Micro switch and switch device

Abstract

The purpose of the present invention is to provide a micro switch and a switch device which inhibits positional deviation of the operation shaft while keeping smooth operation performance of an operation shaft.　A micro switch (1) comprises: a micro-operation shaft (30) which causes force to act in the axial direction (Z) on a switching means (40) for switching a conduction destination of a contact point (50); an operation part (20) which causes the micro-operation shaft (30) to move forward and backward in the axial direction (Z); and a rotation shaft (23) which rotatably supports the operation part (20). The micro-operation shaft (30) is provided with an abutting part (31) which abuts against the operation part (20). The operation part (20) is provided with a shaft support part (26) which supports the abutting part (31). At least one of the abutting part (31) and the shaft support part (26) is provided with a first curved surface section (a1) or a second curved surface section (a2) which comes into sliding contact with the other of the abutting part (31) and the shaft support part (26) in response to the rotation of the operation part (20).

Description

Microswitches and switch devices

[0001] The present invention relates to a microswitch and a switch device.

[0002] Conventionally, devices incorporating a microswitch have been known (see, for example, Patent Document 1). The thermostat described in Patent Document 1 includes a microswitch having a switch box that houses a contact mechanism, an operating shaft that reaches the switch box, and an L-shaped operating plate that moves the operating shaft back and forth in the axial direction. The L-shaped operating plate has a horizontal side portion extending horizontally, a vertical side portion extending vertically, and a rotation fulcrum provided on the underside of the horizontal side portion, and the operating shaft is inserted through the vertical side portion of the L-shaped operating plate in the plate thickness direction. When the L-shaped operating plate rotates around the rotation fulcrum, the operating shaft moves back and forth in the axial direction in response to the rotation, thereby opening and closing the contact mechanism.

[0003] Special Publication No. 05-042090

[0004] In a thermostat configuration like the one described above, the rotational motion of the L-shaped actuating plate must be converted into axial movement of the actuating shaft. To ensure this conversion, a certain clearance must be provided between the actuating shaft and the portion of the L-shaped actuating plate through which the actuating shaft passes. However, if vibration or impact is applied to the actuating shaft or the L-shaped actuating plate, the position of the actuating shaft changes within the clearance, which can change the amount of axial displacement of the actuating shaft and prevent the contact mechanism from opening and closing properly. On the other hand, if this clearance is eliminated, it becomes difficult for the actuating shaft to follow the rotational motion of the L-shaped actuating plate, making it difficult to move the actuating shaft back and forth.

[0005] An object of the present invention is to provide a microswitch and a switch device that suppresses positional deviation of an operating shaft while maintaining smooth operability of the operating shaft.

[0006] In order to solve the above problems and achieve the object, the microswitch of the present invention comprises an operating shaft that applies a force in an axial direction to a switching means that switches the destination of the contacts, an operating part that moves the operating shaft back and forth in the axial direction, and a fulcrum part that rotatably supports the operating part, and is characterized in that an abutment part that abuts against the operating part is provided on one end side of the axial direction of the operating shaft, and the operating part is provided with a shaft support part that supports the abutment part, and at least one of the abutment part and the shaft support part is provided with a curved part that slides against the other of the abutment part and the shaft support part as the operating part rotates.

[0007] According to the present invention, the curved surface portion provided on at least one of the abutment portion of the actuating shaft and the shaft support portion of the actuating unit is always in contact with the other of the abutment portion and the shaft support portion. This contact makes it possible to suppress displacement of the actuating shaft even when vibrations, shocks, etc. are applied to the actuating shaft or the actuating unit. Furthermore, with this configuration, the actuating shaft can be suitably moved forward and backward in response to the rotational movement of the actuating unit through sliding contact between the curved surface portion and the abutment portion or the shaft support portion, eliminating the need for a clearance as required by the conventional microswitches described above. Therefore, it is possible to provide a microswitch that suppresses displacement of the actuating shaft while maintaining smooth operability of the actuating shaft.

