Manual return type thermal protector

Abstract

A manual return type thermal protector 1 includes: a pair of lead terminals 30 which are arranged in a state in which end parts thereof are separated from each other, and which constitute a part of an electric circuit; a moving-side case 20 that is movable with respect to the pair of lead terminals 30; a connection terminal 40 disposed between the pair of lead terminals 30 and the moving-side case 20; a coil spring 50 that exerts a biasing force on the connection terminal 40 so as to separate the connection terminal 40 from the pair of lead terminals 30; a heat-responsive member 60 in which heat at or above a prescribed temperature causes deformation in a direction that intersects the direction of movement of the moving-side case 20; and an engagement member 70 that holds the moving-side case 20 so that the connection terminal 40 is pressed against the pair of lead terminals 30 in opposition to the biasing force of the coil spring 50, and engages the moving-side case 20 at a plurality of positions such that the hold on the moving-side case 20 is released due to the deformation of the heat-responsive member 60.

Description

Manual reset thermal protector

[0001] The present invention relates to a manual reset thermal protector that interrupts an electric circuit in response to heat generation and can be manually reset after the electric circuit is interrupted.

[0002] Thermal protectors for preventing burnout of electrical equipment and the like due to overheating and overcurrent are known. As such a thermal protector, for example, in Patent Document 1, in a container having a locked portion on the inner surface, a fixed electrode, a movable electrode, a plunger for separating and contacting the movable electrode with respect to the fixed electrode, an elastic body disposed in the axial direction of the plunger, and an elastic plate supported by the plunger and having a locking portion locked to the locked portion of the container at one end, and a thermal response element for separating the locking portion of the elastic plate from the locked portion of the container by a bending and reversing operation are disclosed.

[0003] In the thermal protector disclosed in Patent Document 1, as the locking portion of the elastic plate detaches from the locked portion of the container, the plunger is moved in the axial direction by the stretching action of the elastic body, thereby releasing the contact state between the fixed electrode and the movable electrode and separating the fixed electrode and the movable electrode, and maintaining this separated state.

[0004] With the above-described configuration, due to the bending and reversing operation of the thermal response element accompanying the temperature rise of the device, the elastic plate is pushed down, and the locking portion of the elastic plate detaches from the locked portion of the container. At this time, the plunger moves due to the elongation of the elastic body, releasing the contact state between the fixed electrode and the movable electrode and separating them, thereby interrupting the circuit. Next, after removing the abnormal state of the device, if the reset button is pushed back to the position where the locking portion of the elastic plate and the locked portion are locked, the contact between the fixed electrode and the movable electrode closes again and power supply becomes possible.

[0005] Japanese Patent Application Laid-Open No. 2000-294099

[0006] By the way, in the configuration disclosed in Patent Document 1, the thermal protector has one set of the elastic plate and the thermally responsive element. In this case, the plunger is supported at one point relative to the locking portion of the container by one set of the elastic plate and the thermally responsive element, so there is a possibility that the plunger cannot be stably supported. If the plunger cannot be stably supported, the thermal protector may malfunction.

[0007] In response to this, there is a need for a manual reset type thermal protector that can operate more reliably by engaging an engaging member, which engages with a movable body that presses a connection terminal against a lead terminal and releases engagement with the movable body by deformation of a thermally responsive member, with the movable body in a more stable state.

[0008] The objective of the present invention is to provide a configuration for a manually resettable thermal protector that can operate more reliably by engaging the engaging member with the moving body in a more stable manner.

[0009] A manually resettable thermal protector according to one embodiment of the present invention is a thermal protector that shuts off an electrical circuit in response to heat generation and can be manually reset after the electrical circuit has been shut off. The manually resettable thermal protector comprises a pair of lead terminals arranged with their ends spaced apart and constituting a part of the electrical circuit; a movable body that is movable relative to the pair of lead terminals; a connecting terminal disposed between the pair of lead terminals and the movable body; a coil spring that applies a biasing force to the connecting terminal such that it separates the connecting terminal from the pair of lead terminals; a heat-sensitive member that deforms in a direction intersecting the direction of movement of the movable body when heated above a predetermined temperature; and an engaging member that holds the movable body so as to press the connecting terminal against the pair of lead terminals against the biasing force of the coil spring, and engages with the movable body at multiple positions such that the holding of the movable body is released by the deformation of the heat-sensitive member (first configuration).

[0010] As a result, the moving body is held in multiple places by the engaging member such that the connecting terminal is pressed against the pair of lead terminals against the biasing force of the coil spring. When the connecting terminal is pressed against the pair of lead terminals, the pair of lead terminals are electrically connected by the connecting terminal, and current flows through the pair of lead terminals.

[0011] On the other hand, if the heat-sensitive member deforms in a direction intersecting the direction of movement of the moving body due to heat above a predetermined temperature, the deformation of the heat-sensitive member releases the engagement member from holding the moving body. As a result, the connecting terminal is separated from the pair of lead terminals by the biasing force of the coil spring. Therefore, the pair of lead terminals are electrically isolated, and no current flows through them.

[0012] In this way, by pushing the movable body and holding it with the engaging member so that the connection terminal approaches the pair of lead terminals while the connection terminal is spaced apart from them, the connection terminal can be held in a state pressed against the pair of lead terminals against the biasing force of the coil spring. In other words, the manually reset thermal protector can be restored from the interrupted state of the electrical circuit by pushing the movable body.

[0013] Therefore, with the above configuration, when heat above the predetermined temperature is generated, the pair of lead terminals are electrically separated by the deformation of the heat-responsive member, while the movable body is pushed in and engaged with the engaging member to return to its original position, thereby realizing a manually reset type thermal protector.

[0014] Furthermore, since the movable body is held at multiple points by the engaging members, it is held in a more stable state by the engaging members. Therefore, by engaging the engaging members with the movable body in a more stable state, a configuration of a manually resettable thermal protector that can operate more reliably can be realized.

[0015] In the first configuration described above, the multiple positions in which the engaging member engages with the moving body include positions on both sides of the central portion of the moving body when viewed in the direction of movement of the moving body (second configuration).

[0016] This allows the engaging member to engage with the moving body more stably. Therefore, the moving body can be held more securely by the engaging member. Thus, by engaging the engaging member with the moving body in a more stable manner, a configuration of a manually resettable thermal protector that can operate more reliably can be realized.

[0017] In the first or second configuration described above, the manually reset thermal protector further includes a fixed-side case that fixes the pair of lead terminals with their ends spaced apart and supports the coil spring, the thermally responsive member, and the engaging member. The movable body is a movable-side case that is movable relative to the fixed-side case (third configuration).

[0018] This allows the pair of lead terminals, coil spring, thermally responsive member, and engaging member to be supported by the fixed-side case, while the movable-side case, which is movable relative to the fixed-side case, can be engaged and held by the engaging member. By releasing the engagement by the engaging member through deformation of the thermally responsive member, the movable-side case can be moved, separating the connection terminal from the pair of lead terminals. Furthermore, by pressing the movable-side case, the engaging member can be re-engaged with the movable-side case, pressing the connection terminal against the pair of lead terminals.

[0019] Thus, with the above configuration, the fixed case and the movable case, which are the cases for the manually reset thermal protector, can be used to achieve contact and separation between the connection terminal and the pair of lead terminals, as well as manual reset. Moreover, by using the fixed case and the movable case, the rigidity of the entire device can be ensured.

[0020] Therefore, a manually resettable thermal protector can be realized with a simple configuration while ensuring rigidity.

[0021] In the third configuration described above, the movable case has a movable top plate portion that covers the pair of lead terminals, a pair of movable side wall portions that extend in the direction of movement opposite to each other from both ends of the movable top plate portion, and a pair of engaged portions provided on the pair of movable side wall portions. The engaging member has a pair of claw portions that engage with the pair of engaged portions. The heat-responsive member undergoes deformation that displaces the pair of claw portions in such a way as heat above a predetermined temperature disengages the engagement with the pair of engaged portions (fourth configuration).

