WO2011105175A1

WO2011105175A1 - Breaker

Info

Publication number: WO2011105175A1
Application number: PCT/JP2011/051941
Authority: WO
Inventors: 中西義博; 八木孝太
Original assignee: 株式会社小松ライト製作所
Priority date: 2010-02-26
Filing date: 2011-01-31
Publication date: 2011-09-01
Also published as: JPWO2011105175A1; KR20130019370A; EP2541576A1; JP2012238615A; EP2541576B1; CN105304416A; JP2013149632A; EP2541576A4; JP4980495B2; JP5695695B2; HK1178687A1; JP5661145B2; CN102782793A; CN105304416B; JP2013140819A; JP2012084548A; CN102782793B; JP5154708B2

Abstract

Disclosed is a miniature breaker which progressively reduces contact resistance and permits further miniaturisation by appropriately maintaining the contact locations of a fixed contact point and moveable contact point. The breaker is equipped with a fixed contact point (2), a moveable contact point (3), a bimetal (4) and a case (6), where the moveable contact point (3) is equipped with a second elastic member (35) possessing a lower elastic coefficient than a first elastic member (34), and a fixing member (33) disposed between the first elastic member (34) and second elastic member (35) which is fixed by the case (6).

Description

breaker

The present invention relates to a small breaker incorporated in a secondary battery.

Conventionally, a safety device for a secondary battery such as a small nickel-metal hydride battery or a lithium-ion battery mounted on a mobile phone or a notebook personal computer has a PTC thermistor (the resistance value increases rapidly above a certain temperature). Conductive materials) and thermal fuses are used. Each of these protection circuits has a drawback that it is difficult to set a precise temperature with a wide operating temperature bandwidth, or that it cannot be used more than once, so that it is impossible to perform 100% inspection in the manufacturing process. . Therefore, in place of such a conventional protection circuit, there is a demand for a mechanically operated safety device that can set a precise operating temperature and withstand multiple use, and various techniques have been proposed. .

For example, Patent Document 1 discloses a fixed piece having a fixed contact, a movable piece having a movable contact at the tip, and a thermally responsive element that operates the movable piece so that the movable contact is separated from the fixed contact at a predetermined operating temperature. And a small breaker including a PTC element connected to a fixed piece and an insulating flat case for housing them. Patent Document 2 discloses a method for manufacturing a small breaker.

JP 2005-129471 A JP 2002-83523 A

2. Description of the Related Art Secondary batteries used for mobile phones, notebook computers, and the like have been increasingly miniaturized in recent years, and further miniaturization is required for small breakers built into secondary batteries. However, if the component size of a mechanically operated product such as a small breaker falls below a certain value, it is possible to achieve both sufficient completeness and productivity by simply reducing the components and applying them to existing production equipment and manufacturing methods. It becomes difficult. In particular, in the process of positioning the fixed contact provided on the fixed piece of the small breaker and the movable contact provided on the movable piece, the degree of vulnerability to errors during assembly increases as the member size decreases, and the fixed contact And the movable contact are liable to be displaced to a place where the contact position is not appropriate.

Such misalignment of the contacts causes a problem that the contact resistance becomes unstable, which is serious for the safety device of the electric product, and has been an obstacle in reducing the defective rate of the small breaker. In particular, when the size of the movable piece reaches sub-millimeter accuracy, the problems caused by the above-described positional deviation of the contact are prominent in the assembly process of all members including mounting of the thermally responsive element and the movable piece and mounting of the lid member. It becomes. Furthermore, if the handling is rough when assembling the finished small good breaker to the safety device, the contact position of the contact may be adversely affected when the terminal is twisted.

The present invention has been made in order to solve the above-described problems, and by properly maintaining the contact position between the fixed contact and the movable contact, it is possible to further reduce the size while reducing the contact resistance. The purpose is to provide.

In order to achieve the above object, the invention according to claim 1 is a fixed piece having a fixed contact, a movable piece having a movable contact at a tip, and pressing the movable contact against the fixed contact, and a temperature change. In a breaker comprising: a thermal response element that operates the movable piece so that the movable contact is separated from the fixed contact by being deformed along with the case; and a case that houses the fixed piece, the movable piece, and the thermal response element The movable piece includes a terminal projecting to the outside of the case, a first elastic portion that generates an elastic force for pressing the movable contact against the fixed contact, and the first elastic portion and the terminal. A second elastic part having a lower elastic coefficient than the first elastic part, and being fixed by the case between the first elastic part and the second elastic part. Features.

In this breaker, it is preferable that the second elastic portion has a smaller cross-sectional area perpendicular to the extending direction of the movable piece from the second elastic portion to the movable contact than the first elastic portion.

In this breaker, it is preferable that a through hole is formed in the second elastic portion.

In this breaker, it is preferable that the second elastic portion is formed symmetrically with respect to the extending direction of the movable piece.

In this breaker, the case includes a case main body having an opening for accommodating the fixed piece, the movable piece, and the thermally responsive element, and a lid member that is mounted by closing the opening of the case main body. The piece is sandwiched and fixed by the case main body and the lid member, and the case main body preferably has an inclined convex portion for abutting the edge of the movable piece and positioning the movable piece. .

In this breaker, the through hole is preferably circular.

In this breaker, the case includes a case main body having an opening for accommodating the fixed piece, the movable piece, and the thermally responsive element, and a lid member that is mounted by closing the opening of the case main body. The piece is sandwiched and fixed by the case main body and the lid member, and the case main body has a cylindrical protrusion that is engaged with the through hole of the movable piece, and an inclined surface is formed on the upper portion of the protrusion. It is preferable that a tapered portion is formed.

In this breaker, it is preferable that the convex portion is formed so as to project in a semicircular shape in plan view from the end surface of the case body formed on the outer periphery of the opening.

In this breaker, it is preferable that the convex portion has a slope on the opening side.

In this breaker, it is preferable that the convex portion is formed in the vicinity of the second elastic portion of the movable piece, and the movable piece has a notch corresponding to the slope of the convex portion in the second elastic portion. .

In this breaker, if the width dimension of the through hole is X and the width dimension of the second elastic portion is Y in the width direction of the movable piece perpendicular to the extending direction of the movable piece, X: Y -X is preferably from 1.5: 1 to 1: 1.5.

According to the present invention, since the second elastic portion having a lower elastic coefficient than the first elastic portion is formed on the terminal side outside the portion where the movable piece is fixed by the case, the breaker can be manufactured, transported, or secondary Even if an external force or an impact is applied to the terminal of the movable piece in the step of incorporating into the battery, it is absorbed by the second elastic portion, and the position of the movable contact is properly maintained. As a result, the contact position between the fixed contact and the movable contact is properly maintained, the contact resistance can be stably suppressed, and the breaker can be further reduced in size.

In addition, since the cross-sectional area perpendicular to the extending direction of the movable piece is configured so that the second elastic portion is smaller than the first elastic portion, the movable piece can be easily formed by pressing or the like. It becomes possible to form the 2nd elastic part whose elastic modulus is lower than the 1st elastic part.

Further, the second elastic part having a lower elastic modulus than that of the first elastic part can be formed more easily by the through hole. Moreover, the design freedom of the elastic coefficient of the second elastic part can be increased.

In addition, since the second elastic portion is formed symmetrically with respect to the extending direction of the movable piece, the second elastic portion can be applied regardless of the rotational direction in which any external force or impact that twists the terminal of the movable piece is applied. It can be similarly absorbed by the part. Thereby, the position of the movable contact can be more appropriately maintained.

Further, since the through hole is formed in a circular shape, the concentration of stress generated in the second elastic portion can be relaxed, and the breakage of the movable piece in the second elastic portion can be suppressed.

Further, since the width dimension of the through hole and the width dimension of the second elastic portion are appropriate, the absorption effect such as impact by the second elastic portion can be further enhanced.

Also, the movable piece can be fixed with a simple configuration. Further, when the movable piece is incorporated into the case body, the movable piece can be easily and accurately positioned by the slope-shaped convex portion. As a result, the position of the movable contact can be more appropriately maintained while improving the production efficiency.

Further, since the convex portion is formed so as to project from the end surface of the case body in a semicircular shape in plan view, it is possible to suppress a reduction in the contact area between the end surface of the case main body and the lid member due to the provision of the convex portion. As a result, it is possible to firmly weld the case body and the lid member, etc., and the robustness and sealing performance of the case are enhanced, and the movable piece is firmly fixed between the first elastic portion and the second elastic portion. Can be.

Also, since the convex portion has a slope on the opening side, that is, the movable contact side, the movable contact can be positioned more accurately. In addition, since the area of the end surface of the case main body can be increased outside the convex portion, the sealing performance of the case can be improved, and the possibility that intruders undesirable for moisture, electrolytic solution, and other breakers can enter the case can be reduced.

In addition, by forming a cutout portion corresponding to the convex portion in the second elastic portion of the movable piece, the elastic coefficient of the second elastic portion can be easily reduced, and the breaker can be easily downsized. It becomes possible.

The assembly perspective view which shows the structure of the breaker by one Embodiment of this invention. The perspective view which shows the state which incorporates a cover member in a breaker main body. Sectional drawing which shows operation | movement of the breaker in a normal charge or discharge state. Sectional drawing which shows operation | movement of a breaker in the time of an overcharge state or abnormality. The perspective view which expands and shows the structure of a movable piece and a case main body. The perspective view which expands and shows the structure of the modification of a movable piece and a case main body. Sectional drawing which shows the shape of protrusion of a case main body before an assembly. Sectional drawing which shows the modification of the protrusion and convex part of a case main body before an assembly.

A breaker according to an embodiment of the present invention will be described with reference to the drawings. 1 and 2 show the configuration of the breaker. The breaker 1 includes a fixed piece 2 having a fixed contact 21, a movable piece 3 having a movable contact 31 at the tip, a thermally responsive element 4 that deforms with a change in temperature, a PTC (Positive Temperature Coefficient) thermistor 5, , A fixed piece 2, a movable piece 3, a thermally responsive element 4 and a case 6 for housing a PTC thermistor 5. The case 6 includes a case main body 61 and a lid member 62 attached to the upper surface of the case main body 61.

The fixed piece 2 is formed by pressing a metal plate mainly composed of phosphor bronze (in addition, a metal plate such as copper-titanium alloy, white or brass), and insert molding or caulking on the case body 61. It is incorporated by. A terminal 22 is formed at one end of the fixed piece 2, and a PTC thermistor 5 is placed at the center. The fixed contact 21 is formed by clad, plated or coated with a conductive material such as silver, nickel, nickel-silver alloy, copper-silver alloy, gold-silver alloy and the like, and is formed above the case body 61. It is exposed from a part of the opening 63 formed. The terminal 22 protrudes outward from one end of the case body 61.

The movable piece 3 is formed by pressing a metal plate equivalent to the fixed piece 2. A terminal 32 is formed at one end of the movable piece 3 and protrudes outward from the case body 61, and a movable contact 31 is formed at the other end. The movable contact 31 is formed at the tip of the movable piece 3 by the same material and method as the fixed contact 21. The movable piece 3 includes a fixed portion 33, a first elastic portion 34, and a second elastic portion 35 between the movable contact 31 and the terminal 32. The movable piece 3 is fixed by being sandwiched between the case main body 61 and the lid member 62 in the fixed portion 33, and the first elastic portion 34 is elastically deformed, so that the movable contact 31 formed at the tip thereof is pressed against the fixed contact 21. Thus, the fixed piece 2 and the movable piece 3 can be energized. The second elastic part 35 is formed between the fixed part 33 and the terminal 32. By providing the circular through hole 36 and the notch 37 between the fixed portion 33 and the terminal 32, the elastic coefficient of the second elastic portion 35 is set lower than that of the first elastic portion 34. Here, the elastic modulus means a rate of change of strain corresponding to the stress, and the direction of the stress is not particularly limited. The fact that the elastic coefficient of the second elastic portion 35 is lower than that of the first elastic portion 34 means that when an external force is applied to the terminal 32 to such an extent that the movable piece 3 is not destroyed, the second elastic portion 35 is more elastic than the deformation in the first elastic portion 34. The deformation in the portion 35 is large. Furthermore, in this embodiment, since the movable piece 3 is firmly fixed in the fixing portion 33 between the second elastic portion 35 and the first elastic portion 34, the stress generated in the second elastic portion 35 is the first. Almost no transmission is made to the elastic portion 34, and no deformation occurs from the first elastic portion 34 to the movable contact 31.

The width dimension of the fixed part 33 (dimension in the direction perpendicular to the extending direction of the movable piece 3) is set larger than that of the first elastic part 34 and the second elastic part 35. In addition, a small protrusion 38 is formed on the lower surface of the first elastic portion 34 so as to face the thermally responsive element 4. The small protrusion 38 and the thermally responsive element 4 are always in contact with each other, and the deformation of the thermally responsive element 4 is transmitted to the first elastic portion 34 (see FIGS. 3 and 4). The material of the movable piece 3 is preferably a material mainly composed of phosphor bronze. In addition, a conductive elastic material such as copper-titanium alloy, white or brass is also used. In addition, the movable piece 3 is curved or bent by press working in the first elastic portion 34. The degree of bending or bending is not particularly limited as long as the thermally responsive element 4 can be accommodated, and may be appropriately set in consideration of the elastic force at the operating temperature and the return temperature, the pressing force of the contact, and the like.

The thermoresponsive element 4 has a shape curved in an arc shape and is made of a composite material such as bimetal or trimetal. When the operating temperature is reached due to overheating, the curved shape is reversed, and when it falls below the return temperature due to cooling, it is restored. Since the thermoresponsive element 4 is usually a bimetal, it is hereinafter referred to as a bimetal 4 unless otherwise specified. The shape of the bimetal 4 can be formed by press working. The material and shape of the bimetal 4 are particularly limited as long as the first elastic part 34 of the movable piece 3 is pushed up by the reversing operation of the bimetal 4 at a predetermined temperature and returns to the original state by the elastic force of the first elastic part 34. However, the rectangular shape is desirable from the viewpoint of productivity and the efficiency of the reversal operation, and it is desirable that the rectangular shape is close to a square in order to efficiently push up the first elastic portion 34 while being small. The bimetal 4 may be made of various materials such as copper, nickel-manganese alloy or nickel-chromium-iron alloy on the high expansion side, iron-nickel alloy on the low expansion side, white, brass, stainless steel, etc. A material obtained by laminating two types of materials having different thermal expansion coefficients made of the above alloys is used in combination according to the required conditions.

When the energization of the fixed piece 2 and the movable piece 3 is interrupted by the reversing operation of the bimetal 4, the current flowing through the PTC thermistor 5 increases. If the PTC thermistor 5 is a positive temperature coefficient thermistor that limits the current by increasing the resistance value as the temperature rises, the type of operating current, operating voltage, operating temperature, return temperature, etc. can be selected as required. The shape is not particularly limited as long as these properties are not impaired.

The case body 61 and the lid member 62 constituting the case 6 are formed of a resin such as flame retardant polyamide, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), or polybutylene terephthalate (PBT) having excellent heat resistance. Yes. The case body 61 has an opening 63 for accommodating the fixed piece 2, the movable piece 3, the bimetal 4, the PTC thermistor 5, etc., a cylindrical protrusion 64 and a sloped convex portion that are engaged with the movable piece 3. 65 etc. are formed. The cylindrical protrusion 64 is engaged with the circular through hole 36, and the sloped convex portion 65 is engaged with the notch 37. The movable piece 3, the bimetal 4 and the PTC thermistor 5 incorporated in the case body 61 are brought into contact with each other by frames 67, 68 and 69 formed inside the opening 63, respectively, and are guided when the bimetal 4 is reversed. The

As shown in FIG. 2, a lid member 62 is mounted on the upper surface of the case body 61 so as to close the opening 63 of the case body 61 that houses the fixed piece 2, the movable piece 3, the bimetal 4, the PTC thermistor 5, and the like. The The case main body 61 and the lid member 62 are joined by ultrasonic welding. At this time, the tops of the cylindrical protrusions 64 and the sloped convex portions 65 are joined to the lid member 62. The lid member 62 may have a metal part. Having a metal part is advantageous for miniaturization from the viewpoint of mechanical strength. Further, by providing a cover terminal on the metal part, it is possible to supply a spare power source to other parts of the safety device.

FIG. 3 shows the operation of the breaker 1 in a normal charging or discharging state. In a normal charge or discharge state, the bimetal 4 is rotating forward (before inversion), the fixed contact 21 and the movable contact 31 are in contact, and both ends of the breaker 1 are passed through the first elastic portion 34 of the movable piece 3 and the like. The

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22 and 32 are electrically connected. The first elastic part 34 of the movable piece 3 and the bimetal 4 are in contact with each other, and the movable piece 3, the bimetal 4, the PTC thermistor 5 and the fixed piece 2 are electrically connected as a circuit. However, since the resistance of the PTC thermistor 5 is overwhelmingly larger than the resistance of the movable piece 3, the current flowing through the PTC thermistor 5 is completely ignored compared to the amount flowing through the fixed contact 21 and the movable contact 31. It is possible.

