Patent ID: 6196722
Filing Date: 2001-03-06
Classification: F16C

Abstract:
A hydrodynamic bearing, comprising:a stationary shaft fixed at one end thereof to a lower casing and having a flange member and an upper shaft portion adjacent to the other end thereof;a sleeve having a bearing bore in which the stationary shaft is inserted; anda thrust plate fixed to the sleeve and having a face opposed to a plane face of the flange member and an inner circumferential portion opposed to an outer circumferential portion of the upper shaft portion;wherein two sets of herringbone grooves are provided on the stationary shaft, each of the two sets of grooves including a distal zone and a proximal zone, wherein a length of said distal zone in an axial direction is longer than a length of said proximal zone in the axial direction;wherein an outer thrust hydrodynamic groove is provided in at least one of the opposed faces of the flange member and the thrust plate;wherein an outer diameter of the upper shaft portion and a diameter of the inner circumferential portion of the thrust plate are smaller than a diameter of the bearing bore of the sleeve;wherein the stationary shaft has a tapered portion provided on a side thereof opposite the herringbone grooves and across the flange member, the tapered portion having a progressively decreasing diameter as it extends away from the flange member;wherein the herringbone grooves and the outer thrust hydrodynamic groove are filled with a lubricant; andwherein an air channel is provided inside the stationary shaft with one end thereof opening on an outer circumferential portion of the stationary shaft intermediate the flange member and the herringbone grooves and with the other end thereof communicating with the exterior of the bearing.