Patent ID: 6774521
Filing Date: 2004-08-10
Classification: H02K

Abstract:
A brushless DC motor comprising a rotor to which a permanent magnet is attached; and a stator having a plurality of slots, characterized in that:an effective opening angle of a magnetic pole of said rotor about an axis of rotation of said rotor is &thgr;2 and a salient area opening angle of the magnetic pole formed within the effective opening angle &thgr;2 is &thgr;3, the angles &thgr;2 and &thgr;3 being so related that the cogging torque generated by said effective opening angle &thgr;2 of the magnetic pole and the cogging torque generated by said salient area opening angle &thgr;3 of magnetic pole are mutually in antiphase, so as to cause the two torques to cancel each other.