JPH0134274Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention particularly relates to an electrode structure in a current limiting fuse for cut-outs.

For example, when assembling a current-limiting fuse for a box-shaped cutout as shown in Fig. 1, a lower electrode is bonded and fixed to an insulating cylinder 1 made of porcelain such as crystallized glass porcelain or fiber-reinforced plastic. Spiral-shaped fusing display resistance wire 3 from the 2 side
An insulating thin tube 6 having a fuse element 4 and a blowout indicator 5 and made of alumina porcelain or the like is inserted and fixed into the insulating tube 1, and then insulated from the upper electrode 7 side adhesively fixed to the insulating tube 1. The cylinder 1 was filled with arc-extinguishing sand 8, and the upper electrode 7 portion thereof was sealed with a sealing member 9. In addition, 20 is an upper contact blade as an upper contact protruding from the upper electrode 7, 21 is a base end fixed to the middle part of the insulating cylinder 1, and a tip part is the same as the upper contact blade 20. A lower contact blade serving as a lower contact protrudes in the direction, and is electrically connected to the lower electrode 2.

Conventionally, however, when assembling these current limiting fuses, a capillary support such as an intermediate electrode 10 as shown in FIG. 3 has been provided inside the upper electrode 7 in order to center the insulating capillary tube 6. Therefore, not only the number of parts increases, but also the assembly work becomes troublesome, leading to a decrease in the efficiency of the assembly work.

Further, even in the current limiting fuse for a cylindrical cutout as shown in FIG. 2, an intermediate electrode 10 as shown in FIG. 4 is required, causing a similar problem. Note that 22 is an upper contact protruding from the upper electrode 7, and 23 is a lower contact fixed to the middle part of the insulating tube 1, and is electrically connected to the lower electrode 2.

In addition, the cut-out current limiting fuse is installed inside a box-shaped or cylindrical porcelain main body insulator, and in consideration of assembly work, the insulating tube may be made thicker to facilitate filling with arc-extinguishing sand. Since it is not possible to accommodate the space inside the main body of the insulator, it is desirable to perform these operations more efficiently with the current dimensions.

This idea was made in order to improve the problems existing in the above-mentioned prior art, and is provided with a support protrusion on the inner surface of the upper electrode for supporting and fixing the outer periphery of a fuse element support such as an insulating thin tube or an insulating core. This eliminates the need for thin tube supports such as intermediate electrodes, which were previously required, reducing the number of parts, making assembly easier, and improving assembly efficiency. Our goal is to provide the following.

The first embodiment of this invention is shown in Figs. 5 and 6 below.
This will be explained according to the diagram. However, members that are the same as or correspond to conventionally known members are given the same reference numerals, and their explanations will be omitted.

This embodiment is an improvement on the upper electrode structure of the conventional current limiting fuse shown in FIG. It is integrally formed to protrude toward the axial direction of the insulating tube 1, and its support protrusion 15 stably supports and fixes the outer periphery of the upper end of the insulating thin tube 6, thereby positioning the center of the insulating thin tube 6. . The arc-extinguishing sand 8 is inserted between the insulating tube 1 and the insulating thin tube 6 through the arc-extinguishing sand storage gap formed between the support projections 15.

Next, the second embodiment will be explained with reference to FIGS. 7 and 8. This embodiment is an improvement on the upper electrode structure of the conventional cylindrical cut-out current limiting fuse shown in FIG. Similarly to the first embodiment, three support protrusions 15 are integrally provided on the inner peripheral surface of the opening of the upper electrode 7 at equal intervals, and gaps for storing arc-extinguishing sand are provided between the support protrusions 15. is formed and operates in the same manner as in the previous embodiment.

As described in detail above, this invention has three supporting protrusions facing the axial direction of the insulating cylinder for supporting and fixing the outer periphery of the fuse element support to the inner surface of the upper electrode, and integrally spaced from each other at equal intervals. By providing arc-extinguishing agent storage gaps between adjacent support protrusions, it is possible to omit thin tube supports such as intermediate electrodes that were conventionally required for center positioning of the fuse element support. It is possible to reduce the number of parts, and
During assembly, arc-extinguishing sand can be inserted through the arc-extinguishing sand storage gap after the fuse element support is centered using the support protrusion, making it easy to move around the fuse element support without changing the conventional design dimensions. Not only can arc-extinguishing sand be filled uniformly into the arc-extinguishing sand, but also, unlike the conventional method, the centering of the fuse element support body does not go out of order when attaching the upper electrode to the insulating tube, which has an excellent effect of improving assembly work efficiency. play.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing conventional current-limiting fuses, respectively. FIGS. 3 and 4 are perspective views showing intermediate electrodes in the current-limiting fuses shown in FIGS. 1 and 2, respectively. The figure is a cross-sectional view of a main part of one embodiment of this invention, FIG. 6 is a cross-sectional view taken along the line X-X of FIG. 5, FIGS.
The figure is a sectional view of the main part thereof, and FIG. 8 is a sectional view taken along the line Y--Y in FIG. 7. Insulating cylinder 1, lower electrode 2, fused display resistance wire 3, fuse elements 4, 11, fused indicator 5, insulating thin tube 6, upper electrode 7, arc extinguishing sand 8, insulating core 1
2. Support protrusion 15, lid portion 16.

Claims (1)

[Claims for Utility Model Registration] Upper and lower electrodes are provided at both ends of the insulating tube, an upper contact is protruded from the upper electrode, and an intermediate portion of the insulating tube is electrically connected to the lower electrode. In the current limiting fuse, a fuse element support having a fuse element and a fuse element support having a blown resistance wire is inserted and fixed into the insulating cylinder, and the fuse element support is connected to the inner surface of the upper electrode. Three supporting protrusions for supporting and fixing the outer periphery of the insulating cylinder are provided integrally at equal angles to each other toward the axial direction of the insulating cylinder, and a gap for storing an arc extinguisher is provided between adjacent supporting protrusions. An electrode structure in a current-limiting fuse characterized by: