Analysis Of Lubrication Characteristics Of The Port Pair Of Axial Piston Pump With Four Ports Window

Nowadays,with the development and integration of the global economy,construction machinery has ushered in new reforms and developments,and the demand for construction machinery around the world is also increasing."Made in China 2025" is at a critical day for rapid development.Product environmental protection and product quality are more demanding.As one of the essential power components in contemporary hydraulic systems,it is widespreadly used in industry,agriculture,aerospace,petrochemical,engineering and other fields.Under the call of the country’s construction machinery policy,follow the production of green energy saving,and adapt to the society’s demand for high-power,large-displacement plunger pump.a new type of axial piston pump—a four-assignment window axial piston pump is proposed.The structure of the axial piston hydraulic pump with four assignment windows is more complicated,and it also puts forward higher requirements on the lubrication performance of each friction pair distribution pair,especially the distribution pair,as a key friction pair,its friction and wear conditions directly affect the pump performance Performance and service life.The research content of this paper mainly analyzes the distribution characteristics of the four-port axial piston pump,and takes the distribution pair oil film as the research object to study its lubrication characteristics.The main work is as follows:Firstly,construct a three-dimensional model of the axial piston pump with four distribution windows,and analyze the distribution principle according to the structure of its distribution pair.Based on the movement law of the piston pump,the kinematics analysis of the main components of the piston pump is carried out.The mathematical model of the plunger pump is established,and the change law and influence of the fluid density and viscosity under the high-speed and high-pressure working conditions of the plunger pump are considered.The analytical model of the axial plunger pump with four distribution windows is established,and the flow pattern of the fluid in the key parts of the plunger pump is analyzed to select the turbulence model suitable for the plunger pump: RNG model.The fluid simulation software Fluent is used to carry out CFD simulation.Firstly,by extracting the flow cavity of the plunger pump,a geometric model of the fluid domain of the plunger pump is established.Perform high-quality meshing on its computational domain model.Use dynamic grid technology and sliding grid technology to realize the movement of the plunger pair and flow distribution pair of the plunger pump,and write UDF(user subroutine)to write the motion equation of each plunger.Finally,select the solver and fluid medium,set the boundary parameters,and initialize before the simulation,etc.,a complete CFD simulation model of the plunger pump is established.Finally,by assigning different outlet pressure values and slippage speeds to change the load pressure and spindle speed of the plunger pump,at the same time by setting different dynamic viscosity values of the oil,simulate the four-port axial piston pump port pair oil film under different working conditions.Pressure field and velocity field.By comparing the visualization results,the dynamic flow field characteristics of the four-port pump distribution pair are analyzed.Finally,the leakage equation of the four-port plunger pump valve pair is deduced,and the relationship between the leakage and the load pressure,the oil film thickness and the wrap angle of the valve groove is obtained.