Hydrodynamic bearing arrangement having a structure permitting the removal of entrapped air

摘要

Air which would otherwise be entrapped in an O-ring seal groove in a hydrodynamic bearing arrangement is removable from the seal groove by providing at least one passage between the seal groove and an adjacent thrust plate recess. The air is removed from the seal groove though the passages by drawing a vacuum at a lower end of the bearing arrangement. Preferably, the passages are formed, at least in part, by grooves defined in the upper surface of a land formed between the seal groove and the thrust plate recess. A method of forming the grooves is also disclosed.