JPH06172894A - Sliding contact point material and its production - Google Patents

Abstract

PURPOSE:To provide a working method for a sliding contact point material where wear resistance is improved and the generation of wear particle and the occurrence of noise is prevented. CONSTITUTION:This material is a contact point material where a Cu alpha phase of <=2mum average grain size is finely and uniformly dispersed in an Agalpha phase in an AgCu alloy containing 0.1-8wt.% Cu and which further contains at least one or more elements selected from Ge, Ni, Sn, In, Zn, Mg, Mn, Sb, Pb, and Bi by 0.1-2wt.%. The contact point material is held at a temp. not higher than the solidus temp. in the AgCu binary system phase diagram of the composition and not lower than the solubility curve temp., cooled rapidly, cold-worked at >=50% draft, heat-treated at 200-600 deg.C for 0.1-1hr, and then cold-worked at >=30% draft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding contact material and a processing method thereof, and more particularly to a commutator material and a processing method suitable for a micromotor.

[0002]

2. Description of the Related Art Ag has been conventionally used as one of sliding contact materials.
Although a Cu alloy has been used, the metal structure of the AgCu alloy is not sufficiently controlled, and some Cu atoms are solid-solved in the Agα phase depending on processing conditions, and the rest is Cuα.
It was dispersed in the Agα phase as a phase. These Cu particles are oxidized during sliding and become oxide particles to serve as a lubricant.
That amount was not enough. Further, since the solid solution amount of Cu atoms in the Agα phase is small, the solid solution hardening is small, and as a result, the effect of reducing the wear caused by the softening of the material during sliding is insufficient. Therefore, some of the materials wear rapidly during sliding due to variations in the metal structure during manufacturing, and the wear resistance was insufficient. In addition, in the case of a micromotor whose commutator is made of this material, a large amount of abrasion powder is generated due to sliding with the brush contact, which causes noise.

[0003]

SUMMARY OF THE INVENTION Therefore, the present invention is intended to provide a sliding contact material having improved wear resistance, reduced generation of abrasion powder and suppressed generation of noise, and a method of processing the same. Is.

[0004]

One of the sliding contact materials of the present invention for solving the above-mentioned problems is an AgCu alloy containing 0.1 to 8% by weight of Cu and having an average particle size of Cuα phase of 2 μm or less. And is uniformly dispersed in the Agα phase.

Another one of the sliding contact materials of the present invention is the above sliding contact material, further comprising Ge, Ni, Sn and I.
It is characterized by containing 0.1 to 2 wt% of at least one selected from n, Zn, Mg, Mn, Sb, Pb and Bi.

In the method for producing a sliding contact material of the present invention, one of the above two sliding contact materials is used in the composition A
Hold at temperatures below the solidus temperature and above the solubility curve temperature in the gCu binary system diagram, then quench, then cold work at a working rate of 50% or more, and then at 200-600 ℃
It is characterized in that heat treatment is carried out for 0.1 to 1 hour, and then cold working is carried out at a working rate of 30% or more.

[0007]

As described above, one of the sliding contact materials of the present invention is that the Cu particles having an average particle diameter of 2 μm or less are uniformly and finely dispersed in the Agα phase. Oxidize into oxide particles, which act as a lubricant to reduce wear. Here, the particle size of the Cu particles is set to 2 μm or less because there is a problem that the lubricating effect is lost when the particle size is larger than 2 μm.

Further, the above sliding contact materials are Ge, Ni,
By containing at least one selected from Sn, In, Zn, Mg, Mn, Sb, Pb and Bi in the range of 0.1 to 2% by weight, the effect of reducing wear is further improved. The range of inclusion here is 0.1 to 2% by weight
The reason is that if it is less than 0.1% by weight, the effect of reducing wear by addition cannot be exhibited, and if it exceeds 2% by weight, the contact resistance becomes too high.

Further, according to the method for producing a sliding contact material of the present invention, the AgCu alloy material is subjected to solution treatment, the precipitated particles of Cu are supported and solid-solved, and then cold working and heat treatment are carried out, whereby the Agα phase is formed. Cu particles can be uniformly and finely deposited. The cold working after the solution treatment is set to a working rate of 50% or more because if it is less than 50%, the precipitation of Cu will be non-uniform due to the subsequent heat treatment. The reason that cold working for finishing is performed at a working rate of 30% or more is to work-harden the material softened by heat treatment.
If the processing rate is less than%, sufficient work hardening cannot be obtained. The sliding contact material of the present invention produced in this way has a significantly improved wear resistance. The noise caused by the powder can be reduced.

