JP6085107B2 - Breaker, safety circuit including the same, and secondary battery circuit - Google Patents

Description

  The present invention relates to a small breaker built in a secondary battery pack or the like of an electric device.

  Conventionally, a breaker (thermal protector) has been used as a protection device for secondary battery packs and motors of various electric devices (see FIGS. 8 and 9 to be described later). When the temperature of the secondary battery during charging / discharging rises excessively, or when an abnormality occurs such as when an overcurrent flows through a motor or the like equipped in a device such as an automobile or home appliance, Cut off current to protect secondary batteries and motors. A breaker used as a safety circuit of such a protective device is required to operate accurately following a temperature change and have a stable resistance value when energized in order to ensure the safety of the device. .

  In addition, when the breaker is used as a protection device for a secondary battery or the like installed in an electric device such as a thin-type multifunctional mobile phone called a notebook personal computer, a tablet-type portable information terminal device, or a smartphone, the above-described case is used. In addition to ensuring safety, miniaturization is required. In particular, in recent portable information terminal devices, users have a strong desire for miniaturization (thinning), and devices newly released by each company are designed to be small in order to ensure superiority in design. The tendency to be remarkable is remarkable. Against this background, breakers that are mounted together with secondary batteries as one component of portable information terminal devices are also strongly required to be further miniaturized.

  The breaker is provided with a thermally responsive element that operates according to a temperature change and conducts or cuts off a current. Patent Document 1 discloses a breaker to which a bimetal is applied as a thermally responsive element. Bimetal is an element that is formed by laminating two types of plate-like metal materials having different coefficients of thermal expansion, and controls the conduction state of the contact by changing the shape in accordance with a temperature change. The circuit breaker shown in the same document includes a fixed piece (base terminal), a movable piece (movable arm), a thermally responsive element, a PTC thermistor and the like housed in a resin case. Is used by being connected to an electric circuit of an electric device.

WO2011 / 105175 gazette

  When the circuit breaker disclosed in Patent Document 1 seeks to be thin, the distance (contact gap) between the fixed contact and the movable contact in the open circuit (see FIG. 3) tends to be short. However, if the distance between the fixed contact and the movable contact in the open circuit becomes too short, there is a possibility that the current cannot be sufficiently interrupted, and it is not easy to ensure safety. In particular, if the thickness of the thermo-responsive element is set to be thin in order to reduce the thickness, the force that pushes the tip of the movable piece when the thermo-actuating element undergoes reverse warping becomes weak, so the distance between the fixed contact and the movable contact during open circuit Is difficult to maintain, and there is a risk that the current cannot be reliably interrupted. In addition, when a thermally responsive element having a small curvature coefficient is used to reduce the thickness, the amount by which the tip of the movable piece is pushed up decreases, resulting in the same problem.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a breaker that can realize downsizing while ensuring the safety of an electric device by reliably cutting off an electric current at the time of an open circuit. To do.

  In order to achieve the above object, a breaker according to the present invention includes a fixed piece having a fixed contact, an elastic portion that is elastically deformed, and a movable contact at a tip of the elastic portion, and the movable contact is used as the fixed contact. A movable piece that is pressed and brought into contact; a thermally responsive element that operates the movable piece so that the movable contact is separated from the fixed contact by being deformed as the temperature changes; and the fixed piece, the movable piece, and the thermal responsive element A breaker including a case for accommodating an element, wherein the thermally responsive element protrudes toward the movable piece and contacts the movable piece and / or the case during thermal deformation to actuate the movable piece It is what has.

  In this invention, it is preferable that the first protrusions are formed at both end portions of the thermally responsive element in the extending direction of the elastic portion.

  In this invention, the thermally responsive element includes a guided portion guided by a frame formed in the case at the time of deformation, and a direction parallel to a direction in which the elastic portion extends from the guided portion. It is preferable that the first protrusion is formed on the extension portion.

  In this invention, it is preferable that the movable piece is formed with a second protrusion that protrudes toward the thermally responsive element at a position in contact with the first protrusion.

  In the present invention, it is preferable that the first protrusion protrudes in a hemispherical shape.

