Abstract: A power steering system which minimizes control flow supplied to a valve mechanism when a steering assist force is not required and thereby reduces energy loss and which also prevents a deterioration in steering feeling occurring when the control flow changes. A valve mechanism V is made up of a power cylinder control valve for controlling a control flow and distributively supplying it to a power cylinder Q and a bypass control valve for bypassing the two pressure chambers of the power cylinder C; the bypass control valve is normally closed, but while the control flow Q is being increased from a minimum flow Q.sub.1 to a flow Q.sub.2 required for an assist force the bypass control valve opens and bypasses the two pressure chambers of the power cylinder C so that the pressure difference between the pressure chambers rises more gently than the control flow and the driver does not experience a feeling of the steering wheel suddenly being taken over.

Abstract: A steering system (10) for a vehicle includes inner and outer valve members (40 and 42) which are rotatable relative to each other to port fluid to a vehicle power steering motor (31). A torsion bar spring (102) is connected with the inner and outer valve members (40 and 42) to resist relative rotation between the valve members during operation of the steering system (10). A torsion tube spring (202) has a first end portion (206) connected with an outer valve member (42) and a second end portion (210). The second end portion (210) of the torsion tube spring (202) is connected with a clutch (212). The clutch (212) is operable from a disengaged condition to an engaged condition to connect the second end portion (210) of the torsion tube spring (202) with the inner valve member (40). Connecting the second end portion (210) of the torsion tube spring (202) with the inner valve member (40) increases resistance to relative rotation between the inner and outer valve members (40 and 42).

Abstract: A power steering system with which no deterioration in steering feeling occurs when a control flow of working fluid changes. A valve mechanism V is made up of a power cylinder control valve CV for controlling a control flow Q and distributively supplying it to a power cylinder C and a bypass control valve BV connected in parallel with the cylinder control valve CV. The bypass control valve BV is normally closed, but while the control flow Q is increasing over a range of from a minimum flow Q.sub.1 to a maximum flow Q.sub.2 available for generating assist force the bypass control valve opens and returns a part of the control flow Q to a tank so that the pressure difference between the pressure chambers of the power cylinder C rises gently and the driver does not experience a disconcerting feeling such as one of the steering wheel suddenly being taken over.

Abstract: A compact and inexpensive fluid pressure operated torque amplifier and a power steering system incorporating such torque amplifier to eliminate the need for a separate return fluid conduit. The power steering system (10) includes a fluid pressure operated torque amplifier (12), a reduction gear unit (16) disposed within a cavity (53) of a transmission casing (14), and a steering linkage (20) for wheels. The torque amplifier includes a control valve assembly (24) disposed in a housing (22), a torque amplifier unit (32), a high torque drive shaft (58) and an output shaft (54). The output shaft of the torque amplifier serves as an input member of the reduction gear unit. The torque amplifier also includes a pressurized fluid inlet (78) provided in the housing and a return fluid outlet (61) provided in the output shaft (54), both the inlet and outlet being in communication with the cavity of the transmission casing.

Abstract: A power steering assembly (10) includes a rotatable valve core (40) which is encircled by a rotatable valve sleeve (41). The valve core (40) and valve sleeve (41) have surfaces which cooperate to direct a flow of power steering fluid during relative rotation between the valve core (40) and valve sleeve (41). A bearing assembly (100) is disposed between the valve core (40) and the valve sleeve (41) at a location adjacent to an axially outer end portion of the valve core (40). The bearing assembly (100) includes a plurality of rotatable bearing elements (124) which transmit sidewise loads between the valve core (40) and the valve sleeve (41). A bearing surface (102) is disposed on an axially inner end portion of the valve core (40). The bearing surface (102) is slidable along an inner surface area (104) on the valve sleeve (41) to transmit a sidewise load during relative rotation between the valve core (40) and the valve sleeve (41).

