JP6010336B2 - Breaker, safety circuit including the same, and secondary battery - 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 has been used as a protection device (safety circuit) for secondary batteries and motors of various electric devices (see FIGS. 9 and 10). 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 the same document is a case in which parts such as a fixed piece (base terminal), a movable piece (movable arm), a thermally responsive element, and a PTC thermistor are housed in a case. Used by connecting to the electrical circuit of electrical equipment.

WO2011-105175

  In the breaker disclosed in Patent Document 1, the lid member is ultrasonically welded to the case body to integrate the case, and the fixing portion is sandwiched between the front and back surfaces by the lid member (cover member) and the case body. Thus, the posture of the movable piece is fixed (see paragraphs (0032) and (0037) of the same document). In the ultrasonic welding process, stress is applied to the lid member in the direction of the case body so that an appropriate frictional force is generated between the lid member and the case body. This stress remains inside the lid member even after the welding step, and has an action of pressing the movable piece against the case body and stabilizing the posture of the movable piece with respect to the case body.

  In addition, when a breaker is mounted on a secondary battery pack or safety circuit, and when the breaker terminal is connected to the circuit, depending on the work such as welding or soldering, the lid is covered by heat transferred from the movable piece etc. The member may be exposed to high temperatures. Usually, soldering of terminals is performed quickly, so the lid member is not exposed to excessively high temperatures.For example, it is severe under conditions and inferior conditions such as soldering in high temperature atmosphere. In a difficult environment, if it takes time to solder the terminals, etc., the lid member becomes hot and the stress remaining inside the lid member is released suddenly, pressing the movable piece against the case body, The effect of residual stress that stabilizes the posture of the movable piece relative to the main body is reduced. Moreover, distortion may occur in the lid member due to the release of stress, and it may be difficult to fix the movable piece in an appropriate posture.

  When the position of the movable piece varies with such distortion of the lid member, the positional relationship between the movable contact provided at the tip of the movable piece and the fixed contact provided on the case body varies, There is a risk of affecting the contact resistance of both contacts. In addition, the change in the positional relationship between the movable contact and the fixed contact is a cause of deteriorating the temperature characteristics of the breaker. Such a problem associated with the distortion of the lid member has been regarded as a problem that appears more prominently as the size of the breaker is pursued.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a breaker capable of obtaining a stable resistance value and good temperature characteristics during energization while achieving downsizing.

  In order to achieve the above object, the present invention provides a fixed piece having a fixed contact, a movable contact at a tip, and a movable piece that presses and contacts the movable contact with the fixed contact. In 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 thermal responsive element. The movable piece has a first elastic portion that generates an elastic force for pressing the movable contact against the fixed contact, and an elastic force that abuts the case and maintains the posture of the movable piece with respect to the case. It has the 2nd elastic part which generate | occur | produces, It is characterized by the above-mentioned.

  In the present invention, the case includes a first case formed by inserting the fixed piece, and a second case attached to the first case, and the second elastic portion includes the second case and the second case. It is preferable that the movable piece abuts to bias the movable piece toward the first case.

  In this invention, the movable piece has a fixed portion that is sandwiched between the first case and the second case and fixed to the case, and the second elastic portion is formed on the fixed portion. Preferably it is.

  In this invention, the movable piece has a fixed portion that is sandwiched between the first case and the second case and fixed to the case, and the second elastic portion extends from the fixed portion. It is preferable.

  In this invention, it is preferable that the said 2nd elastic part is extended from the said fixing | fixed part independently of the said 1st elastic part.

  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 posture of the movable piece with respect to the case is appropriately maintained by the elastic force generated by the second elastic portion provided so as to be in contact with the case, separately from the first elastic portion. Thereby, it is possible to stabilize the positional relationship between the movable contact provided at the tip of the movable piece and the fixed contact provided in the case without using the action of the stress remaining in the case. Therefore, the contact resistance of both contacts during energization is reduced, and the temperature characteristics of the breaker are maintained well.

