Disclosure of Invention
Technical problem
However, in the above-described micro switch, for example, chattering phenomenon in which the movable contact 2a and the fixed contact 4 repeatedly contact and separate from each other is liable to occur from the OFF state in which the movable contact 2a and the fixed contact 4 are separated to the state before the pressing piece 5 is pressed and the leaf spring 3c is reversed. Therefore, it is difficult to stably maintain the on state of the movable contact 2a in the state before the leaf spring 3c is reversed. For example, when a micro switch is mounted on a device that is likely to generate an undesirable external force due to vibration, pressure fluctuation, or the like, such as a pressure responsive switch that detects the pressure of a refrigerant in a refrigeration cycle, this is likely to be obvious.
The invention aims to provide a micro switch and a pressure response switch which can stably maintain the conducting state of a contact.
Technical proposal
In order to solve the above-described problems and achieve the object, according to the present invention, there is provided a micro switch including a movable contact provided between a pair of fixed contacts, an operating shaft that moves in a forward and backward direction, and a switching member that performs a reversing operation to bring one or the other of the pair of fixed contacts into conduction with movement of the operating shaft, wherein the switching member includes an operating spring that is connected to the operating shaft, an operating spring that holds the movable contact, and a reversing spring that connects the operating spring and the operating spring, the operating spring is provided so as to be deformable with movement of the operating shaft, the reversing spring is provided so as to be able to apply a force to the operating spring in accordance with deformation of the operating spring, the operating spring is provided so as to be able to press the movable contact against one or the other of the pair of fixed contacts with the application of force, a range of movement of the operating shaft includes a reversing position where the reversing operation is generated after passing, a rigidity reducing member is provided to the operating spring, the rigidity reducing member is provided so as to be able to maintain the operating spring in a state where the one of the operating shaft is in a state where the reversing spring is pressed against the other of the operating shaft, and the operating spring is in a state where the reversing state is kept in which the operating shaft is deformed.
According to the present invention, by providing the rigidity reducing member in the working spring, the working spring can be placed in a deformed state when the working shaft is positioned at the reversing position, that is, in a state before the reversing operation is generated. When the working spring is in the deformed state, the urging force for maintaining the state in which the working spring presses the movable contact against the fixed contact can be generated by the reversing spring. Therefore, even before the reversing operation, the movable contact can be reliably maintained in a state of being pressed against the fixed contact, and even when an unexpected external force such as vibration or pressure fluctuation is generated, the chatter phenomenon or the like can be suppressed. Therefore, a micro switch capable of stably maintaining the conductive state of the contact can be provided.
In this case, the fixed contact may include a first fixed contact and a second fixed contact disposed on a backward side in the forward and backward direction with respect to the first fixed contact, the reverse position may include a first reverse position where the reverse operation is generated after the operation shaft passes toward the forward side in the forward and backward direction, and a second reverse position where the reverse operation is generated after the operation shaft passes toward the backward side, the movable contact may be pressed against the first fixed contact in a state where the operation shaft moving toward the forward side is located at the first reverse position, and the movable contact may be pressed against the second fixed contact in a state where the operation shaft moving toward the backward side is located at the second reverse position. According to this configuration, the present invention can be applied to a microswitch of a type in which the conduction destination of the movable contact is switched from the first fixed contact to the inversion operation of the second fixed contact (first inversion position) and the conduction destination of the movable contact is switched from the second fixed contact to the inversion operation of the first fixed contact (second inversion position), and the state in which the movable contact is pressed against the fixed contact can be maintained until the inversion operation is performed.
Preferably, the switching member includes an inner spring as the working spring extending in a crossing direction crossing the advancing and retreating direction and formed in a plate shape, an outer spring as the working spring surrounding the inner spring and formed in a plate shape, and the reversing spring, the inner spring includes an abutting portion abutting the working shaft, and the rigidity reducing member reduces the rigidity of the inner spring from a side where the abutting portion is located toward a side where a connecting portion with the reversing spring is located. According to this structure, the rigidity reducing member reduces the rigidity of the inner spring toward the side where the connecting portion is located, so that the side where the connecting portion of the inner spring is located can be deformed more easily than the side where the working shaft of the inner spring is located. This makes it easier to maintain the deformed state of the inner spring on the connecting portion side. Therefore, before the reverse rotation, the urging force of the outer spring against the reverse rotation spring is more easily maintained, and the state in which the outer spring presses the movable contact toward the fixed contact can be stably maintained. Further, according to this structure, the rigidity of the inner spring on the side of the working shaft is easily improved, and therefore the durability of the inner spring on the side of the working shaft can be improved.
The rigidity reducing member may be a hole penetrating in a plate thickness direction of the inner spring. According to this structure, the rigidity reducing member can be provided on the micro switch by a simple method of forming the hole portion on the inner spring.
In addition, it is preferable that the dimension of the hole portion in the width direction increases toward the connecting portion. According to this configuration, by increasing the width dimension of the hole portion toward the connecting portion, the volume of the inner spring can be reduced toward the connecting portion side and increased toward the abutting portion side. Therefore, the rigidity of the inner spring can be reduced toward the connecting portion side, and the connecting portion side in the inner spring can be deformed more easily than the operating shaft side in the inner spring. This makes it easier to maintain the deformed state of the inner spring on the connecting portion side.
Further, the rigidity reducing member may be constituted by a cutout portion that cuts the inner spring in the width direction. According to this structure, the rigidity reducing member can be provided on the microswitch by a simple method of forming the cutout portion by cutting the inner spring.
The pressure responsive switch of the present invention is characterized by comprising the above-described micro switch. With this configuration, the pressure responsive switch can be constructed by mounting the micro switch capable of stably maintaining the on state of the contact.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, a micro switch and a pressure responsive switch capable of stably maintaining the conductive state of a contact can be provided.
Detailed Description
An embodiment of the present invention will be described below. The micro switch 1 of the present embodiment is mounted on a pressure responsive switch 100 or the like that detects a pressure change of a fluid or a temperature change of the fluid, for example, and detects the pressure change or the temperature change of the fluid using a working medium as the fluid, for example, a refrigeration cycle, an automobile, or various control actuators.
In the following description, the axial direction of the working shaft 20 to be described later is indicated by an arrow Z in the drawings, and is referred to as "up-down direction Z". One side in the up-down direction Z is referred to as "lower side Z1", and the other side is referred to as "upper side Z2". The up-down direction Z is the "forward-backward direction" in the present invention, the lower side Z1 is the "forward side" in the present invention, and the upper side Z2 is the "backward side" in the present invention. The horizontal direction (the intersecting direction in the present invention) intersecting the vertical direction Z is indicated by an arrow X and an arrow Y, and is referred to as "front-rear direction X" and "left-right direction Y", respectively. One side in the front-rear direction X is referred to as "front side X1", the other side is referred to as "rear side X2", one side in the left-right direction Y is referred to as "left side Y1", and the other side is referred to as "right side Y2". These directions are defined for convenience of description, and do not necessarily coincide with the directions in the actual use state of the micro switch 1, and are not limited to the directions in the actual use state of the micro switch 1.
As shown in fig. 1, the pressure-responsive switch 100 includes a housing 110 having a substantially rectangular shape as a whole. The housing 110 includes a C-shaped main body frame 111 that opens to the lower side Z1, and a cover, not shown, that closes the opening of the main body frame 111, and accommodates therein various components such as a microswitch 1, which will be described later. The main body frame 111 is formed by bending a metal plate material, and includes a front wall 112, a side wall 113, a rear wall 114, and a top wall 115. A pair of elements 116, and a pair of joint pipes 117 connected to the pair of elements 116, respectively, are connected to the rear wall 114 of the housing 110. The element 116 includes an induction member such as a bellows or a diaphragm, not shown, inside. The sensing member is deformed or displaced in the front-rear direction X according to a pressure change of the pressure fluid introduced through the joint pipe 117.
A pair of left and right transmission members 118 and a pair of left and right switch members 119 are accommodated in the housing 110. The transmission member 118 includes a reinforcing plate 120 formed in a C-shape opened upward Z2 by bending a metal plate material, and a transmission member 121 is accommodated in the reinforcing plate 120. As an example of the transmission member 121, for example, a working plate 122 is provided, and the working plate 122 receives the force of deformation or displacement of the sensing member as an external force, and converts the external force into an operating force by rotating about a rotation axis 123, and transmits the operating force to a link 17 described later. The switch member 119 includes a plurality of contacts 40 described later, and receives the above-described operation force to change the conduction state of the contacts 40. The pair of switch members 119 are provided adjacent to the left-right direction Y, and constitute the double-type micro switch 1. Fig. 2 is a perspective view of the micro switch 1, and fig. 3 is a sectional view taken along the line A-A in fig. 2.
As shown in fig. 2, the microswitch 1 includes a box 10. The case portion 10 is formed of, for example, a resin material in a substantially cubic shape, and an accommodating space 11 for accommodating various members is formed therein. The rear wall 12 of the box 10 is formed with a connecting portion 13 protruding toward the rear side X2. The connection portion 13 is formed in a plate shape extending in the up-down direction Z, and is fixed to the top wall portion 115 of the housing 110 of the pressure-responsive switch 100. A rectangular box-shaped fixing member 15 is attached to the upper wall 14 of the box 10. In the present embodiment, the pair of fixing members 15 are mounted in a row in the left-right direction Y. A rotation shaft 16 extending in the left-right direction Y is fixed to a side wall of each of the fixing members 15, and a link 17 is rotatably attached to the rotation shaft 16 about an axis. Namely, a pair of links 17 are provided. In the present embodiment, "rotation" means forward and reverse rotation within a predetermined angle range about the rotation shaft 16. The link 17 is a work piece formed of a metal material in a plate shape, extends from the rotation shaft 16 to the front side X1, and is rotatably provided on one side a and the other side b around the rotation shaft 16.
The link 17 is biased to the other side b by a biasing force of a switching member 50 described later in an initial state shown in fig. 2, and extends obliquely so as to be positioned on the upper side Z2 from the rear end portion supported by the rotation shaft 16 toward the front end portion. The link 17 rotates to one side a around the rotation shaft 16 by receiving an external force. Examples of the external force include a force generated by a pressure change of the refrigerant in the refrigeration cycle. Such force is applied to a not-shown sensing member mounted on the pressure switch, and is transmitted to the link 17 via the transmission member 118. The receiving portion 18 is formed on the plate surface of the link 17. As shown in fig. 3, the receiving portion 18 is formed by projecting the intermediate portion of the plate surface of the link 17 in the front-rear direction X upward, and has a V-shaped cross-section surface that opens to the lower side Z1. The working shaft 20 whose axis extends in the up-down direction Z is supported by the receiving portion 18.
The working shaft 20 is a shaft member that converts the rotational movement of the link 17 into an advancing and retreating movement in the up-down direction Z, and acts on a switching member 50 described later by moving in the up-down direction Z. The working shaft 20 is connected to the box 10 so as to be movable forward and backward in the up-down direction Z in a state of being inserted through an insertion through hole 19 penetrating the upper wall 14 of the box 10 in the up-down direction Z. The upper end portion of the working shaft 20 constitutes a pressed portion 21 pressed by the link 17. In the present embodiment, the pressed portion 21 is slidably connected to the V-shaped inner surface of the receiving portion 18 of the link 17 and is pressed by the lower side Z1. On the other hand, the lower end portion of the working shaft 20 constitutes an engagement portion 22 that engages with a switching member 50 described later. The working shaft 20 is held by a seal member 30 closing a gap with the insertion through hole 19, and is connected to the box 10. The sealing member 30 is provided to hermetically seal between the working shaft 20 and the insertion through hole 19, and prevents external atmosphere or foreign matter in the microswitch 1 from entering the accommodation space 11 from between the working shaft 20 and the insertion through hole 19. In addition, the sealing member 30 may not be provided as long as the above-mentioned external atmosphere or foreign matter can be allowed to intrude into the accommodation space 11. That is, the inner diameter of the insertion through hole 19 can be reduced according to the outer diameter of the working shaft 20, and the working shaft 20 can be guided by the insertion through hole 19 of the upper wall 14 of the box 10.
The sealing member 30 is formed in a cylindrical shape from, for example, a resin material having flexibility. The upper end opening edge 31 of the seal member 30 covers the working shaft 20 in the circumferential direction around the shaft, and the lower end opening edge 32 of the seal member 30 covers the opening edge of the through hole 19, whereby the air tightness in the accommodation space 11 is set so as to have air tightness of at least several tens kPa from the side of the accommodation space 11, for example. With this configuration, even if the pressure-responsive switch 100 is used in a fluid environment having combustibility, it is possible to prevent the combustible fluid from invading into the accommodation space 11 and to prevent the risk of ignition due to spark generated by the operation of the micro switch 1. The setting of the air tightness of the housing space 11 is not limited to the above, and may be arbitrarily set according to the envisaged use environment. For example, when preventing invasion of foreign matter into the accommodation space 11 and allowing invasion of a gas fluid, the air tightness of the accommodation space 11 may be set to such an extent that invasion of foreign matter can be prevented.
As shown in fig. 3, a contact 40 is provided in the accommodation space 11 of the box 10. The contact 40 is a conductive member made of a conductive material, and includes a pair of fixed contacts 41 fixed in the housing space 11, and a movable contact 44 disposed between the pair of fixed contacts 41. The pair of fixed contacts 41 is constituted by a first fixed contact 42 and a second fixed contact 43. The first fixed contact 42 is fixed to the inner wall of the box 10 in a state facing the upper side Z2. The second fixed contact 43 is disposed on the upper side Z2 of the first fixed contact 42, and is fixed to the inner wall of the box 10 in a state facing the first fixed contact 42 toward the lower side Z1. The movable contact 44 is fixed to a contact holding portion 72 of the outer spring 70 described later, and is displaced to the upper side Z2 or the lower side Z1 to come into contact with the first fixed contact 42 or the second fixed contact 43, thereby being capable of conducting with the first fixed contact 42 or the second fixed contact 43. A switching member 50 for switching the on state of the movable contact 44 (contact 40) is provided between the working shaft 20 and the contact 40 in the accommodation space 11 of the case 10.
