Influence of oil groove geometry on the lubrication characteristic of planet gear thrust washer

In order to reduce the wear of thrust washer within straight planetary gear set, hydrodynamic lubrication design was studied by way of machining grooves in the radial direction into sides of thrust washer. Such grooves can result in a hydrodynamic pressure to separate the contact surfaces and reduce the wear accordingly. The lubrication characteristics were analyzed for the cases with less number of grooves (2?12) using the finite volume method. Influence factors of the carrying capacity of oil film, oil flow and oil temperature rise were analyzed for both radial and parallel grooves. The computational results of both geometries have the curvilinear trend consistently with little difference in the numerical value. Hence, for design optimization purposes, a radial groove transmission approximation may be justified for a parallel groove design because the numerical solution of radial groove is more convenient to obtain than that of parallel groove.