Matsushita Electric Industrial Co., Ltd.

Quantum Corporation

Shinichi Minakuchi

Michael R Hatch

Yan Zang

Nobuhiro Yoshino

A self-contained hydrodynamic bearing unit with improved sealing and performance is disclosed. Centrifugal capillary seals are angularly defined between an outwardly tapered outer surface of a top screw and an inwardly tapered inner surface of an annular clamp ring at the top of the bearing unit as well as between an outwardly tapered outer surface of a seal plate and an inwardly tapered inner surface of an annular clamp ring at the bottom of the bearing unit. During operation, bearing lubricant is pumped away from the seal opening and toward the bearings by centrifugal force at the seals, providing dynamic sealing. When the bearing unit is not rotating, capillary forces retain the lubricant within the seal, preventing the lubricant from leaking. The tapered configuration of the seals also shortens the vertical seal length for a given effective seal length, thereby maximizing the journal bearing length/span and improving dynamic performance of the bearing unit.

Hydrodynamic bearing unit

A motor having a dynamic-pressure type bearing device includes a cylindrical sleeve fixedly secured to a base, a shaft rotatably inserted into a hollow of the cylindrical sleeve, a hub fixedly secured to an end portion of the shaft, a ring-like rotor magnet fixedly secured to the hub, and an armature fixedly secured onto the base to be in opposed relation to the rotor magnet so as to constitute a motor driving device. Further, the motor has a disc-like plate coaxially and fixedly secured to an end portion of the shaft to have a diameter of the disc-like plate greater than a diameter of the shaft and a plate disposed in opposed relation to a surface of the disc-like plate. The bearing device includes a radial dynamic-pressure groove assembly having a predetermined groove configuration to generate a radial dynamic pressure in a radial direction of the shaft and an axial dynamic-pressure groove assembly having a predetermined groove configuration to generate an axial dynamic pressure in an axial direction of the shaft. The radial dynamic-pressure groove assembly is formed in at least one of an outer circumferential surface of the shaft and an inner surface of the cylindrical sleeve which face each other and the axial dynamic-pressure groove assembly is formed in at least one of the surface of the disc-like plate and a surface of the plate disposed in opposed relation to the surface of the disc-like plate.

Growing community of inventors

Iyo, Japan

Shinichi Minakuchi