WO2012169442A1

WO2012169442A1 - Breaker, safety circuit including same, and secondary battery pack

Info

Publication number: WO2012169442A1
Application number: PCT/JP2012/064270
Authority: WO
Inventors: 北川俊也
Original assignee: 株式会社小松ライト製作所
Priority date: 2011-06-08
Filing date: 2012-06-01
Publication date: 2012-12-13
Also published as: JPWO2012169442A1; JP5452771B2

Abstract

A breaker (1) includes: a fixed piece (2) that has a fixed contact (21); a movable piece (4) that has a movable contact (3), and presses the movable contact (3) against the fixed contact (21) to bring the movable contact (3) into contact with the fixed contact (21); a thermally-actuated element (5) that actuates the movable piece (4) so as to separate the movable contact (3) from the fixed contact (21) by deformation with changes in temperature; and a resin case (7) that houses the fixed piece (2), the movable piece (4), and the thermally-actuated element (5). A lid member (72) of the resin case (7) is molded integrally with a plate-like cover piece (8) having bead portions (81). The bead portions (81) reinforce the lid member (72), and the breaker (1) can be further reduced in size and thickness while maintaining a stable contact/non-contact state between the fixed contact (21) and the movable contact (3).

Description

Breaker, safety circuit including the same, and secondary battery pack

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

In the case of breakers using bimetal, abnormalities such as when an overcurrent flows through a motor or the like installed in a device such as an automobile or home appliance, or when the temperature of the secondary battery during charging or discharging rises excessively occur. At the same time, it is used as a protection device that cuts off the current flowing in the motor, the secondary battery and the like. Such breakers, when used in DC circuits for motors and chargers for automobiles, AC circuits for fan motors and washing machines for air conditioners, etc., can operate accurately to ensure the safety of equipment. Desired. Further, when used in a secondary battery or the like equipped in a mobile phone, a notebook computer, etc., in addition to ensuring the above-described safety, further downsizing has been demanded with recent downsizing of devices.

Patent Document 1 discloses a breaker using such a bimetal. The breaker shown in the same document is a fixed piece (base terminal), movable piece (movable arm), bimetal, PTC (Positive s Temperature Coefficient) thermistor, etc. housed in a resin case. One terminal is used by being connected to an electric circuit of an electric device.

In FIG. 3 and the like of the same document, an embodiment in which a cover piece (cover terminal) is insert-molded on the lid member of the resin case is disclosed. The cover piece has an intermediate retainer and a stopper, and even if the movable piece is pushed up by a small width, the movable piece will come into contact with the intermediate restraint and the stopper to increase the width of the movable contact's movable contact. Separate the contact of the movable piece and the contact of the fixed piece.

Japanese Patent No. 4170232

However, a structure that accommodates all the above-described components in a resin case and maintains a stable contact / non-contact state between the fixed contact provided on the fixed piece and the movable contact provided on the movable piece; In order to achieve this, it is necessary to provide the resin case as a housing with appropriate rigidity and strength. The rigidity and strength of the resin case can be improved by increasing the thickness of the case body of the resin case, the thickness of the lid member, and the thickness of the cover piece. It became a factor that hindered downsizing and thinning (low profile).

The present invention has been made to solve the above-described problem, and provides a breaker capable of realizing further downsizing and thinning while maintaining a stable contact / non-contact state between a fixed contact and a movable contact. The purpose is to provide.

In order to achieve the above object, the present invention has a fixed piece having a fixed contact, a movable contact, a movable piece that presses and contacts the movable contact with the fixed contact, and is deformed as the temperature changes. A breaker comprising: a thermal response element that operates the movable piece so that the movable contact is separated from the fixed contact; and a resin case that houses the fixed piece, the movable piece, and the thermal response element. Is characterized in that a plate-like cover piece having a bead portion is integrally formed.

According to the breaker of the present invention, the resin case is integrally formed with a plate-like cover piece having a bead, so that the rigidity and strength of the resin case can be drastically increased without increasing the thickness of the breaker. Can be increased. In addition, if the rigidity and strength are the same as those of the prior art, the thickness of the resin case and the cover piece can be reduced, and the thickness of the breaker can be reduced to achieve downsizing and thinning.

The assembly perspective view which shows the structure of the breaker by 1st Embodiment of this invention. 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 top view which shows the structure of the cover member of the breaker. (A) is the sectional view on the AA line in FIG. 4, (b) is the sectional view on the BB line in FIG. The top view which shows the structure of the cover piece of the breaker. The perspective view which shows the structure of the cover piece. (A) is a bending stress applied to a breaker, (b) is a bending stress applied to a breaker, (c) is a figure which shows the pressing stress applied to a breaker. The top view which shows the structure of the modification of the bead part formed in a cover piece. The top view which shows the structure of another modification of the bead part formed in a cover piece. Sectional drawing which shows the structure of the breaker by 2nd Embodiment of this invention. Sectional drawing which shows the operation | movement of the breaker in the overcharge state or the time of abnormality. Sectional drawing which shows the structure of the cover member applied to the breaker. Sectional drawing which shows the structure of the metal mold | die which embeds a cover piece and shape | molds a cover member in the breaker. Sectional drawing which shows the structure of the modification of the breaker. The top view which shows the structure of the secondary battery pack provided with the breaker of this invention. The circuit diagram of the safety circuit for electric equipment provided with the breaker of this invention.

(First embodiment)
A breaker according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of a breaker according to the first embodiment. The breaker 1 includes a fixed piece 2 having a fixed contact 21, a movable piece 4 having a movable contact 3 at the tip, a thermally responsive element 5 that deforms with a change in temperature, and a PTC (Positive Temperature Coefficient) thermistor 6. , A fixed piece 2, a movable piece 4, a thermally responsive element 5, and a resin case 7 that accommodates a PTC thermistor 6. The resin case 7 includes a case body 71 and a lid member 72 attached to the upper surface of the case body 71.

The fixed piece 2 is formed by pressing a conductive metal plate such as phosphor bronze (in addition, a metal plate such as copper-titanium alloy, white or brass), and is incorporated into the case body 71 by insert molding. It is. A terminal 22 is formed at one end of the fixed piece 2, and a PTC thermistor 6 is placed at the center. The fixed contact 21 is formed by clad, plating, coating, or the like of a conductive material such as silver, silver-nickel alloy, copper-silver alloy, gold-silver alloy, and the like, and is formed above the case body 71. A part of the opening 73 is exposed. The terminal 22 protrudes outward from one end of the case body 71.

The movable piece 4 is formed in an arm shape by pressing a metal plate equivalent to the fixed piece 2. A terminal 41 is formed at one end in the longitudinal direction of the movable piece 4 and protrudes outward from the case body 71, and a movable contact 3 is formed at the other end (corresponding to the tip of the arm-shaped movable piece 4). The movable contact 3 is formed of the same material as that of the fixed contact 21 and is joined to the tip of the movable piece 4 by a technique such as welding. The movable piece 4 has a fixed portion 42 (corresponding to the base end of the arm-shaped movable piece 4) and an elastic portion 43 between the movable contact 3 and the terminal 41. The movable piece 4 is fixed by being sandwiched between the case main body 71 and the lid member 72 in the fixed portion 42, and the elastic portion 43 is elastically deformed, whereby the movable contact 3 formed at the tip thereof is pressed against the fixed contact 21 side. Thus, the fixed piece 2 and the movable piece 4 can be energized.

Further, a protrusion 44 is formed on the lower surface of the elastic portion 43 so as to face the thermal response element 5. The protrusions 44 are in contact with the thermally responsive element 5 and efficiently transmit the deformation of the thermally responsive element 5 to the elastic portion 43 (see FIGS. 2 and 3). As the material of the movable piece 4, a material having good conductivity such as phosphor bronze is preferable. In addition, a conductive elastic material such as copper-titanium alloy, white or brass is also used. Note that the movable piece 4 is curved or bent at the elastic portion 43 by press working. The degree of bending or bending is not particularly limited as long as the thermally responsive element 5 can be accommodated, and may be set as appropriate in consideration of the elastic force at the operating temperature and the return temperature, the pressing force of the contacts, and the like.

The thermoresponsive element 5 has a curved shape 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 5 is usually a bimetal, it is hereinafter referred to as a bimetal 5 unless otherwise specified. The shape of the bimetal 5 can be formed by pressing. The material and shape of the bimetal 5 are not particularly limited as long as the elastic part 43 of the movable piece 4 is pushed up by the reversing operation of the bimetal 5 at a predetermined temperature and returns to the original state by the elastic force of the elastic part 43. From the viewpoint of productivity and efficiency of the reversal operation, a rectangle is desirable, and a rectangle close to a square is desirable in order to efficiently push up the elastic portion 43 while being small. The bimetal 5 is made of, for example, 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. What laminated | stacked two types of materials which differ in the thermal expansion coefficient which consists of various alloys is used in combination according to a required condition.

When the energization of the fixed piece 2 and the movable piece 4 is interrupted by the reversing operation of the bimetal 5, the current flowing through the PTC thermistor 6 increases. As long as the PTC thermistor 6 is a positive temperature coefficient thermistor that limits the current by increasing the resistance value as the temperature rises, the type of operation current, operation voltage, operation temperature, return temperature, etc. can be selected as necessary. The shape is not particularly limited as long as these properties are not impaired.

The case main body 71 and the lid member 72 constituting the resin case 7 are formed of a resin such as flame retardant polyamide, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polybutylene terephthalate (PBT) having excellent heat resistance. ing. The case body 71 is formed with an opening 73 for accommodating the fixed piece 2, the movable piece 4, the bimetal 5, the PTC thermistor 6, and the like. The movable piece 4, the bimetal 5 and the PTC thermistor 6 incorporated in the case body 71 are brought into contact with each other by frames 74, 75 and 76 formed inside the opening 73, and are guided when the bimetal 5 is reversed. The

The cover piece 8 is embedded in the lid member 72 by insert molding. The cover piece 8 is covered with the lid member 72 over the entire upper surface. The cover piece 8 is formed by pressing a metal plate mainly composed of phosphor bronze or a metal plate such as stainless steel. As shown in FIGS. 2 and 3, the cover piece 8 is appropriately brought into contact with the upper surface of the movable piece 4 to restrict the movement of the movable piece 4, and the rigidity of the resin case 7 as a casing and the casing 7 as a case. Increase strength.

As shown in FIG. 1, a lid member 72 is mounted on the upper surface of the case body 71 so as to close the opening 73 of the case body 71 that houses the fixed piece 2, the movable piece 4, the bimetal 5, the PTC thermistor 6, and the like. The The case main body 71 and the lid member 72 are usually joined by ultrasonic welding. The lid member 72 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. 2 shows the operation of the breaker 1 in a normal charging or discharging state. In a normal charge or discharge state, the bimetal 5 is rotating forward (before reversal), the fixed contact 21 and the movable contact 3 are in contact, and both terminals 22 of the breaker 1 through the elastic portion 43 of the movable piece 4 and the like. , 41 are electrically connected. The elastic part 43 of the movable piece 4 and the bimetal 5 are in contact with each other, and the movable piece 4, the bimetal 5, the PTC thermistor 6 and the fixed piece 2 are electrically connected as a circuit. However, since the resistance of the PTC thermistor 6 is overwhelmingly larger than the resistance of the movable piece 4, the current flowing through the PTC thermistor 6 is completely ignored compared to the amount flowing through the fixed contact 21 and the movable contact 3. It is possible.

FIG. 3 shows the operation of the breaker 1 in an overcharged state or an abnormality. When the PTC thermistor 6 is overheated due to overcharging or abnormalities, the bimetal 5 that has reached the operating temperature is reversed, the elastic portion 43 of the movable piece 4 is pushed up, and the fixed contact 21 and the movable contact 3 are separated. To do. At this time, the current flowing between the fixed contact 21 and the movable contact 3 is interrupted, and a slight leakage current flows through the bimetal 5 and the PTC thermistor 6. Since the PTC thermistor 6 continues to generate heat as long as such a leakage current flows, and the resistance value is drastically increased while maintaining the bimetal 5 in the inverted state, the current does not flow through the path between the fixed contact 21 and the movable contact 3, There is only a small leakage current as described above (constituting a self-holding circuit). 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 6 is no longer heated, and the bimetal 5 returns to the return temperature and is restored to the normal rotation shape. Then, the movable contact 3 and the fixed contact 21 come into contact again by the elastic force of the elastic portion 43 of the movable piece 4, the circuit is released from the interruption state, and returns to the conduction state shown in FIG.

4 and 5 show the lid member 72 in which the cover piece 8 is embedded. A concave portion 72a is formed on the inner surface of the lid member 72 so as to be recessed upward from the edge thereof, and the cover piece 8 faces the concave portion 72a and is exposed to the inner surface side of the lid member 72 (inside the resin case 7). is doing.

6 and 7 show the cover piece 8 embedded in the lid member 72. The cover piece 8 is formed by punching a metal plate by press working. A plurality of linearly continuous bead portions 81 are formed on the cover piece 8 so as to protrude in the outer direction of the lid member 72, that is, in the direction in which the top surface 72b of the lid member 72 is formed during insert molding. In the present embodiment, a plurality of bead portions 81 are extended in parallel along the longitudinal direction of the resin case 7 on the upper surface of the cover piece 8. Thus, the shape of the bead portion 81 preferably includes a component in the longitudinal direction of the breaker 1 because an external force such as bending or bending (see FIG. 8) is easily applied to the breaker 1. By providing unevenness corresponding to the bead portion 81 in the press mold, the bead portion 81 is simultaneously formed in the step of punching the cover piece 8 from the metal plate by press working. Therefore, the productivity of the breaker 1 of the present embodiment is not different from that of the conventional breaker, and there is no possibility of increasing the cost.

FIG. 8 shows an example of stress applied to the breaker 1. That is, in FIG. 8, (a) shows a state in which bending stress is applied to the breaker 1, (b) shows a state in which bending stress is applied to the breaker 1, and (c) shows a state in which pressing stress is applied to the breaker 1. In (a), one end of the breaker 1 is held by the holding

portions

10 and 11, in (b), both end portions of the breaker 1 are placed on the holding

portions

12 and 13, and in (c), The breaker 1 is placed on a holding table 14. The breaker 1 is pressed by the pressing portion 15 in the direction of the white arrow, and stress is applied. The inventor of the present application energizes the breaker 1 of the present embodiment having the conventional breaker and the cover piece 8 formed with the bead portion 81 while applying bending stress, bending stress, or pressing stress, and the resistance value is predetermined. The contact / non-contact state between the fixed contact and the movable contact was confirmed by measuring the stress when the lower limit of the standard value was reached. As a result, it was confirmed that the breaker 1 of this embodiment has a higher stress when the resistance value reaches the lower limit of the standard value as compared with the breaker of the member and the cover piece having the same structure as the conventional one. From this, it was confirmed that the breaker 1 of this embodiment maintains a stable contact / non-contact state between the fixed contact and the movable contact even when the applied stress increases.

As described above, according to the breaker 1 of the present embodiment, since the plate-like cover piece 8 having the bead portion 81 is integrally formed on the lid member 72 of the resin case 7, the thickness of the breaker 1. Without increasing the rigidity, the rigidity and strength of the resin case 7 can be dramatically increased. In addition, if the rigidity and strength are the same as the conventional one, the thickness of the top surface 72b of the lid member 72 and the cover piece 8 can be reduced, and the thickness of the breaker 1 can be reduced to reduce the size and thickness. It becomes possible to plan.

Further, from the viewpoint of space efficiency, the cover piece 8 is preferably disposed on the inner surface of the resin case 7, and the bead portion 81 protrudes in the outer direction of the resin case 7. By forming the bead part 81 projecting outward, the projecting bead part 81 is embedded in the top surface 72b of the lid member 72 and does not project from the inner surface or the outer surface of the resin case 7. . As a result, the thickness of the breaker 1 can be further reduced, and the size and thickness can be reduced.

Further, by extending the bead portion 81 along the longitudinal direction of the resin case 7, it is possible to increase the rigidity and strength against bending, bending, etc. of the resin case 7 in particular, and even in the situation where the stress described above is applied. It is possible to maintain a stable operation while reducing the size and thickness of the breaker 1.

(Modification)
FIG. 9 shows a modification of the bead portion 81 formed on the cover piece 8. In this modification, the bead portion 81 extends along the longitudinal direction of the resin case 7 while meandering. According to this modification, in addition to the above-described bending, bending, pressing, etc., the rigidity and strength against torsion can be increased, and the breaker 1 can be reduced in size and thickness even in a situation where torsional stress is applied. It is possible to maintain the operation performed.

(Modification)
FIG. 10 shows another modification of the bead portion 81 formed on the cover piece 8. In this modification, the bead portion 81 is formed at an angle of attack of about 45 ° with respect to the longitudinal direction of the resin case 7. The angle of attack of the bead portion 81 with respect to the longitudinal direction of the resin case 7 is not limited to approximately 45 °, and can be set as appropriate according to the orientation of the breaker 1 mounted on a secondary battery or the like. In this modification, the bead portion 81 extends in a specific direction as described above, whereby the rigidity / strength in a specific direction according to the posture of the breaker 1 mounted on the secondary battery or the like. Therefore, it is possible to maintain a stable operation while reducing the size and thickness of the breaker 1. Furthermore, the specific direction mentioned here is not limited to a uniform direction, and may be a plurality of directions. In this case, the bead portions 81 may be formed so as to cross each other. In such a configuration, the rigidity and strength of the breaker 1 can be improved as a whole.

(Second Embodiment)
FIG. 11 shows a configuration of a breaker according to the second embodiment of the present invention. FIG. 12 shows the operation of the breaker in an overcharged state or when an abnormality occurs. The breaker 1 </ b> A is different from the breaker 1 in that an opening 79 is provided in the top surface 72 b of the lid member 72 and that

projections

82 a and 82 b are provided in the cover piece 8.

FIG. 13 shows the configuration of the lid member 72 in the AA line section and the BB line section equivalent to FIG. The opening 79 is formed to penetrate the top surface 72 b of the lid member 72 from the outer surface of the lid member 72. The cover piece 8 is partially exposed by the opening 79. The opening 79 is formed at a location that does not overlap with the bead portion 81 and the

protrusions

82a and 82b in plan view. For this reason, the bead part 81 and the

protrusions

82a and 82b are not exposed to the outside of the resin case 7. That is, the outer side (the upper side in FIG. 11) of the cover piece 8 where the bead portion 81 and the

protrusions

82 a and 82 b are formed is covered with the resin constituting the top surface 72 b of the lid member 72.

