JPS5853455B2 - electric wire fuse - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric wire fuse that improves the reliability of fusion bonding between a low alloy alloy and a fused portion of a terminal, and has improved fusing characteristics and breaking characteristics.

The fuse element of a conventional electric wire fuse using a low-fusion metal as a fusing part is a terminal 10 having a large-diameter head 2, and a low-fusion metal 3 butted and fused to the head 2, as shown in Fig. 1. However, in this butt fusion, the head 2F
c When the low alloy metal 3 is fused, the fused part is as shown in Figure 1, the molten low alloy metal 3 spreads around the surrounding area of the low alloy metal 3 and is fused, so that it appears completely. However, the center of the low alloy alloy 3 may not be fully fused, resulting in a partial fusion failure. In this case, it is difficult to detect from the outside, and it cannot be detected by resistance measurement. However, it did not appear as a difference in resistance value, making it difficult to detect.

The present invention improves the reliability of the fused part by completely eliminating such partial incomplete fusion inside the fused part, and also greatly reduces the explosion power at the time of breaking, thereby achieving excellent breaking characteristics. It provides airtightness.

As shown in FIG. 2, an end portion 14 of a conductor wire 6 such as a copper wire having a narrow portion 7 in a part is heated, and a low-alloy metal 4 is placed on both sides of a low-alloy metal 4 such as a rod-shaped lead alloy. is melted and welded as it is to form a fuse element a, and both eyes of this fuse element a are narrowly squeezed, and
Inside a ceramic tube 8 having a lid stopper 16, both terminal portions 9 are made to protrude outside the tube and are sealed with a metal cap 10 via a heat insulating packing 17.

The metal cap 10 is made of copper, brass, aluminum, etc. and has an insertion hole 11 for the terminal portion 9 in the center of the cap.The terminal portion 9 is inserted through the cap 10 as shown in FIG. 2 to cover the ceramic tube 8. Wrap it around the stop 16.

At this time, the mouth of the ceramic tube 80 is insulated with an inorganic heat insulating packing 17 such as ceramic paper.

Although the heat insulating packing 17 in FIG. 2 is inserted into the mouth of the ceramic tube 80, it can also be inserted as a plate-shaped heat insulating packing between the metal cap 10 and the mouth of the ceramic tube 8, and furthermore, the two can be May be used together.

Next, the insertion protrusion 12 of the cap 10 is crimped and sealed, or the fitting portion between the insertion hole 11 and the terminal portion 9 is soldered.

Although FIG. 2 shows the cap 10 having the insertion protrusion 12, a cap without the insertion protrusion 12 may also be used.
In this case, the fitting portion between the insertion hole 11 and the terminal portion 9 is soldered.

Also, instead of soldering, it can be made airtight by using heat-resistant adhesive.

Next, the wire connecting terminal 13 is connected to the terminal portion 9 by crimping or soldering to form a fuse body, and the wire connecting portion 13' of the wire connecting terminal 13 is projected and coated with an insulating coating 15 of resin.

In this case, instead of the insulating coating 150, it may be covered with a resin container.

In addition, the ceramic tube 8 and the insulating coating 15 are replaced with the thick transparent glass tube 8 and the transparent resin coating 15.
It is also possible to do this.

With the above structure, the conductor wire 6 is placed inside the low alloy alloy 4.
Since the end portion 14 of the metal 4 is heated and the low melting metal 4 is pushed in while being melted, the molten low melting metal forms a bulge 5 at the insertion portion of the low melting metal 4 and the conductor wire 6 and is welded to the conductor wire 6. 6
Since the end portion 14 is welded by pushing deeply into the low alloy metal 4, the welding area is wide and the welding is complete, and as in the case of surface bonding shown in FIG. There is no fear that the peripheral edge will be welded as it is, resulting in incomplete welding, and a very stable fuse element can be obtained.

In addition, a narrow part 7 is provided in a part of the conductor wire 6 to be used as a breaker, but if this is compressed with a compression die having a predetermined cross section, it can be made into a narrow breaker with a predetermined cross section and a predetermined length. , it can be formed very easily and economically, and unlike the conventional terminals, it does not require cutting, etc., as shown in Figure 1.
A fuse element that is very economical and has high welding reliability can be obtained.

In this case, the low-alloy metal 4 can easily provide the desired fusing characteristics by selecting the cross-sectional area size, length, and melting point of the low-alloy metal 4 in the overload protection fusing part in accordance with the required fusing characteristics. can do.

Furthermore, by selecting the cross-sectional area and length of the narrow portion 7 in accordance with the predetermined interrupting characteristics, it is possible to limit the interrupting current within the required interrupting time (about half (1) to several centimeters). But it can be done easily.

Next, in order to completely seal the fuse element with an inorganic substance using a metal cap 10 via a thick ceramic tube 8, for example, a thick glass tube 8, and a heat insulating packing 17,
The inner surface of the resin pipe or plug, such as a conventional resin-explosion-proof electric wire fuse, is burned out due to the arc heat when the circuit is cut off, and the large burnout gas pressure generated at that time causes the resin case to be destroyed and the resin plug to be removed. However, in the present invention, there is no instantaneous burnout of the resin and no gas pressure is applied, so there is no such problem.

That is, the cutoff is performed in the narrow part 7, and the arc heat generated at that time is blocked by the metal cap 10 via the thick glass tube 8 and the heat insulating packing 17, and the insulating coating 15 such as resin is not burned out, so that the gas The pressure decreases greatly,
The pressure of the evaporated gas mainly in the narrow part 7 is very small and does not reach the level of breaking and scattering the glass tube 8.

However, the arc heat only causes cracks in the glass tube 8.
This crack can be prevented from dissipating with the insulating coating 15.

The results of the shredding test also showed that at a cutoff current of 3000 A, the thinly resin-coated glass tube 8 cracked, or no cracks were generated, and the cutoff was completely sealed and protected.

Therefore, unlike conventional wire fuses, the resin coating or resin container does not need to have a strong function of suppressing the explosive force at the time of interruption, and can be made into a very simple and economical structure.

Mata, like conventional electric wire fuses, resin burnout and carbonization,
Since there is no resin burnout gas adhesion, the insulation resistance between both terminals of the breaker is almost 100MΩ or more at 500V megger. In particular, it is an electric wire fuse that has an excellent shutoff function that almost eliminates gas pressure during shutoff.

Furthermore, a metal cap 10 is attached to the lid stopper 16 of the ceramic tube 8.
To prevent winding, a ceramic tube and a metal cap 10 are used.
Adhesion is reliable, has highly reliable airtightness, and has excellent workability without the need to wait for curing unlike adhesive bonding.

In addition, the ceramic tube 8 and the insulating coating 15 are
If you use transparent ones, you can check whether the fuse element is blown or not from the outside.

As described above, the electric wire fuse of the present invention has a simple structure,
It has excellent airtightness, workability, reliability, as well as fusing and breaking properties.In particular, conventional electric wire fuses are made of resin, pre-arc agent or fiber to prevent the explosive force at the time of breaking. In the present invention, instead of using a mechanical mechanism such as a double structure,
We have investigated the source of the gas pressure at the time of interruption, and created a structure to remove it.This is a wire fuse with excellent interruption characteristics that has been improved to the point where the explosion-proof strength can be ignored.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional fuse element, and FIG. 2 is an explanatory sectional view of the electric wire fuse of the present invention. 1 is a terminal, 2 is a head, 3 and 4 are low alloy metals, 5 is a protrusion of low alloy metal 4, 6 is a conductor wire, 7 is a narrow part, 8 is a ceramic tube, 9 is a terminal part, 10 is Cap, 11 is insertion port,
12 is an insertion protrusion, 13 is a wire connection terminal, 13' is a wire connection portion of the wire connection terminal 13, 14 is an end of the conductor wire 6, 15
1 is a resin coating, 16 is a lid stopper of the ceramic tube 8, 1
7 is insulation packing.

Claims (1)

[Scope of Claims] 1. A fuse element which is melted and welded by heating the ends of a conductor wire having a narrow part in a part and melting and welding them on both sides of a low-melting alloy, is narrowed in both parts, and The terminals are inserted into a ceramic tube that has a lid stopper with both terminals protruding outside the tube, and the opening is wrapped and sealed with a metal cap through an insulating material, and the wire connection terminal is connected to the protruding both terminal portions. 1. An electric wire fuse characterized in that the electric wire fuse bodies formed by connecting the electric wires are covered with an insulating coating or an insulating container, with the electric wire connecting portions of the electric wire connecting terminals protruding. 2. A fuse element is formed by heating the end of a conductor wire that has a narrow part and press-welding it on both sides of the low-melting alloy while melting it. Both parts are narrowed and have a lid stop part. Insert the tube into a thick transparent glass tube with both terminals protruding outside the tube, wrap the mouth with a metal cap through an insulating material, and seal the tube. Connect wire connection terminals to each of the protruding terminals. An electric wire fuse characterized in that the connected electric wire fuse body is covered with a transparent resin insulating coating or a transparent resin insulating container with the electric wire connecting portion of the electric wire connecting terminal protruding.