简介 |
PROBLEM TO BE SOLVED : To provide a PM type stepping motor having a large torque or a low power consumption using a permanent magnet.
SOLUTION : The PM type stepping motor comprises a rotor having an outer circumferential surface arranged alternately with N poles and S poles of a cylindrical permanent magnet, a plurality of yokes consisting of yoke bodies having a trapezoidal shape facing the permanent magnet vertically and alternately through a gap where the bottom part of the trapezoidal shape is continuous to overlapping pole teeth along the axial direction of the rotor, and an exciting coil for the pole teeth provided in each yoke. The permanent magnet is a high magnetism pole anisotropic rare earth bond magnet or a low magnetism pole anisotropic rare earth sintered magnet and the width of a bridge part connecting the pole tooth and the yoke body is set narrower than the width at the bottom part of pole tooth in trapezoidal shape. |