The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 16, 2003
Filed:
Feb. 13, 2002
Hironobu Ishikawa, Aichi, JP;
Tetsuji Yogo, Aichi, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A ceramic dynamic-pressure bearing which is not prone to wear or a like problem associated with starting, stopping, or a like operation mode and which can realize smooth rotation. A dynamic-pressure gap is formed between a first member and a second member , which undergo relative rotation about a predetermined axis of rotation. The relative rotation of the first member and the second member generate fluid dynamic-pressure in the dynamic-pressure gap . At least a portion of one or both of the first member and the second member includes a polished surface (a dynamic-pressure gap definition surface) formed of alumina ceramic facing the dynamic-pressure gap , and the alumina ceramic, which forms the dynamic-pressure gap definition surface finished by polishing, is adjusted to have an apparent density of 3.5-3.9 g/cm . Also disclosed is a motor, hard disk drive and polygon scanner containing the bearing.