Flow-forces effect on the behavior of an open center hydraulic distributor

The effect of steady-state axial flow-forces on the motion of an open center hydraulic distributor notched spool is considered. More in details, the spring driven spool centering is considered, in which undesired axial flow-forces could overcome the spring action. A steady-state analysis of the forces influencing the spool motion is reported, calculating the axial flow-force for different positions of the spool. Different notched shapes of the metering edge are considered, and an optimized solution for the notched edge of the spool is proposed at last