JPH06113506A - Brush for motor - Google Patents

Abstract

PURPOSE:To provide a brush for motor in which service life is prolonged while suppressing noise. CONSTITUTION:Carbon terminal 3 of a motor brush has a multilayer terminal body 30 in which the hardness of material increases from side A, where the multilayer part slides 31 on a commutator, toward side B where the multilayer part is fixed to a terminal spring board. Since the carbon terminal 3 has a sliding tip made of soft material layer, the sliding face gradually follows the surface profile of commutator while initially exhibiting silencer effect and then makes a transition to hard material layer thus realizing noise reduction and long service life.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brush for a motor.

[0002]

2. Description of the Related Art As shown in FIGS. 6 and 7, a conventional brush of a motor has a carbon terminal 3 on a tip side of a terminal spring plate 2.
It is formed by fixing. The carbon terminal 3 is in sliding contact with the commutator piece 5 of the commutator 4 to supply electricity to the coil to rotate the motor. In the figure, 7 is a rotor of a motor, 8 is a stator, 9 is a bearing stand, and 10 is a case.

[0003]

Here, when the motor rotates, a sliding noise is generated between the terminal 3 and the commutator piece 5 of the commutator 4, as shown in FIG. Then, there is a problem that an impact sound is generated due to a step in the slit 6 between the commutator pieces 5, and the sound becomes loud.

To solve this problem, the terminal 3 of the brush 1
This was done by softening the carbon material, but there is a drawback that if this material is soft, the life will be shortened due to friction.

An object of the present invention is to provide a brush for a motor that is quiet and has a long life.

[0006]

In the brush of the motor of the present invention, the carbon terminal of the brush slidingly contacting the commutator is formed such that the hardness is higher from the lower side than the side slidingly contacting the commutator. is there.

[0007]

According to the constitution of the brush of the motor of the present invention, since the sliding contact tip of the carbon terminal is the soft material layer, the soft material is initially used to produce a silent effect, and the surface of the commutator is gradually increased. The sliding contact surface conforms to the shape, and the familiar shape is transferred to the hard material layer, which is quiet against friction and has a long life.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given below with reference to the drawings shown as the embodiments of the present invention.

The carbon terminal 3 of the brush of the motor of the present invention
As shown in FIG. 1, the terminal main body 30 is formed in a multi-layer structure, and the multi-layer portion of the surface 31 is in sliding contact with the commutator 4.
From the A side to the B side of the mounting portion 32 mounted on the terminal spring plate 2 so that the hardness changes from a soft material layer to a hard material layer from a low hardness state to a high hardness layer.
As shown in FIG. 2, the terminal main body 30 is pressed against the commutator 4 by the terminal spring plate 2 to make sliding contact therewith. In the initial sliding state, the soft material layer facilitates familiarization with the commutator 4 and friction. The resistance is low, the noise is low, the material layer becomes harder gradually, and the life can be extended against friction.

FIG. 3 shows another embodiment of the present invention. The terminal body 30 of the carbon terminal 3 has a soft material portion 3b and a hard material portion 3 from the surface 31 side in sliding contact toward the mounting portion 32 side.
It is formed by changing the ratio with a so that the hard material portion 3a is increased. Although it is formed in a diagonally divided state in FIG. 3, it is also possible to take another form and change the ratio.

FIG. 4 shows another embodiment of the present invention, in which the carbon particle diameter of the terminal body 30 of the carbon terminal 3 is increased from the A side to the B side of the sliding contact surface 31 of the commutator 4 from small to large. In the initial stage of sliding contact, the carbon is easily scraped off and the frictional resistance is low so that noise can be reduced, and the particle diameter becomes large as the carbon terminal 3 becomes more familiar with the commutator 4 and becomes longer. Life can be extended.

FIG. 5 shows still another embodiment of the present invention, in which the surface of the sliding contact surface 31 of the carbon terminal 3 is coated with a surface coating layer 11 made of a conductive and soft material such as Au, Ag, Ni. In addition, it is possible to improve the familiarity of the initial sliding contact surface with the commutator 4 and to reduce noise.

[0013]

In the brush of the motor of the present invention, the carbon terminal of the brush that is in sliding contact with the commutator is formed so that the hardness becomes higher from the lower side than the side that contacts the commutator. A soft material with low hardness is easy to fit in a commutator, and there is little friction or impact noise, and quiet noise can be achieved. It can have a long life.

[Brief description of drawings]

FIG. 1 shows a carbon terminal according to an embodiment of the present invention, (a) is a front view thereof, and (b) is a side view thereof.

FIG. 2 is an enlarged view of a main part showing a sliding contact state of the brush of the embodiment of the present invention with a commutator.

FIG. 3 is a front view of another embodiment of the present invention.

FIG. 4 is a schematic front view of another embodiment of the present invention.

FIG. 5 is a front view of still another embodiment of the present invention.

FIG. 6 is a sectional view of a conventional motor.

7 is a cross-sectional view taken along the line AA of FIG. 6 showing a sliding state between a brush terminal and a commutator.

[Explanation of symbols]

 1 brush 2 terminal spring plate 3 carbon terminal 30 terminal body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsutomu Natsuhara 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd.

Claims (1)

[Claims] 1. A brush for a motor, characterized in that the carbon terminal of the brush that is in sliding contact with the commutator is formed so that the hardness is higher from the lower side than the side that is in sliding contact with the commutator.