[0008] In this case, it is preferable that the curved surface portion is provided on both the contact portion and the shaft support portion, the curved surface portion of the contact portion is formed in a hemispherical shape, the curved surface portion of the shaft support portion is formed in a conical shape, and the curved surface portions are in annular contact with each other around the axis of the operating shaft. With this configuration, the area of ​​line contact between the contact portion and the shaft support portion can be increased on the circumference around the axis of the operating shaft, thereby making it possible to suitably suppress positional deviation of the operating shaft.

[0009] In this case, the curved surface portion may be formed in an arc shape when viewed from the axial direction of the rotation shaft of the actuating unit, and the curved surface portion may be provided on the abutment portion so that the arc extends along the axial direction of the rotation shaft of the actuating unit, and the shaft support portion may have a pair of inclined surfaces that contact the abutment portion, and the curved surface portion may be in line contact with each of the pair of inclined surfaces to form a plurality of contact portions that are independent of each other. With this configuration, the curved surface portion provided on the abutment portion may be in line contact with the inclined surfaces of the shaft support portion at a plurality of locations, thereby preferably suppressing positional deviation of the actuating shaft.

[0010] The shaft support portion may be configured with a V-shaped groove in a cross section perpendicular to the rotation axis of the actuating portion. With this configuration, the groove is configured with a relatively simple V-shape, and the curved surface of the contact portion is brought into line contact with the groove at multiple points, thereby suitably suppressing positional deviation of the actuating shaft.

[0011] Preferably, the curved surface portion is formed in an arc shape when viewed from the axial direction of the rotation shaft of the actuating unit and is provided on the shaft support portion, and the abutment portion has a first corner portion and a second corner portion that abut on the curved surface portion and is formed in a rectangular shape when viewed in a cross section perpendicular to the rotation shaft of the actuating unit. With this configuration, the curved surface portion is provided on the shaft support portion, and positional deviation of the actuating shaft can be suitably suppressed.

[0012] The switch device of the present invention is characterized by being equipped with any of the microswitches described above. With this configuration, the switch device can be configured using a microswitch that suppresses positional deviation of the operating shaft while maintaining smooth operability of the operating shaft. Examples of the switch device include a pressure switch that detects the pressure of a refrigerant in a refrigeration cycle and a temperature switch that detects the temperature of the refrigerant.

[0013] According to the present invention, it is possible to provide a microswitch and a switch device that suppresses positional deviation of an operating shaft while maintaining smooth operability of the operating shaft.

[0014] 9 is a perspective view of a microswitch according to one embodiment of the present invention. A cross-sectional view taken along the line A-A in FIG. 1. An enlarged cross-sectional view of a lever and a micro-actuating shaft that constitute part of the microswitch. An enlarged view of the main parts of the lever and the micro-actuating shaft. A rear view of the lever. A cross-sectional view taken along the line B-B in FIG. 5. (A) is an enlarged cross-sectional view of a lever and a micro-actuating shaft according to a second embodiment, and (B) is an enlarged cross-sectional view of a groove portion of an actuating portion according to the second embodiment. An enlarged view of the main parts of the lever and the micro-actuating shaft according to the second embodiment. A rear view of the lever according to the second embodiment. A cross-sectional view taken along the line CC in FIG. 9. (A) is an enlarged cross-sectional view of a lever and a micro-actuating shaft according to a third embodiment, and (B) is an enlarged view of the main parts of a lever and a micro-actuating shaft according to a modified example of the third embodiment.

[0015] An embodiment of the present invention will be described below with reference to Figures 1 to 6. A microswitch 1 according to this embodiment is mounted in a switching device, such as a pressure switch that detects the pressure of a refrigerant in a compressor of a refrigeration cycle or a temperature switch that detects the temperature of the refrigerant, and constitutes part of the switching device. The microswitch 1 includes a box-shaped case 10, an actuating unit 20 provided on the top of the case 10, a micro actuating shaft 30 (actuating shaft) that is moved axially back and forth by the actuating unit 20, a switching means 40 to which a force acts when the micro actuating shaft 30 is displaced in the axial direction, and a contact 50 whose electrical connection is switched by the switching means 40.

