Research On Series-parallel Open-circuit Axial Piston Pump

With the progress of the times,hydraulic technology has become particularly important.With the rapid development of hydraulic technology,the high pressure of hydraulic transmission is increasingly required,so higher requirements are put forward for the flow and pressure of hydraulic pump.In modern hydraulic transmission,axial piston pump is widely used in various mechanical equipment because of its advantages of small size,high transmission power(high speed and high pressure),high efficiency,convenient variable control and long service life.In order to develop towards high pressure and large flow,this paper puts forward the research of series-parallel open-circuit axial piston pump based on open-circuit axial piston pump,so as to realize series supercharging and parallel large flow output.In this paper,the principles of four open-circuit axial piston pumps are introduced firstly.The special structure and principle of open-circuit axial piston pumps,especially the multi-channel full-flow self-cooling open-circuit axial piston pumps,are the latest research results.The flow rate can achieve 100% cooling,and the test results are better.The principle and feasibility of series-parallel connection of the above four open-circuit axial piston pumps are analyzed.At the same time,an automatic series-parallel open-circuit plunger pump is designed,which can be switched between series and parallel by adding an electromagnetic reversing valve.With the increase of the number of stages of the plunger pump,the output of ultra-high pressure and large flow can be realized.Then,the flow and flow pulsation analysis of two-stage and three-stage series-parallel open-circuit axial piston pumps are carried out,and the flow and flow pulsation analysis of multi-stage series-parallel open-circuit piston pumps is deduced,and the influence of indexing angle on flow and pressure pulsation is found,and then an optimal indexing angle is found to reduce their pulsation and improve pump efficiency and performance.The simulation model of open-circuit axial piston pump is built by Amesim software,and then the simulation models of two-stage series and two-stage parallel open-circuit axial piston pumps are built.Through the series pressure pulsation curves and parallel flow pulsation curves drawn,it is proved that the open-circuit axial piston pump can realize the function of series pressurization and parallel flow superposition,and the influence of indexing angle on pressure and flow pulsation is verified,and then it is deduced that the same rule exists for multi-stage series-parallel open-circuit piston pumps.According to the series connection of open-circuit plunger pumps under high pressure,the strength of pump shell and screw is checked.Through the simulation of traditional cast iron under different pressures and the analysis of displacement deformation,it is found that cast iron has a large deformation under high pressure and is not suitable for working under high pressure.Therefore,a new material,Q345 steel,is selected.Through the analysis of displacement deformation of Q345 steel,it can be obtained that this material can work under high pressure,and with the gradual increase of series pressure,the pump shell can be thickened.Through theoretical strength check and simulation check,it is proved that the selected M20 screw 45 steel material is analyzed under three-level pressure,which meets the strength requirements.If ultra-high pressure is achieved,the bolt will be selected with higher precision.Finally,by setting up an experimental platform,it is verified that the open-circuit plunger pump can realize series boosting and parallel large flow output,and the reversing valve can realize series and parallel switching.