JPH0255912B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a sliding contact.

Conventionally, clad materials clad with noble metal materials have been widely used for electrical and electronic components such as connectors and brushes. This is because noble metal materials do not oxidize in the air and are stable and have low contact resistance, making them suitable for contacts for electrical devices that require reliability. This type of cladding material has been manufactured by first joining a precious metal material to a spring material by welding, brazing, thermocompression bonding, etc., then rolling it, and, if necessary, subjecting it to precipitation hardening treatment. The clad material produced in this way has a noble metal layer with a thickness of about several tens of microns.
When the thickness of the precious metal is as thin as several microns, it is manufactured by precious metal plating.

However, according to the cladding method among conventional manufacturing methods, the surface layer of the cladding material was in a soft state because the noble metal has excellent malleability. Therefore, when used as a connector material or brush material, it was necessary to reduce the contact pressure to prevent loss of precious metal materials due to mechanical wear. Therefore, for example, when attempting to use it as a brush material for a multi-function motor with large rotational fluctuations, it may not work due to poor contact when the rotational speed is high due to variations in contact pressure.

On the other hand, the plating method has the disadvantage that gas is involved in the plating layer when the particles are deposited, so even when a weak current is applied, the plating layer is subject to rapid wear.

The present invention has been made in view of the above-mentioned drawbacks, and focuses on the fact that when the plating layer is as thin as 10 microns or less, the surface condition of the underlying metal appears on the plating surface layer as well, and is adapted to the cladding material. The purpose of this invention is to provide a sliding contact with high hardness on the surface of precious metal and low wear.

The present invention involves bonding a noble metal material with excellent malleability to a chemically pretreated precipitation hardening spring material, rolling this clad material to a thickness of 10 microns or less, and then precipitation hardening the spring material. This method of manufacturing a sliding contact is characterized in that a hardened layer is formed on the surface of the precious metal.

In the present invention, the reason why the precipitation hardening type spring material is chemically pretreated in advance is to expose the chemically pretreated surface to the contact surface layer of the noble metal material when it is used as a sliding contact. This chemically pretreated surface remains intact even when precious metal materials are joined by welding or heat pressure welding. In addition, the precious metal layer
The reason why we perform precipitation hardening after reducing the thickness to 10 microns or less is to precipitation harden the spring material and increase the hardness of the surface of the precipitation hardened layer to the surface of the noble metal layer of 10 microns or less. . By increasing the hardness, mechanical wear can be prevented even if the contact pressure is weakened, and electrical consumption can also be suppressed.

Examples and conventional examples will be described below.

〔Example〕

A 2% beryllium-copper alloy plate material having a thickness of 1 mm and a width of 20 mm was immersed in dilute hydrochloric acid to undergo chemical pretreatment. Thereafter, a 30% silver-palladium alloy with a thickness of 0.08 mm and a width of 2 mm was bonded to this material by thermocompression, and rolling and solution treatment were repeated to obtain a clad material with a total thickness of 0.08 mm and a noble metal thickness of 8 microns. After hardening this clad material in a non-oxidizing atmosphere at a temperature of 300℃ for 2.5 hours, it was punched out using a press and bent into a dogleg shape to create a brush with a thickness of 0.08 mm, a width of 1.0 mm, and a length of 20 mm. It was created.

[Conventional example]

A 2% beryllium-copper alloy sheet material with a thickness of 0.5 mm and a width of 20 mm is directly bonded to a 30% silver-palladium alloy with a thickness of 0.2 mm and a width of 2 mm.Then, the sheet material is rolled and solution-treated repeatedly to obtain a total thickness of 0.08 mm (precious metal). A cladding material with a thickness of 40 microns was obtained. After hardening the clad material in a non-oxidizing atmosphere at a temperature of 300°C for 2.5 hours, it was punched out using a press and bent into a dogleg shape to form a material with a thickness of 0.08 mm, a width of 1.0 mm, and a length of 20 mm. Created a brush.

The above example and conventional example are 75% gold - 6% platinum -
Diameter 40mm made of 6% silver-12% copper-1% zinc alloy
Rotating sliding disk of φ, 1800 revolutions per minute, current
The test was conducted at 100-200 mA and a contact pressure of 25 g.

At the start of the test, the distance was 3 m for both the example and the conventional example.
Although it showed a low contact resistance of Ω, after 300 hours, the conventional example showed severe scratches due to mechanical wear. On the other hand, in the examples, no mechanical wear was observed and the contact resistance pressure was stable. This is probably due to the very high hardness of the contact surface, approximately 200Hv.

The above-mentioned examples are made by cladding a copper-titanium alloy with a silver-palladium alloy, cladding a 17-7PH stainless steel with a silver-palladium-copper alloy, or cladding a copper-nickel-tin alloy with a gold-silver-copper alloy. A similar effect was shown when replacing it with a clad dress.

As detailed above, according to the manufacturing method of the sliding contact of the present invention, a high hardness that could not be achieved conventionally can be obtained, and an excellent material with stable contact resistance and wear resistance even under high contact pressure can be obtained. Contacts can be manufactured.

Claims (1)

[Claims] 1. A noble metal material with excellent malleability is bonded to a chemically pretreated precipitation hardening spring material, and this clad material is rolled to a thickness of 10 microns or less, followed by precipitation hardening treatment. A method for manufacturing a sliding contact, characterized in that the surface of the noble metal layer is a hardened layer.