JP2014102955A - Breaker, safety circuit and secondary battery circuit including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain good temperature characteristics by preventing rusting of a thermally-actuated element in a breaker used as a protection device of a secondary battery or the like.SOLUTION: A movable piece 4 has a terminal 41 projecting to the outside of a case 7, an elastic part 43 which generates elastic force for pressing a movable contact against a fixed contact, and an abutting part 42 abutting on the case 7 between the terminal 41 and the elastic part 43. A resin base 71 constituting the case 7 has an abutting part 74 abutting on the abutting part 42 of the movable piece 4. A gap between the abutting part 42 of the movable piece 4 and the abutting part 74 of the resin base 71 is filled with a resin 74h to enhance adhesion between the movable piece 4 and the case 7. Thus, moisture or the like is prevented from entering the inside of the case 7 to prevent rusting of a thermally-actuated element 5, thereby maintaining a normal thermal deformation operation.

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 is used as a protection device (safety circuit) for secondary batteries and motors of various electric devices. 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. Breakers used as such protective devices operate accurately following temperature changes (having good temperature characteristics) and have stable resistance when energized to ensure the safety of the equipment. It is required to be.

  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 breaker shown in this document is a fixed piece (base terminal), a movable piece (movable arm), a thermal actuator, a PTC thermistor, etc. housed in a resin case. Is used by being connected to an electric circuit of an electric device.

  In the breaker disclosed in Patent Document 1, the lid member (cover member) is ultrasonically welded to the case body (resin base) to integrate the resin case, and the movable piece is a fixed portion (contact portion). In this case, the movable member is fixed between the front and back surfaces by the lid member and the case body (see paragraphs (0032) and (0037) of the same document).

WO2011 / 105175 gazette

  In Patent Document 1, since the case main body and the lid member constituting the resin case are both formed of a resin material, they are firmly bonded to each other by ultrasonic welding, and a high bonding strength and airtightness (sealing) between them. Property). On the other hand, the movable piece which comprises an electric circuit with a fixed piece is formed with the metal material. Since the bond between the metal material and the resin material is inferior to the bond between the resin materials, the bond strength between them decreases, or a slight gap generated between the movable piece and the case body and the lid member. Airtightness may be reduced. For this reason, depending on the extremely inferior use environment, moisture may enter the internal space, and rust may be generated in the metal constituting the thermal response element, etc., and the normal thermal deformation operation of the thermal response element is hindered by the rust. There was a fear.

  In recent years, with the aim of improving production efficiency, a form in which the breaker is directly mounted on the circuit board has been studied. Furthermore, reflow soldering is used to connect the breaker terminal and the circuit board lead. Use is under consideration. However, the flux may enter through a slight gap generated between the movable piece, the case main body, and the lid member, which contributes to the rust described above.

  The present invention has been made in order to solve the above-mentioned problems, and improves the bonding strength and airtightness between the movable piece and the case, and prevents the heat-responsive element and the like from rusting, thereby preventing normal heat of the heat-responsive element. An object of the present invention is to provide a breaker capable of maintaining a deformation operation and obtaining good temperature characteristics.

  In order to achieve the above object, a breaker of the present invention includes a fixed piece having a fixed contact, a movable contact, a movable piece that presses the movable contact against the fixed contact, and a temperature change. A breaker comprising: a thermally responsive element that operates the movable piece so that the movable contact is separated from the fixed contact by being deformed; and a case that houses the fixed piece, the movable piece, and the thermally responsive element. The piece has an abutting portion that abuts the case, and a filler is filled in a gap between the abutting portion and the case.

  In this invention, it is preferable that the case has a through hole extending from the outside to the contact portion.

  In this invention, it is preferable that a concave portion filled with the filler is formed on the inner surface of the case.

  In this invention, it is preferable that at least a part of the concave portion is continuously formed in a direction perpendicular to a direction in which the movable piece extends.

  In the present invention, the filler is preferably an epoxy resin or an acrylic resin.

  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 airtightness between the movable piece and the case is enhanced by filling the gap between the contact portion and the case with the filler. Therefore, the bonding strength in the region from the movable piece to the case is increased, and extremely high sealing performance is obtained. This prevents moisture and flux from entering the inside of the case, prevents rust from occurring on metal parts such as thermal actuators, maintains normal thermal deformation of the thermal actuators, and is good Temperature characteristics can be obtained.

  In addition, according to the configuration in which the case has a through-hole extending from the outside to the contact portion, the filler can be filled from the through-hole after incorporating a part such as a movable piece into the case. Simplification can be achieved and production efficiency can be increased.