  In addition, a safety circuit for an electric device according to the present invention includes the breaker.

  In addition, a secondary battery pack according to the present invention includes the breaker.

  According to the breaker of the present invention, the first protrusion provided on the thermally responsive element abuts the movable piece or the like when the thermal responsive element is reversely warped to operate the movable piece. The amount of pushing up of the part increases, and the distance between the fixed contact and the movable contact in the open circuit can be increased. Therefore, the circuit breaker can be reduced in size, and the current can be surely cut off when the circuit is opened, thereby ensuring the safety of the electric device.

  In addition, according to the configuration in which the first protrusions are formed at both ends of the thermally responsive element in the extending direction of the elastic portion, the first protrusions are formed at both ends having a large amount of displacement when the thermally responsive element is thermally deformed. Since it is provided, the amount by which the tip of the movable piece is pushed up when the current is interrupted can be further increased.

  In addition, according to the configuration in which the entire length of the thermally responsive element is extended by the extended portion extended from the guided portion, and the first protrusion is provided in the extended portion, the amount of displacement of the first protrusion during thermal deformation is reduced. It can be made even larger. Thereby, it is possible to further increase the push-up amount of the tip of the movable piece during the reverse warp deformation of the thermally responsive element.

  Further, according to the configuration in which the movable piece has the second protrusion protruding toward the heat-responsive element, and the second protrusion is in contact with the first protrusion, the movable piece becomes the heat-responsive element when the heat-responsive element is deformed. It is possible to further increase the amount of push-up of the tip of the movable piece when the thermally responsive element is reversely warped while advancing the contact timing, thereby further enhancing the safety of the electric device.

  In addition, according to the configuration in which the first protrusion protrudes in a hemispherical shape, the contact portion between the movable piece and the first protrusion follows the reverse warp deformation of the thermally responsive element while maintaining an appropriate contact area. The contact state between the two is maintained. As a result, a weak current can be continuously passed between the movable piece and the thermally responsive element, and various functions required by the electrical equipment can be accommodated.

  In addition, according to the safety circuit or the secondary battery pack provided with the breaker of the present invention, it is possible to ensure the safety of the electric device by reliably cutting off the current at the time of the open circuit while reducing the size of the breaker.

The assembly perspective view which shows the structure of the breaker by one 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. Sectional drawing which shows the modification of the breaker. The assembly perspective view which shows another modification of the breaker. Sectional drawing of the modification. The assembly perspective view which shows another modification of the same 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 provided with the breaker of this invention.

  A breaker according to an embodiment of the present invention will be described with reference to the drawings. 1 to 3 show the configuration of the breaker. 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, a PTC (Positive Temperature Coefficient) thermistor 6, , A fixed piece 2, a movable piece 4, a thermally responsive element 5, a case 7 for housing a PTC thermistor 6, and the like. The case 7 includes a resin base (first case) 71, a cover member (second case) 72 attached to the upper surface of the resin base 71, and the like.

  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 is embedded in the resin base 71 by insert molding. ing. A terminal 22 electrically connected to the outside is formed at one end of the fixed piece 2, and a PTC thermistor 6 is placed in the vicinity of the other end. The PTC thermistor 6 is placed on convex dowels (small protrusions) formed at three locations in the vicinity of the other end of the fixed piece 2. The fixed contact 21 is formed at a position facing the movable contact 3 by cladding, plating, coating, or the like of a conductive material such as silver, nickel, nickel-silver alloy, copper-silver alloy, gold-silver alloy. The resin base 71 is exposed from a part of the opening 73 formed above. The terminal 22 protrudes outward from one end of the resin base 71.

