JPH0135455B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in a method for manufacturing an electric contact by welding an electric contact having a ring-shaped projection to a thin spring terminal material. Conventionally, as shown in FIGS. 1a and 1b, an electrical contact 2 having a ring-shaped projection 1 on the periphery of the lower surface,
To make an electric contact by welding to the upper surface of the spring terminal material 3 as shown in FIG. Projection welding was performed by pressing the upper electrode 4'. However, in this method of manufacturing an electric contact,
Electrical contact 2 with ring-shaped projection 1
When welding to the spring terminal material 3, the ring-shaped projection 1 will be Since the spring terminal material 3 is brought into contact with the spring terminal material 3 in a biased manner, current does not flow through the entire ring-shaped projection 1 on average. Therefore, the ring-shaped projection 1 does not melt evenly, and the electrical contact 2 is tilted, resulting in variations in welding strength and defective welding. The present invention has been made in order to eliminate the above-mentioned drawbacks, and it is an object of the present invention to provide a method for manufacturing an electric contact with stable welding strength without tilting of the electric contact. The method for manufacturing an electrical contact of the present invention includes the method of manufacturing an electrical contact in which an electrical contact having a ring-shaped projection is welded to a thin spring terminal material by projection welding. A welding electrode with a hemispherical protrusion on the upper surface is arranged on the opposite side from the contact welding surface, and the welding electrode is placed concentrically with the ring-shaped projection of the electric contact through the spring terminal material. It is characterized by projection welding by bringing the two into contact with each other. In the method for manufacturing an electrical contact of the present invention, a welding electrode having a hemispherical protrusion on the upper surface is arranged on the surface of the spring terminal material opposite to the electrical contact welding surface, and Protrusion welding is performed by contacting the welding electrode concentrically with the ring-shaped protrusion of the electrical contact, by protruding the welding electrode from the ring-shaped protrusion of the electrical contact via the spring terminal material. The spring terminal material is slightly curved by pressing with the upper and lower electrodes, eliminating the mounting accuracy of the upper and lower electrodes, variations in the dimensions of the electrical contacts, and the flatness of the spring terminal material. This is because it is possible to make equal contact without deviation, to average the current flowing during welding, to melt the ring-shaped projection evenly, to eliminate the inclination of the electric contact, and to stabilize the welding strength. In addition, the reason why spring terminal materials are limited to thin walls is that the deformation resistance during electrical contact welding is small and they tend to bend easily, and in addition, the current conduction distance through the spring terminal material is shorter than when using flat welding electrodes. This is because it is longer and reduces thermal fatigue during electrical contact welding. Next, in order to clarify the effects of the method of manufacturing an electric contact according to the present invention, specific examples and conventional examples thereof will be described. Example 1 As shown in Fig. 3, a 10w/oRu spring terminal material 3 made of perylium copper with a wall thickness of 0.15 mm has a ring-shaped projection 1 on the upper surface and a lower peripheral edge thereof.
- An electric contact 2 made of Pd alloy is placed on the lower surface of the spring terminal material 3, and a lower welding electrode 6 is provided on the lower surface of the spring terminal material 3, which has an oval-shaped protrusion 5 having a smaller diameter than the ring-shaped projection 1 of the electric contact 2 at the center of the upper surface. The upper electrode 4' for welding was pressed onto the upper surface of the electric contact 2, and projection welding was performed to obtain an electric contact. Conventional example 1 As shown in Fig. 2, a 10w/oRu spring terminal material 3 made of perylium copper with a wall thickness of 0.15 mm has a ring-shaped projection 1 on the upper surface and a ring-shaped projection 1 on the periphery of the lower surface.
- Place the electrical contact 2 made of Pd alloy, contact the lower electrode 4 with a flat top surface against the lower surface of the spring terminal material 3, press the upper electrode 4' onto the upper surface of the electrical contact 2, and perform projection welding to make electrical contact. I got a child. When the welding strength of each of the 100 electrical contacts thus obtained was measured, the results shown in the table below were obtained.

[Table] As is clear from the table above, the electrical contact of Conventional Example 1 had low welding strength and was unstable due to large variations in electrical contact, but the electrical contact of Example 1 The strength was high and stable with little variation. In the above-mentioned embodiments of the present invention, the hemispherical protrusion of the lower electrode is provided in Embodiment 1 in order to weld the spring terminal material on the bottom and the electrical contact on the top. When welding is performed with the upper electrode placed on top and the electrical contact placed on the bottom, it is preferable to provide the protrusion on the lower surface of the upper electrode. As detailed above, according to the method of manufacturing an electrical contact of the present invention, the spring terminal material is pressed by the ring-shaped projection of the electrical contact and the protrusion of the welding electrode to slightly curve the spring terminal material. Since projection welding can be carried out by bringing the entire circumference of the ring-shaped projection into equal contact with the spring terminal material, the current flowing during welding is averaged, and the ring-shaped projection is not melted evenly and the electrical contact is not tilted. Furthermore, the hardness of the spring terminal material does not decrease due to thermal fatigue. Therefore, it is possible to obtain a stable electrical contact with high welding strength and little variation.

[Brief explanation of drawings]

Fig. 1a is a sectional view of an electrical contact having a ring-shaped projection on the periphery of the lower surface, Fig. 1b is a bottom view thereof, Fig. 2 is a sectional view showing a conventional method of manufacturing an electrical contact, and Fig. 3 FIG. 1 is a cross-sectional view showing a method of manufacturing an electric contact according to the present invention. DESCRIPTION OF SYMBOLS 1...Ring-shaped projection, 2...Electric contact, 3...Spring terminal material, 4'...Upper electrode, 5...Protrusion, 6...Lower electrode.

Claims (1)

[Claims] 1. In a method of manufacturing an electrical contact in which an electrical contact having a ring-shaped projection is welded to a thin spring terminal material by projection welding, the surface of the spring terminal material opposite to the electrical contact welding surface is Arranging a welding electrode with a hemispherical protrusion on the top surface, and projexion welding by abutting the welding electrode concentrically with the ring-shaped protrusion of the electrical contact through the spring terminal material. A method for manufacturing an electric contact characterized by: