Cavitation Research And Structural Modification Of Valve Plate In Axial Piston Pump

Axial piston pump has the advantages of high volumetric efficiency,convenient variable,light weight per unit power and so on.Therefore,it is widely used in high pressure,high power and occasions requiring large flow.However,the movement process of the axial piston pump is more complex,and the valve plate as the high and low pressure conversion area is easy to cause the phenomenon of liquid cavitation,which restricts the development of the piston pump.In this paper,A10 V axial piston pump as the research object,through the combination of theoretical research and simulation analysis method,the valve plate damping groove structure of swashplate axial piston pump is optimized design.The main research contents are as follows:1.The working principle of A10V swash-plate axial piston pump,the research status of valve plate and the common structure of valve plate are introduced.This paper leads to research ideas.2.The formation mechanism and influencing factors of cavitation and cavitation are described.The formation and flow,expansion and contraction,dissolution and collapse of bubbles in oil were analyzed and mathematically modeled by using cavitation dynamics.3.3D modeling of the piston pump flow channel.Secondly,through the gas volume fraction and velocity simulation analysis of the plunger cavity and the process of oil suction and discharge,the change process of cavitation is explained.Then,combined with the velocity cloud images of the oil film clearance of the port pair of the axial piston pump in X and Z axes at different moments,it is shown that with the increase of velocity,the shear force of the oil film of the port pair increases,resulting in the increase of stress leading to cavitation between the oil films.Finally,the outlet pressure of the pump and the internal pressure of the plunger cavity are simulated through the Pumplinx to verify the correctness of the calculation of the fluid model.4.Derivation of the differential equation of the gas holdup in the oil shows that the gas holdup in the connected volume is mainly affected by the internal pressure,material exchange and the total oil mass.Secondly,combined with the differential equation of gas holdup,throttling effect and the energy change of control volume,a centralized parameter model of the piston pump inlet was obtained.Then through the flow analysis of the bubble in the pre-boost of the valve plate,the flow analysis of the bubble in the boost of the damping groove and the flow analysis of the bubble in the pressure relief area,the idea of the design of the damping groove structure is obtained(the pre-boost area needs the damping hole in the triangular groove structure to achieve the maximum auxiliary pre-boost effect in time;The pre-relief area requires damping grooves to reduce the suction time of the plunger chamber to produce fewer bubbles.Finally,the micro analysis on the key area of the valve plate shows that the microbes will cause bubble collapse and impact on the plunger wall surface.5.The simulation study was carried out on the piston pump under different working conditions of oil inlet pressure,spindle speed and swashplate Angle,and the influence of the three factors on the piston pump cavitation was illustrated.Secondly,the damping groove structure of the pressure-boosting region and pressure-unloading region of the valve plate was optimized,and the effects of different structures on suppressing cavitation were compared.A new type of shuttle groove structure is designed and the groove with different widths is simulated and analyzed.Finally,by comparing different damping groove structure design and optimization schemes,a new combined groove structure is designed,which can effectively reduce the impact of cavitation on the piston pump.