Research And Application Of A New Digital Flow Control Valve

The core idea of digital hydraulic components is to load control signal on hydraulic control components directly, which achieve digital control effect. With the rapid development of electronic technology, digital valves will be more widely used. Unlike digital servo valve, digital valve can directly receive control signal from computer to precisely control hydraulic pressure,flow and so on without analog-digital conversion elements. Some advantages like small size, control easily and reliability, strong anti-oil pollution ability and so on make it widely be used in complex work environment.A new incremental digital control valve is designed in this thesis. In order to achieve better flow control characteristics, using rotary valve core not mobile orifice as flow adjustment mechanism is to receive good linearity between the valve opening degree and flow rate, based on a comprehensive analysis of the advantages and disadvantages of different forms of orifice. This structure can be obtained not only small steady flow rate, but also overcome defects of larger radial force.Choose stepper motor as control element to control the movement of valve spool considering its angular displacement is proportional to the number of pulse and design the coupling mechanism to couple the spool with the stepping motor. Research on the digital control valve static performance through theoretical analysis is conducted; the mathematical model of the digital valve is built so as to do research in the dynamic performance of digital valve. Using the computational fluid dynamics theory, simulation research of the valve's interior field is done by FLUENT,then based on the simulation results,the optimized design of the fluid pathway is carried on. Finally its application in hydraulic system is briefly presented, then the dynamic analysis and static analysis are carried out for using into the speed control system and verify its application results by testing.