Bearing defect data from 8000 railroad roller bearings were analyzed to determine their defect modes and defect rate distributions. Cone bore growth, brinelling, and fatigue were identified as the predominant defect modes as bearings age at least through age 12 years. The observed data were fitted with a Weibull failure distribution and estimates were made of the Weibull parameters. A comparison was also made between the incidence of fatigue spalls and estimates of fatigue life based on the AFBMA method. The results of the study show that, after only two years of service, ten percent of all railroad roller bearings exhibit a defect of one type or another for which at least one component would be condemned if it were in a rework shop. The present AFBMA method of calculating fatigue spalling, modified to account for lubricant film thickness effects, correlates reasonably well with the observed incidence of spalling (10 percent fatigue life of about 11 years). The problem lies in the fact that the AFBMA calculation procedure ignores the other competing defect modes which contribute far more to the overall defect rate than does spalling. One of these, cone bore growth, is a major contributor to the overall defect rate and deserves special attention. The relationship between "defect rate" and "failure rate" is not direct, and an examination of "condemning limit" definitions relative to the progression of bearing failure in service is needed.

  • Supplemental Notes:
    • Paper presented to American Association of Mechanical Engineers Meeting, May 24-26, 1976.
  • Corporate Authors:

    American Society of Mechanical Engineers

    Two Park Avenue
    New York, NY  United States  10016-5990
  • Authors:
    • Krauter, A I
    • McGrew Jr, J M
    • Moyar, G J
  • Publication Date: 1976-5-24

Media Info

  • Features: References;
  • Pagination: 7 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00141115
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Report/Paper Numbers: Paper N. 76-LubS-18 Conf Paper
  • Files: TRIS
  • Created Date: Oct 26 1976 12:00AM