Thin layer flow and film decay modeling for grease lubricated rolling bearings

A model is presented to predict lubricant supply layer changes on tracks in rolling bearings due to centrifugal forces and elastohydrodynamic contact pressure. Experimental validation is shown for centrifugal force driven free surface flow, and layer thickness (film thickness) decay in single elastohydrodynamically lubricated contacts. The model allows prediction of lubricant migratory trends in bearings. The pressure ejection driven layer/film thickness decay can be predicted without the need to solve rolling element-raceway starved elastohydrodynamic contact problems for millions of overrollings. The model provides worst case estimates of a required (local) resupply interval, and contributes to improved lubricant related bearing life predictions.

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► Development of thin layer flow model for lubricant layers on tracks in bearings.
► Experimental validation for flow on rotating raceways.
► Prediction of film thickness decay in EHL contacts with experimental validation.
► Extension to film decay in bearings using simple approximate formula.
► Perspectives for advanced bearing analysis and lubrication life prediction.