| 摘要 |
PURPOSE:To miniaturize a position detector and to detect the position of a rotor honestly at low cost by arranging an optical reflector coaxially with a rotor gear and providing a detecting section having a photoluminescent subsection and a photoreceptive subsection opposite to the reflector. CONSTITUTION:A rotor 8 is formed by fixing to a shaft 5 rotor gears 1 and 4, an optical reflector 2 with nearly the same diameter as in the diameters 1 and 4 and a rotor magnet 3 in the axially laminated condition coaxially. On the other hand, a detecting section 7 having a photoluminescent subsection and photoreceptive subsection is provided to a circuit substrate 6 in the position opposite to the tooth-tip of a rotor gear 1. The beam injects from the photoluminescent subsection of the detecting section 7 to the optical reflecting section composed of the rotor gear 1 and the optical reflector 2. The beam reflects to the amount in proportion to the area of the opposite optical reflector 2 and injects to the photoreceptive subsection of the detecting section 7. The amount of this incident beam is converted into the electric signal, by which the position of the rotor 8 is detected.
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