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:
May. 08, 2007
Filed:
Mar. 07, 2002
Hironobu Ishikawa, Aichi, JP;
Atsutoshi Sugiyama, Gifu, JP;
Hironobu Ishikawa, Aichi, JP;
Atsutoshi Sugiyama, Gifu, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A ceramic dynamic-pressure bearing includes a first memberhaving a cylindrical outer surface and a second memberhaving a cylindrical reception hole formed therein. The first memberis inserted into the reception hole. A radial dynamic-pressure gap is formed between the inner surface of the reception hole of the second memberand the outer circumferential surface of the first memberThe first memberand the second memberare formed of an alumina ceramic which contains an Al component in an amount of 90–99.5% by mass as reduced to AlOand an oxide-type sintering aid component in an amount of 0.5–10% by mass as reduced to an oxide thereof. The thrust dynamic-pressure gap definition surface of the second member which faces the thrust plate has a flatness of not greater than 3 μm or the thrust dynamic-pressure gap definition surface of the thrust plate which faces the second member has a flatness of not greater than 3 μm. Also disclosed is a hard disk drive having a motor including a motor rotation output section having the ceramic dynamic-pressure bearing.