JPH01202135A - Brush contact structure for motor - Google Patents

Abstract

PURPOSE:To improve reliability, by forming the sliding section of a brush in contact with a commutator, with a plurality of layers, in the rotational direction of a motor, and by using high resistance material for both the ends of a plurality of the layers, to use low resistance material for an intermediate layer. CONSTITUTION:The sliding surface material of a brush is composed of a plurality of layers 1b, 1a, 1c, and a plurality of the layers are arranged in the order of high resistance material, low resistance material, and high resistance material, to a commutator segment when a motor is rotated. At the time of normal rotation when the gap of the commutator segment 3 is in the layer 1a, arc is not generated. However, when current flowing through a coil, between the layer 1c and a commutator segment 3c is forced to be turned off, or when a coil 5b is short-circuited between the layer 1b and a commutator segment 3c, the arc is generated. Then, for both the end surfaces, the high electric resistance material of high arc resistance is used, and for the internal section, low resistance material for lowering contact resistance is used, and reliability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a brush contact structure for a motor having a commutator.

BACKGROUND OF THE INVENTION In recent years, a single motor has been increasingly used in a wide variety of situations. For this reason, attempts have been made in the past to improve reliability by improving the brush material or by using a plurality of brushes, but this has not been sufficient, and there is a need for a brush contact structure that can be used over a wide range of applications.

An example of the brush contact structure of the above-mentioned conventional motor will be described below with reference to the drawings.

FIG. 3 shows the contact structure of a conventional motor.

In FIG. 3, 3 is a commutator piece, 4 is a mold for fixing the commutator piece 3, 6a and 6b are brush contacts that come into contact with the commutator piece 3, and 7 is a leaf spring that holds the carbon brushes 6a and 6b. The brush contacts 6 a p 6 b are made of the same material and are divided into two parts in order to increase the rectifying area and improve the reliability of the contact parts.

Problems to be Solved by the Invention However, in the above configuration, the brush contacts 6a, 6
Since b is made of a single material, it is difficult to select a material that simultaneously satisfies contradictory properties such as arc resistance under high loads and high speeds and low contact resistance under low loads and low speeds, which are necessary for wide range of use. There was a point.

In view of the above-mentioned problems, the present invention provides a brush contact structure for a motor that is highly reliable under a wide range of usage conditions.

Means for Solving the Problems In order to solve the above problems, the brush contact structure of the present invention is such that the sliding portion of the brush that contacts the commutator is formed of a plurality of layers in the rotational direction of the motor. A high-resistance material is arranged as the layers at both ends of the layer, and a low-resistance material is arranged as the center layer.

Function: With the above-described configuration, the present invention provides arc resistance at the end portions and low contact resistance inside, making it possible to achieve high reliability under a wide range of usage conditions.

EXAMPLE Hereinafter, a brush contact structure of a motor according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a perspective view of a brush contact structure of a motor in an embodiment of the present invention. In Fig. 1, 1 is a brush contact, 2 is a leaf spring that holds the brush contact 1, and 3 is a brush contact 1.
4 is a mold that fixes the commutator piece 3 in contact with the commutator piece 3. The brush contact 1 has a layer 1b of high resistance material in the direction of rotation of the motor.

ICs are arranged in the layer 1a made of a low resistance material and the layer 1a made of a high resistance material, and the respective layers are connected.

The brush contact structure of the motor configured as above is shown in Figures 1 and 2 (a), (b), and (c) below.
The operation will be explained using .

First, Figures 2 (a), (b), and (C) show when the commutator current is switched, and Figure 2 (a) is during normal rotation, with no arc occurring and the brush contact 1 There is no need for arc resistance. However, in the state shown in FIG. 2(b), an arc is generated between the brush layer 1c and the commutator piece 3a because the current flowing in the coil is cut off.

Further, as shown in FIG. 2(C), an arc is generated to short-circuit the coil 5b between the brush layer 1b and the commutator piece 3c. As mentioned above, it can be seen that arc resistance is required at both end faces of the brush. Therefore, by using a high-resistance material with high arc resistance for both end faces, and by selecting a low-resistance material that can lower contact resistance for the inside, it is possible to provide arc resistance without reducing the contact resistance of the brush over a wide range of areas. It becomes possible to use

As described above, according to this embodiment, the material of the sliding surface of the brush is composed of a plurality of layers 1a, lb, and lc, and the plurality of layers are made of a material with high resistance and a material with low resistance against the commutator pieces when the motor rotates. By arranging the material so that it changes sequentially with high resistance material, it can be used in a wide range of applications and has high reliability.

Effects of the Invention As described above, the present invention can be used over a wide range of applications by forming the sliding part of the brush with multiple layers in the motor rotation direction, and arranging high-resistance materials as the layers at both ends and low-resistance materials as the center layer. It is possible to provide a highly reliable motor that can be used for many purposes.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the brush contact structure of a motor in an embodiment of the present invention, FIGS. 2(a), (b), and (C) are diagrams showing the action of the brush in the same embodiment, and FIG. FIG. 2 is a perspective view of a conventional brush contact structure. 1...Brush contact, 1a...Low resistance material layer, 1b. 1c... Layer of high resistance material, 3... Commutator piece. 1 to--1-' 1-11-I/ Figure 3

Claims (1)

[Claims] The sliding portion of the brush that comes into contact with the commutator pieces is formed of a plurality of layers in the rotational direction of the motor, and among the plurality of layers, a high resistance material is arranged as the layers at both ends, and a low resistance material is arranged as the center layer. Motor brush contact structure.