ABSTRACT
Fluid power systems of construction machinery or extrusion machinery require no leak electrohydraulic control valves which have capabilities of continuous and wide range flow control and quick response control under high pressure. Following the developement of a proportionally controlled seat valve<''· <2 J. <aJ with position feedback slots, authors have designed an electrohydraulic seat valve operated by a PWM switching pilot valve< 0 . The seat valve controls flow rates of 80 1/min within 10 ms in no-load condition by open roop control. The present paper discribes a flow control system with proportional controllability insensitive to load pressure disturbances. The system is named the flow sensing seat valve which consists of a combination of the seat valve
and a momentum flowmeter< 5 J. The paper shows the fundamental characteristics of the flow sensing seat valve and the analytical results of dynamics of the system.
