Journal bearing modification for wind power gearbox based on comprehensive thermo-elastohydrodynamic lubrication and wear coupling

Planetary gear journal bearings (PGJBs) are critical components of wind turbine gearboxes that significantly influence the reliability and cost-effectiveness of wind energy systems. Under harsh, low-speed, high-load, and high-torque conditions, PGJBs remain insufficiently optimized, necessitating precise performance simulations and enhancements. In this study, a comprehensive thermo-elastohydrodynamic mixed-lubrication model was developed by integrating the thermal effects, cavitation, asperity contact, and deformation. The model was validated through comparative analyses with existing approaches, revealing critical lubrication characteristics. Excessively thin oil films at the bearing edges induced severe asperity contact, which poses substantial risk of wear-induced failure. To address this, a running-in model coupled with wear and mixed lubrication analysis was established to investigate the edge modification of PGJBs. The results indicated that the optimized profile derived from the running-in model increases the minimum oil film thickness by 3.97 µm under rated conditions while reducing the contact pressure from 8.98 to approximately 0.001 MPa, with even more pronounced improvements under overload scenarios. The proposed modification geometry enhances the operational performance and reliability of the PGJB, thereby advancing the development of clean energy technologies.