 1, characterized in that the spring constant of the biasing portion is smaller than the spring constant of the diaphragm from the unpressurized state until the reversal operation occurs.

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