Motor with recess for index position detection

摘要

The invention relates to a motor, and more particularly to a motor having means for detecting an index position. A rotor yoke of the motor is provided with a recess having a width greater than the width of each pole of a rotating magnet. Substantially the whole of one pole of the rotating magnet and a part of another pole adjacent to the one pole on the downstream side in terms of rotation of a rotor are exposed to the recess. The magnetic flux from the magnet exposed to the recess is detected by a Hall element disposed in opposition to the outer circumference of the rotor, thereby specifying the index position.