Patent ID: 7847453

Claim:
A bearingless step motor, comprising: a stator including stator cores having winding portions; a rotor including a rotating shaft and rotor cores, the rotor being configured to rotate by a magnetic interaction between the rotor cores and the stator cores; a first permanent magnet mounted to the rotor, the first permanent magnet being formed in a ring shape so as to surround the rotating shaft; and a plurality of second permanent magnets mounted to the stator; wherein N-S poles of the first permanent magnet are arranged in an axial direction of the rotating shaft and N-S poles of the second permanent magnets are arranged in the same direction of the N-S poles of the first permanent magnet such that the first permanent magnet and the second permanent magnets generate a repulsive force therebetween, wherein at least one of the first permanent magnet and the plurality of second permanent magnets is configured such that a width becomes narrower as it proceeds to a gap between the rotor and the stator.