| 摘要 |
PROBLEM TO BE SOLVED: To provide a stepping motor whose drive frequency can be increased without accompanying reduction in rotational torque. SOLUTION: The stepping motor includes a two-pole rotor 53 and a stator provided with a yoke and two coils 55 provided so that they are magnetically coupled with the yoke 52. The yoke has first to third magnetic poles X to Z that form an annular face opposed to the outer circumferential surface of the rotor and are magnetically separated by first to third magnetically separating portions 52x to 52z. The annular face is formed of: first to fourth approaching portions 62a to 62d that are positioned at 90 degrees and approach the rotor; and first to fourth receding portions 62e to 62h that are provided between adjacent approaching portions, respectively, positioned at 90 degrees, and provided so that they are shifted from the approaching portions at 45 degrees. The individual receding portions 62e to 62h are positioned farther from the rotor 53 than the individual approaching portions 62a to 62d. Thus, a stepping motor in which a step is provided in magnetic potential energy at 45 degrees and the angle of one step is 90 degrees is obtained. COPYRIGHT: (C)2006,JPO&NCIPI
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