JPH02129879A - Manufacture of brush contact - Google Patents

Abstract

PURPOSE:To attempt realizing a brush contact having enhanced welding strength, no imperfect contact and inexipensiveness, by drawing and tensionally heat-treating a stainless steel wire plated with a noble metal or a BeCu wire, and subsequently welding the resulting wire to a beltlike base material. CONSTITUTION:The contact in the title can be costlessly formed because a stainless steel wire or a BeCu wire is used as a brush wire rod. The wire is welded via its surface plated with a noble metal to a base material so that the contact has no problem of being oxidized, high welding strength and a stable contact surface. This noble metal plating enables the surface of the wire to be chemically stabilized, thereby cancelling any imperfect contact in making a brush contact. Plating may suffice for use in devices such as a trimmer, an encoder, a potentiometer and the like, which have a comparatively low sliding speed. Drawing of the wire makes any micropore in plating and peelability canceled, and then the wire is linearized by heat treatment while tensioning and strechilng it and also the plating is reformed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing brush contacts used in potentiometers, encoder trimmers, other variable resistors, and the like.

(Prior Art) In recent years, brush contacts have been required to have high contact reliability due to cost reduction, miniaturization, and high density.

Conventionally, brush contacts have been used, which are made by welding a bundle of horizontally aligned stainless steel brush wires, which are cheaper than precious metal brush wires and have excellent spring properties, to a composite material.

(Problem to be Solved by the Invention) By the way, the brush contacts made by welding the wire bundle of the stainless steel brush wire are made of composite material because the Cr in the stainless steel is oxidized by the welding heat during welding of the brush wire and does not blend with the base material. The welding strength was low and unstable, and welding reliability was poor. In addition, stainless steel brush wires are chemically unstable compared to precious metal brush wires, and are more likely to cause poor contact.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a manufacturing method that can produce an inexpensive brush contact point that has high and stable welding strength between a brush wire and a composite material and that does not cause poor contact between the brush wire and the brush wire.

(Means for Solving the Problems) In order to solve the above problems, the method for manufacturing a brush contact of the present invention involves plating a stainless wire or BeCu wire brush wire with a precious metal, then wire drawing, and then applying tension to the brush wire. Next, a large number of brush wire bundles are arranged horizontally to form a brush wire bundle, and then this brush wire bundle is welded to a band-shaped base material, and then the belt-shaped base material and brush wire bundle are assembled to the required length. The brush wire bundle is cut into pieces, and a contact portion of a desired shape is formed at the tip of the brush wire bundle.

(Function) As described above, the method for manufacturing the brush contact of the present invention uses stainless steel wire or BeCu wire as the brush wire, so it is inexpensive, and since it is plated with a precious metal, the chemically unstable surface is improved. This eliminates poor contact of the brush contacts.

Moreover, when using trimmers, encoders, potentiometers, etc., the number of sliding movements is limited to several to several hundred times, so plating is sufficient. Furthermore, the fine pores and peelability of plating are eliminated because wire drawing is performed after plating. Furthermore, since the brush wire is then subjected to heat treatment by applying tension, the brush wire is straightened and straightened, and the plating is modified. Since this brush wire is welded to the composite material through the plated surface, there is no problem of oxidation, and the welding strength is high and stable.

(Example) An example of the method for manufacturing a brush contact of the present invention will be described as follows.
As shown in FIG. 1, a brush wire 1 made of 5US304 with a wire diameter of 100 μm is coated with 3 μm of Au plate 2, and then drawn through a die D as shown in FIG.
μm brush wire 1', then heat-treated at 800°C under a tension of 50 g, and then 14 brush wires 1' are arranged horizontally as shown in FIG. 3 to form a brush wire bundle 3. Then, as shown in Fig. 4, a depth of 50 μm and a width of 95
Width 10+nm, outer diameter 100 with groove 4 of 0 μm on the outer periphery
The upper roll electrode 5 of mm is rotated at a rotational speed of 3.2 rprII, and the 14 brush wire bundles 3 are wound around the groove 4 on its outer periphery from above and transferred in alignment, and the upper roll electrode 5 and the upper roll electrode 5 are and a lower roll electrode 6 with the same dimensions and no groove on the outer periphery, with a width of 10 mm and a thickness of 0.2 mm.
A band-like base material 9 with window holes made of phosphor bronze and equipped with a rod 8 having a projection 7 of 50 μm in height at a pitch of 5 mm at +nm is transferred, and the brush wire bundle 3 is sequentially applied to the rod 8 of this belt-like base material 9. Projection welded.

The beam 8 of the band-shaped base material 9 to which this brush wire bundle 3 was projection welded was then cut at both left and right ends as shown in FIG.
It is cut at the position indicated by the dashed line n, and then the tip of the brush wire bundle 3 is formed and processed to form a 0.5+nm layer on the lower side as shown in FIG.
A semicircular contact portion 10 of radius R was formed to obtain a brush contact 11.

On the other hand, to explain the conventional example, a wire bundle of 14 brush wires made of SUS 304 with a wire diameter of 100 μm, which is the same as in the example without Au plating, without wire drawing, and without heat treatment, was used in the same band-shaped base material with window holes as in the example. A brush contact point was obtained by projection welding to the beam of the beam, cutting both ends of the beam, cutting the brush wire bundle, and forming the tip of the brush wire bundle to form the same contact part as in the example. .

The welding strength of the brush wire was measured for 100 brush contacts of the example and conventional example thus obtained, and the results shown in the table below were obtained.

As is clear from the above table, it can be seen that the brush contacts of the examples have higher welding strength of the brush wire and are stable with less variation than the brush contacts of the conventional examples.

Incidentally, in the above embodiment, the brush wire bundle 3 is sequentially welded to the machine 8 of the band-shaped base material 9 with window holes, but as shown in FIG. The brush wire bundle 3 may be fed in a direction perpendicular to the feeding of the brush wire bundle 3, and the upper and lower electrodes 5', 6' may be welded at orthogonal positions between the brush wire bundle 3 and the strip base material 9'. Thereafter, each of the brush wire bundles 3 is cut to a required length at the positions indicated by the chain lines, and as shown in FIG. is obtained.

(Effects of the Invention) As can be seen from the above explanation, according to the method for manufacturing brush contacts of the present invention, the welding strength between the brush wire and the composite material is high and stable, and the surface of the brush wire is chemically stable. This has the effect that it is possible to obtain an inexpensive brush contact point that does not cause poor contact even when the brush is used.

[Brief explanation of the drawing]

1 to 6 are diagrams showing one embodiment of the method for manufacturing a brush contact of the present invention, and FIGS. 7a and 7b are diagrams showing another embodiment. Applicant Tanaka Kikinzoku Kogyo Co., Ltd.

Claims (1)

[Claims] 1. Precious metal plating is applied to stainless steel wire or BeCu wire brush wire, then wire drawing is applied, heat treatment is performed under tension, and then a large number of brush wires are arranged horizontally to form a brush wire bundle. A brush contact characterized in that the bundle is welded to a band-shaped base material, the band-shaped base material and the brush wire bundle are then cut to a required length, and a contact portion of a desired shape is formed at the tip of the brush wire bundle. manufacturing method.