JP4841271B2 - Joint structure of heater and bimetal - Google Patents

Description

  The present invention relates to a junction structure of a heater and a bimetal used for an overcurrent tripping portion of a circuit breaker for wiring or an earth leakage breaker.

  A bimetal obtained by bonding two pieces of metal having different thermal expansion coefficients is used for an overcurrent tripping portion of a circuit breaker or a circuit breaker. When the rated current is low, a direct-heating overcurrent tripping part that bends the bimetal by flowing current directly through the bimetal is used, but when the rated current is high, the electrical resistance of the bimetal is high. If current is passed directly through the bimetal, it may burn out due to overcurrent. For this reason, in a circuit breaker with a high rated current, a side-heated overcurrent tripping section is used in which a heater that generates heat by energization is joined adjacent to the bimetal and the bimetal is bent.

  FIG. 5 shows an example of a conventional joining structure of a heater and a bimetal. A hole 53 is formed at the end of the bimetal 51 and the heater 52, and a rivet 54 is inserted into the hole 53 and crimped. However, this joining structure requires a rivet 54, which increases the cost.

  In addition, as shown in FIG. 6, there is a joining structure in which the rear side of the heater 55 is knocked out to form a jock 56, and the jock 56 is inserted into the hole 53 of the bimetal 51 and then caulked. However, depending on the material of the heater 55, it may be difficult to form the jock 56, and since there are several types of plate thickness of the bimetal 51, the jock 56 having an appropriate height corresponding to the plate thickness is formed. There is a problem that is not easy. Further, there is a limit to the height of the jock 56 that can be knocked out, and depending on the thickness of the bimetal 51, it may be difficult to join by this method.

As another method, there is a method in which a heater and a bimetal are welded and joined as shown in Patent Document 1, but there is a possibility that the characteristics of the bimetal may change due to the heat of welding.
JP-A-8-17324

  The present invention has been completed for the purpose of solving the above-described problems and providing a heater-bimetal junction structure that can be joined with stable quality without increasing costs. is there.

The present invention, which has been made to solve the above-mentioned problems, is a bonding structure of a plate-like heater that generates heat due to overcurrent and a bimetal that is arranged adjacent to the heater and curves by the heat generated by the heater. A heater and bimetal are joined by forming a cut-and-raised part on one side, forming a hole corresponding to the cut-and-raised part on the other, and inserting and caulking the cut-and-raised part into the hole. In addition, the lower portion of the heater is fixed to the fixed contact mounting member, and the bent portion of the end portion of the fixed contact mounting member is extended above the portion where the width is narrowed by the cut or raised portion of the heater or bimetal. it is characterized in that the. It is preferable that the cut-and-raised portions are formed on both sides of the heater or bimetal in the width direction.

In the heater / bimetal bonding structure according to the present invention, a cut-and-raised portion is formed in one of the heater and the bimetal, a hole corresponding to the cut-and-raised portion is formed in the other, and the cut-and-raised portion is formed in the hole. Therefore, it is possible to join the heater and the bimetal reliably while suppressing the cost without requiring other parts for joining. In addition, since welding is not used, the quality does not become unstable due to welding heat. Furthermore, since the length of the cut-and-raised part can be set relatively freely unlike the jockey, bimetals having different plate thicknesses can be reliably joined to the heater. In particular, if the cut-and-raised portions are formed on both sides of the heater or bimetal in the width direction, the cut-and-raise is easy, and the heater and the bimetal can be reliably bonded. Further, since the bent portion at the end of the fixed contact mounting member is extended above the portion where the width is narrowed by forming the cut-and-raised portion, the current to the heater is affected by the narrowed portion. There is nothing.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
In FIGS. 1 and 2, 1 is a bimetal, and 2 is a plate-like heater arranged adjacent to the bimetal 1. The heater 2 is fixed to the fixed contact mounting member 18 of the circuit breaker by welding. A raised portion 3 is formed at a position slightly above the lower end of the heater 2 from both sides in the width direction. On the other hand, the bimetal 1 is formed with a substantially rectangular hole 4 corresponding to the cut and raised portions 3, and the cut and raised portion 3 of the heater 2 is inserted into the hole 4 of the bimetal 1 as shown in FIG. The bimetal 1 and the heater 2 are joined by caulking the cut-and-raised portion 3.

  In this embodiment, the cut-and-raised portion 3 is formed on the heater 2 side. However, the cut-and-raised portion 3 is formed on the bimetal 1 side, and the hole 4 corresponding to the cut-and-raised portion 3 is formed on the heater 2 side. There is no problem.

  Further, as shown in FIG. 3, the cut-and-raised portion 3 may have a structure protruding from the width of the heater 2. With such a structure, the length of the cut-and-raised portion 3 can be arbitrarily set, so that the case where the heater 2 is narrow or the bimetal 1 is thick can be handled. it can.

  In addition, although the heater 2 forms the cut-and-raised portion 3, a portion having a narrow width is generated, but the bent portion 22 of the fixed contact mounting member 18 extends upward from the narrow portion. The current to the heater 2 is not affected by the narrowed portion.

  As described above, according to the present invention, since no other parts such as rivets are required for joining, the heater 2 and the bimetal 1 can be joined with stable quality without increasing the cost. It becomes. Also, the quality does not become unstable due to welding heat. Furthermore, even when the thickness of the bimetal 1 is different, the joining can be performed without any trouble.

  FIG. 4 is an explanatory diagram of the internal structure of the circuit breaker incorporating the bimetal of the above-described embodiment. The load-side terminal 16 and the upper end of the heater 2 are connected by a stranded wire 17. A fixed contact 19 is provided on the lower surface of the fixed contact mounting member 18. When an overcurrent flows through the circuit in the ON state shown in FIG. 4, the heater 2 generates heat, the bimetal 1 is bent, and the action portion 21 at the tip of the trigger 20 is pushed. As a result, the trigger 20 is swung to disengage the engaging portion of a latch (not shown) provided inside the tripping device 10, and the tripping device 23 rotationally drives the movable contact 24 to shut off the circuit. It is the same as before.

It is a disassembled perspective view of the heater and bimetal which show embodiment of this invention. It is a perspective view which shows embodiment of this invention. It is an expanded view of the heater in other embodiment of this invention. It is internal structure explanatory drawing of the circuit breaker for wiring which shows an example of use. It is explanatory drawing of the conventional rivet joining structure. It is explanatory drawing of the conventional jock junction structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bimetal 2 Heater 3 Cut-and-raised part 4 Hole part 16 Load side terminal 17 Strand 18 Fixed contact mounting member 19 Fixed contact 20 Trigger 21 Action part 22 Bending part 23 Tripping device 24 Movable contact 51 Bimetal 52 Heater 53 Hole part 54 Rivet 55 Heater 56 Jock

Claims (2)

In a joining structure of a plate-like heater that generates heat due to overcurrent and a bimetal that is disposed adjacent to the heater and curves due to the heat generated by the heater, a cut-and-raised portion is formed in one of the heater and the bimetal, and the other A hole corresponding to the cut-and-raised part is formed in the hole, and the cut-and-raised part is inserted into the hole and caulked to join the heater and the bimetal, and the lower part of the heater is fixed to the fixed contact mounting member. In addition, a bent structure at the end of the fixed contact mounting member is extended to a position higher than a portion whose width is narrowed by the cut-and-raised portion of the heater or bimetal .   2. The heater / bimetal bonding structure according to claim 1, wherein the cut-and-raised portions are formed on both sides of the heater or the bimetal in the width direction.

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