| Axial piston pumps are widely used and are indispensable power components in hydraulic systems.The valve pair is the key friction pair of the axial piston pump.It consists of a rotating cylinder,a fixed valve plate and the gap oil film between the two.The lubrication state of the valve pair will greatly affect the working efficiency and service life of the axial piston pump.The axial piston pump distribution pair maintains a suitable thickness of the gap oil film,which can ensure good lubrication characteristics,effectively improve the working performance of the pump,and extend the service life of the pump.The main research contents and conclusions of this paper are as follows:(1)Taking the axial piston pump valve pair as the research object,the structure of the axial piston pump is introduced,and the working principle of the valve pair and the wedge oil film theory are studied and analyzed.According to the structure and motion law of the piston pump valve pair,the kinematics analysis was carried out,and the equations about the displacement speed of the plunger were obtained,which provided the basis of programming(UDF)for CFD(Computational Fluid Dynamics)simulation.(2)The wedge-shaped oil film of the valve pair appears mixed lubrication in the area near the minimum oil film thickness.The theoretical model of oil film pressure and flow velocity is established using the Reynolds equation,and the wedge-shaped oil film mixed lubrication model of the valve pair is established considering the rough topography of the contact surface.Based on the theoretical analysis of the valve pair,the wedge-shaped oil film dynamic pressure distribution model of the valve pair is established,and the main factors and influence rules that affect the wedge-shaped oil film dynamic pressure distribution of the valve pair are studied.Using MATLAB to solve the Reynolds equation,analyze the dynamic pressure distribution of the wedge-shaped oil film of the valve pair under different working conditions,obtain the dynamic pressure and flow velocity distribution near the minimum oil film thickness of the outer seal belt of the valve pair,and analyze the influencing factors of the minimum oil film thickness.The results show that the wedge-shaped oil film inclination angle and speed of the valve pair are the main factors that affect the dynamic pressure effect of the wedge-shaped oil film of the valve pair of the axial piston pump.(3)Use CFD simulation technology to simulate and analyze the axial piston pump distribution pair.The geometric model of the axial piston pump distribution pair was established using Solidworks software,and the ANSYS/workbench/Geometry modules were selected to extract the flow channel,and the ANSYS/ICEM CFD module was used to mesh the fluid domain to establish the axial The simulation model of the flow domain of the piston pump.The sliding grid and dynamic grid technology are used to simulate the rotation of the cylinder body around the main shaft and the reciprocating oil suction and discharge movement of the plunger,and the simulation model is fully parameterized.The FLUENT module is used to simulate the oil film of the port pair clearance under different working conditions.The distribution of pressure and velocity near the minimum oil film thickness of the wedge-shaped oil film of the valve pair is analyzed. |
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