Impact Analysis of Helical Gear Mesh Bending Moment on Planetary Gear Journal Bearings Transient Lubrication Performance in Wind Turbine Gearboxes

The journal bearings of planetary gears in wind turbine gearboxes were often designed with the inner holes of the planetary gears and the pin shaft as the shaft sleeve and journal, respectively. However, the meshing bending moment of the helical gears might easily cause misalignment between the planetary gears and the pin shaft, resulting in high risk of edge contact and affecting the operating life. Taking the planetary gear journal bearing of a 6 MW drive chain gearbox as the research object, considering the dynamic effects of radial load, bending moment, and speed of the journal bearing, a transient tribo-dynamic coupling model of the planetary gear journal bearing was established. The dynamic meshing force and time-varying speed of the planetary gear extracted from the SIMPACK dynamic model of the wind turbine drive chains were used as the load and motion boundary inputs for the planetary gear journal bearings. The influences of the helical gear meshing bending moment, input torque, and journal bearing radius clearance on the lubrication performances of the planetary gear journal bearing were analyzed, and experimental verification was conducted. The results indicate that the dynamic meshing force and generated meshing moment of the planetary gear will cause dynamic cyclic changes in the axial positions and deflection angle of the planetary gear, and as the load increases, the oil film/solid contact pressure and misalignment moment of the planetary gear journal bearings will gradually increase. Reducing the radial clearances of planetary gear journal bearings may effectively improve their transient lubrication performance. © 2024 Chinese Mechanical Engineering Society. All rights reserved.