US Patent 8179016 Motor and compressor

A motor includes a rotating shaft, a rotor fixed to the rotating shaft and first and second stators facing each other on opposite axial sides of the rotor with a gap in between. Each of the first and second stators includes a back yoke, teeth circumferentially arranged on a gap side of a respective one of the back yokes and coils wound around the teeth. The back yoke of the first stator has a portion facing an end face of the rotating shaft, and the back yoke of the second stator has a shaft hole through which the rotating shaft passes. The thickness Ty1 of the back yoke of the first stator is set smaller than the thickness Ty12 of the back yoke of the second stator.