# US 7,744,283 B2 · Bearing for alternator and bearing for pulley

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- Number: US 7,744,283 B2
- Document ID: US7744283B2
- Status: Granted
- Kind: B2
- Application number: 10/795,389
- Filed: 2004-03-09
- Published: 2004-09-16
- Granted: 2010-06-29
- Earliest claimed: 2003-03-14
- Assignees: Ntn Corporation
- Inventors: Chikara Ohki; Tomoaki Goto
- Web page: https://patentgrep.com/patent/US7744283B2

## CPC

- F16C 33/62: Selection of substances
- F16C 19/00: Bearings with rolling contact, for exclusively rotary movement (adjustable bearings F16C23/00, F16C25/00 {; electrically insulating bearings H02K5/173})
- F16C 33/30: Parts of ball or roller bearings
- F16C 33/32: Balls
- F16C 33/64: Special methods of manufacture
- F16C 19/06: with a single row or balls
- F16C 2204/66: High carbon steel, i.e. carbon content above 0.8 wt%, e.g. through-hardenable steel
- F16C 2223/16: with carbo-nitriding
- F16C 2240/90: Surface areas
- F16C 2380/26: Dynamo-electric machines or combinations therewith, e.g. electro-motors and generators
- Y10S 148/906: Roller bearing element
- Y10S 384/912: Metallic
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A bearing for alternators and a bearing for pulleys for reducing hydrogen embrittlement or cracking is used when the bearing is in an environment having a severe condition, such as, when hydrogen is generated from grease or the like. The bearing includes a rolling element, an inner ring and an outer ring, and at least one of the rolling element, where the inner and outer rings have a nitrogen enriched layer containing austenite crystal grains having a grain size number exceeding 10.

## Claims

### Claim 1

A bearing for an alternator, supporting a rotor shaft having one end with a pulley attached thereto and having a belt engaged therearound to transmit a driving force to said pulley to allow said rotor shaft to rotate a rotor, the bearing having a rolling element, an inner ring and an outer ring, at least one of said rolling element and said inner and outer rings having a nitrogen enriched layer and containing austenite crystal grains having a grain size number exceeding 10,
wherein said at least one of said rolling element and said inner and outer rings having said nitrogen enriched layer has a surface layer containing globular carbide having an area ratio of no less than 10%, and said at least one of said rolling element and said inner and outer rings is formed of steel of SUJ2 as defined by JIS.

### Claim 2

A bearing posed between a pulley having a belt engaged therearound and a rotative shaft passing through said pulley, the bearing comprising a rolling element, an inner ring and an outer ring, at least one of said rolling element and said inner and outer rings having a nitrogen enriched layer and containing austenite crystal grains having a grain size number exceeding 10,
wherein said at least one of said rolling element and said inner and outer rings having said nitrogen enriched layer has a surface layer containing globular carbide having an area ratio of no less than 10%, and said at least one of said rolling element and said inner and outer rings is formed of steel of SUJ2 as defined by JIS.