POWER LOSS OF GEARBOX BALL-BEARING UNDER AXIAL AND RADIAL LOADS

A new ball bearing behavior model which predicts and locates power los ses in a high-speed gearbox angular contact ball bearing, operating un der axial and radial loads, is presented. Its new features come from t he consideration of both cage action and effect of lubricant film thic kness in the computation of bearing kinematics at equilibrium. Lubrica nt rheological properties are used in order to calculate hydrodynamic and elastohydrodynamic forces in each lubricated contact of the mechan ism. This model considers cage and ball kinematics to be unknowns. The se are obtained by setting motion equations for each bearing element. The computation and the location of power losses are given by the fric tion forces and the sliding speeds among the various bearing elements, i.e., contact between ball and inner or outer ring, ball-cage, and ca ge-ring. The total power loss varies strongly with the rotational shaf t speed and the oil flow through the bearing; nevertheless, it is hard ly sensitive to axial and radial loads. Finally, a significant role of the cage in the power losses is established.