Influence of concave-convex composite texture on the tribology and transmission performance of wet clutch couples

Based on the differential requirements for friction performance of wet clutch coupling pair under hydrodynamic, mixed and boundary lubrication states, a design of concave-convex composite texture on steel sheet surface is proposed and a theoretical lubrication model is established. Simulation results indicate that suitable composite texture can regulate and control tribological performance during the engagement process. Experimental results demonstrate that the concave-convex composite texture design can reduce friction coefficient by about 5.0%5.5% during the early engagement with high-speed sliding, while increase it by approximately 37.4%- 47.7% at the later engagement phase with low-speed sliding. This validates the comprehensive effect of composite texture in reducing film shear friction during hydrodynamic lubrication stage and increasing friction due to anchoring during boundary lubrication stage.