Title:
ROLLING BEARING
Document Type and Number:
WIPO Patent Application WO/2021/059975
Kind Code:
A1
Abstract:
A rolling bearing comprising an inner race, an outer race, and a rolling element that are formed using steel. The rolling bearing is a tapered roller bearing, a cylindrical roller bearing, or a deep-groove ball bearing and has a quench-hardened layer in at least the inner race track surface of the inner race, the outer race track surface of the outer race, or the rolling surface of the rolling element. The proportion of the total area of martensite crystal grains in the quench-hardened layer is at least 70%. The martensite crystal grains are divided into a first group and a second group. The average grain diameter of the martensite crystal grains in the first group is no more than 0.97 μm. The hardness of the quench-hardened layer at the surface of the quench-hardened layer located at the center of the rolling surface in the axial direction is at least 670 Hv. The volume ratio of austenite grains in the quench-hardened layer, at the surface of the quench-hardened layer located at the center of the rolling surface in the axial direction, is no more than 30%.
Inventors:
KAWAI TAKASHI (JP)
OHKI CHIKARA (JP)
YAMADA MASAHIRO (JP)
OHKI CHIKARA (JP)
YAMADA MASAHIRO (JP)
Application Number:
PCT/JP2020/034079
Publication Date:
April 01, 2021
Filing Date:
September 09, 2020
Export Citation:
Assignee:
NTN TOYO BEARING CO LTD (JP)
International Classes:
C21D9/40; C21D1/06; F16C19/06; F16C19/26; F16C19/36; F16C33/32; F16C33/34; F16C33/62; F16C33/64
Foreign References:
| JP2008208401A | 2008-09-11 | |||
| JP2007113027A | 2007-05-10 | |||
| JP2019039044A | 2019-03-14 | |||
| JP2019108576A | 2019-07-04 | |||
| JP2001330101A | 2001-11-30 | |||
| US20170328408A1 | 2017-11-16 | |||
| JP2019178727A | 2019-10-17 |
Attorney, Agent or Firm:
FUKAMI PATENT OFFICE, P.C. (JP)
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