Patent ID: 6870291

Claim:
A stepping motor comprising: a stator unit comprising a pair of stator sub-assemblies integrally attached to each other in a back to back manner, each of the stator sub-assemblies including: a plurality of pole teeth formed at an inner circumference of the sub-assembly and housing a coil inside thereof; and a rotor unit rotatably disposed with a small gap from the plurality of pole teeth and having multiple magnetic poles formed on a circumference thereof, the multiple magnetic poles being formed by magnetizing the rotor unit alternatively with an S pole and an N pole in a circumferential direction, wherein at least one first pair of the S pole and the N pole has the width of the at least one first paired S pole set to be smaller than the width of the at least one first paired N pole, and at least one second pair of the S pole and the N pole has the width of the at least one second paired S pole set to be larger than the width of the at least one second paired N pole.