JPS5893568A - Spot welding method for contact - Google Patents

Abstract

PURPOSE:To perform spot welding of a contact without damaging a noble metal part, by welding the entire reverse surface of a metallic plate as the base plate of a noble metal chip to a terminal plate through fused alloy without bringing an electrode for the spot welding into contact with the chip. CONSTITUTION:A chip 1 made of noble metal such as platinum which has less electric resistance and a low melting point is made of copper, etc., which has an greater electric resistance value and a higher melting point than the chip 1, and then stuck to the center top surface of a head 2 wider than the chip 1. Then, fused alloy 4 of silver solder, etc., is cold-jointed to a recessed part 3 provided to the reverse surface of the head 2, which is opposed to and over a terminal plate 5 with space left. Then, electrodes S for spot welding are brought into contact with both shoulder parts 2a of the head 2 and a current is flowed as shown by an arrow from both shoulder parts 2a to the terminal plate 5 through fused alloy 4. As a result, the alloy 4 is melted to fill space T while the space T is narrowed down lastly. Therefore, neither electrode S abuts on the chip 1, which is never damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application) The present invention relates to a method of spot welding contacts using precious metals such as platinum, gold, silver, etc. as contact materials and spot welding them.

(Problems with the Prior Art) Generally, it is desirable to perform spot welding without damaging the surface of the contact.

Therefore, a method was developed in which the contact is divided into two parts: a small chip-shaped precious metal part and a large current-carrying part, and the two parts are joined together, and spot electrodes are applied to both shoulders of the wide current-carrying part for welding.

By the way, in the above case, the electrode presses on both shoulders, so only the periphery is welded, and the contact at the center is insufficient, and the heat from the contact is not quickly transferred to the terminal plate, resulting in poor heat dissipation. That's the fault.

(Objective) The present invention has been made in view of the above points, namely, the spot welding electrode does not touch the noble metal chip, and the lower surface of the metal plate that is the plywood of this chip is entirely covered with terminals. It is designed to be welded to a plate via a molten alloy, so that the noble metal part will not be damaged, and the purpose is to improve heat dissipation.

(Example) The present invention will be explained based on the drawings as an example. Fig. 1 shows a material made of a material having a small electric resistance value J and a low melting point, such as platinum, gold, silver, etc. A chip 1 made of noble metal and a material having a higher electrical resistance than the chip 1 and a higher melting point, such as steel, nickel alloy, etc.,
Moreover, the process of molding the head 2, which has a wider area than the chip 1, is shown. That is, a band-shaped noble metal chip material Both shoulder portions 2a of No. 2 will be exposed. Further, in the above process, a molten alloy material 2 such as silver solder or tin is similarly cold-bonded and fitted into the recess 3 formed on the lower surface of one head material Y.

After cutting as shown in FIG. 1, the molten alloy 4 is placed on the upper surface of the terminal plate 5 as shown in FIG. 2(A). At this time, a space T exists between the lower surface of the metal spatula 2 and the upper surface of the terminal plate 5.

Therefore, when the spot welding electrode S is applied to the exposed shoulders 2a, a current flows as shown by the arrow. That is, the molten alloy 4 reaches the terminal plate 5 from both shoulders 2a of the metal head 2, and does not directly reach the terminal plate 5 from the shoulders 2a. This molten alloy 4 is melted because it has a lower electrical resistance value and a lower melting point than 2. This is shown in (b).

Finally, as shown in FIG. 3, the space T becomes narrower and is filled with the molten alloy 4.

Therefore, the spot welding electrode S does not hit the noble metal tip 1, so that it will not be damaged.

(Effects) As described above, the present invention fixes the noble metal chip 1 having a small electrical resistance value and a low melting point on the top surface of a metal head,
The molten alloy 4 was fitted and protruded from the lower surface of the metal head 2, and the molten alloy 4 was placed on the terminal plate 5, and spot welding electrodes S were applied to both shoulders 2a of the metal head 2. The lifting of the center part due to the fact that the noble metal tip 1 is not damaged by the welding electrode S and the electrode S does not hit the center of the noble metal tip L is due to the molten alloy 4.
This can be prevented by the melting of the metal, which has the effect that there is no hindrance to heat dissipation.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1I is a diagram of the molding process of each material, FIGS. 2A and 2B are diagrams of the welding process, and FIG. 3 is a diagram of the finished product. l...Precious metal chip, 2...Metal head, 2a
... both shoulders, 3 ... recess, 4 ... molten alloy, 5.
・Terminal board. Patent applicant Matsushita Electric Works Co., Ltd. Patent attorney Toshikuro Takemoto (and 2 others) 5- 1st! II X (a) Figure 3 5

Claims (1)

[Claims] A noble metal chip with a low electrical resistance value and a low melting point is fixed to the central upper surface of a metal head with a larger electrical resistance value and a higher melting point than the chip, and which has a wider area. A molten alloy such as silver solder or tin is installed in a recess formed on the lower surface so as to protrude from the lower surface, and the protruding molten alloy is placed on the surface of the terminal plate, and the metal head is placed between the terminal plate and the space. In this state, spot welding electrodes are applied to the left and right sides of the chip and both shoulders of the head and the current is applied from both shoulders through the head and molten alloy to the terminal plate. Due to the melting of the molten alloy, the space between the head and the terminal plate is narrowed, and the molten alloy flows directly from both shoulders to the terminal plate, filling the space between the head and the terminal plate. A contact spot welding method featuring: