JP2015053193A - Direct-current breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure excellent durability while reducing on-resistance of a contact.SOLUTION: A breaker comprises: a fixed contact metal plate 4 in which a fixed contact 5 is fixed to a base metal plate; a movable contact metal plate 6 in which a movable contact 7, arranged at a position opposite to the fixed contact 5, is fixed to an elastic arm 6A of the base metal plate; and a bi-metal 8 which presses the elastic arm 6A so as to move the movable contact 7 away from the fixed contact 5. The movable contact 7 and the fixed contact 5 of the breaker are configured such that one of the contacts is a nickel-silver alloy contact 31 and the other contact is a silver contact 32. The silver contact 32 is provided, on a face opposite to the nickel-silver alloy contact 31, with a mixed layer 34 made of silver containing nickel. The nickel-silver alloy contact 31 is provided by plating the surface of the base metal plate with a nickel-silver alloy. Alternatively, the nickel-silver alloy contact 31 is provided in such a way that the nickel-silver alloy is welded or pressure-welded onto the surface of the base metal plate.

Description

  The present invention relates to a DC breaker that cuts off a current when the temperature becomes higher than a preset temperature, and more particularly, to a DC breaker that is optimal for incorporating a device built in a battery pack or the like.

  The breaker is incorporated in a battery pack or the like, and is used as a protective element that cuts off current when the battery or the internal temperature becomes abnormally high. For example, when a battery pack of a lithium ion battery is charged / discharged in an abnormal use state, the temperature becomes high. Therefore, when the temperature becomes higher than the set temperature, the current is interrupted by the breaker. Further, since the temperature of the motor or the like may become abnormally high in an overloaded state or an abnormal current flow, the temperature rise is limited by interrupting the current with the breaker even in this state.

The built-in circuit breaker used for the above applications is required to be small. A conventional breaker used for this type of application is shown in FIG. (See Patent Document 1)
In the breaker of this figure, a bimetal 108 is disposed between a fixed contact metal plate 104 and a movable contact metal plate 106. Further, in the breaker of this figure, a PTC heater 109 is disposed between the bimetal 108 and the fixed contact metal plate 104. The bimetal 108 is thermally deformed so as to be reversed when the set temperature is reached, and the movable contact 107 is separated from the fixed contact 105 to be turned off. This is because the inverted bimetal 108 pushes up the elastic arm 106 </ b> A of the movable contact metal plate 106 and separates the movable contact 107 from the fixed contact 105. The bimetal 108 that is not reversed, that is, the non-reversed state, is brought into an on state by bringing the movable contact 107 into contact with the fixed contact 105 without pushing up the elastic arm 106A of the movable contact metal plate 106.

FIG. 11A shows an on-state breaker in which the bimetal 108 is not inverted. In this breaker, the bimetal 108 in the non-inverted state does not push up the movable contact metal plate 106, and the movable contact 107 is brought into contact with the fixed contact 105 by the elasticity of the elastic arm 106A.
When the ambient temperature rises, the breaker switches to the off state by moving the movable contact 107 away from the fixed contact 105, as shown in FIG. It is done. This is because the reversed bimetal 108 pushes up the elastic arm 106 </ b> A of the movable contact metal plate 106.

  In the above breaker, it is important to reduce the contact resistance of the contacts to reduce the resistance in the on state. This is because on-resistance increases power loss and increases heat generation due to Joule heat. Heat generation due to Joule heat causes a malfunction such as heating the bimetal and switching to an off state when the ambient temperature does not reach the set temperature. In particular, since the heat generated by Joule heat increases in proportion to the square of the current, the amount of heat generated at the contact increases when used at a large current, and the switch is turned off when the ambient temperature is lower than the set temperature. The harmful effect is increased. This adverse effect can be prevented by reducing the contact resistance of the contact, that is, the ON resistance of the breaker.

Breakers have been developed that use silver contacts with low electrical resistance. (See Patent Document 2)
This breaker uses nickel silver alloy for the contacts to improve the durability of the silver contacts. Since silver contacts have low electrical resistance, adverse effects due to Joule heat are reduced, but the durability of the contacts is not guaranteed due to the low hardness of silver. In order to eliminate this drawback, the contact point is made of a silver alloy containing nickel to improve durability. This breaker uses a nickel-silver alloy for the movable contact and the fixed contact, thereby reducing the on-resistance while ensuring the durability of the contact. However, since this breaker is made of a nickel-silver alloy in order to ensure the durability of the contact, there is a drawback that the electrical resistance is increased by the contained nickel. The above circuit breaker uses nickel-containing alloy for silver contacts to improve contact durability, so the on-resistance of the contact increases due to the nickel contained to improve contact durability, Durability and on-resistance are mutually contradictory characteristics, and there is a drawback that it is extremely difficult to satisfy both on-resistance and durability.

JP 2002-56755 A JP 2002-56840 A

  The present invention has been developed for the purpose of solving the above-mentioned drawbacks. An important object of the present invention is to provide a DC breaker that achieves excellent durability while reducing the on-resistance of a contact.

Means for Solving the Problems and Effects of the Invention

  The DC breaker of the present invention has a fixed contact metal plate 4 provided with a fixed contact 5 on a base metal plate, and a movable contact 7 disposed at a position facing the fixed contact 5 of the fixed contact metal plate 4. The movable contact metal plate 6 is provided with the movable contact 7 provided on the elastic arm 6A of the base metal plate, and the bimetal 8 that pushes the elastic arm 6A to separate the movable contact 7 from the fixed contact 5. Further, the breaker uses a nickel-silver alloy contact 31 as one of the movable contact 7 and the fixed contact 5 and a silver contact 32 as the other contact. The silver contact 32 has a mixed layer 34 containing nickel in silver on the surface facing the nickel silver alloy contact 31. Furthermore, the nickel silver alloy contact 31 is fixed by plating, welding, or pressure contact on the surface of the base metal plate.