  Further, since the second elastic portion is elastically deformed, the stress generated in the peripheral region of the second elastic portion is released to the second elastic portion, so that the stress remaining in the case is relieved. That is, the second elastic portion bears a larger stress due to elastic deformation, thereby relieving the stress remaining in the case. As described above, since the stress remaining in the case is originally reduced, even when the breaker has to be mounted under severe conditions, the distortion of the case caused by the release of the residual stress can be reduced. . This makes it possible to reduce the distortion of the case while reducing the size of the breaker and to obtain a stable resistance value and good temperature characteristics during energization.

  According to the configuration in which the fixed piece is insert-molded in the first case, the second elastic portion abuts on the second case to generate an elastic force, and the movable piece is biased toward the first case. The posture of the movable piece with respect to the case is stabilized. On the other hand, since the fixed piece is insert-molded in the first case, the posture of the movable piece with respect to the fixed piece is stabilized, and the positional relationship between the movable contact and the fixed contact is further stabilized.

  Further, according to the configuration in which the second elastic portion is formed in the fixed portion that is sandwiched and fixed between the first case and the second case, the posture of the movable piece with respect to the first case and the second case is stabilized and movable. The positional relationship between the contact and the fixed contact is further stabilized.

  Moreover, according to the structure by which the 2nd elastic part is extended from the fixing | fixed part pinched | interposed and fixed by the 1st case and the 2nd case, the freedom of the form of the site | part which contact | abuts a 2nd elastic part in a 2nd case The degree can be increased. For example, a portion that contacts the second elastic portion can be provided at a location away from the fixed portion. Thereby, it becomes possible to raise the design freedom of a breaker.

  Further, according to the configuration in which the second elastic portion is extended from the fixed portion independently of the first elastic portion, the elastic deformation of the second elastic portion does not affect the posture of the first elastic portion. . Thereby, the positional relationship between the movable contact and the fixed contact is further stabilized.

  Moreover, according to the safety circuit or secondary battery pack provided with the breaker of the present invention, the safety circuit or secondary battery pack can reduce the distortion of the case and obtain a stable resistance value and good temperature characteristics when energized. 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 shows the structure of the movable piece 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 expands and shows the periphery of the 2nd elastic part of the breaker. The perspective view which shows the modification of a movable piece. The perspective view which expands and shows the periphery of the 2nd elastic part of the breaker to which the modification of the same movable piece is applied. 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, and a case 7 for housing a PTC thermistor 6. 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. And exposed from an opening 73 b formed above the resin base 71. The terminal 22 is exposed to the outside 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 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 formed 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 fixed portion 42 (corresponding to the base end of the arm-shaped movable piece 4) and a first elastic portion 43 between the movable contact 3 and the terminal 41. In the fixed part 42, the movable piece 4 is fixed by being sandwiched by the resin base 71 and the cover member 72 from the front and back sides, and the first elastic part 43 is elastically deformed, so that the movable contact 3 formed at the tip thereof is fixed. The fixed piece 2 and the movable piece 4 can be energized by being pressed and brought into contact with the contact 21 side. The resin base 71 and the cover member 72 are respectively formed with an abutting portion 74 and an abutting portion 79 (see FIG. 4) 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. The cover member 72 includes a stepped portion 77, and a contact portion 79 is formed in a region facing the contact portion 74 across the movable piece 4. 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 by pressing in the first elastic portion 43. 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 44 are formed on the lower surface of the first elastic portion 43 so as to face the thermal response 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 first elastic portion 43 through the small protrusion 44 (see FIGS. 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 portion 46, the inclined surface 47, the engaging portion 48, and the constricted portion 49 are on the opposite side of the movable contact 3 across the first elastic portion 43, that is, with respect to the first elastic portion 43. On the side. The through hole 45 is provided on the center line in the longitudinal direction of the movable piece 4. The slope 47 is formed continuously along the 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 fixed portion 42 of the movable piece 4. The fixed portion 42 is formed wider than the first 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 fixed portion 42 becomes a portion larger than the cross-sectional area in the first 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 fixed portion 42 and the terminal 41 on the side opposite to the first elastic portion 43 with the fixed portion 42 interposed therebetween. The width dimension of the constricted part 49 (the length dimension of the movable piece 4 in the short direction, the same applies hereinafter) is preferably set equal to or less than the width dimension of the first elastic part 43, but at least the fixed part 42 and the terminal 41 should just be set smaller than the width dimension. 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 first elastic portion 43 of the movable piece 4 is pushed up by the reverse warp operation of the thermal response element 5 at the desired temperature and returns to the original state by the elastic force of the first elastic portion 43, the material and shape of the thermal response element 5 Is not particularly limited, but a rectangle is desirable from the viewpoint of productivity and efficiency of reverse warping operation, and a rectangle close to a square is desirable in order to efficiently push up the first elastic portion 43 while being small. . Examples of the material of the thermally responsive element 5 include, for example, white, brass, 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.

