Effect of surface roughness on the gear performance based on the mixed-THEL model

Purpose This paper aims to investigate the gear performance during meshing. The effects of line load, velocity and rough surfaces (kurtosis and skewness) on the lubrication characteristics and fatigue life of gears were analyzed. Design/methodology/approach In the mixed thermoelastohydrodynamic lubrication (TEHL) model, the distributions of pressure and film thickness are predicted using the Reynolds equation. The elastic–plastic rough contact model is used to calculate the contact force and area. To predict the fatigue life of the gears, the Dang–Van fatigue model is used to obtain the fatigue parameters under different line loads, velocities and rough surfaces. Findings The skewness of rough surfaces has a more significant effect on gear performance. In addition, according to fatigue parameters, it is found that when the load is too large, it leads to an increase in the probability of gear failure. Originality/value In this paper, a mixed TEHL model considering the effects of kurtosis and skewness is developed for the line contact to predict the mixed lubrication problem during gear meshing. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2024-0356/