MEMORIZED-POSITION SERVOVALVE Russian patent published in 2006 - IPC F15B9/03 

FIELD: electrohydraulic systems.

SUBSTANCE: proposed servovalve contains electric motor and distributor with hydraulic spool controlled by said motor and additional ram with piston belts designed for interaction with connecting holes of distributor, thus forming ring spaces between belts and ends of distributor, two working spaces of which being connected with driven member to be controlled. Two working channels are cut in ram to provide communication of each of said working spaces with ring space arranged near them to provide equal pressure from two sides from piston belts dividing these spaces. In protection position, called emergency locking position, said piston belts overlap said working holes with clearance and as a result, leaks from working holes are directed through said clearances for draining at definite lower pressure which provides control of slow shifting of controlled member.

EFFECT: improved reliability.

7 cl, 8 dwg