JPH0119210B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing electrical contacts, and more particularly to a method of manufacturing composite electrical contacts. Conventionally, for example, in order to make a button-type composite electrical contact, a contact wire 1 and a base wire 2 shown in FIG.
were cut into predetermined lengths as shown in Figure 1b,
Next, the contact material 1' and the base material 2' obtained by cutting are resistance welded as shown in FIG. It was press-molded into a button-type composite electrical contact 5. However, in the method of manufacturing such a button-type composite electrical contact, generally an Ag alloy with high Vickers hardness is used for the contact wire 1, and a Cu alloy with low Vickers hardness is used for the base wire 2.
A composite material 3 made by resistance welding the contact material 1' and base material 2' obtained by cutting these materials is press-formed using upper and lower punches 6 and 7 as shown in FIG. A stress that tends to spread outward acts on the material 2', causing it to plastically deform as shown by the arrow.
Therefore, as shown in FIGS. 3a and 3b, a button-type composite electrical contact 5 with a ring projection 4 is formed in which the height of the bonding surface between the contact material 1' and the base material 2' is uneven, so that it is difficult to use as a contact. During use, wear quickly reaches the level indicated by the dotted line, and when wear progresses to this level, the base material 2' is exposed, resulting in unstable contact and poor continuity. Ta. The present invention has been made to solve these problems, and provides an electrical contact that can make the height of the joint surface uniform and have high and stable joint strength regardless of the hardness of the contact material and the base material. The purpose of this invention is to provide a method for manufacturing. The method for manufacturing an electrical contact of the present invention involves cutting a contact wire material and a base wire material into predetermined lengths, and then cutting the contact wire material and base material into predetermined lengths, whichever has the lower hardness. One end surface is formed into a conical surface,
Next, the harder one of the base material and the contact material cut into a predetermined length is resistance welded to this conical surface, and the composite material obtained by resistance welding is then shaped into the desired shape. It is characterized by being press-formed. Note that the apex angle of the conical surface is preferably 90 to 140 degrees. If it is over 140 degrees, it will be difficult to make the height of the bonding surface between the contact material and base material uniform due to the difference in hardness, and if it is less than 90 degrees, the tension near the apex angle will tend to be thinner than the outer periphery. It is. An example of this will be explained below with reference to the drawings.The contact wire 1 and the base wire 2 shown in FIG.
As shown in Fig. 4c, each of the base materials 2' is cut to a predetermined length, and then the upper surface of the base material 2' with low hardness obtained by cutting to a predetermined length is formed to form the apex angle of the conical surface as shown in Fig. 4c. teeth
A conical surface 2'a of 90 to 140 degrees is formed, and then the conical surface 2'a of this base material 2' is cut to a predetermined length as shown in FIG. 4d. The contact material 1' having a high height is resistance welded, and the resistance welded composite material 3' is then pressure-formed into a button-type composite electrical contact 5 with a ring projection 4, for example, as shown in FIG. 4e. . Note that the composite material 3' may be pressure molded into other desired contact shapes such as a rivet type composite electrical contact. As described above, the method for manufacturing an electrical contact of the present invention involves forming the upper surface of the base material 2' with low hardness into a conical surface, and resistance welding the contact material 1' with high hardness onto this conical surface, as shown in FIG. 4d. A composite material 3' as shown in FIG. The portion is gradually crushed and stress is applied to the outer circumferential portion, but since this outer circumferential portion is not in contact with the contact material 1', it is plastically deformed upward as shown by the arrow. Therefore, a button-type composite electrical contact 5 with a ring projection 4 as shown in FIG. 6, for example, can be obtained in which the height of the bonding surface between the contact material 1' and the base material 2' is substantially uniform. When this button-type composite electric contact 5 is actually used as a contact, the wear up to the base material 2' will be reduced compared to the conventional button-type composite electric contact 5 with ring projection 4 as shown in FIGS. 3a and 3b. Since it is slower than that, the contact life is longer. Next, in order to clarify the effects of the method of manufacturing an electrical contact of the present invention, specific examples and conventional examples thereof will be described. [Example] Ag-1.45 mm in diameter as shown in Figure 4a.
The contact wire 1 made of Cu2w/o-Cd2w/o-Ni0.5w/o and the base wire 2 made of Cu-Ni4.5w/o with a diameter of 1.45 mm are each 1.2 as shown in Fig. 4b.
The upper surface of the base material 2' obtained by cutting the base material 2' to a length of 1.2 mm is formed into a conical surface 2'a with an apex angle of 120 degrees as shown in Fig. 4c, and then On the conical surface 2'a of this base material 2', as shown in Fig. 4d,
The contact material 1' obtained by cutting into a length of 1.2 mm is resistance welded, and then the composite material 3' obtained by resistance welding is pressure-formed to have an outer diameter as shown in FIG. 4e, for example. 1.5mm,
Inner diameter 1.1mm, height 0.2mm ring projection 4 on the bottom diameter 3.0mm, height including ring projection 4 0.8mm, height of contact material 1'
A 0.3 mm button-type composite electrical contact 5 was obtained. [Conventional example] Ag− with a diameter of 1.45 mm as shown in Figure 1a.
The contact wire 1 made of Cu2w/o-Cd2w/o-Ni0.5w/o and the base material 2 made of Cu-Ni4.5w/o with a diameter of 1.45mm are each 1.2mm in diameter as shown in Fig. 1b.
The contact material 1' and the base material 2' thus obtained are then resistance welded as shown in Fig. 1c, and the composite material 3 obtained by this resistance welding is press-formed. For example, the outer diameter is 1.5 mm, as shown in Figure 1 d.
Diameter 3.0 mm, height including ring projection 4 0.8 mm, height of contact material 1' with inner diameter 1.1 mm, height 0.2 mm ring projection 4 on the bottom
A 0.3 mm button-type composite electrical contact 5 was obtained. When the tension thickness of the contact material 1' was measured for each of 100 of the button-type composite electrical contacts 5 with ring projection 4 of the example and the conventional example manufactured in this way, the results shown in the table below were obtained. Ta.