  The above breaker is characterized in that it can realize excellent durability while reducing the on-resistance of the contact. This is because the above breaker has one contact as a nickel silver alloy contact, the other as a silver contact, and the silver contact has a mixed layer containing nickel in silver on the surface thereof. Since the silver contact has a low electrical resistance, the on-resistance can be reduced. However, silver contacts cannot achieve excellent durability. In the above breaker, the opposing surface of the silver contact with the nickel-silver alloy contact is a mixed layer containing nickel in the silver, so that the mixed layer containing nickel in the silver of the silver contact and the nickel-silver alloy contact are opposed to each other. By arranging and contacting the silver-nickel mixed layer with the nickel-silver alloy, excellent durability is realized.

  The breaker for direct current of the present invention can be an inlay material in which the nickel silver alloy contact 31 is pressed against the surface of the base metal plate, and the nickel silver alloy contact 31 is made thicker than the silver contact 32. Can do. The above breaker realizes excellent durability even when it is switched on and off. The breaker that cuts off the direct current is likely to wear out one of the contacts, but the above breaker can be made thicker than the silver contact by using a nickel silver alloy contact as an inlay material. This breaker uses a nickel-silver alloy contact of an inlay material as a contact on the wear side, so that even if the contact of the nickel-silver alloy is worn, the on-resistance is kept small. This is because even if the nickel-silver alloy is worn, the surface of the silver contact is protected by a mixed layer containing nickel in silver. That is, in the above breaker, even if the nickel silver alloy contact is worn, the surface of this contact becomes a nickel silver alloy, and the surface of the silver contact becomes a mixed layer containing nickel in silver. It is held in a metal containing nickel in silver. For this reason, even if the contact is repeatedly switched on and off, excellent durability that maintains a small on-resistance and operates stably is realized.

In the DC breaker of the present invention, the mixed layer 34 containing nickel in silver is thinner than 1/10 of the total thickness of the silver contact 32, and the nickel-silver alloy contact 31 is thicker than the entire silver contact 32. can do.
This breaker achieves better durability by using a thick nickel silver alloy contact as a wear-side contact while reducing the on-resistance.

  In the DC breaker of the present invention, the mixed layer 34 containing nickel in silver is made thinner than 1/10 of the total thickness of the silver contact 32, and the silver contact 32 is silver-plated on the surface of the base metal plate. In addition, the silver plating layer 33 can be made into a structure having a mixed layer 34 containing nickel in silver on the surface of the silver plating layer 33.

  The above breaker is characterized in that the on-resistance can be further reduced. This is because the nickel-silver alloy is pressed against the base metal plate to form an inlay nickel-silver alloy contact, and the base metal plate is plated with silver to form a silver contact. An inlay made by press-contacting a nickel-silver alloy to a base metal plate is an ideal electrical connection state where the nickel-silver alloy and base metal plate are bonded together in a strong and low resistance state, and air does not enter the contact surface. In addition, silver plating is strongly bonded to the surface of the base metal plate in a low resistance state, and an ideal electrical connection state is obtained. For this reason, both the nickel silver alloy contacts and the silver contacts are connected to the base metal plate in an ideal state that minimizes the contact resistance. There is a feature that the resistance in the state can be maintained in a minimum state.

  In the DC breaker of the present invention, the movable contact 7 can be a nickel silver alloy contact 31, and the fixed contact 5 can be a silver contact 32 provided with a mixed layer 34 containing nickel in silver on the opposite surface. This breaker achieves excellent durability by using the movable contact as a contact on the wear side.

  In the breaker for direct current of the present invention, the fixed contact 5 can be a nickel silver alloy contact 31, and the movable contact 7 can be a silver contact 32 provided with a mixed layer 34 containing nickel in silver on the opposite surface. This breaker achieves excellent durability by using a fixed contact as a contact on the wear side.

In the DC breaker of the present invention, the nickel silver alloy contact 31 is thicker than the silver contact 32, the nickel silver alloy contact 31 is 10 μm or more and less than 50 μm, and the silver contact 32 is 2 μm or more. 20 μm or less.
Since the above breaker has a nickel silver alloy contact of 10 μm to 50 μm and a silver contact of 5 μm to 20 μm, particularly excellent durability is achieved by using the nickel silver alloy contact as a contact on the wear side.

  In the breaker for direct current of the present invention, the film thickness of the mixed layer 34 containing nickel in silver can be 1 μm or less. In this breaker, the mixed layer 34 containing nickel in silver is extremely thin as 1 μm or less, so that the contact layer has excellent durability due to the mixed layer containing nickel in silver while reducing the on-resistance in particular.

  The breaker for direct current of the present invention can be a silver contact 32 formed by depositing nickel on the surface of silver and providing a mixed layer 34 containing nickel in silver. This breaker is characterized in that a mixed layer containing nickel in silver can be easily provided on the opposite surface of the silver contact so that it can be mass-produced at low cost.

