Patent ID: 7923880

Claim:
A single phase stepping motor comprising: a stator; and a rotor disposed to surround the stator, wherein the stator includes: first and second annular stator yokes, which are disposed opposite to each other and have a plurality of pole teeth formed along a circumference thereof; and an annular stator coil disposed between the first and second stator yokes, wherein the rotor includes: a ring magnet, which is disposed to surround the first and second stator yokes, and has a plurality of magnetic poles formed along a circumference of the rotor; and a shaft disposed at a center position of the ring magnet, wherein the pole teeth and the ring magnet are positioned such that a gap is formed between each of the pole teeth and the opposing magnetic pole of the ring magnet, and wherein each of the gaps has a first half side from a center position in a width dimension of each of the pole teeth that is uniform and a second half side that is non-uniform in a predetermined direction.