The switching member 50 is a portion that performs a reverse rotation operation in response to the movement of the working shaft 20 and that causes the movable contact 44 to be in conduction with one or the other of the first fixed contact 42 and the second fixed contact 43. As shown in fig. 3, the switching member 50 is, for example, a plate spring formed by bending a metal plate member, and includes a contact plate 51 fixed to the inner wall of the box 10. The contact plate 51 includes a bent portion 52 bent to the rear side X2 by being folded back from a position fixed to the inner wall of the case portion 10 toward the front side X1, a plate-shaped inner spring 60 (operating spring) extending continuously toward the front side X1 toward the left-right direction Y center portion of the bent portion 52 and extending in the front-rear direction X and the left-right direction Y (i.e., intersecting direction), an outer spring 70 (operating spring) formed in a plate shape so as to be continuous with the bent portion 52 and surrounding the inner spring 60, and a reversing spring 80 connecting the inner spring 60 and the outer spring 70. As shown in fig. 4, the inner spring 60 includes a wide portion 61 that constitutes a rear side X2 portion. The wide portion 61 is formed in a substantially rectangular shape in a plan view, and extends obliquely so as to be positioned on the upper side Z2 from the rear side X2 toward the front side X1 as shown in fig. 5.
The wide portion 61 has an engagement hole 62 penetrating in the vertical direction Z, and the engagement portion 22 of the working shaft 20 is engaged with the engagement hole 62 in a state inserted therethrough toward the lower side Z1. That is, the inner spring 60 is connected to the working shaft 20. Thus, the inner edge of the engagement hole 62 abuts against the outer surface of the working shaft 20, and forms an abutment 63. The narrow portion 64 having a smaller dimension in the left-right direction Y than the wide portion 61 is continuously formed on the front side X1 of the wide portion 61. The narrow portion 64 is formed in a substantially rectangular shape in plan view, and extends obliquely so as to be positioned on the upper side Z2 from the rear side X2 toward the front side X1. A first engagement protrusion 65 protruding toward the front side X1 is formed at the center of the front end edge of the narrow portion 64 in the left-right direction Y. A hole 90 penetrating in the up-down direction Z (plate thickness direction) is formed in the center portion of the plate surface of the narrow portion 64.
By forming the hole portion 90, the volume of the narrow portion 64 is reduced, and the rigidity of the inner spring 60 is reduced. That is, the hole portion 90 constitutes a rigidity reducing member in the present invention. In the present embodiment, the hole portion 90 is formed in a substantially regular triangle shape having an acute angle toward the side of the abutment portion 63 of the rear side X2. That is, the dimension of the hole portion 90 in the left-right direction Y increases toward the first connecting portion a. As a result, the volume of the front side X1 portion of the inner spring 60 becomes smaller as compared with the volume of the rear side X2 portion toward the front side X1, and in particular, the rigidity of the inner spring 60 decreases as going from the side of the abutment portion 63 of the inner spring 60 toward the front side X1 where the first connection portion a (connection portion) described later is located.
The outer spring 70 includes a pair of left and right side portions 71 extending continuously from the bent portion 52 toward the front side X1. The side portion 71 of the left side Y1 of the pair of side portions 71 is arranged at a distance from the end edge of the left side Y1 of the wide portion 61 of the inner spring 60 in the left-right direction Y, the side portion 71 of the right side Y2 of the pair of side portions 71 is arranged at a distance from the end edge of the right side Y2 of the wide portion 61 of the inner spring 60 in the left-right direction Y, and each side portion 71 extends toward the front side X1. A contact holding portion 72 is formed at the front end edge of each side portion 71, and extends so as to connect each side portion 71. The contact holding portions 72 are arranged at a distance from each other toward the front side X1 of the inner spring 60, and are formed in a plate shape having a width dimension which decreases in the lateral direction Y as the contact holding portions go toward the front side X1. As shown in fig. 5, a distal end portion of the contact holding portion 72 is located between the first fixed contact 42 and the second fixed contact 43, and a mounting hole 73 penetrating in the vertical direction Z is formed in the distal end portion. The movable contact 44 is fixed to the mounting hole 73 in a state of being inserted therethrough. That is, the outer spring 70 holds the movable contact 44. A substantially rectangular plate-like protruding portion 74 protruding toward the inward spring 60 is formed at the rear end edge of the contact holding portion 72. A second engagement protrusion 75 protruding toward the rear side X2 is formed at the center portion in the left-right direction Y of the rear end edge of the protruding portion 74, and the second engagement protrusion 75 is opposed to the first engagement protrusion 65 of the inner spring 60 in the front-rear direction X.
