Thermal Protector

Abstract

This thermal protector comprises: a base member and a cover member that are made of resin; a stationary contact point and a movable contact point that are provided in a housing space; a stationary member that is provided with the stationary contact point; a movable member that is provided with the movable contact point; and a heat-responsive element that is housed in the housing space and, by being deformed due to heat, causes a force to act on the movable member in a direction such that the movable contact point separates from the stationary contact point. The base member has a protrusion that is provided to the base member and protrudes from a surface of the base member. The cover member has a through-hole that is formed at a position that corresponds to the protrusion and is formed so as to penetrate the cover member. The base member and the cover member are fixed to each other by having the protrusion be inserted through the through-hole and protrude to the outside of the cover member, and having a heat crimp formed by heat crimping in the protruding portion.

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to a thermal protector. [Background technology]

[0002] A thermal protector houses a thermally responsive element and a normally closed contact mechanism inside an insulating resin case member. When abnormal heat is detected, the thermally responsive element operates, opening the contact mechanism to interrupt the current. The case member is constructed, for example, by joining a cover member and a base member. In such a conventional configuration, the cover member and the base member are joined together by ultrasonic welding around the peripheries of the cover member and the base member.

[0003] However, in the case of ultrasonic welding, for example, high-frequency vibrations can cause wear between the cover member and the base member, generating wear debris inside the case member. If the wear debris inside the case member gets between the contacts, it is more likely to cause poor resistance or poor conductivity, which can result in a decrease in the reliability of the thermal protector. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-100054 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, a thermal protector that can improve reliability is provided. [Means for solving the problem]

[0006] A thermal protector according to an embodiment of the present invention includes a base member made of an electrically insulating and thermoplastic resin, a cover member made of an electrically insulating resin and attached to the base member to form a storage space between the base member and the cover member, a fixed contact and a movable contact provided within the storage space, a fixed member provided with the fixed contact and fixed to the base member, a movable member provided with the movable contact, configured to be deformable within the storage space and to apply a force to the movable contact in a direction toward contact with the fixed contact, and a thermally responsive element housed in the storage space and deforming in response to heat to apply a force to the movable member in a direction toward which the movable contact moves away from the fixed contact. The base member has a protrusion provided on the base member and protruding from a surface of the base member. The cover member has a through-hole formed through the cover member at a position corresponding to the protrusion. The base member and the cover member are fixed to each other by the protrusion passing through the through-hole and protruding outward from the cover member, and a thermal caulking portion formed in the protruding portion. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an exploded perspective view showing a switch assembly, a first case, and a second case that constitute a thermal protector according to an embodiment; [Figure 2] FIG. 1 is a perspective view of a switch assembly of a thermal protector according to an embodiment, viewed from the base member side; [Figure 3] FIG. 1 is a perspective view of a switch assembly of a thermal protector according to an embodiment, viewed from the cover member side; [Figure 4] FIG. 1 is a perspective view of a switch assembly of a thermal protector according to an embodiment, seen from the cover member side, illustrating a state before a thermal caulking portion is formed on a protrusion. [Figure 5] FIG. 1 is an exploded perspective view of an example switch assembly of a thermal protector according to one embodiment. [Figure 6] FIG. 1 is a plan view showing a switch assembly from the cover member side of an example of a thermal protector according to an embodiment; [Figure 7] FIG. 10 is a plan view illustrating an example of a thermal protector according to an embodiment, in a state during assembly of a switch assembly, before a cover member, a backing member, and a clip are attached to a base member. [Figure 8] FIG. 7 is a cross-sectional view of an example of a thermal protector according to an embodiment taken along line X8-X8 in FIG. 6. [Figure 9] FIG. 7 is a cross-sectional view of an example of a thermal protector according to an embodiment taken along line X9-X9 in FIG. 6. [Figure 10] 10 is a cross-sectional view showing an example of a thermal protector according to an embodiment, in which the thermally responsive element is deformed from the state shown in FIG. 9 and the fixed contact and the movable contact are opened. [Figure 11] FIG. 11 is an enlarged cross-sectional view of an example of a thermal protector according to an embodiment of the present invention, showing a portion X11 of FIG. [Figure 12] FIG. 1 is a cross-sectional view of an example of a thermal protector according to an embodiment, in which a second case and a first case are partially cut away to show how a switch assembly is housed. [Figure 13] FIG. 13 is an enlarged cross-sectional view of a portion of a thermal protector according to an embodiment taken along line X13-X13 in FIG. 12. [Figure 14] FIG. 14 is an enlarged cross-sectional view of a portion of a thermal protector according to an embodiment taken along line X14-X14 in FIG. 12. [Figure 15] FIG. 13 is an enlarged cross-sectional view of an example of a thermal protector according to an embodiment of the present invention, showing a portion X15 in FIG. 12. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment will be described below with reference to the drawings. The thermal protector of the present invention can be applied, for example, to a three-phase motor as a protected object. The thermal protector of the present invention is attached to the protected object and has the function of detecting abnormal heat generation in the protected object and cutting off the current to the protected object. The thermal protector of the present invention can protect, for example, a three-phase motor. In this case, the thermal protector is connected to all windings on the neutral side of a star-connected three-phase motor. When the thermal protector detects abnormal heat generation in the three-phase motor, it cuts off all windings on the neutral side. The thermal protector of the present invention can also be applied to a single-phase motor, and can also be applied to thermal protectors that protect devices other than motors.