  The movable piece 4 is formed in an arm shape symmetrical to the center line in the longitudinal direction by pressing a metal plate equivalent to the fixed piece 2. As a material of the movable piece 4, a material mainly composed of phosphor bronze equivalent to the fixed piece 2 is preferable. In addition, a conductive elastic material such as copper-titanium alloy, white or brass may be used. A terminal 41 that is electrically connected to the outside is formed at one end in the longitudinal direction of the movable piece 4 and protrudes outward from the resin base 71. In the present embodiment, the movable piece 4 is bent in a crank shape at a step bending portion 46 outside the case 7 in order to make the height of the terminal 22 of the fixed piece 2 and the terminal 41 of the movable piece 4 uniform. A movable contact 3 is formed at the other end of the movable piece 4 (corresponding to the tip of the arm-shaped movable piece 4). The movable contact 3 is made of the same material as the fixed contact 21 and is joined to the tip of the movable piece 4 by a technique such as welding. In the present application, in the movable piece 4, the surface to which the movable contact 3 is joined (that is, the lower surface in FIG. 1) is the back surface, and the opposite surface is the front surface. It is described as a surface. The same applies to the front and back surfaces of other components such as the thermally responsive element 5. The movable piece 4 includes a fixed portion 42 (corresponding to a base end portion of the arm-shaped movable piece 4) and an elastic portion 43 between the movable contact 3 and the terminal 41. The fixed portion 42 corresponds to the base of the elastic portion 43, and is sandwiched between the resin base 71 and the cover member 72 in the fixed portion 42, the movable piece 4 is cantilevered, and the elastic portion 43 is elastically deformed, whereby the distal end portion thereof The movable contact 3 formed in the above is pressed and brought into contact with the fixed contact 21, so that the fixed piece 2 and the movable piece 4 can be energized. The resin base 71 and the cover member 72 are respectively formed with an abutment portion 74 and an abutment portion 79 that abut against the fixed portion 42 of the movable piece 4 and hold the fixed portion 42 in a fixed state. In the present embodiment, a contact portion 74 is formed in a region extending from the outer edge of the housing portion 73 of the resin base 71 to the outer wall of the resin base 71. In the cover member 72, a contact portion 79 is formed in a region facing the contact portion 74 with the movable piece 4 interposed therebetween. The movable piece 4 is accommodated in the resin base 71 from the back side where the movable contact 3 is provided. The fixed portion 42 contacts the contact portion 74 of the resin base 71 on the back surface, and contacts the contact portion 79 of the cover member 72 on the front surface. The movable piece 4 is sandwiched from the front and back surfaces of the fixed portion 42 by the contact portion 74 and the contact portion 79 and is fixed to the case 7.

  The movable piece 4 is curved or bent at the elastic portion 43 by pressing. The degree of bending or bending is not particularly limited as long as the thermally responsive element 5 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 point, and the like.

  The thermally responsive element 5 is made of a composite material such as bimetal or trimetal, and has a rectangular main body portion 50 and first protrusions 53a and 53b formed at the end of the main body portion 50 in plan view. The main body 50 has an initial shape that is curved in an arc shape when viewed from the side. When the operating temperature reaches the operating temperature due to overheating, the curved shape is reversely warped with snap motion, and the shape is restored when the temperature falls below the return temperature due to cooling. The initial shape of the thermoresponsive element 5 can be formed by pressing. As long as the elastic portion 43 of the movable piece 4 is pushed up by the reverse warping operation of the thermal response element 5 at a desired temperature and returns to the original state by the elastic force of the elastic portion 43, the material and shape of the thermal response element 5 are particularly limited. Although not intended, the main body 50 is preferably rectangular in plan view from the viewpoint of productivity and the efficiency of reverse warping operation, and in order to efficiently push up the elastic portion 43 while being small, it is a rectangle close to a square. desirable. Examples of the material of the thermally responsive element 5 include, for example, white, brass, and stainless steel including copper-nickel-manganese alloy or nickel-chromium-iron alloy on the high expansion side and iron-nickel alloy on the low expansion side. A material obtained by laminating two kinds of materials made of various alloys having different coefficients of thermal expansion is used in combination according to the required conditions.

