Patent ID: 6801388
Filing Date: 2004-10-05
Classification: G11B,H02K

Abstract:
A spindle motor having a rotor and a stator for rotating the rotor, said rotor comprising:a shaft; a rotor housing formed integral with the shaft and configured to hold an object to be rotated; a rotor yoke formed integral with the rotor housing and made of magnetically permeable material; and a drive magnet secured to the rotor yoke, and said stator comprising: a stator housing; a first bearing held in the stator housing and supporting the shaft, allowing the shaft to rotate; a second bearing provided between the stator housing and the rotor housing, arranged concentric to the first bearing in a radial direction, and supporting the rotor, allowing the rotor to rotate; a stator yoke formed integral with the stator housing, constituting a part of a housing containing the rotor and the stator, and made of magnetically permeable material; and a drive coil mounted on the stator yoke and arranged in face-to-face relation with the drive magnet, wherein: the first bearing is a sintered metal bearing, and the second bearing is a ball bearing, and the sintered metal bearing is a dynamic-pressure fluid bearing.