[0022] This allows the pair of engaged portions of the movable case to be held more stably by the pair of claws of the engaging member, while the deformation of the heat-sensitive member can release the engagement of the pair of claws with the pair of engaged portions. Therefore, while the movable case is held more stably relative to the fixed case, when heat at a predetermined temperature that causes deformation of the heat-sensitive member is transferred, the engagement of the engaging member with the movable case can be released.

[0023] In the fourth configuration described above, the thermally responsive member has a plate-shaped thermally responsive member bottom supported by the fixed-side case, and a pair of thermally responsive member wall portions extending from both ends of the thermally responsive member bottom in the thickness direction of the thermally responsive member bottom, facing each other, and deforming in a direction intersecting the direction of movement due to heat above a predetermined temperature. The engaging member has a plate-shaped engaging member bottom having an engaging member support portion supported by the fixed-side case, and a pair of engaging member wall portions extending from both ends of the engaging member bottom in the thickness direction of the engaging member bottom, facing each other. The pair of claw portions are provided at the tips of the pair of engaging member wall portions. The pair of thermally responsive member wall portions are positioned in a direction intersecting the direction of movement with respect to the pair of engaging member wall portions so that the engagement between the pair of claw portions and the pair of engaged portions can be released by the deformation (fifth configuration).

[0024] As a result, the heat-sensitive member deforms in a direction intersecting the direction of movement of the moving case when heated above a predetermined temperature. This deformation causes the pair of engaging member walls of the engaging member to deform in a direction that releases the engagement of the pair of claws with the pair of engaged parts of the moving case. Therefore, the deformation of the heat-sensitive member can more reliably release the engagement between the pair of claws and the pair of engaged parts.

[0025] In the fifth configuration described above, the pair of engaged portions of the movable case are provided on the device-inward side of the pair of movable side walls. The engaging member is arranged such that the pair of engaging member walls extend along the pair of thermal-responsive member walls at a position inward of the device relative to the pair of thermal-responsive member walls of the thermal-responsive member, and the bottom of the engaging member overlaps the thermal-responsive member bottom of the thermal-responsive member in the thickness direction at a position inward of the device. The pair of claws of the engaging member extend outward of the device and engage with the pair of engaged portions of the movable case (sixth configuration).

[0026] As a result, the heat-sensitive member deforms due to heat above a predetermined temperature, causing the wall portion of the heat-sensitive member to tilt inward into the device. This pushes the pair of engagement member walls of the engagement member inward, releasing the engagement between the pair of claw portions of the engagement member and the pair of engaged portions on the moving case. Therefore, the release of the engagement between the pair of claw portions and the pair of engaged portions using the heat-sensitive member can be easily achieved.

[0027] In the sixth configuration described above, the fixed case has a fixed case bottom that supports the thermally responsive member and the engaging member. The coil spring is supported by the fixed case bottom and also penetrates the bottom of the thermally responsive member and the bottom of the engaging member in the thickness direction, respectively, to support the connecting terminal (seventh configuration).

[0028] This allows the heat-responsive member, engaging member, and coil spring to be compactly arranged in the direction of movement of the movable case, and also makes it easy to realize a manually resettable thermal protector that can be returned to its original position by pushing the movable case against the biasing force of the coil spring.

[0029] In the seventh configuration described above, the fixed-side case has a fixed-side holding portion located between the bottom of the engaging member and the pair of lead terminals. The fixed-side holding portion has a through hole through which the coil spring passes (eighth configuration).

[0030] This allows the engaging member and the pair of lead terminals to be positioned in the direction of movement of the movable case by the fixed case. Furthermore, the through hole that penetrates the fixed spacer portion functions as a guide for the coil spring.

[0031] Therefore, a manually resettable thermal protector can be realized with a compact configuration.

[0032] In any one of the first to eighth configurations described above, the connecting terminal is made of an arched leaf spring whose central portion in a direction intersecting the direction of movement is spaced further apart from the pair of lead terminals than the ends (the ninth configuration).

[0033] This allows the end of the connection terminal in the direction intersecting the direction of movement of the moving case to be pressed against the pair of lead terminals more reliably when the moving case presses the connection terminal against the pair of lead terminals. Therefore, the connection terminal and the pair of lead terminals can be electrically connected more reliably.

[0034] A manually resettable thermal protector according to one embodiment of the present invention comprises: a pair of lead terminals arranged with their ends spaced apart and constituting a part of the circuit; a movable body movable relative to the pair of lead terminals; a connecting terminal disposed between the pair of lead terminals and the movable body; a coil spring that applies a biasing force to the connecting terminal such that it separates the connecting terminal from the pair of lead terminals; a thermally responsive member that deforms in a direction intersecting the direction of movement of the movable body when heated above a predetermined temperature; and an engaging member that holds the movable body so as to press the connecting terminal against the pair of lead terminals against the biasing force of the coil spring, and engages with the movable body at multiple positions such that the holding of the movable body is released by the deformation of the thermally responsive member.

[0035] This enables the realization of a manually resettable thermal protector that electrically separates a pair of lead terminals by deformation of a heat-sensitive member when heat above a predetermined temperature is generated, while simultaneously returning to its original position by pushing the movable body and engaging it with the engaging member. Furthermore, by engaging the engaging member with the movable body in a more stable manner, a configuration of a manually resettable thermal protector that can operate more reliably can be realized.

[0036] Figure 1 is a perspective view showing a schematic configuration of a manually resettable thermal protector according to an embodiment of the present invention. Figure 2 is an exploded perspective view of the manually resettable thermal protector. Figure 3 is a cross-sectional view of the manually resettable thermal protector when it is cut along the line III-III in Figure 1. Figure 4 is a cross-sectional view of the manually resettable thermal protector when it is cut along the line IV-IV in Figure 3. Figure 5 is a perspective view showing the engaging member and the heat-responsive member (described later) superimposed in the thickness direction. Figure 6 is a diagram corresponding to Figure 3 showing the current interruption state of the manually resettable thermal protector. Figure 7 is a cross-sectional view of the manually resettable thermal protector when it is cut along the line VII-VII in Figure 6. Figure 8 is a diagram corresponding to Figure 3 showing the reset operation of the manually resettable thermal protector.

[0037] The following describes each embodiment with reference to the drawings. In each drawing, the same parts are denoted by the same reference numerals, and the description of those parts will not be repeated. Note that the dimensions of the components in each drawing do not faithfully represent the dimensions of the actual components or the dimensional ratios of each component.

[0038] In the following description, the direction of movement refers to the direction of movement of the movable case relative to the fixed case (in this embodiment, the vertical direction). The "inside of the device" refers to the direction from the outside toward the center of the manually resettable thermal protector. The "outside of the device" refers to the direction from the center of the manually resettable thermal protector toward the outside. In the following description, for convenience of explanation, the vertical direction and the left-right direction may be used, but these descriptions do not limit the configuration, arrangement, and usage of the device.

[0039] (Manual Reset Thermal Protector) Figure 1 is a perspective view showing the schematic configuration of a manual reset thermal protector 1 according to an embodiment of the present invention. Figure 2 is an exploded perspective view of the manual reset thermal protector 1. Figure 3 is a cross-sectional view of the manual reset thermal protector 1 when it is cut along the line III-III in Figure 1. Figure 4 is a cross-sectional view of the manual reset thermal protector 1 when it is cut along the line IV-IV in Figure 3. The manual reset thermal protector 1 is installed in an electrical circuit and is configured to interrupt the current flowing through the electrical circuit when the temperature exceeds a predetermined temperature. Furthermore, the manual reset thermal protector 1 is configured to be able to return from the interrupted state to a state in which current flows through the circuit by manual operation.

[0040] As shown in Figures 1 to 4, the manually reset thermal protector 1 includes a fixed case 10, a movable case (movable body) 20, a pair of lead terminals 30, a connecting terminal 40, a retaining plate 45, a coil spring 50, a thermally responsive member 60, and an engaging member 70.

[0041] (Fixed-side case) The fixed-side case 10 constitutes the case of the manual reset type thermal protector 1 together with the movable-side case 20 described later. The fixed-side case 10 supports a pair of lead terminals 30, connection terminals 40, coil springs 50, thermal response members 60, and engagement members 70. Further, the fixed-side case 10 supports the movable-side case 20 movably. Note that the fixed-side case 10 is a resin part formed by injection molding together with the pair of lead terminals 30. In the following description, the direction in which the movable-side case 20 moves with respect to the fixed-side case 10 is referred to as the moving direction. In the present embodiment, the moving direction is the vertical direction.

[0042] Specifically, the fixed-side case 10 has a fixed-side case bottom portion 11 and a fixed-side case main body portion 15.

[0043] As shown in FIG. 2, the fixed-side case bottom portion 11 is in a rectangular frame shape in plan view and is fixed to the lower end portion of the fixed-side case main body portion 15. The fixed-side case bottom portion 11 has a rectangular case bottom opening 11a formed in the central portion in plan view and a heat transfer plate 12 having a substantially rectangular shape in plan view. The case bottom opening 11a is covered by the heat transfer plate 12. The heat transfer plate 12 is a member for transferring heat generated in an electric circuit or the like (not shown) to the thermal response member 60 described later. The heat transfer plate 12 is made of a material with good heat transfer rate such as stainless steel or copper, for example.

[0044] The thermal response member 60 described later is disposed on the heat transfer plate 12 of the fixed-side case bottom portion 11. Further, the fixed-side case bottom portion 11 supports the engagement member 70 described later. Thus, the fixed-side case bottom portion 11 supports the thermal response member 60 and the engagement member 70. Furthermore, the heat transfer plate 12 also supports the coil spring 50 described later.

[0045] The fixed-side case main body portion 15 has a pair of opposed fixed-side case wall portions 16, a connecting portion 17 (fixed-side holding portion), and a guide portion 18. In the present embodiment, the pair of fixed-side case wall portions 16, the connecting portion 17, and the guide portion 18 are integrally formed. Note that the pair of fixed-side case wall portions 16, the connecting portion 17, and the guide portion 18 may be configured separately.

[0046] The pair of fixed-side case wall portions 16 extend in the vertical direction in a facing state. That is, the pair of fixed-side case wall portions 16 extend in the thickness direction with respect to the fixed-side case bottom portion 11. The pair of fixed-side case wall portions 16 are rectangular flat plates, are connected by a connecting portion 17 described later, and the lower ends in the longitudinal direction are also connected. Each of the pair of fixed-side case wall portions 16 has a through hole 16a (see FIG. 2) through which the lead terminal 30 penetrates. The through hole 16a is formed in the fixed-side case wall portion 16 in a slit shape extending in the longitudinal direction of the fixed-side case wall portion 16. In the through hole 16a, a pair of columnar portions 16b for preventing the lead terminal 30 from coming out are provided so as to extend in the vertical direction and penetrate the lead terminal 30 in the thickness direction so that the lead terminal 30 does not come out laterally with respect to the fixed-side case main body portion 15.

[0047] On the upper part of the pair of fixed-side case wall portions 16, a stopper 16c is provided. The stopper 16c defines the upper limit of the movable range of the movable-side case 20 when the movable-side case 20 described later moves upward. That is, when the movable-side case 20 moves upward with respect to the fixed-side case 10, it moves to a position where it hits the stopper 16c.

[0048] The fixed-side case bottom portion 11 is connected to the lower ends of the pair of fixed-side case wall portions 16. The fixed-side case bottom portion 11 may be connected to the pair of fixed-side case wall portions 16 by engagement, or may be connected by joining such as adhesion.

[0049] The connecting portion 17 connects the pair of fixed-side case wall portions 16 over their longitudinal directions. As shown in FIG. 3, the connecting portion 17 has a connecting plate portion 17a, a fixed-side spacer portion 17b, and a through hole 17c. As shown in FIG. 4, the connecting plate portion 17a is plate-shaped for connecting the pair of fixed-side case wall portions 16. The connecting plate portion 17a supports the ends of a pair of lead terminals 30 that penetrate through the through holes 16a provided in the pair of fixed-side case wall portions 16 in a separated state. Therefore, the pair of lead terminals 30 are supported by the fixed-side case 10 with their ends separated from each other.

[0050] As shown in Figure 3, the fixed-side spacer portion 17b is provided so as to protrude from the connecting plate portion 17a toward the fixed-side case bottom portion 11. The fixed-side spacer portion 17b is a substantially rectangular parallelepiped that extends longitudinally along the pair of fixed-side case wall portions 16 between the pair of fixed-side case wall portions 16. The fixed-side spacer portion 17b is a member that contacts the engaging member 70 when the pair of claw portions 73 of the engaging member 70 (described later) are engaged with the pair of engaged portions 23 of the movable-side case 20, thereby suppressing the upward movement of the engaging member 70. In this embodiment, in the vertical direction, the position of the lower end of the fixed-side spacer portion 17b is lower than the position of the lower ends of the pair of fixed-side case wall portions 16.

[0051] The through-hole 17c penetrates the central portion of the connecting portion 17 in the longitudinal direction in the vertical direction. That is, the through-hole 17c penetrates the connecting plate portion 17a and the fixed-side spacer portion 17b in the direction of the protrusion of the fixed-side spacer portion 17b. A coil spring 50, which will be described later, is positioned to pass through the through-hole 17c. Therefore, the axis P of the coil spring 50 extends in the vertical direction.

[0052] The guide portion 18 functions as a guide when the movable case 20 moves relative to the fixed case 10. As shown in Figures 1 and 2, the guide portion 18 is provided on opposing surfaces of a pair of fixed case wall portions 16 so as to extend in the vertical direction. In this embodiment, a pair of guide portions 18 are provided on the fixed case wall portion 16, side by side in the longitudinal direction, and have a rectangular cross-section when viewed in the vertical direction. The guide portion 18 is provided at the same position as the columnar portion 16b provided in the through hole 16a of the fixed case wall portion 16 described above. The guide portion 18 is located in the notch portion 21a of the movable top plate portion 21 of the movable case 20, which will be described later. As a result, when the movable case 20 moves vertically relative to the fixed case 10, the guide portion 18 functions as a guide for the movable case 20.

[0053] (Movable Case) As shown in Figure 1, the movable case 20, together with the fixed case 10, constitutes the case of the manually reset thermal protector 1. The movable case 20 is configured to be movable in the vertical direction relative to the fixed case 10. More specifically, the movable case 20 is movable in the vertical direction between a pair of fixed case walls 16 of the fixed case 10.

[0054] The moving case 20 engages with the engaging member 70 (described later) at multiple positions (two positions in this embodiment) at its lower end position in the direction of movement, pressing the connection terminal 40 against the pair of lead terminals 30. When the engagement with the engaging member 70 is released, it moves upward.

[0055] As shown in Figures 1 to 3, the movable case 20 has a movable top plate portion 21, a pair of movable side wall portions 22, and a pair of engaging portions 23. In this embodiment, the movable top plate portion 21, the pair of movable side wall portions 22, and the pair of engaging portions 23 are integrally formed. However, the movable top plate portion 21, the pair of movable side wall portions 22, and the pair of engaging portions 23 may be constructed as separate parts.

[0056] The movable top plate portion 21 is a rectangular flat plate in plan view and is positioned to cover the connecting plate portion 17a of the fixed case 10, as shown in Figure 4. Therefore, the movable top plate portion 21 is positioned to cover the pair of lead terminals 30 supported by the connecting plate portion 17a. As shown in Figure 2, the movable top plate portion 21 has a notch portion 21a on the long side through which the guide portion 18 of the fixed case 10 described above passes. In this embodiment, two notches 21a are provided on each of the pair of long sides of the movable top plate portion 21.

