JPH059885B2 - - Google Patents

Description

[Detailed description of the invention]

This invention provides a sintered electrical contact material that has high hardness, that is, excellent wear resistance, and is rigid.
The present invention relates to a method for manufacturing an electrical contact piece for a switch, which has an extremely strong bond to a main body made of Cu or CU alloy, and is used in oil, air, and gases such as sulfur hexafluoride. Generally, for example, an electric contact A illustrated in a schematic perspective view in FIG. 1 is used in an oil-submerged switch. This electrical contact is usually made by cutting a cylindrical electrical contact piece material of a predetermined shape from a round bar or tube material of Cu or Cu alloy such as pure copper, brass, or chromium-copper alloy, and attaching it to one end edge of the material. Ring-shaped Cu-W alloy, Cu-WC alloy, Ag-
After brazing a highly rigid sintered electrical contact material made of W alloy or Ag-WC alloy,
It is manufactured by the main process of vertically dividing it into four electrical contact pieces. In addition, in FIG. 1, 1 is an electric contact piece, 1a is an electric contact piece main body, and 2 is a sintered electric contact material. However, in the electrical contact piece manufactured by this conventional method, wear progresses relatively easily due to its low hardness, and moreover, the sintered electrical contact material 2
Since it is simply bonded to the Cu or Cu alloy main body 1a by brazing, the electrical contact material often peels off under severe conditions, making it impossible to use it later. Since the manufacturing process is mainly based on cutting, the material yield is extremely low, and a large number of man-hours are required, resulting in high costs. In addition, as seen in Japanese Patent Application Laid-Open No. 119674/1983, an electric contact piece material for a switch having a predetermined shape is produced by one-time pressing of an electric contact piece material to which the above-mentioned sintered electric contact material is brazed. Although the manufacturing method is also known, the electrical contact piece for a switch manufactured by such a manufacturing method has not only the brazed part between the sintered electrical contact material and its main body, but also the soldered part between the sintered electrical contact material and the main body part. However, there were also problems such as cracks occurring and a large number of defective products being produced. Therefore, the present inventors conducted research to solve the problems of the conventional electrical contact pieces as described above, and as a result, the inventors developed a long flat plate material of Cu or Cu alloy by extrusion processing, drawing processing, etc. Alternatively, the material is formed by rolling into a long material with a cross-section of A Cu or Cu alloy electrical contact piece material is created by brazing a rigid sintered electrical contact material along one edge of the inner surface of the processed material. When the inner surface is formed into a concave surface containing the sintered electrical contact material by pressing, the resulting electrical contact piece is work hardened by the pressing and has a significantly high hardness. Since the sintered electrical contact material is compressed and sandwiched between the Cu or Cu alloy on the back, the bond is extremely strong, and there is almost no material loss. They discovered that this method does not produce defective products due to cracks occurring between the wires or in the sintered electrical contact material itself, and is superior in mass production, resulting in significantly lower costs. This invention was made based on the above findings, and will be specifically explained below using Examples. Example A long flat strip made of 1/2 copper, 2 types of brass, and chromium copper, respectively, was formed by drawing into a long material with the cross-sectional shape shown in the schematic perspective view of Fig. 2, and then this A long material having a cross-sectional shape is cut at a predetermined width at right angles to the longitudinal direction to form a processed material shown in FIG. After cutting the part (indicated by the two-dot chain line in the figure), 30% Cu−
70% W alloy, 50% Cu-50% WC alloy, 35% Ag-
Sintered electrical contact materials with high rigidity of either 65% W or 50% Ag-50% WC alloy (weight% or more) are brazed using silver solder in the combinations shown in Table 1. The electrical contact of the present invention, which is then shown in a perspective view in FIG. Child pieces 1 to 6 were each manufactured. Note that, as shown in FIG. 4, the electrical contact piece 1 manufactured as a result is composed of a main body 1a and a sintered electrical contact material 2, similar to the conventional one. In addition, for the purpose of comparison, the above-mentioned conventional method was used, that is, a cylindrical electrical contact piece material of a predetermined shape was cut out from a tube made of the same material, and one end edge of the inner surface of this material was made of the same material. The main process is to braze any of the ring-shaped sintered electrical contact materials in the combinations shown in Table 1 with silver solder, and finally cut them vertically into four electrical contact pieces.
Similarly, conventional electrical contact pieces 1 to 6 having the shapes shown in FIG. 4 were manufactured, respectively. Next, regarding the electrical contact pieces 1 to 6 of the present invention and the conventional electrical contact pieces 1 to 6 obtained as a result,
The Vickers hardness (load: 1 kg) was measured at predetermined points on the side surface, that is, at points A to F on the electric contact piece shown in the side view in FIG. The results are shown in Table 1, and the electrical contact pieces 1 to 1 of the present invention
It is clear that all of No. 6 are work-hardened by press molding and have higher hardness than conventional electrical contact pieces. In addition, when these electrical contact pieces were incorporated into an oil submerged switch and a practical test was conducted,
The electrical contact pieces 1 to 6 of the present invention all passed the load switching, short-time current, and closing current tests,
In contrast, the sintered electrical contact material did not peel off at all, showed excellent wear resistance, and showed no deformation.

[Table] Conventional electrical contact pieces 1 to 6 wear out relatively quickly, and peeling of the sintered electrical contact material was also observed. These results were similar in practical tests conducted in the air and in sulfur hexafluoride gas. In the above embodiments, the electrical contact piece material was manufactured from a drawn strip, but it can be similarly manufactured from an extruded or rolled strip. As mentioned above, according to the method of this invention, Cu
Alternatively, a long flat plate of Cu alloy is formed into a long material with a cross-sectional shape by plastic working, and then this long material is cut into a predetermined width at right angles to the longitudinal direction to produce a processed material. , it is possible to produce electrical contact pieces with a deeper shape than conventional ones, and also has high hardness, and the brazed sintered electrical contact material is compressed by the back Cu or Cu alloy body. Since the electrical contact pieces are sandwiched together, the connection is extremely strong, and it is possible to manufacture the electric contact pieces with almost no material loss and with good mass productivity. When used, it not only shows excellent wear resistance but also provides industrially useful hardening that exhibits stable performance over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of an electric contact, FIG. 2 is a schematic perspective view showing a long material with a cross-sectional shape in an embodiment of the invention, and FIG. 3 is a perspective view showing a processed material in an embodiment of the invention. 4 is a perspective view of the electric contact piece, and FIG. 5 is a side view of the electric contact piece. In the drawings, A... Electric contact, 1... Electric contact piece, 1a
... Electric contact piece body, 2... Sintered electrical contact material.

Claims (1)

[Claims] 1. A long flat plate of Cu or Cu alloy is formed into a long material with a cross-section of A processed material is prepared by cutting the processed material, and then a rigid sintered electrical contact material is brazed along one edge of the inner surface of the processed material obtained by cutting Cu or Cu. An electrical contact piece material made of an alloy is produced, and the electric contact piece material is press-worked to form the inner surface into a concave surface containing the sintered electrical contact material, which has high hardness. A method for manufacturing electrical contact pieces for switches.