JPH0323636B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a material for making a contact piece that is fixed to the outer peripheral surface of a cylindrical commutator and brought into contact with a comb-like sliding brush.

Conventionally, this type of commutator contact piece materials include Cu,
Cu alloys such as Cu-Zn have been used, but if a contact piece made of these materials is fixed to the outer circumferential surface of a cylindrical commutator and a comb-shaped sliding brush is brought into contact with it, it is possible to , when the contact piece slides due to the rotation of the commutator, the contact piece will be significantly worn due to electrical and mechanical erosion, the contact pressure of the sliding brush will be low, the contact resistance will increase significantly, and the rotation of the commutator This causes unevenness. For this reason, it may be possible to increase the contact pressure of the sliding brush in advance, but if this is done, the contact pieces will wear out even more due to electrical and mechanical erosion.
It becomes unusable in a short period of time and its lifespan is significantly shortened. Further, since the contact piece made of the above-mentioned material is chemically unstable, initial welding may occur immediately after the contact piece starts sliding with the sliding brush.

The present invention has been made to solve these problems, and aims to provide a contact piece material that is resistant to wear and does not cause initial welding.

The commutator contact piece material of the present invention has two layers of coating applied to the surface of Cu or Cu alloy, the first layer being Cr,
Either Re is 1 to 30 μm thick, the second layer is Au,
Either Ag, Au-Ag or Ag-Pd has a thickness of 0.1~
It is characterized by a coating of 20 μm.

The reason why the surface of Cu or Cu alloy is coated with either Cr or Re to a thickness of 1 to 30 μm is to impart mechanical hardness to the contact piece material made of Cu or Cu alloy. This is because if the thickness is less than 1 μm, there is no effect, and if the thickness exceeds 30 μm, it will mechanically erode the sliding brush on the other side that comes into contact with it, accelerating wear. In addition, on the surface of either this Cr or Re coating,
Thickness of Au, Ag, Au-Ag, Ag-Pd
The reason for coating the first layer with a thickness of 0.1 to 20 μm is to further chemically stabilize the surface of the first layer coating, prevent electrical corrosion, and prevent initial welding immediately after the start of sliding.
There is no effect if the thickness is less than 0.1μm, and if the thickness is 20μm
This is because, if it exceeds 100%, the chemical stability of the surface will not be improved any further, and expensive precious metals will only be wasted.

Next, in order to clarify the effects of the commutator contact piece material according to the present invention, specific examples and conventional examples thereof will be described.

Example 1 A 10 μm thick Cr plating was applied to the surface of a 1 mm thick Cu plate, and a 10 μm thick Au plate was applied to the Cr plated surface.
A contact piece material was obtained by plating.

Example 2 A 15μ thick plate was placed on the surface of a 1 mm thick Cu-Ni 30% by weight plate.
A contact piece material was obtained by applying 30 wt % Ag-Pd plating to a thickness of 10 μm on the re-plated surface.

Example 3 A 10μ thick plate was placed on the surface of a 1mm thick Cu-Zn 20% by weight plate.
A contact piece material was obtained by applying 10% by weight Au-Ag plating to a thickness of 2 μm on the re-plated surface.

Conventional examples 1, 2, 3 1 mm thick Cu plate, 1 mm thick Cu-Zn 20% by weight
Plate, 1 mm thick contact piece material consisting of 30% by weight Cu-Ni.

Now, contact pieces with a width of 7 mm and a length of 10 mm are made using the contact piece materials of Examples 1 to 3 and Conventional Examples 1 to 3, and these are placed at equal intervals on the outer peripheral surface of a commutator with a diameter of 7 mm and a length of 10 mm. Three pieces are fixed together, and a comb-shaped sliding brush made of phosphor bronze (thickness 0.2 mm, width 8 mm, length 10 mm, with three brush strips each 2 mm wide and 8 mm long at 1 mm intervals) When a sliding test was conducted with a contact force of 15 g and a contact resistance of 20 mΩ, Conventional Examples 1 to 3
A commutator with a contact piece made of contact piece material is
After a 10-hour continuous test, a contact piece with a thickness of 1 mm was 0.2
A large amount of wear occurs from mm to 0.24 mm, and the contact resistance is 110
It increased significantly to ~340 mΩ, and the rotation of the commutator became uneven. Furthermore, when the sliding test was continued, all of them became unusable after 25 to 30 hours. On the other hand, commutators with contact pieces made of the contact piece materials of Examples 1 to 3 had contact pieces with a thickness of 1 mm ranging from 0.05 mm to 0.1 mm after a 10-hour continuous test.
There was only a small amount of abrasion (mm), the contact resistance increased only slightly (40 to 50 mΩ), and the commutator rotated without any unevenness. In addition, we will continue to carry out sliding tests.
After 25 hours of continuous use, the amount of wear was minimal and nothing became unusable.

In addition, there were as many as 3 out of 100 commutators with contact pieces made from the contact piece materials of Conventional Examples 1 to 3 that were initially welded to the sliding brush immediately after the start of the sliding test. None out of 100 commutators had contact pieces made from contact piece materials 1 to 3.

In the embodiments of the present invention, the contact piece material is coated by plating, but the coating is not limited to this, and may be applied by sputtering, ion plating, thermal spraying, vapor deposition, or other means.

As detailed above, the commutator contact piece material of the present invention has a surface of Cu or a Cu alloy coated with either Cr or Re, and the surface is coated with Au, Ag, Au-Ag,
Since the surface layer is coated with Ag-Pd, the surface layer has high mechanical hardness and is chemically stable. The amount of wear of the contact piece due to electrical and mechanical erosion during rotation and sliding with the sliding brush is extremely small. Therefore, the contact pressure of the sliding brush hardly changes and the contact resistance does not increase significantly, so the rotation of the commutator does not occur unevenly and the life of the commutator is extended. Furthermore, since the surface layer is chemically stable as described above, it has excellent effects such as being able to prevent initial welding with the sliding brush immediately after the rotation and sliding start.

Claims (1)

[Claims] 1. In a commutator contact piece material made of Cu or Cu alloy, the surface of the contact piece material is coated with two layers, and the first layer is made of either Cr or Re with a thickness of 1 to 30 μm.
m. A contact piece material for a commutator, characterized in that the second layer is a coating of Au, Ag, Au-Ag, or Ag-Pd with a thickness of 0.1 to 20 μm.