FIG. 4 shows the operation of the breaker 1 in an overcharged state or an abnormality. When the PTC thermistor 5 is overheated due to overcharge or abnormal condition, the bimetal 4 that has reached the operating temperature is reversed, and the first elastic portion 34 of the movable piece 3 is pushed up, and the fixed contact 21 and the movable contact 31 Are separated. At this time, the current flowing between the fixed contact 21 and the movable contact 31 is interrupted, and a slight leakage current flows through the bimetal 4 and the PTC thermistor 5. Since the PTC thermistor 5 continues to generate heat as long as such a leakage current flows, and the resistance value is drastically increased while maintaining the bimetal 4 in the inverted state, the current does not flow through the path between the fixed contact 21 and the movable contact 31. There is only a small leakage current as described above. This leakage current can be used for other functions of the safety device.

When the overcharge state is canceled or the abnormal state is resolved, the PTC thermistor 5 is no longer heated, and the bimetal 4 returns to the return temperature and is restored to the normal rotation shape. Then, the movable contact 31 and the fixed contact 21 come into contact again by the elastic force of the first elastic portion 34 of the movable piece 3, the circuit is released from the interruption state, and returns to the conduction state shown in FIG.

FIG. 5 shows the configuration of the movable piece 3 and the case body 61 in an enlarged manner. In the movable piece 3 of the present invention, the first elastic portion 34 is formed on the movable contact 31 side and the second elastic portion 35 is formed on the terminal 32 side with the fixed portion 33 interposed therebetween. And the fixing | fixed part 33 shown by hatching in the figure is pinched | interposed from the upper and lower sides by the case main body 61 and the cover member 62, and is firmly fixed, and the elastic coefficient is lower than the 1st elastic part 34 at the side of the terminal 32 of the outer side. Since the second elastic portion 35 is formed, even if an external force or an impact is applied to the terminal 32 of the movable piece 3 in the process of manufacturing, transporting, or incorporating the breaker 1 into the secondary battery, the second elastic portion 35 absorbs it. As a result, the position of the movable contact 31 is properly maintained. As a result, the contact position between the fixed contact 21 and the movable contact 31 is properly maintained, the contact resistance can be stably suppressed, and the breaker 1 can be further reduced in size.

In the present embodiment, when the movable piece 3 is formed by pressing a metal plate, the through hole 36 and the notch 37 are formed in the second elastic portion 35 by punching at the same time. Thereby, the cross-sectional area of the second elastic portion 35 cut by a plane (ZX plane in the drawing) perpendicular to the extending direction of the movable piece 3 extending from the second elastic portion 35 to the movable contact 31 is the same as that of the first elastic portion 34. It becomes smaller than a cross-sectional area, and it becomes possible to form the 2nd elastic part 35 whose elastic modulus is lower than the 1st elastic part 34 easily. In particular, in the width direction of the movable piece 3 (X direction in the figure), assuming that the width dimension (diameter) of the through hole 36 is W1 and the width dimension of the second elastic portion 35 is W2, W1: W2-W1 is 1.5. The diameter of the through hole 36 is set so as to be 1 to 1: 1.5. By setting the diameter of the through hole 36 in this manner, the absorption effect such as impact by the second elastic portion 35 can be further enhanced. Further, since the through hole 36 is formed in a circular shape, the concentration of stress generated in the second elastic portion 35 can be relaxed, and damage to the movable piece 3 in the second elastic portion 35 can be suppressed.

Further, the second elastic portion 35, the through hole 36, and the notch 37 are formed symmetrically with respect to the extending direction (Y direction in the drawing) of the movable piece. Thereby, even if an external force or impact that twists the terminal 32 of the movable piece 3 is applied in any rotation direction, it can be similarly absorbed by the second elastic portion 34, and the position of the movable contact 31 is further increased. It can be maintained properly. Note that the fixed portion 33 extends in a wing shape in the width direction of the movable piece 3, whereby the elastic coefficient of the fixed portion 33 is higher than that of the first elastic portion 34.

Further, the case body 61 is formed with a sloped convex portion 65 for contacting the edge of the notch 37 of the movable piece 3 and positioning the movable piece 3. The movable piece 3 can be easily attached to the case body 61 by engaging the through-hole 36 with the projection 64 while dropping the edge of the notch 37 of the movable piece 3 along the slope of the convex portion 65 when assembled into the case 65. It can be accurately guided and incorporated. In particular, in the present embodiment, since the pair of convex portions 65 are formed with the cylindrical projection 64 inserted and engaged in the through hole 36, the movable piece 3 is rotated about the projection 64 as an axis. Since it can prevent, the position of the movable contact 31 with respect to the fixed contact 21 in planar view can be made accurate. Thereby, the position of the movable contact 31 can be maintained more appropriately while improving the production efficiency.