[0009] As shown in FIG. 1 , the thermal protector 1 of this embodiment includes a second case 2, a first case 3, and a switch assembly 10. The switch assembly 10 is a main component of the thermal protector 1 and has the function of interrupting current when abnormal heat generation is detected. As shown in FIGS. 2 and 3 , the switch assembly 10 is generally rectangular, for example, in the shape of a rectangular plate. In the following description, the longitudinal direction of the switch assembly 10 will be referred to as the longitudinal direction of the switch assembly 10 and the thermal protector 1, and the direction perpendicular to the longitudinal direction will be referred to as the width direction of the switch assembly 10 and the thermal protector 1. The direction perpendicular to both the longitudinal direction and the width direction will be referred to as the height direction or thickness direction of the switch assembly 10 and the thermal protector 1.

[0010] As shown in Fig. 5 etc., the switch assembly 10 includes a fixed contact 12, a movable contact 13, a fixed member 20, a movable member 30, a thermally responsive element 40, a base member 50, a cover member 60, a clip 70, and a backing member 80. The base member 50 and the cover member 60 form a case member that serves as the outer shell of the switch assembly 10. The base member 50 and the cover member 60 are combined with each other to form the outer shell of the switch assembly 10, and also form an accommodating space 11 therein, as shown in Figs.

[0011] 5 and other figures, the switch assembly 10 has two fixed contacts 12, two movable contacts 13, two fixed members 20, and one movable member 30. The fixed contacts 12, the movable contact 13, a portion of the fixed member 20, a portion of the movable member 30, and the thermally responsive element 40 are arranged in an accommodating space 11. The fixed contacts 12, the movable contact 13, the fixed member 20, and the movable member 30 form a contact mechanism that is normally closed and opens when the thermally responsive element 40 is activated. The fixed contacts 12 and the movable contact 13 can be made of an alloy containing a metal with low electrical resistance, such as gold, silver, or copper.

[0012] The fixing member 20 is fixed to the base member 50. The fixing member 20 is made of a long, conductive metal plate. The fixing member 20 can be made of a metal plate such as steel, copper, or stainless steel. As shown in FIG. 9, a portion of the fixing member 20 is embedded in the base member 50 by insert molding. As shown in FIG. 5, the two fixing members 20 are arranged parallel to each other and spaced apart from each other, and are embedded in the base member 50, thereby being electrically insulated from each other.

[0013] As shown in FIG. 9 and other figures, one end of the fixing member 20 is exposed to the outside from the base member 50. The portion of the fixing member 20 exposed to the outside of the base member 50 may be referred to as the fixing portion side connection portion 21. A power line connected to the device to be protected is connected to the fixing portion side connection portion 21. In the present embodiment, two-phase power lines of the three-phase power lines connected to the device to be protected are connected to each of the fixing portion side connection portions 21 of the two fixing members 20. The other end 22 of the fixing member 20 is partially exposed within the accommodation space 11. The fixed contact 12 is provided at the end 22 opposite the fixing portion side connection portion 21 and is exposed within the accommodation space 11.

[0014] 9 and other figures, the movable member 30 is sandwiched between the base member 50 and the cover member 60 and supported in a cantilevered manner. Of the portion of the movable member 30 other than the portion sandwiched between the base member 50 and the cover member 60, a portion is exposed to the outside of the base member 50 and the cover member 60, and the other portion is exposed within the accommodation space 11.

[0015] The movable member 30 is preferably made of a spring alloy material that has relatively low electrical resistance and high heat resistance. Examples of materials that can be used for the movable member 30 include beryllium copper alloy, titanium copper alloy, and Corson copper alloy. As shown in FIGS. 5 and 7, the movable member 30 is made of, for example, a metal plate with a portion split into two. The longitudinal direction of the movable member 30 coincides with the longitudinal direction of the switch assembly 10, and the width direction of the movable member 30 coincides with the width direction of the switch assembly 10. The movable member 30 has a movable-part-side connecting portion 31, a clamped portion 32, a fulcrum portion 33, two arm portions 34, and two or more (three in this case) insertion holes 35.

[0016] 7, 8, and 9, the movable part side connection part 31 is provided at one of the two ends of the movable part 30 that is not bifurcated, and is exposed to the outside of the base member 50 and the cover member 60. A power line connected to the device to be protected is connected to the movable part side connection part 31. In the present embodiment, one phase of a three-phase power line connected to the device to be protected is connected to the movable part side connection part 31.

[0017] The clamped portion 32 is provided between the movable portion-side connecting portion 31 and the arm portion 34. The clamped portion 32 is a portion that comes into contact with the base member 50 or the cover member 60 when the movable member 30 is sandwiched between the base member 50 and the cover member 60, i.e., a portion that receives a pressing force from the base member 50 and the cover member 60. The clamped portion 32 can be formed in a rectangular shape, for example, a rectangular shape that is long in the width direction of the switch assembly 10.

[0018] The fulcrum portion 33 is the boundary between the clamped portion 32 and the arm portion 34. The arm portion 34 is the portion of the movable member 30 that is exposed within the accommodation space 11, in this case, the base point of the bifurcated portion. The arm portion 34 is configured to be deformable within the accommodation space 11 with the fulcrum portion 33 as a fulcrum, i.e., to be able to swing in the thickness direction.