  When the energization of the fixed piece 2 and the movable piece 4 is interrupted by the reverse warping operation of the thermal response element 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 resin base 71 and the cover member 72 constituting the case 7 are molded from a resin such as flame retardant polyamide, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polybutylene terephthalate (PBT) having excellent heat resistance. Yes. The resin base 71 is formed with an opening 73 for accommodating the fixed piece 2, the movable piece 4, the thermally responsive element 5, the PTC thermistor 6, and the like. Inside the opening 73, a frame 75a and a frame 75b are formed. The edge of the PTC thermistor 6 incorporated in the resin base 71 is in contact with the frame 75a. Further, the end edge of the main body portion 50 of the thermally responsive element 5 is brought into contact with the frame 75 b and is guided when the thermally responsive element 5 is deformed. That is, the frame 75b functions as a guide portion that guides the thermal response element 5 when the thermal response element 5 is deformed, and the edge of the main body 50 of the thermal response element 5 functions as a guided portion that is guided by the frame 75b. To do.

  As shown in FIG. 1, a cover member 72 is formed on the upper surface of the resin base 71 so as to close the opening 73 of the resin base 71 that houses the fixed piece 2, the movable piece 4, the thermally responsive element 5, the PTC thermistor 6, and the like. Installed. The resin base 71 and the cover member 72 are joined by, for example, ultrasonic welding.

  As shown in FIGS. 1 to 3, the thermally responsive element 5 includes first protrusions 53a and 53b, and the movable piece 4 includes second protrusions 44a and 44b. The first protrusion 53a and the second protrusion 44a come into contact with each other, and the first protrusion 53b and the second protrusion 44b come into contact with each other, so that the heat-responsive element 5 is deformed through the first protrusion 53a and the second protrusion 44a and 44b. Is transmitted to the elastic part 43 of the movable piece 4.

  The first protrusions 53 a and 53 b are formed so as to protrude from the surface of the thermally responsive element 5 toward the movable piece 4. The first protrusions 53a and 53b are formed one by one at both ends of the thermally responsive element 5 in the extending direction of the elastic portion 43 (longitudinal direction of the breaker 1). That is, the first protrusion 53a is formed at the end of the elastic part 43 on the base side (near the fixed part 42), and the first protrusion 53b is formed at the end of the elastic part 43 on the tip side (near the movable contact 3). ing. Each of the first protrusions 53a and 53b is formed so as to protrude in a hemispherical shape. A plurality of first protrusions 53 a and 53 b may be formed at each of both ends of the thermally responsive element 5. In the present application, hemispherical means a shape constituting a part of a spherical shell.

  The second protrusions 44 a and 44 b are formed so as to protrude from the back surface of the movable piece 4 toward the thermally responsive element 5. The second protrusions 44a and 44b overlap at least partly with the first protrusions 53a and 53b in plan view, and are formed at positions where they abut against the first protrusions 53a and 53b. That is, the second protrusion 44 a is formed at the base end of the elastic portion 43, and the second protrusion 44 b is formed at the tip end of the elastic portion 43. The first protrusion 53a and the second protrusion 44a are disposed so as to face each other, and both come into contact with each other. Further, the first protrusion 53b and the second protrusion 44b are disposed so as to face each other, and both come into contact with each other. Each of the second protrusions 44a and 44b is formed so as to protrude in a hemispherical manner, like the first protrusions 53a and 53b. A plurality of second protrusions 44a and 44b may also be formed.

  In the present embodiment, the first protrusion 53a and the second protrusion 44a and the first protrusion 53b and the second protrusion 44b are always in contact from the conductive state shown in FIG. 2 to the shut-off state shown in FIG. The protrusion amount of each protrusion is set. If the first protrusion 53a and the second protrusion 44a and the first protrusion 53b and the second protrusion 44b are in contact with each other and push up the tip of the movable piece 4 in the blocking state shown in FIG. 3, the conduction shown in FIG. In the state, the first protrusion 53a and the second protrusion 44a and the first protrusion 53b and the second protrusion 44b may be separated from each other.

  FIG. 2 shows the operation of the breaker 1 in a normal charge or discharge state. In a normal charging or discharging state, the thermal responsive element 5 maintains the initial shape (before reverse warping), the fixed contact 21 and the movable contact 3 come into contact with each other, and the breaker 1 passes through the elastic portion 43 of the movable piece 4. The terminals 22 and 41 are electrically connected. The elastic part 43 of the movable piece 4 and the thermal responsive element 5 are in contact with each other via the second protrusions 44a and 44b and the first protrusions 53a and 53b, and the movable piece 4, the thermal responsive element 5, the PTC thermistor 6 and the fixed part. The piece 2 is conductive 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 substantially larger than the amount flowing through the fixed contact 21 and the movable contact 3. It can be ignored.

