SLEEVE FOR HYDRODYNAMIC BEARING DEVICE, HYDRODYNAMIC BEARING DEVICE AND SPINDLE MOTOR USING THE SAME, AND METHOD FOR MANUFACTURING SLEEVE

摘要

PROBLEM TO BE SOLVED: To prevent the lowering of bearing rigidity of a sintered metal sleeve. SOLUTION: This sleeve includes an inner section 48a formed of metal powder for sintering and a resin for impregnation, and a surface deformation section 48b which covers a surface of the inner section 48a and is formed by shot blast process. Since the surface deformation section 48b is formed by the shot blast process, the number of pores formed between the metal powder for sintering near the surface can be reduced. In this way, a supporting pressure at a bearing portion can be prevented from being released out through the pores, and the bearing rigidity can be prevented from lowering. COPYRIGHT: (C)2007,JPO&INPIT