  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 a housing portion 73 for housing the thermally responsive element 5 and the PTC thermistor 6, openings 73 a and 73 b for housing the movable piece 4, and the like. Note that the edges of the thermal reaction element 5 and the PTC thermistor 6 incorporated in the resin base 71 are brought into contact with each other by a frame formed inside the storage portion 73 and are guided when the thermal reaction element 5 is reversely warped. The

  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 corresponds to the through hole 45, is formed in an oval shape in plan view, 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 portions 75 are provided at two locations along a direction perpendicular to the longitudinal direction of the movable piece 4. In the present embodiment, due to the presence of the window 76, a part of the side wall of the resin base 71 is formed in a shape corresponding to the constricted portion 49 of the movable piece 4 and constitutes the positioning portion 75. That is, the positioning part 75 is interposed in a part cut out in the vicinity of the constricted part 49 and reinforces the resin base 71.

  The cover member 72 has a stepped portion 77 protruding from its inner wall surface into a shape corresponding to the stepped bent portion 46 of the movable piece 4, and an inclined surface 78 (see FIG. 5) formed on the stepped portion 77. The slope 78 corresponds to the slope 47 of the movable piece 4 and is continuously formed along a direction perpendicular to the longitudinal direction of the movable piece 4.

  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 phosphor bronze 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. To increase.

  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 storage portion 73 of the resin base 71 that stores 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 thermally responsive element 5 maintains the initial shape (before reverse warping), the fixed contact 21 and the movable contact 3 are in contact with each other, and the breaker is connected through the first elastic portion 43 of the movable piece 4 and the like. 1 is electrically connected between the two terminals 22 and 41. The first elastic part 43 of the movable piece 4 and the thermal response element 5 are in contact with each other, and the movable piece 4, the thermal response 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. If the PTC thermistor 6 is overheated due to overcharging or abnormalities, the thermal actuator 5 that has reached the operating temperature is warped in reverse, and the first elastic portion 43 of the movable piece 4 is pushed up to move with the fixed contact 21. The contact 3 is separated. 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 first 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. 2.

  FIG. 4 shows the configuration of the movable piece 4. The movable piece 4 has a second elastic part 42a. The second elastic portion 42a is curved so that the central portion of the fixed portion 42 is raised on the surface side of the movable piece 4, and is formed in a gentle arc shape in plan view. The second elastic part 42 a is not limited to the central part of the fixed part 42, but may be curved so as to partially protrude from the surface side of the movable piece 4. Moreover, you may curve so that it may protrude on the back surface side of the movable piece 4. FIG. Further, the second elastic part 42 a may be formed continuously with the first elastic part 43 in the vicinity of the root of the first elastic part 43. Even if it is such a form, the function of the 1st elastic part 43 is not prevented by presence of the 2nd elastic part 42a. The second elastic portion 42 a is elastically deformed when the fixed portion 42 is sandwiched between the cover member 72 and the resin base 71 and receives compressive stress from the front and back, and extends in the longitudinal direction of the movable piece 4. In the present embodiment, the second elastic portion 42 a is formed from the end edge to the end edge of the fixed portion 42 along the short direction of the movable piece 4 so as to be easily elastically deformed. The elastic force generated by the second elastic portion 42 a functions so as to maintain the posture of the movable piece 4 with respect to the case 7. In the present embodiment, the second elastic portion 42 a abuts on the abutting portion 79 of the cover member 72 to generate an elastic force, and the fixed portion 42 of the movable piece 4 is placed on the abutting portion 74 side of the resin base 71. By energizing (pressing the fixed part 42 against the contact part 74), the posture of the movable piece 4 is maintained. The second elastic portion 42 a may be formed along the longitudinal direction of the movable piece 4.

