JPH017943Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a contact in a switch equipped with a contact having an arc-resistant material at its tip.

[Prior Art] A contact structure in a conventional switchgear is shown in FIG. 1, and this type of switch has a movable contactor 1 that is reciprocated in the axial direction by an external operating mechanism (not shown). and a fixed contact 3 which is divided into a plurality of parts in the circumferential direction on its outer circumference and presses against the movable contact 1 by a spring 2 or its own elasticity, and the movable contact 1 and the fixed contact 3 has arc-resistant materials 4 and 5 attached to the tips of main bodies 1a and 3a made of current-carrying material, respectively.

Further, it has been proposed to change the axial length of the arc-resistant material so that the interface with the contact body is oblique. (Utility Model Application No. 56-105219) [Problems to be Solved by the Present Invention] In such a conventional structure, the electrical conductivity differs greatly at the interface between the contact body made of a current-carrying material and the arc-resistant material. Sometimes, as shown in Figure 1, when the movable contact 1 moves close to the position where the boundary surfaces with the arc-resistant material come into contact with each other, the current path is concentrated in the part A, and the current-carrying material of the contact body may melt. In addition, the arc that occurs immediately after the movable contact 1 separates from the fixed contact 3 may stick to the contact body at the interface area, causing significant wear and tear on this area and greatly reducing the performance of the switch. It had a great influence.

In addition, even if the interface is made to be inclined, the resistance change at the interface is large, so the current will concentrate in the area where the low resistance parts are in contact with each other, and will eventually reach the contact body in the short part of the arc-resistant material. The drawback is that a large current flows, causing wear and tear.

In view of the above points, the present invention aims to provide a switching contact with less wear and tear.

[Means for solving the problem] For this reason, between the contact body and the arc-resistant material,
An intermediate contact material is provided whose resistance value gradually changes so that the side in contact with the contact body has a resistance value equivalent to that of the contact body, and the arc-resistant material side has a high resistance value equivalent to that of the arc-resistant material.

[Function] For this reason, the resistance value of the contact changes gradually, and even if the contact points of the contacts move during opening/closing, there is no sudden change in resistance, and the smooth resistance value change prevents arcing during opening/closing. prevent.

[Example] Fig. 2 showing a specific example of the present invention will be described.

1 is a movable contact; 3 is a circumferentially divided spring 2;
This is a fixed contact into which the movable contact 1 is inserted and pressed, and each of the contact bodies 1a and 3a is made of a current-carrying material such as copper, and the tip of the contact body 1a, 3a is provided with arc-resistant materials 4, 5 made of copper tandusten or copper carbon.
is attached, and intermediate contact materials 6 and 7 are provided between the contact body and the arc-resistant material.

These intermediate contact materials 6, 7 are the contact body 1a.3a
The side in contact with the contact body 1a, 3a has an electrical resistance equivalent to that of the contact body 1a, 3a, and the resistance value gradually changes, and the side connected to the arc-resistant materials 4 and 5 has a resistance value equivalent to that of the arc-resistant material. For example, copper powder is used as a base material, and the content of tungsten or carbon is gradually increased toward one side, and the material is heated and pressed.

Therefore, when the movable contact 1 is pulled out from the fixed contact 3, the contact point between the contacts moves from the low resistance mutual contact area of the intermediate contact materials 6 and 7 to the high resistance area, and the electrical resistance value increases. Since the resistance increases gradually and there is no sudden change in resistance value, the current transfer to the high resistance part is smooth, and when an arc is generated due to an open circuit, the arc does not stick to the contact body.

[Effects of the present invention] As described above, in the present invention, since the intermediate contact material formed so that the resistance value gradually changes is provided between the contact body and the arc-resistant material, sudden changes in the contact points between the contacts There is no significant change in resistance value, preventing the generation of arcs at the interface between the contact body and the arc-resistant material, reducing wear and tear on the contact, and providing good interruption.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing a conventional contactor structure, and FIG. 2 is a sectional view of a main part showing an embodiment of the present invention. 1 is a movable contact, 3 is a fixed contact, 1a, 3a
is the contact body, 4 and 5 are arc-resistant contact materials, and 6 and 7 are
is the intermediate contact material.

Claims (1)

[Claims for Utility Model Registration] 1. A rod-shaped inner contact and an outer contact that is divided into a plurality of parts in the circumferential direction and slides into pressure contact with the outer periphery of the inner contact, each of which is attached to the tip of the contact body. In a switch provided with an arc-resistant material, between the contact body of the inner contact and the outer contact and the arc-resistant material, the side in contact with the contact body has an electrical resistance value equivalent to that of the contact body. A contact for a switch, characterized in that an intermediate contact material is provided whose resistance value is gradually changed so that the side in contact with the arc-resistant material has an electrical resistance value equivalent to that of the arc-resistant material. 2. The switch contactor according to claim 1, wherein the intermediate contact material is a molded body whose resistance value gradually increases toward the arc-resistant material side. 3. The switch contactor according to claim 1, wherein the intermediate contact material is a laminate in which thin plates having different resistance values are sequentially laminated.