[0057] As shown in Figures 1 to 3, the movable top plate portion 21 has through-holes 21b at both ends in the longitudinal direction, which penetrate in the thickness direction. These through-holes 21b allow visual confirmation of whether the claw portion 73 of the engaging member 70 is engaged with the engaged portion 23 of the movable case 20, which will be described later.

[0058] The pair of movable side wall portions 22 extend from both ends in the longitudinal direction of the movable top plate portion 21 toward the fixed case bottom portion 11 of the fixed case 10. The pair of movable side wall portions 22 are located at the ends in the longitudinal direction of the top plate through hole 21b. As shown in Figure 3, the tips of the pair of movable side wall portions 22 are provided with a pair of engaging portions 23 on the inward side of the device. The pair of movable side wall portions 22 are arranged to sandwich the connecting portion 17 of the fixed case 10 in the longitudinal direction. As a result, the engaging portions 23 are located on one and the other in the longitudinal direction relative to the connecting portion 17 of the fixed case 10.

[0059] The pair of movable side wall portions 22 have a vertical length such that, when the pair of claw portions 73 of the engaging member 70 are engaged with the pair of engaged portions 23 of the movable side case 20, that is, when the manually reset type thermal protector 1 is in the state shown in Figures 1, 3, and 4, the pair of engaged portions 23 are located below the connecting plate portion 17a. The pair of movable side wall portions 22 have the same vertical length.

[0060] As shown in Figure 3, the pair of engaged portions 23 are provided at the tips of the pair of movable side wall portions 22 so as to protrude inward into the device. More specifically, the pair of engaged portions 23 protrude inward into the device from the tips of the pair of movable side wall portions 22 and are hook-shaped with an engaging surface 23a on their upper part into which the pair of claw portions 73 of the engaging member 70 catch. The engaging surface 23a is located below the connecting plate portion 17a when the claw portions 73 of the engaging member 70 are engaged with the pair of engaged portions 23 on the movable side case 20.

[0061] As described above, the pair of engaged portions 23 are located on one and the other in the longitudinal direction relative to the connecting portion 17 of the fixed-side case 10. Therefore, the engagement positions where the pair of claw portions 73 of the engagement member 70 engage with the pair of engaged portions 23 are, in a plan view, on one and the other in the longitudinal direction, straddling the connecting portion 17 of the fixed-side case 10. Furthermore, when viewing the movable-side case 20 in the direction of movement, these engagement positions are on both sides in the longitudinal direction, straddling the central portion of the movable-side case 20. This allows the engagement member 70 to engage with the movable-side case 20 more stably. Thus, the movable-side case 20 can be held more securely by the engagement member 70.

[0062] (Lead terminals) As shown in Figures 1, 2, and 4, each pair of lead terminals 30 is formed in a crank shape, with one end 31 and the other end 32 bending in opposite directions in the thickness direction. The pair of lead terminals are made of, for example, a copper alloy.

[0063] A pair of lead terminals 30 are fixed to the fixed case 10 such that one end 31 is located inside the fixed case 10 and the other end 32 is located outside the fixed case 10. The other end 32 of the pair of lead terminals 30 is electrically connected to an electrical circuit (not shown). The other end 32 of the pair of lead terminals 30 is located at the same vertical position as the bottom 11 of the fixed case 10 or below the bottom 11 of the fixed case 10. Preferably, the other end 32 of the pair of lead terminals 30 is located below the bottom 11 of the fixed case.

[0064] One end 31 of a pair of lead terminals 30 is fixed to the connecting plate portion 17a by a pair of fixed-side case walls 16 in the fixed-side case 10 so as to be spaced apart. Therefore, since the pair of lead terminals 30 are not directly electrically connected, no current flows between the pair of lead terminals 30 unless the connecting terminal 40, described later, makes contact with one end 31 of the pair of lead terminals 30 so as to straddle it. In this embodiment, one end 31 is attached to the connecting plate portion 17a such that its upper surface is flush with the upper surface of the connecting plate portion 17a.

[0065] As shown in Figure 2, one end 31 of the pair of lead terminals 30 is provided with a lead terminal through-hole 31a that penetrates in the thickness direction. A columnar portion 16b, provided in the through-hole 16a of the fixed-side case wall 16, passes through this lead terminal through-hole 31a. As a result, the pair of lead terminals 30 cannot come loose from the fixed-side case wall 16, and are therefore more securely fixed to the fixed-side case 10.

[0066] (Connection terminal) As shown in Figure 4, the connection terminal 40 is located above the pair of lead terminals 30 and electrically connects or disconnects the pair of lead terminals 30 by making contact with or separating from the pair of lead terminals 30 as the movable case 20 moves. In other words, the connection terminal 40 is a component for switching between conductivity and non-conductivity of the pair of lead terminals 30.

[0067] As shown in Figures 2 and 3, the connection terminal 40 is a flat, substantially rectangular member in plan view. The connection terminal 40 is made of a metal material that is elastically deformable in the thickness direction and is conductive. The connection terminal 40 has one side in the longitudinal direction and the other side bent in the thickness direction relative to the central part in the longitudinal direction. The connection terminal 40 is made of an arch-shaped leaf spring in which both ends are bent in the thickness direction relative to the central part in the longitudinal direction. That is, the connection terminal 40 is made of an arch-shaped leaf spring in which the central part in the direction intersecting the movement direction of the movable case 20 (up and down direction in the figure) is spaced further apart from the pair of lead terminals 30 than the ends.

[0068] The connection terminal 40 has a longitudinal central portion 41 and a pair of connection portions 42.

[0069] The longitudinal central portion 41 is a flat plate with a size that allows the upper end of the coil spring 50, which will be described later, to make contact with it. By the upper end of the coil spring 50 contacting the longitudinal central portion 41, the connection terminal 40 is biased upward by the elastic restoring force of the coil spring 50. The upper surface of the longitudinal central portion 41 is in contact with the flat retaining plate 45.

[0070] Here, the retaining plate 45 is a flat metal member and is positioned between the movable-side top plate portion 21 of the movable-side case 20 and the connecting terminal 40. This ensures that when the movable-side top plate portion 21 of the movable-side case 20 presses the connecting terminal 40 against the pair of lead terminals 30, force can be reliably transmitted from the movable-side top plate portion 21 to the connecting terminal 40. As shown in Figure 2, the retaining plate 45 is also provided with a notch 45a to avoid interference with the pair of guide portions 18 provided on the fixed-side case wall portion 16 of the fixed-side case 10.

[0071] The longitudinal central portion 41 has terminal protrusions 41a on both sides of the connection terminal 40 in the short direction, which protrude in the short direction more than the pair of connection portions 42. The terminal protrusions 41a are rectangular in shape in plan view and are located between a pair of guide portions 18 provided on the fixed side case wall portion 16 of the fixed side case 10. As a result, the connection terminal 40 is supported in a position longitudinally relative to the fixed side case 10.

[0072] The pair of connecting portions 42 are located on one side and the other side of the longitudinal direction relative to the longitudinal center portion 41 of the connection terminal 40. Therefore, the longitudinal center portion 41 is located between the pair of connecting portions 42. Each of the pair of connecting portions 42 is rectangular in plan view. The pair of connecting portions 42 are bent in one direction in the thickness direction relative to the longitudinal center portion 41. That is, the pair of connecting portions 42 are inclined such that their longitudinal ends are located one direction in the thickness direction relative to the longitudinal center portion 41. In this way, the connection terminal 40 is configured in an arch shape in which the longitudinal center portion protrudes in the thickness direction compared to the ends.