Abstract: A rotary control valve includes a directional control valve having a rotatable valve element for controlling the direction of fluid flow from an input passage to a pair of control ports and from the control ports to a drain passage. A pressure regulating valve is connected to a source of pilot pressure and has a valve spool for controlling the regulated pressure level of pilot fluid in the input passage. A cam is connected to the valve element for unitary rotation therewith. A spring and a plunger are disposed between the valve spool and the cam so that the valve spool is mechanically moved in a rectilinear direction by the cam in either direction from a neutral position to increase the level of the regulated pressure in the input passage proportional to the degree of rotation of the rotatable valve element.

Abstract: A steering mechanism has an input shaft 2, a steering valve 1, an output shaft 3, and a torsionally elastic element 5. The input shaft 2 has a first longitudinal axis about which the input shaft 2 is rotatable, the input shaft 2 being rotatable about the first longitudinal axis to effect the steering of a vehicle. An end of the input shaft 2 is located in the steering valve 1. The output shaft 3 has a second longitudinal axis coaxial with the first longitudinal axis and a first end adjacent the end of the input shaft 2. The torsionally elastic element 5 flexibly connects the first end of the output shaft 3 and the end of the input shaft 2 such that the input 2 and output 3 shafts are able to rotate relative to each other about the first and the second longitudinal axes, respectively, during vehicle steering. The torsionally elastic element 5 includes a plurality of separately arranged strips 8, 9, 10 & 11 located in the steering valve 1.

Abstract: In order to continuously change the transmission ratio between power-assisted steering mode and emergency steering mode and to maximize the flow of hydraulic oil in the power-assisted steering mode when the steering wheel is rapidly turned, a steering assembly is proposed which uses a common line which bypasses the metering pump, as a supply line for flow amplification during power-assisted operation and as a return line for changing the transmission ratio during emergency operation. This common line is connected to selected supply lines by way of throttles and with corresponding cylinder lines or with all cylinder lines by way of throttles. Steering devices of this type are employed in mobile equipment, in particular in slowly moving vehicles.

Abstract: A hydrostatic power steering system comprising a fluid motor (19) which receives pressurized fluid from a controller (17) in response to the rotation of a vehicle steering wheel (W). As the motor (19) or the steered wheels reach the stops, control logic (31) receives signals (37,77) representing steered wheel and steering wheel position, respectively, and generates appropriate command signals (33,27) to a pressure reducing/relieving valve (15) and to a proportional electromagnetic valve (23), respectively, closing the valve (15) somewhat, and opening the valve (23). A pressure differential is built between an additional fluid path (21) and the high pressure conduit (15c) between the controller (17) and the fluid motor (19). Pressure is communicated through the valve (23) into the conduit (51c), and back into the fluid meter (43) of the controller, preventing any further rotation thereof in response to an attempt to turn the steering wheel, thus eliminating travel limit slip.

Abstract: A motor vehicle steering apparatus contains a user-operated steering angle input system with corresponding steering shaft as well as a piston-and-cylinder unit for coupling a steering angle setting system to the steering angle input system. The hydraulic unit comprises a piston-and-cylinder unit which is disposed with its longitudinal axis running transversely of the steering shaft, and its axially moving piston is coupled mechanically with the rotatory steering shaft and divides the cylinder into two working chambers. The two cylinder halves forming working chambers are disposed on opposite sides of the steering shaft. The piston is configured as a dual piston and is coupled to the steering shaft by a coupling section lying between its ends defining the working chambers. Thereby, a steering apparatus with a compact hydraulic coupling between the steering angle input system and the steering angle setting system is provided, with the ability to rotate the steering angle input system.

Abstract: A hydraulic power steering gear (10) comprises first and second relatively rotatable valve members (40 and 42). The first valve member (40) includes a radially extending passage (64). The second valve member (42) has an arcuate cam surface (184). A detent member (220) acts between the first and second valve members (40 and 42). The detent member (220) has a curved outer surface (252). A spring (240) biases the detent member (220) radially outward against the cam surface (184). The spring (240) is disposed in the radially extending passage (64) in the first valve member (40). The detent member (220) is disposed in the arcuate cam surface (184) in the neutral condition and provides a physically perceptible indication to a driver of the vehicle of operation of the steering gear (10) between the neutral condition and the actuated condition.

