To investigate the influences of liquid resistance on the main valve performance, a hydraulic experimental system for pure water was built, and three sizes of throttle nozzles with diameter 1.2mm, 1mm and 0. 8mm were separately serial connected to pilot valve to be tested, then the corresponding pressure-flow characteristics were tested. Using AMESim software, a simulation model was built based on the structure of pilot operated valve. Combining with the experimental data of pressure-flow characteristics, the simulation results of opening pressure, running pressure and poppet displacements were studied. The results indicate that the hydraulic resistance of throttle orifice affects mainly the openning pressure and has only a little influence on the flow characteristics of main valve. The pressure difference between high pressure chamber and low pressure chamber are too small to open the main valve when using 1.2mm throttle oriffice, the openning pressure using lmm throttle orifice is 0.24MPa, 0.8mm is 0.2MPa. Considering that the small hole is easy to choke, then 1mm throttle orifice is the optimization scheme.%为研究液阻对主阀性能的影响,搭建了纯水液压试验平台,分别对孔径为1.2mm、1mm和0.8mm三种规格的节流喷嘴与所选先导阀串联情况下的压差一流量特性进行了试验.利用AMESim软件建立了先导式电磁阀的仿真模型,结合节流喷嘴和先导阀压差一流量试验数据对开启压力、工作压差及阀芯位移等进行了仿真.仿真结果表明:节流孔液阻主要影响主阀开启压力,对主阀流动特性影响较小.选用孔径为1.2mm的节流喷嘴时,主阀由于高低腔间压差太小,无法开启;选用孔径为1mm和0.8mm的节流喷嘴时,主阀开启压力分别为0.24MPa和0.2MPa,考虑大的孔径抗阻塞能力强,故孔径为1mm的节流喷嘴为优选方案.
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