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:
Dec. 07, 1999
Filed:
Dec. 09, 1998
Hideshi Fukutani, Yonago, JP;
Akihiko Wakitani, Yonago, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
Herringbone grooves are formed on an inner wall of a sleeve through which a motor shaft is inserted. Lubricating fluid is provided between a space between the shaft and the sleeve so as to form a relatively rotatable radial dynamic pressure bearing. A surface layer and the herringbone grooves on an inner wall of the sleeve, which are sliding regions with the motor shaft, have a different hardness from that of a base material of the sleeve. The hardness ratio of these two elements is set so that the shaft spins without wearing itself out as well as the sleeve surface layer. As a result, a highly reliable motor is achieved because the structure can maintain accurate whirling and suppress seizure due to abrasion powder between the shaft and the sleeve.