[Table] As is clear from the table above, the button type composite electric contact 5 of the embodiment is different from the button type composite electric contact 5 of the conventional example.
In comparison, it can be seen that the thickness of the contact material 1' is stable with very little variation. As detailed above, according to the method for manufacturing an electrical contact of the present invention, it is possible to obtain an electrical contact in which the height of the bonding surface between the contact material and the base material is substantially uniform. Furthermore, according to the method of manufacturing an electrical contact of the present invention, the harder one of the contact material and the base material is projection welded to the top of the upper conical surface of the lower hard one. It has excellent effects such as high bonding strength with the base material and the ability to obtain stable electrical contacts.

[Brief explanation of drawings]

Figures 1a to d are cross-sectional views showing the steps of a conventional button-type composite electrical contact manufacturing method, and Figure 2 is pressure-forming of a composite material made by bonding a contact material and a base material into a button-type composite electrical contact. FIGS. 3a and 3b are cross-sectional views showing the defective state of button-type composite electrical contacts obtained by conventional manufacturing methods, and FIGS. 4a to 4e are sectional views showing the state of plastic deformation when Figure 5 shows the state of plastic deformation during pressure molding of a composite material obtained by resistance welding the contact material and base material in the manufacturing method of the present invention. FIG. 6 is an enlarged sectional view of a button-type composite electrical contact obtained by the manufacturing method of the present invention. 1... Contact wire rod, 1'... Contact material, 2... Base wire rod, 2'... Base material, 2'a... Conical surface,
3'...Composite material, 4...Ring projection,
5...Button-type composite electrical contact, 6...Upper punch, 7...Lower punch.

Claims (1)

[Claims] 1 Cut the contact wire material and the base wire material to a predetermined length, and then mold one end surface of the lower hardness of the contact material and base material obtained by cutting the contact wire material to a predetermined length to form a conical surface. Next, on this conical surface, the harder one of the base material and contact material obtained by cutting to a predetermined length is resistance welded, and then the composite material obtained by this resistance welding is shaped into the desired shape. 1. A method for manufacturing an electrical contact, the method comprising pressure forming the electrical contact.