[0019] The movable contact 13 is provided near the tip of the bifurcated portion of the movable member 30, i.e., near the tip of the arm portion 34, and at a position facing the corresponding fixed contact 12. The movable member 30 is formed in a curved shape so as to bulge toward the cover member 60 when no external force is acting on the movable member 30, i.e., when the movable member 30 is not assembled into the switch assembly 10. When the movable member 30 is assembled into the switch assembly 10, the movable contact 13 is brought into contact with the fixed contact 12, and the arm portion 34 is elastically deformed around the fulcrum portion 33, and the movable member 30 is fixed between the base member 50 and the cover member 60. The elastic force, i.e., the restoring force, of the movable member 30 applies a force to the movable contact 13 in a direction pressing the movable contact 13 against the fixed contact 12.

[0020] When the arm portion 34 is not subjected to an external force other than the resistance force from the fixed contact 12, the elastic force of the movable member 30 presses the movable contact 13 against the fixed contact 12. In this case, the thermal protector 1 is in a closed state, i.e., the fixed-portion-side connection portion 21 of the fixed member 20 and the connection portion 31 of the movable member 30 are electrically connected. In contrast, when the arm portion 34 is subjected to an external force in a direction that moves the movable contact 13 away from the fixed contact 12, i.e., a force in the upward direction in the plane of the paper in FIG. 9 , which is greater than the elastic force of the movable member 30, the arm portion 34 deforms in a direction that moves the movable contact 13 away from the fixed contact 12, resulting in the movable contact 13 being separated from the fixed contact 12. In this case, the thermal protector 1 is in an open state, i.e., the fixed-portion-side connection portion 21 of the fixed member 20 and the connection portion 31 of the movable member 30 are electrically disconnected.

[0021] As shown in Figs. 5 and 8, the insertion hole 35 is formed so as to penetrate the clamped portion 32 in the thickness direction. The insertion hole 35 is, for example, a circular, rectangular, or elliptical hole. In this embodiment, the movable member 30 has three insertion holes 35. The three insertion holes 35 are arranged, for example, in a straight line along the longitudinal direction of the clamped portion 32, i.e., the width direction of the movable member 30. As shown in Fig. 7, one of the three insertion holes 35 is provided on the center line C of the movable member 30 in the width direction.

[0022] The thermally responsive element 40 is housed in the housing space 11, and as shown in FIG. 8 etc., is provided between the fixed member 20 and the movable member 30 when viewed in the thickness direction of the switch assembly 10. The thermally responsive element 40 is made of a bimetal and has a rectangular plate shape. The thermally responsive element 40 is disposed in the housing space 11 without being fixed. The thermally responsive element 40 deforms when exposed to heat, and applies a force to the movable member 30 in a direction that moves the movable contact 13 away from the fixed contact 12.

[0023] When not deforming, the thermally responsive element 40 has a vertex 41 near the center of the thermally responsive element 40, and is curved in an arched shape or a spherically curved dish shape from the vertex 41 toward both ends of the switch assembly 10 in the longitudinal direction, as shown in FIG. 9. When the thermally responsive element 40 receives a predetermined amount of heat, it deforms and reverses its curvature as shown in FIG. 10. Then, a side portion 42 of the thermally responsive element 40 at one end of the switch assembly 10 in the longitudinal direction comes into contact with the vicinity of the fulcrum portion 33 of the movable member 30. Furthermore, a side portion 43 of the thermally responsive element 40 at the other end of the switch assembly 10 in the longitudinal direction comes into contact with the arm portion 34. A protrusion may be provided at the position of the arm portion 34 where the side portion 43 comes into contact.

[0024] In the following description, of the peripheral sides 42, 43, and 44 of the thermally actuated element 40, the side 42 that comes into contact with the vicinity of the fulcrum portion 33 when deforming may be referred to as the rear side 42. Also, of the peripheral sides 42, 43, and 44 of the thermally actuated element 40, the side 43 that comes into contact with the arm portion 34 when deforming may be referred to as the front side 43. And, of the peripheral sides 42, 43, and 44 of the thermally actuated element 40, the side sandwiched between the rear side 42 and the front side 43 may be referred to as the side side 44.

[0025] 11, the vicinity of fulcrum portion 33 is sandwiched between base member 50 and cover member 60, so it is difficult to deform even when subjected to force from thermally responsive element 40. Therefore, when thermally responsive element 40 deforms, it swings around side portion 42 that is in contact with the vicinity of fulcrum portion 33 as a fulcrum. Then, side portion 43 of thermally responsive element 40 that is in contact with arm portion 34 lifts arm portion 34 toward cover member 60. This separates movable contact 13 from fixed contact 12, and thermal protector 1 switches to an open state, i.e., a state in which power supply to the device to be protected is cut off.

[0026] 11, the cover member 60 extends further toward the tip side of the movable member 30, i.e., toward the arm portion 34 side, than the base member 50 at the portion where the movable member 30 is sandwiched between the cover member 60 and the base member 50, i.e., the portion in contact with the clamped portion 32. In other words, the rear edge portion 42 of the thermally responsive element 40 and the portion of the cover member 60 in contact with the movable member 30 overlap in a plan view in area A of FIG.

[0027] With this configuration, when the thermally responsive element 40 deforms and the rear edge portion 42 of the thermally responsive element 40 comes into contact with the movable member 30, the cover member 60 can receive the force applied to the movable member 30 from the rear edge portion 42 at the area A of the cover member 60. Therefore, even if the boundary portion 62 between the portion of the cover member 60 that contacts the movable member 30 and the portion that does not contact the movable member 30 has an angular shape, it is possible to prevent a large shear force from acting on the portion of the movable member 30 that contacts the boundary portion 62, and as a result, deformation or breakage of the movable member 30 can be prevented.