1 is a perspective view of a DC breaker according to an embodiment of the present invention. It is a vertical longitudinal cross-sectional view which shows the ON state of the breaker shown in FIG. It is a vertical longitudinal cross-sectional view which shows the OFF state of the breaker shown in FIG. It is the IV-IV sectional view taken on the line of the breaker shown in FIG. FIG. 3 is an exploded cross-sectional view of the breaker shown in FIG. 2. It is a top view of the main body case of the breaker shown in FIG. It is an expanded sectional view which shows the contact structure of the breaker shown in FIG. It is an expanded sectional view showing other examples of contact structure. It is an expanded sectional view showing other examples of contact structure. It is an expanded sectional view showing other examples of contact structure. It is sectional drawing which shows the conventional breaker.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment shown below exemplifies a DC breaker for embodying the technical idea of the present invention, and the present invention does not specify a DC breaker as follows. Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  A DC breaker 30 shown in FIGS. 1 to 6 includes an outer case 1, a fixed contact metal plate 4 having a fixed contact 5 disposed inside the outer case 1, and fixing of the fixed contact metal plate 4. A movable contact metal plate 6 having an elastic arm 6A for disposing the movable contact 7 at a position facing the contact 5 is provided. Further, the DC breaker 30 shown in the figure is a non-energized type breaker, and a bimetal 8 which is deformed at an ambient temperature to switch the movable contact metal plate 6 from on to off, the movable contact metal plate 6 and the outer case bottom 1T. Between them. Furthermore, the breaker 30 in the figure also includes a PTC heater 9 that heats the bimetal 8. The breaker 30 shown in the figure includes the PTC heater 9, but the breaker of the present invention does not necessarily include the PTC heater.

  The elastic arm 6 </ b> A of the movable contact metal plate 6 has elasticity to bring the movable contact 7 into contact with the fixed contact 5 by its own elasticity when not pressed by the bimetal 8. The bimetal 8 is disposed between the elastic arm 6 </ b> A and the PTC heater 9. The bimetal 8 is in a non-deformed state in which it is not thermally deformed in a state lower than the set temperature. In this state, the bimetal 8 does not push the elastic arm 6A, and the breaker 30 is brought into an on state by bringing the movable contact 7 into contact with the fixed contact 5 by the elasticity of the elastic arm 6A. When the breaker 30 becomes higher than the set temperature, the bimetal 8 is thermally deformed and inverted to be in an inverted curved state. The bimetal 8 in the inverted curved state is brought into contact with the PTC heater 9 on the outer case bottom 1T, pushes the elastic arm 6A at the outer peripheral edges at both ends, and moves the movable contact 7 away from the fixed contact 5 to switch to the off state. .

  The bimetal 8 is formed by laminating metals having different coefficients of thermal expansion so that the temperature rises and is thermally deformed. The bimetal 8 has a quadrangular outer shape and is curved in a central convex shape. The bimetal 8 is located between the elastic arm 6A and the outer case bottom 1T, and in the figure, is located between the elastic arm 6A and the PTC heater 9, and when it reaches a set temperature, it is thermally deformed and inverted to be in an inverted curved state.

  The bimetal 8 can be deformed from the non-deformed state to the inverted curved state and is disposed in the bimetal storage portion 28 provided in the outer case 1 so as not to be displaced. As shown in the plan view of FIG. 6, the exterior case 1 is provided with a bimetal storage portion 28 for arranging the square bimetal 8 at a fixed position. The outer case 1 is provided with an outer peripheral wall 10 around the bimetal 8, and the inner side of the outer peripheral wall 10 serves as a bimetal storage portion 28. The bimetal storage portion 28 surrounded by the outer peripheral wall 10 has an inner shape slightly larger than the outer shape of the bimetal 8 and is disposed at a fixed position in a state where the bimetal 8 can be deformed into an undeformed state and an inverted curved state. .

  The movable contact metal plate 6 is a metal plate that is elastically deformed, and includes a fixed portion 6B that is fixed to the exterior case 1 and an elastic arm 6A that is provided with a movable contact 7 at the tip. As shown in FIGS. 2 and 3, the movable contact metal plate 6 fixes the fixed portion 6 </ b> B to the exterior case 1, and the elastic arm 6 </ b> A on the distal end side is disposed in the storage space 20 provided in the exterior case 1. doing. The movable contact metal plate 6 has a fixed portion 6B fixed to the upper part of the second outer wall 11B provided in the exterior case 1. The movable contact metal plate 6 projects the outer side of the fixed portion 6B from the exterior case 1, and this projecting piece 6X serves as a movable-side connection terminal 41.

  The movable contact metal plate 6 is an elastic arm 6A disposed in the storage space 20 or a metal plate that can be elastically deformed as a whole. Further, the movable contact metal plate 6 is provided with a movable contact 7 on a surface facing the fixed contact 5 at the tip of the elastic arm 6A. When the bimetal 8 is not deformed, the movable contact metal plate 6 brings the movable contact 7 into contact with the fixed contact 5 to turn on the breaker, and when the bimetal 8 is in an inverted curved state, the movable contact metal plate 6 has an elastic arm 6A pushed by the bimetal 8. Due to elastic deformation, the movable contact 7 is separated from the fixed contact 5 and the breaker is turned off.

  The movable contact metal plate 6 is made of phosphor bronze having a thickness of 100 μm as a base metal plate, and the movable contact is pressed and fixed to the base metal plate. However, as the base metal plate of the movable contact metal plate, an elastic metal plate other than conductive phosphor bronze having a thickness of 200 μm or less can be used. If the movable contact metal plate 6 is too thick, the force that the bimetal deforms increases, and conversely if it is too thin, the current capacity decreases. Therefore, an elastic metal plate with a thickness of 200 μm or less is used as the base metal plate so that it can be quickly elastically deformed with a thin bimetal, and since the current capacity is increased, an elastic with a thickness of 50 μm or more is used. A metal plate is used.

