JP6007286B2 - Manufacturing method of fuse - Google Patents

Description

  The present invention relates to a method of manufacturing a fuse that melts and cuts off current when an overcurrent (current of a rated value or more) is applied.

  A conventional fuse of this type is disclosed in Patent Document 1. As shown in FIG. 8, the fuse 50 includes a bus bar 51 made of a conductive material and a low melting point metal 60. The bus bar 51 is made of copper. The bus bar 51 is provided with a narrow portion 52 having a smaller cross-sectional area than other portions. The bus bar 51 is integrally provided with a caulking piece portion 53 and a pair of damming portions 54. The low melting point metal (for example, tin) 60 is arranged so as to straddle the narrow portion 52 by the crimping piece portion 53. The low melting point metal 60 is fixed to the bus bar 51 by caulking and is welded to the bus bar 51. The pair of damming portions 54 are arranged at intervals on both outer sides of the low melting point metal 60. The pair of damming portions 54 are intended to dam the molten low melting point metal 60 from flowing in a wide range.

  In the above configuration, when an overcurrent is applied to the bus bar 51, the narrow portion 52 has a greater amount of Joule heat generation than other portions, the low melting point metal 60 is melted, and the melted low melting point metal 60 is the bus bar (copper). It diffuses into 51 and lowers the melting point of copper. As a result, the narrow portion 52 is fused.

JP 2010-92727 A

  However, since the conventional fuse 50 uses the low melting point metal 60 in addition to the bus bar 51, a material cost, a processing cost, and an equipment cost are required. Further, since the low melting point metal 60 is welded to the bus bar 51, equipment for welding the low melting point metal 60 is required. From the above, there was a problem of high cost.

  Therefore, the present invention has been made to solve the above-described problems, and an object thereof is to provide a low-cost method for manufacturing a fuse.

The present invention uses a wire in which strands of a plurality of conductive materials are converged, heats a step of producing a heat spot part having a smaller cross-sectional area than other portions by rolling a part of the wire, and the wire A heat dissipating part producing step for producing a heat dissipating part having a larger surface area than other parts, and an inter-wire welding process for fusing a part where the plurality of the wires of the electric wire are converged, and the heat dissipating part producing step Then, it is the manufacturing method of the fuse characterized by expanding between the said strands of the said electric wire, and making it a large surface area .

  According to the present invention, desired fusing characteristics can be realized by using only an electric wire, and a low melting point metal is not used as in the conventional example. Therefore, the material cost, processing cost, and equipment cost of the low melting point metal are not necessary, and the cost is low.

1A and 1B show a first embodiment of the present invention, in which FIG. 1A is a perspective view of a fuse before covering with an insulating protective layer, and FIG. 1A is a plan view of a fuse before being covered with an insulating protective layer, FIG. 1B is a front view thereof, and FIG. The 1st Embodiment of this invention is shown, (a) is the perspective view of a twisted electric wire, (b) is the perspective view which rolled the center location of the electric wire and produced the heat spot part. FIG. 3 is a fusing characteristic diagram showing the first embodiment of the present invention. It is a perspective view of the fuse which shows 2nd Embodiment of this invention and is covered with an insulating protective layer. FIG. 2A is a plan view of a fuse before being covered with an insulating protective layer, FIG. 2B is a front view thereof, and FIG. The 2nd Embodiment of this invention is shown and it is the principal part schematic of a radiation fin processing apparatus. It is a perspective view of the fuse of a prior art example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
1 to 4 show a first embodiment of the present invention. As shown in FIGS. 1 and 2, the fuse 1 </ b> A is fixed by crimping the electric wire 2, the insulating protective layer 10 (see FIG. 1B) covering the entire outer periphery of the electric wire 2, and both ends of the electric wire 2. The two LA terminals 11 are provided.

  The electric wire 2 is formed of an annealed copper wire in which a plurality of conductive wires 2a are converged. The electric wire 2 is set to a predetermined length. The electric wire 2 is in a straight state by twisting back a plurality of strands 2a. A heat spot portion 3 having a smaller cross-sectional area than other portions is provided at the central portion of the electric wire 2. The heat spot part 3 is produced by rolling the central part of the electric wire 2. On both sides of the heat spot portion 3 of the electric wire 2, a heat radiating portion 4 having a larger surface area than other portions is provided. Each heat radiating part 4 is formed in a shape that is expanded in an arc shape so that a gap is formed between each wire 2 a of the electric wire 2. Thereby, the thermal radiation part 4 is taken as the surface area wider than another location.

  The electric wire 2 is welded between the strands 2a except for the heat radiating portion 4. The wire 2 is fixed in shape by this welding.

  The insulating protective layer 10 is made of an insulating resin. The electric wire 2 is insulated by the insulating protective layer 10.

  Next, a method for manufacturing the fuse 1A will be described. First, as shown to Fig.3 (a), with respect to the electric wire 2 with which the strand 2a of the some electrically conductive material was twisted, the strand of the strand 2a is returned and it is set as a straight state (strand straight process).

  Next, as shown in FIG.3 (b), the center location of the electric wire 2 is rolled using the bonder apparatus, and the heat spot part 3 of a cross-sectional area smaller than another location is produced (heat spot production process).

