Hydrodynamic-pressure bearing device and motor provided with the hydrodynamic-pressure bearing device

US6361214B1 · kind B1 · utility

Assignee

• NIDEC CORPORATION · JP

Inventor

• Yoshikazu Ichiyama · Kyoto, JP

Key dates

• Filing date: Jul 28, 2000
• Grant date: Mar 26, 2002
• Expiry date: Jul 28, 2020

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16C2370/12
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

Spindle motor hydrodynamic pressure bearing device having upper and lower radial bearing portions axially separated by an air space, established in the micro-gap between the outer circumferential surface of the motor shaft and the inner circumferential surface of the motor sleeve element, and upper and lower thrust bearing portions established on either side of a thrust plate flange at the lower end of the shaft. A micro-gap established between the thrust plate and an opposing base surface of a recess in the sleeve element accommodating the thrust plate is continuous with the lower radial bearing micro-gap. Lubricating oil in the micro-gaps is therein retained continuously between the lower radial bearing and the upper thrust bearing. The lower radial bearing generates hydrodynamic pressure acting axially outward (toward the upper thrust bearing), and the upper thrust bearing generates hydrodynamic pressure acting radially inward (toward the lower radial bearing). Consequently, a high hydrodynamic pressure area develops in the vicinity of boundary between the lower radial and upper thrust bearings, which by cooperation of the bearings generates supporting force bearing axial and ra…