  The movable contact metal plate 6 shown in the enlarged cross-sectional view of FIG. 7 is provided with a silver plating layer 33 at the tip of the elastic arm 6A, the portion provided with the silver plating layer 33 is bent and folded, and the folded piece 6E. Are arranged on the fixed contact 5 side, and a protruding portion 6D protruding to the fixed contact 5 side is provided as the movable contact 7 of the silver contact 32. The movable contact metal plate 6 shown in the enlarged sectional view of FIG. 8 is provided with a silver plating layer 33 at the tip of the elastic arm 6A and press-worked to provide a protrusion 6D. The protrusion 6D is used as a movable contact of the silver contact 32. 7 and so on. The movable contact metal plate 6 is provided with a protruding portion 6D having a silver plated layer 33 on the surface by silver plating on the tip of the elastic arm 6A, then bending or pressing, and the movable contact of the silver contact 32 7, or after bending or pressing, the silver plating layer 33 may be provided on the surface of the protrusion 6 </ b> D to form the movable contact 7 of the silver contact 32.

  The thickness of the silver contact 32 is 5 μm. However, the thickness of the silver contact can be 2 μm to 50 μm, preferably 3 μm to 20 μm. Although the silver contact 32 has a small electrical resistance, it cannot realize a sufficient durability. Therefore, a mixed layer 34 containing nickel in silver is provided on the surface facing the fixed contact 5. Since the mixed layer 34 containing nickel in silver can be thinned to reduce the on-resistance, it is thinner than 1/10 of the total thickness of the silver contact 32, preferably 1 μm or less, more preferably 0.1 μm or less. The mixed layer 34 containing nickel in silver is provided on the surface of the silver contact 32 by depositing nickel on the surface of the silver contact 32 or by depositing nickel and silver. In order to deposit only nickel and provide a mixed layer containing nickel in silver, the thickness of the deposited nickel is reduced to 50 nm or less. The mixed layer can also be provided by plating on the surface of the silver contact. However, this invention does not specify the manufacturing method of the silver contact which has a mixed layer on the surface to vapor deposition or plating.

  Furthermore, the movable contact metal plate 6 shown in FIGS. 2 to 5 is provided with a convex portion 6C on the bimetal 8 side. The movable contact metal plate 6 shown in the figure is provided with a pair of convex portions 6C that come into contact with the bimetal 8 so as to protrude toward the bimetal 8 side. As shown in FIG. 6, the pair of convex portions 6 </ b> C are arranged on the center line m extending in the longitudinal direction of the movable contact metal plate 6 and separated in the longitudinal direction of the movable contact metal plate 6. The movable contact metal plate 6 is configured such that the outer peripheral edge portions at both ends of the bimetal 8 are brought into contact with the pair of convex portions 6C and pressed against each other. The convex portion 6C shown in the figure has an arc shape, and the outer peripheral edge portion 8b of the bimetal 8 is brought into contact with each other without sliding in the lateral direction so that they can be pressed against each other. Although not shown, the movable contact metal plate may be provided with a plurality of convex portions on the lower surface facing both ends of the bimetal.

  The fixed contact metal plate 4 is fixed to the main body case 2 by insert molding. The fixed contact metal plate 4 is insert-molded so that the front end portion 4A is embedded in the bottom portion 13 of the storage space 20, and the intermediate portion 4B is embedded from the bottom portion 13 of the storage space 20 into the first outer wall 11A of the main body case 2. The main body case 2 is fixed. The fixed contact metal plate 4 shown in FIGS. 2 and 3 is provided with a step 4D so that a portion embedded in the first outer wall 11A is higher than a portion closing the bottom of the heater housing 29. 4D is embedded in the bottom part 13 of the main body case 2, and the rear end side of the step part 4 </ b> D is exposed on the upper surface of the bottom part 13, and this exposed part is used as the fixed contact 5.

  As shown in FIGS. 7 and 8, the fixed contact metal plate 4 is formed by pressing a nickel silver alloy on a part of the surface of the base metal plate, that is, as an inlay material between the base metal plate and the nickel silver alloy. The fixed contact 5 is made of nickel silver alloy. The nickel silver alloy contact 31 which is the fixed contact 5 can increase the contact life by increasing the thickness of the nickel silver alloy to be pressed. Since the nickel-silver alloy contact 31 is used as a contact on the wear side, the film thickness thereof is thicker than that of the mixed layer 34, more preferably thicker than the entire silver contact 32. Therefore, the thickness of the nickel silver alloy contact 31 is preferably 10 μm or more, more preferably 15 μm or more. If the nickel silver alloy contact 31 is made thick, the manufacturing cost becomes high. Therefore, it is preferably thinner than 50 μm, more preferably thinner than 30 μm.

  The above breaker uses a nickel silver alloy contact as an inlay material, and the nickel silver alloy contact can be provided by welding a nickel silver alloy thicker than the silver contact on the surface of the base metal plate. Further, a nickel-silver alloy can be plated on the surface of the base metal plate.

  The DC breaker described above has, for example, a nickel silver alloy contact 31 having a thickness of 5 μm for the entire silver contact with the mixed layer 34 and a thickness of 30 μm for the nickel silver alloy contact 31 in pressure contact with the base metal plate. Is used as a contact on the wear side, and in a resistive load with a voltage of 9 V and a current of 15 A, an extremely excellent characteristic that can increase the on-resistance after switching to 6000 times on / off to 1 mΩ or less is realized.

  In the above DC breaker, the movable contact 7 is a silver contact 32 and the fixed contact 5 is a nickel silver alloy inlay material thicker than the silver contact 32. However, the DC breaker of the present invention is shown in FIGS. As shown in FIG. 3, the fixed contact 5 is a silver contact 32, the movable contact 7 is a nickel silver alloy contact 31 thicker than the silver contact 32, and the silver contact 32 is provided with a mixed layer 34 on the surface facing the movable contact 7. The nickel silver alloy contact 31 of the movable contact 7 can also be used as a contact on the wear side.

