Patent ID: 7281852
Filing Date: 2007-10-16
Classification: F16C

Abstract:
1. A fluid dynamic bearing system comprising a fixed shaft, a sleeve rotatable around the shaft, the shaft supporting first and second thrust plates axially spaced apart along the shaft, the sleeve having a first surface and cooperating with a surface of the shaft to define a journal bearing and the sleeve also having a radially extending surface cooperating with a radially extending surface of the first thrust plate and the second thrust plate to define a first thrust bearing and a second thrust bearing, the sleeve including a second surface facing a second thrust plate surface, the second thrust plate surface extended from the radially extending surfaces of the first and second thrust plates to establish a first pumping seal at a first end of a gap of the fluid dynamic bearing pumping toward a second pumping seal at an opposite second end of the fluid dynamic bearing gap, wherein the first pumping seal is relatively stronger than the second pumping seal as provided by a groove pattern on at least one of the sleeve second surface and the thrust plate second surface at the first gap end.