Design and modelling of the screw cartridge rotary direct-drive servo valve

A direct-drive rotary servo valve body structure with compact structure and strong anti-pollution ability is proposed, and the jet angle of the orifice is analysed using computational fluid dynamics technology (CFD). Considering the effects of steady-state fluid torque and friction damping, a mechanical model of the valve body of the Screw Cartridge Rotary Direct-drive Servo Valve is established. Then, a MATLAB system model of the screw cartridge valve body is built, and the impact of the spool's angular acceleration, speed, and angle changes on the system are included. A Screw Cartridge Rotary Direct-drive Servo Valve testing platform is established to verify the simulation results. The results show that the Screw Cartridge Rotary Direct-drive Servo Valve has good static characteristics. Compared with the traditional servo valve, the jet angle of the Screw Cartridge Rotary Direct-drive Servo Valve is relatively small, so the hydraulic torque has a small effect on the Screw Cartridge Rotary Direct-drive Servo Valve. The maximum resistance torque of the Screw Cartridge Rotary Direct-drive Servo Valve comes from the friction resistance torque of the valve spool to the plate.