  In the breaker 30 shown in FIGS. 1 to 6, the outer case 1 is formed of a plastic main body case 2 and a lid case 3 having a plastic portion. 1 to 6, the fixed contact metal plate 4 is insert-molded and fixed to the bottom 13 of the main body case 2 and the lid case 3 is fixed to the upper surface. The main body case 2 is provided at both end portions so as to project the first outer wall 11A and the second outer wall 11B, and a storage space 20 is provided between the first outer wall 11A and the second outer wall 11B. Yes. The storage space 20 is closed at the bottom by the fixed contact metal plate 4 and closed at the top by the lid case 3. Therefore, the fixed contact metal plate 4 is exposed on the bottom surface of the exterior case 1.

  The movable contact metal plate 6, the fixed contact metal plate 4, and the lid case 3 are fixed to the main body case 2. The main body case 2 is provided with a first outer wall 11A and a second outer wall 11B on both sides of a storage space 20 for storing the bimetal 8 and the PTC heater 9, and further between the first outer wall 11A and the second outer wall 11B. The opposing wall 12 which connects between is provided, and the outer peripheral wall 10 which surrounds the circumference | surroundings of the storage space 20 with the pair of opposing walls 12 and the pair of outer walls 11 is constituted. Therefore, the storage space 20 has a hollow shape in which the periphery is surrounded by the outer peripheral wall 10, the bottom is closed with the fixed contact metal plate 4, and the top is closed with the lid case 3.

  The main body case 2 is formed by insert-molding a part of the fixed contact metal plate 4 on the first outer wall 11A, and an intermediate portion 4B of the fixed contact metal plate 4 in the middle of the first outer wall 11A in FIGS. It is fixed. Accordingly, the fixed contact metal plate 4 is fixed to the main body case 2 while penetrating the first outer wall 11A, and the portion exposed to the inside of the storage space 20 is used as the fixed contact 5, and the protruding piece 4X drawn out is fixed. This is the connection terminal 42 on the side.

  Further, in the main body case 2, the fixed portion 6 </ b> B of the movable contact metal plate 6 is fixed to the second outer wall 11 </ b> B, and the elastic arm 6 </ b> A of the movable contact metal plate 6 is disposed in the storage space 20. 2 and 3 has a fixed portion 6B of the movable contact metal plate 6 fixed to the upper end surface of the second outer wall 11B. As shown in FIGS. 2, 3, and 6, the main body case 2 is provided with a step recess 21 that is one step lower than the upper surface of the outer peripheral wall 10 on the upper surface of the second outer wall 11 </ b> B. The fixed portion 6B of the movable contact metal plate 6 is fitted and arranged at a fixed position. The main body case 2 shown in the figure is provided with a connecting convex portion 15 that protrudes from the central portion of the fitting concave portion 21 and penetrates the fixed portion 6B of the movable contact metal plate 6. The fixed portion 6B of the movable contact metal plate 6 is provided with a through hole 6F through which the connecting convex portion 15 passes. The connecting convex portion 15 shown in FIG. 6 has an oval horizontal cross-sectional shape so that the fixed portion 6B of the movable contact metal plate 6 can be disposed in the step concave portion 21 with an accurate posture. Further, the step recess 21 shown in FIG. 6 is formed with positioning ribs 22 for positioning both sides of the movable contact metal plate 6 at the upper end of the second outer wall 11B. The second outer wall 11 </ b> B shown in FIG. 6 has a step-shaped positioning rib by providing a fitting recess 21 at the upper end surface with a portion other than the positioning rib 22 being lower than the upper surface of the outer peripheral wall 10. 22 is formed. The movable contact metal plate 6 is provided with positioning recesses 6G for guiding the positioning ribs 22 on both sides of the fixed portion 6B. In the movable contact metal plate 6, the connecting convex portion 15 is inserted into the through hole 6F opened in the fixed portion 6B, and the positioning ribs 22 are guided to the positioning concave portions 6G provided on both sides of the fixed portion 6B. It arrange | positions in the fixed position of the level | step difference recessed part 21 of the 2nd outer wall 11B. The movable contact metal plate 6 in which the fixed portion 6B is disposed in the stepped recess 21 is bonded and fixed to the second outer wall 11B, or sandwiched between the lid case 3 fixed to the main body case 2, that is, the second The outer wall 11 </ b> B is sandwiched between the bottom surface of the stepped recess 21 and the facing surface of the lid case 3 from the upper and lower surfaces and fixed to a fixed position of the outer case 1.

  As shown in FIGS. 1 to 6, the lid case 3 fixes the laminated metal plate 25 on the outer side of the movable contact metal plate 6 on the upper end opening side of the main body case 2 and the laminated metal plate 25. Connecting plastic 26. The lid case 3 has a laminated metal plate 25 exposed on the inner surface side, that is, the main body case 2 side, and the upper side of the movable contact metal plate 6 is covered with the laminated metal plate 25. It is arranged on the part side. The lid case 3 shown in FIGS. 1 to 6 is insulated by covering almost the entire surface of the laminated metal plate 25 with a connecting plastic 26 on the upper surface side. The laminated metal plate 25 is fixed to the connecting plastic 26 by insert molding. The laminated metal plate 25 to be insert-molded is temporarily fixed in a molding chamber of a mold for molding the connecting plastic 26, and molten plastic is injected into the molding chamber and fixed to the connecting plastic 26.

  The lid case 3 is fixed to the main body case 2 by fixing the outer peripheral edge portion of the connecting plastic 26 to the upper surface of the outer peripheral wall 10 of the main body case 2. As shown in FIG. 5, the connecting plastic 26 of the lid case 3 includes an outer peripheral wall 27 protruding toward the main body case 2 on the outer peripheral edge facing the outer peripheral wall 10 of the main body case 2. The laminated metal plate 25 is exposed inside. The outer peripheral wall 27 of the connecting plastic 26 is fixed to the first outer wall 11 </ b> A and the second outer wall 11 </ b> B provided at both ends of the main body case 2, and is further fixed to the opposing wall 12.

  The exterior case 1 shown in FIG. 5 includes connection convex portions 15 and 17 and connection concave portions 16 and 18 that are fitted to each other in order to connect the lid case 3 and the main body case 2 with accurate positioning. As described above, the main body case 2 is provided with the projecting convex portion 15 protruding from the fixed portion 6B of the movable contact metal plate 6 on the upper surface of the second outer wall 11B. The lid case 3 is provided with a connecting concave portion 16 for guiding the connecting convex portion 15 at a position facing the connecting convex portion 15 at the end of the main body case 2 on the second outer wall 11B side. Furthermore, the lid case 3 shown in FIG. 5 is provided with connecting projections 17 projecting from the lower surface of the outer peripheral wall 27 toward the main body case 2 on both sides of the end portion of the main body case 2 on the first outer wall 11A side. . As shown in FIG. 6, the main body case 2 is provided with a connection recess 18 for guiding the connection protrusion 17 on the upper surface of the facing wall 12 facing the connection protrusion 17. In the outer case 1 described above, the connecting projections 17 on both sides of the lid case 3 are guided to the connecting recesses 18 of the main body case 2 at the end of the main body case 2 on the first outer wall 11A side. At the end portion on the second outer wall 11B side, the connecting convex portion 15 penetrating the fixed portion 6B of the movable contact metal plate 6 is guided by the connecting concave portion 16 of the lid case 3, so that the lid case 3 is accurately connected to the main body case 2. Linked to position.

  The lid case 3 and the main body case 2 that are connected to the fixed positions via the connecting convex portions 15 and 17 and the connecting concave portions 16 and 18 are ultrasonically welded to fix the connecting plastic 26 to the main body case 2. The lid case 3 shown in FIG. 5 is located on the lower surface of the outer peripheral wall 27 of the connecting plastic 26 and is opposed to the outer peripheral wall 10 of the main body case 2, and has a molten ridge 19 that is melted by ultrasonic vibration. Provided. The lid case 3 shown in the figure is provided with a molten protrusion 19 protruding along the lower surface of the outer peripheral wall 27. The lid case 3 is provided with a melting ridge 19 having a substantially U-shape in a bottom view at an outer peripheral edge portion excluding a portion facing the fixed portion 6 </ b> B of the movable contact metal plate 6. The lid case 3 is ultrasonically vibrated at the outer peripheral portion in a state where it is connected to a fixed position of the main body case 2 via the connecting convex portions 15 and 17 and the connecting concave portions 16 and 18, and the molten convex strip 19 is It is melted by frictional heat and welded to the outer peripheral wall 10 of the main body case 2. Further, the lid case 3 and the main body case 3 that are ultrasonically vibrated are fused to each other by the frictional heat between the contact portions of the connecting projections 15 and 17 and the connecting recesses 16 and 18 that are connected to each other. However, the exterior case can be fixed by bonding the connecting plastic of the lid case and the main body case, or by connecting with a fitting structure or a locking structure.

  The breaker 30 shown in FIGS. 1 and 2 is a pressing convex portion that presses the rear end portion of the elastic arm 6A downward so that the movable contact 7 can surely come into contact with the fixed contact 5 in a state where the bimetal 8 is not thermally deformed. 25A is provided so as to protrude from the inner surface of the laminated metal plate 25. The movable contact metal plate 6 is configured such that when the rear end portion of the elastic arm 6A is pressed downward by the pressing convex portion 25A, the distal end portion of the elastic arm 6A is urged downward, and the movable contact 7 at the distal end is reliably secured. To the fixed contact 5.

  Further, the outer case 1 shown in FIGS. 2 to 5 is provided with a heater storage portion 29 in which the PTC heater 9 is disposed at the bottom of the storage space 20 of the main body case 2. The heater storage portion 29 is provided inside the bimetal storage portion 28 and provided at the bottom thereof. The heater accommodating portion 29 is a recess that fixes the PTC heater 9 so as not to come out to a fixed position. The PTC heater 9 is fixed to the heater housing 29 by being bonded thereto, or is fitted and fixed so as not to come off. The heater storage portion 29 is in the central portion of the storage space 20, and the bottom surface thereof is closed by the front end portion 4 </ b> A of the fixed contact metal plate 4. The heater housing 29 has an inner shape slightly larger than the outer shape of the PTC heater 9 so that the PTC heater 9 can be inserted therein. Moreover, the heater accommodating part 29 is providing the convex part 14 along the outer periphery. The PTC heater 9 inserted into the heater housing 29 has a bimetal 8 that protrudes slightly from the upper surface of the convex portion 14 and is curved on the upper surface.

  In the storage space 20, the bottom surface of the heater storage portion 29 is closed with the fixed contact metal plate 4, and the outer bottom surface of the heater storage portion 29 is closed with the plastic of the main body case 2. The main body case 2 is fixed to the main body case 2 by insert-molding the fixed contact metal plate 4 on the plastic bottom portion 13 that closes the bottom of the storage space 20 outside the heater storage portion 29.

