JPS5941262B2 - electric wire fuse - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric wire fuse that prevents bending due to resin pressure during resin molding of the fuse element and greatly improves fusing characteristics and breaking performance.

In a sealed electric wire fuse, when the fuse body is resin molded, the resin used for the electric wire fuse is
Resins with strong mechanical strength, such as polycarbonate, are used to prevent explosions during shutdown, but these resins have high molding temperatures and high molding pressures, so the fuse body housed in the inner cylinder cannot be used. , when molding in a mold, the frame or cap portions on both sides of the fuse body are strongly suppressed and displaced or deformed due to the injection pressure of high-temperature and high-pressure resin, resulting in bending of the fuse element, or When high-temperature heat cycles are repeated in heat cycle tests and the like, the fuse element may gradually become deformed.

If the fuse element is significantly deformed or bent, the fusing portion of the fuse element may come into contact with the protective container, causing problems such as abnormal fusing characteristics and poor appearance.

The present invention has been developed to prevent such bending of the fuse element and to further improve the explosion-proof performance at the time of interruption.

As shown in Fig. 1, for example, on both sides of the central fusing part 1,
A bottomed ceramic tube 5 having a terminal through hole 4 at the center of the bottom is attached to the terminal parts 3 on both sides of the fusing part 1 of the fuse element, which has the terminal part 3 in which the breaking part 2 is formed in a part. After each insertion, the terminals 7 of the terminal section 3 are positioned outside the tube and inserted into the thick ceramic tube 6 with the fused portion 1 side facing, and both ends of the ceramic tube 6 and the ends 7 of both terminal sections 3 are inserted. Each capped terminal 8 is capped and sealed with an inorganic heat insulating material 10 interposed therebetween, and the wire connection terminal portion 11 of the cap terminal 8 and the end portion 7 of the terminal portion 3 of the fuse element are hermetically sealed by crimping or soldering, or both. The fuse body is hermetically sealed in a resin mold 12 or a resin case 12 with its electric wire connection terminal portions 11 protruding from both sides.

It is convenient to use transparent glass tubes as the bottomed ceramic tube 5 and the thick ceramic tube 6, since it is convenient to see through from the outside to see if the internal fuse element is blown.

In addition, the smaller the clearance between the terminal through hole 4 of the bottomed ceramic tube 5 and the terminal portion 3 of the fuse element, the more the fuse element can be supported in the center of the ceramic tube 6 without play, which helps prevent bending. Similarly, it is desirable that the clearance between the bottomed ceramic tube 5 and the ceramic tube 6 be small in order to prevent bending of the fuse element.

Furthermore, the bottomed ceramic tube 5 is interposed between the fusing part 1 and the organic heat insulating material 10. In this case, if the inorganic heat insulating material 10 is made of a buffering material such as ceramic paper, the bottomed ceramic tube 5 is It is closely interposed between the fusing portion 1 and the inorganic heat insulating material 10 for cushioning purposes, and is effective in preventing the bottomed ceramic tube 5 from rattling.

Next, as shown in FIG. 2, a reinforcing plate 9 made of iron or stainless steel or the like is inserted into the inner bottom of the cap of the capped terminal 8 to form a double bottom. By inserting an inorganic heat insulating material 10 inside the cedar and reinforcing the cap part from the inside, when molding the fuse body with resin, the cap part of the capped terminal 8 is injected into the mold by resin pressure inside the mold. This is further effective in suppressing deformation of the fuse element and preventing white spots on the fuse element.

Furthermore, if the resin mold 12 of FIGS. 1 and 2 is made transparent together with the ceramic tube, it is convenient to check from the outside whether or not the fuse element is fused.

With the above structure, as shown in FIG. 1, the bottomed ceramic tube 5 can be fixed between the fusion section 1 in the ceramic tube 6 and the inorganic heat insulating material 10, and the terminal can be passed through at the center of the bottom. Since the terminal portions 3 on both sides of the fusing portion 1 are placed in the center of the ceramic tube 6 through the holes 4, the bottomed ceramic tube 5 prevents bending of the fuse element due to suppression during resin molding, heat cycling, etc. This can be prevented because the terminal parts 3 on both sides of the fusing part 1 are supported, and there is no abnormality in the fusing characteristics and no defects such as bending in appearance.

Furthermore, when shutting off, the bottom of the bottomed ceramic tube 5 is turned off.
The fusing section 1 of the low melting alloy is temporarily shielded from the interrupting arc heat of the interrupting section 2, thereby preventing instantaneous gasification and an increase in the interrupting gas pressure. 5 and the ceramic tube 6, and the capped terminal 8 is insulated by the inorganic heat insulating material 10, so the resin mold 12 or the resin case 12 is completely thermally protected from arc heat. There is no gas generation due to resin burnout.

Turning around, the resin case 12 or the resin mold 12
In addition to making the explosion-proof structure easier by reducing the explosion-proof load, the entire area around the fuse element is protected with inorganic material, which prevents burnout and carbonization of the resin inner wall and adhesion of burnt gas to ceramic tubes, etc. None <, between both terminals of the disconnection part,
The insulation resistance value is also over 100MΩ at 500V megger.
This shows good results.

As described above, this electric wire fuse prevents bending of the fuse element due to resin pressure during high-temperature, high-pressure molding of the fuse element using the bottomed ceramic tube 5, and prevents abnormality in fusing characteristics. Explosion prevention is made easier by reducing the gasification of the resin mold or resin case, and by eliminating the superposition of burnout gas pressure, it is even easier to achieve explosion protection. This eliminates any adhesion to the tube and greatly prevents a decrease in insulation resistance between terminals.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing a partial cross section of the electric wire fuse of the present invention. 1 is a fusing part, 2 is a breaking part, 3 is a terminal part, 4 is a terminal through hole of a bottomed ceramic tube 5, 5 is a bottomed ceramic tube, 6 is a ceramic tube, 7 is an end of the terminal part 3, 8 1 is a terminal with a cap, 9 is a reinforcing plate, 10 is an inorganic heat insulating material, 11 is a wire connection terminal of the terminal with a cap 8, and 12 is a resin mold or a resin case.

Claims (1)

[Scope of Claims] 1. A fuse element having a terminal through-hole at the center of the bottom of the terminal part on both sides of the fusing part of a fuse element having a terminal part partially formed with a cutoff part on both sides of the central fusing part. After inserting the bottom ceramic tubes with their bottoms facing the fusion section, insert them into the thick ceramic tube with the ends of the terminals positioned outside the tubes, and insert both ends of the ceramic tubes and both terminals. A terminal with a cap is attached to the end of the capped terminal with an inorganic heat insulating material interposed therebetween, and the wire connecting terminal part 1 of the terminal with a cap is sealed.
1 and the fuse body, in which the ends of the terminals of the fuse element are hermetically connected by crimping or soldering, or both, and the wire connection terminals are made to protrude on both sides, and the fuse body is hermetically sealed in a resin mold or a resin case. A wire fuse featuring 2. In the electric wire fuse of claim 1, a reinforcing plate that closely contacts the inner bottom of the cap is inserted between the inner bottom of the cap of the capped terminal of the fuse body and the inorganic heat insulating material to form a double bottom, and the bottom of the cap is A wire fuse characterized by reinforcement from the inside.