Patent ID: 7259488

Claim:
A rotary electric machine comprising a stator having a plurality of coils arranged in a substantially circular form around an axis and a rotor rotatable about said axis relative to said stator, wherein said rotor comprises a rotor yoke facing said coils and having a gap in axial direction, wherein said rotor yoke is made of a circular disc of a ferromagnetic material, and wherein a corrugated region having depressed portions and raised portions alternating with each other is formed in a circumferential direction of said rotor yoke, said depressed portions on a first surface of the corrugated portions formed in the portions corresponding to said raised portions on a second surface of the corrugated portions and said raised portions on said first surface of the corrugated portions formed in the portions corresponding to said depressed portions on said second surface of the corrugated portions, and magnets are arranged in said depressed portions on both surfaces of the corrugated portions, said raised portions are made of said ferromagnetic material and wherein out of all depressed portions, in those depressed portions on a surface side of said rotor yoke facing said coils, N-pole magnets and S-pole magnets are arranged alternately.