  The breaker 30 shown in FIGS. 1 to 6 accommodates the PTC heater 9, the bimetal 8, and the elastic arm 6 </ b> A of the movable contact metal plate 6 in the storage space 20 of the main body case 2 in order from the bottom. The intermediate portion 4B of the fixed contact metal plate 4 is fixed to the first outer wall 11A, and the fixed portion 6B of the movable contact metal plate 6 is fixed to the second outer wall 11B.

  The PTC heater 9 generates heat when energized and heats the bimetal 8. The PTC heater 9 is a PTC heater having a thickness in which the opposing surface is circular or oval, and electrodes are provided on the upper surface and the lower surface. The PTC heater 9 provided with electrodes on the upper and lower surfaces makes the lower surface contact the fixed contact metal plate 4 and allows the upper surface to contact the movable contact metal plate 6 via the bimetal 8. When the movable contact 7 of the movable contact metal plate 6 contacts the fixed contact 5, the PTC heater 9 is not in contact with the movable contact metal plate 6 and the bimetal 8 and is not energized. In a state where the movable contact 7 of FIG. 6 is separated from the fixed contact 5 and is turned off, the bimetal 8 is energized through the bimetal 8 that contacts the movable contact metal plate 6 and the fixed contact metal plate 4 to generate heat, thereby heating the bimetal 8. . As shown in FIG. 3, the heated bimetal 8 holds the movable contact 7 in an off state away from the fixed contact 5.

  Since the breaker 30 holds the movable contact 7 in the off state in a state where the breaker 30 is switched to the off state, the breaker 30 can be used for a battery pack to improve safety. That is, after the battery pack becomes abnormal temperature and the breaker 30 is switched off, the PTC heater 9 is continuously energized from the battery pack battery and the bimetal 8 is heated, so the breaker 30 returns to the on state. It is because it can hold | maintain in the state which interrupts | blocks an electric current until a battery is discharged, without doing. When the battery is completely discharged, the PTC heater cannot be energized and the PTC heater cannot heat the bimetal, and the breaker returns to the ON state. However, in this state, the battery cannot be discharged. Is secured. In addition, when the battery pack is connected to the charger and becomes charged, the battery pack becomes abnormal temperature and the current is cut off by the breaker. Since it can be maintained in the state, it can be maintained in a state where the current is interrupted while power is supplied from the charger without the breaker returning to the on state. Therefore, after the breaker is switched off, the battery pack can maintain the breaker in the off state by energizing the PTC heater until the energized state is released, thereby further improving safety.

  After the breaker 30 is assembled, the on-resistance can be further stabilized by activating the contact by ultrasonic vibration while energizing the contact. The breaker causes the movable contact 7 and the fixed contact 5 to collide with each other and ultrasonically vibrate in the separation direction. That is, the breaker ultrasonically vibrates so that the fixed contact and the movable contact approach each other and collide with each other and move relatively away from each other. The contact current in the state of ultrasonic vibration is preferably 0.1 A to 100 A in a resistive load state. By increasing the contact current during ultrasonic vibration, the contact is activated more effectively. A load having an inductance connecting a coil in series with a resistor increases the current energy stored in the coil when the current is cut off, so that the contact current can be reduced to activate the contact. This is because the discharge current of the contact increases in order to consume the energy of the current stored in the coil. Therefore, the contact current is set to an optimum value in consideration of the resistance load and the inductance load. Further, the breaker has a characteristic that when the current at the contact is increased, the circuit breaker generates heat due to Joule heat and can be switched off by itself. In order to activate the contact by ultrasonic vibration, it is necessary to keep the movable contact 7 in an ON state in contact with the fixed contact 5. Accordingly, in the method of causing ultrasonic vibration by flowing a large current through the contact, the ultrasonic vibration is performed in a state where the contact is in an ON state by shortening the time for ultrasonic vibration. Therefore, the method of causing ultrasonic vibration by flowing a large current through the contact shortens the time for ultrasonic vibration.

  The time for ultrasonically vibrating the contact in the energized state is 0.1 milliseconds to 1 second. The time for ultrasonic vibration can be increased to activate the contact more effectively. However, if the time is too long, the silver plating layer 33 of the contact is damaged. Therefore, the contact can be activated without damaging the silver plating layer 33. Set to time. In addition, contact activation by ultrasonic vibration is also affected by contact current, load type, and amplitude of ultrasonic vibration. When the contact current and amplitude are large, the contact is more effectively activated in a short time. . Therefore, the ultrasonic vibration time is set to an optimum value within the above-mentioned range in consideration of the contact current and the amplitude of the ultrasonic vibration.

  The frequency for ultrasonically vibrating the contacts is 20 KHz to 6 GHz, preferably 20 KHz to 1 GHz. By increasing the frequency of ultrasonic vibration, the number of collisions and separation between the movable contact 7 and the fixed contact 5 can be increased per unit time. However, if the frequency of the ultrasonic vibration is too high, the interval at which the movable contact 7 is separated from the fixed contact 5 is narrowed and activation due to discharge is reduced. Conversely, if the frequency is too low, the number of collisions is reduced and activation is reduced. Therefore, the frequency of the ultrasonic vibration is set to an optimum value in consideration of the thickness and length of the elastic arm 6A and further in consideration of the resonance frequency of the elastic arm 6A.

  Furthermore, the amplitude for ultrasonically vibrating the breaker is set to 0.01 μm to 100 μm. By increasing the amplitude of the ultrasonic vibration, the energy of the movement of the movable contact 7 colliding with the fixed contact 5 can be increased, and the interval at which the movable contact 7 is separated from the fixed contact 5 can be increased. The amplitude for ultrasonically vibrating the breaker affects the distance at which the movable contact 7 is separated from the fixed contact 5. However, the interval at which the movable contact 7 is separated from the fixed contact 5 can be made larger than the amplitude for ultrasonically vibrating the breaker by resonating the elastic arm 6A. Accordingly, the movable contact 7 is fixed to the fixed contact by setting the frequency for ultrasonically vibrating the breaker to the resonance frequency of the elastic arm 6A, the vicinity thereof, an integral multiple of the resonance frequency, or an integral fraction of the resonance frequency. It can be effectively activated at a sufficient distance from 5.

