Abstract: In the manufacture of vane type pumps, particularly for booster steering systems, precision assembly between the flow directing plate, sometimes referred to as a cheek plate, control plate, etc., and the cam ring is provided economically by die casting either or both components and effecting a pair of die cast tapering flat sided locating bores. One bore is elongated to allow for inaccuracies while the other is box-like in cross section. Locator pins secured in reamed bores are force fitted into the cast bores wherein the box-like bore which is dimensioned to fit a pin determines the rotational center of the components with respect to each other for exact relative positioning. The position is fixed by a pin in the elongated bore which pin can be accommodated in the elongation to compensate for spacing errors of the bores.

Abstract: A control valve for a hydraulic booster steering system provides gradual control of inlet flow to the system pump to complete cut off of output, or by throttling of inlet flow to effect a pilot stream through the pressure pump. This occurs in the neutral position of the control valve during straight ahead steering. Where flow through the pump intake feed means is thus impeded, the pump simply cavitates in a known manner and to be of a type which is suction regulated, having a check valve means at the pressure outlet side. The advantage of cutting off inlet flow to the pump during straight ahead steering, or at least throttling of such inlet flow by a constantly open throttle passage, is to save energy otherwise wasted in heating the fluid.

Abstract: An auxiliary steering flow control device having known features of a rotatable steering spindle which initially effects axial shift of a valve sleeve through a torsional stressing device acting on a pair of compressibly arched leaf springs longitudinally disposed on the axis of the steering spindle and carried in a holder within the steering spindle. The leaf springs have contiguous contacting arched surfaces on the steering spindle axis and the arched configuration effects a back to back pretensing that augments the potential energy that can be stored in the springs, particularly in arched surface contiguity with each other.

Abstract: A rotary steering control valve is provided of generally conventional construction having incorporated therein small diameter flow passages to effect throttling of return flow from a power cylinder. The throttling of exhaust from a power steering cylinder is known to be advantageous, e.g., for stifling noise, and the present invention has throttle passages incorporated directly in one of the relatively rotative valve members in such arrangement that when the valve is in neutral position for straight ahead steering, there is circulation of little pressure through the valve without throttling. However, during steering, the throttle passages are aligned in the exhaust circuit from either end of a double acting hydraulic motor so as to achieve exhaust flow throttling. The function is achieved by a novel arrangement of the coacting flow control edges and various grooves of the rotary valve plug and the encompassing sleeve which provide a multiplicity of return flow paths.

Abstract: A pressure reducing valve between a high pressure source and a steering control valve lowers the operating pressure of fluid conducted to a piston servomotor from the source by the steering control valve. A constant pressure differential across the steering control valve is maintained by the pressure reducing valve through a feedback pressure balancing arrangement to appropriately vary regulation of the feed pressure to the steering control valve.

Abstract: A plural piston pump is provided wherein the pistons are carried in bores in a body or hub on a radial plane surrounding an actuating cam and wherein a common pulsator chamber is provided comprised of axial recesses in the hub intermediate the pistons communicates with an annular channel in the hub. The arrangement provides a compact form of pump consisting essentially of a hub member externally sealed in a cylindrical housing open at its ends. The hub is provided with inlet and outlet ports, thus eliminating the need for housing ports and housing end pieces or closures and a relatively large pressure or pulsator chamber volume is formed for smoothing out pump pulsations.

Abstract: The manual force transmitted by a hand steering wheel to a fluid power steering mechanism is opposed by a reaction pressure that varies with the manual force at a proportionality factor of the operating pressure in the steering servomotor. The proportionality factor determining the reaction pressure is changeable under control of a reaction adjusting device.

Abstract: A throttle valve biased to open position by a spring is interposed in the return line of a steering control valve in a booster steering system. The essential feature of the invention is that one face of the valve is exposed to feed pressure acting against a valve opening bias spring to produce the throttling effect in accordance with construction and design of the valve and the system in which it may be used. The invention is particularly intended for use with booster steering control valves in neutral or steering position and ensures throttling of return flow to the system sump only during a steering operation. The invention is usable in steering mechanisms such as shown in the patent to Wagner et al., U.S. Pat. No. 3,964,371.

Abstract: A pair of inlet valves held closed in the neutral position of a valve actuator are opened under control of a valve operating force transmitted through a regulating spring in response to displacement of the valve actuator from the neutral position. The valve operating force applied is opposed by the pressure in a servomotor chamber to regulate the chamber pressure within a predetermined range above a limiting value of the valve operating force applied. Outlet valves are opened under a servomotor operating pressure higher than the pressure regulated by the inlet valves to control exhaust of fluid from the operating chambers.

