A Mixed Lubrication Theoretical Model and Experimental Verification of Rotary Lip Seals

Abstract

A mixed lubrication model of rotary lip seals using a statistical approach with flow factors based on reverse pumping mechanism has been developed. The model consists of coupled fluid mechanics analysis, asperity contact analysis and deformation analysis. The oil film pressure and shear stress are obtained from solving the Reynolds equation. Using the GREENWOOD- WILLIAMSON surface contact model computes the contact pressure between the lip and shaft. The deformation analysis of lip seals is carried out using the influence coefficient method. Applying the mixed lubrication model to a typical lip seal, the pumping rate and friction torque are the two most important factors of evaluating seal characteristics, which are the output results of theoretical simulation. Most important, the pumping rate and friction torque are measured with bench test designed by the authors. The measurement of these two factors verifies the validity of the mixed lubrication model. For the reverse pumping action of rotary lip seals is resulted from the surface asperities, the influence of roughness on the pumping rate, friction torque and the contact area are carried out by using the verified theoretical mixed lubrication modle.