  In order to increase the amplitude for ultrasonically vibrating the breaker, it is necessary to increase the output of an ultrasonic transducer or ultrasonic horn that contacts the breaker and ultrasonically vibrates the breaker. When a high-power ultrasonic vibrator or ultrasonic horn is pressed against the outer case 1 of the breaker and ultrasonically vibrated, there is a detrimental effect such as deformation of the contact point with the ultrasonic vibrator due to heat generated by the ultrasonic vibration. The amplitude for ultrasonically oscillating the breaker is set to be small as long as the contact can be activated.

  The above breaker can be used, for example, as a protection element that is used in a battery pack and connected in series with the battery of the battery pack. The breaker, which is a protective element, detects the battery temperature and ambient temperature, and when the detected temperature exceeds the set temperature, the bimetal is thermally deformed to cut off the current.

DESCRIPTION OF SYMBOLS 1 ... Exterior case 1T ... Exterior case bottom part 2 ... Main body case 3 ... Cover case 4 ... Fixed contact metal plate 4A ... Tip part
4B ... Intermediate part
4D ... Step part
4X ... projecting piece 5 ... fixed contact 6 ... movable contact metal plate 6A ... elastic arm
6B ... Fixed part
6C ... convex part
6D ... Projection
6E ... folded piece
6F ... Through hole
6G Positioning recess
6X ... projecting piece 7 ... movable contact 8 ... bimetal 9 ... PTC heater 10 ... outer peripheral wall 11 ... outer wall 11A ... first outer wall
DESCRIPTION OF SYMBOLS 11B ... 2nd outer wall 12 ... Opposite wall 13 ... Bottom part 14 ... Convex part 15 ... Connection convex part 16 ... Connection concave part 17 ... Connection convex part 18 ... Connection concave part 19 ... Melting convex line 20 ... Storage space 21 ... Step concave part 22 ... Positioning rib 25 ... Laminated metal plate 25A ... Pressing convex portion 26 ... Connecting plastic 27 ... Outer peripheral wall 28 ... Bimetal housing portion 29 ... Heater housing portion 30 ... Breaker 31 ... Nickel silver alloy contact 32 ... Silver contact 33 ... Silver plated layer 34 ... Mixed layer 41 ... Moving side connection terminal 42 ... Fixed side connection terminal 104 ... Fixed contact metal plate 105 ... Fixed contact 106 ... Moving contact metal plate 106A ... Elastic arm 107 ... Moving contact 108 ... Bimetal 109 ... PTC heater m ... Center line

Claims (10)

A fixed contact metal plate (4) having a base metal plate provided with a fixed contact (5) and a movable contact (7) disposed at a position facing the fixed contact (5) of the fixed contact metal plate (4). The movable contact metal plate (6) provided with the movable contact (7) on an elastic arm (6A) of a base metal plate, and the movable contact (7) is fixed by pressing the elastic arm (6A). A breaker comprising a bimetal (8) separated from the contact (5),
The movable contact (7) and the fixed contact (5), one contact as a nickel silver alloy contact (31), the other contact as a silver contact (32),
The silver contact (32) has a mixed layer (34) containing nickel in silver on the surface facing the nickel silver alloy contact (31),
Furthermore, the nickel-silver alloy contact (31) is formed by plating, welding or press-contacting the surface of the base metal plate.   2. The DC breaker according to claim 1, wherein the nickel-silver alloy contact (31) is an inlay material pressed against the surface of the base metal plate. 3.   3. The DC breaker according to claim 1, wherein the nickel silver alloy contact (31) is thicker than the silver contact (32). The mixed layer (34) containing nickel in the silver is thinner than 1/10 of the total thickness of the silver contact (32),
4. The DC breaker according to claim 1, wherein the nickel silver alloy contact (31) is thicker than the entire silver contact (32). The mixed layer (34) containing nickel in the silver is thinner than 1/10 of the total thickness of the silver contact (32),
The silver contact (32) is a silver plating layer (33) formed by silver plating on the surface of a base metal plate, and a mixed layer (34) containing nickel in the silver is formed on the surface of the silver plating layer (33). The DC breaker according to any one of claims 1 to 4, which is provided.   The movable contact (7) is a nickel silver alloy contact (31), and the fixed contact (5) is a silver contact (32) in which a mixed layer (34) containing nickel in silver is provided on the opposing surface. DC breaker described in any one of 5 thru | or 5.   The fixed contact (5) is a nickel silver alloy contact (31), and the movable contact (7) is a silver contact (32) in which a mixed layer (34) containing nickel in silver is provided on the opposing surface. DC breaker described in any one of 5 thru | or 5. The nickel silver alloy contact (31) is thicker than the silver contact (32),
The nickel silver alloy contact (31) is 10 μm or more and thinner than 50 μm,
The DC breaker according to any one of claims 1 to 7, wherein the silver contact (32) is 2 µm or more and 20 µm or less.   The DC breaker according to any one of claims 1 to 8, wherein the mixed layer (34) containing nickel in silver has a thickness of 1 µm or less.   The DC breaker according to any one of claims 1 to 9, wherein the silver contact (32) is provided with a mixed layer (34) containing nickel on silver by vapor-depositing nickel on the surface of silver.

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