  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 abnormality, the thermal actuator 5 that has reached the operating temperature is warped in reverse, and the elastic portion 43 of the movable piece 4 is pushed up so that the fixed contact 21 and the movable contact 3 Are separated from each other. At this time, the current flowing between the fixed contact 21 and the movable contact 3 is cut off, and a slight leakage current is passed through the second protrusions 44a and 44b and the first protrusions 53a and 53b, and the thermally responsive element 5 and the PTC thermistor. 6 will flow through. Since the PTC thermistor 6 continues to generate heat as long as such a leakage current flows, the resistance value is drastically increased while maintaining the thermally actuated element 5 in the reverse warped state, so that the current is a path between the fixed contact 21 and the movable contact 3. There is only the above-described slight leakage current (which constitutes 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 heat generation of the PTC thermistor 6 is also stopped, and the thermal actuator 5 returns to the return temperature and is restored to the original initial 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.

  In the present embodiment, since the first protrusions 53a and 53b provided on the thermally responsive element 5 abut against the movable piece 4 when the thermal responsive element 5 is deformed in reverse warp, the movable piece 4 is operated. The amount by which the tip of the movable piece 4 is pushed up increases, and the distance between the fixed contact 21 and the movable contact 3 in the open circuit can be increased. Therefore, the circuit breaker 1 can be reduced in size, and the current can be reliably interrupted when the circuit is opened, thereby ensuring the safety of the electric device.

  In addition, since the first protrusions 53a and 53b are formed at both ends of the thermal response element 5 in the extending direction of the elastic portion 43, the first projections 53a and 53b are formed at both ends with a large displacement when the thermal response element 5 is thermally deformed. One protrusion 53a, 53b is disposed. Thereby, the pushing-up amount of the front-end | tip part of the movable piece 4 at the time of electric current interruption can be increased further.

  Further, the movable piece 4 has second protrusions 44a and 44b that protrude toward the heat-responsive element 5, so that the second protrusion 44a contacts the first protrusion 53a and the second protrusion 44b contacts the first protrusion 53b. Therefore, when the thermal response element 5 is deformed, the tip of the movable piece 4 is pushed up when the thermal reaction element 5 is deformed in the reverse direction while the timing at which the movable piece 4 contacts the thermal response element 5 is advanced. The amount can be further increased, and the safety of the electrical equipment can be further enhanced.

  Further, since the first protrusions 53a and 53b and the second protrusions 44a and 44b protrude in a hemispherical shape, the second protrusions 44a and 44b of the movable piece 4 and the heat-responsive element follow the reverse warp deformation of the heat-responsive element 5. While the contact portion with the first projections 53a and 53b of the 5 moves, the contact state between the two is maintained while maintaining an appropriate contact area. As a result, a weak current can be continuously passed between the movable piece 4 and the thermally responsive element 5, and various functions required by the electrical equipment can be accommodated.

(Modification 1)
FIG. 4 shows a breaker 1 </ b> A as a modification of the breaker 1. The breaker 1A is different from the breaker 1 in that the second protrusions 44a and 44b are eliminated from the movable piece 4. In the breaker 1 </ b> A, the first protrusions 53 a and 53 b formed on the thermally responsive element 5 come into contact with the back surface of the elastic portion 43 of the movable piece 4. At the time of reverse warping deformation of the thermally responsive element 5, the first protrusion 53 b pushes up the tip of the elastic portion 43, and the fixed contact 21 and the movable contact 3 are separated from each other as in the state shown in FIG. Become.

