Patent ID: 7498707

Claim:
An electric rotation machine comprising: a stator on which coils are wound by distributed winding; and a rotor which is supported to rotate, wherein: a gap is provided between the rotor and the stator; the rotor is equipped with a permanent magnet; poles of the rotor are arranged only with non-magnetic material between the adjoining poles so that the permanent magnet may be sandwiched by a pole piece and a rotor core; a pole width rate Pw obtained by dividing pole piece width Tp by pole pitch Tr at the outermost diameters of the adjoining poles of the rotor satisfies 0.67≦Pw≦0.71; and a ratio of a radius R 1 of the outermost periphery of the rotor and a radius R 2 of a circular portion of the pole piece satisfies 0.82 ⁢ < _ _ ⁢ R ⁢ ⁢ 2 R ⁢ ⁢ 1 ⁢ < _ _ ⁢ 0.9 .