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:
Aug. 21, 2001
Filed:
Jan. 09, 2001
Akihiro Kiuchi, Kanagawa, JP;
Manabu Ohori, Kanagawa, JP;
NSK Ltd., Tokyo, JP;
Abstract
In view of the fact that, when backup roll bearings which have been found satisfactory in the purity thereof in the sample evaluation through observations using a microscope are checked many times for the top surface layer portions of the raceway surfaces thereof according to an ultrasonic detecting method, on quite rare occasions, there can be found a bearing which contains one or more inclusions each having a size of as large as several hundreds &mgr;m, and such inclusions give rise to occurrence of a short-life bearing as a finished product, a range expressed by 2% Da depth×raceway surface is used as a test piece volume and the size of a non-metallic inclusion existing in the test piece volume is restricted to a length less than 500 &mgr;m, preferably, less than 100 &mgr;m. Here, the term “2% Da depth” means a depth up to 2% of a rolling element mean diameter from the surface of an inner or outer race of a bearing.