Research On Sealing Performance Of Reciprocating Skeleton Oil Seal With Fluid-structure Interactions

Reciprocating skeleton oil seal used for automobile shock absorber seals since it can prevent the fluid from escaping into the environment through the narrow clearances between piston rod and a rod guide.Once the reciprocating skeleton oil seal fails,it will cause a large amount of leakage of the automobile shock absorber,which will affect the damping behavior of automobile shock absorber and will eventually affect the stability and ride performance in automotive.So the leakage has become a key factors to evaluate the sealing performance of the reciprocating skeleton oil seal.Therefore,the research method of numerical simulation combined with experimental measurements is used to study the sealing performance of reciprocating skeleton oil seal,and lays a theoretical foundation for improving the seal design of reciprocating skeleton oil seal.The main research contents are as follows:The steady fluid lubrication model in the sealing interface was established based on EHL theory.The model couples the mechanics of solid,fluid and deformation analyses together.By solving the model with numerical iteration method,the influences of the rod speed,the amplitude of the rough peak and the initial film thickness on the sealing performance of reciprocating skeleton oil seal under different distribution form of the rough shape conditions was obtained.The transient fluid lubrication model in the sealing interface was established by considering the effect of oil film extrusion.The variation of film pressure,film thickness and leakage with frequency and amplitude under transient conditions was obtained by analyzing the model.The steady mixed lubrication model in the sealing interface was developed by considering the influence of cavitation and roughness.The model is coupled with solid mechanism,fluid mechanism,asperity contact mechanism,and deformation mechanism analysis together.The effects of the rod speed,the seal surface roughness and the fluid viscosity on the sealing performance of reciprocating skeleton oil seal was studied.The leakage experiment research was carried out on the speed ratio test rig to verify the correctness of the numerical simulation results of mixed lubrication model.The influence of the speed ratio,the rebound force of piston rod,the temperature of shock absorber and oil seal structure on the leakage was analyzed.Comparison of the numerical simulation results and the corresponding experimental results,it was found that there are in good agreement,which verifies the effectiveness of the mixed lubrication model proposed.In order to study the friction characteristics of reciprocating skeleton oil seal,the friction force experiment was investigated by using the reciprocating friction test rig.The curve of the friction force changing with displacement was obtained through experiment,and the law of friction force changing with rod speed,lubricant oil temperature and lubricant oil pressure was analyzed.The results show that the direction of friction force is opposite between instroke and outstroke.The friction force will change abruptly during the start-stop and reversing of the piston rod.The friction force is greater in the first cycle both instroke and outstroke.