[0010]

EXAMPLES Examples of the sliding contact material of the present invention and a method for producing the same will be described together with comparative examples and conventional examples. The material of Example 1 having the composition shown in Table 1 below was held at 750 ° C. for 1 hour, cooled with water, and then wire-drawn at a working rate of 51%, and further heat treated at 400 ° C. for 1 hour. After that, wire drawing was performed at a processing rate of 49%. Examples 2-12 and Comparative Examples 1-
Material No. 2 is kept at 700 ° C for 30 minutes, cooled with water, then drawn at a working rate of 51%, heat-treated at 300 ° C for 1 hour, and then drawn at a working rate of 49%. Processing was performed. The material of the conventional example was held at 550 ° C. for 1 hour, air-cooled, and then drawn at a working rate of 49%.

[0011]

[Table 1]

The lattice constant of the Agα phase of the material thus manufactured was 4.077Å in Example 1, 4.083Å in Example 2,
It was 4.063Å in the conventional example. According to Vegard's law, the solid solution amounts of Cu in Examples 1, 2 and the conventional example were 1.2% by weight, 0.39% by weight and 3% by weight, respectively.

However, Examples 1 to 12 and Comparative Example 1 having the above composition
As a test material of ~ 2 and the conventional example, a round bar having a diameter of 2 mm was used, and a cross bar was crossed with a round bar of Ag-Pd50% having the same diameter, and a sliding test was performed under the following test conditions, and the wear amount and contact resistance Was obtained, the results shown in Table 2 below were obtained.

Test conditions Current DC 170mA Sliding contact 20mm / sec Load 25g Test time 333 minutes Temperature 25 ° C Humidity 50% RH

[0015]

[Table 2]

As can be seen in Table 2 above, Examples 1-12
It can be seen that the sliding contact material of (1) has a significantly smaller amount of wear than the sliding contact material of the conventional example, and the contact resistance is significantly low. The sliding contact material of Comparative Example 1 has a large amount of wear in spite of low contact resistance, and the Comparative Example 2 has a problem of high contact resistance in spite of a small amount of wear. It is inferior to contact materials.

[0017]

As described above, the sliding contact material of the present invention is
Since the Cu particles are uniformly and finely dispersed in the gα phase, the Cu particles oxidize during sliding to become oxide particles, which serve as a lubricant, which reduces wear. Furthermore, Ge, Ni, Sn, In, Zn, Mg, Mn, Sb,
Wear is reduced by adding at least one of Pb and Bi. Further, if the solution-treated material is heat-treated as it is, Cu particles are discontinuously precipitated from the grain boundaries of the Agα phase, resulting in very unevenness. However, the method for producing the sliding contact material of the present invention By including a cold working step with a working ratio of 50% or more between the solution treatment and the heat treatment as described above, the precipitation of Cu particles becomes extremely fine and uniform. Further, by performing cold working at a working rate of 30% or more after heat treatment, work hardening is performed and wear resistance is improved.

Therefore, the sliding contact made of this material can reduce the abrasion during sliding with the brush contact, and can significantly reduce the noise caused by the abrasion powder.

Claims (4)

[Claims] 1. AgCu containing 0.1 to 8% by weight of Cu
In the alloy, the Cuα phase has an average grain size of 2 μm or less
A sliding contact material characterized by being uniformly and finely dispersed in the α phase. 2. The contact material further comprises Ge, N
i, Sn, In, Zn, Mg, Mn, Sb, Pb and B
0.1 to 2% by weight of at least one selected from i
The sliding contact material according to claim 1, wherein the sliding contact material is contained. 3. AgCu containing 0.1 to 8% by weight of Cu
The alloy is maintained at a temperature below the solidus temperature and above the solubility curve temperature in the AgCu binary system phase diagram in that composition, then quenched, then cold worked at a working rate of 50% or more, and then 200- A method for producing a sliding contact material, which comprises performing heat treatment at 600 ° C for 0.1 to 1 hour and then cold working at a working rate of 30% or more. 4. The AgCu alloy further comprises Ge, N
i, Sn, In, Zn, Mg, Mn, Sb, Pb and B
0.1 to 2% by weight of at least one selected from i
The method for producing a sliding contact material according to claim 3, wherein the sliding contact material is contained.