Since the bead portion 81 and the

protrusions

82a and 82b are formed, the surface area of the cover piece 8 is locally increased, and heat tends to be easily released at that portion. However, in the breaker 1A of the present invention, the outside of the portion of the cover piece 8 where the bead portion 81 and the

protrusions

82a and 82b are formed is covered with the resin constituting the top surface 72b of the lid member 72. Since the bead part 81 and the

protrusions

82a and 82b are not exposed to the outside of the resin case 7, it is possible to suppress an increase in heat released from the bead part 81 and the

protrusions

82a and 82b. In addition, the effect which suppresses that the heat discharge | released from this bead part 81 increases is shown in FIG. 1 thru | or FIG. 5, and the top surface 72b of the cover member 72 covers the upper surface of the cover piece 8 over the whole area. The same applies to the covered breaker 1 according to the first embodiment.

The

protrusions

82a and 82b are arranged on the line AA in FIG. 4 (that is, on the center line in the longitudinal direction of the lid member 72), and are sandwiched by a plurality of bead portions 81 in FIG. 13B. Further, as is clear from FIG. 13A, since the bead portion 81 is disposed in the vicinity of the bead portion 81 to such an extent that the reinforcement effect reaches, even if any external force is applied to the lid member 72, the protrusion Deformation of 82a and 82b and the vicinity thereof, that is, fluctuations in the position and posture of the

projections

82a and 82b are suppressed.

The

protrusions

82a and 82b formed on the cover piece 8 protrude toward the inner side of the resin case 7, that is, toward the movable piece 4. The protrusion 82 a is disposed in the vicinity of the protrusion 44 a of the

movable piece

4, and 82 b is disposed in the vicinity of the protrusion 44 b of the movable piece 4. The protrusion 44 a of the movable piece 4 is disposed in the vicinity of the fixed portion 42, and the protrusion 44 b of the movable piece 4 is disposed in the vicinity of the movable contact 3.

The protrusion 82a is always in contact with the front surface of the movable piece 4, and heat is exchanged between them. That is, as shown in FIG. 11, when the movable contact 3 and the fixed contact 21 are in contact (when the fixed piece 2 and the movable piece 4 are in a conductive state), and as shown in FIG. When 3 is separated from the fixed contact 21 (when the fixed piece 2 and the movable piece 4 are in a non-conducting state), the movable piece 4 is in contact with the cover piece 8 via the protrusion 82a. The protrusion 82b is separated from the movable piece 4 in the conductive state shown in FIG. 11, and contacts the movable piece 4 and restricts deformation of the movable piece 4 in the non-conductive state shown in FIG.

FIG. 14 shows a configuration of a mold for embedding the cover piece 8 and molding the lid member 72. The mold 100 is covered with a cover piece 8 in a cavity space 103 defined by a first mold 101 and a second mold 102 and filled with a resin material from a nozzle (not shown) and cured. The member 72 is formed. The first mold 101 molds the inner surface (back surface) of the lid member 72, and the second mold 102 molds the outer surface (front surface) of the lid member 72.

The second mold 102 is in contact with the surface of the cover piece 8 placed on the first mold 101, and a fixing portion 104 that presses and fixes the cover piece 8 against the first mold 101 is provided in the cavity space 103. Protrusively formed. When insert molding is performed, the cover piece 8 may be displaced in the mold due to the pressure of the resin material to be filled. In the present mold 100, since the cover piece 8 is sandwiched and fixed by the first mold 101 and the tip of the fixing portion 104, there is no possibility of causing a positional shift even if pressure is applied from the resin material. Thereby, the lid member 72 in which the cover piece 8 is embedded with high accuracy can be formed.

In the mold 100, insert molding is performed in a state where the tip of the fixing portion 104 is in contact with the surface of the cover piece 8. Therefore, the lid member 72 has an opening 79 penetrating the top surface 72 b. The Since the opening 79 penetrates the top surface 72 b of the lid member 72 in the thickness direction, a part of the surface of the cover piece 8 is exposed from the opening 79. In other words, by providing the lid member 72 with the opening 79 that penetrates the top surface 72b and exposes a part of the cover piece 8, the lid member 72 in which the cover piece 8 is embedded with high accuracy can be formed.

According to the breaker 1A of the present embodiment, at least the outside of the cover piece 8 where the bead portion 81 is formed is covered with the top surface 72b of the lid member 72, so that the movable contact 3 is the fixed contact 21. The member 72 can prevent the heat transmitted from the movable piece 4 to the cover piece 8 from being released to the outside of the breaker 1 </ b> A when being separated from the breaker 1 </ b> A. As already described, the surface area of the portion where the bead portion 81 is formed tends to increase locally, and the released heat tends to increase. In the breaker 1 </ b> A, the outside of the portion where the bead portion 81 is formed is covered with the lid member 72 of the resin case 7, thereby suppressing the release of heat from the bead portion 81. Thereby, the temperature fall of the bimetal 5 can be suppressed and it can prevent that the deformation | transformation state of the bimetal 5 recovers in the breaker which has a self-holding function.

