| Axial piston pump has a compact structure and high power density,which is widely used in the field of Aeronautical fluid transmission.The piston pair is the main friction pair of a plunger pump.Because the friction pair undertakes high speed and heavy load for a long time,while the lubrication condition is quite complex,the friction pair becomes an important factor that affects performance,reliability and life of a plunger pump.Study of the characteristics of a plunger auxiliary oil film is helpful to design and optimization of friction pairs,thus improving the performance of a plunger pump.Based on the study of the motion and force of a swashplate axial piston pump,motion equations of the piston pair are established.According to the external force condition of piston pair,the specific force expression of plunger is derived.According to the true tilt posture of plunger in cylinder bore,the differential equation of plunger auxiliary eccentric piston shaft is derived,and oil film thickness is described by mathematical formula in the Cartesian coordinate system.Taking A10 VSO series plunger pump as the research object and based on the geometric model of piston pump built in Pro/E,the dynamic model of piston pump is established by loading,driving and adding constraints.The displacement,velocity and acceleration curves of plunger are depicted by ADAMS.The hydraulic system model of plunger pump is established using system simulation software AMESim.The hydraulic model and dynamic model are jointly simulated to obtain the pressure simulation curve of plunger chamber,and the construction of the virtual prototype of plunger pump is completed.Based on Reynolds equation,the oil film thickness equation of plunger pair is established,and the oil film thickness field model of plunger pair under plunger tilt condition is solved.The characteristics of plunger auxiliary oil film are simulated by MATLAB software,and change of thickness distribution of plunger side oil film under slanting state of plunger is obtained.Finally,the experimental model pump of plunger auxiliary oil film characteristic is designed,and the experimental system based on the model pump is built.The measurement of oil film thickness under 18 MPa pressure is completed.The correctness of the simulation results of the oil film thickness of the plunger pair is verified by experiments.It is proved that the simulation model of piston pump established in this paper has important guiding significance for the design of axial piston pump. |
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