As shown in fig. 5, the reversing spring 80 is formed into a substantially U-shape opening downward Z1 by bending a metal plate member, and includes an upper wall portion 81, a rear wall portion 82, and a front wall portion 83. The upper wall portion 81 is formed in a substantially rectangular shape and extends in the front-rear direction X and the left-right direction Y. The rear wall 82 is curved from the rear edge of the upper wall 81 toward the lower side Z1, and is inclined so as to be slightly inward toward the lower side Z1. A first inclined portion 82a that is inclined so as to be located outside as going to the lower side Z1 is formed at the lower end portion of the rear wall portion 82. The front end edge of the narrow portion 64 of the inner spring 60 abuts against the boundary portion between the rear wall 82 and the first inclined portion 82a, and the first engagement protrusion 65 is inserted therethrough via a through hole, not shown. In this way, the boundary portion between the rear wall 82 and the first inclined portion 82a constitutes the first connecting portion a that is the connecting portion between the inner spring 60 and the reversing spring 80.
The front wall portion 83 is curved from the front end edge of the upper wall portion 81 toward the lower side Z1, and is inclined so as to be slightly inward as going toward the lower side Z1. A second inclined portion 83a that is inclined so as to be slightly positioned outside as going to the lower side Z1 is formed at the lower end portion of the front wall portion 83. Then, the boundary portion between the front wall portion 83 and the second inclined portion 83a abuts against the rear end edge of the protruding portion 74 of the outer spring 70, and the second engagement protrusion 75 is inserted therethrough via a through hole, not shown. In this way, the boundary portion between the front wall portion 83 and the second inclined portion 83a constitutes the second connecting portion B that is the connecting portion between the outer spring 70 and the reversing spring 80. The reversing spring 80 can contract in a direction to close the first and second connection portions a and B, and can generate a reversing spring load P1 in a direction to move the first and second connection portions a and B away from and open.
Next, the operation of the micro switch 1 will be described. Here, as an example of the operation, the microswitch 1 is mounted on the pressure responsive switch 100 for detecting the pressure of the refrigerant in the refrigeration cycle, and is described for detecting an abnormally high pressure. First, in an initial state in which the link 17 is not rotated, as shown in fig. 5, the movable contact 44 is in conduction with the first fixed contact 42. At this time, the reversing spring 80 of the switching member 50 is inclined so that the position of the first connection portion a is higher than the position of the second connection portion B. Due to this inclination, the oblique reverse spring load P1 by the second connection portion B and the first connection portion a of the reverse spring 80 is converted into the contact load P2 toward the lower side Z1 with respect to the outer spring 70. That is, the outer spring 70 is biased to the lower side Z1 and the front side X1 by the reverse spring load P1, and the movable contact 44 is pressed against the first fixed contact 42 by the contact load P2 directed to the lower side Z1.
From this state, when the pressure (i.e., external force) of the refrigerant introduced into the element 116 via the joint pipe 117 shown in fig. 1 suddenly increases, the sensing member such as a bellows or a diaphragm changes in the front-rear direction X according to the pressure change. Then, the change is transmitted as an actuating force to the link 17 via the transmission member 118. The link 17 receiving the operating force (external force) rotates to one side a around the rotation shaft 16 shown in fig. 3. The rotational movement of the link 17 is transmitted to the working shaft 20 via the receiving portion 18 and the pressed portion 21, and the working shaft 20 is converted into movement toward the lower side Z1, i.e., toward the advancing side. Thus, as indicated by the arrow directed to the lower side Z1 in fig. 5, the working shaft 20 moves to the lower side Z1. When the working shaft 20 moves, the inner spring 60 deforms with the movement.
Specifically, the abutting portion 63 of the inner spring 60 is displaced toward the lower side Z1, and with this displacement, the inner spring 60 is deformed toward the lower side Z1 from the bent portion 52 in the direction in which the portion of the first connecting portion a is located at the lower side Z1 than before the deformation. When the inner spring 60 is deformed, the first and second connection portions a and B approach, thereby deforming the reversing spring 80 in a contracting manner. Accordingly, the first connection portion a generates a force in a backward obliquely upward direction (a direction of the upper side Z2 as directed to the rear side X2) as indicated by an arrow in fig. 5, and the second connection portion B generates a force in an oblique downward direction (a direction of the lower side Z1 as directed to the front side X1) as indicated by an arrow in fig. 5. Then, as the working shaft 20 moves, the reversing spring 80 gradually changes toward the vicinity of the front side X1 with respect to the biasing direction of the outer spring 70. When the state shown in fig. 6 (a) is reached, the inner spring 60 is deflected upward Z2 from the vicinity of the hole portion 90 as compared with the initial state shown in fig. 5. Therefore, the inclination with respect to the front-rear direction X of the reversing spring load P1 is maintained more gradually than in the initial state shown in fig. 5. In addition, as a result, the contact load P2, which is a component of the reverse spring load P1 in the up-down direction Z, is also maintained. Further, as the protruding portion 74 is displaced toward the lower side Z1, the acting spring flexes in such a manner as to curve toward the upper side Z2.