[0073] As shown in Figures 2 and 3, each of the pair of connecting portions 42 has a terminal contact portion 42a at its longitudinal end that protrudes in one direction in the thickness direction. The terminal contact portion 42a is formed on one surface of the connecting portion 42 in the thickness direction, extending in the width direction of the connecting terminal 40. As shown in Figure 4, the terminal contact portion 42a is positioned to straddle one end 31 of the pair of lead terminals 30. The terminal contact portion 42a is made of a metal material with lower electrical resistance than the connecting portion 42, such as silver.

[0074] With the above configuration, as shown in Figures 1, 3, and 4, the pair of claws 73 of the engaging member 70 are engaged with the pair of engaged portions 23 of the movable case 20, and the connecting terminal 40 is pressed against the pair of lead terminals 30 by the movable case 20, so that the terminal contact portion 42a located at the longitudinal end of the pair of connecting portions 42 is in contact with the pair of lead terminals 30. As a result, the pair of lead terminals 30 are electrically connected via the connecting terminal 40.

[0075] Furthermore, as described above, by arranging the connection terminal 40 in an arch shape, when the connection terminal 40 is pressed from above by the movable case 20, the terminal contact portion 42a located at the longitudinal end of the connection terminal 40 can be made to contact the pair of lead terminals 30 more reliably.

[0076] (Coil Spring) As shown in Figure 3, the coil spring 50 is a spring member in which a wire extends in a spiral shape, and is a so-called compression spring. The lower end of the coil spring 50 is supported by the heat transfer plate 12 on the bottom 11 of the fixed case 10. The coil spring 50 passes through through holes 61a and 71b provided in the heat-responsive member 60 and the engaging member 70, respectively, which will be described later, and also passes through the through hole 17c of the connecting portion 17. The upper end of the coil spring 50 is in contact with the connecting terminal 40. That is, the coil spring 50 is supported by the fixed case 10 and elastically supports the connecting terminal 40.

[0077] The coil spring 50 is compressed in the axial direction when the pair of claws 73 of the engaging member 70 are engaged with the pair of engaged portions 23 in the movable case 20, and extends back to its original length when the engagement of the pair of claws 73 of the engaging member 70 with the pair of engaged portions 23 in the movable case 20 is released (see Figure 6).

[0078] Therefore, when the engagement of the pair of claws 73 of the engaging member 70 with respect to the pair of engaged portions 23 on the moving case 20 is released, the connecting terminal 40 moves apart from the pair of lead terminals 30 by the coil spring 50. In this way, the coil spring 50 can more reliably disconnect the electrical connection between the pair of lead terminals 30 by the connecting terminal 40.

[0079] (Engaging Member) As shown in Figure 3, the engaging member 70 is supported by the fixed-side case 10 and engages with the engaged portion 23 of the movable-side case 20. The engaging member 70 is configured such that its engagement with the engaged portion 23 of the movable-side case 20 is released by the deformation of the thermally responsive member 60, which will be described later.

[0080] More specifically, as shown in Figures 2, 3, and 5, the engaging member 70 has an engaging member bottom portion 71, a pair of engaging member wall portions 72, and a pair of claw portions 73. Figure 5 is a perspective view showing the engaging member 70 and the heat-responsive member 60 (described later) superimposed in the thickness direction.

[0081] The bottom portion 71 of the engaging member is a flat plate with a substantially rectangular shape in plan view. The bottom portion 71 of the engaging member has engaging member support portions 71a that protrude longitudinally at the four corners, and a through hole 71b in the center in plan view through which the coil spring 50 passes. The engaging member support portions 71a are supported by the bottom portion 11 of the fixed-side case 10. Thus, the engaging member 70 is supported by the fixed-side case 10.

[0082] As shown in Figure 3, the bottom portion 71 of the engaging member is in contact with the lower end of the fixed-side spacer portion 17b of the fixed-side case 10, with the pair of claw portions 73 of the engaging member 70 engaged with the pair of engaged portions 23 of the movable-side case 20. As a result, the movable-side case 20 is fixed to the fixed-side case 10 via the engaging member 70, with the pair of claw portions 73 of the engaging member 70 engaged with the pair of engaged portions 23 of the movable-side case 20. With the above configuration, the connecting portion 17 of the fixed-side case 10 is located between the bottom portion 71 of the engaging member and the pair of lead terminals 30, and functions as a fixed-side holding portion that holds the bottom portion 71 of the engaging member and the pair of lead terminals 30.

[0083] The pair of engaging member walls 72 protrude from both ends in the longitudinal direction of the engaging member bottom 71 in one direction (upward) in the thickness direction of the engaging member bottom 71. The pair of claws 73 are provided at the tips of the pair of engaging member walls 72. The pair of claws 73 extend from the pair of engaging member walls 72 in the longitudinal direction and are configured to engage with the pair of engaged portions 23 in the movable case 20. When the engaging member 70 is viewed in plan, one of the pair of claws 73 extends in one direction in the longitudinal direction, and the other of the pair of claws 73 extends in the other direction in the longitudinal direction.

[0084] The pair of engaging member wall portions 72 have a length such that, when the pair of claw portions 73 of the engaging member 70 are engaged with the pair of engaged portions 23 of the movable case 20, the bottom portion 71 of the engaging member contacts the lower end of the fixed-side spacer portion 17b of the fixed-side case 10.

[0085] As shown in Figures 2 and 5, the pair of engaging member wall portions 72 are provided at both ends in the longitudinal direction of the engaging member bottom portion 71, in the central portion in the width direction (short direction) of the engaging member 70. A notch 71c is provided between the engaging member wall portion 72 and the engaging member support portion 71a at the engaging member bottom portion 71. This notch 71c allows the engaging member wall portion 72 to be easily deformed relative to the engaging member bottom portion 71.

[0086] The engaging member 70 is made of a material that is more easily deformable than the thermally responsive member 60, that is, a material with a lower Young's modulus than the thermally responsive member 60. The engaging member 70 is made of, for example, a copper alloy.

[0087] (Thermal Responding Member) The thermal responding member 60 is flat and composed of a so-called bimetal, which is made by bonding multiple types of metals having different coefficients of thermal expansion in the thickness direction. In the thermal responding member 60 of this embodiment, the coefficient of thermal expansion of the metal located on the lower side in the thickness direction is greater than the coefficient of expansion of the metal located on the upper side. Therefore, when the thermal responding member 60 reaches a predetermined temperature or higher, it deforms so that the central part in the longitudinal direction moves downward.

[0088] As shown in Figure 3, the heat-sensitive member 60 is supported by the fixed-side case 10 and is positioned below the engaging member 70 so as to overlap it in the thickness direction. The heat-sensitive member 60 undergoes the deformation described above at a temperature above a predetermined temperature, deforming the pair of engaging member walls 72 on the engaging member 70, thereby releasing the engagement of the pair of claws 73 with the pair of engaged portions 23 on the movable-side case 20.

[0089] More specifically, the thermally responsive member 60 has a thermally responsive member bottom portion 61 and a pair of thermally responsive member wall portions 62.

[0090] As shown in Figures 2 and 5, the bottom portion 61 of the thermally responsive member is a rectangular flat plate in plan view. The bottom portion 61 of the thermally responsive member is curved so that its central part in the longitudinal direction protrudes upward in the thickness direction. As shown in Figure 3, the bottom portion 61 of the thermally responsive member is positioned on the heat transfer plate 12 such that both ends in the longitudinal direction are in contact with the heat transfer plate 12 of the fixed-side case bottom portion 11. As a result, heat is transferred to the bottom portion 61 of the thermally responsive member via the heat transfer plate 12. When heat above a predetermined temperature is transferred to the bottom portion 61 of the thermally responsive member via the heat transfer plate 12, the central part in the longitudinal direction deforms so that it moves downward in the thickness direction (see Figure 6).

[0091] As shown in Figure 3, the bottom portion 61 of the heat-responsive member has a through hole 61a in the central part when viewed from above, through which the coil spring 50 passes.

[0092] The pair of thermally responsive member wall portions 62 protrude from both ends in the longitudinal direction of the thermally responsive member bottom portion 61 in one direction (upward) in the thickness direction of the thermally responsive member bottom portion 61. As shown in Figures 2 and 5, the pair of thermally responsive member wall portions 62 are located outward in the longitudinal direction relative to the pair of engaging member wall portions 72 on the engaging member 70 and extend along the pair of engaging member wall portions 72. That is, the pair of engaging member wall portions 72 are located inward relative to the pair of thermally responsive member wall portions 62 and extend along the pair of thermally responsive member wall portions 62.

[0093] When the longitudinal central portion of the bottom portion 61 of the heat-responsive member deforms due to heat above a predetermined temperature as described above, causing it to move downward in the thickness direction, the tips of the pair of heat-responsive member wall portions 62 move so as to tilt inward towards the device, as shown by the black arrows in Figures 5 and 6. That is, the tips of the pair of heat-responsive member wall portions 62 move in a direction intersecting the direction of movement of the moving case 20, so as to move closer to each other.

[0094] As a result, the pair of engaging member walls 72 in the engaging member 70, which is positioned to overlap the thermally responsive member 60, are pushed inward by the pair of thermally responsive member walls 62 in the thermally responsive member 60. The thermally responsive member bottom 61 of the thermally responsive member 60 is configured such that by moving the pair of thermally responsive member walls 62 inward, the pair of engaging member walls 72 are deformed, thereby releasing the engagement between the pair of claws 73 and the engaged portion 23 of the moving-side case 20.

[0095] Furthermore, in the pair of heat-responsive member wall portions 62, the thermal expansion coefficient of the metal located on the outside is greater than that of the metal located on the inside. In addition, it is preferable that the pair of heat-responsive member wall portions 62 are bent at an angle of 90 degrees or more with respect to the bottom portion 61 of the heat-responsive member.

[0096] The length of the pair of heat-sensitive member wall portions 62 is longer than half the vertical length of the pair of engaging member wall portions 72 and is such that it does not come into contact with the pair of claw portions 73 on the engaging member 70. As a result, when the longitudinal central portion of the bottom portion 61 of the heat-sensitive member deforms to move downward in the thickness direction, as described above, the pair of heat-sensitive member wall portions 62 move inward into the device, allowing the pair of engaging member wall portions 72 to move inward more reliably. Therefore, the movement of the pair of heat-sensitive member wall portions 62 allows for more reliable disengagement between the pair of claw portions 73 on the engaging member 70 and the engaged portion 23 of the moving case 20.

[0097] (Current interruption and recovery operation of the manually reset thermal protector) Next, the current interruption and recovery operation of the manually reset thermal protector 1 having the above configuration will be described. Figure 6 is a diagram equivalent to Figure 3 showing the current interruption state of the manually reset thermal protector 1. Figure 7 is a cross-sectional view of the manually reset thermal protector 1 when it is cut along the line VII-VII in Figure 6.

[0098] In the manually reset type thermal protector 1, when heat above a predetermined temperature is transferred to the heat transfer plate 12 of the fixed-side case 10, as shown in Figure 6, the bottom portion 61 of the thermal-responsive member 60 deforms such that the longitudinal central portion moves downward in the thickness direction. As a result, the pair of thermal-responsive member walls 62 of the thermal-responsive member 60 move inward into the device as indicated by the black arrows, deforming the pair of engaging member walls 72 of the engaging member 70 inward into the device. This deformation of the pair of engaging member walls 72 releases the engagement of the pair of claw portions 73 of the engaging member 70 with the engaged portion 23 of the movable-side case 20.

[0099] As a result, as shown by the white arrows in Figures 6 and 7, the elastic restoring force of the coil spring 50 causes the movable case 20 to move upward relative to the fixed case 10, and the connecting terminal 40 to move upward away from the pair of lead terminals 30. The movable case 20 moves upward relative to the fixed case 10 to a position where it contacts the stopper 16c. This disconnects the electrical connection between the pair of lead terminals 30 by the connecting terminal 40, interrupting the current flowing through the electrical circuit to which the pair of lead terminals 30 are connected.

[0100] Figure 8 is a diagram corresponding to Figure 3 showing the reset operation of the manually reset thermal protector 1. When resetting the manually reset thermal protector 1, as shown by the white arrows in Figure 8, the movable case 20 is pushed downward against the fixed case 10 against the biasing force of the coil spring 50, and the pair of claws 73 of the engaging member 70 are engaged with the engaged portion 23 of the movable case 20. At this time, the temperature of the heat-sensitive member 60 must be lower than a predetermined temperature, and the pair of heat-sensitive member walls 62 must be returned to their original position (the position shown in Figure 3).

[0101] This allows the movable case 20 to be held relative to the fixed case 10 so that the movable case 20 presses the connection terminal 40 against the pair of lead terminals 30. Thus, the connection terminal 40 can electrically connect the pair of lead terminals 30. In this way, the manually resettable thermal protector 1 can be reset to a state where it can interrupt the current.

[0102] Based on the above, the manually resettable thermal protector 1 according to this embodiment is a thermal protector that shuts off an electrical circuit in response to heat generation and can be manually reset after the electrical circuit is shut off. The manually resettable thermal protector 1 includes a pair of lead terminals 30 that are spaced apart from each other and constitute a part of the electrical circuit, a movable case 20 that is movable relative to the pair of lead terminals 30, a connecting terminal 40 positioned between the pair of lead terminals 30 and the movable case 20, a coil spring 50 that applies a biasing force to the connecting terminal 40 such that it separates the connecting terminal 40 from the pair of lead terminals 30, a heat-sensitive member 60 that deforms in a direction intersecting the direction of movement of the movable case 20 when heated above a predetermined temperature, and an engaging member 70 that holds the movable case 20 so as to press the connecting terminal 40 against the pair of lead terminals 30 against the biasing force of the coil spring 50, and engages with the movable case 20 at multiple positions such that the holding of the movable case 20 is released by the deformation of the heat-sensitive member 60.

[0103] As a result, the movable case 20 is held in place at multiple points by the engaging member 70 such that the connecting terminal 40 is pressed against the pair of lead terminals 30 against the biasing force of the coil spring 50. When the connecting terminal 40 is pressed against the pair of lead terminals 30, the pair of lead terminals 30 are electrically connected by the connecting terminal 40, and current flows through the pair of lead terminals 30.

[0104] On the other hand, if the heat-sensitive member 60 deforms in a direction intersecting the direction of movement of the moving case 20 due to heat above a predetermined temperature, the deformation of the heat-sensitive member 60 releases the engagement member 70 from holding the moving case 20. As a result, the connecting terminal 40 is separated from the pair of lead terminals 30 by the biasing force of the coil spring 50. Therefore, the pair of lead terminals 30 are electrically isolated, and no current flows through the pair of lead terminals 30.

[0105] In this manner, by pushing the movable case 20 and holding it with the engaging member 70 so that the connection terminal 40 moves closer to the pair of lead terminals 30 while the connection terminal 40 is separated from the pair of lead terminals 30, the connection terminal 40 can be held in a state where it is pressed against the pair of lead terminals 30 against the biasing force of the coil spring 50. In other words, the manually reset type thermal protector 1 can be restored from the interrupted state of the electrical circuit by pushing the movable case 20.

[0106] Therefore, with the above configuration, when heat above a predetermined temperature is generated, the pair of lead terminals 30 are electrically separated by the deformation of the heat-responsive member 60, while the movable case 20 is pushed in and engaged with the engaging member 70 to return to its original position, thereby realizing a manually reset type thermal protector 1.

[0107] Furthermore, since the movable case 20 is held at multiple points by the engaging members 70, it is held in a more stable state by the engaging members 70. Therefore, by engaging the engaging members 70 with the movable case 20 in a more stable state, a configuration of a manually reset type thermal protector 1 that can operate more reliably can be realized.

[0108] Furthermore, in this embodiment, the multiple positions in which the engaging member 70 engages with the movable case 20 include positions on both sides of the central portion of the movable case 20 when viewed in the direction of movement of the movable case 20.