Abstract: The invention relates to a hydraulic power steering system for motor vehicles, in the case of which the manual steering wheel is normally connected only by way of a control system with respect to the drive with a servomotor operating the steered vehicle wheels. In the event of a malfunctioning of the control system, a hydraulic forced coupling is automatically established between the servomotor and a hydraulic delivery unit which is constantly forcibly coupled with the steering handle, in order to form a "hydraulic linkage".

Abstract: A servo operation apparatus for a transmission comprising an input shaft to which the shift-change operation force is mechanically transmitted from a shift lever, a servo unit for boosting the shift-change operation force by feeding a working fluid, and a valve device which feeds the working fluid to, or drains the working fluid from, the servo unit depending upon the shift-change operation of the shift lever, wherein provision is made of an working fluid feed control means which feeds the working fluid in such a manner that the pressure of the working fluid in the servo unit is raised with a steep gradient in the former half until a predetermined initially raised pressure value is reached and, thereafter, is raised in the latter half with a gradient less steep than that of said former half.

Abstract: An adjusting mechanism in a control valve assembly for a power cylinder in a power-assisted steering system of an automotive vehicle for adjusting a steering effort to be applied to a steering wheel placed in a neutral position, wherein the adjusting mechanism is provided with an adjusting-element located outside a housing of the control valve assembly to be operated for adjusting a load applied to the components of the control valve assembly.

Abstract: A closed center power steering gear having a spool shaft connected to a steering wheel of the motor vehicle, a pinion head connected to steered wheels of the motor vehicle, and a control valve between a fluid accumulator and a working chamber of a steering assist fluid motor. The control valve includes a poppet on the spool shaft having closed and open positions blocking and permitting, respectively, flow from the accumulator to the fluid motor working chamber, a cam on the pinion head, a cam follower on the spool shaft, and a pressure control spring between the cam follower and the poppet. The cam, the cam follower, and the pressure control spring cooperate during relative rotation between the spool shaft and the pinion head to shift the poppet to its open position. Boost pressure in the fluid motor working chamber increases and reacts against the poppet to compress the pressure control spring and shift the poppet to its closed position.

Abstract: In order to economize the manufacture and assembly as well as reduce the expenditure of components and functionally improve a steering valve for supplying an actuator with hydraulic pressure, comprising an input shaft 2, an output shaft 3, a torsion rod 4 that is connected to one end to the input shaft 2 and with the other end to the output shaft 3, a valve sleeve 5 that surrounds the input shaft and a reaction piston 8 that may be axially moved relative to the input shaft 2, but is arranged such that it is unable to rotate and is connected to the valve sleeve 5 via an elastic rotary driver, a torsion-proof, axially elastic element 13 is arranged in the steering valve 1, with one end of said element being fastened on the input shaft 2 and its other end being fastened on the reaction piston 8.

Abstract: A hydraulic or pneumatic actuator wherein the movement of the power transfer shaft is controlled by a movable vent. The actuator is divided into two cells by a power transfer shaft to which is attached a vent follower. In an equilibrium position, the vent is closed off by the vent follower. Moving the vent location to either side of the vent follower causes fluid or gas to escape from one or the other cell. This creates a pressure difference between the cells causing the vent follower to move until it arrives at an equilibrium position. When the vent follower is caused to move the power transfer shaft also moves accordingly. In the rotary version, the vent follower operates in a wiper-type fashion. Movement of the vent follower causes the power transfer shaft to rotate. In the linear version, the power transfer shaft is attached to a piston head. The piston head is fitted into a cylinder which divides the cylinder into two hydraulic or pneumatic cells.

Abstract: A power steering control valve (22) includes inner and outer valve members (40 and 42) which are rotatable relative to each other. A force transmitting assembly (114) is operable to transmit force which resists relative rotation between the valve members. A pressure chamber (138) is connected in fluid communication with a pump (24) and controls operation of the force transmitting assembly (114). The pump (24) supplies fluid at a relatively high flow rate during operation of the pump at a low speed and supplies fluid at a relatively low flow rate during operation of the pump at a relatively high speed. A secondary valve assembly (170) is connected in fluid communication with the pressure chamber (138) and defines an orifice (182 or 184) through which pressure is vented from the pressure chamber. The secondary valve assembly (170) is operated in response to relative rotation between the inner and outer valve members (40 and 42).