  Moreover, according to the structure by which the recessed part with which a filler is filled is formed in the inner surface of a case, the resin material with which the case was filled flows along a recessed part. As a result, the resin material can be spread all over the surface (hymen) of the contact portion, the bonding strength in the region from the movable piece to the case can be further increased, and extremely high sealing performance can be obtained.

  In addition, according to the configuration in which the concave portion is continuously formed in at least a part in a direction perpendicular to the direction in which the movable piece extends, the sealing property of the case is further enhanced, and the inside of the case is increased. Intrusion of moisture and the like can be prevented.

  In addition, according to the configuration filled with epoxy resin or the like, the fluidity of the resin material before curing is high, so that the epoxy resin can be easily distributed to every corner of the surface of the contact portion, and the sealing property of the case is further improved. Enhanced. In addition, after the epoxy resin material filled without any gaps is cured, it is firmly bonded to the abutting part of the movable piece and the case, so that the sealing of the case is further enhanced, and moisture and the like enter the case. Can be prevented.

  Moreover, according to the safety circuit or the secondary battery pack provided with the breaker of the present invention, the safety circuit or the secondary battery pack in which safety is ensured by excellent temperature characteristics can be manufactured.

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. The perspective view which fractures | ruptures a part of resin base and shows the structure of the resin base applied to the breaker. Sectional drawing which shows a mode that a movable piece is integrated in a resin base and a cover member is mounted | worn in time series. Sectional drawing which shows the process of filling the resin material inside a case. Sectional drawing which shows the process in which the filled resin material hardens | cures and a case is sealed. Sectional drawing which shows 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 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, a cover piece 8, and the like.

  The fixing piece 2 is formed by pressing a metal plate mainly composed of phosphor bronze or the like (other metal plate such as copper-titanium alloy, white or brass) and embedded in the resin base 71 by insert molding. It is. A terminal 22 electrically connected to an external circuit is formed at one end of the fixed piece 2, and a PTC thermistor 6 is placed in the vicinity of the other end 23. The PTC thermistor 6 is placed on convex dowels (small protrusions) 23 a formed at three locations in the vicinity of the other end 23 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 73b 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 plate-like metal material. As a material of the movable piece 4, a material mainly composed of phosphor bronze or the like 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 electrically connected to an external circuit is formed at one end in the longitudinal direction of the movable piece 4 and is exposed to the outside from the resin base 71. 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 movable piece 4 has a contact portion 42 (corresponding to a base end of the arm-like movable piece 4 and a portion embedded in the case 7) and an elastic portion 43 between the movable contact 3 and the terminal 41. . The contact portion 42 has a protrusion 42 a that contacts the resin base 71 and the cover member 72 between the terminal 41 and the elastic portion 43 and protrudes in a wing shape in the short direction of the movable piece 4. The elastic part 43 extends from the contact part 42 to the movable contact 3 side. The movable piece 4 is fixed by being sandwiched by the resin base 71 and the cover member 72 at the abutting portion 42 from the front and back sides, and the elastic portion 43 is elastically deformed, whereby the movable contact 3 formed at the tip thereof is a fixed contact. The fixed piece 2 and the movable piece 4 can be energized by being pressed and brought into contact with the side 21.

  The resin base 71 and the cover member 72 are respectively formed with an abutting portion 74 and an abutting portion 79 that abut against the abutting portion 42 of the movable piece 4 and hold the abutting 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. The contact portion 74 constitutes a part of the bottom wall (inner bottom surface) of the case 7 in FIG. 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 contact portion 79 constitutes a part of the top wall (inner top surface) of the case 7 in FIG. The contact 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 contact portion 42 by the contact portion 74 and the contact portion 79 and fixed to the case 7. In this embodiment, since the contact part 42 has the protrusion part 42a which protrudes in the shape of a wing in the transversal direction of the movable piece 4, the contact part 74 and the contact part of the case 7 have a wide and large area. 79, the movable piece 4 is firmly 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. In addition, a pair of small protrusions (contact portions) 44 are formed on the lower surface of the elastic portion 43 so as to face the heat-responsive element 5. The small protrusion 44 and the thermal response element 5 come into contact with each other, and the deformation of the thermal response element 5 is transmitted to the elastic portion 43 through the small protrusion 44 (see FIGS. 1, 2, and 3).