When the working shaft 20 is pushed further toward the lower side Z1 from this state, the balance is lost between the force with which the inner spring 60 stored by the deflection of the inner spring 60 is to return to the original shape, the force with which the reversing spring 80 stored by the deformation of the reversing spring 80 is to return to the original shape, and the force with which the outer spring 70 stored by the deflection of the outer spring 70 is to return to the original shape, and the contact point holding portion 72 of the outer spring 70 generates a first reversing action (reversing action) with which the contact point holding portion 72 jumps down toward the upper side Z2. Thereby, the movable contact 44 is separated from the first fixed contact 42 and contacts the second fixed contact 43, and the conduction destination of the movable contact 44 is switched. In this state, contrary to the initial state, the reversing spring 80 is inclined so that the position of the first connecting portion a is lower than the position of the second connecting portion B, and the direction of biasing the reversing spring 80 against the outer spring 70 is the upper side Z2 and the front side X1. Therefore, the movable contact 44 is pressed against the second fixed contact 43.
On the other hand, when the pressure of the refrigerant introduced into the element 116 through the joint pipe 117 decreases from the state where the movable contact 44 and the second fixed contact 43 are in conduction, the link 17 rotates to the other side b around the rotation shaft 16 shown in fig. 3, and the operation shaft 20 moves to the upper side Z2, i.e., the retreating side. When the working shaft 20 moves to the retreating side, the inner spring 60 deforms toward the upper side Z2 with the bent portion 52 as a starting point so that the portion of the first connecting portion a is positioned at the upper side Z2 as compared with before the deformation. The reversing spring 80 deforms so as to displace the first connecting portion a toward the upper side Z2. The outer spring 70 is deflected to bend toward the lower side Z1. The force of the inner spring 60 to return to the original shape, the force of the reverse spring 80 to return to the original shape, which is accumulated by the deflection of the inner spring 60, and the force of the outer spring 70 to return to the original shape, which is accumulated by the deflection of the protruding portion 74 of the outer spring 70, are unbalanced, and the contact point holding portion 72 of the outer spring 70 generates a second reverse operation (reverse operation) of jumping down to the lower side Z1 at one stroke. Thereby, the movable contact 44 is separated from the second fixed contact 43 and contacts the first fixed contact 42, and the conduction destination of the movable contact 44 is switched.
In the present embodiment, the position at which the reversing operation occurs in the movement range of the working shaft 20 is referred to as a reversing position γ. The reversing position γ includes a first reversing position γ1 at which the working shaft 20 moving toward the lower side Z1 passes and causes a first reversing operation, and a second reversing position, not shown, at which the working shaft 20 moving toward the upper side Z2 passes and causes a second reversing operation. In this structure, after the lower end portion of the working shaft 20 passes through the first reversing position γ1 toward the lower side Z1, the first reversing operation is generated in which the movable contact 44 jumps upward to the upper side Z2. On the other hand, after the lower end portion of the working shaft 20 passes through the second reversing position toward the upper side Z2, a second reversing operation is generated in which the movable contact 44 is moved down toward the lower side Z1.
According to this structure, for example, by mounting the micro switch 1 on the pressure responsive switch 100, it is possible to configure a switch that switches the conduction destination of the movable contact 44 from the first fixed contact 42 to the high voltage of the second fixed contact 43 when an abnormally high voltage occurs. In this case, the microswitch 1 may be configured as a switch in which the first reverse position γ1, which is a setting value for triggering the high-voltage cutoff, and the second reverse position, which is a setting value for triggering the return to the original state, are different from each other. However, this is merely an example, and for example, the first inversion position γ1 and the second inversion position may be set at the same position, and the number of inversion positions γ may be set to one. That is, the switch may be configured such that the first inversion position γ1, which is a setting value for triggering the high-voltage shut-off, and the second inversion position, which is a setting value for triggering the recovery of the original state, are at the same position.
Here, in the switching member 250 of the conventional micro switch 200 shown in fig. 6 (B), the hole portion 90 is not formed in the inner spring 260 as in the present embodiment, and the rigidity of the inner spring 260 is greater than the rigidity of the inner spring 60 in the present embodiment. Therefore, in a state where the lower end portion of the working shaft 20 that moves toward the lower side Z1 is located at the first reversing position γ1, the inner spring 260 extends in the front-rear direction X without flexing. Therefore, the first connection portion a and the second connection portion B of the reversing spring 80 are located at the same position in the up-down direction Z, and the reversing spring load P1 of the reversing spring 80 is not inclined to the front-back direction X. Therefore, the reversing spring load P1 is not converted into the contact load P2 as described above in the direction in which the outer spring 70 extends, and the movable contact 44 is not pressed against the first fixed contact 42 before the first reversing operation. Therefore, when an unexpected external force such as vibration or pressure fluctuation of the refrigerant is applied to the pressure-responsive switch 100, the movable contact 44 is easily displaced in the up-down direction Z, and a chattering phenomenon in which contact and interval are repeated with respect to the first fixed contact 42 or the second fixed contact 43 is easily generated.
In contrast, in the present embodiment, as described above, the hole portion 90 is provided in the inner spring 60, and the rigidity of the inner spring 60 decreases as going from the side where the abutment portion 63 is located toward the front side X1 where the first connection portion a is located. Therefore, as shown in fig. 6 (a), in a state where the lower end portion of the working shaft 20 moving toward the lower side Z1 is located at the first reversing position γ1, the front side X1 portion of the inner spring 60 is deflected to bend toward the upper side Z2 from the portion where the hole portion 90 is formed. In the present embodiment, the state in which the inner spring 60 is deformed by being deflected in this way is referred to as a deformed state. Since the inner spring 60 is in the deformed state, the position of the first connecting portion a is located on the upper side Z2 as compared with the conventional microswitch 200, and the tilt of the reversing spring 80 can be maintained until the first reversing operation is performed, the position of the first connecting portion a being higher than the position of the second connecting portion B.
Therefore, the outer spring 70 is biased toward the lower side Z1 and the front side X1 by the reversing spring load P1, and the movable contact 44 can be maintained in a state of being pressed toward the first fixed contact 42 by the contact load P2 toward the lower side Z1. In the present embodiment, the first connection portion a and the second connection portion B of the reversing spring 80 are located at the same position in the up-down direction Z in the process that the movable contact 44 is away from the first fixed contact 42 (the second fixed contact 43) and faces the second fixed contact 43 (the first fixed contact 42). In this way, the reversing spring 80 generates a biasing force that maintains the state in which the movable contact 44 is pressed against the first fixed contact 42 by the outer spring 70 until the first reversing operation is generated. Therefore, even immediately before the first reversing operation, the movable contact 44 is kept pressed against the first fixed contact 42. Thus, when an unexpected external force such as vibration or pressure fluctuation of the refrigerant is applied to the pressure-responsive switch 100, a chattering phenomenon in which the movable contact 44 repeatedly contacts and separates from the first fixed contact 42 or the second fixed contact 43 is difficult to occur.
In addition, the inner spring 60 is also in a deformed state immediately before the second reversing action occurs. That is, in a state in which the lower end portion of the working shaft 20 that moves toward the upper side Z2 is located at the second reversal position, the inner spring 60 is in a deformed state. This can maintain the inclination of the reversing spring 80 in which the position of the first connecting portion a is lower than the position of the second connecting portion B until the second reversing operation is performed, and maintain the state in which the movable contact 44 is pressed against the second fixed contact 43 until the second reversing operation is performed.
As described above, according to the above embodiment, by providing the hole portion 90 (rigidity reducing member) in the inner spring 60 (the working spring), when the working shaft 20 is located at the first reversing position γ1 (the reversing position), that is, in a state immediately before the first reversing action (reversing action) occurs, the inner spring 60 can be placed in the deformed state. By placing the inner spring 60 in the deformed state, the reversing spring 80 can generate a biasing force that maintains the state in which the outer spring 70 (acting spring) presses the movable contact 44 against the first fixed contact 42 (fixed contact). Therefore, even before the first reversing operation, the state in which the movable contact 44 is pressed against the first fixed contact 42 can be reliably maintained, and even when an unexpected external force such as vibration or pressure fluctuation is generated, the chatter phenomenon or the like can be suppressed. Accordingly, the micro switch 1 capable of stably maintaining the conductive state of the contact 40 can be provided.
Further, according to the present embodiment, by providing the first inversion position γ1 and the second inversion position, the present invention can be applied to a micro switch 1 of a type in which the first inversion position γ1 (inversion position) at which the conduction destination of the movable contact 44 is switched from the first fixed contact 42 to the first inversion operation (inversion operation) of the second fixed contact 43 is different from the second inversion position (inversion position) at which the conduction destination of the movable contact 44 is switched from the second fixed contact 43 to the first fixed contact 42, and the state in which the movable contact 44 is pressed against the fixed contact 41 can be maintained until the inversion operation.
In addition, according to the present embodiment, the hole portion 90 reduces the rigidity of the inner spring 60 toward the side of the first connection portion a (connection portion), and can deform the side of the first connection portion a of the inner spring 60 more easily than the side of the working shaft 20 of the inner spring 60. This makes it possible to maintain the deformed state of the inner spring 60 on the first connecting portion a side more easily. Therefore, immediately before the reversing operation, the biasing force of the outer spring 70 against the reversing spring 80 is more easily maintained, and the state in which the outer spring 70 presses the movable contact 44 against the fixed contact 41 can be stably maintained. In addition, according to this structure, the rigidity of the side of the working shaft 20 in the inner spring 60 is easily increased, and the durability of the side of the working shaft 20 in the inner spring 60 can be improved.
