Fluid dynamic-pressure bearing device and spindle motor
US7578621B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 2007 |
| Grant date | Aug 25, 2009 |
| Priority date | — |
| Expiry date | Oct 29, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K7/085
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A fluid dynamic-pressure bearing includes a rotatable shaft, a hub, a fixed portion, and a lubricating liquid. The hub includes a hub thrust bearing surface extending from the shaft outwardly in a radial direction and an annular surface. The fixed portion includes a fixed-portion upper thrust bearing surface facing the hub thrust surface and a flange surface facing the annular surface. The hub thrust bearing surface, the fixed-portion upper thrust bearing surface, and the lubricating liquid arranged therebetween form together an upper thrust dynamic-pressure bearing. The annular surface and the flange surface define an annular gap therebetween. An axial dimension of the annular gap is larger than a total of an axial dimension of an upper thrust gap between the hub thrust bearing surface and the fixed-portion upper thrust bearing surface and an average depth of upper thrust dynamic-pressure generating grooves of the upper thrust dynamic-pressure bearing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.