Effect of meshing-induced deformation on lubrication for journal planet gear bearings

To increase the power density and reliability of wind turbine gearboxes (WTGs), journal planet gear bearings (JPGBs) are increasingly employed in their low-speed planet stages. Except for the pressure- and temperature-induced deformations, the JPGB is also structurally deformed by the gear pair meshing in this application, complicating the lubrication and deformation characteristics. Considering the above meshing-induced deformation, a thermo-elasto-hydrodynamic (TEHD) model is proposed for the JPGB, whose deformation is predicted using a self-programmed procedure based on the finite element method (FEM). Besides, this model is verified through a lubrication experiment of the JPGB in the WTG. It is found that the appropriate meshing-induced deformation, varying periodically in the meshing process, can improve the TEHD and misalignment behaviors of the JPGB due to the load-carrying region expansion or twice hydrodynamic action. This phenomenon becomes increasingly obvious with increasing the WTG's input power and the planet's inner radius.