[0028] The base member 50 is made of, for example, an electrically insulating and thermoplastic resin. The base member 50 is preferably made of, for example, a material that is heat resistant and electrically insulating and has good adhesive properties for epoxy adhesives. The base member 50 can be made of, for example, polyphenylene sulfide (PPS) mixed with approximately 30% to 40% glass fiber. The base member 50 is configured, for example, in the shape of a rectangular plate overall.

[0029] 5 and 7 to 9, the base member 50 is configured to have a recessed portion 51, a support portion 52, multiple protrusions 531, 532, and 533, a contact hole 54, a rear wall portion 55, a side wall portion 56, and an intermediate wall portion 57. The recessed portion 51, the support portion 52, the multiple protrusions 531, 532, and 533, the contact hole 54, the rear wall portion 55, the side wall portion 56, and the intermediate wall portion 57 are configured integrally by resin molding. The protrusions 531 and 533 are provided on one side of the base member 50 in the longitudinal direction in a plan view, and the protrusion 532 is provided on the other side of the base member 50 in the longitudinal direction.

[0030] The recessed portion 51 is a portion formed by recessing the surface of the base member 50 facing the cover member 60 into the recessed portion 51. The recessed portion 51 is a portion that forms the accommodation space 11 when the cover member 60 is attached to the base member 50. The support portion 52 has the function of supporting the thermally responsive element 40. The support portion 52 is provided near the center of the width direction of the base member 50 within the recessed portion 51, and protrudes in a cylindrical shape from the bottom portion of the recessed portion 51. In this case, the thermally responsive element 40 is only supported by the support portion 52, and is not subjected to pressing force or biasing force from other members.

[0031] The base member 50 has five protrusions 531, 532, and 533. The protrusions 531, 532, and 533 are formed to protrude from the surfaces 501 and 502 of the base member 50. The four protrusions 531, 531, 532, and 532 are provided near the corners of the base member 50, respectively. The remaining protrusion 533 is provided on a line connecting two protrusions 531, 531 lined up in the width direction and at an intermediate position between the two protrusions 531, 531. In this embodiment, the height dimension of the protrusions 531 and 532 provided near the corners is approximately equal to the thickness dimension of the base member 50 excluding the protrusions 531 and 532.

[0032] Before the base member 50 and the cover member 60 are joined, each of the protrusions 531, 532, and 533 has a cylindrical rod shape, as shown in FIGS. 4 and 5. After the base member 50 and the cover member 60 are joined, thermally crimped portions 531a, 532a, and 533a are formed at the tip of each of the protrusions 531, 532, and 533, as shown in FIGS. 3, 8, and 9. The thermally crimped portions 531a, 532a, and 533a are formed by heating and softening the portions of each of the protrusions 531, 532, and 533 exposed to the outside of the cover member 60, and then crushing them in that state, a process known as thermal crimping. The outer diameters of the thermally crimped portions 531a, 532a, and 533a are larger than the inner diameters of the through-holes 611, 612, and 613 of the cover member 60.

[0033] The base member 50 and the cover member 60 are formed to have a rectangular shape, for example, a rectangular shape, as a whole in a plan view. The thermal crimping portions 531a, 532a are provided at least at the corners of the base member 50 and the cover member 60. In the present embodiment, a thermal crimping portion 533a is further provided between the two thermal crimping portions 531a.

[0034] As shown in Figures 5, 7 and 9, two contact holes 54 are provided in the recess 51. As shown in Figure 9 and other figures, the contact holes 54 are formed in a circular shape penetrating the bottom of the recess 51. The two contact holes 54 are arranged side by side in the width direction of the base member 50 in the recess 51. The two contact holes 54 are provided on the opposite side in the longitudinal direction of the base member 50 to the three protrusions 531, 532, 533 that are arranged side by side in the width direction of the base member 50. The fixed contacts 12 provided in the fixed member 20 are exposed into the accommodation space 11 from the contact holes 54.

[0035] 5 and 7, the rear wall 55, the side wall 56, and the intermediate wall 57 function to determine the position of the thermally responsive element 40 disposed within the recess 51. The rear wall 55 and the side wall 56 form part of the wall surrounding the recess 51. The rear wall 55 is the wall on the protruding portions 531 and 533 side of the wall surrounding the recess 51.

[0036] The rear wall portion 55 has the function of restricting movement of the thermally responsive element 40 in the longitudinal direction of the base member 50 and toward the protrusions 531 and 533, i.e., movement to the left side of the page in Fig. 7. The rear wall portion 55 contacts one of the sides extending in the width direction of the base member 50 on the outer periphery of the thermally responsive element 40, i.e., the side portion 42 on one side in the longitudinal direction of the base member 50. The rear wall portion 55 is provided over the entire area of ​​the side portion 42 of the thermally responsive element 40.

[0037] The side wall portions 56 function to restrict movement of the base member 50 in the width direction relative to the thermally responsive element 40. Two side wall portions 56 are provided on both sides in the width direction of the recessed portion 51. The side wall portions 56 contact parts of the side portions 44 extending in the longitudinal direction of the base member 50, i.e., the side portions 44 located on both sides in the width direction, of the outer periphery of the thermally responsive element 40. The two side wall portions 56 are provided across parts of the side portions 44 in the width direction of the thermally responsive element 40. The two side wall portions 56 are provided closer to the rear wall portion 55 in the longitudinal direction of the base member 50.

[0038] The intermediate wall portion 57 functions to restrict movement of the thermally responsive element 40 in the longitudinal direction of the base member 50 toward the protrusion 532, i.e., to the right side of the page in FIG. 7 . The intermediate wall portion 57 is provided to rise from the bottom of the recessed portion 51. The intermediate wall portion 57 is provided in the central portion of the recessed portion 51 in the width direction of the base member 50. The intermediate wall portion 57 is provided between the two contact holes 54 and extends in the longitudinal direction of the base member 50. The intermediate wall portion 57 contacts the remaining side portion 43 of the outer periphery of the thermally responsive element 40 that extends in the width direction of the base member 50. The intermediate wall portion 57 also functions to ensure an insulating distance between the fixed contacts 12, 12 of different phases that are arranged in the two contact holes 54.

[0039] When the thermally responsive element 40 is placed inside the recess 51, its longitudinal position relative to the base member 50 is determined by contact with the rear wall 55 and the intermediate wall 57. The widthwise position of the thermally responsive element 40 relative to the base member 50 is determined by contact with the side wall 56. When the thermally responsive element 40 is not deforming, the outer periphery of the thermally responsive element 40 is not in contact with anything other than the rear wall 55, the side wall 56, and the intermediate wall 57.

[0040] The cover member 60 is made of an electrically insulating resin, and is attached to the base member 50 to form a storage space 11 between the cover member 60 and the base member 50. The cover member 60 closes the recessed portion 51 of the base member 50, thereby making the interior of the recessed portion 51 the storage space 11. Like the base member 50, the cover member 60 can be made of polyphenylene sulfide (PPS) mixed with, for example, approximately 30% to 40% glass fiber.

[0041] 5 and other figures, the cover member 60 has a plurality of, for example, five, through-holes 611, 612, 613. Each of the through-holes 611, 612, 613 is formed at a position corresponding to each of the protrusions 531, 532, 533. Each of the through-holes 611, 612, 613 is formed by penetrating the cover member 60 in, for example, a circular shape. The inner diameter of each of the through-holes 611, 612, 613 is slightly larger than the outer diameter of the corresponding protrusion 531, 532, 533.

[0042] The base member 50 and the cover member 60 are joined to each other without using any fastening members such as screws or adhesives, i.e., any members other than the base member 50 and the cover member 60. The base member 50 and the cover member 60 are joined to each other without using ultrasonic welding. When assembling the switch assembly 10, the base member 50 and the cover member 60 are joined to each other as follows.

[0043] First, the thermally responsive element 40 is placed on the support portion 52 in the recess portion 51 of the base member 50. Next, the movable member 30 is placed on the base member 50 with the three protrusions 531, 533 inserted into the insertion hole portion 35 of the movable member 30. Next, the protrusions 531, 532, 533 are inserted into the corresponding through-holes 611, 612, 612 of the cover member 60, and the cover member 60 and the base member 50 are combined.

[0044] At this time, as shown in FIG. 4 , the tip of each of the protrusions 531, 532, and 533 protrudes from each of the through-holes 611, 612, and 612 to the outside of the cover member 60. Then, the portions of each of the protrusions 531, 532, and 533 that protrude to the outside of the cover member 60 are thermally crimped. This thermal crimping causes the tip of each of the protrusions 531, 532, and 533 to be crushed in a softened state, forming thermally crimped portions 531a, 532a, and 533a. The thermally crimped portions 531a, 532a, and 533a are engaged with the through-holes 611, 612, and 613, thereby fixing the base member 50 and the cover member 60 to each other. This thermal crimping does not use high-frequency vibration, unlike ultrasonic welding or the like. Therefore, vibrations that cause the generation of wear particles during ultrasonic welding are not applied to the base member 50 and the cover member 60, and the generation of wear particles in the accommodation space 11 can be suppressed.

[0045] The clip 70 is attached to the long sides of the base member 50 and the cover member 60. The clip 70 holds the base member 50 and the cover member 60 by clamping them from the outside. The clip 70 is formed by bending a metal plate such as a spring plate. The clip 70 applies a force in a direction that brings the base member 50 and the cover member 60 closer to each other, thereby preventing the base member 50 and the cover member 60 from separating from each other.

[0046] 6, clip 70 is provided near the center of the base member 50 and cover member 60 in the longitudinal direction when viewed in a plan view of switch assembly 10. Clip 70 is located between protrusions 531 and 533 and protrusion 532 in the longitudinal direction of switch assembly 10.

[0047] As shown in FIG. 5 , the base member 50 has a base portion-side receiving portion 58. The base portion-side receiving portion 58 is a portion formed by recessing the side surface of the base member 50 by approximately the thickness of the clip 70. The cover member 60 has a cover portion-side receiving portion 63. The cover portion-side receiving portion 63 is a portion formed by recessing the side surface of the cover member 60 by approximately the thickness of the clip 70. When the base member 50 and the cover member 60 are combined, the base portion-side receiving portion 58 and the cover portion-side receiving portion 63 are substantially flush with each other. The clip 70 is fitted into the base portion-side receiving portion 58 and the cover portion-side receiving portion 63.

[0048] 8 to 10, the backing member 80 is embedded in the cover member 60 by insert molding. The backing member 80 is provided on the opposite side of the movable member 30 from the thermally responsive element 40. The backing member 80 has the function of dissipating heat generated in the movable contact 13 and the movable member 30 when the switch assembly 10 is opened. The backing member 80 can be made of a metal plate with high thermal conductivity, such as a stainless steel plate or a copper plate.

[0049] The backing member 80 has a contact portion 81. The contact portion 81 is provided at a position overlapping the movable contact 13 in a plan view, and is exposed within the accommodation space 11. The movable member 30 comes into contact with the contact portion 81 of the backing member 80 when the movable member 30 is deformed in a direction in which the movable contact 13 moves away from the fixed contact 12. At this time, heat generated in the movable contact 13 and the movable member 30 is dissipated to the cover member 60 via the backing member 80.

[0050] As shown in FIGS. 12 and 13 , a power line 91 is electrically and physically connected to each connection portion 21, 31 of the switch assembly 10 by welding or the like. As shown in FIGS. 1 , 12 , and 13 , the thermal protector 1 is configured by inserting a first case 3 into a second case 2, and then inserting the switch assembly 10 into the first case 3. The second case 2 can be configured of a metal such as steel plate, stainless steel, or copper, and is configured in a box shape with a second opening 2a on one side of the cube. The second case 2 may be plated, for example, to improve mechanical strength and thermal conductivity. The second case 2 can also be configured of a high-strength resin material such as so-called engineering plastic.

[0051] The first case 3 is configured in a box shape with a first opening 3a on one side of a cube. The first case 3 is made of an electrically insulating resin and houses the switch assembly 10 inside. The first case 3 can be made of polyethylene terephthalate (PBT) mixed with approximately 30% to 40% glass fiber, for example.

[0052] The thermal protector 1 can be assembled, for example, as follows: First, the switch assembly 10, with the power lines 91 connected to the connection portions 21, 31, is inserted into the first case 3. Next, the first case 3 containing the switch assembly 10 is inserted into the second case 2. In this way, the thermal protector 1 is assembled.

[0053] 12 to 15, the thermal protector 1 further includes an insulating member 4, a first filler 5, and a second filler 6. The insulating member 4 is made of an electrically insulating resin material. The insulating member 4 is inserted between adjacent connection portions 21, 31 to restrict movement of the power lines 91 connected to the connection portions 21, 31 and ensure insulation between the power lines 91.

[0054] The insulating member 4 can be made of, for example, the same material as the first case 3, such as polyethylene terephthalate (PBT) mixed with approximately 30% to 40% glass fiber. The insulating member 4 integrally has two partition walls 4a and a connection part 4b. The two partition walls 4a are arranged parallel to each other and face each other in plate-like portions extending in the longitudinal direction of the switch assembly 10. The partition wall 4a is arranged between the fixed part side connection part 21 and the movable part side connection part 31.

[0055] The connecting portion 4b connects the two partition walls 4a. The connecting portion 4b is formed in a plate shape having a surface perpendicular to the partition walls 4a. The connecting portion 4b is disposed on one side in the thickness direction of the switch assembly 10, in this case, closer to the base member 50 side.

[0056] As shown in Figure 6, the switch assembly 10 further has two insertion portions 14. The insertion portions 14 are provided corresponding to the partition wall portions 4a, and are formed by recessing the base member 50 and the cover member 60. When the insulating member 4 is attached to the switch assembly 10, the tip portions of the partition wall portions 4a fit into the insertion portions 14. This defines the attachment position of the insulating member 4 relative to the switch assembly 10.

[0057] Of the longitudinal ends of the insulating member 4, the end located on the outer side is not covered by the first filler 5 and is exposed from the first filler 5 and the first case 3. Of the longitudinal ends of the insulating member 4, the end located on the outer side is formed asymmetrically when viewed in the thickness direction of the switch assembly 10. The insulating member 4 has an asymmetric portion 4c. The asymmetric portion 4c can be formed, for example, by a cutout portion formed by cutting off the corner of the partition portion 4a on the outer side. When handling the switch assembly 10, workers, assembly equipment, etc. can identify the front and back of the switch assembly 10 by checking the position of the asymmetric portion 4c of the insulating member 4.

[0058] 12 and 13, the first filler 5 is filled between the switch assembly 10 and the first case 3. The first filler 5 is an electrically insulating material, and may be a thermosetting resin such as an epoxy adhesive. After the switch assembly 10 and the insulating member 4 are inserted into the first case 3, the first filler 5 is filled into the first case 3 through the first opening 3a of the first case 3.

[0059] In FIGS. 12 and 13 , the second filler 6 is indicated by dashed hatching perpendicular to the hatching of the first filler 5. The second filler 6 is present within the second case 2 and fills the portion of the second case 2 that contacts the first filler 5 near the second opening 2a of the second case 2. The second filler 6 is an electrically insulating material and, like the first filler 5, may be a thermosetting resin such as an epoxy adhesive. After the first case 3 housing the switch assembly 10 and the insulating member 4 is inserted into the second case 2, the second filler 6 is filled into the second case 2 through the second opening 2a of the second case 2. The second filler 6 is filled into the second case 2 through the second opening 2a to close the second opening 2a and secure the first case 3 within the second case 2. Note that, for example, a configuration may be adopted in which the gap between the first case 3 and the second case 2 is enlarged and filled with the second filler 6.