  Further, the movable piece 4 has a through hole 45 that penetrates in the thickness direction of the movable piece 4 and through which the protrusion 74a of the resin base 71 is inserted, a step bent portion 46 formed in a crank shape, and a step bent portion 46. Part of the movable piece 4 is cut off in the short direction perpendicular to the longitudinal direction of the movable piece 4 and the formed slope 47, the pair of engaging portions 48 engaged with the positioning portion 75 of the resin base 71. A constricted portion 49 is formed. The through hole 45, the step bent part 46, the slope 47, the engaging part 48, and the constricted part 49 are provided on the opposite side of the movable contact 3 with the elastic part 43 interposed therebetween, that is, on the terminal 41 side with respect to the elastic part 43. ing. The through hole 45 is provided on the center line in the longitudinal direction of the movable piece 4 at the constricted portion 49. The slope 47 is formed continuously along the short direction of the movable piece 4. The engaging portions 48 are provided at two locations along the short direction of the movable piece 4.

  The through hole 45 is formed in the contact portion 42 of the movable piece 4. The contact portion 42 is formed wider than the elastic portion 43 in the short direction of the movable piece 4. Thereby, the cross-sectional area perpendicular to the longitudinal direction of the movable piece 4 in the contact portion 42 becomes a portion larger than the cross-sectional area in the elastic portion 43. Further, the through hole 45 is formed in an oval shape that is long in the lateral direction of the movable piece 4 in plan view (as viewed in the thickness direction of the movable piece 4).

  The engaging portion 48 is formed at the end edge of the constricted portion 49 on the terminal 41 side. The constricted portion 49 is disposed between the contact portion 42 and the terminal 41 on the side opposite to the elastic portion 43 with the contact portion 42 interposed therebetween. The width dimension of the constricted portion 49 (the length dimension in the short direction of the movable piece 4, the same applies hereinafter) is preferably set equal to or less than the width dimension of the elastic portion 43, but at least the contact portion 42. And it should just be set smaller than the width dimension of the terminal 41. The constricted part 49 in this embodiment has a function as the second elastic part in the above-mentioned Patent Document 1, and absorbs an external force and an impact applied to the terminal 41 and appropriately maintains the position of the movable contact 3. .

  The thermally responsive element 5 has an initial 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 reversely warped with snap motion, and 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, a rectangular shape is desirable from the viewpoint of productivity and efficiency of reverse warping operation, and it is desirable that the rectangular shape is close to a square in order to efficiently push up the elastic portion 43 while being small. 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 laminate of two types of materials having different coefficients of thermal expansion made of various alloys such as steel is used in combination according to the required conditions. As described above, when rust is generated in the thermal response element 5, the physical properties of the metal constituting the thermal response element 5 change, so that the reverse warpage deformation does not occur even when the operating temperature is exceeded, and the normal current generated by the breaker There is a possibility that the blocking function is disturbed. Therefore, in the breaker 1 of the present embodiment, the sealing performance of the case 7 is enhanced and rusting of the thermally responsive element 5 is prevented.

  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 material and shape are not particularly limited as long as these properties are not impaired. In the present embodiment, a ceramic sintered body containing barium titanate, strontium titanate or calcium titanate is used. In addition to the ceramic sintered body, a so-called polymer PTC in which conductive particles such as carbon are contained in a polymer may be used.

  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. A material other than the resin may be applied as long as characteristics equal to or higher than those of the above-described resin can be obtained. The resin base 71 is formed with a housing portion 73 for housing the thermally responsive element 5, the PTC thermistor 6, and the like, and openings 73 a and 73 b for housing the movable piece 4. Note that the edges of the movable piece 4, the thermally responsive element 5, and the PTC thermistor 6 incorporated in the resin base 71 are in contact with each other by a frame formed inside the storage portion 73. It will be guided at the time.

  The resin base 71 has a projection 74a inserted into the through hole 45 of the movable piece 4, a pair of positioning portions 75 for positioning the movable piece 4, and a terminal 41 for exposing the movable piece 4 to the outside. A window 76 is provided. The protrusion 74 a is formed in a shape corresponding to the through hole 45 and reinforces the resin base 71. The height of the projection 74a, that is, the projection amount is set to be larger than the thickness of the movable piece 4, and a concave portion corresponding to the top of the projection 74a is provided on the back surface of the cover member 72 as necessary. The positioning portion 75 is provided in a shape corresponding to the constricted portion 49 of the movable piece 4. That is, the positioning portion 75 is interposed in a portion cut out in the vicinity of the constricted portion 49, reinforces the resin base 71, and is welded to the contact portion 79 of the cover member 72 to increase the rigidity and strength of the case 7. .

