| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC motor for inexpensively improving a lifetime of a brush by sharing a setting of a brush movement angle (a brush shift) with right and left rotations. SOLUTION: A surface of a commutator 8 are formed with a plurality of grooves 10 in the slide direction of the brush 2 within a range in which the brush 2 slides, and have an uneven contact face with the brush 2. The brush 2 has the movement angle (the brush shift) set to 0°regardless of the rotative direction of an armature 1. Since a state that the brush 2 slides and contacts the commutator 8 is drastically stabilized, an effect of a voltage rectification is effectively utilized regardless of the movement angle (the brush shift) of the brush 2 set to 0°. As a result, a distribution of a current carried on the contact face between the brush 2 and the commutator 8 is deviated to an entrance of the brush 2 in the rotative direction of the armature 1, an effect for improving the rectification is obtained and is the same as an effect for delaying the movement angle (the brush shift) of the brush 2, and the lifetime of the brush can be improved. COPYRIGHT: (C)2008,JPO&INPIT
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