Patent ID: 8324779

Claim:
A motor comprising: a rotor including: a rotor core; a plurality of magnets arranged along the circumferential direction of the rotor core, the magnets functioning as first magnetic poles; and a plurality of salient poles integrally formed with the rotor core, each salient pole being located between a circumferentially adjacent pair of the magnets with gaps in between, and functioning as a second magnetic pole different from the first magnetic poles; and a stator having a plurality of teeth that are opposed to the magnets and the salient poles of the rotor in the radial direction and are arranged at equal intervals in the circumferential direction, wherein a first auxiliary groove is formed in a surface of each salient pole that is opposed to the teeth, the first auxiliary groove having first and second side surfaces facing each other in the circumferential direction, the first side surface being closer to a circumferential center line of the salient pole than the second side surface, and wherein, when the angle from the circumferential center line to the first side surface of each salient pole about the axis of the rotor is represented by KC1, the opening angle between the circumferential ends of the distal end of each tooth about the axis is represented by KA, and the opening angle between the circumferential ends of each salient pole about the axis is represented by KB, the following expression is satisfied: KC 1 =KA−KB/ 2.