  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, when ultrasonic vibration is applied to either or both of the resin base 71 and the cover member 72 while the resin base 71 is pressed in the direction of the cover member 72, The contact portion between the resin base 71 and the cover member 72 (mainly the periphery 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. To do.

  FIG. 6 shows an enlarged view of the periphery of the second elastic portion 42 a after the cover member 72 is welded to the resin base 71. In the figure, the original shape of the second elastic portion 42a before welding is indicated by a broken line. When the cover member 72 is pressed in the direction of the resin base 71 from the state shown in FIG. 5B, the top portion of the second elastic portion 42 a comes into contact with the contact portion 79 of the cover member 72. When the cover member 72 is still pressed, the second elastic portion 42a is sandwiched between the contact portion 74 and the contact portion 79 and receives compressive stress, and the longitudinal direction of the movable piece 4 (the tip direction of the movable piece 4). It is elastically deformed as shown by the solid line while slightly extending.

  At the time of welding, due to the cover member 72 being pressed in the direction of the resin base 71, a corresponding compressive stress is generated in the contact portion 74, the contact portion 79, and the second elastic portion 42a. In the present embodiment, since the second elastic portion 42a is elastically deformed from the original shape indicated by the broken line to the shape indicated by the solid line, the stress generated in the contact portion 74 and the contact portion 79 is released, The stress remaining in the contact part 74 and the contact part 79 after the welding is alleviated. That is, the second elastic portion 42a bears a larger stress due to elastic deformation, thereby relieving the stress remaining in the contact portion 74 and the contact portion 79.

  As described above, according to the breaker 1 of the present embodiment, by the elastic force generated by the second elastic portion 42 a provided so as to contact the cover member 72 of the case 7 separately from the first elastic portion 43, The posture of the movable piece 4 with respect to the case 7 is properly maintained. As a result, the positional relationship between the movable contact 3 provided at the tip of the movable piece 4 and the fixed contact 21 provided in the case 7 is stabilized, and the contact resistance of both contacts during energization is reduced, The temperature characteristics of the breaker 1 are maintained well.

  Further, since the second elastic portion 42a is elastically deformed, the stress generated in the peripheral region of the second elastic portion 42a is released to the second elastic portion 42a, so that the stress remaining in the case 7 is relieved. That is, the second elastic portion 42a bears a larger stress due to elastic deformation, thereby relieving the stress remaining in the case 7. As described above, since the stress remaining in the case 7 is originally reduced, even when the breaker 1 must be mounted under severe conditions, the distortion of the case 7 caused by the release of the residual stress is reduced. be able to. Thereby, it is possible to obtain a stable resistance value and good temperature characteristics during energization by reducing the distortion of the case 7 while reducing the size of the breaker 1.

  Further, the fixed piece 2 is insert-molded on the resin base 71, the second elastic portion 42 a abuts on the cover member 72 to generate elastic force, and the movable piece 4 is urged toward the resin base 71 to move the movable piece 4. Therefore, the second elastic portion 42a urges the movable piece 4 toward the resin base 71 and presses the fixed portion 42 against the contact portion 74 of the resin base 71, thereby moving the movable piece 4 against the resin base 71. 4's posture is stabilized. On the other hand, since the fixed piece 2 is insert-molded in the resin base 71, the posture of the movable piece 4 with respect to the fixed piece 2 is stabilized, and the positional relationship between the movable contact 3 and the fixed contact 21 is further stabilized.

