| 摘要 |
PURPOSE: To simplify the machining and assembling works by an arrangement wherein a protective case holding a light projecting/receiving cell moves as a shaft fixed with a rotary slit plate moves. CONSTITUTION: The output shaft 4 of a motor drives the output gear 5 of a reduction gear through a worm drive shaft 41. A pulse generator is carried on the output shaft 4 and a track disc 1 thereof is fixed onto the rotor shaft 4 through a projecting boss 2 additionally formed in the axial direction and a protective case 3 is supported by the boss 2. A light transmitter 6 and a light receiver 7 are fixed to the protective case 3 and coupled optically through a shutter grid 11 in the track disc 1. The protective case 3 is locked to the output shaft by the outer guide ring 21 of the boss 2 through a guide shoulder part 31. Since the entire pulse generator moves as the output shaft moves in the axial direction, positional relationship of the track disc 1, the light transmitter 6 and the light receiver 7 is kept intact. |
