JPS5853456B2 - electric wire fuse - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire fuse with improved breaking performance and airtightness.

Conventional wire fuses come in partially open/f-type, which releases the cutoff gas pressure into the fuse tube material when cut off due to a short circuit, and sealed types, but partially open types produce a loud explosion sound when cut off. In addition, since it is a partially open type that releases a shutoff gas and is preferable for environmental safety, there is a risk that the fuse element will become contaminated and deteriorate due to salt damage in a polluted atmosphere or in coastal areas.

In addition, for sealed types, in order to contain the explosive power at the time of interruption, methods such as using thick resin such as strong polycarbonate, creating a double structure, or filling the interruption section with arc extinguishing agent are used. , had been taken.

However, because it is completely sealed, large gas pressures are generated due to the metal gas of the element when shutting off and the combustion gas on the resin surface due to the high heat during shutoff, and it is difficult to create a structure that can withstand this. Due to carbonization, there were drawbacks such as a decrease in insulation resistance between both terminals of the fuse (more than 0.2MΩ at 500V).

Furthermore, in an airtight box, it has been difficult to completely prevent moisture from being sucked in due to air entering and exiting from the joints due to heat cycles.

The present invention greatly suppresses the cutoff gas pressure at the time of cutoff, facilitates complete sealing of the wire fuse, greatly suppresses the decrease in insulation resistance after cutoff, and significantly improves airtightness. As shown in the drawing, a fuse element 3 is inserted into a ceramic tube 2 with both rounded portions 1 narrowed, and both terminal portions 4 of the fuse element 3 are made to protrude outside the ceramic tube, and then inserted. A metal connection terminal 7 having a cap part 5 that fits into the mouth part 1 of the ceramic tube 2 and a terminal connection hole 6 of the fuse element 3 on one side, and a wire insertion connection hole 10 separated by a partition wall 9 on the other side. are fitted to both terminal portions 4 of the fuse element and both mouth portions 1 of the ceramic tube 2 through heat insulating material 11, and adhesively sealed to the mouth portion 1 at the camp portion 5. , the outside of the fuse body a, in which the terminal portion 4 of the fuse element 3 and the terminal connection hole 6 are crimped and connected, is covered with a resin mold 8 with the electric wire connection portion 7' of the connection terminal 7 protruding.

In the drawings, the heat insulating material 11 is interposed within both eye portions 1, but a heat insulating material such as a plate-shaped ceramic paper may be interposed between the mouth portion 1 and the bottom of the camp portion 5 (7A'i).

Further, instead of the resin mold 8, it may be covered with a resin case, a heat shrink tube, or the like.

7.b. By using a thick transparent glass tube as the ceramic tube 2 and using transparent resin as the resin mold or resin case, it is possible to see through from the outside to check whether the fuse element is broken or not. It can be done.

With the above structure, in the electric wire fuse of the present invention, the fuse element 3 is covered with an inorganic ceramic tube 2 or a thick glass tube, and both sides of the cefmic tube 2 are covered with metal through an inorganic heat insulating material 11 such as ceramic paper. Since the connecting terminal 7 is covered with the cap 5, there is no chance that the resin will be directly exposed to the arc heat during shutoff.

For this reason, like conventional resin containers, it receives arc heat,
The inner surface of the resin container burns out instantaneously, gasifies, and generates a very large gas pressure, which causes the resin container to rupture due to a large load applied to the cutoff gas of the fuse element 3 itself, or the stopper to break off when disconnected. The explosive force is greatly reduced, and therefore the strength of the case is also reduced, and it can be sealed without the need to pin the stopper to the case.

In addition, since the resin and the inner surface of the container are not carbonized, there is no drop in the insulation resistance between the two terminals of the breaker, and the most problematic problem in sealing electric wire fuses, which is a countermeasure against breaker, can be solved with a simple structure. It has excellent functions such as being completely explosion-proof and greatly reducing the strength of resin explosion-proof containers.

Note that some conventional electric wire fuses have a double structure using glass tubes, but the plugs on both sides of the glass tube are made of resin, or the glass tube is thin, so the arc heat when it is cut off can damage the glass tube. It penetrates instantly and burns out the inner surface of the resin outer tube.
Since the resin gas pressure generated at this time cannot be easily suppressed, a strong container that can withstand the gas pressure is required, and an arc extinguishing agent or the like is required at the interrupting part. Inorganic tubes such as thick glass tubes or cap portion 5
The insulation material 11 is used to block the arc heat, so the resin is not burnt out due to the arc heat when the short circuit is interrupted, and the resin burns out.
There is no gas pressure caused by loss, no arc extinguishing agent is required, and the fuse element can be easily sealed in an explosion-proof manner.

The power fuse of the present invention has a feature that it can be applied to fuse elements of all types of structures.

[Brief explanation of the drawing]

The drawing is an explanatory cross-sectional view of the electric wire fuse of the present invention. 1 is a mouth part, 2 is a ceramic tube, 3 is a fuse element, 4 is a terminal part, 5 is a cap part of the connection terminal 7, 6 is a terminal connection hole, 7 is a connection terminal, 7' is a power connection part of the connection terminal 7 , 8 is a resin mold, 9 is a partition wall, 10 is an electric wire insertion connection hole, and 11 is a heat insulating material.

Claims (1)

[Claims] 1. A fuse element is inserted into a ceramic tube with both mouths narrowed, with both terminals thereof protruding outside the tube, and a cap part that fits into the mouth of the ceramic tube is provided on one side. A metal connection terminal, which has a terminal connection hole for the fuse element and a 6-person connection hole for electric wires isolated on the other side, is attached to both terminal parts of the fuse element and both parts of the ceramic tube, and both parts are insulated. The wires are fitted together through the material and sealed with adhesive at the cap part, and the terminal part of the fuse element is crimped and connected to the wire fuse body.The wire connection part is made to protrude from the outside of the fuse body, and the wire connection part is housed in an insulating coating or a resin case. A wire fuse characterized by: 2. Insert the fuse element into a thick transparent glass tube with both mouths narrowed, with both terminals protruding outside the tube, and attach the cap part and fuse element that fit into the mouth of the transparent glass tube on one side. A metal connection terminal having a terminal connection hole and a wire insertion connection hole isolated from the other side is attached to both terminal parts of the fuse element and both parts of the transparent glass tube, with a heat insulating material interposed between both parts. The wires are fitted together and sealed with a cap, and the wire connection portion is made to protrude from the outside of the wire fuse body with the terminal portion of the fuse element crimped and connected, and the wire connection portion is housed in a transparent insulating coating or a transparent resin case. A wire fuse featuring: