The invention relates to a hydrostatic control unit of the metering type utilized for some automotive type power steering systems. The control unit has a valving section with inlet and outlet ports connectable to a pump and a tank and two working ports connectable to opposite sides of a bidirectional servomotor which is connectable to wheel steering linkage. A metering motor controlled by the valving section supplies and exhausts metered fluid to and from the servomotor through the two working ports of the valving section. The valving section has a single movable slide element cooperable with a stationary housing member. A gearing unit which may be of the planetary type is provided having two inputs and one output with the two inputs being connectable to the vehicle steering wheel and the metering motor input shaft and the output being connectable to the slide valve element. The steering wheel and metering motor inputs always act in opposite directions on the valve element such that a movement of the valve element away from a neutral position by the steering wheel is always followed by movement of the valve element back towards the neutral position by the shaft of the metering motor.
A positioning device for adjusting a motor vehicle operating lever with feedback from the respective position of a controllable part. At least one part is controllable by at least one operating lever in the form of a so-called side-stick. The motor vehicle steerable wheels can be, in particular, the controllable part.
A steering apparatus of both mechancial and hydraulic systems for a vehicle which devised the conventional steering box itself so as to attach a steering hydraulic valve directly to a steering case at the steering gear box, thereby being steerable by the steering gear box.
The invention relates to a steering control system for a bidirectional servomotor connectable to steerable wheels. The servomotor may be of the differential type in which a rod extending from one side of the piston thereof causes the effective areas on opposite sides of the piston to be unequal. A steering control unit controlled by a steering wheel has two motor ports connected to opposite sides of the servomotor and pump and tank ports connected to pump and tank units. The steering control unit has a metering motor controlled by the steering wheel which meters fluid to and away from only one side of the servomotor. The steering control unit has oppositely acting valves which may be throttle valves for establishing flow paths for opposite steering directions and the neutral condition.
A fluid-system control valve apparatus having an adjustable valve assembly between base passages and action passages. The valve assembly comprises a pair of interfaced valve members individually rotatable and normally in neutral relationship. One is a driver and the other a follower. Rotation of the driver alters the neutral relationship and forms fluid passages through the valve assembly. A reactive damming cavity is fed by a metered portion of fluid passing through the valve assembly and effects subsequent follow up rotation by the follower, thus reforming the aforesaid neutral relationship. Steering systems for vehicles comprise the control valve apparatus, a turntable for wheels, a hydraulic cylinder for turning the turntable, and conduits between the valve apparatus and hydraulic cylinder.
A control apparatus for controlling movement of a hydraulic actuator of a hydraulic control system associated with, for example, an off-road vehicle or a vessel. A geared transmission adapted to be connectable to a support member has rotatable input and output shafts, and a speed ratio of greater than unity and preferably as high as 5 to 10:1. A manually operated steering wheel is supported for substantially free rotation with, the input shaft. A rotatably actuated voltage generator is driven in rotation by the transmission output shaft to produce a high d.c. voltage, low current output signal which is proportional to the speed of rotation of the steering wheel while the output signal polarity is determined by the direction of movement of the steering wheel. A hydraulic valve driver transforms the d.c. output signal into a proportional pulse width modulated voltage control signal which controls position and movement of the hydraulic actuator.
