JPS61136645A - Sliding contact material - Google Patents

Abstract

PURPOSE:To improve the wear resistance of the contact chips of a commutator by dispersing uniformly and finely prescribed percentages of the oxides of Cd and Al and/or Ga in Ag and using the resulting material having increased lubricity and an increased softening temp. CONSTITUTION:A sliding contact material is obtd. by dispersing uniformly and finely 0.5-15wt% Cd oxide and 0.1-5wt% Al oxide and/or Ga oxide in Ag. The content material has the increased lubricity and an increased softening temp. by the oxides dispersed uniformly and finely in Ag. When the contact chips of a commutator are made of the contact material, the wear resistance of the contact chips is improved.

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 of the present invention is to provide a sliding contact material in which oxides are uniformly and finely dispersed in Ag to reduce wear t- and have a low and stable contact resistance. It is something.

(Structure of the Invention) The sliding contact material of the present invention contains 0.0% Cd oxide in Ag.
It is characterized by uniformly and finely dispersing 5 to 15% by weight and at least one of Al and Ga oxides in an amount of 0.1 to 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, there is a small amount of oxides of AI and Ga (both types are 0.1 to 0.1
The reason why 5% by weight is added is to increase the softening temperature, suppress adhesion during the rubbing operation, and improve wear resistance, and 0.1% by weight.
If it is less than 5% by weight, there is no effect, and if it exceeds 5% by weight, processing becomes difficult.

(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 0.2H 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 on the left side of the table below. A commutator 1 with a diameter of 12B and a length of 8 fl has three contact pieces on the outer circumference as shown in the drawing.
A commutator rotation test was carried out under the test conditions described below by bringing brush contacts 3 having two brush wires 2 of 0.7 m in diameter and 8 m in length made of Pt into contact with each other so as to face each other. When the wear amount and contact resistance of piece 1a were measured, the results shown in the right column of the table below were obtained.

Test conditions Voltage: DC12V Current: 0.6A Commutator rotation speed: 1000rpm Commutator rotation time Near time Brush contact contact crab 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 6
．． It can be seen that the wear resistance is significantly reduced in the range of 3 to 7.2 cm, indicating that the wear resistance is excellent. 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 child contact piece 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--1--Commutator, la-...-Contact piece, 2--
-Brush wire, 3.--Brush contact.

Claims (1)

[Claims] In Ag, 0.5 to 15% by weight of Cd oxide and Al, G
A sliding contact material characterized in that 0.1 to 5% by weight of at least one oxide of (a) is uniformly and finely dispersed.