ELECTROHYDRAULIC POWER DRIVE Russian patent published in 1995 - IPC

FIELD: aeronautical engineering. SUBSTANCE: electrohydraulic power drive has four-passage servo unit 1 with rigid connection of outlet links of passages, distributing spool valves 2, feedback transmitters 3, two-chamber power hydraulic cylinder 4 and feedback transmitter 5. Hydraulic motor 12 of each passage has piston 15 provided with rubber sealing ring 16 received by groove 17. Pistons 15 of adjacent passages of servo unit 1 are connected by single rod 20 through separating sealing bush 22. When distributing spool valves 2 are set in motion, working fluid is fed to chambers of power hydraulic cylinder 4; piston stroke of this cylinder is determined by ratio of control signal to rate of change of feedback transmitters 5. Change in pressure difference has no effect on position of sealing ring 16 in groove 17 which remains pressed to one side of groove 17 at all times. EFFECT: improved dynamic characteristics in field of small input control signals, reduction of mass and overall dimensions. 1 dwg