Abstract: A piston valve construction effects leakage reduction in a control valve for hydraulic steering systems by reducing the wetted circumference of a portion of a piston valve collar with the use of radial recesses therein diverting a portion of flow therefrom to a groove of the piston valve which effects smoothing of turbulence of flow from said recesses followed by flow from said groove through a throttling gap to effect a laminar flow.

Abstract: An annular elastic valve element is deformed under fluid pressure to control flow of fluid from a piston chamber to a pressure chamber of a piston pump by separation from the peripheral wall surface of a valve seat at a location through which a passage bore extends. The valve seat overlies the outer end of the piston and its peripheral wall has reduced diameter portions spaced from the bore to accommodate elastic deformation of the valve element.

Abstract: The output pressure of a piston pump is limited by opening of a pressure responsive limiting valve discharging pump fluid in jet form through an injector into the inflow stream in the suction intake conduit to the pump. The jet is discharged in a direction opposite to the inflow stream to reduce inflow pressure for pump pressure control purposes.

Abstract: The invention provides a lightweight, economical rack steering mechanism comprising a booster pressure cylinder having a piston mounted on a toothed rack engaged by a pinion carried by an end closure element secured to the cylinder which has an end closure element at its opposite end. The rack extends in each direction out of the closure ends which effect housings for respective cylinder ends. The rack ends have connection to steering linkage means. The particularly novel feature is the use of lightweight metal, e.g., aluminum tubing, for the pressure cylinder. The mode of securing is by means of a corrugation adjacent each end of the cylinder which effects means in conjunction with locking or securing nuts and clamping or locking rings for fastening the housing ends to the cylinder. The aluminum tubing is protected against abrasive and twisting effect of nut tightening by arranging the securing nuts to abut the clamping rings which abut respective tubing corrugations nonrotatively.

Abstract: A differential pressure actuated valve is displaced from a spring-biased, stabilized position to a stabilized pump-changeover position in response to increasing pump pressure. The valve actuating pressure is varied in both directions of valve movement between the stabilized positions by variation of the restriction passage flow area through which the pressure differential is developed for actuating the valve.

Abstract: For use in an agricultural machine which is automatically steered by sensing along a row of plants, a component of the automatic steering system, namely, a comparator system is disclosed herein which utilizes hydraulic signals from independent sensors and mechanically compares such signals with each other and with a mechanical feedback responsive to the degree of angularity of the steered wheels of the vehicle. The net result of the combination and construction of the comparator system is to provide automatic steering control for a small variation of steering of left and right steering courses, for example 2 to 5 degrees, wherein any large amount of deflection of the steering wheels that may be caused by the vehicle operator taking over the steering function will not affect the automatic operation of the comparator mechanism nor will the comparator mechanism have any response thereto.

Abstract: An enclosure means for a cylinder end of a rack steering mechanism is provided comprising a bearing within the cylinder end for slidably supporting a rack and which is secured to the cylinder by nesting corrugations of the cylinder and the bearing coacting to lock the cylinder and bearing together. A sleeve of synthetic material surrounds the cylinder end and has an inwardly directed radial corrugation nesting within the corrugation of the cylinder locking it to the cylinder. The sleeve is provided with a ported through passage for equalizing air to be transferred between respective bellows at the ends of the rack which protect ball joints connecting the rack to a steering mechanism.

Abstract: Axial flow paths are established between the ring gear of a rotatable fluid displacing device and the housing of an associated control valve by radial clearance passages formed in the ring gear and spacer in axial alignment with axial flow passages of the housing through which threaded fastener shanks extend to hold the ring gear, spacer and housing assembled. The gaps between the internal teeth of the ring gear are radially extended to receive the fasteners therethrough with a close assembly clearance along radially outer portions of the fastener shanks.

Abstract: A torsion rod is provided with articulated connections at opposite ends to transmit torque between a steering spindle and the universal shaft coupling of a pump rotor in a steering control valve. The end of the torsion rod coupled to the universal shaft is received in a bore that terminates close to the driven end of the universal shaft engaged with the pump rotor, the articulated connection to the torsion rod being located at said terminal end of the bore.

Abstract: A pressure operated valve restricts outflow of fluid from a servomotor to which inflow of fluid is controlled by valve elements torsionally interconnected by a torsion bar for limited relative rotation. The pressure operated valve, mounted within one of the valve elements, is displaced by operating pressure of the inflowing fluid in the direction of the outflowing fluid to partially close a return flow valve passage and is under the bias of a spring urging the valve to a position permitting unrestricted outflow through said return flow valve passage.

Abstract: Precise control over outlet pressure as a function of valve position is obtained for operation of a servomotor by a rotary plug valve journaled at opposite ends in a control bushing having conduit channels in fluid communication with passage grooves in the plug valve to form a plurality of parallel flow paths between a pressure inlet and two directional outlets to the servomotor. The edge formed on the plug valve by a passage groove in only one of the parallel flow paths to each of the outlets is beveled to improve valve control precision.