Initiation and evolution of interference wear and pitting for spur gears considering the concurrent effects of meshing impact and mixed lubrication

Extended tooth contact (ETC) leads to specific load paths, introduces periodic overload and lubrication degeneration. These disadvantages cause specific interference wear and pitting. This work proposes a wear-pitting prediction model incorporating ETC, dynamic motion, and mixed EHL to investigate coupling relations between these factors. The model predicts a MI-induced wear-pitting competition phenomenon, indicating that when the film load capacity is improved, an additional pitting streak emerges at 1.2 mm from the pinion tooth tip while the maximum wear depth decreases from 32.9 mu m to 10.2 mu m. Two endurance experiments under different working conditions are performed on the FZG test rig. The predicted wear distribution and pitting areas are consistent with the tested results.