Cioc, Carmen; Moraru, Laurentiu; Kahraman, Ahmet; Keith, Theo G
This paper outlines an integrated approach to analyzing elastohydrodynamic lubrication (EHL) of helicopter transmission gear surfaces with asperities. The approach involves a generalized formulation that solves the unsteady Reynolds equation in conjunction with a seizure model based on both temperature and plasticity limits. A two-slope viscosity-pressure model is used to avoid overestimation of the lubricant's viscosity under heavy loads. Both lubricated and starved conditions are considered. the 3-D description of rough tooth profile surfaces is measured using a non-contact surface profiler. The pressure distribution, film thickness distribution and the temperature rise at the contact surface are predicted as a function of the gear operating conditions including normal load, lubricant temperature and rolling / sliding speed.