Effect of non-Gaussian roughness tooth surface on lubrication state of grease lubricated spiral bevel gear under mixed-thermal elastohydrodynamic effect

Currently, a low-altitude economic strategy is proposed. The lubrication state of gear systems critically influences the reliability of oil-powered heavy-duty unmanned aerial vehicles. Simultaneous numerical estimation of grease-lubricated gear lubrication states and non-Gaussian tooth surface roughness distributions remains underexplored. In this study, we developed a distribution model for gear surface roughness during machining, which couples the mixed-thermal elastohydrodynamic model for grease-lubricated spiral bevel gears developed by our research group. The research results demonstrate that the ratio of the average oil film thickness to the peak roughness is the dominant factor governing the influence of roughness distribution on film thickness. An increase in torque at low speeds significantly mitigates the effects of varying roughness distributions. Additionally, surface roughness with high kurtosis and positive skewness effectively reduces tooth surface temperature rise.