JPS61185820A - Manufacture of 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 Field of the Invention The present invention relates to a method of manufacturing contacts for electrical equipment such as electromagnetic relays.

<Prior art and its problems> Conventionally, in electrical equipment such as electromagnetic relays, electric contacts such as a movable contact fixed to a movable contact piece and a fixed contact fixed to a fixed contact piece are used as shown in Fig. 11. Single contact base made of silver metal made of silver or silver alloy 10
A method is known in which a precious metal layer 11 of a gold thread metal made of gold or a gold alloy is formed on the contact surface of the single contact base 10 and the top surface 10A of the contact base 10 by plating or cladding.

Such an electrical contact 12 is used by being fixed on a contact piece 13, such as a movable contact piece or a fixed contact piece, as shown in FIG. 12, for example.

Since the contact base unit 10 is made of silver-based metal, it is greatly affected by corrosive atmospheres, and in particular, in sulfidic atmospheres, sulfides (AHS) are generated and the contact resistance is increased. increase properly.

In addition, in order to prevent the negative effects from the corrosive atmosphere, a noble metal layer 11 made of a gold-based metal, which has better corrosion resistance than silver-based metals, is placed on the top surface 10A of the single contact base 10. The contact stability is maintained even in corrosive atmospheres.

However, in practice, sulfides generated in the single contact base 10 leached to the peripheral edge of the noble metal layer 11, forming a sulfide film on the peripheral edge, resulting in an increased contact resistance.

<Purpose of the Invention> This invention was made to solve the above-mentioned conventional problem, and the sulfide generated in the contact base itself leaks to the periphery of the noble metal layer, forming a sulfide film on the periphery. Even if formed,
An object of the present invention is to provide a method for manufacturing an electrical contact that can ensure contact stability without increasing contact resistance.

<Configuration and Effects of the Invention> The electrical contact according to the present invention is made of a silver-based metal such as silver or a silver alloy. A gold-based noble metal layer is formed on the top surface of the base, and the stepped part is covered with a noble metal skirt extending from the noble metal layer, and the contacts are arranged at predetermined intervals in the longitudinal direction of the contact base. A trough that crosses the base is formed by press working from the noble metal layer side, that is, the top surface side of the contact base, and the center of this trough is cut in the width direction to divide it into a plurality of single contact bases. , is characterized in that stepped portions coated with the noble metal layer are formed on the front and rear edges of the top surface of each single contact base.

Therefore, according to the electrical contact manufactured according to the present invention, at the peripheral edge of the top surface of the single contact base.

Because the step part covered with a precious metal layer is formed,
Even if the sulfide produced by the contact base itself leaches out and forms a sulfide film on the precious metal layer covering the step-down part, the above will not reach the part covering the top surface of the contact base alone. Since no sulfides are leached out, an increase in contact resistance is prevented.

<Explanation of Examples> Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing the manufacturing process of the electrical contact according to the present invention, and FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. A detailed explanation thereof will be omitted by attaching a reference numeral. In the figure, IOX is a strip-shaped contact base made of silver metal such as silver or silver alloy, and has slanted stepped portions 1 on both side edges of its top surface 10A.
0a$10& is formed.

A noble metal layer 11 made of a gold thread noble metal such as gold or gold alloy is formed on the flat top surface 10A of the contact base 10X, and a noble metal skirt extends from the noble metal layer 11 with the stepped portion 106° 10a. Cover with portion 11a. The noble metal layer 11 and the noble metal skirt portion 11& are formed by plating or cuturad processing.

Next, as shown in FIG. 3, valleys 14 are formed that extend across the contact base 10X at predetermined intervals in the longitudinal direction of the contact base 10X. These troughs 14 form the noble metal layer 11991. as shown in FIG. In other words, the top surface 10A of the contact base
It is formed by a punch 15 of a press that is pushed down from the side.

Subsequently, as shown in FIG. 5, the center of the trough 14 is cut in the width direction by a cutter 16 of a cutting mechanism (a press machine may be used), and a plurality of contact points are cut as shown in FIG. 6 and FIG. 7. The top surface 1 of each contact base unit 10 is divided into base units 10.
Step-like stepped portions 10b, 10b covered with the noble metal layer 11 are formed at the front and rear edges of 0A.

The electrical contact 12 manufactured in this way is fixed onto a contact piece 13 such as a movable contact piece or a fixed contact piece by welding, caulking, etc. as shown in FIG. Both side edges and front and rear edges of 10A, that is,
The peripheral edge of the single contact base 10 is covered with a noble metal layer 11 and a noble metal skirt portion 11A, with step-down portions 10B and 1Q.
a, 10b, and 10b are formed, the sulfide generated in the contact base unit 10 leaches out, and the stepped part 1 (1
, 10B, 10b, 10b, and even if a sulfide film is formed on the noble metal skirt portion 11&, it will not reach the noble metal layer 11 covering the flat top surface 10A of the contact base unit 10. Since the sulfide does not leach out, an increase in contact resistance is prevented.

In the above embodiment, an example will be described in which a trough 14 that crosses the strip-shaped contact base 10Xt is formed by a punch 15 of a press machine, and then the center of this trough 14 is cut by a cutter 16 of a cutting mechanism. However, the present invention is not limited to the above embodiment, and as shown in FIG. 9, there are pressing surfaces 17 & on both sides.

First, the contact base 10X is cut in the width direction using the cutter 17 with the cutter 17a formed in an overhanging manner.
．． 17& may be pressed against the front and rear edges of the top surface 10A to form step-like stepped portions 10b, 10b covered with the noble metal layer 11.

Further, as shown in FIG. 10, an inclined pressing surface 188.
18 & is formed to extend and cut in the width direction of the contact base 10 The edges also have slanted stepped portions 1 (slanted stepped portions 10b, 1, which are the same as 1, 10a) on both side edges.
0b, and the electrical contact 12 in which the stepped portions 10b, 10b are covered with the noble metal layer 11 can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the manufacturing process of the t9C contact according to the present invention, FIG. 2 is a sectional view taken along line 2-2 in FIG. 1,
@Figure 3 is a perspective view of the contact base with valleys formed, the 4th figure is
FIG. 5 is a side view showing an example of a method for forming valleys, FIG. 5 is a side view showing an example of cutting, FIG. 6 is a perspective view showing an example of an electrical contact manufactured by the present invention, and FIG. 6 is a sectional view taken along the line 7-7 in FIG. 6, FIG. 8 is a perspective view showing the support fixed to the contact piece, FIG. 9 is a side view showing a modified example of the cutter used in the present invention, and FIG. FIG. 11 is a side view showing still another example, and FIG. 11 is a perspective view of a conventional electrical contact.
FIG. 2 is a perspective view showing a state in which the contact piece is fixed. 10...Contact base ugly body, IOA...Top surface, IOX...
...Contact base, 10 &, 10b... Stepped part, 11.
...Precious metal layer, 11&...Precious metal skirt part, 14.
...Tanibe. Figure 1 Figure 4 Figure 6 Figure 10b Single drop part Figure 8

Claims (1)

[Claims] (1) A gold-based noble metal layer is formed on the top surface of a strip-shaped contact base made of silver-based metal and has stepped portions formed on both edges of the top surface, and the stepped portions are separated from the noble metal layer. The contact base is covered with an extended noble metal skirt portion, and a trough is formed from the noble metal layer side at a predetermined interval in the longitudinal direction of the contact base and crosses the contact base. A method for manufacturing an electrical contact, which comprises cutting the contact base into a plurality of single contact bases, and forming stepped portions coated with the noble metal layer on the front and rear edges of the top surface of each single contact base.