JPH0122692B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing contacts such as switches,
In particular, the purpose is to save materials without sacrificing its electrical performance.

Generally, the contacts of switches, etc., tend to form oxide films or sulfide films due to environmental changes, changes over time, etc., which can easily cause contact failure. are doing. For example, there is a method of gold plating the entire surface of the contact terminal including the contact portion, but since this requires a large amount of gold, a structure as shown in FIG. 1 is generally used. That is, a hole 12 is drilled at the contact point of a phosphor bronze base material 11, and a so-called gold clad material, which is made by laminating gold with a thickness of 1 micron to several microns by cold rolling, is pressed onto the phosphor bronze with a width of about 2 mm. This is a method of filling the hole 12 by processing (this is called a contact point), and the amount of gold used is considerably reduced, but even with this method, the material that is discarded by pressing the gold clad material cannot be ignored. On top of that, there was a drawback that costs could not be reduced.

Generally speaking, there are two ways to reduce costs: using fewer materials and using lower-priced materials, but switches as electronic components must be made of materials that can be soldered, and contacts must be made of corrosion-resistant materials. The material needs to have properties such as durability and abrasion resistance, and it is difficult to find a material that can satisfy these properties at a low price.

The present invention uses low-cost materials such as iron, stainless steel, or permalloy that are available to us, and only the surface of the contact is made of gold, so that it can be used as a low-cost contact without impairing the performance of the contact. can be formed.

Hereinafter, the embodiment will be described in detail with reference to the drawings. As shown in FIG. It is formed by performing the following processing on a contact strip L which is nickel-plated and then tin-plated 2.

As shown in FIG. 2a, an ultrafine gold wire 4 having a wire diameter of about 20 to 50 μm is inserted into a capillary tube 3 made of molybdenum or the like. The diameter of the hole in the tube 3 is about 5 microns larger than the wire diameter of the gold wire 4, and it can be pulled out by pulling the gold wire 4 with tweezers or the like. Next, the gold wire 4 is melted by applying a hydrogen flame 9 from a torch lamp to the second
Fine gold particles 5 are made as shown in Figure b. The size of the fine particles 5 can be adjusted by adjusting the size of the flame. Next, the state in which the capillary tube 3 is pushed down and pressed onto the surface of the sparrow 2 is shown in FIG. Capillary tube 3 is 200℃
The base material 1 is heated to about 300°C. Since the melting point of tin is 232°C, tin melts and fuses with fine gold particles 5 to form an alloy, whose composition becomes 35% gold and 65% tin at 300°C.
When the tube 3 is pulled upward, the gold wire 4 remains as it is, and only the tube 3 is lifted upward, as shown in FIG. 2d.

At this time, when tin oxidizes, the melting point increases,
In order to prevent this from forming into an alloy, nitrogen gas is introduced during pulling. Also,
When the gold wire 4 is tightened and clamped by the tube 3 while the tube 3 is being pulled up, the gold wire 4 is cut at the top of the fine grains 5, resulting in a shape as shown in FIG. 2e. Next, as shown in FIG. 2 f, remove the capillary tube 3, set a press 6 in its place, and heat the press 6 to about 200°C,
The fine gold particles 5 are hot-pressed to make them flat, and then pressed between the upper and lower sides with double presses 7, 7 shaped as shown in FIG. Part 8 is formed.

The present invention has the above-mentioned structure, and there is no waste of gold material, it is used 100% effectively, the amount used is very small, and the cost of the contact part is 10% compared to the conventional eye contact. /4 to 1/6 is enough. Further, there is no need to select a special material for the base material of the contact terminal, and a low-cost material such as iron may be used. Furthermore, the manufacturing process is simple, and there are many advantages in manufacturing contact terminals, such as the fact that the previous and subsequent steps, that is, press working of the contact terminal and press working of the contact part, can be performed continuously.

Furthermore, by forming a nickel plating film on a base material such as iron, there is an effect of preventing the diffusion of gold into the base material and increasing the adhesive strength with the tin-gold alloy.

[Brief explanation of drawings]

Figure 1 is a plan view of a conventional contact terminal, Figure 2 a~
g is an explanatory diagram of the manufacturing process of the contact terminal according to the present invention. DESCRIPTION OF SYMBOLS 1... Base material, 2... Tin plating film, 4... Gold ultrafine wire, 5... Gold fine particles, 6, 7... Press, 8... Gold contact part, L... Contact strip.

Claims (1)

[Claims] 1 After forming a contact strip by applying a tin plating film to a metal base material such as iron through a nickel base plating, this contact strip is heated, and fine gold particles formed by heating an ultra-fine gold wire are formed into a contact strip. A method for manufacturing a contact, comprising: alloying the tin plating film with fine gold particles by pressure bonding to the surface of the metal, and then rolling this alloy part by press working to form a contact part.