| 摘要 |
<p>A step-shaped brush (4) having a step section (4a), that: is impelled by a spring (5); comes in contact with the outer peripheral surface of a commutator (3) that rotates centered around a rotation axis (X); and slides. Initially, a tip section of the brush (4) comes in contact with a brush sliding surface (A) of the commutator (3). As the brush (4) wears as a result of changes over time, the step section (4a) comes in contact with the commutator (3) and the point of contact displaces, in accordance with the wear, from the brush sliding surface (A) to an unused brush sliding surface (B).</p> |