[0109] This allows the engaging member 70 to engage with the movable case 20 more stably. Therefore, the movable case 20 can be held more securely by the engaging member 70. Thus, by engaging the engaging member 70 with the movable case 20 in a more stable state, a configuration of a manually reset type thermal protector 1 that can operate more reliably can be realized.

[0110] In this embodiment, the manually reset thermal protector 1 further includes a fixed-side case 10 that fixes a pair of lead terminals 30 with their ends spaced apart, and supports a coil spring 50, a heat-responsive member 60, and an engaging member 70. The movable-side case 20 is movable relative to the fixed-side case 10.

[0111] As a result, the pair of lead terminals 30, the coil spring 50, the heat-sensitive member 60, and the engaging member 70 are supported by the fixed-side case 10, while the movable-side case 20, which is movable relative to the fixed-side case 10, can be engaged and held by the engaging member 70. By releasing the engagement by the engaging member 70 through the deformation of the heat-sensitive member 60, the movable-side case 20 can be moved, and the connection terminal 40 can be separated from the pair of lead terminals 30. Furthermore, by pressing the movable-side case 20, the engaging member 70 can be re-engaged with the movable-side case 20, and the connection terminal 40 can be pressed against the pair of lead terminals 30.

[0112] Thus, with the above configuration, the fixed case 10 and movable case 20, which are the cases of the manually reset thermal protector 1, can be used to achieve contact and separation between the connection terminal 40 and the pair of lead terminals 30, and manual reset can also be achieved. Moreover, by using the fixed case 10 and movable case 20, the rigidity of the entire device can be ensured.

[0113] Therefore, a manually resettable thermal protector 1 can be realized with a simple configuration while ensuring rigidity.

[0114] Furthermore, in this embodiment, the movable case 20 has a movable top plate portion 21 that covers a pair of lead terminals 30, a pair of movable side wall portions 22 that extend in the direction of movement opposite to each other from both ends of the movable top plate portion 21, and a pair of engaged portions 23 provided on the pair of movable side wall portions 22. The engaging member 70 has a pair of claw portions 73 that engage with the pair of engaged portions 23. The heat-sensitive member 60 undergoes deformation that displaces the pair of claw portions 73 when heated to a predetermined temperature or higher, thereby releasing the engagement with the pair of engaged portions 23.

[0115] As a result, the pair of engaged portions 23 of the movable case 20 can be held more stably by the pair of claw portions 73 of the engaging member 70, while the deformation of the heat-sensitive member 60 can release the engagement of the pair of claw portions 73 with the pair of engaged portions 23. Therefore, while the movable case 20 is held more stably against the fixed case 10, when heat at a predetermined temperature that causes deformation of the heat-sensitive member 60 is transferred, the engagement of the engaging member 70 with the movable case 20 can be released.

[0116] Furthermore, in this embodiment, the heat-responsive member 60 is supported by the fixed-side case 10 and has a plate-shaped heat-responsive member bottom portion 61 that is curved so that its central portion protrudes upward, and a pair of heat-responsive member wall portions 62 that extend from both ends of the heat-responsive member bottom portion 61 in the thickness direction of the heat-responsive member bottom portion 61, facing each other, and deform in a direction intersecting the direction of movement due to heat above a predetermined temperature. The pair of claw portions 73 are provided at the tips of the pair of engaging member wall portions 72. The pair of heat-responsive member wall portions 62 are positioned in a direction intersecting the direction of movement with respect to the pair of engaging member wall portions 72 so that the engagement between the pair of claw portions 73 and the pair of engaged portions 23 can be released by the deformation of the heat-responsive member 60.

[0117] As a result, the bottom portion 61 of the heat-sensitive member 60 deforms due to heat above a predetermined temperature, causing the central portion to move downward, and the pair of heat-sensitive member walls 62 move in a direction intersecting the direction of movement of the moving case 20. This movement of the pair of heat-sensitive member walls 62 can deform the pair of engaging member walls 72 of the engaging member 70 in a direction that releases the engagement of the pair of claws 73 with the pair of engaged portions 23 of the moving case 20. Therefore, the deformation of the heat-sensitive member 60 can more reliably release the engagement between the pair of claws 73 and the pair of engaged portions 23.

[0118] Furthermore, in this embodiment, the pair of engaged portions 23 of the movable case 20 are provided on the device-inward side of the pair of movable side wall portions 22. The engaging member 70 is arranged such that the pair of engaging member wall portions 72 extend along the pair of thermal-responsive member wall portions 62 of the thermal-responsive member 60 at a position inward of the device, and the engaging member bottom portion 71 overlaps the thermal-responsive member bottom portion 61 of the thermal-responsive member 60 in the thickness direction at a position inward of the device. The pair of claw portions 73 of the engaging member 70 extend outward of the device and engage with the pair of engaged portions 23 of the movable case 20.

[0119] As a result, the heat-sensitive member 60 deforms due to heat above a predetermined temperature, causing the heat-sensitive member wall portion 62 to tilt inward into the device. This pushes the pair of engaging member wall portions 72 on the engaging member 70 inward into the device, releasing the engagement of the pair of claw portions 73 with the pair of engaged portions 23 of the movable case 20. Therefore, the release of engagement between the pair of claw portions 73 and the engaged portions 23 using the heat-sensitive member 60 can be easily achieved.

[0120] Furthermore, in this embodiment, the fixed-side case 10 has a fixed-side case bottom 11 that supports the heat-responsive member 60 and the engaging member 70. The coil spring 50 is supported by the fixed-side case bottom 11 and also penetrates the heat-responsive member bottom 61 of the heat-responsive member 60 and the engaging member bottom 71 of the engaging member 70 in the thickness direction, supporting the connection terminal 40.

[0121] This allows the heat-responsive member 60, the engaging member 70, and the coil spring 50 to be compactly arranged in the direction of movement of the movable case 20, and also makes it easy to realize a manually reset type thermal protector 1 that returns to its original position by pushing the movable case 20 in.

[0122] Furthermore, in this embodiment, the fixed-side case 10 has a connecting portion 17 located between the bottom portion 71 of the engaging member 70 and the pair of lead terminals 30. The connecting portion 17 has a through hole 17c through which the coil spring 50 passes.

[0123] This allows the engaging member 70 and the pair of lead terminals 30 to be positioned in the direction of movement of the movable case 20 by the fixed case 10. Moreover, the through hole 17c that penetrates the connecting portion 17 functions as a guide for the coil spring 50.

[0124] Therefore, the manually reset type thermal protector 1 can be realized with a compact configuration.

[0125] Furthermore, in this embodiment, the connection terminal 40 is made of an arch-shaped leaf spring whose central portion in the direction intersecting the direction of movement is spaced further apart from the ends than the pair of lead terminals 30.

[0126] This allows the end of the connection terminal 40 in the direction intersecting the direction of movement of the moving case 20 to press the connection terminal 40 against the pair of lead terminals 30 more reliably when the moving case 20 presses the connection terminal 40 against the pair of lead terminals 30. Therefore, the connection terminal 40 and the pair of lead terminals 30 can be electrically connected more reliably.

[0127] [Other Embodiments] Although embodiments of the present invention have been described above, the embodiments described above are merely examples for carrying out the present invention. Therefore, the invention is not limited to the embodiments described above, and it is possible to carry out the invention by appropriately modifying the embodiments described above without departing from the spirit of the invention.

[0128] In the above embodiment, the movable case 20 moves relative to the fixed case 10. However, instead of the movable case, another movable body that can move relative to the fixed case may be used. For example, a plunger or a piston may be used as the other movable body.

[0129] In the above embodiment, the movable case 20 has a movable top plate portion 21, a pair of movable side wall portions 22, and a pair of engaged portions 23. However, the movable case is not limited to the above configuration as long as it is capable of engaging with the engaging member and can press the connecting terminals against the pair of lead terminals while engaged with the engaging member.

