To provide technique for rationally detecting abrasion of a brush in a power tool including a motor having a brush.
A detection circuit 210 for detecting the abrasion state of two or more brushes 145a to 145d includes a first terminal part T1A to T1D and a second terminal part T2A to T2D provided on every brush. wherein when one brush is brought into sliding contact with a commutator 137 to wear away and reach a predetermined length, the first terminal part and the second terminal part provided corresponding to the brush come into contact with each other. In at least one of the two or more brushes, when the first terminal part and the second terminal part come into contact with each other, the detection circuit 210 is energized, whereby a predetermined brush abrasion state is detected.
COPYRIGHT: (C)2006,JPO&NCIPI
Shuji Yoshikawa
Junichi Nishimi
| JP57078353A | ||||
| JP7245919A |
Toshiyuki Ikeda