JPH0334885Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a gear press arrester using a semiconductor arrester element such as a ZnO element.

FIG. 1 shows the structure of a conventional gear press arrester of this type. That is, the conventional gear press arrester has electrode portions 2A of terminals 2 on both end surfaces of a semiconductor arrester element 1 such as a ZnO element.
It was a structure in which an insulating layer 3 was provided by molding, taping, etc., surrounding the semiconductor arrester element 1 and both electrode parts 2A.

This type of gear press arrester has the advantage of being small and lightweight. Furthermore, as shown in FIG. 2, the limiting voltage-current characteristics are also excellent.

However, gear presses with this structure
When an arrester is used for purposes such as protecting a cable sheath, when a short circuit or ground fault occurs in the cable, the short circuit or ground fault current flows for a long time, so the semiconductor arrester element 1 generates heat due to Joule heat. However, the capacitance will be exceeded, a flashover will occur on the surface of the semiconductor arrester element 1, and the arc energy will momentarily create a high pressure, creating a risk of explosion.

The purpose of the present invention is to provide a gear press arrester that can prevent explosions.

In this invention, one
In a gear press arrester in which the electrode portions of a pair of terminals are connected to each other, and the semiconductor arrester element and both electrode portions are housed in an insulating layer, the distance between the electrode portion of either one of the semiconductor arrester elements and the electrode portion of the semiconductor arrester element is A gas chamber is provided between the semiconductor arrester element and the insulating layer, which are connected via a low-melting point conductive material layer, and a direction in which the electrode part is separated from the semiconductor arrester element when a predetermined temperature is reached is provided in the gas chamber. It is characterized by having a built-in shape memory alloy spring whose shape is memorized so as to press against the body.

An embodiment of the present invention will be described in detail below with reference to FIG. Note that parts corresponding to those in FIG. 1 are designated by the same reference numerals. In the gear press arrester of this embodiment, a semiconductor arrester element 1 such as a ZnO element and both electrode parts 2A are connected via a low melting point conductive material layer 4, respectively. As the low melting point conductive material, for example, solder having a melting point around 100° C. is used. The outer diameter of both electrode portions 2A is larger than the outer diameter of the semiconductor arrester element 1, and a gas chamber 5 is formed between the semiconductor arrester element 1 and the insulating layer 3. Gas chamber 5 is formed along the outer periphery of semiconductor arrester element 1 .
The insulating layer 3 is preferably made of elastic material such as rubber. Inside the gas chamber 5, when the temperature reaches a predetermined temperature, an electrode part 2
Shape memory alloy spring 6 whose shape is memorized so as to press A away from the semiconductor arrester element
is built-in. This shape memory alloy spring 6 has a coil shape, and one end is in contact with the electrode section 2A on one side. Examples of shape memory alloys include
Use a NiTi-based one with a memory return setting temperature of 100°C. An insulating material 7 is provided on the surface of the semiconductor arrester element 1 and on the pressure-receiving surface side of at least one electrode part 2A so that when the shape memory alloy spring 6 extends and contacts both electrode parts 2A, there is no short circuit between both electrode parts 2A. It is being Note that instead of this insulating material 7, the surface of the shape memory alloy spring 6 may be insulated with an insulating material such as insulating rubber.

In such a gear press arrester, in the event of a short-circuit accident in a cable or the like, even if an arc discharges on the surface of the semiconductor arrester element 1 due to the short-circuit current, the gas chamber 5 absorbs the increase in gas pressure, preventing an explosion. It can be prevented. Further, the low melting point conductive material layer 4 is melted by the Joule heat, and the temperature in the gas chamber 5 rises, causing the gas pressure to rise. Due to the gas pressure in the gas chamber 5, pressure is applied to the pressure-receiving surface of the electrode section 2A (the part of the electrode section 2A facing the gas chamber 5) in the direction of separating it from the semiconductor arrester element 1. On the other hand, when the shape memory alloy spring 6 reaches a predetermined temperature, its memorized shape is recalled and expanded, and both ends of the spring 6 come into contact with both electrode parts 2A, and spring pressure is applied to both electrode parts 2A in the direction of separating them from the semiconductor arrester element 1. . Therefore, due to these pressures, the low-melting point conductive material layer 4 in a melted and softened state is cut, peeled off, or flowed down, and the electrical path between the electrode section 2A and the semiconductor arrester element 1 is interrupted, acting as a fuse and cutting off the current. be done. The low melting point conductive material that has melted and flowed down accumulates in the lower part of the gas chamber 5.

In addition, in some cases, flash shorting may occur on the surface of the insulating layer 3, and there is a risk of the insulating layer 3 burning, so apply disaster prevention tape, disaster prevention coating, etc. to the surface of the insulating layer 3.
It is preferable to prevent the spread of fire.

Further, the low melting point conductive material layer 4 may be provided between at least one electrode portion 2A of the semiconductor arrester element 1.

Furthermore, the shape memory alloy spring 6 is made into a rod shape with a dimension longer than the distance between the two electrodes, and a plurality of these are used to give them a linear or dogleg shape shape memory, and are usually bent to provide gas It is housed in a chamber 5 and one end of each is fixed to one electrode part 2A, and when a predetermined temperature is reached, it is returned to the memorized shape and both ends are pressed in a direction to separate the electrode parts 2A on both sides from each other. Alternatively, the electrode section 2A may be separated from the semiconductor arrester element 1 to interrupt the electrical circuit.

As explained above, in the gear press arrester according to the present invention, a gas chamber is formed between the semiconductor arrester element and the insulating layer, so the increase in gas pressure at the time of a short circuit accident etc. is absorbed by this gas chamber, and the insulation It can prevent layer explosion. In addition, since the semiconductor arrester element and at least one terminal electrode are connected via a low-melting point conductive material layer, in the event of a short circuit, this low-melting point conductive material layer acts as a fuse and the electrical circuit cut off,
It is possible to block the flow of overcurrent for a long time and prevent the arrester element from exploding from this aspect as well. Furthermore, in the present invention, a shape memory alloy spring is built into the gas chamber, and when the inside reaches a predetermined temperature, it returns to the memorized shape and applies pressure to the electrode part in the direction of separating it from the semiconductor arrester element, so the electric circuit can be quickly closed. It is possible to perform a shutoff and further improve safety.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a conventional gear press arrester, Fig. 2 is a limiting voltage-current characteristic diagram of a semiconductor arrester element, and Fig. 3 is a longitudinal cross-sectional view of an embodiment of the gear press arrester according to the present invention. . 1... Semiconductor arrester element, 2... Terminal, 2
A... Electrode portion, 3... Insulating layer, 4... Low melting point conductive material layer, 5... Gas chamber, 6... Shape memory alloy spring.

Claims (1)

[Claims for Utility Model Registration] (1) A gear press in which each electrode part of a pair of terminals is connected to both end faces of a semiconductor arrester element, and the semiconductor arrester element and both electrode parts are housed in an insulating layer. - In the arrester, the semiconductor arrester element and one of the electrode parts are connected via a low melting point conductive material layer, and a gas chamber is provided between the semiconductor arrester element and the insulating layer, A gear press arrester characterized in that a shape memory alloy spring having a shape memory is built in the gas chamber so as to press the electrode part in a direction to separate it from the semiconductor arrester element when the temperature reaches a predetermined temperature. (2) The gas chamber is provided along the outer periphery of the semiconductor arrester element, and the outer periphery of the electrode portion is provided with a pressure-receiving surface facing the gas chamber. gear press arrestor.