In addition, since the sloped convex portion 65 is formed so as to protrude from the case main body end surface 66 in a semicircular shape in plan view, the case in which the convex portion 65 is provided while enjoying the above-described effects of the convex portion 65. A decrease in the contact area between the main body end surface 66 and the lid member 62 can be suppressed. As a result, the case main body 61 and the lid member 62 can be firmly welded and the like, and the robustness and sealing performance of the case 6 can be enhanced, and the fixing portion between the first elastic portion 34 and the second elastic portion 35 can be obtained. In 33, the movable piece 3 can be fixed firmly. In addition, the convex part 65 protruding in a semicircular shape in a plan view has good flow of the resin when the case body 61 is molded with the resin, and the productivity of the breaker 1 is not hindered. Moreover, since the convex part 65 has a slope on the opening 63 side, that is, on the movable contact 31 side, the movable contact 31 can be positioned more accurately. Further, since the area of the case main body end surface 66 can be increased outside the convex portion 65 (on the terminal 32 side), the sealing performance of the case 6 is improved, and intruders that are undesirable for moisture, electrolyte, and other breakers are present in the case 6. It is possible to reduce the possibility of intruding into the interior. In addition, since the fixed portion 33 having a larger elastic coefficient than the first elastic portion 34 is engaged with the convex portion 65, the fixed portion 33 can be fixed more accurately and firmly, and the posture of the movable piece 3 can be improved. Stabilize.

Further, since the second elastic portion 35 is disposed so as to be housed inside the case 6 when the lid member 62 is attached to the case main body 61, the movable piece 3 in the second elastic portion 35 is prevented from being damaged. Can be suppressed. Further, since the second elastic portion 35 is formed on the terminal 32 side outside the fixing portion 33 sandwiched and fixed by the case body 61 and the lid member 62, the impact applied to the terminal 32 is the second. The possibility that the case 6 is damaged by being absorbed by the elastic portion 35 can be reduced.

The present invention is not limited to the configuration of the above embodiment, and in the breaker including at least the fixed piece 2, the movable piece 3, the bimetal 4, and the case 6, the movable piece 3 includes the first elastic portion 34. The second elastic portion 35 having a lower elastic modulus than the first elastic portion 34 and the fixing portion 33 between the first elastic portion 34 and the second elastic portion 35 may be fixed by the case 6. The present invention can be modified in various ways. For example, FIG. 6 shows another form of the movable piece 3. In the movable piece 30, the through hole 36 is eliminated from the second elastic portion 35, and the dimension of the notch 37 in the Y direction is set large. Also in this embodiment, the cross-sectional area of the second elastic portion 35 cut along the ZX plane is reduced, and the elastic coefficient of the second elastic portion 35 can be made lower than that of the first elastic portion 34. Further, in the press working, by reducing the thickness dimension of the second elastic portion 35, the cross-sectional area of the second elastic portion 35 cut along the ZX plane is reduced, and the elastic coefficient of the second elastic portion 35 is changed to the first elastic coefficient. You may make it lower than the 1 elastic part 34. FIG. Alternatively, the movable piece 3 and the thermally responsive element 4 may be integrally formed by forming the movable piece 3 of bimetal or trimetal. In this case, the breaker can be made simpler and further downsized. In addition, it is most desirable that the convex portion 65 has a semicircular shape in a plan view and a slope is formed on the side of the opening 63, but may be a full moon shape or a quadrant fan shape in a plan view. In the case of a quadrant fan shape, it is possible to increase the contact area between the lid member 62 and the case body end surface 66 while maintaining the guiding function of the movable piece 3 by the convex portion 65, and thus the robustness and sealing of the case Can increase the sex.

