| 摘要 |
PURPOSE:To enable rotational frequency to be detected without increasing the outer diameter of a motor and without reducing torque, by providing the periphery of some section of a rotor magnet confronting a printed board for detecting the rotational frequency having zigzag pattern, with a rugged section. CONSTITUTION:A rotor magnet 14 is fixed on a shaft 4 via a rotor yoke 2. A stator is provided with a stator yoke 6 and stator coils 5. A printed board 9 for detecting rotational frequency has zigzag pattern, and the full periphery of a partial rotor magnet 14 confronting the printed board 9 is provided with convex sections and concave sections. The phase on the convex sections of the pole N sections is different from the phase on the convex sections of the pole S sections by an angle for one half a cycle on the zigzag pattern of the printed board 9. |
