Abstract: A flow amplifier in the hydraulic steering system of a transport vehicle comprises a three-position hydraulically operated hydraulic directional control valve having a single sliding spool valve and internal hydraulic pilot lines connected, when in the crossover position, to external portholes made in a sleeve of the three-position hydraulically operated hydraulic directional control valve provided with plungers spring-loaded on their outside end faces. The flow amplifier incorporates also a pair of intensifying chokes, a air of pilot chokes, and a pair of regulating chokes made in the sliding spool valve with a possibility of varying their restriction areas along the direction of travel of the sliding spool valve.

Abstract: A hydraulically-assisted power steering assembly comprises a housing of a fluid distributor having arranged therein a control valve the central bore of which receives a steering shaft, and a servohydraulic actuator; the steering shaft, servohydraulic actuator and control valve being kinematically linked for the control valve to be capable of axial displacement when the steering shaft is turned. The kinematical linkage includes a tubular sleeve disposed inside the central bore of the control valve to rotate raltive thereto and to be fixed thereto in the axial direction, one end of the sleeve being connected to the steering shaft by way of a screw transmission.

Abstract: A hydraulic control system of a transport vehicle, wherein the flow of hydraulic fluid from the source of pressure is fed to the servomotor through a control hydraulic circuit which incorporates a fluid directional control device mechanically linked to a steering unit of a transport vehicle, a number of hydraulic lines and at least one throttle regulator, and through the actuating hydraulic circuit which incorporates a number of hydraulic lines, a throttle regulator and a discrete-type three-position fluid directional control device controlled by a pressure of the fluid flows admitted along the hydraulic lines communicated with the fluid directional control device of the control hydraulic circuit.