In addition, according to the present embodiment, the rigidity reducing member can be provided in the micro switch 1 by a simple method of the hole portion 90 in the inner spring 60.
In addition, according to the present embodiment, by increasing the size of the hole portion 90 in the left-right direction Y toward the first connecting portion a, the volume of the inner spring 60 can be reduced toward the first connecting portion a side and increased toward the abutting portion 63 side. Therefore, the rigidity of the inner spring 60 can be made to decrease toward the first connecting portion a side, and the side of the first connecting portion a in the inner spring 60 can be made to be more easily deformed than the side of the working shaft 20 in the inner spring 60. This makes it possible to maintain the deformed state of the inner spring 60 on the first connecting portion a side more easily.
Further, according to the present embodiment, the pressure responsive switch 100 can be constructed by mounting the micro switch 1 capable of stably maintaining the on state of the contact 40.
Next, a modification of the micro switch 1 will be described. Fig. 7 is a plan view showing a part of the switching member 50' in the modification. In the modification, the difference from the above embodiment is that the hole portion 90 is not formed in the narrow portion 64. The narrow portion 64 has cut portions 91 formed at both edges in the left-right direction Y (width direction) of the narrow portion 64. The notch 91 has a tapered shape inclined so as to be positioned inward in the left-right direction Y as going toward the rear side X2, and by forming the notch 91, the width dimension of the narrow portion 64 in the left-right direction Y decreases as going toward the rear side X2. With this configuration, the rigidity of the inner spring 60 is lowered particularly at the portion of the front side X1 compared with the wide portion 61. That is, the cutout 91 constitutes a rigidity reducing member in the modification. According to such a modification, the same operational effects as those of the above embodiment can be obtained. In addition, according to this structure, the rigidity reducing member is provided in the micro switch 1 by a simple method of forming the cutout 91 by cutting the inner spring 60.
Further, the above embodiments merely illustrate typical modes of the invention, and the invention is not limited thereto. That is, the present invention can be variously modified and implemented within a range not departing from the gist of the present invention. In these modifications, it is needless to say that the configuration of the microswitch 1 of the present invention is also within the scope of the present invention. For example, in the description of the present embodiment, although the micro switch 1 is described as being used for detecting an abnormally high voltage, the micro switch 1 may be used when detecting an abnormally low voltage in contrast thereto. In the initial state, the link 17 is inclined so as to be located on the upper side Z2 from the rear end portion supported by the rotation shaft 16 toward the front end portion, but conversely, the microswitch 1 may be constructed by setting the rotated state of the link 17 to the initial state, setting the other side b of the present embodiment to the one side a, and adjusting the operation direction of the operation shaft 20 and the switching member 50 accordingly.
In addition to the pressure switch, the microswitch 1 may be mounted on various switches in which the link 17 is rotated by some external force. For example, although the use as a pressure switch is mainly described in the pressure-responsive switch 100 of the present embodiment, the pressure-responsive switch 100 may be used as a temperature switch. That is, in the present embodiment, the use of the pressure switch that introduces the fluid to be detected (here, the refrigerant circulating in the refrigerating cycle) through the joint pipe 117 and detects the pressure change by directly applying the pressure of the object to be detected to the sensing member such as the bellows or the diaphragm is described as an example, but the use of the pressure responsive switch 100 is not limited to this.
That is, the temperature sensing tube may be connected to the element 116 in the pressure responsive switch 100 of the present embodiment via a capillary tube, and the temperature switch may be configured by filling the inside of the closed space formed by the sensing member, the capillary tube, and the temperature sensing tube with a refrigerant. As described above, in the temperature switch using the pressure-responsive switch 100 of the present embodiment, the sensing member deforms or displaces in the front-rear direction X in accordance with the pressure inside the closed space that changes based on the temperature change detected by the temperature sensing tube, and the on state of the contact 40 is changed by transmitting the force at this time to the link 17. In the present embodiment, the microswitch 1 is provided with the pair of links 17, the corresponding operating shaft 20, the contact 40, the switching member 50, and the like, and the present invention is not limited to the double microswitch 1, but is applicable to various microswitches, although the so-called double microswitch 1 is configured.
In the present embodiment, the plate-shaped inner spring 60 is used as the working spring, and the plate-shaped outer spring 70 is used as the working spring. But the structure of the working spring or the acting spring is not limited thereto. For example, the working spring or the action spring may be constituted by a spring member or the like which is not formed in a plate shape.