PM type stepping motor

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PROBLEM TO BE SOLVED : To provide a stepping motor having characteristics equivalent to or better than the conventional ones, even if a ferrite magnet of low cost is used without using a rare earth magnet of an expensive material.SOLUTION : A PM type stepping motor includes : a columnar rotor 300 which has a columnar shape and in which a plurality of magnetic poles are arranged in the circumferential direction on the outer peripheral surface; a stator yoke 200 which includes a cylindrical outer peripheral part, and an inner peripheral part having a plurality of first pole teeth which house a rotor inside and extend in one direction of the axial direction, and a plurality of second pole teeth engaging with the plurality of these first pole teeth while being separated by a gap; and bearings 501, 502 which hold the rotor 302 with respect to this stator yoke 200 in a freely rotatable state. The ratio of the outer diameter d of the rotor 300 to the outer diameter D of the stator yoke satisfies a relation of d/D>0.6.SELECTED DRAWING : Figure 1