  Also in this breaker 1A, the first protrusions 53a and 53b provided on the thermal response element 5 abut against the movable piece 4 when the thermal response element 5 is deformed in reverse warpage, and thus the movable piece 4 is operated. The amount by which the tip of the movable piece 4 is pushed up increases, and the distance between the fixed contact 21 and the movable contact 3 in the open circuit can be increased. Therefore, the circuit breaker 1A can be reduced in size, and the current can be surely cut off when the circuit is opened to ensure the safety of the electric device. In addition, since the hemispherical first protrusions 53a and 53b are in contact with the back surface of the flat elastic portion 43, even if the relative position and posture of the thermally responsive element 5 with respect to the movable piece 4 vary, The contact state between the one protrusion 53a, 53b and the elastic portion 43 is stable.

(Modification 2)
5 and 6 show a breaker 1B as another modified example of the breaker 1. FIG. The breaker 1 </ b> B is different from the breaker 1 in that a first extending portion 51 is provided on one end side of the thermally responsive element 5, and a first protrusion 53 a is formed on the first extending portion 51. Along with this, the position of the second protrusion 44a is also moved to the fixed portion 42 side so that the second protrusion 44a contacts the first protrusion 53a.

  The first extending portion 51 extends from the main body portion 50 of the thermally responsive element 5 to the fixed portion 42 side. Further, at a position corresponding to the first extending portion 51 of the resin base 71, the resin base 71 is recessed from the frame 75b to the fixed piece 42 side so as to avoid interference with the first extending portion 51. A retracting portion 76 is formed. The retracting portion 76 is retracted slightly larger than the first extending portion 51. That is, the clearance between the first extending portion 51 of the thermally responsive element 5 and the side wall of the retracting portion 76 is set to be larger than the clearance between the main body portion 50 of the thermally responsive element 5 and the frame 75 b of the resin base 71. Yes. Therefore, even if the thermally responsive element 5 moves inside the frame 75 b, the edge of the first extending portion 51 and the side wall of the retracting portion 76 do not contact each other. As a result, the first extending portion 51 does not interfere with a part of the resin base 71 when the heat responsive element 5 is deformed.

  The first extending portion 51 is formed in an intermediate portion of the end edge of the main body portion 50 on the fixed portion 42 side. The width dimension of the first extension part 51 (dimension in the short direction of the breaker 1) is set smaller than the width dimension of the main body part 50. Thereby, the area of the upper surface of the resin base 71, that is, the bonding area between the resin base 71 and the cover member 72 can be increased, both can be firmly bonded, and the robustness of the breaker 1 can be improved. The first extending portion 51 is not limited to a form extending in a rectangular shape in a plan view as shown in FIG. 5, and may be a form extending in a triangular shape or an arc shape in a plan view.

  In the vicinity of the fixed portion 42 of the movable piece 4, there are no components such as the fixed contact 21 and the movable contact 3. Therefore, the configuration in which the first extending portion 51 is provided in the thermally responsive element 5 and the retracting portion 76 is provided in the resin base 71 is different from the configuration in which the extending portion and the retracting portion are provided on the movable contact 3 side. There is little tendency to prevent downsizing.

  In this breaker 1B, the entire length of the thermally responsive element 5 is extended by the first extending portion 51 extending from the main body portion 50, which is a guided portion, to the fixed portion 42 side of the movable piece 4, and the first extension thereof. Since the first protrusion 53a is provided in the projecting portion 51, the displacement amount of the first protrusion 53b on the opposite side to the first protrusion 53a can be further increased when the thermally responsive element 5 is deformed. Thereby, the pushing-up amount of the front-end | tip part of the movable piece 4 at the time of reverse curvature deformation | transformation of the thermoresponsive element 5 can be increased further. In general, the provision of the first protrusion 53a on the thermally responsive element 5 may change the rigidity distribution of the thermally responsive element 5 and may slightly affect the thermal deformation of the thermally responsive element 5. In the present modification, since the first protrusion 53 a is formed in the first extension portion 51, the influence of the presence of the first protrusion 53 a on the thermal deformation of the main body portion 50 can be suppressed. Thereby, the reverse warp deformation of the main body 50 is generated at a desired temperature, and the current can be quickly cut off.

(Modification 3)
FIG. 7 shows a breaker 1 </ b> C as another modification of the breaker 1. The breaker 1 </ b> C is different from the breaker 1 </ b> B in that a second extending portion 52 is provided on the other end side of the thermally responsive element 5, and a first protrusion 53 b is formed on the second extending portion 52. Accordingly, the second protrusion 44b is moved to the movable contact 3 side so that the second protrusion 44b contacts the first protrusion 53b.

