<p>A yoke insertion section (28) is formed in an axially projecting manner on a brush holder stay (21). A magnet (8) and a magnet holder (9) are installed on a yoke inner peripheral surface (7a).A rib (30) is formed on the outer peripheral surface of the yoke insertion section (28), and the brush holder stay (21) is fitted into a yoke (7) with slight interference. A stay pressing claw (36) is formed at the magnet holder (9). The yoke insertion section (28) is held between the stay pressing claw (36) and the yoke inner peripheral surface (7a), and the brush holder stay (21) is fixed in the yoke (7). A flat surface (37) is formed on the inner peripheral surface of the yoke insertion section (28), and the stay pressing claw (36) comes into contact with the flat surface (37).</p>
