JPS61133347A - Sliding contact point material - Google Patents

Abstract

PURPOSE:To reduce and stabilize the contact resistance of the sliding contact point material, by dispersing an oxide of Cd and each oxide of Si and Zr in Ag finely and uniformly. CONSTITUTION:The sliding contact point material is manufactured by dispersing, by weight, 0.5-15% CdO and 0.1-5%, in total, of SiO2 and ZrO2 in Ag finely and uniformly. The softening temp. as well as the lubricating ability of this material is increased because of the fine and uniform dispersion of the above oxides in the Ag, so that the wear resistance of, e.g., a contact of a commutator of small-sized motor made of this material can be improved. Moreover, no oxide film is formed on the sliding surface, so the contact resistance can be reduced and stabilized and the variance in the number of revolutions of the commutator can be reduced.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to improvements in sliding contact materials.

(Prior art and problems) Conventionally, Ag-Cd alloy has been mainly used as a sliding contact material for making contact pieces around the commutator of small motors, but it softens during the rotational sliding operation of the commutator. There were disadvantages in that the contact pieces adhered to each other, causing a lot of wear, and oxidized, making the contact resistance unstable and causing variations in the commutator rotational speed.

(Object of the Invention) The present invention was made in view of the above circumstances, and an object thereof is to provide a sliding contact material that reduces wear by uniformly and finely dispersing oxides in Ag, and has a low and stable contact resistance. It is.

(Structure of the Invention) The sliding contact material of the present invention contains 0.0% Cd oxide in Ag.
5 to 15% by weight and a total of 0.1% of Si and Zr oxides
It is characterized by being uniformly and finely dispersed at ~5% by weight.

In the sliding contact material of the present invention, Cd is added to Ag.
The purpose of uniformly and finely dispersing 0.5 to 15% by weight of oxides is to increase the lubricity and improve the wear resistance of Ag.
If it is less than 0.5% by weight, there is no effect, and if it exceeds 15% by weight, the contact resistance becomes high and unstable.

Furthermore, the total amount of oxides of St and Zr is 0.1 to 5% by weight.
The purpose of adding it is to raise the softening temperature and suppress adhesion during the grinding operation to improve wear resistance. If it is less than 0.1% by weight, it has no effect, and if it exceeds 5% by weight, it is difficult to process. This is the result.

(Embodiments and Conventional Examples) Contact pieces on the outer periphery of a commutator of a small motor made of a sliding contact material according to the present invention and a conventional sliding contact material will be described.

A contact piece with a thickness of 0.2 mm was made using a sliding contact material according to an embodiment of the present invention (made by internal oxidation method) and a conventional sliding contact material having the composition shown in the left column of the table below. As shown in the drawing, three of these contact pieces were placed on the top and bottom of the outer circumferential surface of a commutator 1 with a diameter of 12 mm and a length of 8 mm.
Diameter 0.7 made of Pt! , the brush contacts 3 having two brush wires 2 each having a length of 8 cm are brought into contact so as to face each other,
A commutator rotation test was conducted under the test conditions described below, and contact piece 1
When the wear amount and contact resistance of a were measured, the results shown in the right column of the table below were obtained.

Test conditions Voltage: D012V Current: 0.6A Commutator rotation speed: 1000 rpm Commutator rotation time Near time Contact crab of brush contact 100g As is clear from the table above, the amount of wear on the conventional contact piece is 9
．． 2 ■, whereas the amount of wear of the contact piece in the example was 5
．． It can be seen that the wear resistance is significantly reduced in the range of 9 to 6.3 cm, indicating excellent wear resistance. Furthermore, it can be seen that the contact resistance of the commutator having the contact pieces of the example is lower and more stable than the contact resistance of the commutator having the contact pieces of the conventional example.

(Effects of the Invention) As detailed above, the sliding contact material of the present invention has oxides uniformly and finely dispersed in Ag and has high lubricity and softening temperature. The wear resistance of the commutator contact pieces is significantly improved. Further, since no oxide film is formed on the sliding surface, the contact resistance is low and stable, and there are excellent effects such as extremely small variations in the rotation speed of the commutator of a small motor.

[Brief explanation of drawings]

The figure is a perspective view showing the state of contact between the commutator and brush contacts of a small motor. 1...---m commutator, 1a...----contact piece, 2-
-----One brush wire, 3-・--・-brush contacts.

Claims (1)

[Claims] A sliding contact material characterized in that 0.5 to 15% by weight of Cd oxide and 0.1 to 5% by weight of Si and Zr oxides are uniformly and finely dispersed in Ag.