[0016] In the following description, arrows X, Y, and Z in the drawings represent directions perpendicular to one another. The movement direction of the micro-actuation shaft 30, which will be described later, is indicated by arrow Z and will be referred to as the "axial direction Z." One side of the axial direction Z will be referred to as the "upper side Z1," and the other side will be referred to as the "lower side Z2." The horizontal directions are indicated by arrows X and Y and will be referred to as the "front-rear direction X" and the "width direction Y," respectively. One side of the front-rear direction X will be referred to as the "front side X1," and the other side will be referred to as the "rear side X2." This is merely for the convenience of explanation, and does not necessarily coincide with the directions in the actual usage state of the microswitch 1, and does not limit the directions in the actual usage state of the microswitch 1.

[0017] The case 10 includes a substantially rectangular box-shaped box portion 11 and a lid portion 12 provided on an upper side Z1 of the box portion 11. As shown in FIG. 2 , the box portion 11 includes an internal storage space 13. Components such as the switching means 40 and contacts 50 are housed in the storage space 13. A protrusion 14 protruding toward the rear side X2 is formed on the rear side X2 of the side walls of the box portion 11. The protrusion 14 serves to secure the box portion 11 to a device (e.g., a device such as the pressure switch described above) in which the microswitch 1 is mounted, and together with a base portion 15 described below, constitutes a connecting portion that connects the box portion 11 to the device. The lid portion 12 includes a base portion 15 disposed above the protrusion 14 and extending toward the upper side Z1, and a lid main body 16 that is continuous with the base portion 15 and extends perpendicular to the base portion 15 in the front-rear direction X. The base portion 15 is formed in the shape of a thick plate, and together with the above-mentioned protruding portion 14 constitutes a connecting portion of the joint pipe.

[0018] On the surface of the base portion 15 facing the front side X1, a total of two pairs of protrusions 15a are formed side by side in the width direction Y, each protruding toward the front side X1 and spaced apart in the width direction Y. A rectangular parallelepiped pedestal 17 is formed between the pair of protrusions 15a, protruding toward the front side X1 from the surface of the base portion 15 facing the front side X1. A fixing portion 18 for fixing a lever 22 (described later) is fixed to the pedestal 17 by a fastening member 19. The fixing portion 18 is formed by bending a metal plate, etc., and covers the upper side Z1 surface and both side surfaces in the width direction Y of the pedestal 17, and protrudes toward the front side X1 beyond the end of the front side X1 of the pedestal 17. The lid main body 16 is formed in the shape of a rectangular plate extending in the front-rear direction X and the width direction Y, and has an insertion hole 16a penetrating in the axial direction Z at its center.

[0019] The actuating unit 20 is a part that moves the micro actuating shaft 30 back and forth in the axial direction Z by being displaced in response to an external force. An example of the external force is a force generated and transmitted when a bellows, serving as a sensitive member, is displaced in response to changes in the pressure or temperature of the refrigerant when the microswitch 1 is used as the pressure switch that detects the pressure or temperature of the refrigerant described above. In this case, the actuating unit 20 functions as a displacement transmission member that transmits the displacement of the bellows or the like to the micro actuating shaft 30. As shown in FIG. 3 , the actuating unit 20 includes a support unit 21, a lever 22 serving as an actuating metal fitting and disposed on the front side X1 of the support unit 21, and a rotating shaft 23 (fulcrum) that connects the support unit 21 and the lever 22. The support unit 21 is fixed to the case 10 and supports the lever 22. The lever 22 is rotatable about the rotating shaft 23 (counterclockwise in this embodiment, as viewed from the direction shown in FIG. 3 ) in response to the external force, with the rotating shaft 23 as a fulcrum.

[0020] As shown in Figures 5 and 6, the lever 22 includes a flat pressure plate 24 extending in the width direction Y and the front-rear direction X, and sidewalls 25 rising from both edges of the pressure plate 24 in the width direction Y toward the lower side Z2. A shaft support 26 is formed in a central rear side X2 portion of the pressure plate 24, opening toward the lower side Z2 and projecting conically toward the upper side Z1. The inner surface of the shaft support 26 is conically recessed and forms a first curved surface a1 (curved surface portion) that slides against a contact portion 31 (described later) of the micro-actuation shaft 30. That is, the first curved surface a1 of the shaft support 26 is formed conically and supports the micro-actuation shaft 30 via the contact portion. The end of the rear side X2 of the sidewalls 25 projects toward the rear side X2 from the end of the pressure plate 24 in the width direction Y, and this projecting portion forms an insertion portion 27 through which the rotation shaft 23 is inserted in the width direction Y. The rotation shaft 23 is a shaft that rotatably supports the lever 22. The rotation shaft 23 penetrates both side walls in the width direction Y of the fixed part 18 fixed to the base 17, and also penetrates the end of the front side X1 of the support part 21 and the insertion part 27 of the lever 22 in the width direction Y, and is fixed to the fixed part 18.

[0021] The micro-actuation shaft 30 is a shaft member that moves back and forth in the axial direction Z in response to the rotational movement of the lever 22 in the actuation unit 20. It is inserted through the insertion hole 16a of the lid body 16, extends in the axial direction Z, and is fixed to the case 10 so as to be displaceable in the axial direction Z. As shown in FIG. 2 , the micro-actuation shaft 30 includes an abutment portion 31 formed at an end (one end) on the upper side Z1 located outside the case 10, and an engagement portion 32 constituting an end on the lower side Z2 located inside the case 10. As shown in FIGS. 3 and 4 , the abutment portion 31 abuts against the shaft support portion 26 of the lever 22, and its outer surface forms a hemispherical second curved surface portion a2. The second curved surface portion a2 is capable of making annular contact with the first curved surface portion a1 around the axis of the micro-actuation shaft 30 as the lever 22 rotates.

[0022] That is, curved surface portions (first curved surface portion a1 and second curved surface portion a2) are provided on both the abutment portion 31 and the shaft support portion 26, and the curved surface portions are in annular contact with each other around the axis of the micro-actuation shaft 30. In other words, at least one of the abutment portion 31 and the shaft support portion 26 is provided with a curved surface portion that slides against the other of the abutment portion 31 and the shaft support portion 26 as the lever 22 rotates. The engagement portion 32 is a portion that engages with the switching means 40, and by engaging this engagement portion 32 with the switching means 40, a force is applied to the switching means 40 in the axial direction Z when the micro-actuation shaft 30 moves forward or backward.

[0023] As shown in FIG. 2 , the switching means 40 includes a movable piece 41 that engages with the engaging portion 32 of the micro-actuation shaft 30, a snap piece 42 that abuts against the tip of the movable piece 41 and biases a movable contact 53 (described later) toward a first fixed contact 51 or a second fixed contact 52, and a conductive piece 43 that includes the movable contact 53 at its end on the front side X1. The contacts 50 are conductive members that are respectively connected to a plurality of terminals (not shown) provided on the case 10, and include a first fixed contact 51, a second fixed contact 52, and the movable contact 53 fixed to the end on the front side X1 of the conductive piece 43. The first fixed contact 51 is fixed to the case 10 within the housing space 13 of the case 10 and connected to a first terminal (not shown). The second fixed contact 52 is located above the first fixed contact 51 (Z1) and is fixed to the case 10 within the housing space 13, facing the first fixed contact 51 in the axial direction Z. The second fixed contact 52 is connected to the first terminal (not shown). The movable contact 53 is disposed between the first fixed contact 51 and the second fixed contact 52, and is electrically conductive when it comes into contact with the first fixed contact 51 and the second fixed contact 52, respectively.