FIG. 7 shows a cross section of the case body 61 before assembly shown in FIG. 1 cut along the ZX plane including the protrusion 64. The protrusion 64 includes a top portion 64a joined to the back surface of the lid member 62, a side surface 64b engaged with the through-hole 36 of the movable piece 3, and a sloped tapered portion formed between the top portion 64a and the side surface 64b. 64c. The tapered portion 64 c has a function of positioning the movable piece 3 together with the sloped convex portion 65 when the movable piece 3 is incorporated into the case body 61. That is, by dropping the end edge of the through hole 36 of the movable piece 3 while sliding along the inclined surface of the tapered portion 64c, the movable piece 3 can be easily and easily attached to the case body 61 in combination with the positioning effect of the inclined convex portion 65. It can be guided and placed accurately. This makes it possible to prevent a temporary stop of the breaker assembly line and improve production efficiency. Moreover, since the top part 64a of the protrusion 64 is joined to the back surface of the lid member 62, when the case main body 61 and the lid member 62 are ultrasonically welded, the joint area between the two increases, and the strength of the case 6 is further increased. Can be.

Note that the slopes of the inclined surfaces of the tapered portion 64c and the convex portion 65 are not limited to being constant, and may be configured to change according to the height. For example, as shown in FIG. 8, the inclined surfaces of the tapered portion 64c and the convex portion 65 may be formed in a convex curved surface shape. Further, the inclined surfaces of the tapered portion 64c and the convex portion 65 may be formed in a concave curved surface shape. Thus, the inclined tapered portion 64c and the convex portion 65 are not limited to those having a constant inclination.

DESCRIPTION OF SYMBOLS 1 Breaker 2 Fixed piece 3 Movable piece 4 Thermally responsive element (bimetal)
6 Case 21 Fixed contact 22 Terminal 31 Movable contact 32 Terminal 33 Fixed part 34 First elastic part 35 Second elastic part 36 Through hole 37 Notch
61 Case body 62 Lid member 63 Opening 64 Projection 64c Taper part 65 Projection part

Claims

A fixed piece having a fixed contact; a movable piece having a movable contact at a distal end; and the movable contact is pressed against and in contact with the fixed contact; In a breaker comprising a thermally responsive element that operates the movable piece so as to separate from the case, and a case that houses the fixed piece, the movable piece, and the thermally responsive element,
The movable piece is
A terminal projecting to the outside of the case; a first elastic part for generating an elastic force for pressing the movable contact against the fixed contact; and formed between the first elastic part and the terminal, A second elastic part having a lower elastic modulus than the first elastic part,
A breaker fixed between the first elastic portion and the second elastic portion by the case.
2. The second elastic portion according to claim 1, wherein a cross-sectional area perpendicular to an extending direction of the movable piece from the second elastic portion to the movable contact is smaller than that of the first elastic portion. Breaker.
The breaker according to claim 1 or 2, wherein the second elastic portion is formed with a through hole.
The breaker according to any one of claims 1 to 3, wherein the second elastic portion is formed symmetrically with respect to the extending direction of the movable piece.
The case includes a case main body having an opening for accommodating the fixed piece, the movable piece, and the thermally responsive element, and a lid member that is mounted to close the opening of the case main body, and the movable piece includes the case Sandwiched and fixed between the main body and the lid member,
The said case main body contact | abuts the edge of the said movable piece, and has a slope-shaped convex part for positioning this movable piece, The Claim 1 thru | or 4 characterized by the above-mentioned. breaker.
The breaker according to any one of claims 3 to 5, wherein the through hole is circular.
The case includes a case main body having an opening for accommodating the fixed piece, the movable piece, and the thermally responsive element, and a lid member that is mounted to close the opening of the case main body, and the movable piece includes the case Sandwiched between the body and the lid member and fixed,
The case body has a cylindrical protrusion that is engaged with the through hole of the movable piece,
The breaker according to claim 6, wherein a sloped tapered portion is formed on an upper portion of the protrusion.
The said convex part is formed so that it may protrude in a semicircle shape in planar view from the case main body end surface formed in the outer periphery of the said opening, The Claim 5 thru | or 7 characterized by the above-mentioned. breaker.
The breaker according to claim 8, wherein the convex portion has a slope on the opening side.
The convex portion is formed in the vicinity of the second elastic portion of the movable piece,
10. The breaker according to claim 7, wherein the movable piece has a notch corresponding to the slope of the convex portion in the second elastic portion.
In the width direction of the movable piece perpendicular to the extending direction of the movable piece, assuming that the width dimension of the through hole is X and the width dimension of the second elastic portion is Y, X: Y−X is 1. The breaker according to any one of claims 3 to 10, wherein the breaker is 5: 1 to 1: 1.5.