Abstract:Traditional direct-drive proportional directional control valve is usually actuated by the proportional solenoid. However, it is very difficult to improve the flow,because of the magnetic saturation of the proportional solenoid itself. Therefore, a new 2D electro-hydraulic proportional directional control valve was proposed. A new ball-screw type axial compression and torsion coupling as an important part was designed in this valve, which was used to amplify the driving force of the solenoid. In the theoretical analysis, the amplification coefficient was 20. It was to overcome the friction force and clamping force or other nonlinear factors. The experimental results showed that the larger helix angles and the force transfer radius of the compression and torsion coupling were, the more obvious the effect of pressure-torsion was;changing of flutter amplitude compared with flutter frequency obviously improved the static characteristics of the valve;the static characteristics of the valve were improved obviously with the increase of the helix angle and the force transfer radius. Under pressure of 7MPa, the maximum hysteresis of the valve did not exceed 3%, and the dead zone was about 0.5%;under pressure of 28MPa, the flow rate was up to 190L/min, the dead zone was about 2.8%, the maximum hysteresis was less than 5%, and pilot level leakage was about 0.2L/min. The theoretical analysis and experimental data indicated that the valve had good static characteristics compared with the traditional valve and practical engineering applications.