Tribological effects of roughness and running-in on oil-lubricated line contacts

C. C. Chou, J. F. Lin

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


A gear/cam adapter was employed to study various aspects of line-contact lubrication, using oil with extreme-pressure additive at two different concentrations. The effect of run-in on the tribological performance of rollers with two different surface roughnesses was investigated in terms of friction coefficient, wear loss, oil temperature, specimen roughness and electrical resistance. The relation between roller wear loss and the time rate of electrical resistance change was established. Electrical resistance versus oil temperature underwent a dramatic change during testing, a period of rising oil temperature and relatively constant low electrical resistance abruptly becoming a period of relatively constant oil temperature and rising electrical resistance, low wear rates correlating strongly with the second period. The run-in effect on roller wear loss in smooth rollers (Ra = 0.076 (am) is opposite to that in rough rollers (Ra = 0.463 um). The asperity height of the smooth rollers was increased by wear testing irrespective of run-in; however, run-in enhanced the increase in surface roughness. The extreme-pressure additive concentration instead of run-in was the decisive factor in electrical resistance. Frjction coefficients during testing showed a strong positive relation with composite surface roughness.

Original languageEnglish
Pages (from-to)209-222
Number of pages14
JournalProceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology
Issue number3
Publication statusPublished - 1997

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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