JPH0375972B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a fuse that protects electrical circuits and electrical equipment by cutting off the excessive current by blowing out a fusible element when an excessive current flows through the electrical circuit. It is.

[Conventional technology]

Figures 4 and 5 are, for example,
This is a sectional view showing a conventional fuse shown in Publication No. 37538. In the figure, 1 is an outer cylinder made of porcelain or resin, 2 and 3 are attached to both ends of this outer cylinder 1 so as to be closed, and an electric circuit ( 4 is a terminal member made of copper for connection with a terminal member (not shown), and 4 is an inner cylinder 5 to be described later.
A fusible element 5 made of a low-resistance material such as a silver wire, which is installed inside the outer cylinder 1 and whose ends are connected to the terminal members 2 and 3 and is spirally wound, is installed in the outer cylinder 1 so as to be concentric with the outer cylinder 1. An inner cylinder 6 made of a heat-resistant insulator such as glass cloth installed in the inner cylinder 6 is an arc extinguishing agent made of silica sand filled in the voids in the outer cylinder 1 and the inner cylinder 5.

Since arc-extinguishing performance is better when the arc-extinguishing agent 6 is filled as densely as possible, it is filled using a vibrator. One terminal member 2 has a filling hole 2a for the inside of the inner cylinder 5.
and 2b for the outside are provided. After filling, the filling holes 2a and 2b are filled with appropriate plugs (not shown).
Closed by.

Next, the operation will be explained. If an excessive current such as a short circuit current flows through the fuse, the fusible element 4 will melt. The generated arc is cooled and extinguished by the surrounding arc extinguishing agent 6, cutting off the excessive current and protecting the electric circuit and electrical equipment. The arc that occurred at this time was
Although it is only for a very short time, the temperature reaches several thousand degrees, and if the fusible element 4 is in contact with or close to the outer cylinder 1, the outer cylinder 1 will be destroyed by this heat. Since both ends of the fusible element 4 are fixed to the terminal members 2 and 3, they are held accurately in that position, but the central part is held only by the springiness of the spirally formed part. Since it maintains that position, it is unstable and tends to come into contact with the outer cylinder 1. The inner cylinder 5 acts to isolate the fusible element 4 and the outer cylinder 1, and is made of an air-permeable heat-resistant insulating material such as glass cloth so as not to interfere with the arc-extinguishing action of the arc-extinguishing agent 6. When the cross section is polygonal as shown in FIG. 5, the effect on the arc extinguishing effect is small and the isolation effect is large.

[Problem that the invention seeks to solve]

In the conventional fuse configured as described above, in order to sufficiently fill the arc extinguishing agent 6, the terminal member 2 must be provided with a filling hole for the inside of the inner cylinder 5.
Two parts are required: a and 2b for the outside, and it is also necessary to put plugs in two places after filling. This filling hole 1
In order to achieve this, the length of the inner cylinder 5 is made shorter than the outer cylinder 1 to provide a gap between the inner surface of the terminal member 2 and the upper end of the inner cylinder 5. The movement may rub against the fusible element 4, which is undesirable. In addition, in order to facilitate the fitting and assembly between the inner cylinder 5 and the outer cylinder 1, the inner cylinder 5 is configured to be considerably thinner than the outer cylinder 1, so that the inner cylinder 5 is There was a problem that the fusible element 4 could not be completely held at the center of the outer cylinder 1 in the lateral direction at the center of the outer cylinder 1 in the longitudinal direction.

This invention was made to solve the above-mentioned problems, and it is possible to sufficiently fill the arc-extinguishing agent even with just one filling hole, and the inner cylinder does not move inside the outer cylinder, so that the fusible element does not move. The purpose of the present invention is to obtain a fuse that can hold the fuse precisely at the center of the outer cylinder.

