| Axial piston pump is one of the most important power components of hydraulic equipment,modern industry has put forward higher requirements for its life and reliability.As the key friction pair of the axial piston pump,the valve-plate pair directly affects the life and reliability of the axial piston pump.Compared with the plane valveplate pair with cylindrical cylinder block,the spherical valve-plate pair with conical cylinder block has a compact structure and strong reset ability,which is more suitable for high-speed and heavy-duty conditions.Therefore,the spherical valve pair with conical cylinder block has been widely used.Due to the lack of research on the oil film lubrication characteristics of the spherical valve-plate pair with conical cylinder block,this study carried out lubrication characteristics analysis and structural optimization research on the spherical valve-plate pair with conical cylinder block.In this research,the dynamic behavior of the conical cylinder block is theoretically analyzed,the lubrication model of the spherical valve-plate pair oil film is established,the influence of working conditions on the oil film pressure field,thickness field,leakage and friction is discussed,this paper also analyzes the changes of lubrication characteristics of the spherical valve-plate pair under different wear profile,and a multi arc groove spherical valve-plate structure is proposed.This research provides a theoretical basis and reference for the analysis and optimization of the lubrication performance of the spherical valve-plate pair with conical cylinder block.Mainly as follows:First,this research perform kinematics and dynamics analysis on the conical cylinder block and piston-slipper assembly,and establishes lubrication model of the spherical valve-plate pair oil film considering the centrifugal force of the oil,and analyze the spherical valve-plate pair oil film leakage flow and force calculation model,realize the analysis of the lubrication characteristics of the spherical valve-plate pair with conical cylinder block.Secondly,the influence of working pressure and working speed on the mechanical characteristics,oil film bearing characteristics,and lubrication characteristics of the spherical valve-plate pair is analyzed separately.The results show that the cylinder block compression force and torque increase with the increase of pressure,while the speed has little effect on compressing force;the increase of the pressure and speed will lead to the aggravation of leakage and friction.Then,the axial piston pump was subjected to high-pressure steady-state tests with different lengths of time,and the surface profile scanning test was used to obtain the morphology of the spherical valve-plate pair with different degrees of wear;and the simulation of the spherical valve-plate pair under the wear profile was carried out to analyze the influence of abrasion on the bearing characteristics and lubrication characteristics of the spherical valve-plate pair.The results shows that the abrasion first appears in the form of arc-shaped scratches,concentrated on the outer edges of the inner and outer sealing belt,at the same time,the arc-shaped scratches contribute to the formation of dynamic pressure,which improve the tilt of the conical cylinder block and the loss of friction and leakage.Finally,a multi-arc groove spherical valve-plate structure is proposed,and the bearing characteristics and lubrication characteristics under the three arc groove structure parameters are compared and analyzed,the results shows that the structure can effectively improve the oil film lubrication performance;genetic algorithm is used to optimize the arc groove structure parameters for multi-objective optimization,and obtain the optimized Pareto solution set;by setting the selection criteria,use the linear weighting method to filter the final solution set,and the final solution set individual can effectively improve the lubrication performance of the spherical valve-plate pair. |
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