Study On Film Lubrication Characteristics Of Spherical Valve Pair In Axial Piston Pump

Valve plate pair is one of the key friction pairs in axial piston pumps.They can be divided into plane and spherical according to their different structures.The spherical valvedistributing conical cylinder block has better resetting performance than the flat valvedistributing cylinder block,so it is widely used in high pressure and heavy load applications.However,under alternating load,the real-time change of the oil film state of the distribution auxiliary and the uneven distribution of the oil film thickness are easy to cause problems such as friction,wear and leakage.Therefore,it is of great significance to analyze the influence of lubrication state of oil film of spherical port pair under different operating conditions to improve the performance of piston pump.In this paper,the lubrication state of the oil film of the spherical distribution pair is taken as the research object,and the mathematical model of the lubrication characteristics of the clearance oil film of the spherical distribution pair is established,and the dynamic formation rule of the spherical oil film with the rotation of the cylinder block is obtained.The lubrication characteristics of oil film under different operating conditions and inner and outer sealing belt parameters are analyzed by numerical solution method.The accuracy of the lubrication state of the oil film of the port pair under different operating conditions and the limit operating condition in case of failure is verified by test.The main contents of this paper are as follows:(1)Analyse the mechanical characteristics of conical cylinder block,define the balance relationship between spherical oil film counter-thrust and cylinder block compression force,establish the mathematical model of spherical oil film pressure field and thickness field,and analyze the change pattern of oil film pressure field and thickness field in one cycle by numerical solution method.(2)The periodic variation characteristics of oil film pressure and thickness field on spherical surface under different pressure and speed conditions are studied,and the oil film lubrication characteristics under different inner and outer sealing band widths are analyzed.The influence laws of different operating conditions and inner and outer sealing band widths on cylinder body overturning attitude are obtained.(3)Design and build the spherical oil film characteristic test bench,test the change rule of oil film thickness with time at different port plate locations,get the change rule of oil film thickness under different outlet pressures,observe the surface shape of spherical oil film under limit pressure,and verify the accuracy of theoretical model.