Effects of roller profile on grease lubrication and fatigue properties of RV reducer crankshaft

Due to the prolonged operation of Rotate Vector (RV) reducers under harsh low-speed and heavy-load conditions, the crankshaft as its core transmission component is prone to fatigue failure. To improve the fatigue life of the crankshaft, this study proposes a lubrication-fatigue life analysis method for the RV reducer crankshaft rolling bearings through kinematic analysis, Thermal-Elastohydrodynamic Lubrication (TEHL) model, subsurface elastic stress calculation and fatigue life calculations. The model’s accuracy is confirmed by experimental validation. The influence of different roller profiles on lubrication performance and life is analyzed, and the preferred roller profile scheme is proposed to enhance the fatigue life. The key research findings indicate that the preferred roller profile can effectively reduce the stress concentration at the roller end and the subsurface von Mises stress peak by approximately 15%, while significantly suppressing subsurface fatigue crack initiation and extending the fatigue life of the crankshaft by about 30%.