JPS5880220A - Method of bonding electric contact - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a method for joining electrical contacts.

Conventionally, when manufacturing this type of electrical contact that requires drop-off resistance and wear resistance, brazing is usually used to join the contact (1) and the base (3) as shown in Figure 1. was. That is, first, a silver lining layer (illustration) is formed on the bonding surface of the contact (1), and then a brazing metal,
When the flux is inserted and the brazing work is performed, the brazing phenomenon progresses between the silver lining layer (2) and the pedestal (3), and the periphery of the contact point (1) has a bond with the pedestal (3). A fillet (4) is formed in between, but at the same time, a wax phase part (
6) Many large voids, that is, large cavities (6), were likely to occur within the contact point (1) and the pedestal (3) were extremely unstable.

In order to deal with this problem and to omit materials such as brazing filler metal and flux, a spot welding method as shown in FIG. 2 has conventionally been used. In other words, a contact (1) with a silver lining layer (2) and a pedestal made of prepared alloy (
3) is held between the upper electrode (7), which is the first electrode, and the lower electrode (8), which is the second electrode, at a predetermined pressure from both sides, and a liquid supply nozzle (3) is placed around the contact point (3). 9) is a method of applying electricity after or while dropping a liquid such as water. In other words, by shielding the area around the joint with liquid QQ such as water, a uniformly shaped lyret (4) is formed around the periphery of the contact (1), and a large cavity (6) is generated at the joint. I tried not to do that. That is, the backing silver layer (2
) and a part of the pedestal (3) melt and elute to the outside, the surfaces of the contact (1) and pedestal (3) in a high temperature state are usually exposed to liquid aQ, such as water, that has been dropped during oxidation. In other words, since the water vapor shields the surrounding area and lowers the oxygen partial pressure, the rate of oxidation progresses is extremely slow, and the surface cleaning action is overcome, and the eluted metal flows to the contact point (1) and the pedestal (
It is interpreted that it blends well with the surface of 3) and forms a uniform fillet (4). Furthermore, since no flux is used in this method, no large cavity (6) is generated at the joint.

However, in the conventional spot welding method in which a liquid (Ql) such as water is dripped, as shown in Fig. 2, depending on the amount of liquid dripping, the dripping condition, or the surface condition of the contact (1) or the pedestal (3), , liquid (Ql) such as water may not be uniformly shielded around the joint.

As a result, as shown in FIG. 8, the fillet (4) was not formed at the peripheral edge of the contact (1) on the side where the shielding was not complete, and the eluted metal sometimes protruded as a lump. This separation (b) causes a significant deterioration in the fall-off resistance and life of the contact (1).

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional method, and it is possible to obtain a good joint by spraying a liquid αQ such as water in the form of a mist. An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a schematic diagram showing an embodiment of the method for joining electrical contacts according to the present invention. In the drawings, the same parts as in FIGS. 1 to 8 are designated by the same reference numerals. That is, in the present invention, after or while spraying a mist liquid such as water around the parts to be joined using the sprayer (2), the upper and lower electrodes (
7) , (8) energized between contact (1) and pedestal (3)
It is used to join. According to the method of this invention, the area around the parts to be joined is already completely shielded with a mist of liquid at the time of starting energization, so it is better than the conventional method of simply dropping liquid αQ such as water. Also, the eluted metal blends well into the contact point (1) and the pedestal (3), and there is no occurrence of cracks (b) as shown in Fig. 8 (and a uniform fillet as shown in Fig. 6). A joint having (4) is obtained.

In addition, in the above example, a case was explained in which water was used as the atomized liquid (to) sprayed by a sprayer.
Similar effects can be obtained when using alcohol or a mixture of water and alcohol.

As described above, according to Jin's invention, there is no formation of flakes on the periphery of the contact and a uniform fillet is created stably without using a box, so there is no large cavity in the joint, and the joint strength is It has various effects such as improving the drop-off resistance and wear resistance required for high-performance contacts.

[Brief explanation of drawings]

Fig. 1 is a side sectional view showing electrical contacts joined by brazing, Fig. 2 is a schematic diagram showing a joining method by conventional spot welding, and Fig. 8 shows electrical contacts joined by conventional spot welding. 4 is a schematic diagram showing an embodiment of the method of joining electrical contacts according to the present invention, and FIG. 6 is a sectional side view showing the electrical contacts joined by the joining method of the present invention. In the figures, the same parts in each figure are given the same symbols, (1) is the contact, (2) is the lining silver layer, (3) is the pedestal,
(7) is the upper electrode, (8) is the lower electrode, the ring is the sprayer, (
) is a mist-like liquid. Representative Patent Attorney Shin Kuzuno - Figure 1 Figure 2 Figure 4

Claims (3)

[Claims] (1) The contact points and the pedestal to be joined to each other are connected to the first. While holding the liquid at a predetermined pressure between the second electrodes or spraying the liquid in the form of a mist around the joint between the contact point and the pedestal, or after spraying the liquid, the first. A method for joining electrical contacts, characterized in that electricity is passed between second electrodes. (2) The method for joining electrical contacts according to claim (1), wherein the liquid is water, alcohol, or a mixture of water and alcohol. (3) A method for joining electrical contacts according to claim (1) or (2), wherein a surface of the contact to be joined is coated with a silver layer.