Patent ID: 8058762

Claim:
A rotor comprising: a plurality of magnets, each having a pole face, disposed annularly with polarities being symmetric around a predetermined axis; a plurality of magnetic members; other magnetic members provided to cover said pole face of said magnets magnetically independently and individually on one side of said axis; and a magnetic plate covering said pole face and said magnetic members on said one side, said magnetic plate having opening slits extending from positions close to said axis to farther positions between said magnetic members and said magnets as viewed along said axis, divisions of said magnetic plate divided by said slits in a circumferential direction around said axis that cover said pole face serving as said other magnetic members, said other magnetic members being connected to divisions of said magnetic plate divided by said slits in the circumferential direction around said axis that cover said magnetic members with thin portions interposed therebetween at least on the side of one ends of said slits, an inductance along an axis passing through a first type of said magnets having said pole face exhibiting a first polarity with respect to said one side of said axis and a second type of said magnets having said pole face exhibiting a second polarity with respect to said one side being smaller than an inductance along an axis bypassing said first and second types of said magnets perpendicular to the axis passing through said magnets, and said magnetic members being provided at least between said first type of said magnets and said second type of said magnets.