A spindle motor is provided comprising a fixed shaft capable of being fastened at either end to the base and cover of the disc drive. The hub which rotates around the disc drive is supported for rotation by a journal bearing and thrust bearing, with the thrust bearing grooved surfaces being defined in gaps immediately adjacent the ends of the journal bearing. A fluid recirculation path is provided through the rotating sleeve connecting the surfaces adjacent the thrust bearings, with the asymmetry which provides the fluid circulation either being inherently present due to tolerances in the bearing and groove design, or specifically provided by asymmetry in the bearing groove pattern. An asymmetric sealing system employs a pumping seal adjacent a radial end of the thrust plate near the base of the housing, and a shorter pumping seal defined adjacent a radial end of the thrust plate distal from the base.

 
Web www.patentalert.com

> Vertical guide unit and stage system with the same unit

~ 00383