| 摘要 |
PURPOSE:To reduce the size and to increase the resolution of a motor by integrally providing pulse generating means on the outer periphery of a rotary armature or on the side face near the outer periphery, and providing generated pulse detecting means at the stationary part of a yoke or housing. CONSTITUTION:An armature 5 and a commutator 6 are secured on a rotational shaft 4 which is supported to bearings 2, 3 mounted in a housing 1. A yoke 7 and a yoke 9 for securing a plurality of permanent magnets 8 are secured relatively to the coil portion of the armature in a housing 1. A thin film metal reflecting surface 11 is circularly formed on the side face 10 near the outer periphery of the armature 5, and light absorption thin films 12 of equal pitch and fine linear shape are formed radially thereon. A light emitting element 13 and a photoreceptor 14 are secured corresponding to the surface 11 by a holder 15 in the housing 1. When the armature 5 is energized through a brush 18 contacted with the outer periphery of the commutator 6, the armature 5 starts rotating, the light projected from the element 13 reaches the photoreceptor 14 to become pulse shape, thereby providing a pulse number proportional to the rotating angle of the armature 5. |