  Further, since the second elastic portion 42a is formed in the fixed portion 42 that is sandwiched and fixed between the resin base 71 and the cover member 72, the posture of the movable piece 4 with respect to the resin base 71 and the cover member 72 is stabilized and movable. The positional relationship between the contact 3 and the fixed contact 21 is further stabilized.

  Further, when the cover member 72 is attached to the resin base 71 and is ultrasonically welded, the tip of the protrusion 74 a of the resin base 71 is 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, at the fixed 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.

(Modification)
FIG. 7 shows a configuration of a modification of the movable piece. 4 A of movable pieces differ from the movable piece 4 shown in FIG. 4 etc. by the point which has a pair of tongue-like 2nd elastic part 42b extended from the fixing | fixed part 42. As shown in FIG. Also in this modified example, the movable piece 4 is fixed to the case 7 by the fixed portion 42 being sandwiched from both the front and back surfaces of the fixed portion 42 by the contact portion 74 and the contact portion 79.

  The pair of second elastic portions 42 b extends from the fixed portion 42 in parallel with the first elastic portion 43 with the first elastic portion 43 interposed therebetween. Between the 1st elastic part 43 and each 2nd elastic part 42b, the groove | channel 42c which penetrates the movable piece 4 in the thickness direction is formed, and the 1st elastic part 43 and each 2nd elastic part 42b are isolate | separated. . That is, each second elastic portion 42 b extends from the fixed portion 42 independently of the first elastic portion 43. Therefore, each can be deformed independently, and the elastic deformation of the first elastic portion 43 does not affect the position and posture of each second elastic portion 42b, and the elastic deformation of each second elastic portion 42b is not affected. The position and posture of the first elastic part 43 are not affected. Each of the second elastic portions 42b is raised on the surface side of the movable piece 4, and is bent stepwise, and its tip is positioned above the fixed portion 42 and the first elastic portion 43 in a side view (see FIG. 8). ). The second elastic part 42 b is not limited to a form extending from the fixed part 42 in parallel with the first elastic part 43, but may be a form extending in the short direction of the movable piece 4. Moreover, the form extended inside the through-hole 45 may be sufficient. In this embodiment, the shape of the protrusion 74a is also changed to avoid interference with the second elastic portion 42b.

  FIG. 8 is an enlarged view of the periphery of the second elastic portion 42 b after the cover member 72 is welded to the resin base 71. In the figure, the original shape of the second elastic portion 42b before welding is indicated by a broken line. When the cover member 72 is pressed in the direction of the resin base 71 from the state shown in FIG. 5B, the tip of the second elastic portion 42b contacts the back surface of the cover piece 8 that is insert-molded in the cover member 72. Touch. When the cover member 72 is still pressed, the second elastic portion 42b is pressed downward in FIG. 8 by the cover piece 8 and slightly extends in the longitudinal direction of the movable piece 4 (the tip direction of the movable piece 4). Elastically deforms as shown by the solid line.

  In order to stabilize the posture of the movable piece 4 with respect to the case 7, a configuration in which the movable piece 4 is urged and held using stress generated by elastic deformation is effective. In this modification, the movable piece 4 is biased by the elastic deformation of the second elastic portion 42b. And since the contact part of the 2nd elastic part 42b and the cover piece 8 is formed in the position away from the fixing | fixed part 42, the movable piece 4 urged | biased by the 2nd elastic part 42b is opposite in the figure. Moment is generated clockwise. This moment acts so as to press the first elastic portion 43 side of the fixed portion 42 against the contact portion 74 and press the terminal 41 side of the fixed portion 42 against the contact portion 79. Posture is stable. Even if there is a slight vertical gap between the contact portion 74, the fixed portion 42, and the contact portion 79, a clockwise moment exceeding the moment generated by the second elastic portion 42b is applied to the movable piece 4. Unless given, there is no possibility that the posture of the fixing portion 42 with respect to the case 7 will fluctuate.

