| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a fluid dynamic bearing unit capable of retaining high angle stiffness of the bearing and preventing an oil film of the bearing from breaking by discharging air in the bearing. <P>SOLUTION: A circulating passage of a lubricant is formed by a connection hole and a radial hydrodynamic pressure generation groove in the fluid dynamic bearing unit, and a first thrust bearing surface is prepared at a position in contact with the circulation passage. A first thrust hydrodynamic pressure generation groove formed on the first thrust bearing surface is a spiral groove with a pumping mechanism in the pattern. Bubbles in the bearing are smoothly discharged with lubricant circulation caused by an asymmetrical radial hydrodynamic pressure generation groove. Generated pressure on the thrust bearing surface during bearing rotation is a pressure distribution where a high-pressure zone is widened. <P>COPYRIGHT: (C)2009,JPO&INPIT |