Abstract: A power steering apparatus of the present invention which includes a pump, a power cylinder, a control valve, an orifice arranged in a supply passage leading an operating fluid discharged from the pump to the control valve, a flow control valve, and a switching valve. A spring chamber of the flow control valve is connected to the supply passage downstream of the orifice, and is responsive to the pressure difference across the orifice for regulating the flow rate of an operating fluid to the control valve to an almost constant flow rate. The switching valve is actuated in response to the differential pressure across the orifice for switching the communication of the spring chamber between the downstream of the orifice and the reservoir. When the differential pressure across the orifice is relatively low, the switching valve brings the spring chamber into communication with the reservoir.

Abstract: A servo-assisted rack-and-pinion steering system is provided in which the rack cooperates with a rotatable pinion. The pinion is supported in an eccentrically located opening in a circular disk rotatably mounted by rolling elements on its periphery. Pivoting movement of the pinion controls an hydraulic oil actuated servo motor. The rolling contact bearing of the disk lies in the path of flow of the hydraulic oil for the servo motor. The pinion is supported in a bearing in the opening in the disk and another bearing at an opposite side of the rack and separate from the disk.

Abstract: The invention pertains to a steering booster for delivering compressed oil to the left and right chambers (6,7) of a servo cylinder (3) via a rotary slide valve (9) with a pump (10), whereby a reaction piston (18) is arranged between an input shaft (14) and a control sleeve (15) of the rotary slide valve (9). In order to create a simply constructed hydraulic reaction device for this steering booster, the invention suggests that an electrohydraulic transformer (30) for controlling a hydraulic reaction moment in dependence on certain parameters be arranged in a line (31) between the pump (10) and the rear side of the reaction piston (18).

Abstract: A hydraulic power rack and pinion steering assembly (10) includes a valve core (98) and a valve sleeve (100) which are supported for relative rotation. A damping ring assembly (150) is interposed between the valve core (98) and the valve sleeve (100) to reduce vibrations and thereby to attenuate noise. The damping ring assembly (150) includes an inner ring (160) press fit on the valve core (98) and an outer ring (170) press fit in the valve sleeve (100). An elastomeric member (180) is disposed in the annulus between the inner ring (160) and the outer ring (170). The elastomeric member is bonded to the inner ring (160). Ribs (200) on the outer ring (170) are received in grooves (240) in the elastomeric member (180). A small gap (260) between the elastomeric member (180) and the outer ring (170) enables initial relative movement between the outer ring (170) and the inner ring (160) before the elastomeric member (180) engages the ribs (200).

Abstract: A hydraulic power rack and pinion steering assembly (10) includes a valve core (98) and a valve sleeve (100) which are supported for relative rotation. A damping ring assembly (150) is interposed between the valve parts (98, 100) to reduce vibrations and thereby to attenuate noise. The damping ring assembly (150) includes an inner ring (160) press fit on the valve core (98) and an outer ring (170) press fit in the valve sleeve (100). An elastomeric member (180) is disposed in the annulus between the inner ring (160) and the outer ring (170). The elastomeric member (180) is bonded to the inner ring (160). Ribs (210-216) on the inner ring (170) are received in grooves (270-276) in the elastomeric member (180). The ribs (210-216) sequentially engage the elastomeric member (180) upon incremental relative rotation between the valve parts (98, 100) to provide a damping effect which changes at an increasing rate as the valve parts move from the centered condition.

Abstract: A rotary slide valve (1) for power-assisted steering systems of motor vehicles contains a rotary slide (2) that is guided in a limited rotary fashion in a control box (3). Control box (3) is connected with a valve exit member (7) in a nonrotating manner. Rotary slide (2) is connected with valve exit member (7) via a torsion rod (9) and a dead-travel clutch (10). Dead-travel clutch (10) consists of a catch section piece (16) of the valve exit member (7) and of recesses (17) that are fashioned on the free end of rotary slide (2). Rotary slide (2) with its longitudinal control grooves (12, 13) and with its recesses (17) is made by way of a noncutting production process. This production process is simplified and the rotary slide valve (1) is made smaller in that the recesses (17) of rotary slide (2) are arranged in longitudinal control grooves (13) of rotary slide (2) that are open toward one end.

