Analysis Of Lubrication Characteristics Of Piston Pair In Axial Piston Pump Based On Fluid-Structure Coupling

The friction pair in the axial piston pump is prone to friction and wear during operation,resulting in the decline of pump performance.The piston pair of axial piston pump involves multiple physical fields,and the lubrication mechanism is complex.It is of great significance to study the lubrication characteristics of the piston pair to improve the lubrication state of the piston pair,the design and manufacture of the piston pair,and even the design and manufacture of the axial piston pump.The piston pair and hydraulic oil are key components of an axial piston pump,which have a significant impact on the performance of the piston pump.This thesis conducts relevant research on the lubrication characteristics of the piston pair of an axial piston pump,and the main research content is as follows:(1)A fluid-structure coupling simulation model for the lubrication of the piston pair of an axial piston pump has been established.First,the oil film pressure and thickness equations of the piston pair are established,the force analysis of the piston is carried out,the force balance equation is established,and the solution method of the oil film pressure equation and the force balance equation is given.Based on AMEsim,the simplified model of the axial piston pump is established,the movement characteristics of the piston are analyzed,the dynamic pressure curve of the piston chamber is calculated,and the dynamic pressure of the piston chamber is taken as the boundary condition for the calculation of the oil film pressure of the piston pair.A three-dimensional model of the piston pair for finite element analysis is established.The fluidstructure coupling calculation of the oil film of the piston pair is realized by using Matlab and Abaqus.The fluid domain calculation is realized by Matlab,and the solid domain calculation is realized by Abaqus.The real-time data transmission between the two is realized by using Python programming.(2)The impact of elastic deformation of the piston pair and oil physical properties parameters on lubrication characteristics was analyzed,and the conclusions obtained mainly include:The surface elastic deformation of the piston pair has a significant impact on the oil film lubrication characteristics of the piston pair.After considering the elastic deformation,the maximum pressure of the oil film significantly decreases,the area with extremely thin oil film thickness decreases,and the axial viscous friction force decreases,but the leakage of the piston pair increases.An increase in oil stiffness will increase the maximum pressure of the oil film,but it has no significant effect on axial viscous friction force and leakage.The change in oil viscosity will significantly affect the lubrication characteristics of the piston pair.As the oil viscosity increases,the axial viscous friction force increases,but the leakage of the piston pair will significantly decrease.(3)The impact of piston structural and working parameters on lubrication characteristics was analyzed,and the conclusions obtained mainly include:Increasing the inclination angle of the piston will increase the axial viscous friction force,while the leakage of the piston pair shows an opposite trend in the oil suction and discharge areas.Increasing the inclination angle of the swashplate will increase the axial viscous friction force,increase the power loss of the piston pump,reduce the leakage in the oil discharge area of the piston pair,and increase the leakage in the oil suction area.The impact of structural changes in the piston on the lubrication characteristics of the piston pair is mainly reflected in elastic deformation.The elastic deformation of the hollow piston is smaller,the maximum oil film pressure is higher,and the axial viscous friction force is greater,but the leakage of the piston pair is relatively lower.The elastic deformation of the solid piston is greater,the maximum pressure of the oil film is lower,the axial viscous friction force is reduced,and the leakage is increased.As the load pressure increases,the oil film pressure increases,the elastic deformation of the piston pair increases,and the axial viscous friction force and piston pair leakage also increase.