JPS6161494B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention provides a fuse that protects electrical circuits and equipment by cutting off the fault current by blowing the fuse element in response to the fault current, and in particular stabilizing the arrangement of the fuse element. It's about structure.

When a fault current flows through a fuse, the fuse element melts and generates an arc voltage in the opposite direction to the power supply voltage to cut off the fault current.The magnitude of this arc voltage per unit length is Determined by the shape of the element and the arc extinguishing agent, if the length of the fuse element is short, the required arc voltage cannot be obtained, and the fuse becomes unbreakable, resulting in an explosion. On the other hand, if it is too long, a very high arc voltage will be generated and the insulation of circuits and equipment will be destroyed. Therefore, there is an appropriate length depending on the rated voltage, and the length of the fuse element is set approximately proportional to the rated voltage.

On the other hand, the external dimensions of the fuse need to be large enough to accommodate the fuse element, and the cross-sectional area is usually set roughly proportional to the rated current, and the length is set roughly proportional to the rated voltage. but,
Due to the need to standardize the parts used and share the fuse holder, the outer diameter of the fuse may be standardized to be the same as that of a fuse with a higher voltage rating.For example, the 7.2 ^KV and 3.6 fuses, which are currently widely used in Japan, are The outer diameter dimensions of fuses for ^KVs are often the same. In such cases, the external dimensions of the fuse should be 7.2 ^KV
It is set for 3.6 ^{KV and is too long for 3.6 KV} .
The fuse element and the terminal metal are relayed by a conductive member.

An example of a conventional fuse structure in which the above-described fuse element and terminal metal are relayed by a conductive member is shown in FIGS. 1 and 2.

In the figure, reference numeral 1 denotes an insulating cylinder with a terminal metal 2 attached to both ends, and an opening 2a in the center of the terminal metal 2.
and a terminal metal 2 around this opening 2a.
A connecting portion 2b is formed in which a portion of the fuse is bent inward. The fuse element 3 is formed in a spiral or wave shape, and has one end connected to one end of a band-shaped conductive member 4, and the other end of the conductive member 4 is connected to the connecting portion 2b of the terminal metal 2. An arc extinguishing agent 5 is filled into the opening 2a of the terminal metal 2, and a lid 7 is attached to the opening 2a with rivets 6.

The components include porcelain or resin tube for the insulating tube 1, copper for the terminal metal 2 and conductive member 4, silver for the fuse element 3, silica sand for the arc extinguisher 5, and silica sand for the lid 7. Copper and iron are used.

In conventional fuses having the structure described above, the ends of the thick conductive member 4, which has a large volume, are damaged due to vibrations when filling the arc extinguishing agent 5, vibrations and shocks during transportation or operation of the fuse. may be displaced and come into contact with or approach the fuse elements 3 or the insulating cylinder 1, resulting in a decrease in the blowout performance during operation, and in some cases, failure to blow or an explosion. In order to prevent this, a sufficient distance is provided between the fuse elements 3 and between the insulating cylinder 1, which has the drawback of increasing the external dimensions of the fuse.

This invention was made with attention to the above points, and provides a fuse that does not have the drawbacks of the conventional ones by providing a steady rest at the joint between the fuse element and the conductive member. be.

An embodiment of the present invention will be described below with reference to FIG. 1 is an insulating cylinder, 2 is a terminal metal, 3 is a fuse element, and one end 8 of a wire-shaped or band-shaped conductive member 8 is connected to this fuse element 3.
A is connected to the terminal metal 2 as in the conventional case, but the other end 8b is connected and fixed to a relay terminal 9, and extends from the relay terminal 9 in a radial direction with respect to the axis of the insulating tube 1. Steady rest part 8c reaching the inner surface
is provided. and fuse element 3
The end portion of is connected to the relay terminal 9 or the conductive member 8. That is, a predetermined distance 8 from the end of the conductive member 8
b is connected and fixed to the disc-shaped relay terminal 9, and the steady rest part 8c is bent in the radial direction at approximately right angles to the axis of the insulating tube 1 so that the tip reaches the inner surface of the insulating tube 1. ing.

As for the constituent materials, the conductive member 8 is made of wire or strip copper, and the relay terminal 9 is made of copper in the form of a wire or band.
Copper can be used to connect the fuse element 3 to the conductive member 8, and iron can be used to connect the fuse element 9 to the conductive member 8. The rest of the configuration is the same as the conventional one shown in FIGS. 1 and 2, so the explanation will be omitted.

As is clear from the above, the end of the fuse element 3 of the fuse of the present invention is connected to the relay terminal 9.
Fuse element 3
The distance between them is reliably maintained, and furthermore, since the relay terminal 9 is provided with a steady rest portion 8c that extends in a radial direction with respect to the axis of the insulating tube 1 and reaches the inner surface of the insulating tube 1, the insulation between the fuse element 3 and The required spacing between the tubes 1 is reliably maintained, which prevents damage between the fuse elements due to vibrations during filling with arc extinguishing agent, as in conventional ones, and vibrations and shocks during transport or operation of the fuse. There is no possibility that the product will come into contact with or get close to the insulating tube, resulting in a decrease in cutting performance, inability to cut, or an explosion during operation. Therefore, the distance between the fuse elements and the insulating cylinder can be reduced, and the outer dimensions of the fuse can be reduced.

Note that FIG. 4 shows another embodiment of the present invention, and shows the main parts of the relay terminal and the conductive member.
In this example, the relay terminal 10 has a cylindrical shape,
A plurality of notches 10a are provided from the end thereof and are locally bent in the radial direction with respect to the axis of the insulating cylinder, and the tip reaches the inner surface of the insulating cylinder to form a steady rest part 10b. And conductive member 1
1 is connected and fixed to the relay terminal 10 in a straight state. Even in this case, the same effect as above can be achieved.

As described above, according to the present invention, the spacing between the fuse elements and the insulating cylinder is reliably maintained by the relay terminal and the steady rest, so the external dimensions of the fuse can be reduced. Effects can be obtained.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the structure of a conventional fuse.
2 is a sectional view taken along the line -- in FIG. 1, FIG. 3 is a sectional view showing one embodiment of the present invention, and FIG. 4 is a sectional view showing essential parts of another embodiment of the invention. In the figure, 1 is an insulating cylinder, 2 is a metal terminal, 3 is a fuse element, 8 and 11 are conductive members, 9 and 10 are relay terminals, 8c and 10b are steady rests, and 10a is a notch. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A terminal metal attached to both ends of the insulating tube, and a wire or band-shaped wire or strip having one end connected to the terminal metal and the other end connected to a relay terminal arranged inside the insulating tube. A fuse comprising a conductive member, a steady rest extending from the relay terminal in a radial direction relative to the axis of the insulating cylinder and reaching the inner surface of the insulating cylinder, and a fuse element having an end connected to the relay terminal or the conductive member. . 2 Connected to the relay terminal a predetermined distance before the inner end of the conductive member, and bent in a radial direction from the inner end with respect to the axis of the insulating cylinder, forming a steady rest with the tip extending to the inner surface of the insulating cylinder. Claim 1
Fuses listed in section. 3 A plurality of notches are provided at the end of the cylindrical relay terminal, and a steady rest part is formed in which the tip of the notch is locally bent in the radial direction with respect to the axis of the insulating tube, reaching the inner surface of the insulating tube. A fuse according to claim 1.