Abstract:Since conventional direct acting electro hydraulic proportional directional valve has the limitation of small flow, and two stage electro hydraulic proportional directional valve has the limitation of complex structure, a large flow and simple structure 2D electro hydraulic proportional directional valve with position feedback was proposed. The valve coaxially consists of 2D directional valve, elastic pressure torsion coupling and the proportional electromagnet. The elastic pressure torsion coupling changes the linear movement of proportional electromagnet armature into the rotation of the spool movement, at the same time, amplifying the thrust of proportional electromagnet. Based on the operational principle of the elastic pressure torsion coupling, the mathematical model was established and the analytic equations of axial force, torque, rotation angle and deflection were deduced. Then the finite element simulation of static characteristics was performed on the platform of ANSYS Workbench 13. The analytic solutions and the simulated results are in a close agreement with the experimental results. The results indicate that with 55N input of the proportional electromagnet, through the elastic pressure torsion coupling switching, the valve has 12N·m torque output, and the linearity of the force input and the torque output is good; the spool displacement and the input displacement of elastic pressure torsion coupling are very consistent. The application of elastic pressure torsion coupling to the 2D electro hydraulic proportional direction valve is feasible.