JPS5831297Y2 - current limiting fuse - Google Patents

Description

[Detailed description of the invention] The present invention relates to a current-limiting fuse, and in particular, the arc generated during fusing is suppressed within a slit made of a solid insulator that has no pores or has very few pores and also serves as an arc extinguisher. The present invention relates to a structure of a slit-type current limiting fuse that can significantly increase the arc voltage and improve the current limiting function by confining the fuse compared to conventional fuses.

Various types of fuses have been proposed in the past, but the most commonly used fuses have a structure in which a fusible piece is surrounded by an insulator made of quartz sand or equivalent particulate matter that also serves as an arc extinguisher. have.

However, in a fuse with such a structure,
The above-mentioned insulators generally have considerable pores, so the arc that occurs during current-limiting interruption spreads through the insulator, the arc cross-sectional area increases, and the magnitude of the generated arc voltage is insufficient, resulting in poor current-limiting performance. was insufficient in terms of

Furthermore, when current repeatedly flows through the fuse, the fusible piece is subjected to repeated thermal stress due to expansion and contraction due to heat cycles, which may lead to abnormal wire breakage.

In order to avoid such accidents, conventional fuses use measures such as forming the fusible piece in a spiral or staggered shape, or providing a constriction in a part of the fusible piece to reduce the thermal stress. Although it has a structure that absorbs water, excessive bending of the fusible piece has the disadvantage that it leads to a decrease in reliability, which is not preferred in practice.

In view of the above points, the present invention was developed to solve these problems, and improves the reliability of the pore-forming flow fuse by rationally absorbing thermal stress, especially under the heat cycle of energization. The purpose is to provide current-limiting fuses.

In order to achieve such an objective, the present invention provides a structure in which a surface including a gap formed by a solid arc-extinguishing insulator and a connection point between a pair of electrodes and a fusible piece are on the same plane or on the same axis. The present invention will be explained in detail below based on the drawings.

Figures 1a and 1) are diagrams for explaining the principle of construction of the present invention, and show cross-sections of a slit-type fuse with high current limiting characteristics.

In order to facilitate understanding of the present invention, this will be explained first.

In the figure, a fusible piece 1 is placed in a gap 3 formed by a solid arc-extinguishing insulator 2, and connected to electrode terminals 5a and 5b held by an insulating tube 4.

Reference numeral 6 denotes a hole for holding the arc-extinguishing insulator 92 (%i).

In the current-limiting fuse configured in this way, the arc generated during fusing is confined within the slit 3, so the cross-sectional area cannot become large, and the arc-extinguishing insulator 2 Due to the arc-extinguishing effect of gas generated by exposure to an arc, it generates a much higher ground voltage than conventional fuses.1. South limiting current performance/ability: Indicates.

Therefore, the fusible piece 1 also has the same current rating as the conventional current limiting fuse;
Since it can be made much shorter than the current limiter and the steady resistance value seen from the electrode terminals 5a and 5b can be reduced, it is possible to realize a current-limiting fuse that is small, inexpensive, and suitable for large currents.

Second. The figure is a sectional view showing an embodiment of the pulsating flow crown according to the present invention, and shows the arrangement of the slit and the fusible piece, and the connection between the fusible piece and the electrode. be.

In the figure, 1:, 1. , ' are the fusible pieces, and these are the first
It is connected to electrode terminals 5a, 5p shown in the figure.

As shown in the figure, a pair of electrodes 7 a and 7 b which are connected to the fusible piece and have a φ position among the electrode terminals 5 a and 5 b have an inclination of 79 fq and a groove 8
a, 8 b, and conduct as much as possible, 18 odor, 8
．． They are connected at the bottoms 9a and 9b of b.

At this point, the slit 3ρ plane formed by the arc-extinguishing insulator 2,
Hemp portion 9a at the connection point between fusible piece 1 and electrodes 7a and 7b
, 9b are not on the same plane, the fusible piece 1 when not exposed to heat becomes like the fusible piece 1' shown by the broken line due to thermal expansion, and the thermal stress applied to the fusible piece is alleviated.

Shi・ga 2, - for heat cycle of energization:, 7C
Reliability can be significantly improved.

, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,Fig.

In Part 3A, the same parts as in Fig. 2 are given the same reference numerals to save explanation.

The φ point, which is similar to Fig. 2, connects the fusible pieces 1 and 1' to the projection 10 a.
, IQ,, b); Chio: Ite 1 Drop 1: Pole 7a,
This is because it was connected to 7b.

The operation and effect of alleviating the thermal stress applied to the fusible piece and improving reliability against the heat cycle of energization are completely the same as in FIG. 2, and therefore will not be described here.

゛Although the present invention has been explained above using the case where a plate-shaped fusible piece is used as an example, the present invention is not limited to this. The same four effects can be achieved by arranging the electrode and the fusible piece so that the surfaces including the connecting parts are not on the same plane, but are not on the axis. This goes without saying.

,. As is clear from the above description, according to the present invention, the fusible piece can be made to have extreme bends in advance without being damaged by force, absorbing the heat cycle of energization and the force stress under the vehicle. Since the performance can be greatly improved, the practical effect is extremely great.

. In addition, the simple configuration without using complicated means improves current limiting and power, and realizes a small, inexpensive current limiting fuse that is suitable for large currents. It is also effective in that it can be used.

,.

[Brief explanation of drawings]

Figures 1a and 1) are cross-sectional views for explaining the principle of the present invention, and Figure 2! is a sectional view showing one 44 example of the current limiting fuse according to the present invention, and Fig. 3 is a sectional view showing another embodiment of the present invention. ...,・jj l
'1llljl・S・:1'';・Pa11.1'-...
...fusible piece, 2...arc-extinguishing property, ash camphor, material, 3
...,..., -slit, 7 a,,7 b...stomach...
Electrodes, 9, a, , 9 b---bottom.

Claims (1)

[Scope of utility model registration request] In a fuse including a fusible piece provided in a slit formed of a solid arc-extinguishing insulator and connected to a pair of electrodes, the surface including the slit is the same as the connection point between the electrode and the fusible piece. A current limiting fuse characterized in that it is arranged not on a plane or on the same axis.