  Next, the both sides of the heat spot part 3 of the electric wire 2 are expanded in an arc shape so that a gap is formed between the respective strands 2a, and the heat radiating part 4 having a large surface area is produced (heat radiating part production process).

  Next, the whole electric wire 2 is heated using a bonder device. Thereby, between each strand 2a except for between each strand 2a of the thermal radiation part 4 is welded (inter-element welding process). The wire 2 is solidified by welding between the strands 2a (see FIG. 1A).

  Finally, the LA terminal 11 is fixed to both ends of the electric wire 2 by caulking, and the entire outer periphery of the electric wire 2 excluding both ends is covered with the insulating protective layer 10 (see FIG. 1B).

  The fusing characteristics of the fuse 1A manufactured as described above are as follows when compared with the unprocessed electric wire W1 and the electric wire W2 that does not have the heat spot portion 3 but has the heat radiating portion 4 and has an increased surface area. become. As the electric wire 2, an electric wire that has a fusing characteristic in a rare short region (200% energization) within a standard without being processed is used. The fusing characteristic line of the unprocessed electric wire W1 is the W1 characteristic line of FIG. Since the electric wire W2 having an increased surface area has a large surface area where the air and the electric wire 2 are in contact with each other in the heat radiating section 4, the heat dissipation when the temperature of the electric wire 2 rises is large. Thereby, compared with the electric wire W1 without a process, fusing time becomes late | slow in the all energization area | region of an overcurrent. The fusing characteristic line of the electric wire W2 having an increased surface area is the W2 characteristic line of FIG. As a result, the fusing time is within the standard range except for the dead short region (600% energization), but the fusing time is slower than the standard in the dead short region (600% energization).

  In the fuse 1A of the present invention, the amount of heat generated at the heat spot portion 3 is larger than that of the electric wire W2 having an increased surface area. Get faster. Therefore, the fusing characteristic line of the fuse 1A of the present invention is the 1A characteristic line of FIG. Thereby, the fusing time is within the standard range even in the dead short region (600% energization). The fuse 1A of the present invention is capable of protecting at a fusing characteristic of 5 levels without a low melting point metal.

  As described above, the desired fusing characteristics can be realized by using only the electric wire 2, and a low melting point metal is not used as in the conventional example. Therefore, the material cost, processing cost, and equipment cost of the low melting point metal are not necessary, and the cost is low.

  The heat spot part 3 is provided in the center of the electric wire 2, and the heat radiating part 4 is provided on both sides of the heat spot part 3 of the electric wire 2. Therefore, since the temperature rise is suppressed by heat radiation at both outer portions of the heat spot portion 3, the heat spot portion 3 is surely fused.

  The shape of the electric wire 2 is fixed by welding. Therefore, even if vibration or stress is applied to the electric wire 2, the shape of the electric wire 2 does not return to the original twisted electric wire state.

(Second Embodiment)
5 to 7 show a second embodiment of the present invention. As shown in FIGS. 5 and 6, the fuse 1 </ b> B of the second embodiment is different in the configuration of the heat dissipating part 4 </ b> A from that of the above embodiment. That is, the heat radiating part 4A is formed by shape processing of the electric wire 2 itself. The heat dissipating part 4A is deformed into an outer shape in which the heat dissipating fin parts 4a project at two locations along the longitudinal direction of the electric wire 2, and thereby has a large surface area. The heat radiating part 4A is produced using a bonder device. As shown in FIG. 7, the bonder device has a convex upper electrode 21 and a concave lower electrode 22. By sandwiching and heating both sides of the heat spot portion 3 of the electric wire 2 between the upper electrode 21 and the lower electrode 22, the heat radiation portion 4A can be made.

  In the second embodiment, the heat dissipating part 4A does not create a gap between the strands 2a as in the first embodiment, so that it is not necessary to twist a plurality of strands straight back.

  Since the other configuration is the same as that of the first embodiment, the same components in the drawings are denoted by the same reference numerals and description thereof is omitted.

  Also in the second embodiment, similarly to the first embodiment, a desired fusing characteristic can be realized by using only the electric wire 2, and a low melting point metal is not used as in the conventional example. Therefore, the material cost, processing cost, and equipment cost of the low melting point metal are not necessary, and the cost is low.

1A, 1B Fuse 2 Electric wire 2a Wire 3 Heat spot part 4, 4A Heat radiation part

Claims (2)

Using a wire in which the strands of a plurality of conductive materials are converged, a part of the wire is rolled to produce a heat spot part having a smaller cross-sectional area than the other part, and another part of the wire A heat dissipating part preparation step for producing a heat dissipating part having a larger surface area, and a welding step between the strands for welding the portions where the plurality of strands of the electric wire are converged ,
The method of manufacturing a fuse, wherein, in the heat radiating portion manufacturing step, a gap between the wires of the electric wire is widened to increase a surface area . A method for manufacturing a fuse according to claim 1 , comprising:
Prior to the heat spot manufacturing step, a strand straightening step is performed in which the strands of the wires are untwisted so as to be in a straight state.

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