STEERING HYDRAULIC SYSTEM OF WHEELED VEHICLE Russian patent published in 1995 - IPC

FIELD: transport. SUBSTANCE: steering hydraulic system of wheeled vehicle has main four-line three-position control valve unit 16 hydraulically coupled with hydraulic tank 3 by second hydraulic line 17 and with spaces of power cylinder 9 by third and fourth hydraulic lines 18 and 19, respectively, through normally closed two-position control valve unit 20 and kinematically coupled with steering wheel 21, rod 10 of power cylinder 9 and steerable wheels 8. System has also auxiliary four-line three-position control valve unit 5, safety valve 2, reducing valve 4, two two-position control valve units 20 and 8 with drive from torque pickup 24 provided with interlock mechanism and installed on shaft of steering wheel 21, and two restrictors 11 and 12. Control valve unit 5 is controlled by pressure of working fluid and is coupled with hydraulic tank 3 by hydraulic control lines through two restrictors 11 and 17 and through normally open second two-position control valve unit 8, with power cylinder 9 through two additional holes made in power cylinder 9. These holes are open with piston 10 in neutral position. If piston is displaced, one of holes is overlapped. Control valve unit 5 is coupled with pump 3 by first hydraulic line through reducing valve 4, it is coupled directly with spaces of power cylinder by second and fourth hydraulic lines, and by third hydraulic line it is coupled with first hydraulic line of control valve unit 16. Auxiliary four-line three-position control valve unit 5 is made for connection of its first hydraulic line with third hydraulic line in neutral position; in two other positions its first hydraulic line can be connected with second or fourth hydraulic line, with two other hydraulic lines being closed. EFFECT: enhanced efficiency of operation. 1 dwg