Abstract: The present invention is directed to a vehicular power steering system having an "open-center" control valve that has substantially zero hydraulic flow gain at zero input deflection angle and yet has minimal control orifice area. An improved valving sub-assembly is used in the control valve with functions to rapidly restore hydraulic gain at relatively small input deflection angles. The improved valving arrangement includes small transverse leakage slots formed in a valve spool that are in fluid communication with either input or return flow distribution slots. The leakage slots are configured to form parasitic flow orifices which fluidically interconnect the output slots formed in the valve sleeve and which communicate with the fluid chambers formed on opposite sides of the piston in the power cylinder. Accordingly, a selectively variable leakage path is provided across the power cylinder.

Abstract: A power steering apparatus for a motor vehicle is provided with a metering orifice arranged on a supply passage and a flow control device in parallel relation with the metering orifice. The flow control valve includes a spool and a spring and moves the spool against the force of the spring in response to the pressure difference across the metering orifice for returning an excess part of operating fluid discharged from an engine-driven pump to an intake side of the pump so as to keep the flow rate towards a power assist gear unit almost constant regardless of changes in rotational speed of the pump. A drooping device cooperating with the flow control valve is provided comprising a control orifice at the upstream of the metering orifice and a bypass valve in communication with a spring chamber of the flow control valve retaining the spring.

Abstract: A motor vehicle power steering gear having a spool shaft connected to a steering wheel, a pinion head connected to a steered wheel, a torsion bar between the spool shaft and the pinion head, a control valve for regulating a hydraulic steering assist boost pressure in response to rotation of the spool shaft from an on-center position relative to the pinion head against a restoring force of the torsion bar, and a quiet preload apparatus including a C-shaped spring around the spool shaft having a pair of resilient jaws, a drive pin on the spool shaft clamped with a preload between the resilient jaws, and a cushioned abutment on the pinion head clamped with the preload between the resilient jaws.

Abstract: A motor vehicle power steering gear having a spool shaft connected to a steering wheel, a pinion head connected to a steered wheel, a torsion bar between the spool shaft and the pinion head, a valve for regulating a hydraulic steering assist boost pressure in response to rotation of the spool shaft from an on-center position relative to the pinion head against a restoring force of the torsion bar, and a quiet preload apparatus including a C-shaped spring around the spool shaft having a pair of resilient jaws, a drive pin on the spool shaft clamped with a preload between the resilient jaws, and a cushioned abutment on the pinion head clamped with the preload between the resilient jaws. The cushioned abutment includes a pair of radial cantilever springs which flex upon engagement with corresponding ones of the resilient jaws during forced oscillation of the pinion head back and forth through the on-center relative position of the spool shaft to minimize audible noise associated with such engagements.

Abstract: A roller-contact bearing device with a reduced clearance for a power-assisted steering system having a first roller-contact bearing for absorbing axial forces exerted on a steering shaft and a second roller-contact bearing for transmitting the axial forces to a casing. The second roller-contact bearing is urged toward shaft by an spring disc to oppose the axial forces being applied to the shaft.

Abstract: A hydraulic control device comprises a valve (4) which can be moved inside a casing (1) and a stop for opening the valve at one point, the position of which may be set. The stop (6) slides in an axial housing (7) under the effect of a spring (8) and a stop screw (9). The opening position of the valve (4) may be easily set from outside the casing (1).

Abstract: A power steering control valve including relatively rotatable inner and outer valve members. A power steering resistance control system resists relative rotation between the inner and outer valve members with a force which varies as a function of variations in vehicle speed and steering demand. The power steering resistance control system includes a force transmitting member which is disposed adjacent to one end of the outer valve member. A spring force is applied against the force transmitting member urging it in a first direction along the axis of rotation of the valve members. Fluid pressure is applied against the force transmitting member to urge it in the first direction. A valve is operable to vary the fluid pressure applied against the force transmitting member. A solenoid valve controls the position of the valve as a function of vehicle speed and steering demand.

