Patent ID: 7148592

Claim:
A stepping motor comprising: a first magnet and a second magnet, each of which is formed in a ring shape, in each of which at least one surface perpendicular to a central axis thereof is divided in a peripheral direction and alternately plane-magnetized in different poles, the second magnet being located at a position concentric with the first magnet in a direction along which the central axes thereof extend; a first stator including a plurality of magnetic pole teeth which are opposed to the magnetized surface of the first magnet and extend in a radial direction; a second stator including a plurality of magnetic pole teeth which are opposed to the magnetized surface of the second magnet and extend in the radial direction; a rotor which is made of a soft magnetic material for passage of magnetic fluxes of a magnetic circuit and includes a shaft portion held to be rotatable and a disk portion having a surface perpendicular to the shaft portion; a first coil which is fixed to the first stator and excites the first stator and the disk portion of the rotor to which the first magnet is fixed on one side; and a second coil which is fixed to the second stator and excites the second stator and the disk portion of the rotor to which the second magnet is fixed on the other side wherein a first flange portion which protrudes from the disk portion to the first stator is located inside the first coil fixed to the first stator, the first magnet is located outside the first coil, and the disk portion of the rotor is located on an opposite side of the first coil which is in contact with the first stator, and a second flange portion which protrudes from the disk portion to the second stator is located inside the second coil fixed to the second stator, the second magnet is located outside the second coil, and the disk portion of the rotor is located on an opposite side of the second coil which is in contact with the second stator.