Further, the cover piece 8 has a protrusion 82 a that protrudes inward of the resin case 7, and the protrusion 82 a comes into contact with the movable piece 4 to urge the elastic portion 43 of the movable piece 4 toward the fixed contact 21. . Thereby, the contact state of the movable contact 3 and the fixed contact 21 is kept good in the conductive state shown in FIG. Thereby, the contact resistance between the movable contact 3 and the fixed contact 21 during energization can be stably maintained low. Further, the cover piece 8 has a protrusion 82 b protruding toward the inner side of the resin case 7, and the protrusion 82 b comes into contact with the movable piece 4 to restrict deformation of the movable piece 4. Thereby, the front-end | tip part of the movable piece 4 is controlled by an exact position. At this time, due to the reaction, the cover piece 8 receives a reaction force from the

projections

82a and 82b, but since it is reinforced by the bead portion 81, the deformation of the cover piece 8 is suppressed, and the positions of the

projections

82a and 82b are reduced. Variation is suppressed. As a result, the movable piece 4 is regulated at a more accurate position, and excessive deformation of the movable piece 4 can be suppressed and the movable contact 3 can be put on standby at an appropriate position. In addition, the movable piece 4 is urged with an appropriate force, and the contact state between the movable contact 3 and the fixed contact 21 is kept good.

In the assembling process in which the case main body 71 and the lid member 72 are joined by ultrasonic welding or the like, the lid member 72 is subjected to an appropriate pressure in order to eliminate the gap between them and improve the sealing performance. 71 is pressed. According to the present invention, since the cover piece 8 embedded in the lid member 72 is reinforced by the bead portion 81, deformation of the cover piece 8 is suppressed even in a situation where a large pressure is applied to the lid member 72. . Accordingly, the relative positional accuracy between the assembled

projections

82a and 82b and the movable piece 4 is improved, and the movable contact 3 is kept in a proper position and the movable piece 4 is attached with an appropriate force as described above. As a result, the contact state between the movable contact 3 and the fixed contact 21 is kept good. As a result, even in a mass-produced breaker, it is possible to stabilize the resistance value when energized to a low level and obtain good temperature characteristics, that is, to accurately follow the temperature and cut off the current.

Further, since the cover piece 8 is always in contact with the movable piece 4 at the protrusion 82 a, the elastic portion 43 of the movable piece 4 can be constantly urged toward the fixed contact 21 by the protrusion 82 a of the cover piece 8. Is stable, and the contact state between the movable contact 3 and the fixed contact 21 is kept good.

Moreover, since the outer surface of the resin case 7 has the opening 79 which penetrates the resin case 7 and exposes a part of the cover piece 8, the resin case 7 and the cover piece 8 are integrally formed by insert molding or the like. At this time, the cover piece 8 can be fixed in an accurate position and posture. Thereby, the precision of the cover piece 8 with respect to the resin case 7 can be improved, the movable piece 4 is regulated at a more accurate position, and is urged with an appropriate force, so that the movable contact 3 and the fixed contact 21 are in contact with each other. Is kept even better.

(Modification)
FIG. 15 shows a configuration of a breaker 1B according to a modification of the breaker 1A. The breaker 1B is different from the breaker 1A in that

bead portions

83a and 83b are formed so as to protrude toward the inner side of the resin case 7. The recesses on the surface side of the

bead parts

83a and 83b are filled with a resin material. The bead portion 83a is always in contact with the surface of the movable piece 4 in the vicinity of the protrusion 44a, and is formed in a position and shape that urges the elastic portion 43 toward the fixed contact 21 side. The bead portion 83b is formed in a position and shape that contacts the surface of the movable piece 4 in the vicinity of the protrusion 44b when the movable contact 3 is separated from the fixed contact 21, and restricts deformation of the movable piece 4. Accordingly, the

protrusions

82a and 82b are abolished.

According to the breaker 1B, the

bead portions

83a and 83b are formed to protrude toward the inner side of the resin case 7, and the

bead portions

83a and 83b come into contact with the movable piece 4 to regulate or bias the movable piece 4. Since the

bead portions

83a and 83b have the effect of increasing the rigidity by themselves, the movable piece 4 is regulated at an accurate position and is urged by an appropriate force so that the contact state between the movable contact 3 and the fixed contact 21 is good. Kept. Moreover, even if the

projections

82a and 82b are eliminated, the same effect can be obtained. Therefore, the structure of the cover piece 8 can be simplified and the cost of the breaker 1B can be reduced.

