Optimized Design and Lubrication Friction Performance of Elliptical Micro-textures in Gear Surfaces
Gear transmissions under high-speed and heavy-load conditions frequently fail due to incomplete lubricating films, leading to scuffing and severe wear. This study introduces elliptical micro-textures on gear tooth surfaces to enhance hydrodynamic lubrication. A CFD model, based on the Navier-Stokes equations with an incompressible Newtonian fluid assumption, simulated the effects of area ratio (δ), ellipticity (γ=rb/ra), inclination angle (θ), major axis radius (ra), and depth (h) on dimensionless load capacity (W*), wall friction force (F*), and dynamic pressure coefficient (K=W*/F*). Orthogonal rolling-sliding wear tests on cylindrical rollers validated the simulations. Results indicate that area ratio and inclination angle are the most influential parameters, with optimal ranges of 25%-30% and 45°, respectively. The optimal texture parameters were identified as h=20 μm, ra=150 μm, γ=0.7, and θ=0°. Gear tests with these optimized textures showed a transition from severe adhesive wear to minor scratching, with maximum and minimum damage area ratios reduced by 81.11% and 76.97%, respectively, compared to untextured gears. The study acknowledges limitations due to isothermal, incompressible assumptions and neglect of thermal effects, surface elastic deformation, and cavitation. Future work aims to develop a thermo-elastohydrodynamic lubrication model incorporating operating parameters for precise prediction under extreme conditions.