JPH029416B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a wire fuse that can reliably cut a large current without damaging its airtight structure. In recent years, with the increase in the capacity of load equipment, it has become necessary to ensure a large shearing capacity for electric wire fuses, resulting in an increase in the gas pressure within the closed container, which has caused the problem of the container breaking. Therefore, electric wire fuses were devised in which a weak part was provided in a part of the container and a separate pressure relief mechanism was provided.
In these cases, the structure was complicated, special processing was required, and there were various drawbacks in terms of assembly. On the other hand, since this type of electric wire fuse is used by being directly connected to electric wires, there is a problem that if the internal airtightness is not maintained, the fuse may fall irreversibly due to water ingress, etc. There is also a need for retention. The present invention provides an electric wire fuse that solves the above-mentioned problems, and when a large current exceeding a predetermined value is cut off, the gas pressure inside the container causes the part that is kept airtight in a steady state to It is characterized by being designed to release gas pressure to the outside as a pressure relief hole, and is characterized by having both airtightness and pressure relief at the same time, having a simple structure, and being able to reliably cut off large currents. It is something. The specific configuration of the present invention will be described below with reference to the drawings. One end of the insulating outer cylinder 1 made of transparent synthetic resin such as polycarbonate is closed, and a wire connection terminal insertion hole 1a is bored in the center of the closed portion to form a wire connection terminal support portion on one side. A support tube 3 having a wire connection terminal insertion hole 3a is fitted into the other end opening 2 of the insulating outer cylinder 1 to form the other side wire connection terminal support portion. The insertion holes 1a and 3a at both ends of the insulating outer cylinder 1 are provided with wire connecting portions 4a and 5a outward.
Wire connection terminals 4 and 5 are provided in a protruding state. A concave groove 6 is carved in the center of the outer end of the insulating outer cylinder 1 on the closed side side, and a pin 7 is driven through a part of the wire connection terminal 4 so as to be inserted into the concave groove. It will be done. On the other hand, on the opening side of the insulating outer cylinder, a groove 8 is carved in the center of the outer end of the support cylinder 3, which is fitted so that a part thereof fits into the inner periphery of the insulating outer cylinder. , the pin 9 is driven in by the same means as described above. Concave grooves 6, 8
The terminals are prevented from rotating by pins 7 and 9, respectively. Protective covers 10 and 11 are capped and adhered to both ends of the insulating outer cylinder 1, respectively, and the circumferential groove between the inside of the protective covers 10 and 11 and the insulating outer cylinder and the wire connection terminal is filled with a filler such as silicone rubber. glued,
It has a double airtight structure to the outside. Further, on the inner circumferential surface of each of the wire connection terminal insertion holes 11a of the protective cover 11 located on the same side as the wire connection terminal insertion holes 3a of the support tube 3, a discharge hole groove 3b and a discharge hole groove facing in the axial direction are provided. 11b, and the inside of the insulating outer cylinder 1 and the outside of the electric wire fuse are communicated through these discharge hole grooves 3b and 11b, thereby forming a gas pressure discharge hole. The gap between the groove 11b of the protective cover 11, which constitutes a part of the gas pressure release hole, and the outer peripheral surface of the wire connection terminal 5, or the gap between the gap and the groove 3a of the support tube 3 and the wire connection terminal 5.
The entire gas pressure release hole, which consists of the gap between the outer circumferential surface of the Sealed. Furthermore, by providing this gas pressure release hole on the closed side of the insulating outer cylinder, the pressure release effect can be further enhanced. Next, the structure of the fusible body part F will be explained.
The fusible body part is composed of a series connection of a high current shield section and a small current shield section, and the entire fusible body part is made of transparent heat-resistant glass arranged with a slight gap from the insulating outer cylinder 1. It is housed in an insulating inner cylinder 12 made of a tube or the like. First, the large current sheath breakage is caused by a plurality of constrictions 13a.
High-temperature fusible portion 13 with a difference in cross-sectional area by providing
, one end is a support plate 1 made of ceramic paper or the like.
9 and the packing, and the other end thereof is connected to the center of the electric wire connecting terminal 4 by caulking, brazing, etc., to the connector 14. To create a small current break, connect a low-temperature fusible material 16 between the connector 14 and the other connector 15 by soldering or brazing, and connect the conductor 17 led out from one end of the connector 15 with ceramic paper or the like. The position is regulated by the partition plate 18 made of
Fix it in the center using caulking, etc. Note that the space A formed between the partition plate 18 and the support cylinder 3 in the inner cylinder 12 increases the volume of the sealed container by moving the partition plate due to the gas pressure at the time of shrinkage, and also increases the volume of the airtight container. Having a portion with a low degree of contamination contributes to an improvement in dielectric strength. Next, Table 1 shows the comparison results of the shear breakage test between the electric wire fuse of the present invention provided with a discharge hole and the conventional electric wire fuse.

