To reduce an internal short current flowing between segments 2a of a commutator 2.
A brush 3 comprises conducting materials 3a and insulating layers 3b alternately disposed in their width direction corresponding to the circumferential direction of the commutator 2. A width B of the conducting material 3a is narrower than a width A of the insulating part 2b in the commutator 2. The conducting materials 3a are connected to a pigtail 4 attached to an upper end of the brush 3. When the segments 2a adjacent in the circumferential direction of the commutator 2 are shorted through the brush 3, the current does not directly flow from the first conducting material 3a1 to the second conducting material 3a2 since the insulating layer 3b intervenes between the first conducting material 3a1 contacting one segment 2a1 and the second conducting material 3a2 contacting another segment 2a2, and the internal short current is reduced by an increase of resistance since the current flows from the conducting material 3a1 to the second conducting material 3a2 through the pigtail 4.
| JPS61210853 | BRUSH DEVICE FOR MINIATURE MOTOR |
| JP3520299 | MANUFACTURE OF BRUSH PIECE FOR SLIDING |
OSADA MASAHIKO
SAITO MIKIO
TAKAMATSU KEIZO
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