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Title:
ROLLING BEARING
Document Type and Number:
Japanese Patent JP2009191942
Kind Code:
A
Abstract:

To provide a rolling bearing capable of preventing indentation start point type early exfoliation by maintaining a low tangential force acting on a rolling contact part without increasing the amount of residual austenite on the surface regarding any member.

Each ball 6 is formed by nitriding or carbonitriding treatment so that the nitrogen concentration of a rolling surface is 0.2-2.0 mass% and that the area rate of an Si-Mn-based nitride which is a nitride containing Si and Mn is 1-20%. The grain diameter of a nonmetallic inclusion included in a metallic material that constitutes at least one member out of an outer ring 3, an inner ring 5 and each ball 6 is restrained. Specifically, in regard to the larger dimensions of a maximum inclusion out of the dimensions of an oxide-based maximum inclusion and the dimensions of TiN-based maximum inclusion in an area 30,000 mm2 estimated by a method of extreme value statistics, when a square root (Dd) of the product of a length D and a breadth d is set as estimated inclusion dimensions (areamax), (areamax)30 m is to be satisfied.


Inventors:
UEDA TORU
Application Number:
JP2008033200A
Publication Date:
August 27, 2009
Filing Date:
February 14, 2008
Export Citation:
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Assignee:
NSK LTD
International Classes:
F16C33/62; C21D1/06; C21D9/36; C21D9/40; C22C38/00; C22C38/38; F16C33/32; F16C33/34; F16C33/64
Domestic Patent References:
JP2006063356A2006-03-09
JP2006308019A2006-11-09
JP2007314811A2007-12-06
JP2006063402A2006-03-09
Foreign References:
WO2007135929A12007-11-29
Attorney, Agent or Firm:
Takeo Koyama
Takashi Daejeon
Masaki Muto
Go Shino
Kinzo Koyama