EVALUATION OF AN ELECTROHYDRAULIC FORGE VALVE BEHAVIOR USING A CAD PACKAGE

An electrohydraulic system of the type used to control the position of a forging press cylinder is studied analytically and experimentally. The main control component is a flow bypass valve that controls flow r ate into and out of the main hydraulic line and is of the poppet-follo wing type. The steady-state pressure/flow characteristic of the bypass valve with an existing seated poppet is compared with a new vee notch poppet design intended to improve the steady-state characteristic and hence the closed-loop press cylinder position response characteristic . Dynamic modelling of the flow bypass valve is then considered and th e transient performance is assessed for the two poppet designs and wit h the valve in an idealized circuit. The complete system dynamic model is then established and a recently developed CAD package is used to s imulate the position response of the press cylinder. Both poppet desig ns are studied, and it is deduced that there is a negligible differenc e in transient performance, attributable to unique features of the con trol system. Good comparisons between simulation and experimental resu lts were achieved.