  In the present modification, the posture of the movable piece 4 with respect to the case 7 is stabilized by elastically deforming the second elastic portion 42b. Therefore, the contact portion 74, the fixed portion 42, and the contact portion 79 are structurally strongly compressed. There is no need to apply stress, and therefore the stress remaining in the case 7 is relaxed. That is, the second elastic portion 42b bears a larger stress due to elastic deformation, thereby relieving the stress remaining in the case 7. As described above, since the stress remaining in the case 7 is originally reduced, even when the breaker 1 must be mounted under severe conditions, the distortion of the case 7 caused by the release of the residual stress is reduced. be able to. This makes it possible to obtain a stable resistance value and good temperature characteristics during energization.

  Further, since the second elastic portion 42b extends from the fixed portion 42 that is sandwiched and fixed between the resin base 71 and the cover member 72, the configuration of the portion of the cover member 72 that contacts the second elastic portion 42b is free. The degree can be increased. For example, in the modification, the distortion of the cover member 72 can be further suppressed by causing the second elastic portion 42b to directly contact the cover piece 8 that is insert-molded to the cover member 72. This is because the metal material constituting the cover piece 8 generally has a higher elastic coefficient than the resin material constituting the cover member 72.

  Further, since the second elastic part 42 b extends from the fixed part 42 independently of the first elastic part 43, the elastic deformation of the second elastic part 42 b affects the posture of the first elastic part 43. There is no. Thereby, the positional relationship between the movable contact 3 and the fixed contact 21 is further stabilized.

  Since the movable piece 4 and the cover piece 8 are in contact with each other via the second elastic portion 42b, the Joule heat generated by the current flowing through the movable piece 4 during the energization shown in FIG. It is possible to suppress the heat generation of the thermally responsive element 5. When the breaker 1 is applied to an electronic device such as a thin-type multifunctional mobile phone called a notebook personal computer, a tablet-type portable information terminal device, or a smart phone, fluctuations in the CPU load and brightness of the backlight of the LCD The current flowing through the movable piece 4 varies due to the variation. If the thermal responsive element 5 operates excessively sensitively to such a change in current and the breaker 1 reacts frequently, the operation of the electronic device is hindered. In the present modification, Joule heat generated in the movable piece 4 is conducted to the cover piece 8, so that it is possible to suppress the thermal responsive element 5 from operating too sensitively to the current flowing through the movable piece 4.

  The present invention is not limited to the configuration of the embodiment described above, and at least the movable piece 4 contacts the first elastic portion 43 that generates elastic force for pressing the movable contact 3 against the fixed contact 21, the case 7, and the like. The second elastic part 42a or the second elastic part 42b that contacts and generates an elastic force for maintaining the posture of the movable piece 4 with respect to the case 7 may be provided. Moreover, the structure which has the 2nd elastic part 42a and the 2nd elastic part 42b may be sufficient.

  Further, the present invention can be variously modified in addition to the above modified examples. For example, the form of the second elastic part 42a or the second elastic part 42b is a form that abuts on the case 7 and generates an elastic force for maintaining the posture of the movable piece 4 with respect to the case 7, as shown in FIG. It is not restricted to what was shown in 6. Further, the second elastic portion 42 a and the second elastic portion 42 b protrude to the back surface side of the movable piece 4 in a side view, abut against the resin base 71 and generate elastic force, and the fixing portion 42 on the cover member 72 side. The configuration may be such that the posture of the movable piece 4 is maintained by urging. In addition to the second elastic portion 42a or the second elastic portion 42b, or in place of the second elastic portion 42a or the second elastic portion 42b, the cover piece 8 is provided with a second elastic portion that contacts the movable piece 4. It may be a configuration. According to this configuration, the second elastic part provided on the cover piece 8 biases the fixed part 42 of the movable piece 4 toward the resin case 71.

  Furthermore, since the movable piece 4 formed of a plate-like metal material has elasticity by itself, a part thereof may be configured to function as a plate spring-like second elastic portion. . In this case, a space for elastically deforming the second elastic portion by bending, bending, stepping or folding a part of the movable piece 4 or forming a part of the resin base 71 in a concave shape as necessary. Or a convex portion that contacts the second elastic portion may be formed on the cover member 72. Further, in order to facilitate elastic deformation of the second elastic part, a groove or the like penetrating the movable piece 4 in the thickness direction may be formed on the periphery of the second elastic part. Also by such a second elastic portion, the movable piece 4 is biased toward the resin base 71 or the cover member 72 and the posture thereof is stabilized, and the relative position of the movable contact 3 with respect to the fixed contact 21 is stabilized.

