Flow-Force Analysis in a Hydraulic Sliding-Spool Valve

Original scientific paper The necessary forces for the control of a hydraulic sliding-spool valve are normally determined by the stationary axial momentum forces of the oil flow through a valve. These forces increase with an increase in the volume flow and the pressure difference. Because of the limited actuating-force potential of normal electromechanical actuators, the direct actuation of conventional valves is limited to small dimensions of valves. To make possible the use of directly actuated valves also for higher hydraulic power and to utilize the direct valve actuation also for higher flows and pressures, the flow forces acting on the valve piston in the axial direction must be compensated. This is possible with an appropriate flow stream of fluid through the valve through which the axial component of the flow forces in a conventional valve is reduced. This research work presents an analysis and compensation of the flow forces through an appropriate construction of a hydraulic piston valve of nominal size 6.