  The second extending portion 52 extends from the main body portion 50 of the thermally responsive element 5 to the movable contact 3 side. Further, at a position corresponding to the first extending portion 51 of the resin base 71, the resin base 71 is recessed from the frame 75b to the fixed piece 42 side so as to avoid interference with the first extending portion 51. A retracting portion 77 is formed. The clearance between the second extending portion 52 and the side wall of the retracting portion 77 is the same as the clearance between the first extending portion 51 and the side wall of the retracting portion 76, and thus the description thereof is omitted.

  In this breaker 1C, the entire length of the thermally responsive element 5 is extended by the second extending portion 52 extending from the main body portion 50, which is a guided portion, to the movable contact 3 side of the movable piece 4, and the second extension thereof. Since the first protrusion 53b is provided in the projecting portion 52, the displacement amount of the first protrusion 53b when the heat responsive element 5 is deformed can be further increased. Thereby, the pushing-up amount of the front-end | tip part of the movable piece 4 at the time of reverse curvature deformation | transformation of the thermoresponsive element 5 can be increased further.

  Further, similarly to the first protrusion 53a in the breaker 1B, the first protrusion 53b is formed in the second extending part 52, thereby suppressing the influence of the presence of the first protrusion 53b on the thermal deformation of the main body part 50. it can. Thereby, the reverse warp deformation of the main body 50 is generated at a desired temperature, and the current can be quickly cut off.

  In addition, this invention is not restricted to the structure of the said embodiment, At least the fixed piece 2, the movable piece 4, the thermal response element 5, and the case 7 are provided, and the thermal response element 5 is the 1st protrusion 53a or 53b. As long as it has.

  Further, the present invention can be variously modified in addition to the above modified examples. For example, in the breaker 1 shown in FIG. 1 or the like, the breaker 1A shown in FIG. 4, the breaker 1B shown in FIG. 5 or the like, or the breaker 1C shown in FIG. 7, either the first protrusion 53a or the first protrusion 53b One may be omitted. This is because only the other first protrusion can provide an action / effect of increasing the amount of pushing up of the tip of the movable piece 4. Similarly, in the breaker 1 shown in FIG. 1 and the like, the breaker 1B shown in FIG. 5 and the like, and the breaker 1C shown in FIG. 7, one of the second protrusion 44a and the second protrusion 44b may be omitted. Good. Further, in the breaker 1B shown in FIG. 5 and the like and the breaker 1C shown in FIG. 7, both the second protrusion 44a and the second protrusion 44b may be omitted. Furthermore, in the breaker 1C shown in FIG. 7, the first extending portion 51 may be omitted. In this case, the first protrusion 53a is moved to or omitted from the main body 50 of the thermally responsive element 5.

  The present invention can also be applied to a breaker as disclosed in, for example, JP-A-2003-297204. That is, in the configuration in which a part of the case such as the protrusion 13 is in contact with the end portion of the thermally responsive element 5 in the publication, the first protrusion 53a and / or the first 1 The protrusion 53b may be formed. In this case, as in the publication, the protrusion 13 is not limited to the structure formed on the lid 11 (the cover member 72 in the present invention), and may be formed on the resin base 71 of the present invention. A PTC thermistor may be provided separately.

  The shape of the second protrusion 44a is not limited to a hemispherical shape, and the top of the second protrusion 44a extends along the longitudinal direction and / or the short direction of the breaker as long as it does not substantially affect the elastic deformation of the elastic portion 43. The shape may be flat. In this case, an area that functions effectively to increase the amount of push-up of the distal end portion of the movable piece 4 in the second protrusion 44a increases. Therefore, the relative relationship between the second protrusion 44a and the first protrusion 53a is increased. Even if the position shift occurs, the action and effect of increasing the amount of pushing up of the tip of the movable piece 4 can be obtained. Therefore, when the movable piece 4 and the thermally responsive element 5 are incorporated in the resin base 71, relative positioning between the two can be easily performed. The shape of the second protrusion 44b is the same as described above. Furthermore, the shape of the first protrusions 53a and / or 53b is the same as described above as long as it does not substantially affect the reverse warp deformation of the thermally responsive element 5.