In addition, this invention is not restricted to the structure of the said embodiment, The plate-shaped cover piece 8 which has the bead part 81 at least in the resin case 7 should just be shape | molded integrally. The shape, number, arrangement, and the like of the bead portion 81 can be appropriately determined according to the use required for the breaker. Further, instead of the bead portion 81 having a uniform thickness formed by press molding as illustrated in FIG. 5B, fins, ribs, or the like may be used as the convex reinforcing portions. The material of the cover piece 8 is not limited to a metal, and may be a material (for example, a carbon fiber composite material) having higher rigidity and strength than the resin constituting the lid member 72. In addition, the resin case 7 is not limited to the form in which the case main body 71 and the lid member 72 are joined by ultrasonic welding, but may be a form integrally formed. Further, the movable piece 4 and the thermally responsive element 5 may be integrally formed by forming the movable piece 4 from bimetal or trimetal. In this case, it is possible to further simplify the configuration of the breaker and further reduce the size and thickness. In the present embodiment, the self-holding circuit using the PTC thermistor 6 is provided. However, the present invention can be applied to a configuration in which such a configuration is omitted, and the breaker 1 can be reduced in size while suppressing conduction resistance. Can be achieved.

Further, the joining technique between the resin base 71 and the cover member 72 is not limited to ultrasonic welding, and any technique can be applied as long as both are firmly joined. For example, a liquid or gel (glue) adhesive may be applied, filled, and cured to bond them together. Further, the resin case 7 is not limited to the form constituted by the resin base 71 and the cover member 72 and the like, but may be any form as long as the movable piece 4 is sandwiched and held by two or more parts. In this case, one is the first case and the other is the second case.

Further, the present invention is applied to a form in which the fixed portion 42 or the vicinity thereof is structurally separated into the terminal 41 side and the movable contact 3 side as shown in JP-A-2005-203277. Also good.

Also, the breaker 1 of the present invention can be widely applied to secondary battery packs, safety circuits for electrical devices, and the like. FIG. 16 shows the secondary battery pack 9. The secondary battery pack 9 includes a secondary battery 91 and a breaker 1 provided in an output terminal circuit of the secondary battery 91. FIG. 17 shows a safety circuit 90 for electrical equipment. The safety circuit 90 includes the breaker 1 in series in the output circuit of the secondary battery 91.

As described above, the present invention includes at least a fixed piece having a fixed contact, a movable contact, a movable piece that presses the movable contact against the fixed contact, and is deformed in accordance with a temperature change. A breaker comprising: a thermal response element that operates the movable piece so that the movable contact is separated from the fixed contact; and a resin case that houses the fixed piece, the movable piece, and the thermal response element. The plate-shaped cover piece having the bead portion only needs to be integrally formed.

According to this breaker, the resin case is integrally formed with a plate-like cover piece having a bead, so that the rigidity and strength of the resin case can be dramatically increased without increasing the thickness of the breaker. Can do. In addition, if the rigidity and strength are the same as those of the prior art, the thickness of the resin case and the cover piece can be reduced, and the thickness of the breaker can be reduced to achieve downsizing and thinning.

In this breaker, when at least the outside of the cover piece where the bead portion is formed is covered with the resin case and at least the movable contact is separated from the fixed contact, the movable piece is It is preferable to be in contact with the cover piece.

According to the configuration in which at least the outside of the portion where the bead portion is formed is covered with the resin case, the heat transmitted from the movable piece to the cover piece when the movable contact is separated from the fixed contact. Can be prevented by the resin case from being released to the outside of the breaker. In particular, in the portion where the bead portion is formed, the surface area tends to increase locally, and the released heat tends to increase. The present invention suppresses the release of heat from the bead part by covering the outside of the part where the bead part is formed with a resin case. Thereby, the temperature fall of a thermally responsive element can be suppressed and it can prevent that the deformation | transformation state of a thermally responsive element recovers in the breaker which has a self-holding function.

In this breaker, it is preferable that the cover piece has a protrusion protruding toward the inner side of the resin case so as to be in contact with the movable piece.

According to the configuration in which the cover piece has a protrusion that protrudes toward the inside of the resin case, the protrusion comes into contact with the movable piece to restrict or bias the movable piece. At this time, due to the reaction, the cover piece receives a reaction force from the protrusion, but since it is reinforced by the bead portion, the deformation of the cover piece is suppressed and the fluctuation of the position of the protrusion is suppressed. As a result, the movable piece is regulated at an accurate position, and is urged by an appropriate force, so that the contact state between the movable contact and the fixed contact is kept good.

