Motor

Abstract

A motor includes a yoke housing, an armature, a commutator, a brush, a brush holder, and a yoke side joining part. The yoke housing has an opening. The armature is received by the yoke housing. The commutator is joined to the armature. The brush supplies electricity to the commutator. The brush holder holds the brush. The yoke side joining part connects the brush holder and the yoke housing. The yoke side joining part has an elastic member at an end part of the yoke side joining part. The end part is on a side of the yoke housing. A loss tangent of the elastic member is equal to or larger than 0.6.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with additional objectives, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which:

FIG. 1 is a cross-sectional view of a motor according to an embodiment of the present invention;

FIG. 2 is an illustrative cross-sectional view showing a joining area between an end plate and a yoke housing;

FIG. 3 is a graph showing a relationship between a loss tangent of an elastic member and an operation noise of the motor; and

FIG. 4 is a cross-sectional view of a motor according to another embodiment.

Claims

1. A motor comprising: a yoke housing that has an opening;an armature that is received by the yoke housing;a commutator that is joined to the armature;a brush that supplies electricity to the commutator;a brush holder that holds the brush; anda yoke side joining part that connects the brush holder and the yoke housing, wherein the yoke side joining part has an elastic member at an end part of the yoke side joining part, wherein: the end part is on a side of the yoke housing; anda loss tangent of the elastic member is equal to or larger than 0.6.

2. The motor according to claim 1, wherein: the yoke side joining part has an end bracket that blocks the opening of the yoke housing, and the elastic member that is placed in a gap between the end bracket and the yoke housing; andthe brush holder is fixed on a predetermined position of the end bracket.

3. The motor according to claim 2, wherein: the elastic member has a plate-like shape;thickness of the elastic member is larger than a size of the gap between the end bracket and the yoke housing; andthe yoke housing, the elastic member, and the end bracket are sequentially arranged in a direction of a rotational axis of the armature.

4. The motor according to claim 1, wherein a modulus of restitution elasticity of the elastic member is equal to or smaller than 35%.

5. A motor comprising: a yoke housing that has an opening;an armature that is received by the yoke housing;a commutator that is joined to the armature;a brush that supplies electricity to the commutator;a brush holder that holds the brush; anda gear side joining part that connects the brush holder and a gear housing that receives a transmission device, wherein:the transmission device transmits power of the motor;the armature has a rotational axis, one end of which is joined to the transmission device; andthe gear side joining part has an elastic member at an end part of the gear side joining part, wherein: the end part is on a side of the gear housing; anda loss tangent of the elastic member is equal to or larger than 0.6.

6. The motor according to claim 5, wherein: the gear side joining part has an end bracket and the elastic member, wherein: the end bracket blocks the opening of the yoke housing and has a hole, in which the one end of the rotational axis of the armature is inserted; andthe elastic member is placed in a gap between the end bracket and the gear housing; andthe brush holder is fixed on a predetermined position of the end bracket.

7. The motor according to claim 6, wherein: the elastic member has a plate-like shape;thickness of the elastic member is larger than a size of the gap between the end bracket and the gear housing; andthe gear housing, the elastic member, and the end bracket are sequentially arranged in a direction of a rotational axis of the armature.

8. The motor according to claim 5, wherein a modulus of restitution elasticity of the elastic member is equal to or smaller than 35%.