[0024] The operation of the microswitch 1 will now be described. Here, the microswitch 1 is mounted on the pressure switch described above, which detects the refrigerant pressure. The microswitch 1 switches the contact 50 between a low-pressure state where the refrigerant pressure is low and a high-pressure state where the refrigerant pressure is higher by a predetermined amount. FIG. 2 shows the microswitch 1 when the refrigerant pressure is in the low-pressure state. In this state, the actuating member 20 does not press the micro actuating shaft 30 downward Z2. The movable contact 53, biased downward Z2 by the snap piece 42, abuts the first fixed contact 51, establishing electrical conduction, thereby detecting the low-pressure state. Next, when the refrigerant pressure increases, pressure acts on the bellows of the pressure switch, displacing the bellows. This displacement is transmitted to the actuating member 20 via a transmission member (not shown), applying an external force to the actuating member 20 toward the lower Z2. As a result, the lever 22 of the actuating member 20 rotates counterclockwise around the rotation shaft 23, as shown in FIG. 3. At this time, as the lever 22 rotates, the first curved surface portion a1 of the shaft support portion 26 slides against the second curved surface portion a2 of the abutment portion 31 of the micro actuation shaft 30, transmitting the rotational force of the lever 22 to the micro actuation shaft 30.

[0025] Next, due to the sliding contact, the micro-actuating shaft 30 is displaced downward Z2 in response to the rotation of the lever 22. As the micro-actuating shaft 30 is displaced downward Z2, a pressing force toward the downward Z2 acts on the switching means 40, deforming the movable piece 41. The deformation of the movable piece 41 causes the snap piece 42 to deform in conjunction with the deformation of the movable piece 41. When the deformation of the snap piece 42 exceeds a certain amount, the biasing force on the conductive piece 43 is reversed, and the conductive piece 43 is biased upward Z1. This releases the conductive state between the movable contact 53 and the first fixed contact 51, and the movable contact 53 and the second fixed contact 52 come into contact and establish electrical continuity. In other words, the switching means 40 switches the conductive destination of the contact 50. This detects that the microswitch 1 has switched from a low-voltage state to a high-voltage state.

[0026] While Fig. 2 illustrates the microswitch 1 when the refrigerant is in a low-pressure state in this embodiment, Fig. 2 may also illustrate the microswitch 1 when the refrigerant is in a high-pressure state. That is, the high-pressure state may be detected in the state illustrated in Fig. 2. When the refrigerant pressure drops from this state, the bellows is displaced, the displacement is transmitted to the actuation portion 20, the micro-actuation shaft 30 is displaced downward Z2, the biasing force of the snap piece 42 is reversed, the conductive state between the movable contact 53 and the first fixed contact 51 is released, and the conductive state between the movable contact 53 and the second fixed contact 52 is established, and it may be detected that the microswitch 1 has switched from the high-pressure state to the low-pressure state.

[0027] In this embodiment, the operation of the microswitch 1 has been described as being mounted in a pressure switch that detects the pressure of a refrigerant. However, this is merely an example. For example, the operation of the microswitch 1 may be similarly achieved when mounted in a temperature switch that detects the temperature of a refrigerant, switching the electrical connection of the contact 50 between a low-temperature state where the refrigerant temperature is low and a high-temperature state where the refrigerant temperature is higher by a predetermined amount. In this case, the state shown in FIG. 2 is assumed to be a low-temperature state. As the refrigerant temperature rises, the bellows expands and displaces. This displacement is transmitted to the actuating element 20 via a transmission member (not shown), applying an external force toward the lower side Z2 to the actuating element 20. As a result, the micro-actuating shaft 30 is displaced downward Z2, as in the case of a pressure switch. The load generated by this displacement acts on the switching means 40, reversing the biasing force of the snap piece 42. This releases the electrical connection between the movable contact 53 and the first fixed contact 51, and establishes electrical connection between the movable contact 53 and the second fixed contact 52. This allows detection of the microswitch 1 switching from the low temperature state to the high temperature state.