[Means for solving problems]

In the fuse according to the present invention, the end of the inner cylinder is formed diagonally with respect to its axis so that an oblique gap is formed between the end of the inner cylinder and the inner surface of the terminal member, and the axis of the inner cylinder is The inner cylinder is held against the cylinder at the apex of its end.

[Effect]

The fuse in this invention has a diagonal gap between the end of the inner cylinder and the inner surface of the terminal member, so that even if there is only one filling hole, the arc extinguishing agent can flow into the inside or outside of the inner cylinder through this gap, and the fuse can be sufficiently filled. It can be so. In addition, by tilting the axis of the inner cylinder with respect to the outer cylinder and holding the inner cylinder at the apex of its end, the inner cylinder is prevented from moving, and at the same time, the axis of the inner cylinder is tilted with respect to the outer cylinder. Hold the contained fusible element precisely in the center of the barrel.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 to 3, 1 to 4 and 6 are the same as the conventional fuses shown in FIG. 4, so their explanation will be omitted. Reference numeral 7 denotes an inner cylinder made of a heat-resistant insulator such as glass cloth, and both ends 7a and 7b thereof are formed obliquely with respect to the axis. Then, the axis line is tilted with respect to the outer cylinder 1, and the inner cylinder 7 is moved to the upper and lower apexes 7.
It is held at c, 7d.

The filling hole 2a for the arc extinguishing agent 6 is 1 in one terminal member 2.
Only one is provided. Note that the filling hole 2a is filled with arc extinguishing agent 6.
After filling, it is closed by a suitable plug (not shown) in the same way as a conventional fuse.

The fuse of this invention configured as described above is
When the arc extinguishing agent 6 is filled through the filling hole 2a of the terminal member 2, the inner cylinder 7 is filled from the inside of the inner cylinder 7 as well as from the diagonal gap formed between the inner surface of the terminal member 2 and the end 7a of the inner cylinder 7. It also flows out to the outside and is fully filled. In addition, the inner cylinder 7 is held at the upper and lower apexes 7c and 7d to prevent it from moving, and as shown in FIG. is held accurately in the center of the outer cylinder 1.

In the above embodiment, the inner cylinder 7 has a rectangular cross section, but the present invention is also effective for other shapes such as a hexagonal cross section.

〔Effect of the invention〕

As described above, according to the present invention, both ends of the inner cylinder are formed diagonally with respect to its axis so that a gap is formed diagonally between the upper end of the inner cylinder and the inner surface of the terminal member, and Since the axis line was tilted with respect to the outer cylinder and the inner cylinder was held at the apex of its end, one hole for filling arc extinguisher was made.
The arc-extinguishing agent can be sufficiently filled even if the inner cylinder is not moved within the outer cylinder, and the fusible element can be accurately held in the center of the outer cylinder.

[Brief explanation of drawings]

1 to 3 are diagrams showing a fuse according to an embodiment of the present invention, in which FIG. 1 is a cross-sectional view taken along the line -- in FIGS. 2 and 3, and FIG. 2 is a cross-sectional view taken along the line -- in FIG. , FIG. 3 is a sectional view taken along the line -- in FIG. 1.
FIG. 4 is a sectional view showing a conventional fuse, and FIG. 5 is a sectional view taken along the line -- in FIG. 1 is an outer cylinder, 2 and 3 are terminal members, 4 is a fusible element,
6 is an extinguisher, and 7 is an inner cylinder. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. An outer cylinder whose both ends are closed with terminal members, an inner cylinder installed within the outer cylinder, and a spirally wound fusible element whose ends are connected to the terminal member and installed within the inner cylinder. , in a fuse consisting of an arc extinguishing agent filled in the spaces inside the outer cylinder and the inner cylinder, the inner cylinder is arranged such that there is a diagonal gap between the end of the inner cylinder and the inner surface of the terminal member. A fuse characterized in that the end of the cylinder is formed obliquely with respect to its axis, the axis of the inner cylinder is inclined with respect to the outer cylinder, and the inner cylinder is held at the apex of the end.