Patent ID: 6867526

Claim:
A brushless DC motor comprising a rotor attached with permanent magnets at equal pitches in a circumferential direction, the rotor comprising: a bridge connecting a portion on an inner side of the permanent magnet and a portion on an outer side thereof, and a rib disposed between an end portion in the circumferential direction of an effective magnetic pole opening angle of the permanent magnet and a front end of the bridge along a side edge thereof; and a stator comprising a plurality of teeth aligned at equal pitches in the circumferential direction, and a plurality of slots defined between adjacent teeth, wherein an opening angle θr produced by viewing the bridge from a center of the rotor, is substantially equal to a tooth width opening angle θth in the stator, wherein the tooth width opening angle θth includes a circumferentially extending tip on each of the plurality of teeth, and wherein a rib opening angle θd is smaller than a teeth interval opening angle θop.