| In some sense, the standard of engineering machinery manufacturing represents the whole standard of the equipment manufacturing industry. Comparing with the imported products in nowadays, the performance of domestic engineering machinery product is unreliable. The main reason of this situation is the backward of hydraulic system in engineering machinery. Since the hydraulic pump is the core component in a hydraulic system, its significance is obvious. In this thesis, take the Rexroth A4VG125HD piston pump, which is widely used in hydraulic system of engineering machinery, as research objects, conduct the following study:1. Give some brief introductions about the basic structure of piston pump, its variable system and variable control modality. Make Summarize about the domestic and overseas research trends on both main part and variable system of the piston pump. Based on a large number of literature, established the research content and methods of this issue.2.Completed mathematical modeling based on exhaustive analyze of the piston pump. During the flow area mathematical modeling, this thesis introduced five valve plate deflection angle as variable parameter:the offset angle, the depth angle and width angle of triangle buffer groove, which made the study on the influence between the continuously changed parameters of the valve plate and the character of pump become possible. During the analysis of variable system, complete the mathematical kinetic model of single piston and swash plate, combine the kinetic model and the structural parameters achieved by measurement, can give intuitive reflection about the function between variable system’s parameters.3.Disassemble the pump, surveying and drawing every component, complete the3D model of this pump in Pro/E. Based on physical structure and mathematical model, modeling the hydraulic model of main part and variable system part in SimulationX. Import the3D model from Pro/E to SimulationX using import module given by SimulationX, add constraints between each component based on the real assemble relationship, complete the kinetic model of pump. Connect two parts of the pump, the hydraulic model send rotation signal of the cylinder,the translation signal of variable cylinder, the stress signal of piston to kinetic model, while kinetic model provide angle signal of swash plate to hydraulic model. Follow the above steps, complete the co-simulation model of whole pump.4.Simulate and get the basic pressure and flux character used the completed co-simulation model, analyze the reason of character spline’s variation. Simulate the function relationship between pressure flux character and the continuously changed parameters of the valve plate, such as offset angle, depth angle and width angle. Utilize the simulate result,the optimal angle range can be informed, pick some specific value close to the range and run simulation, the best value of each parameter can be confirmed. Simulate the steady state and dynamic state character of variable system and study the influence of load pressure, feedback spring’s stiffness and variable cylinder’s diameter. Provide the basis of parameters’value in variable system.5.Make summarize about this issue, pointed out the shortage and give expectation on the further steps. This thesis analyzed the pressure flux character and variable system character from both theoretical side and simulated side. The process of analyze is universal, so it can be used in the research development on piston pump. |
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