  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, the slope 47, the engaging part 48, and the constriction part 49, However, either of these structures or All may be abolished. For example, when the through hole 45 is discarded, the projection 74a of the resin base 71 is also discarded. Further, when the stepped portion 46 and the slope 47 are eliminated, the movable piece 4 is formed in a flat shape, and the contact portion 74 of the resin base 71 and the contact portion 79 of the cover member 72 are flat. In this configuration, by eliminating the step bending portion 46 and the slope 47, the size of the movable piece 4 and the resin base 71 in the longitudinal direction can be reduced, and the breaker 1 can be further downsized. The step bending portion 46 and the slope 47 of the movable piece 4 may be provided outside the resin base 71 as necessary. Further, when the engaging portion 48 and the constricted portion 49 are eliminated, the movable piece 4 is formed to have a uniform width from the fixed portion 42 to the terminal 41, and accordingly, the shape of the positioning portion 75 of the resin base 71 is also changed. Be changed.

  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 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.

  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. 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 configuration of the breaker is simplified, and further miniaturization can be achieved.

  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.

  Further, the breaker 1 of the present invention can be widely applied to the secondary battery pack shown in FIG. 9, the safety circuit shown in FIG.

DESCRIPTION OF SYMBOLS 1 Breaker 2 Fixed piece 3 Movable contact 4 Movable piece 5 Thermally responsive element 7 Case 21 Fixed contact 42a Resin welding part (resin adhesion part)
71 Resin base (first case)
72 Cover member (second case)
92 Resin reservoir

Claims (7)

A fixed piece having a fixed contact;
A movable piece at the tip, and a movable piece that presses and contacts the movable contact with 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,
The movable piece has a first elastic portion that generates an elastic force for pressing the movable contact against the fixed contact, and an elastic force that abuts the case and maintains the posture of the movable piece with respect to the case. have a second elastic portion for generating,
The case has a first case in which the fixed piece is embedded, and a second case attached to the first case,
The second elastic portion protrudes toward the second case, abuts against the second case and elastically deforms, and biases the movable piece toward the first case . The movable piece has a fixed portion that is sandwiched between the first case and the second case and fixed to the case.
2. The breaker according to claim 1, wherein the second elastic portion is formed to be curved so that a part of the fixing portion protrudes toward the second case . The breaker according to claim 2, wherein the second elastic portion is formed from an end edge to an end edge of the fixed portion along a short direction of the movable piece . A fixed piece having a fixed contact;
A movable piece at the tip, and a movable piece that presses and contacts the movable contact with 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,
The case has a first case in which the fixed piece is embedded, and a second case attached to the first case,
The movable piece has a first elastic portion that generates an elastic force for pressing the movable contact against the fixed contact, and an elastic force that abuts the case and maintains the posture of the movable piece with respect to the case. A second elastic part that is generated; and a fixing part that is sandwiched between the first case and the second case and is fixed to the case.
The second elastic unit, wherein formed in the fixed part, the second casing and in contact with, features and to Lube Reka that urges the movable piece on the side of the first case. A fixed piece having a fixed contact;
A movable piece at the tip, and a movable piece that presses and contacts the movable contact with 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,
The case has a first case in which the fixed piece is embedded, and a second case attached to the first case,
The movable piece has a first elastic portion that generates an elastic force for pressing the movable contact against the fixed contact, and an elastic force that abuts the case and maintains the posture of the movable piece with respect to the case. A second elastic part that is generated; and a fixing part that is sandwiched between the first case and the second case and is fixed to the case.
The second elastic portion, said first elastic portion, wherein the to Lube Reka that is extended from the fixing part independently.   A safety circuit for an electric device comprising the breaker according to any one of claims 1 to 5.   A secondary battery pack comprising the breaker according to any one of claims 1 to 5.

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