[0060] 2 to 4, 12, and 15, the switch assembly 10 has a step portion 15. The step portion 15 is a step-shaped portion provided around the first opening 3a side of the first case 3 of the switch assembly 10, and the step portion 15 with which the first filler 5 comes into contact is provided across the base member 50 and the cover member 60. As shown in FIG. 15, the step portion 15 has the function of suppressing the progression of cracks V in the first filler 5 that have started from the first opening 3a side and peeling of the adhesive surface. For example, as shown in FIG. 15, the progression of a crack V in the first filler 5 that has started from the first opening 3a side is stopped by hitting the step portion 15.

[0061] The thermal protector 1 of this embodiment includes a base member 50, a cover member 60, a fixed contact 12, a movable contact 13, a fixed member 20, a movable member 30, and a thermally responsive element 40. The base member 50 is made of an electrically insulating and thermoplastic resin. The cover member 60 is made of an electrically insulating resin and is attached to the base member 50 to form an accommodation space 11 between the base member 50 and the cover member 60. The fixed contact 12 and the movable contact 13 are located within the accommodation space 11. The fixed member 20 is provided with the fixed contact 12 and is fixed to the base member 50. The movable member 30 is provided with a movable contact, is configured to be deformable within the accommodation space 11, and applies a force to the movable contact 13 in a direction to contact the fixed contact 12. The thermally responsive element 40 is housed in the accommodation space 11 and, by deforming in response to heat, applies a force to the movable member 30 in a direction to move the movable contact 13 away from the fixed contact 12.

[0062] The base member 50 has protrusions 531, 532, and 533. The protrusions 531, 532, and 533 are provided on the base member 50 and protrude from surfaces 501 and 502 of the base member 50. The cover member 60 has through-holes 611, 612, and 613. The through-holes 611, 612, and 613 are formed at positions corresponding to the protrusions 531, 532, and 533, and penetrate the cover member 60. The base member 50 and the cover member 60 are fixed to each other by the protrusions 531, 532, and 533 passing through the through-holes 611, 612, and 613 and protruding to the outside of the cover member 60, and by forming thermally caulked portions 531a, 532a, and 533a that are thermally caulked to the protruding portions.

[0063] This allows the base member 50 and the cover member 60 to be joined to each other without using ultrasonic welding. Therefore, vibrations that cause wear particles to be generated during ultrasonic welding are not applied to the base member 50 and the cover member 60, thereby preventing wear particles from being generated in the housing space 11. Furthermore, wear particles generated in the housing space 11 are prevented from entering between the contacts 12, 13, reducing the occurrence of resistance defects, conduction defects, and the like caused by wear particles, and as a result, the reliability of the thermal protector 1 can be improved.

[0064] Therefore, the thermal protector 1 further includes a clip 70. The clip 70 is attached to the long sides of the base member 50 and the cover member 60, and holds the base member 50 and the cover member 60 by clamping them from the outside. This allows the base member 50 and the cover member 60 to be more securely attached to each other, even when the base member 50 and the cover member 60 are joined using partial thermal caulking. This prevents a gap from forming between the base member 50 and the cover member 60 and allowing foreign matter, the first filler material 5, etc. to enter the housing space 11 through the gap. As a result, the reliability of the thermal protector 1 can be further improved.

[0065] The movable member 30 has two or more insertion holes 35. In the present embodiment, the movable member 30 has three insertion holes 35. The insertion holes 35 are formed in the clamped portion 32, which is the portion sandwiched between the base member 50 and the cover member 60, and penetrate the movable member 30 in the thickness direction. Each of the protrusions 531, 532, and 533 is inserted into the corresponding insertion hole 35.

[0066] This allows the movable member 30 to be incorporated into the switch assembly 10 without fixing the movable member 30 to the base member 50 or the cover member 60. In other words, this configuration allows the movable member 30 to be fixed between the base member 50 and the cover member 60 in the same process as the process of joining the base member 50 and the cover member 60. Therefore, the assembly process of the switch assembly 10 can be simplified.

[0067] The movable member 30 is supported in a cantilevered manner by being sandwiched between the base member 50 and the cover member 60. As shown in Fig. 11, the portion of the cover member 60 that contacts the clamped portion 32 of the movable member 30 extends beyond the base member 50 by an area A toward the tip end of the movable member 30, i.e., toward the arm portion 34.

[0068] This prevents large shear forces from acting on the part of the movable member 30 that comes into contact with the boundary portion 62 from the rear edge 42 of the thermally responsive element 40, even if the boundary portion 62 of the cover member 60 between the part that comes into contact with the movable member 30 and the part that does not, and as a result, prevents deformation or breakage of the movable member 30.

[0069] The thermal protector 1 further includes a backing member 80. The backing member 80 is made of metal and is provided in the cover member 60 by insert molding. The backing member 80 comes into contact with the movable member 30 when the movable member 30 is deformed in a direction in which the movable contact 13 moves away from the fixed contact 12. When the fixed contact 12 and the movable contact 13 open, heat from the movable contact 13 can be released to the cover member 60 via the backing member 80. This makes it possible to prevent problems such as a change in the spring constant of the movable member 30 due to excessive heat being applied to the movable member 30.

[0070] The thermally responsive element 40 is disposed without being fixed inside the accommodation space 11. This eliminates the need for a process for fixing the thermally responsive element 40 to the base member 50 or the cover member 60, thereby simplifying the assembly process of the switch assembly 10.

