| The electro-pneumatic servo-valve is the key element in pneumatic servo-control system. The performance characteristics of electro-pneumatic servo-valve directly affect the performance of the whole pneumatic servo-control system. As high-pressure pneumatics can improve dynamic performance of the pneumatic system, enhance systemic speed and miniaturize components, it is applied more and more widely nowadays. Therefore, research and development of high-pressure electro-pneumatic servo-valve is of significant practical.The working pressure of high-pressure electro-pneumatic servo-valve is 5.0MPa in this paper, which is 5 times as existing pneumatic servo-valve. It belongs to high-pressure pneumatic.In the paper, composing principle and working principle of servo-valve are generally analyzed. The general structure of servo-valve is accomplished. It includes the general structure and mainly dimension of spool, the form of port and the choice of proportional magnet. In order to get excellent pressure-flow characteristic, two kinds of spool structure and dimension are emphatically designed so as to contrast. In the process of designing, it widely uses dimensionless method, and the intuitionistic result is displayed in graph mostly.Based on the general structure designing, main flow passage of electro-pneumatic servo-valve is built with SolidWorks. Then by dint of FLUENT, emulate the inner flow field of the servo-valve for different structure. The work easily realize the inner flow condition of valve visually, especially the distribution of pressure and velocity field. By contrast, a preferably project is confirmed.Finally, the force of spool is analyzed in detail, such as steady aerodynamic force, transient aerodynamic force and viscosity friction. Moving equation of the spool is worked out based on before-mentioned force, electromagnetic driving force and spring force. Then time domain simulation model is built in Simulink, dynamic simulations for turning on the spool are accomplished. The results indicate that this servo-valve has good opening performance.This article accomplishes theoretical research of electro-pneumatic servo-valve. The results have certain guiding significance for manufacturing the sample and experimental study. |
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