Parallel capillary seal for a disk drive

摘要

A fluid dynamic bearing includes a shaft rotating within a sleeve. The shaft and sleeve are supported for relative rotation by fluid in the gap between the shaft and sleeve. To prevent fluid from leaking out of the fluid dynamic bearing into the surrounding atmosphere, one end of the fluid is defined by a capillary seal. The seal is defined between the hub which rotates to establish rotation of the discs, and a facing surface of the sleeve. The surface of the hub and surface of the sleeve are in relative rotation, and diverge from one another in the region where the capillary seal is to be established. The gap which is incorporated in the capillary seal is in airway communication with the gap between the shaft and the sleeve; but the capillary seal is now defined by a radially outer surface of the sleeve and is substantially parallel to the gap between the shaft and the sleeve. The capillary seal is preferably substantially parallel to but radially spaced from the region where one of the dual journal bearing groove sets is defined. The grooves on the shaft that define the dual journal bearings may be located so that they are distributed as well as possible on either side of the center of gravity of the system.