Study On Oil Film Characteristics Of Piston Pair Of Ultra-High Pressure Axial Piston Pump

The ultra-high pressure of hydraulic system can reduce its weight and volume,which is one of the development directions of hydraulic field.Ultra-high pressure hydraulic pump as the power component of ultra-high pressure hydraulic system,its performance directly affects the reliability of the hydraulic system.Piston pair is one of the key friction pairs in ultra-high pressure axial piston pump.With the increase of load,the leakage at the clearance of the piston pair will increase.In order to reduce the leakage at the clearance of the plunger pair,the clearance value of the plunger pair of the ultra-high pressure plunger pump is smaller than that of the medium and high pressure plunger pump.Therefore,in order to explore whether the plunger stuck in the narrow gap,it is necessary to study the oil film characteristics of the plunger pair under the ultra-high pressure condition,so as to provide a theoretical basis for the optimal design of the plunger pair of the ultra-high pressure plunger pump.This paper takes an ultra-high pressure axial piston pump as the research object,briefly introduces its own structural characteristics and working principle.The motion and mechanical model of plunger components are established,and the posture of plunger components in the plunger chamber under ultra-high pressure is analyzed.The mathematical model of oil film thickness of plunger pairs is established by using cosine theorem in the cross section of plunger,which lays a theoretical foundation for solving the oil film pressure field of plunger pairs below.Reynolds equation of oil film of plunger pair is established by using fluid continuity equation and N-S equation.The finite volume method is used to discretize the Reynolds equation of the oil film of the plunger pair,and the over relaxation iteration method is used to solve the discretization equations.Newton iteration method is used to solve the coupling relationship between the external force,the external moment and the acting force of the oil film on the plunger.The mathematical model of the thickness and pressure of the oil film of the plunger pair during the dynamic change of the plunger chamber is obtained.The mathematical model of thickness field and pressure field of oil film of plunger pair is solved by using MATLAB simulation software.The corresponding change process of oil film thickness field and pressure field of plunger pair with the change of plunger attitude under ultra-high pressure is obtained.The super high pressure plunger pump is reformed by installing a pressure sensor on its cylinder block and regulating the pressure regulating handle of the relief valve.Through the pressure sensor,the oil film pressure characteristics of the plunger pair of the ultra-high pressure axial plunger pump under different load pressures are measured.