Wear Debris Analysis of Grease Lubricated Ball Bearings.

Abstract : An investigation was conducted to experimentally determine the wear surface condition of grease-lubricated ball bearings, by monitoring the wear debris retained in the grease. Testing of six bearings was performed on endurance test machines with grease sample removal. Visual and scanning electron microscope examinations of the bearing surfaces were performed per an established schedule by SKF. Respective grease samples were treated, analyzed, and correlated by NAVAIRENGCEN. A total of four bearings failed during the testing while the remaining two bearings reached time up. The testing, therefore, provided a good distribution of failed and unfailed bearings from which the evaluation of bearing failure or imminent failure detection by wear debris analysis could be established. The results of the wear debris analysis, performed by NAVAIRENGCEN compared to the physical examination of the bearings performed by SKF, showed a good correlation, in terms of monitoring the wear state/condition of the bearings throughout their life. As it appears presently, this analysis technique is best suited to the examination of used grease obtained from dismantled grease lubricated components or in design applications. (Author)