Friction torque in thrust roller bearings lubricated with greases, their base oils and bleed-oils

In this work a series of experimental tests were performed with cylindrical thrust roller bearings (TRB) lubricated with grease. The tested greases were formulated with base oils of different grades and/or nature but also different thickener types.t The friction torque was measured under constant load, while varying the rotational speed, at different operating temperatures. The SKF's rolling bearings friction torque model was optimized to the experimental measurements by calculating the coefficients of friction (COF) under boundary and full film lubrication. It was found that the polymer thickened greases generally show lower friction than typical multi-purpose lithium greases. The base and bleed-oils of each grease were also tested and might show quite different friction torques than the corresponding greases.