  A cover piece 8 is embedded in the cover member 72 by insert molding. The cover piece 8 is formed by pressing a metal plate mainly composed of the above-described phosphor bronze or the like or a metal plate such as stainless steel. As shown in FIGS. 2 and 3, the cover piece 8 abuts on the upper surface of the movable piece 4 as appropriate, restricts the movement of the movable piece 4, and the rigidity and strength of the case 7 as a casing as a result of the cover member 72. Contributes to the downsizing of the breaker 1

  As shown in FIG. 1, the cover member 72 is disposed on the upper surface of the resin base 71 so as to close the opening 73 a 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. It is attached to. The resin base 71 and the cover member 72 are joined by, for example, ultrasonic welding.

  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, and the movable piece 4, the thermal responsive element 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 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 interrupted, and a slight leakage current flows through the thermal actuator 5 and the PTC thermistor 6. 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.

  FIG. 4 shows an enlarged view of the contact portion 74 of the resin base 71 in which the fixed piece 2 is embedded and its periphery. The contact portion 74 is formed from the end edge of the storage portion 73 to the window 76 formed at the end edge of the resin base 71. The contact portion 74 is different from the upper step portion 74b on which the protrusion 74a is formed, the slope portion 74c inclined corresponding to the slope 47 of the step bending portion 46 of the movable piece 4, and the upper step portion 74b across the slope portion 74c. A lower step portion 74d disposed in the lower portion, and a recess portion 74e formed in the lower step portion 74d. The recess 74e is formed on the inner surface of the resin base 71 over the entire width of the opening 73a. That is, the recess 74e is formed continuously from one end to the other end in the short direction of the movable piece 4 (width direction perpendicular to the direction in which the elastic portion 43 extends).

  In the recess 74e, a through hole 74f that penetrates from the outer surface to the inner surface of the resin base 71 is formed. The through hole 74 f allows the external space of the breaker 1 to communicate with the space defined by the recess 74 e and the abutting portion 42 of the movable piece 4. As will be described later, the recess 74e is filled with a resin (filler) 74h to improve the airtightness of the case 7. The number, position, size, and shape of the through holes 74f are not particularly limited as long as the resin material 74g can be injected and flowd smoothly, that is, filled.

  FIGS. 5A and 5B show in time series how the movable piece 4 is incorporated in the resin base 71 and the cover member 72 is attached and welded. The movable piece 4 is guided into the openings 73 a and 73 b of the resin base 71 and incorporated into the resin base 71. At this time, as shown in FIG. 1, the positioning portions 75 are engaged with the engaging portions 48 on both sides of the constricted portion 49 formed on the movable piece 4, and the protrusion 74 a of the resin base 71 is formed in the through hole 45. It is inserted. Further, in addition to the protrusion 74a being inserted into the through hole 45, the engagement of the pair of engaging portions 48 and the pair of positioning portions 75 restricts the rotation of the movable piece 4 with respect to the resin base 71. Is easily done.

  In this temporary alignment stage, it is not necessary that the movable piece 4 is accurately positioned with respect to the resin base 71. Further, the movable piece 4 is placed on the resin base 71 so as to be finally aligned in a later process, and is not fixed. The positions, shapes, dimensions, and the like of the openings 73a and 73b and the protrusions 74a of the resin base 71 are such that it is easy to guide the movable piece 4 from the position where provisional alignment is performed to the fixed position where it is completely positioned. It is formed in a similar shape to the corresponding part of the movable piece 4.

  After the movable piece 4 is incorporated into the resin base 71 as shown in FIG. 5A, the cover member 72 is attached to the resin base 71. The cover member 72 is mounted on the resin base 71 while positioning the movable piece 4 by inserting the stepped portion 77 into the opening 73a of the resin base 71 and pressing the stepped portion 77 against the stepped bent portion 46 of the movable piece 4. Is done.

