Patent ID: 6218753
Filing Date: 2001-04-17
Classification: H02K

Abstract:
A motor comprising:(a) a stator core comprising a plurality of teeth and a yoke that links the teeth;(b) coils wound on the teeth; and(c) a rotor with at least one interior permanent magnet and an axis of rotation, wherein said rotor comprises:(c-1) a plurality of rotor cores formed from stacked rotor-core-sheets made of electromagnetic steel plates;(c-2) an interior permanent magnet buried within said rotor;(c-3) a non-magnetic-section located along the outer circumference of the rotor provided in contact with at least one longitudinal end of said permanent magnet; and(c-4) an angle "".theta."" made by a width of the non-magnetic section along the outer circumference of the rotor which is measured radially around the axis of rotation from a pole boundary to the distal end of the non-magnetic section,wherein the rotor is formed by stacking a plurality of rotor cores together, and the size of the angle "".theta."" is varied between adjacent rotor cores along an axial direction which is parallel to the axis of rotation.