JPS60250891A - Method of manufacturing electrical contacts - Google Patents

Abstract

PURPOSE:To cause a plastic flow in a joining part of a contact, and to join it firmly in a short time when a contact is welded on a base metal by providing grooves of one group on a joint surface of the base metal, performing tin plating, and applying an ultrasonic vibration being parallel to a line of the groove. CONSTITUTION:V-grooves 11 of one group are provided in the direction orthogonal to a longitudinal axis on the joint surface side of a base metal 10, and also tin plating is performed to the base metal 10 by a prescribed thickness. Subsequently, a square piece-shaped contact 9 is placed on the V-grooves 11 of one group of the base metal 10, also the base metal 10 is placed on a knurling division 8 of an anvil 5, and a knurling division 4 of a horn head 2 is pressed against the upper face of the contact 9. Subsequently, an ultrasonic wave is applied to the horn head 2, and the horn head 2 is vibrated by an ultrasonic wave in parallel to the line of the V-group 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] The present invention relates to a method for manufacturing an electric contact, and particularly to a method for joining a contact piece and an alloy by ultrasonic welding.

[Prior art and its problems]

Various methods, such as brazing and resistance welding, are used to join a contact piece and an alloy in electrical contacts such as switches and circuit breakers. In addition to these joining methods, ultrasonic welding has recently been widely used. This method can be expected to have advantages such as being able to join in a short time, eliminating the need for brazing filler metal or flanks, and reducing electrode wear.

On the other hand, there is a problem in that the joining strength of ultrasonic welding is lower than that of brazing.

The reason for this is thought to be that in the case of ultrasonic welding, the joint does not melt to form an alloy, but metal molecules are brought closer to each other and joined by plastic flow.

In order to improve the joint strength in this ultrasonic welding,
The present applicant has previously proposed a method of prolonging the welding time and obtaining high joint strength by intervening soot in the joint during ultrasonic welding of contacts and alloys (Japanese Patent Application No. 158,674/1986).
issue).

According to this method, high bonding strength could be obtained without causing deformation of the contact point, but there was a problem in that it took a long welding time. That is, compared to the case where soot is not involved or the case where metal other than tin is involved, the
It required five times as much welding time.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electric contact which eliminates the above-mentioned problems when applying ultrasonic welding, and which minimizes contact deformation and provides high bonding strength in a short welding period. The purpose of this invention is to provide a method for manufacturing the same.

[Key points of the invention]

In order to achieve the above object, the present invention provides a group of grooves on the joint surface on the base metal side when ultrasonically welding the contact and the alloy, and further provides a groove pattern parallel to the lines of the grooves. The feature is that the bonding is performed by applying ultrasonic vibration.

According to the present invention, by providing a groove in the joint part of the alloy, the joint area becomes smaller compared to a conventional flat joint surface,
Under the same conditions of ultrasonic energy and pressure, it is possible to generate a large amount of heat per unit area, thereby achieving high bonding strength.

[Embodiments of the invention]

Hereinafter, a method for manufacturing an electric contact according to the present invention will be explained using illustrated examples.

1 and 2, reference numeral 1 indicates a horn of an ultrasonic welding machine, and a horn head 2 is fixed to the tip of the horn 1. In FIG. This horn head 2 has four protrusions 3 arranged at equal intervals with a phase angle of 90 degrees, and the tip of each protrusion 3 has a pitch of 0.5 mm and an ff of 0.3 mm.
knurls 4 are formed. The horn head 2 is pressurized in the direction of arrow A during welding, while the horn 1
is caused to reciprocate in a direction B-C orthogonal to this direction.

Further, reference numeral 5 indicates an anvil, and this anvil 5 is placed on a workbench 6, and the upper surface of the anvil 5 has a pinch 0.
The object to be ultrasonically welded by being held between the pawn head 2 and the anvil 5, in which the knurling 8 of 8 mm in diameter and 0.5 mm in depth is formed, is a contact piece 9 and a base metal 10. be. In this embodiment, the contact piece 9 is a silver oxide contact, and the base metal 10 is made of a copper alloy such as brass, and has a plate thickness of 1
mm, and the width is 5 mm.

According to the present invention, on the joint surface side of the base metal 10, a third
As can be seen in the figure, a group of Vmll, 11. ...,,
, 11 are provided in a direction perpendicular to the longitudinal axis. This Vmll, IL..., 11 has a depth of 0.1m
m, pitch 0.5 mm, angle of m 90 degrees,
For example, it is formed in advance by press working or the like.

Further, the base metal 10 is plated with a predetermined thickness. Next, a manufacturing procedure for joining the above-mentioned contact piece 9 to the base metal 10 using an ultrasonic welding machine will be described.

The output of the ultrasonic welding machine used here is 2400W,
The pressing force was 120 kg.

First, a group of V grooves 11 of the base metal 10. IL..., 11
Place the square contact piece 9 on top (see Figure 4), then place the base metal 10 on the knurling 8 of the anvil 5 as shown in Figures 1 and 2, and place the contact piece 9. Push the knurling 4 of the horn head 2 onto the top surface of the piece 9. At this time, what is important is to match the direction of vibration of the horn 1 with the direction of the lines of Vt$11.11, . . . , 11 on the base metal 10.

When the setting is completed in this way, pressurize the horn head 2 with 120 kg, apply ultrasonic vibration to the horn and the horn head 2, and move the horn head 2 to Vmll, 11, .
..., make ultrasonic vibrations parallel to the 11 lines. Then, the material of the contact piece 9 induces plastic flow on the valley side of the grooves 11, 11, .

By the way, ■Groove 11.11. . . . Even if ultrasonic vibration is applied in a direction perpendicular to the 11th line, the same effect cannot be obtained. This means that the metal oxide cannot be removed by tapping and friction, and no bonding occurs.

FIG. 5 shows the results of applying a pressing force of 120 kg between the contact piece 9 and the base metal 10 using a 240H ultrasonic welding machine, and measuring the bonding strength for each welding time. As is clear from this result, when a group of all is provided on the base metal 10, it is possible to maintain the same or higher welding strength in about half the welding time as when no groove is provided. .

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a group of grooves are formed on the joint surface of the alloy, a contact piece is placed on the grooves, and ultrasonic vibration is applied in a direction parallel to the groove lines. Since the joint is made by adding , plastic flow occurs at the joint of the contact piece, resulting in a stronger joint. Furthermore, in order to obtain the same bonding strength, approximately half the welding time is required compared to the conventional example in which no grooves are formed.

[Brief explanation of drawings]

FIG. 1 is a side view showing a contact and an alloy sandwiched between an anvil and a horn head according to the present invention, FIG. 2 is a front view of the same, and FIG. 3 is a perspective view showing the alloy according to the present invention. ,
Figure 4 is a perspective view showing the contact placed on the alloy;
FIG. 5 is a diagram comparing the welding strength of the present invention and the conventional example. ■...Horn, 2...Horn head, 5...Anvil, 9...Contact piece, 10...Alloy, 11...■
Groove Patent Applicant Fuji Electric Seizo Co., Ltd. Paper 1 ri copy 2 book 90 paper 1 play answer! 5th book Azusa■

Claims (1)

[Claims] (1) A group of grooves with a predetermined pitch are formed on the surface of the alloy, a contact piece is placed on this group of grooves, and both are welded between the horn head and anvil of an ultrasonic welding machine. A method for manufacturing an electrical contact, characterized in that the contact piece and the alloy are bonded by clamping the contact piece while pressing and ultrasonically vibrating a horn head in the direction of the lines of the group of grooves. (2. In the method for manufacturing an electric contact according to claim 1, the electric contact is characterized by plating soot on the joint surface including the group of grooves of the alloy before the ultrasonic welding process. Method of producing children.