PG SIGNAL DETECTING DEVICE FOR ROTARY HEAD CYLINDER

摘要

PURPOSE:To obtain a PG signal having a good S/N ratio. CONSTITUTION:A notched part 14A is provided on the outer periphery side of one magnetic pole part 14 of the rotor magnet 11 of a flat brushless motor, and also a projecting part 14B is provided on the inner periphery side thereof. Two PG coils 15 and 16 which are normally and reversely wound in a linearly symmetric form are provided at a position deviated from the magnetizing cycle of the rotor magnet on the stator base plate of the flat brushless motor by an electrical angle 180 deg. so that magnetic fluxes may be intersected.