Study On Mechanism Of Fretting Reciprocating Seal And Friction And Wear Behavior Of Inline Pump

The in-line pump,which is the power component of the hydraulic transmission system,is widely used in the construction machinery,automobile,modern ship and even aerospace products.As one of the key components in the hydraulic transmission system,the in-line pump is an energy conversion device which can convert mechanical energy into liquid pressure energy through its internal structure.The sealing surface structure of the in-line pump belongs to the micro-reciprocating sealing structure,which is the key to ensure the reliable operation of the in-line pump.The sealing is completed by the combined sealing ring which produces elastic deformation or plastic deformation when the sealing surface is compressed.In the working process of the in-line pump,because the relative displacement between the contact surface where the combination sealing ring is located is very small,it is in the fretting seal state,most of the wear debris will be trapped in the contact area between the interface and then it will produce very small oscillatory motion.This phenomenon will lead to the crack nucleation and growth in the repeated movement,resulting in fretting wear phenomenon,which will result in the final failure of the seal ring.The failure of the sealing ring will lead to the leakage of the sealing system,which will even pose a serious threat to the safety of life and property.In order to solve the above problems,according to the actual working conditions of the in-line pump,this thesis starts with the selection of sealing materials,and takes the polymer sealing material of the combined sealing ring（UHMWPE,PEEK,PTFE+7%carbon fiber,PTFE+7%carbon fiber+5%Mo S₂,PTFE+40%）as the research object.Firstly,the micro-friction and wear test design of the five sealing materials is carried out according to the actual working conditions of the in-line pump,and the micro-friction and wear test results of the five materials are analyzed and compared in combination with the friction coefficient,wear amount,contact width,and so on.Finally,the material will be selected.Then,the numerical simulation model is used to model the sealing ring model,and the material data of the optimal material after the material selection in the micro-friction and wear test is substituted into the simulation model of the sealing ring,and the solution is carried out.At the same time,the sealing leakage performance is analyzed according to the fluid-structure coupling model of the micro-reciprocating seal.Finally,according to the wear law of the material dynamic friction and wear test,combined with the wear contour prediction theory,the wear depth at the contact surface of the composite seal ring is modeled.According to the wear simulation results of the nodes in each period of time,the wear law is analyzed and the life is evaluated.The research of this thesis will provide material selection basis for composite seals in hydraulic systems such as in-line pumps under micro-reciprocating seals,provide technical support for the selection and application of engineering plastics under different friction conditions with micro-reciprocating seals,and also provide reference for the wear and life evaluation of related materials.