Electrohydraulic Servo Valves

Abstract

Electrohydraulic systems use low-power electrical signals (of less than say 1 W) for precisely controlling the movements of large power hydraulic pistons and motors (which may be rated at say 10 hp—7460 W—or more). The ‘interface’ between the electrical (control) equipment and the hydraulic (power) equipment is the so-called ‘electrohydraulic servo valve’. These valves are used on systems which must respond both quickly and accurately: aircraft controls are one example and numerically controlled machine tools another, although increasingly stringent specifications for other types of plant are extending their use into most fields. Many mechanisms which use other methods of control particularly if they already employ hydraulics could benefit from incorporating electrohydraulic techniques.