Patent ID: 7443068

Claim:
A spindle motor comprising: a rotor magnet having a circular shape and including a plurality of pairs of magnetic poles polarized in a radial direction, the pairs of magnetic poles are arranged along a circumferential direction of the rotor magnet; a rotor hub having a circular surface, the rotor hub supports the rotor magnet and is rotatable around an axis of the circular shape of the rotor magnet; a stator including a circumferential surface radially opposing a circumferential surface of the rotor magnet; and a bearing rotatably supporting the rotor hub; wherein the circular surface opposes one axial end surface of the rotor magnet and has an abutting portion that abuts against the rotor magnet at or near a bounding portion of the magnetic poles; a gap extends in a radially-inward and radially outward directions from the abutting portion; and at least a portion of the rotor hub where the circular surface is provided is made of a ferromagnetic material.