In this breaker, it is preferable that the bead portion is formed so as to protrude inward of the resin case so that a part of the bead portion can come into contact with the movable piece.

According to the configuration in which the bead portion is formed so as to protrude toward the inner side of the resin case, the movable piece can be regulated or urged by bringing the bead portion into contact with the movable piece. At this time, since the bead portion itself has an effect of increasing the rigidity, the movable piece is regulated at an accurate position and is urged by an appropriate force to maintain a good contact state between the movable contact point and the fixed contact point. It is.

In this breaker, it is preferable that the cover piece is always in contact with the movable piece at least at one place.

According to the configuration in which the cover piece is always in contact with the movable piece at least at one place, the movable piece can be constantly urged by the cover piece, so that the posture of the movable piece is stabilized.

In this breaker, it is preferable that the outer surface of the resin case has an opening that penetrates the resin case and exposes a part of the cover piece.

According to the configuration in which the outer surface of the resin case has an opening that penetrates the resin case and exposes a part of the cover piece, when the resin case and the cover piece are integrally formed by insert molding or the like, the cover piece is It can be fixed in an accurate position and posture. As a result, the accuracy of the cover piece with respect to the resin case can be improved, the movable piece is regulated at a more accurate position, and the contact state between the movable contact point and the fixed contact point is further improved by being biased with an appropriate force. To be kept.

In this breaker, it is preferable that the cover piece is disposed on the inner surface of the resin case and protrudes outward.

The cover piece is disposed on the inner surface of the resin case, and the bead portion is formed so as to protrude outward, so that the protruded bead portion is embedded in the resin case. Or it does not protrude from the outer surface. As a result, the thickness of the breaker can be further reduced, and the size and thickness can be reduced.

In this breaker, it is preferable that the bead portion extends along the longitudinal direction of the resin case.

By extending the bead portion along the longitudinal direction of the resin case, it is possible to increase the rigidity and strength against bending, bending, pressing, etc. of the resin case in particular. It is possible to maintain stable operation while reducing the size and thickness.

In this breaker, it is preferable that the bead portion extends along a specific direction.

By extending the bead part along a specific direction, the rigidity and strength in a specific direction can be increased according to the orientation of the breaker mounted on the secondary battery, etc. It is possible to maintain a stable operation while achieving shape.

Further, the safety circuit for an electric device according to the present invention is characterized by including the breaker.

Further, the secondary battery pack of the present invention is characterized by including the breaker.

Further, according to the safety circuit or the secondary battery pack provided with the breaker of the present invention, it becomes possible to easily manufacture the safety circuit or the secondary battery pack that is downsized.

1, 1A, 1B Breaker 2 Fixed piece 3 Movable contact 4 Movable piece 5 Thermally responsive element (bimetal)
7 Resin case 8 Cover piece 9 Secondary battery pack 21 Fixed contact 71 Case body 72 Cover member 79 Open hole 81 Bead part 82a Projection 82b Projection

83a Bead part

83b Bead part 90 Safety circuit

Claims

A fixed piece having a fixed contact, a movable piece having a movable contact, the movable piece pressing the movable contact against the fixed contact, and the movable contact moving away from the fixed contact by being deformed as the temperature changes. In a breaker comprising a thermally responsive element that operates the movable piece as described above, and a resin case that houses the fixed piece, the movable piece and the thermally responsive element,
A breaker, wherein the resin case is integrally formed with a plate-like cover piece having a bead portion.
Of the cover piece, at least the outside of the portion where the bead portion is formed is covered with the resin case, and at least the movable contact is in contact with the cover piece when the movable contact is separated from the fixed contact. The breaker according to claim 1, wherein the breaker is provided.
The breaker according to claim 1 or 2, wherein the cover piece has a protrusion protruding inward of the resin case so as to be in contact with the movable piece.
The breaker according to claim 1 or 2, wherein the bead portion is formed so as to protrude toward an inner side of the resin case so that a part of the bead portion can come into contact with the movable piece. .
The breaker according to any one of claims 1 to 4, wherein the cover piece is always in contact with the movable piece in at least one place.
The breaker according to any one of claims 1 to 5, wherein an outer surface of the resin case has an opening that penetrates the resin case and exposes a part of the cover piece.
The said cover piece is arrange | positioned by the inner surface of the said resin case, and the said bead part protrudes toward the outer side direction of this resin case, The any one of Claim 1 thru | or 6 characterized by the above-mentioned. Breaker as described in.
The breaker according to any one of claims 1 to 7, wherein the bead portion extends along a longitudinal direction of the resin case.
The breaker according to any one of claims 1 to 8, wherein the bead portion extends along a specific direction.
A safety circuit for electrical equipment, comprising the breaker according to any one of claims 1 to 9.
A secondary battery pack comprising the breaker according to any one of claims 1 to 9.