Abstract: A gerotor type star and ring gear machine in which control orifices in the star gear alternatively register with ports in the end wall. The star gear is formed from a series of plates and has two sets of control orifices formed therein with one set being diametrically opposed to the second set.

Abstract: The invention relates to a hydrostatic steering control unit of the type having valving for an open center neutral position which bypasses pressurized fluid from the pump to the tank when in neutral. During a turning operation with a steering wheel the open center valving is caused to close and the pressurized fluid is directed to one side or the other of a servomotor which is connected to wheels to be steered. The open center valving includes orifices in relatively rotatable elements which are aligned in the neutral position and closed to effect the turning operation. Open center valving can be the cause of noise and cavitation and such valving herein is provided with slot shaped orifices and flat generally wedge shaped throttle passages to minimize the noise and cavitation problems. The throttle passages are defined by curved bounding surfaces having rectangularly shaped outlines. A characteristic of the curved surfaces is that they are formed with exponentially shaped sections.

Abstract: The invention relates to a hydrostatic steering control unit of the type having valving for an open center neutral position which bypasses pressurized fluid from the pump to the tank when in neutral. During a turning operation with a steering wheel the open center valving is caused to close and the pressurized fluid is directed to one side or the other of a servomotor which is connected to wheels to be steered. The open center valving includes orifices in relatively rotatable elements which are aligned in the neutral position and closed to effect the turning operation. Open center valving can be the cause of noise and cavitation and such valving herein is provided with slot shaped orifices and flat generally wedge shaped throttle passages to minimize the noise and cavitation problems. The throttle passages are defined by curved bounding surfaces having rectangularly shaped outlines.

Abstract: The invention relates to hydraulic control unit for a power steering assembly. The unit is of the type having a metering motor and steering wheel actuated valves for directing metered, pressurized fluid to one selected port of a steering servo-motor and drawing fluid from the other port of the servo-motor to a tank. The invention involves a particular regulating valve for directing pressurized fluid to consumer units when the steering control is in neutral.

Abstract: 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.

Abstract: The invention relates to a hydraulic steering system of the type having a servomotor controlled by a steerable valve assembly which directs metered quantities of pressurized fluid to the servomotor and has a feedback arrangement for stopping the flow of fluid when the steering motion is stopped. The system involves an arrangement wherein the metering unit is arranged downstream from the servomotor and an auxiliary valve is provided for automatically accommodating normal conditions as well as emergency pump failure conditions and overpressure conditions caused by the servomotor reaching an extreme end position in the operation thereof.

Abstract: The invention relates to a hydrostatic steering device comprising a servo-motor operable in dependence on direction and a control device having connections for a pump, a tank and the servo-motor as well as a valve arrangement which influences the flow of pressure medium from the pump to the servo-motor and from the latter to the tank and having two valve members which are relatively movable against the force of a neutral position spring depending on the comparison of the adjustment of a steering element and the follow-up motion of a metering motor.

Abstract: The invention relates to a steering control unit for a bidirectional servomotor which is connectable to steerable wheels. A steering wheel controlled quantity setting unit of a known type has ports connectable to a pump and a return tank and two control ports through which metered quantities of fluid flow to opposite sides of the servomotor and to other parts of the apparatus for actuating the servomotor. A directional control valve for selectivity directing pressurized fluid from a power circuit to opposite sides of the servomotor is controlled by a control circuit containing the setting unit. A utility valve having the pressure regulating and control and power valve capabilities required for this type of apparatus is characterized by having only a single slide spool for performing all of these functions.

Abstract: The invention relates to hydraulic control apparatus for a servomotor of the type utilized for vehicle steering systems. Such apparatus has a control circuit controlled by a manually operated device such as a steering wheel and a power circuit connected between the servomotor and a power source such as a hydraulic pump. The power circuit includes resetting apparatus for throttling the return flow branch in a manner so that forces applied to the servomotor in the same direction as actuation are absorbed with a minimum of reactionary movement by the valves on the return flow side of the apparatus.