Abstract:Elastohydrodynamic lubrication (EHL) oil film has remarkable elasticity and damping characteristics,which has great impact on the dynamic characteristics of higher pair contact mechanical elements and mechanical systems.Studying the dynamic characteristics of EHL friction pairs and revealing its change rules are of great significance for improving the dynamic design of whole mechanical system.Based on the EHL theory and mechanical vibration theory,the tribo-dynamics coupling model of point contact EHL friction pairs was established.The vibration response of the EHL friction pairs under harmonic excitation was solved by numerical method,the stiffness and damping of the EHL friction pair were identified by the response hysteresis loop of the EHL friction pair.The influence of load,speed and material parameters on the stiffness and damping of the EHL friction pairs was studied by parameter control method.The results show that,within the speed and load range studied,the stiffness and damping of friction pairs increase with the increase of load and ellipticity, and decrease with the increase of velocity and material parameters.The influence of load on stiffness and damping of point-contact EHL friction pair is most significant,the stiffness of friction pair varies significantly with load,velocity and material parameters compared with damping.On the basis of numerical examples,the fitting formulas of the stiffness and damping of the EHL friction pairs with respect to load,speed and material parameters were proposed.The results of numerical comparison show that the fitting formulas proposed have satisfactory accuracy,which can quickly calculate the stiffness and damping of point contact friction pairs under EHL conditions.