Study On The Pilot Valve’s Flow Characteristics Of Large Flow Proportional Directional Valve

Electro-hydraulic proportional valve is the core of electric hydraulic proportionalcontrol technology and the main power amplifier, because of its high control precision andstability, the electro-hydraulic proportional valve has begun to gradually replace thetraditional control valve. It represents the direction of fluid control technology. The pilotvalve electro-hydraulic proportional valve is the realization of electro-hydraulicproportional control technology is the key control component. Direct control typethrottling grooves spool valve is a pilot valve, its function is directly driven by theproportional electromagnet power stage spool movement, to control the flow and directionof flow to drive the main valve proportional control of oil pressure, flow rate of hydraulicsystem. Our hydraulic technology started relatively late, the key technology of throttlingspool, is still in the hands of Germany, Japan and other countries, America few producers.Domestic notches valve performance is poor, difficult to meet the requirements of themain valve to the pilot valve, the throttling grooves spool in this case study is very urgent.Effects of changes in the structural characteristics and structural parameters of the notcheson the flow area of spool and valve control characteristics are studied in the theory andexperiment.Based on the reference to domestic and foreign mature products, the pilot valveelectro-hydraulic proportional valve as the research object, using modern design methodsand means of analysis completed the following work:(1)Analysis of the working principle of the electro-hydraulic proportional valve,through the analysis and calculation for U、V-two different structure of the pilot valveflow area of the valve core structure, designed a new pilot valve head sloping groovespool and derives the formula for calculating the notches area. According to thecharacteristics of three kinds of flow control valve are analyzed.(2)Factors that affecting the different forms of valve port flow area are different,through theoretical calculation, using multiple parameters equivalent the flow area of valve. Effects of application of Matlab theoretical calculation and Simulation of flow fieldin the structure parameters and flow area on three kinds of valve port equivalent, Whichprovides the theoretical basis for the design of the valve port forward.(3)According to the three forms of Valve structure of this paper, it gives fullconsideration to the valve port machinability, the Rexroth U spool projection area equal tothe reference, design six different processing forms of valve core, through the Fluentsimulation software simulation analysis of six kinds of valve port near field, The flowfield of six kinds of valve opening of the valve port characteristics distinguish the designanalysis of the pros and cons of.(4)Relying on Yanshan University fluid laboratory PIV visual experimental set uppilot valve fluid a pump driven flow characteristics test experiment table, for a variety ofstructure of the spool valve internal flow characteristics were studied experimentally.