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Correlation of asperity contact-time fraction with elastohydrodynamic film thickness in a 20-millimeter-bore ball bearingElastohydrodynamic film thicknesses and asperity contact-time fractions were measured for a 20 mm bore ball bearing by using the capacitance and conductance techniques. The bearing was thrust loaded to 90, 445, and 778 N. The corresponding maximum stresses on the inner race were 1.28, 2.09, and 2.45 GPa. The test speed ranged from 400 to 15,000 rpm. The test bearing was mist lubricated with a MIL-L-23699A turbine oil. The temperature was 27 C. The experimental results were correlated to give the percent film (no-contact-time fraction) as a function of measured film thickness. Measurements were made for three test series that represented the test bearing in various conditions of run-in. The measurements show that the percent film changes with bearing run-in time. The experimental results agreed well with theoretical predictions based on surface trace analysis for a new bearing. For the run-in state, they agreed with previously reported experimental results. The results show that asperity contact existed at a film thickness-roughness ratio lambda of 6.0 or less for a new bearing. After run-in, no asperity contact occurred at a lambda of 3.5 or greater.
Document ID
19790025305
Acquisition Source
Legacy CDMS
Document Type
Technical Publication (TP)
Authors
Coy, J. J. (NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 3, 2013
Publication Date
October 1, 1979
Subject Category
Mechanical Engineering
Report/Patent Number
AVRADCOM-TR-79-26
NASA-TP-1547
Report Number: AVRADCOM-TR-79-26
Report Number: NASA-TP-1547
Accession Number
79N33476
Funding Number(s)
PROJECT: RTOP 505-04
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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