  As shown in FIG. 5B, when the cover member 72 is pressed in the direction of the resin base 71 (indicated by the white arrow in the figure), the slope 47 of the movable piece 4 and the slope 78 of the cover member 72 come into contact with each other. . Since the inclined surface 47 and the inclined surface 78 are continuously formed along the direction perpendicular to the longitudinal direction of the movable piece 4, the movable piece is still pressed when the cover member 72 is pressed in the direction of the resin base 71. The four slopes 47 are pushed (biased) by the slope 78 of the cover member 72 in the longitudinal direction of the movable piece 4. As a result, the direction of the force is changed by the inclined surfaces 78 and 47, and the entire movable piece 4 is pushed and moved in the longitudinal direction, that is, the arrow A direction where the fixed piece 2 exists. At this time, the pair of engaging portions 48 disposed facing the slope 47 and the pair of positioning portions 75 disposed facing the slope 78 are brought into contact with each other and engaged. As a result, the movable piece 4 that has been provisionally aligned by the protrusion 74 a and the like is accurately positioned with respect to the resin base 71. That is, the error at the time of temporary alignment that occurs when the movable piece 4 is assembled with the resin base 71 is reduced, and the positioning error of the movable piece 4 with respect to the resin base 71 is substantially reduced by the positioning of the resin base 71. It can be limited to the extent of dimensional error at the time of manufacture of the engaging part 48 of the part 75 and the movable piece 4.

  When the cover member 72 is attached to the resin base 71 and is ultrasonically welded, the tips of the protrusions 74a of the resin base 71 are brought into contact with and joined to the inner wall surface of the cover member 72. Accordingly, the movable piece 4 is firmly joined from above and below by the resin base 71 and the cover member 72 around the through hole 45, that is, in the contact portion 42. Thereby, the movable piece 4 is fixed at a fixed position (position where it should be) with respect to the resin base 71. Even after the cover member 72 is welded to the resin base 71 and the movable piece 4 is fixed, the inclined surface 47 and the inclined surface 78 remain in contact with each other, and the movable piece 4 continues to be pushed in the direction of arrow A. Accordingly, the positioning portion 75 and the engaging portion 48 maintain the engaged state, and the position and posture of the movable piece 4 with respect to the resin base 71 are maintained normally.

  When ultrasonic vibration is applied to either one or both of the resin base 71 and the cover member 72 while the cover member 72 is attached to the resin base 71 and the resin base 71 is pressed in the direction of the cover member 72, the resin base 71 The contact portion between 71 and the cover member 72 (mainly the peripheral portion of the resin base 71 and the cover member 72) is welded by frictional heat, and the resin base 71 and the cover member 72 are integrated to form the case 7. At this time, the contact portion 74 of the resin base 71 is joined to the back surface of the contact portion 42 of the movable piece 4 and the contact portion 79 of the cover member 72 is joined to the surface of the contact portion 42 of the movable piece 4 by welding. .

  FIG. 6 shows the breaker 1 in which the resin base 71 and the cover member 72 are welded by ultrasonic welding or the like. In the breaker 1 having a structure in which the resin base 71 and the cover member 72 are welded with the movable piece 4 interposed therebetween, if variations occur in the atmospheric temperature and the pressing force during welding, the contact portion 74 of the resin base 71 and the movable piece It is difficult to completely connect the four abutting portions 42 with no gaps in all contact areas, and a slight gap may be formed between them. Further, as shown in FIG. 6A, since the recessed portion 74e is formed in the lower step portion 74d of the contact portion 74, a gap corresponding to the depth dimension of the recessed portion 74e is generated in that region.

  Therefore, in the breaker 1 of the present embodiment, as shown in FIG. 6B, the top and bottom of the breaker 1 is reversed and the liquid resin material 74g is injected from the through hole 74f using the syringe 99 or the like. . At this time, the recess 74e functions as a flow path for the resin material 74g, and also functions as a resin reservoir for storing the resin material 74g that has flowed in. Accordingly, the injected resin material 74g flows through the recess 74e into the recess 74e and the gap between the contact portion 42 and the contact portion 74, and becomes a resin 74h after being cured to be integrated with the resin base 71. , An element constituting a part of the case 7. That is, the cured resin 74 h is formed in a thin layer along the inner frame of the window 76. As a result, as shown in FIGS. 7A and 7B, a gap formed between the contact portion 74 of the resin base 71 and the contact portion 42 of the movable piece 4 and a recess 74 e of the contact portion 74. The space defined by the contact portion 42 of the movable piece 4 is filled with the resin 74h, and the gap between the contact portion 74 and the contact portion 42 is sealed. The resin material 74g also flows into the gap between the edge of the abutting portion 42 of the movable piece 4 and the inner wall of the opening 73a of the resin base 71 and functions as the cured resin 74h, and the gap is also sealed. The

