Simulation And Experimental Study Of Pilot Proportional Pressure Reducing Valve

The pilot proportional pressure reducing valve is an important control element in the pressure type electro-hydraulic proportional control system.It realizes the transformation function of high pressure input to low pressure output in the system.The characteristics of proportional pressure reducing valve determines the quality of electro-hydraulic proportional control system.Optimizing the characteristics of proportional pressure reducing valve will help the further development of electro-hydraulic proportional control system.At present,there is still a large demand for open-loop proportional pressure relief in the market,but this proportional pressure reducing valves have shortcomings such as large initial adjustment pressure fluctuations,which can not be used in some systems with high control accuracy requirements.This deficiency seriously hinders the development of proportional pressure relief valve.In order to solve this problem,the structure and working principle of a proportional reducing valve was analyzed in this paper.The mechanical characteristics of the pilot valve core,the main valve core and the proportion electro-magnet was studied to establish the mathematical mode of the valve,so as to derive the transfer function block diagram.The results indicate that the proportional pressure reducing valve show open-loop control as a whole,but the pilot valve and main valve is closed-loop pressure control.The proportional pressure reducing valve is modeled in AMESim and its dynamic and static characteristics are simulated and analyzed.The results show that the spring stiffness,the diameter of damping hole of pilot flow stabilizer and the diameter of main valve core damping hole have significant effect on the dynamic and static characteristics of the valve.The diameter of damping hole of the pilot flow stabilizer,the diameter of damping hole of the main valve core and spring stiffness of the valve are selected as the main factors.The value of overshoot,the stabilization time and the response time are selected as the evaluation indicators.The combination of orthogonal experimental design and numerical simulation was carried out to improve the structure of the valve,so as to optimize the dynamic characteristics of the valve.The orthogonal experimental tests indicate that the optimum diameter of damping hole of the main valve core is 0.3 mm,the optimum diameter of damping hole of the pilot flow stabilizer is 0.7 mm,and the optimum spring stiffness is 2.6 N/mm.Compared with the characteristics ahead of optimization,the overshoot of proportional pressure relief valve decreases by 160.80%,though the response time and stability time slightly increases.However,it meets the requirements of use.The optimized proportional pressure reducing valve was tested by the existing test bench.Experimental results show that the optimized proportional pressure reducing valve has good steady pressure control characteristics,strong resistance to load change and small pressure overshoot.It meets the requirements of the use of new working conditions,and realizes the purpose of optimization.In this paper,the dynamic and static characteristics of proportional pressure reducing valve are studied by using principle analysis,mathematical modeling,computer simulation and orthogonal test.Its structural parameters are optimized.The research methods and results of this paper provide an important reference for the improvement of proportional valve.