Patent ID: 7714471

Claim:
A motor comprising: a stator; a rotor being rotatable relative to the stator and having a rotation axis; and a bias magnet and a magnetic-material member magnetically interacting with each other and being provided for enabling the stator and the rotor to magnetically attract each other, the bias magnet having a shape of a ring and being coaxial with the rotation axis, the bias magnet having an inner circumference and an outer circumference, the inner circumference and the outer circumference having a common center, the bias magnet and the magnetic-material member being axially opposed to and axially spaced from each other; wherein the bias magnet has a plurality of N and S poles alternately arranged along a circumferential direction thereof, and at least one of boundaries between the N and S poles extend on a straight line off of the common center as viewed in an axial direction of the bias magnet.