[0028] As described above, according to the embodiment described above, the curved surface portions (first curved surface portion a1, second curved surface portion a2) provided on at least one of the abutment portion 31 of the micro actuation shaft 30 and the shaft support portion 26 of the actuation unit 20 are constantly in contact with the other of the abutment portion 31 and the shaft support portion 26. This contact can prevent the micro actuation shaft 30 from shifting in position even when vibrations, shocks, or the like are applied to the micro actuation shaft 30 or the actuation unit 20. Furthermore, according to this configuration, the sliding contact between the first curved surface portion a1 and the second curved surface portion a2 allows the micro actuation shaft 30 to suitably move forward and backward in response to the rotational movement of the actuation unit 20, eliminating the need for a clearance as provided in the conventional microswitch described above. Therefore, it is possible to provide a microswitch 1 that prevents the micro actuation shaft 30 from shifting in position while maintaining smooth operability of the micro actuation shaft 30. Furthermore, according to this embodiment, since curved surfaces are provided on both the contact portion 31 and the shaft support portion 26, the area of ​​line contact between the contact portion 31 and the shaft support portion 26 can be increased on the circumference around the axis of the actuation shaft, thereby making it possible to suitably suppress misalignment of the micro actuation shaft 30. Furthermore, according to the above-described embodiment and modified examples, a switch device such as a pressure switch or a temperature switch can be configured using the microswitch 1 that suppresses misalignment of the micro actuation shaft 30 while maintaining smooth operability of the micro actuation shaft 30.

[0029] Next, a second embodiment of the present invention will be described. Fig. 7(A) is an enlarged cross-sectional view of the lever 22 and the micro-actuating shaft 30 according to the second embodiment, and Fig. 7(B) is an enlarged cross-sectional view of the groove 28 of the actuator 20 according to the second embodiment. Fig. 8 is an enlarged view of the main parts of the lever 22 and the micro-actuating shaft 30 according to the second embodiment. Fig. 9 is a rear view of the lever 22 according to the second embodiment, and Fig. 10 is a cross-sectional view taken along the line CC in Fig. 9. As shown in Fig. 9, in the second embodiment, a through-hole 24a is formed in the pressing plate 24 of the actuator 20. On both sides of the through-hole 24a in the width direction Y, shaft support portions 260 are formed, protruding upward Z1. As shown in Figure 7(B) , the inner surface of the shaft support portion 260 forms a V-shaped groove portion 28 in a cross section perpendicular to the rotating shaft 23, which is composed of a first inclined surface 28a (shown only in Figure 7(B) ) that is positioned on the lower side Z2 as it approaches the front side X1, and a second inclined surface 28b (shown only in Figure 7(B) ) that is positioned on the lower side Z2 as it approaches the rear side X2.

[0030] As shown in FIG. 10 , the micro-actuation shaft 30 is formed in a plate shape extending in the width direction Y and the axial direction Z. An insertion protrusion 33 that protrudes toward the upper side Z1 is formed at the end of the upper side Z1 of the micro-actuation shaft 30. The insertion protrusion 33 is a protrusion that is inserted into the through-hole 24a of the pressing plate portion 24, and as shown in FIG. 9 , is composed of a first insertion protrusion 33a that is rectangular in rear view and a second insertion protrusion 33b that is arranged on the front side X1 of the first insertion protrusion 33a and has a smaller dimension in the width direction Y than the first insertion protrusion 33a. The different dimensions in the width direction Y between the first insertion protrusion 33a and the second insertion protrusion 33b prevent the orientation of the micro-actuation shaft 30 in the front-rear direction X from being reversed when attaching the micro-actuation shaft 30.

[0031] Abutment portions 310 that abut against the groove portion 28 are formed on both sides of the insertion protrusion 33 in the width direction Y. The abutment portions 310 form third curved surface portions a3 (curved surface portions) whose outer surfaces are formed in an arc shape in side view (as viewed from the axial direction of the rotation shaft 23). The third curved surface portions a3 are in contact with the first inclined surfaces 28a and the second inclined surfaces 28b of the groove portion 28. The third curved surface portions a3 are in contact with the first inclined surfaces 28a on both sides of the through hole 24a in the width direction Y and with the second inclined surfaces 28b on both sides of the through hole 24a in the width direction Y, forming a total of four lines of contact portions. In this way, the third curved surface portion a3 (curved surface portion) is formed in an arc shape and is provided on the abutment portion 310, and the shaft support portion 260 has a pair of inclined surfaces (first inclined surface 28a, second inclined surface 28b) that contact the abutment portion 310, and the third curved surface portion a3 makes line contact with each of the pair of inclined surfaces, thereby forming multiple contact portions that are independent of each other.

[0032] In the second embodiment, the microswitch 1 operates in the same manner as in the first embodiment. That is, when the pressure or temperature of the refrigerant changes, pressure acts on the bellows of the pressure switch, displacing the bellows. This displacement is transmitted to the actuating unit 20 via a transmission member (not shown), applying an external force toward the lower side Z2 to the actuating unit 20, causing the lever 22 to rotate around the axis of the rotation shaft 23. When the lever 22 rotates, the third curved surface a3 of the micro actuating shaft 30 slides against the groove 28 of the shaft support 260, transmitting the rotational force of the lever 22 to the micro actuating shaft 30. With this configuration, the third curved surface a3 provided on the abutment portion 310 can be brought into line contact with the inclined surface of the shaft support 260 at multiple locations, thereby effectively suppressing positional deviation of the micro actuating shaft 30. In this embodiment, the portion that comes into sliding contact with the third curved surface portion a3 is configured as the groove portion 28 having a simple V-shaped cross section, but this is merely an example, and the shape of the sliding contact portion can be adjusted as appropriate. For example, a flat surface or an arcuate surface extending in the front-rear direction X may be added as a connecting surface between the pair of inclined surfaces (first inclined surface 28a, second inclined surface 28b) described above. Furthermore, the shaft support portion 260 may be formed by adding, as connecting surfaces, a plurality of inclined surfaces having inclination angles different from those of the first inclined surface 28a and the second inclined surface 28b between the first inclined surface 28a and the second inclined surface 28b.

[0033] Next, a third embodiment of the present invention will be described. FIG. 11(A) is an enlarged view of a main portion of a lever 22 and a micro-actuation shaft 30 according to the third embodiment. In the third embodiment, as shown in FIG. 11(A), a shaft support portion 261 that protrudes toward the upper side Z1 is formed on the pressure plate portion 24 of the lever 22. The inner surface of the shaft support portion 261 forms a fourth curved surface portion a4 that is recessed in an arc shape in a cross section perpendicular to the rotation shaft 23. The end portion of the micro-actuation shaft 30 on the upper side Z1 forms an abutment portion 311 that slides against the fourth curved surface portion a4. The abutment portion 311 is rectangular in the cross section perpendicular to the rotation shaft 23 shown in FIG. 11(A). The abutment portion 311 has a first corner portion 34 and a second corner portion 35 that abut against the fourth curved surface portion a4. That is, the abutment portion 311 contacts the fourth curved surface portion a4 along two lines via the first corner portion 34 and the second corner portion 35. In the third embodiment, the microswitch 1 operates in the same manner as in the first and second embodiments. When the lever 22 rotates around the axis of the rotation shaft 23, the first corner 34 and the second corner 35 of the abutment portion 311 of the micro actuation shaft 30 come into sliding contact with the fourth curved surface a4 of the shaft support portion 261, and the rotational force of the lever 22 is transmitted to the micro actuation shaft 30.

[0034] Next, a modified example of the third embodiment will be described. FIG. 11B is an enlarged view of a main portion of the lever 22 and the micro-actuating shaft 30 according to the modified example of the third embodiment. As shown in FIG. 11B, in the modified example of the third embodiment, the pressure plate 24 of the lever 22 has a through-hole 24a similar to that of the second embodiment. On both sides of the through-hole 24a in the width direction Y, shaft support portions 262 protruding upward Z1 are formed. The inner surface of the shaft support portion 262 forms a fifth curved surface a5 that is recessed in a semicircular shape in a cross section perpendicular to the rotation shaft 23. The abutment portion 311 of the micro-actuating shaft 30 contacts the fifth curved surface a5 at the first corner 34 and the second corner 35 on both sides of the through-hole 24a in the width direction Y, resulting in contact at a total of four lines. In the modified example of the third embodiment, the microswitch 1 operates in the same manner as in the first, second, and third embodiments. When the lever 22 rotates around the axis of the rotation shaft 23, the abutment portion 311 of the micro actuation shaft 30 comes into contact with the fifth curved surface portion a5 of the shaft support portion 262 at two or more lines, and the rotational force of the lever 22 is transmitted to the micro actuation shaft 30. According to the third embodiment and the modified example of the third embodiment, curved surfaces (fourth curved surface portion a4, fifth curved surface portion a5) are formed on the shaft support portions 261, 262 side, and positional deviation of the micro actuation shaft 30 can be suitably suppressed.

