A Performance Study Of The Proportional Valve Based On The PWM High-Speed On-off Valve Pilot Hydraulic Bridge Road

The high-speed on-off valve usually uses for small power condition or as the pilot, which determined by its small throughflow. The paper mainly research on the performance of the proportional valve used PWM high-speed on-off valve hydraulic bridge road as the pilot. The high-speed on-off valve pilot hydraulic bridge road has the advantages of simple control and strong ability to resist pollution. However, the problems of dead zone characteristic and small throughflow, which exists in itself, and the low precision, slow response speed, spool vibration which caused by above problem, these factors become a difficulty affecting the development of the high-speed on-off valve.Using the proportional valve based on high-speed on-off valve pilot hydraulic bridge road as the research object, this paper analyzes the dead zone characteristic and no-load flow characteristic, also analyzes the low control precision and slow response speed of the main valve, which caused by the dead zone and small throughflow of four high speed on-off valve pilot hydraulic bridge road. From two aspects of theory analysis and simulation analysis, the paper analyzes the factors that affect the main valve control precision and response speed. The method improving control precision is put forward, which through differential method is used by the pilot hydraulic bridge road, the rectangular valve port is adopted by main valve, and electric feedback is adopted by spool displacement. And also the method improving response speed is put forward, which the pilot bridge road adopts the double valve parallel mode to oil supply. Finally, after considering several methods improving control precision and response speed, the structure is put forward, which changing the pilot bridge road made up four high-speed on-off valve to six, the main valve adopts rectangle valve Port and spool displacement adopts electric feedback. By analyzing, the paper states that six high-speed on-off valve pilot hydraulic bridge road not only can meet the requirements of differential method, but also satisfies the requirements of double valve parallel method. By the simulation analysis shows that the proportional valve based on six high-speed on-off valve pilot hydraulic bridge roads has higher control precision, faster response speed than four, and also effectively reduce the vibration of main valve.In chapter1, the current research progresses on the technology about pulse width modulation and high-speed on-off valve are reviewed. The application of proportional valve used PWM high-speed on-off valve hydraulic bridge road as pilot were introduced. In this paper, the deficiencies and technical difficulties were analyzed.In chapter2, discussing the structure and operating principle of the proportional valve based on PWM high-speed on-off valve pilot hydraulic bridge road, analyzing the advantage and disadvantage. In chapter3, the dead zone characteristics and the no-load flow characteristics of the high-speed on-off valve pilot bridge road are analyzed. The problems of low control precision and slow response speed were studied, which about four high-speed on-off valve pilot bridge road.In chapter4, the factors affecting control precision of this proportional valve is discussed. The method improving control precision is put forward, which through differential method is used by the pilot hydraulic bridge road, the rectangular valve port is adopted by main valve, and electric feedback is adopted by spool displacement. The control performance of pilot hydraulic bridge road in the differential mode is analyzed emphatically.In chapter5, the factors affecting response speed of this proportional valve is discussed. The method improving response speed is put forward, which the pilot bridge road adopts the double valve parallel mode to oil supply. The control performance of pilot hydraulic bridge road in the double valve parallel mode is analyzed emphatically. In chapter6, discussing the working principle and structure of the proportional valve based on the six high-speed on-off valve pilot hydraulic bridge roads, the no-load flow performance of six high-speed on-off pilot bridge road and the control performance of main spool movement.Finally, the main research achievements are summarized. The research conclusions and innovation points are stated, and the further research is prospected.