  The resin material 74g injected from the through hole 74f is preferably a liquid adhesive such as a thermosetting epoxy resin having a low viscosity and excellent fluidity. Resin can be distributed to every corner such as a gap formed between the contact portion 74 of the resin base 71 and the contact portion 42 of the movable piece 4. This is because the bonding strength and sealing performance with the contact portion 42 can be increased. Therefore, as long as sufficient fluidity is obtained, other resin materials such as an adhesive such as an acrylic resin may be used. Moreover, in the breaker 1 of this embodiment, as shown in FIG.7 (b), since the recessed part 74e is continuously formed from the one end to the other end in the transversal direction of the movable piece 4, resin The material 74g spreads over every corner of the full width of the contact portion 42 of the movable piece 4, and the bonding strength and the sealing performance between the contact portion 74 of the resin base 71 and the contact portion 42 of the movable piece 4 are improved.

  In addition, since the epoxy resin filled later has a different component or molecular structure from the resin constituting the resin base 71, the finished product of the breaker 1 is appropriately disassembled, and using a loupe, magnifier, microscope, etc. The trace can be confirmed.

  As described above, according to the breaker 1 of the present embodiment, the resin 74h is filled in the gap between the contact portion 42 of the movable piece 4 and the contact portion 74 of the resin base 71, so that the movable piece 4 and the resin The airtightness between the base 71 and the base 71 is improved. Therefore, the bonding strength in the region from the movable piece 4 to the resin base 71 is increased, and extremely high sealing performance can be obtained for the case 7. As a result, it is possible to prevent moisture and flux from entering the inside of the case 7 and to prevent rust from being generated on the metal parts such as the heat responsive element, and to maintain the normal heat deformation operation of the heat responsive element 5. Good temperature characteristics can be obtained.

  Further, since the resin base 71 has a through hole 74f that extends from the outside of the case 7 to the contact portion 42 of the movable piece 4, after the parts such as the movable piece 4 are assembled in the case 7, the resin material 74g is introduced from the through hole 74f. It can be filled, the manufacturing process of the breaker 1 can be simplified, and the production efficiency can be increased.

  Further, since the recess 74e filled with the resin 74h is formed on the inner surface of the resin base 71, the resin material 74g filled in the case 7 flows along the recess 74e. Thereby, the resin material 74g can be spread over every corner of the gap between the abutting portion 42 of the movable piece 4 and the abutting portion 74 of the resin base 71, and the bonding strength of the region from the movable piece 4 to the resin base 71 can be increased. Is further improved, and extremely high sealing performance is obtained.

  Further, since the recess 74e is formed continuously in the width direction of the movable piece 4 (that is, the direction perpendicular to the direction in which the elastic portion 43 extends) in the lower step portion 74d of the resin base 71, the case 7 Can be further improved, and moisture and the like can be prevented from entering the case 7.

  In addition, since the epoxy resin having high fluidity before curing is applied as the filler, the resin can be easily distributed to every corner of the surface of the contact portion, and the sealing performance of the case 7 is further enhanced. Further, since the resin material 74g filled without gaps is firmly bonded to the contact portion 42 of the movable piece 4 and the resin base 71 as the resin 74h after curing, the sealing performance of the case 7 is further improved, and the inside of the case 7 is improved. Intrusion of moisture into the water can be prevented.

  In the present embodiment, ribs 77a are formed on the stepped portion 77 of the cover member 72 (see FIG. 5A). The ribs 77 a are formed so as to protrude toward the movable piece 4 along both lateral edges of the stepped portion 77 along the short direction of the breaker 1. The resin constituting the rib 77a once melts when the resin base 71 and the cover member 72 are ultrasonically welded, and then remains between the stepped portion 77 and the movable piece 4, thereby improving the sealing performance between the two. Accordingly, the resin material 74g that has flowed into the gap between the contact portion 42 of the movable piece 4 and the contact portion 79 of the cover member 72 is blocked to prevent the resin material 74g from flowing out of the case 7. The position and number of the ribs 77a are not limited to the form shown in FIG. For example, instead of the rib 77a shown in FIG. 5A or in addition to the rib 77a, the rib 77a may be formed on the side of the storage portion 73 with respect to the through hole 74f. According to such a configuration, the resin material 74 g can be prevented from flowing into the storage portion 73.