[0035] The above-described embodiment merely illustrates a typical embodiment of the present invention, and the present invention is not limited thereto. In other words, various modifications can be made without departing from the gist of the present invention. As long as such modifications still include the configuration of the microswitch 1 of the present invention, they are of course included within the scope of the present invention. For example, in the above-described embodiment and modified example, the curved surface portion on the micro-actuation shaft 30 side is formed in a convex shape toward the shaft support portion 26 side. However, the curved surface portion on the micro-actuation shaft 30 side may be formed in a concave shape toward the shaft support portion 26 side, and the shaft support portion 26 side may be formed in a convex shape. Similarly, the curved surface portion on the shaft support portion 26 side may be formed in a convex shape toward the micro-actuation shaft 30 side. In this case, a groove having the above-described pair of inclined surfaces (first inclined surface 28a, second inclined surface 28b) may be formed on the micro-actuation shaft 30 side. That is, at least one of the contact portion 31 and the shaft support portion 26 may have a curved surface portion that slides against the other of the contact portion 31 and the shaft support portion 26 as the operating portion 20 rotates.

[0036] a1 First curved surface portion (curved surface portion) Z Axis direction 1 Microswitch 20 Actuation portion 23 Rotation axis (fulcrum portion) 26 Shaft support portion 30 Micro actuation axis (actuation axis) 31 Contact portion 40 Switching means 50 Contact point

Claims

1. A microswitch comprising: an operating shaft that applies force in the axial direction to a switching means that switches the electrical connection of a contact; an operating section that moves the operating shaft back and forth in the axial direction; and a fulcrum section that rotatably supports the operating section, wherein one end of the operating shaft in the axial direction is provided with an abutment section that abuts against the operating section, the operating section is provided with a shaft support section that supports the abutment section, and at least one of the abutment section and the shaft support section is provided with a curved surface section that slides against the other of the abutment section and the shaft support section as the operating section rotates.

2. The microswitch described in claim 1, characterized in that the curved surface portion is provided on both the abutment portion and the shaft support portion, the curved surface portion of the abutment portion is formed in a hemispherical shape, the curved surface portion of the shaft support portion is formed in a conical shape, and the curved surface portions contact each other in a ring shape around the axis of the operating shaft.

3. The microswitch described in claim 1, characterized in that the curved surface portion is formed in an arc shape when viewed from the axial direction of the rotation shaft of the actuation part, and the arc is provided on the abutment part so that it extends along the axial direction of the rotation shaft of the actuation part, the shaft support part has a pair of inclined surfaces that contact the abutment part, and the curved surface portion makes line contact with each of the pair of inclined surfaces, thereby forming a plurality of contact parts that are independent of each other.

4. The microswitch according to claim 3, wherein the shaft support portion is configured as a V-shaped groove when viewed in cross section perpendicular to the rotation axis of the actuation portion.

5. A microswitch as described in claim 1, characterized in that the curved surface portion is formed in an arc shape when viewed from the axial direction of the rotation axis of the actuation part and is provided on the shaft support part, and the abutment portion has a first corner portion and a second corner portion that abut on the curved surface portion and is formed in a rectangular shape when viewed in cross section perpendicular to the rotation axis of the actuation part.

6. A switch device equipped with the microswitch according to any one of claims 1 to 5.

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