This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Effect of Bearing Surface Characteristics on Bearing Oil Film Thickness
Annotation ability available
Sector:
Language:
English
Abstract
The most widely used method of measuring bearing oil film thickness (BOFT) is the “capacitance technique”. It has two implicit assumptions that need to be carefully considered. These are:
- (1) The bearing surfaces are smooth down to the molecular level.
- (2) The dielectric constant is uniform across the interface.
This paper examines each of these assumptions and finds:
- (1) The real MOFT is smaller for a rough surface than the reported MOFT
- (2) The real MOFT is larger if the VI improver concentrates at the bearing surface than the reported MOFT
- (3) The magnitude of the first effect is larger than the second.
For values of MOFT greater than one micron, the reported MOFT values are sufficiently independent of surface roughness and possible adsorption effects that the standard MOFT equation can be used.
Recommended Content
Technical Paper | Interpreting Experimental Bearing Oil Film Thickness Data |
Magazine Issue | SAE VEHICLE ELECTRIFICATION |
Technical Paper | BALL BEARINGS. |
Topic
Citation
Clampitt, B., "Effect of Bearing Surface Characteristics on Bearing Oil Film Thickness," SAE Technical Paper 892153, 1989, https://doi.org/10.4271/892153.Also In
References
- King W. H. U. S. Patent 4,443,754 1984
- Deysarkar A. K. “The Bearing Oil Film Thickness of Single and Multi-Grade Oils - Part 1: Experimental Results in a 3.8L Engine,” SAE 880681 1988
- Naegelin B. Personal Communication 1988
- McMillan M. L. Rosenberg R. C. Murphy C. K. “Viscosity Effects on Engine Wear Under High Temperature, High Speed Conditions,” SAE 780982 1978
- Brandrup J. Immergut E. H. “Polymer Handbook,” John Wiley 1975
- Deysarkar A. K. Spearot J. A. Murphy C. K. “Interpreting Experimental Bearing Oil Film Thickness Data,” SAE 892151 1989