  Further, if the resin material 74 g that has flowed into the gap between the contact portion 42 of the movable piece 4 and the contact portion 74 of the resin base 71 flows into the storage portion 73, there is a risk of hindering deformation of the thermally responsive element 5. Therefore, while controlling the injection amount of the resin material 74g, a concave portion that functions as a resin reservoir portion may be separately provided in the upper step portion 74b or the slope portion 74c of the contact portion 74 as necessary. In this case, a part of the protruding portion 42a of the movable piece 4 may be bent toward the upper step portion 74b or the slope portion 74c and inserted or fitted into the recess. In such a configuration, the positioning accuracy of the movable piece 4 can be further increased, and further, the resin material 74g that has flowed into the concave portion is cured, so that the movable piece 4 is firmly bonded to a part of the protruding portion 42a. The movable piece 4 can be firmly fixed. Further, by appropriately providing a space between the protrusion 74a and the through hole 45, the space may function as a resin reservoir, and the resin material 74g may be prevented from flowing into the storage portion 73. As described above, the number, position, size, and shape of the recesses 74e that function as the resin reservoirs depend on the flow characteristics of the resin material 74g and the mode of the contact portion 42, the contact portion 74, and the contact portion 79. It may be determined as appropriate.

(Modification)
FIG. 8 shows a breaker 1 </ b> A that is a modification of the breaker 1. The breaker 1A is different from the breaker 1 in that a pair of through holes 42b are formed in the abutting portion 42 of the movable piece 4, and a recess 79a is formed in a region inside the rib 77a in the abutting portion 79 of the cover member 72. Is different.

  The through holes 42 b are formed on both sides in the width direction of the movable piece 4 across the through holes 74 f of the resin base 71, and communicate the recess 74 e of the resin base 71 with the recess 79 a of the cover member 72. Through the through hole 42 b, the resin material 74 g injected from the through hole 74 f of the resin base 71 flows into the gap between the contact portion 42 of the movable piece 4 and the contact portion 79 of the cover member 72. The number, position, size, and shape of the through holes 42b are not particularly limited as long as the resin material 74g can flow smoothly. In addition, the number, position, size, and shape of the concave portions 79a that function as the resin reservoirs are also appropriately determined according to the flow characteristics of the resin material 74g and the form of the contact portions 42, the contact portions 74, and the contact portions 79. do it.

  The recess 79 a is continuously formed over the entire width of the movable piece 4 at the contact portion 79 of the cover member 72. The recess 79a is filled with the resin material 74g flowing from the through hole 42b, and fills the gap between the contact portion 42 of the movable piece 4 and the contact portion 79 of the cover member 72 as the cured resin 79b. According to this modified example, the resin material 74g is quickly and more reliably filled on both the front and back surfaces of the abutting portion 42 of the movable piece 4, and after curing, as the resin 74h, the abutting portion 42 and the cover of the movable piece 4 are covered. Since it is firmly bonded to the member 72, the sealing property of the case 7 is further enhanced, and the entry of moisture and the like into the case 7 can be prevented. In addition, since the resin filled in the through hole 42b integrates the resin on the resin base 71 side and the resin on the cover member 72 side, the coupling between the contact portion 42 of the movable piece 4 and its peripheral region Strength is increased.

  In addition, this invention is not restricted to the structure of the said embodiment, The resin 74h should just be filled with the clearance gap between the contact part 42 and the case 7 of the movable piece 4 at least. Accordingly, the through hole 74f is eliminated from the resin base 71, and the resin material 74g is injected from the gap between the contact portion 42 of the movable piece 4 and the contact portion 74 of the resin base 71 in the window 76 (the base of the terminal 41). The structure to harden may be sufficient. The same applies to the gap between the contact portion 42 of the movable piece 4 and the contact portion 79 of the cover member 72. Further, a through hole from the outside of the cover member 72 to the contact portion 42 of the movable piece 4 may be formed. The through hole in this case may be formed through the cover piece 8 or may be formed by bending in the direction of the terminal 41 while avoiding the cover piece 8.

  Moreover, the recessed part 74e is not restricted to the shape shown by FIG. 4 etc., You may be formed in the narrow groove shape in the contact part 74. FIG. In this case, for example, it may be a narrow groove extending in a herringbone shape in plan view from the through hole 42b toward the edge of the resin base 71 and branching. Alternatively, the recess 74e may be eliminated from the resin base 71, and the gap between the contact portion 42 of the movable piece 4 and the contact portion 74 of the resin base 71 may be filled with the resin 74h. The same applies to the recess 79a of the cover member 72.