Abstract: A steering gear assembly (12) for a vehicle having steerable wheels includes a housing (14) defining a chamber (16) and a piston (18) movable through a work stroke in the chamber. The piston (18) is connected for movement with the steerable wheels of the vehicle. An actuator assembly (10) for adjusting the end-of-stroke position of the piston (18) is mounted in the housing (14) in a first orientation. The adjusting assembly (10) is removable from the housing (14), and is mountable in the housing in a second orientation opposite to the first orientation to reset the end-of-stroke position of the piston. The adjusting assembly (10) includes a pin (130) press fit in a sleeve (110) and movable in the sleeve to set the end-of-stroke position of the piston (18). The pin (130) and sleeve (110) are movable from a first position mounted in the housing (14) in a first orientation to a second position in which the pin and sleeve are mounted in the housing in a second orientation opposite to the first orientation.

Abstract: A servo control is disclosed especially for a power steering for motor vehicles. A shaft serves as an actuating member and is subdivided axially into a primary shaft and a secondary shaft. The two shaft parts are coupled elastically to one another via a torsion bar and a prestressed leg spring acting parallel thereto. Accordingly, a relative rotation adjusting a servo-valve arrangement can occur between the two shaft parts only when the shaft is loaded by a torque which exceeds the prestress of the leg spring.

Abstract: A steering system for a vehicle includes a hydraulic control valve with first and second coaxial valve members rotatable relative to each other to selectively port pressurized fluid to a vehicle power steering motor. The first valve member is connected to and rotatable with an input shaft. The second valve member is connected to and rotatable with an output member. The second valve member is axially movable relative to the first valve member between first and second positions. The input shaft and the output member are directly interconnected by the second valve member and rotatable together to effect manual steering of the vehicle when the second valve member is in its first axial position. The input shaft is rotatable relative to the output member to effect power assisted steering of the vehicle when the second valve member is in its second axial position. The second valve member is moved from its first position to its second position when the velocity of the vehicle is below a predetermined value.

Abstract: The present invention is directed to a hydro-mechanical or electro-hydro-mechanical control system utilized for positioning a mechanical device. The control system incorporates a control valve for selectively controlling the flow of hydraulic fluid to input ports of a power output transducer in response to a mechanically applied input signal. The power output transducer is then utilized to position a mechanical device. The control system is a closed loop circuit adapted to supply hydraulic fluid at a desired supply pressure to the control valve. The supply pressure is varied in relation to the absolute value of the pressure differential or load pressure exerted across the input ports of the power output transducer. A pressure regulating apparatus is provided for selectively regulating the supply pressure to a value that is nominally equal to the absolute value of the load pressure summed with a preselected supplemental pressure value across the regulating apparatus.

Abstract: The present invention is directed to a hydro-mechanical or electro-hydro-mechanical control system utilized for positioning a mechanical device. The control system incorporates an open-center control valve for selectively controlling the differential pressure applied to and the differential flow between input ports of a power output transducer in response to a mechanically applied rotational inputs. The power output transducer is then utilized to position a mechanical device. The control system is a closed loop circuit adapted to supply hydraulic fluid at a desired supply pressure to the control valve. The supply pressure is varied in relation to the absolute value of the pressure differential or load pressure exerted across the input ports of the power output transducer.

Abstract: An actuating unit for a hydraulic brake system for automotive vehicles for shortening the actuating travel of the brake power booster to pre-charge the brake system. The actuating unit includes a master cylinder and a pneumatic brake power booster connected upstream thereof. A first sealing seat (10) of a control valve (9) of the brake power booster (1), which control valve is arranged in a control housing (8), is designed separately of the control housing (8) to be slidable within limits in relation thereto. The first sealing seat (10) is held on a stop (18) on the booster housing during a predefinable actuating stroke of the control housing (8) and, respectively, of a movable wall (5) generating the boosting force. After the required actuating travel of the brake power booster, the first sealing seat (10) is carried away from the stop (18) which causes a connection between the working chamber (7) and the vacuum chamber (6).

