Numerical and experimental investigations on thermoelastic hydrodynamic performance of planetary gear sliding bearings in wind turbine gearboxes

Abstract

The application of planetary gear sliding bearings (PGSBs) in large wind turbine gearboxes (WTGs) has become an important development trend for high-power wind turbines due to the advantages of improving power density and reducing failure rates. However, the working characteristics of operating at heavy-load conditions and using helical gears to mesh will induce large deformation, axial misalignment, and non-negligible temperature rise in PGSBs. In this paper, a comprehensive analysis model taking into account the influence of axial misalignment, thermal effects, and thermoelastic deformation was presented for the PGSB in WTGs. A full-size test rig for PGSBs was built and simulation experiments were conducted to verify the model. Both the measured oil temperature and film thickness agreed well with the numerical results. The predictions from the model were compared with the results of the isothermal-EHD and rigid-THD models. The comparison results indicated that the pad deformation and temperature rise had obvious effects on the bearing performance and could not be ignored. The effects of bearing clearance and aspect ratios on thermoelastic hydrodynamic performance were analyzed. The numerical results showed that both a lower clearance ratio and a higher aspect ratio could help to reduce the maximum pressure at the bearing edges.