[Table] As is clear from the comparative test results in Table 1, the electric wire fuse of the present invention has almost no difference in breaking current of about 3000A compared to conventional fuses, but In this case, it can be seen that the effect is clearly evident. It should be noted that there was almost no difference between the case where the grooves as discharge holes were provided on both sides and the case where they were provided on only one side, and the results were good in both cases. The electric wire fuse of the present invention has a gas pressure release hole in the penetrating portion of the wire connection terminal, and by filling the gas pressure release hole with a soft material, airtightness can be maintained reliably during normal use. At the same time,
When a large current exceeding 5000A is interrupted, the pressure inside the insulating inner cylinder becomes extremely high. Because of this, the abnormal pressure is quickly released to the outside, achieving the intended purpose. Furthermore, even if the released soft part is released to the outside, it is almost in a powder-like state, so there is no concern that it will pose a danger to humans or livestock. In addition, the gas pressure release hole in the present invention is easily formed by a concave groove provided along the wire connection terminal insertion hole of the support tube, etc., and the outer surface of the wire connection terminal, so that it can be easily formed during parts processing work and fuse assembly work. This does not require any special work process. As described in detail above, the present invention has a simple structure and double or triple safety measures, so that accidents caused by breakage of the fuse, personal injury caused by falling damaged objects, etc., failure to cut the fuse, etc. This is an invention that can greatly contribute to industry as a safe and reliable protection fuse that eliminates the factors involved.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of an electric wire fuse embodying the present invention. FIG. 2 is a developed view showing the main parts of the present invention. Figure 3 is A in Figure 1.
-A' sectional view. FIG. 4 is a sectional view taken along line BB' in FIG. 1 as well. Explanation of symbols, 1...Insulating outer cylinder, 3...Supporting cylinder,
1a, 3a... Wire connection terminal insertion hole, 4, 5...
Wire connection terminal, 10, 11...protective cover, 3
b, 11b...Groove for pressure release hole, F...Fusible body part.

Claims (1)

[Claims] 1. Between a pair of wire connection terminals 4 and 5, connect a fusible part F, which is a series connection of a small current sheath break part made of a low temperature fusible material 16 and a large current break part made of a high temperature fusible material 13, The fusible body part F is located in an insulating cylinder, and one ends of both the electric wire connection terminals 4 and 5 are fixed to both ends of the insulating cylinder with a part of the insulating cylinder or a wire connection terminal support part made of the support cylinder 3. In the electric wire fuse whose other end protrudes outside through the protective covers 10 and 11, the electric wire connecting terminal support portion and the protective cover that are close to the outer peripheral surface of at least one electric wire connecting terminal have an axis line of the electric wire connecting terminal. A gas pressure release hole communicating between the inside of the insulating cylinder and the outside is formed by providing a concave groove extending in the direction and the outer surface of the wire connection terminal, and the gas pressure release hole is sealed with a soft material. electric wire fuse.