Patent ID: 8179016

Claim:
A motor comprising: a rotating shaft; a single rotor fixed to the rotating shaft; and first and second stators arranged on opposite axial sides of the rotor with the first and second stators facing each other through air gaps on the opposite axial sides of the rotor, each of the first and second stators including a back yoke, circumferentially arranged teeth located on an air gap side of a respective one of the back yokes, and coils wound around the teeth, the back yoke of the first stator having a portion facing an end face of the rotating shaft, the back yoke of the second stator having a shaft hole with the rotating shaft passing therethrough, the back yoke of the first stator having a through hole smaller than an outer diameter of the rotating shaft, the rotating shaft not being received in the through hole of the back yoke of the first stator, and the back yoke of the first stator having a thickness Ty 1 smaller than a thickness Ty 2 of the back yoke of the second stator, with the entire back yokes of the first and second stators having respective generally uniform axial thicknesses Ty 1 and Ty 2 .