The Matchability Design Of The Electrohydraulic Cartridge Servovalve With Large-Flow Rate And The Pilot Stage

The pilot stage of large flow electro-hydraulic servo cartridge valves (LFEHSCV for short) are key element in the whole cartridge valves,which ususlly are acted by high-performance servo valves.Direct drive style proportional servo valves(DDSPV) works as one of the pilot stage, synthesizes the advantages of proportional and servo valves and have the comprehensive merits on dynamic response, accuracy,price and reliability,so they are applied widely among various industries. As the pilot stage of cartridge valves.flow rate and dynamic response of DDSPV directly affects the main stage dynamic performance,which is key factor in improving the performance of LFEHSCV. Under the background, the paper revolvs around the aim about how to advance the performance of LFEHSCV, expatiating the optimize design of DDSPV.The main content are as follows:In chapter 1.The research background of the issue are introduced firstly,and the paper generally discusses technical state about LFEHSCV.Next the research situation of the pilot stage at home and abroad are paid attention significantly.Finally the paper proposes the research content and solutions.In chapter 2.Optimize the pilot control stage for the LFEHSCV.The aim of optimize is improve the dynamic response of LFEHSCV,and the pilot stage flow rate and pressure depend on the demand of the LFEHSCV dynamic response.When the dynamic response is determined,the flow rate of the pilot stage is corresponding to control chamber of spool.According to relevant standard and specification, relevant parameters of the pilot control chamber is determined.Then the load forces loaded on the spool are thoroughly analysed through parameters estimation, theoretical calculation, finite element simulation,finally dynamic response of cartridge valves will be analysed by simulation.In chapter 3. On the basis of the flow rate required by the pilot control channel for oiling,the spool of DDSPV would be redesigned.The stroke of spool is lengthened to increase the flux,and the flow force loaded on the moving spool is researched in detail by CFD(computational fluid dynamics) simulation.After confirming the flux and stroke of the DDSPV, the proportion electro-magnet is selected based on force-needed.To check relative paremeters about proportion electro-magnet,the software Ansoft is used to simulate the displacement-force curve.especially focusing on the influence of air gap, radial clearance,the angle of the magnetic ring. And multigroup reiterative simulation and data are analysed to determine the force F(X, IN) and inductance L(XX, IN).Then based on the co-simulation of Ansoft and AMesim,the dynamic performance of DDSPV and LFEHSCV are elaborated.The results show dynamic response of LFEHSCV is increased obviously.In chapter 4.Experiments about DDSPV are conducted,and results show displacement-force curve is in accordance with the simulation results.At the same time,experiments research on LFEHSCV control system are conducted.The results show dynamic performance of LFEHSCV which is redesigned is increased substantially under open-loop step test and its control performance on shot cylinder is high.In chapter 5.Some conclusions of the paper are shown,and the further research content are proposed.