Patent ID: 7466055

Claim:
A permanent-magnet synchronous motor comprising: a toroidal stator core having an outer periphery, a plurality of internal radial teeth, and Z slots, each slot separating a pair of teeth, and a coil arranged on the stator core, wherein Z is a natural number; a rotor having permanent magnets with 2 p poles, the rotor being disposed within the toroidal stator core, wherein p is a natural number; and a pressurizing part that applies a local extreme pressure to the outer periphery of the toroidal stator core, radially inwardly, at each of N locations, wherein N is any one of positive values of values chosen from values calculated from N=p, N=±2 p−Z(i 1 ), and N=Z(i 1 )±2 p, i 1 is an integer and at least 0, and the N locations are chosen so that each local extreme pressure applied is aligned with a center line of at least one of the radial teeth.