  Further, the resin 74 h filled in the gap between the abutting portion 42 of the movable piece 4 and the case 7 is not limited to the form that is injected after the resin base 71 and the cover member 72 are welded. For example, the resin 74h is a liquid or gel (glue) adhesive that is filled in the contact portion 74 of the resin base 71 or the contact portion 42 of the movable piece 4 before the movable piece 4 or the like is incorporated into the resin base 71. The form which the agent or filler hardened | cured may be sufficient. In this case, the adhesive or filler to be filled may have a higher viscosity than the epoxy resin described above. Further, the adhesive or filler is not limited to the form in which the contact part 74 or the contact part 42 is filled, but may be a form in which the adhesive or filler is applied to the contact part 74 or the contact part 42. The same applies to the resin 79b.

  Further, in a structure in which a part of the fixed piece 2 is welded to the case 7, a structure in which a resin is filled in a gap between the fixed piece 2 and the case 7 may be employed. Furthermore, in a structure in which other metal parts such as a cover piece constituting the breaker are extended from the storage part inside the case and a part thereof is welded to the case, the part to be welded to the case is filled with resin. May be. That is, the boundary of each part in the region extending from the storage part inside the case to the outside is configured by a form in which the resin material is filled without gaps around the metal material, or a form in which the resin materials are bonded without gaps, etc. And the structure where the whole accommodating part is sealed from the exterior of a case is preferable.

  Further, in place of or in addition to the concave portion 74e of the resin base 71, a concave portion communicating with the through hole 74f or the like may be formed in the contact portion 42 of the movable piece 4, and the concave portion 79a of the cover member 72 may be formed in the concave portion 79a of the cover member 72. Alternatively, or in addition to the recess 79a, the contact portion 42 of the movable piece 4 may be formed with a recess communicating with the through hole 42b or the like.

  Moreover, in FIG. 1 etc., the movable piece 4 is a form which has the structure of the through-hole 45, the step bending part 46, and the constriction part 49, However, Any or all of these structures may be abolished. . For example, when the through hole 45 is discarded, the projection 74a of the resin base 71 is also discarded. Moreover, when the step bending part 46 is abolished, the terminal 41 becomes a flat shape. In this configuration, by eliminating the step bending portion 46, the longitudinal dimension of the movable piece 4 and the resin base 71 can be reduced, and the breaker 1 can be further reduced in size. Further, when the constricted portion 49 is eliminated, the movable piece 4 is formed to have a uniform width from the contact portion 42 to the terminal 41, and the shape of the positioning portion 75 of the resin base 71 is changed accordingly. As described above, the shapes of the contact portion 42 of the movable piece 4, the contact portion 74 of the resin base 71, the contact portion 79 of the cover member 72, and the like are not limited to those shown in FIG. is there. Further, the shapes of the thermally responsive element 5 and the storage portion 73 are not limited to those shown in FIG. 1 and can be changed as appropriate.

  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 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 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.

  Moreover, the structure which forms the movable piece 4 and the thermally responsive element 5 integrally by forming the movable piece 4 with a bimetal or a trimetal etc. may be sufficient. In this case, the heat transfer part is formed in the integrated movable piece, the structure of the breaker is simplified, and further miniaturization can be achieved. Further, in the present embodiment, the self-holding circuit by the PTC thermistor 6 is provided, but the present invention can be applied even in a form in which such a configuration is omitted.

  Further, as shown in JP-A-2005-203277, the movable piece 4 is structurally separated into the terminal 41 side and the movable contact 3 side in the contact portion 42 or the vicinity thereof. The invention may be applied. Further, the arm terminal and the movable arm 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.

1, 1A Breaker 2 Fixed piece 3 Movable contact 4 Movable piece 5 Thermally responsive element 7 Case 8 Cover piece 21 Fixed contact 42 Contact part 74e Recess 74f Through hole 74h Resin (filler)
79a Recess 79b Resin (filler)
101 Secondary battery 102 Safety circuit

Claims (7)

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 case that houses the fixed piece, the movable piece and the thermally responsive element
The movable piece has a contact portion that contacts the case,
A breaker in which a filler is filled in a gap between the contact portion and the case.   The breaker according to claim 1, wherein the case has a through hole extending from the outside to the contact portion.   The breaker according to claim 1 or 2, wherein a recess filled with the filler is formed on an inner surface of the case.   The breaker according to claim 3, wherein at least a part of the recess is continuously formed in a direction perpendicular to a direction in which the movable piece extends.   The breaker according to any one of claims 1 to 4, wherein the filler is an epoxy resin or an acrylic resin.   A safety circuit for an electric device comprising the breaker according to any one of claims 1 to 5.   A secondary battery circuit comprising the breaker according to any one of claims 1 to 5.

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