Patent ID: 7178983

Claim:
A spindle motor comprising: a motor base having a thrust-bearing surface; a sleeve attached to the motor base and having an interior radial bearing surface and a thrust-bearing surface; a stator yoke disposed on the sleeve so as to surround the sleeve, and holding a coil thereon; a rotational shaft inserted in the sleeve, provided at one end thereof with a thrust plate having opposite thrust-bearing surfaces facing the respective thrust-bearing surfaces of the motor base and the sleeve, defining a dynamic air thrust bearing, and at the other end thereof with a hub having a radial bearing surface facing the radial-bearing surface of the sleeve, defining a dynamic air radial bearing; and a rotor magnet attached to a part facing the stator yoke of the hub; wherein the radial-bearing surface of the sleeve includes a lubricating oil holding mechanism to hold lubricating oil while the rotational shaft is rotating, and a gap not forming a bearing is formed between the circumference of the thrust plate and the inside surface of the sleeve to hold the lubricating oil while the rotational shaft is rotating.