[0130] In the above embodiment, the movable case 20 is engaged with the engaging member 70 at two points. That is, a pair of claws 73 of the engaging member 70 engage with a pair of engaged portions 23 of the movable case 20. However, the movable case may be engaged with the engaging member at three or more points.

[0131] In the above embodiment, the engagement positions between the movable case 20 and the engaging member 70 are on both sides in the longitudinal direction of the movable case 20, with the central portion in between, when viewed in the direction of movement of the movable case 20. However, the engagement positions between the movable case and the engaging member may be at positions other than on both sides in the longitudinal direction of the central portion of the movable case, with the central portion in between, when viewed in the direction of movement of the movable case. The engagement positions between the movable case and the engaging member may be at any position that allows the movable case to be stably engaged and held.

[0132] In the above embodiment, the pair of engaging member walls 72 of the engaging member 70 are positioned inward relative to the pair of thermally responsive member walls 62 of the thermally responsive member 60, and as the pair of thermally responsive member walls 62 deform inward, the pair of engaging member walls 72 also deform inward, releasing the engagement between the pair of claws 73 and the engaged portion 23 of the movable case 20. However, another member may be placed between the thermally responsive member and the engaging member to transmit the deformation of the thermally responsive member to the engaging member.

[0133] In the above embodiment, the bottom portion 61 of the heat-responsive member 60 is curved such that its central portion protrudes upward. However, the bottom portion of the heat-responsive member may be curved such that its central portion protrudes downward, or it may not be curved, as long as the pair of heat-responsive member walls can be deformed by deformation due to heat above a predetermined temperature to the extent that the engagement between the pair of claw portions of the engaging member and the pair of engaged portions of the movable case is released.

[0134] In the above embodiment, the coil spring 50 passes through through holes 61a and 71b provided in the heat-responsive member 60 and the engaging member 70, respectively, which will be described later. However, the heat-responsive member and the engaging member do not necessarily have through holes through which the coil spring passes. In this case, the coil spring may be supported by the engaging member. Alternatively, only the engaging member may have through holes, and the coil spring may be passed through these holes and supported by the heat-responsive member.

[0135] In the above embodiment, the connecting terminal 40 is made of an arched leaf spring, the central portion in the direction intersecting the direction of movement is spaced further apart from the pair of lead terminals 30 than the ends. However, the connecting terminal does not have to be made of an arched leaf spring, as long as it has a configuration that allows it to contact the pair of lead terminals.

[0136] In the above embodiment, the manually resettable thermal protector 1 has a retaining plate 45. However, the manually resettable thermal protector does not necessarily have to have a retaining plate.

[0137] The present invention can be used in a manually resettable thermal protector that shuts off an electrical circuit in response to heat generation and can be manually restored after the electrical circuit has been shut off.

[0138] 1 Manual reset type thermal protector 10 Fixed side case 11 Bottom of fixed side case 11a Opening at the bottom of the case 12 Heat transfer plate 15 Main body of fixed side case 16 Wall of fixed side case 16a Through hole 16b Columnar part 16c Stopper 17 Connecting part 17a Connecting plate part 17b Fixed side spacer part 17c Through hole 18 Guide part 20 Movable side case 21 Top plate of movable side 21a Notch part 21b Through hole in top plate 22 Side wall of movable side 23 Engaged part 23a Engaged surface 30 Lead terminal 31 One end 31a Through hole in lead terminal 32 Other end 40 Connection terminal 41 Center part in the longitudinal direction 41a Terminal protrusion 42 Connection part 42a Terminal contact part 45 Retaining plate 45a Notch 50 Coil spring 60 Thermally responsive member 61 Bottom of thermally responsive member 61a Through hole 62 Wall of thermally responsive member 70 Engaging member 71 Bottom of engaging member 71a Support of engaging member 71b Through hole 72 Wall of engaging member 73 Claw portion P Axis

Claims

1. A manually resettable thermal protector that shuts off an electrical circuit in response to heat generation and can be manually reset after the electrical circuit is shut off, comprising: a pair of lead terminals arranged with their ends spaced apart and constituting a part of the electrical circuit; a movable body that is movable relative to the pair of lead terminals; a connecting terminal disposed between the pair of lead terminals and the movable body; a coil spring that applies a biasing force to the connecting terminal such that it separates the connecting terminal from the pair of lead terminals; a thermally responsive member that deforms in a direction intersecting the direction of movement of the movable body when heated above a predetermined temperature; and an engaging member that holds the movable body so as to press the connecting terminal against the pair of lead terminals against the biasing force of the coil spring, and engages with the movable body at multiple positions such that the holding of the movable body is released by the deformation of the thermally responsive member.

2. A manually reset thermal protector according to claim 1, wherein the plurality of positions in which the engaging member engages with the moving body include positions on both sides of the central portion of the moving body when viewed in the direction of movement of the moving body.

3. A manually reset thermal protector according to claim 1 or 2, further comprising a fixed-side case that fixes the pair of lead terminals with their ends spaced apart and supports the coil spring, the heat-responsive member and the engaging member, wherein the movable body is a movable-side case that is movable relative to the fixed-side case.

4. A manually reset thermal protector according to claim 3, wherein the moving side case comprises: a moving side top plate portion covering the pair of lead terminals; a pair of moving side wall portions extending in the direction of movement opposite to each other from both ends of the moving side top plate portion; and a pair of engaged portions provided on the pair of moving side wall portions, the engaging member having a pair of claw portions that engage with the pair of engaged portions, and the heat-responsive member undergoes deformation that displaces the pair of claw portions when heated to a predetermined temperature or higher, thereby releasing the engagement with the pair of engaged portions.

5. A manually reset thermal protector according to claim 4, wherein the thermal-responsive member comprises: a plate-shaped thermal-responsive member bottom supported by the fixed-side case; and a pair of thermal-responsive member wall portions extending from both ends of the thermal-responsive member bottom so as to face each other in the thickness direction of the thermal-responsive member bottom, and deforming in a direction intersecting the direction of movement by heat above a predetermined temperature; the engaging member comprises: a plate-shaped engaging member bottom having an engaging member support portion supported by the fixed-side case; and a pair of engaging member wall portions extending from both ends of the engaging member bottom so as to face each other in the thickness direction of the engaging member bottom; the pair of claw portions are provided at the tips of the pair of engaging member wall portions; and the pair of thermal-responsive member wall portions are positioned in a direction intersecting the direction of movement with respect to the pair of engaging member wall portions so as to be able to release the engagement between the pair of claw portions and the pair of engaged portions by the deformation; 6. A manually reset type thermal protector according to claim 5, wherein the pair of engaged portions of the movable side case are provided on the device-inward side of the pair of movable side walls, the engaging member is arranged such that the pair of engaging member walls extend along the pair of thermal-responsive member walls at a position inward of the device relative to the pair of thermal-responsive member walls of the thermal-responsive member, and the bottom of the engaging member overlaps in the thickness direction at a position inward of the device relative to the bottom of the thermal-responsive member, and the pair of claws of the engaging member extend outward of the device and engage with the pair of engaged portions of the movable side case.

7. A manually reset thermal protector according to claim 6, wherein the fixed-side case has a fixed-side case bottom that supports the heat-responsive member and the engaging member, and the coil spring is supported by the fixed-side case bottom and penetrates the bottom of the heat-responsive member and the bottom of the engaging member in the thickness direction, respectively, to support the connection terminal.

8. A manually reset thermal protector according to claim 7, wherein the fixed-side case has a fixed-side holding portion located between the bottom of the engaging member of the engaging member and the pair of lead terminals, and the fixed-side holding portion has a through hole through which the coil spring passes.

9. A manually reset thermal protector according to any one of claims 1 to 8, wherein the connection terminal is composed of an arched leaf spring whose central portion in a direction intersecting the direction of movement is spaced further apart from the ends than the pair of lead terminals.

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