  Further, in FIG. 1 and the like, the movable piece 4 has a step bent portion 46 exposed to the outside from the case 7, but the step bent portion 46 may be accommodated inside the case 7. Good. In this case, the projecting amount of the movable piece 4 from the case 7 can be reduced to further reduce the size of the breaker 1 and the like. Further, the stepped portion 46 may be omitted from the movable piece 4. Further, in order to facilitate positioning when the movable piece 4 is loaded on the resin base 71, a protruding portion that protrudes toward the movable piece 4 is provided on the contact portion 74 of the resin base 71. A through hole corresponding to the protruding portion may be provided respectively. According to this configuration, the protrusion is engaged with the through hole, so that the movable piece 4 can be easily and accurately positioned with respect to the resin base 71, and the tip of the protrusion is placed on the cover member 72 and the ultrasonic wave. By welding by vibration or the like, the strength and rigidity of the case 7 can be increased.

  Moreover, the joining method of the resin base 71 and the cover member 72 is not limited to ultrasonic welding, and can be appropriately 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 case 7 is not limited to the form constituted by the resin base 71 and the cover member 72, and may be constituted by a single part, or may be a form in which another part is added. Good. Similarly, the case 7 may be configured to have a first case and a second case that are different from the resin base 71 and the cover member 72.

  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. The present invention can also be applied to a form having a first contact and a second contact at both ends of a movable piece as disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-115246. In this case, a PTC thermistor may be separately provided between the first electrode and the second electrode.

  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. In this case, the terminal 41 side and the movable contact 3 side may be fixed by welding or the like.

  Further, the breaker 1 of the present invention can be widely applied to secondary battery packs, safety circuits for electric devices, and the like. FIG. 9 shows the secondary battery pack 100. The secondary battery pack 100 includes a secondary battery 101 and a breaker 1 provided in the output terminal circuit of the secondary battery 101. FIG. 10 shows a safety circuit 102 for electrical equipment. The safety circuit 102 includes a breaker 1 in series in the output circuit of the secondary battery 101.

DESCRIPTION OF SYMBOLS 1 Breaker 1A Breaker 1B Breaker 1C Breaker 2 Fixed piece 3 Movable contact 4 Movable piece 5 Thermally responsive element 7 Case 44a 2nd protrusion 44b 2nd protrusion 50 Main part (guided part)
51 1st extension part 52 2nd extension part 53a 1st protrusion 53b 1st protrusion 71 Resin base (case)
100 Secondary battery pack 101 Secondary battery 102 Safety circuit

Claims (6)

A fixed piece having a fixed contact;
A movable piece having an elastic part that is elastically deformed and a movable contact at a tip of the elastic part, and pressing the movable contact against the fixed contact;
A thermally responsive element that operates the movable piece so that the movable contact is separated from the fixed contact by being deformed with a temperature change;
In the breaker comprising the fixed piece, the movable piece, and a case for accommodating the thermally responsive element,
It said heat responsive element, have a first protrusion for actuating protrude the movable piece at the time of thermal deformation and / or said case and abutting against movable Dohen on a side of the movable piece,
The thermally responsive element extends in a direction parallel to a guided portion guided by a frame formed in the case at the time of deformation and a direction in which the elastic portion extends from the guided portion. Having an extended portion,
The first protrusion is formed in the extension part .   2. The breaker according to claim 1, wherein the first protrusions are formed at both ends of the thermally responsive element in a direction in which the elastic portion extends. 3. The breaker according to claim 1 , wherein the movable piece is formed with a second protrusion that protrudes toward the thermally responsive element at a position where the movable piece comes into contact with the first protrusion . 4. The breaker according to any one of claims 1 to 3, wherein the first protrusion protrudes in a hemispherical shape . A safety circuit for electrical equipment, comprising the breaker according to any one of claims 1 to 4. A secondary battery pack comprising the breaker according to any one of claims 1 to 4.

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