[0071] The thermal protector 1 further includes a switch assembly 10, a first case 3, and a first filler 5. The switch assembly 10 is configured by assembling a base member 50, a cover member 60, a fixed contact 12, a movable contact 13, a fixed member 20, a movable member 30, and a thermally responsive element 40. The first case 3 is configured to be able to house the switch assembly 10 and has a first opening 3a into which the switch assembly 10 is inserted. The first filler 5 is filled into the first case 3 through the first opening 3a of the first case 3 and around the switch assembly 10, and the switch assembly 10 has a step 15 at the portion with which the first filler 5 comes into contact.

[0072] 15, a crack V in the first filling material 5 that has started from the first opening 3a side, for example, hits the step 15 and stops its progression. Therefore, the step 15 can suppress the progression of the crack V in the first filling material 5 that has started from the first opening 3a side and the peeling of the adhesive surface. This prevents the crack V from expanding and causing a decrease in insulation performance, thereby improving the reliability of the thermal protector 1.

[0073] The thermal protector 1 further includes a second case 2 and a second filler 6. The second case 2 is configured to be able to house the first case 3 that houses the switch assembly 10, and has a second opening 2a into which the first case 3 is inserted. The second filler 6 is filled into the second case 2 through the second opening 2a to close the second opening 2a and fix the first case 3 within the second case 2.

[0074] According to this, by covering the outside of the first case 3 with the second case 2, even if an external force is applied to the thermal protector 1, the external force is prevented from being directly applied to the first case 3. Furthermore, by fixing the first case 3 within the second case 2 with the second filler 6, even if an external force is applied to the thermal protector 1, it is possible to prevent the first case 3 from moving significantly within the second case 2 and causing violent collisions between the first case 3 and the second case 2. Therefore, according to this configuration, by suppressing deformation of the first case 3 due to the application of an external force to the thermal protector 1, it is possible to suppress changes in the characteristics of the thermal protector due to deformation of the accommodation space 11, and as a result, it is possible to further improve the reliability of the thermal protector 1.

[0075] The above-described embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The present embodiment and its modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

Claims

1. a base member made of an electrically insulating and thermoplastic resin; a cover member made of an electrically insulating resin and attached to the base member to form a storage space between the cover member and the base member; a fixed contact and a movable contact provided in the accommodation space; a fixed member provided with the fixed contact and fixed to the base member; a movable member provided with the movable contact, configured to be deformable within the accommodation space, and applying a force to the movable contact in a direction that causes the movable contact to come into contact with the fixed contact; a thermally responsive element that is accommodated in the accommodation space and deforms in response to heat, thereby applying a force to the movable member in a direction in which the movable contact moves away from the fixed contact, the base member has a protrusion provided on the base member and protruding from a surface of the base member, the cover member has a through-hole formed at a position corresponding to the protrusion and penetrating the cover member, the base member and the cover member are fixed to each other by the protruding portion being passed through the through-hole portion and protruding outward from the cover member, and the outer diameter of the protruding portion being formed larger than the inner diameter of the through-hole portion, and being engaged with the through-hole portion; a clip attached to the long side portions of the base member and the cover member, the clip sandwiching and holding the base member and the cover member from the outside of the base member and the cover member; Thermal protector.

2. a base member made of an electrically insulating and thermoplastic resin; a cover member made of an electrically insulating resin and attached to the base member to form a storage space between the cover member and the base member; a fixed contact and a movable contact provided in the accommodation space; a fixed member provided with the fixed contact and fixed to the base member; a movable member provided with the movable contact, configured to be deformable within the accommodation space, and applying a force to the movable contact in a direction that causes the movable contact to come into contact with the fixed contact; a thermally responsive element that is accommodated in the accommodation space and that deforms in response to heat to apply a force to the movable member in a direction that moves the movable contact away from the fixed contact; a switch assembly including the above components; a first case configured to accommodate the switch assembly and having a first opening into which the switch assembly is inserted; a first filler material filled in the first case through the first opening and around the switch assembly; a second case configured to be able to house the first case housing the switch assembly and having a second opening into which the first case is inserted; a second filler that is filled into the second case through the second opening to close the second opening and fix the first case within the second case, the base member has a protrusion provided on the base member and protruding from a surface of the base member, the cover member has a through-hole formed at a position corresponding to the protrusion and penetrating the cover member, the base member and the cover member are fixed to each other by the protruding portion being passed through the through-hole portion and protruding outward from the cover member, and the outer diameter of the protruding portion being formed larger than the inner diameter of the through-hole portion, and being engaged with the through-hole portion; The switch assembly has a step portion at a portion where the first filler comes into contact. Thermal protector.

3. the movable member has two or more insertion holes formed in a portion sandwiched between the base member and the cover member so as to penetrate the movable member in a thickness direction, The protrusion is inserted into the insertion hole.

3. The thermal protector according to claim 1 or 2.

4. the movable member is sandwiched between the base member and the cover member and supported in a cantilevered manner, a portion of the cover member that contacts the movable member extends further toward the tip end of the movable member than the base member; 3. The thermal protector according to claim 1 or 2.

5. The movable contact may further include a metal backing member that is embedded in the cover member and that comes into contact with the movable contact when the movable contact is deformed in a direction in which the movable contact moves away from the fixed contact.

3. The thermal protector according to claim 1 or 2.

6. The thermally responsive element is disposed in the accommodation space without being fixed.

3. The thermal protector according to claim 1 or 2.

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