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:
Oct. 23, 2007
Filed:
Sep. 02, 2005
Takeyoshi Yamamoto, Niihama, JP;
Yoshihiro Ashizaki, Hirakata, JP;
Takeyoshi Yamamoto, Niihama, JP;
Yoshihiro Ashizaki, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An object of the present invention to provide a hydrodynamic bearing device and a motor having a high performance and reliability which prevents deterioration in a temperature property due to a difference in coefficients of linear expansion of a sleeve and a shaft and prevents abrasion of bearing surfaces of both the sleeve and the shaft. The sleeve is formed of a copper metal material or an iron metal material and is treated with electroless nickel plating at least on the surface which opposes the shaft. The shaft includes 0.2% by weight C, 0.3% by weight Si, 8% by weight Mn, 0.2% by weight S, 2.5% by weight Ni, and 14% by weight Cr, and a main component of the shaft is a manganese alloy steel including Fe.