| 摘要 |
PROBLEM TO BE SOLVED: To reduce cogging torque remarkably in a three-phase permanent magnet type synchronous electric motor.SOLUTION: When the number of magnetic poles of a stator 3 is P and the number of grooves of a stator 2 is N, fraction 2N/3P is not an integer. In the three-phase permanent magnet type synchronous electric motor, the tooth width in the circumferential direction of a tooth 5 of the stator 2 facing the surface of the magnetic pole of the stator 3 via a cavity is made almost 1/2 of a groove pitch of the stator 2. Moreover, in the three-phase permanent magnet type synchronous electric motor of an outer rotor type, the cross section in the radial direction of the tooth 5 of the rotor 2 is made almost equal from the tooth tip to the tooth root or the tooth root is made larger in comparison with the tooth tip, thereby enabling winding unit having a coil would therearound to be attached from the tooth tip. |
