Tapered Roller Thrust Bearing and Support Structure
Deflection of the support structure of a tapered roller thrust bearing moves the load inboard along the roller-to-raceway contact. The race and roller have tighter curvatures inboard, so moving the load inboard increases contact stress and decreases bearing life. Modifying the support structure moves the load outboard, reduces contact stress and increases life. The ANSYS finite element software modeled the shaft, bearing bottom plate, bearing top plate and lower support structure. The model also included the roller as a collection of spring elements, connected to a rigid region. This construct modeled load transmission by the roller as well as roller tilting, while avoiding time-consuming surface-to-surface contact calculations. Because all rollers bear the same load in a thrust bearing, a two-dimensional axisymmetric model sufficed to capture the behavior of the bearing. The program output included plots of stress and deflection in the bearing and in the support components. The output also included a listing of spring element forces, which characterized the load per unit length along the roller-to-raceway contact. Iterating over several modifications of the support structure allowed minimization of the maximum contact stress between roller and raceway, and so optimized bearing life.