Patent ID: 7573260

Claim:
A magnetic rotor comprising: a holder, through which a rotatable shaft is received; a positioner that is made of a magnetic material and is fitted into at least one of an outer peripheral wall of the rotatable shaft and an inner peripheral wall of the holder to position the holder relative to the rotatable shaft in a circumferential direction; and an annular magnet that is fixed to the holder and surrounds the rotatable shaft, wherein: the annular magnet has two magnetic poles of different polarities, which are magnetized in a magnetization direction that coincides with a radial direction of the annular magnet; and the positioner is displaced around a rotational axis of the rotatable shaft from the magnetization direction of the annular magnet by about 90 degrees in the circumferential direction, wherein: the rotatable shaft has a groove in the outer peripheral wall of the rotatable shaft; the holder has a groove in the inner peripheral wall of the holder; and the positioner is fitted into the groove of the rotatable shaft and the groove of the holder.