To solve a problem that a pigtail buried in a brush eventually touches a commutator when the brush wears away to cause cracking or chipping of the brush and other component is damaged during rotation to cause a trouble in recycling.
The brush pressing end of a spring 15 is shifted to the commutator 5 side as a brush 6 wears away. When the clearance between a pigtail 16 and a commutator 5 becomes α, the brush pressing end of the spring 15 abuts against the wall part 17 and the pressing force of the spring 15 against the brush 6 is substantially eliminated. Consequently, contact resistance of the brush 6 and the commutator 5 increases to cause incomplete conduction and the lifetime expires. Since the pigtail 16 does not touch the commutator 5 even if the lifetime expires, the brush 5 is protected against cracking or chipping, and damage of each component in the starter motor is avoided thus promoting recycling.
JPS6066273 | [Title of the device] Brush device |