Patent ID: 6951422
Filing Date: 2005-10-04
Classification: F16C,G11B,H02K

Abstract:
1. A spindle motor for use in a disk drive comprising: a shaft having a straight larger diameter section and a straight smaller diameter section with a step formed therebetween; a bearing sleeve having a central cylindrical opening, said shaft being inserted into said central cylindrical opening; a bearing gap formed between said shaft and said bearing sleeve, said bearing gap being filled with lubricating fluid; and a thrust plate fixedly mounted on said shaft in the area of said step such that an upper side of said thrust plate is placed adjacently to said larger diameter section and a lower side of said thrust plate is placed adjacently to said smaller diameter section; wherein a first radial hydrodynamic bearing is formed within said larger diameter section of the shaft, wherein a second radial hydrodynamic bearing is formed within said smaller diameter section of the shaft, wherein said first radial hydrodynamic bearing is located above said thrust plate and wherein said second radial hydrodynamic bearing is located below said thrust plate.