Bearing with improved resistance to micropitting

Patent metadata

Field	Value
Publication number	US-9670959-B2
Application number	US-201314766321-A
Country	US
Kind code	B2
Filing date	Feb 6, 2013
Priority date	Feb 6, 2013
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

A bearing comprising a plurality of rolling elements arranged between an inner and outer raceway thereof. A rolling contact interface is between a first rolling contact surface on at least one rolling element and a second rolling contact surface formed by one of the inner and outer raceways. The first rolling contact surface has a first RMS roughness R q1 and a first roughness pattern γ 1 , expressed in terms of the Peklenik number γ. The second rolling contact surface has a second RMS roughness R q2 and a second roughness pattern γ 2 . To minimize micropitting in the bearing, the rolling contact interface has a surface topography wherein (a) the roughness pattern of the first and second rolling contact surfaces are oriented in the direction of rolling, whereby γ 1 ≧3.0 and γ 2 ≧10.0; and (b) the first and of the second rolling contact surfaces have substantially equal roughness heights, whereby 0.8≦R q1 /R q2 ≦1.25.

First claim

The invention claimed is:

1. A bearing comprising:
a plurality of rolling elements arranged between an inner raceway and an outer raceway of the bearing; and
a rolling contact interface being defined between a first rolling contact surface on at least one rolling element and a second rolling contact surface formed by one of the inner and outer raceways,
wherein the first rolling contact surface has a first RMS roughness R q1 and a first roughness pattern γ 1 , expressed in terms of the Peklenik number; and
wherein the second rolling contact surface has a second RMS roughness R q2 and a second roughness pattern γ 2 , expressed in terms of the Peklenik number,
wherein the rolling contact interface has a surface topography in which:
(a) the first roughness pattern γ 1 of the first rolling contact surface and the second roughness pattern γ 2 of the second rolling contact surface are oriented in the direction of rolling (x), whereby γ 1 ≧3.0 and γ 2 ≧10.0; and
(b) the first rolling contact surface and the second rolling contact surface have a substantially equal RMS roughness, whereby 0.8≦R q1 /R q2 ≦1.25.

2. The bearing of claim 1 , wherein each of the first rolling contact surface and the second rolling contact surface has a roughness skewness, R SK , with a value of R SK ≦−0.1.

3. The bearing of claim 1 , wherein the bearing has a mean diameter d m , and wherein an RMS slope R Δqx of a roughness profile, measured in the direction of rolling, and an RMS slope R Δqy of a roughness profile, measured in a direction transverse to the direction of rolling, of each of the first rolling contact surface and the second rolling contact surface, have the following values when d m ≦300 mm:
R Δqx ≦15 mrad
R Δqy ≦45 mrad,
and have the following values when d m >300 mm:
R Δqx ≦30 mrad
R Δqy ≦90 mrad.

4. The bearing of claim 3 , wherein the first RMS roughness R q1 and the second RMS roughness R q2 have a value (in meters) of ≦8×10 −9 (1000 d m ) 0.55 .

5. The bearing of claim 1 , wherein the bearing is one of: a cylindrical roller bearing, a spherical roller bearing, a tapered roller bearing, a toroidal roller bearing, or a needle roller bearing.

6. A method of manufacturing a bearing ring comprising a bearing raceway, the method comprising:
subjecting the raceway to a grinding operation that creates asperities with a longitudinal directionality on the raceway,
wherein the grinding operation is followed by a mechanical finishing operation in which asperity heights are reduced without modifying the directionality of the asperities to produce a finished raceway having a roughness pattern with a Peklenik number of γ≧10.0.

Assignees

• Skf Ab

Inventors

• Morales Espejel Guillermo
• Stadler Kenred
• Brizmer Victor

Classifications

• Y10T29/49684

  with race making · CPC title

• F16C33/585 Primary

  of raceways, e.g. ribs to guide the rollers · CPC title

• B24B19/06

  for grinding races, e.g. roller races · CPC title

• B23P9/00

  Treating or finishing surfaces mechanically, with or without calibrating, primarily to resist wear or impact, e.g. smoothing or roughening turbine blades or bearings (treatment covered by a single other subclass, see the relevant subclass, e.g. B24C, C21D7/00, C22F1/00); Features of such surfaces not otherwise provided for, their treatment being unspecified · CPC title

• F16C19/22

  with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings · CPC title