Abstract: The present invention is directed to a hydro-mechanical or electro-hydro-mechanical control system utilized for positioning a mechanical device. The control system incorporates an open-center control valve for selectively controlling the differential pressure applied to and the differential flow between input ports of a power output transducer in response to a mechanically applied rotational inputs. The power output transducer is then utilized to position a mechanical device. The control system is a closed loop circuit adapted to supply hydraulic fluid at a desired supply pressure to the control valve. The supply pressure is varied in relation to the absolute value of the pressure differential or load pressure exerted across the input ports of the power output transducer.

Abstract: A hydraulic power steering apparatus (10) comprises a rotatable input member (31), a rotatable output member (130), and a housing supporting (11) the input member (31) and the output member (130) for rotation about an axis (45) relative to each other. A hydraulic control valve assembly (30) in the housing (11) includes a valve core (40), a valve sleeve (41) and a plurality of hydraulic seals (120-126) which block leakage of hydraulic fluid from the valve assembly (30). The hydraulic power steering apparatus (10) further includes an elastomeric damping ring (200) extending circumferentially between the valve core (40) and the valve sleeve (41). The elastomeric damping ring (200) damps vibrations of the valve core (40) relative to the valve sleeve (41), and thereby attenuates noise in the apparatus (10).

Abstract: The present invention is directed to providing an improved control valve having input and return flow passages that are hydraulically-balanced by virtue of each having a similar flow configuration for fluid flow therethrough. The input and return flow passages are formed to define input and return flow control orifices, respectively, configured for minimizing the possibility of the jet flow issuing from either input or return flow control orifices from impinging upon a surface in juxtaposition to the flow control orifice itself. Thus, the possibility of partial "flow back" into the flow control orifice is eliminated which, in turn, also prevents any significant reduction in the flow control orifice area.

Abstract: The present invention is directed to a vehicular power steering system having an "open-center" control valve that has substantially zero hydraulic flow gain at zero input deflection angle and yet has minimal control orifice area. Improved valving arrangement is desirable in that it leads to rapid restoration of hydraulic flow gain at relatively small input deflection angles. The improved valving arrangement includes small transverse leakage slots formed in a valve spool that are positioned in parallel with either input or return flow distribution slots. The leakage slots are configured to form parasitic flow orifices which fluidically interconnect the output slots formed in the valve sleeve and which communicate with the fluid chambers formed on opposite sides of the piston in the power cylinder. Accordingly, a selectively variable leakage path is provided across the power cylinder.

Abstract: An improved open-center improved valving sub-assembly of the type used for power steering systems for motor vehicles is disclosed. In particular, the improved open-center improved valving sub-assembly has a valve spool member with first and second sets of input slots and first and second sets of return slots, and a valve sleeve member with output slots and diversionary slots wherein only the output slots are coupled to a power cylinder member of a host power steering system. The output slots are linked fluidically to the first sets of input and return slots by input and return flow control orifices each comprising overlapping tangentially disposed areas therebetween. The diversionary slots are linked fluidically to the second sets of input and return slots by input and return flow selective control orifices each comprising overlapping tangentially disposed areas therebetween.

Abstract: The invention relates to a rotary hydraulic distributor comprising a primary rotary element (3) coupled to an actuating device and connected for rotation with a valve rotor, a secondary rotary element (5) coupled to a driven device and connected for rotation with a valve stator, the valve stator and the valve rotor mutually cooperating to control a double acting servomotor of the driven device, a limited relative angular displacement being permitted between primary and secondary elements (3, 5) on either side from a central rest position, and a reaction mechanism being provided in order to bias the primary element (3) toward the central rest position. According to the invention, the reaction mechanism consists of a pair of independent substantially U-shaped pistons (7) able to tilt within respectively one bore (12) of a pair of bores symmetrically provided in secondary element (5), the legs (15) of U-shaped pistons (7) engaging and biasing opposite radial ends (4) of primary rotary element (3).

Abstract: A controller (15) is provided of the type which may be utilized in a hydrostatic power steering system. The controller includes a fluid actuated displacement mechanism (21) comprising a stationary ring (47) and a moveable star (49) to meter fluid flow through the controller valving (19). A plug member (105) is operable to apply a braking force to the moveable member (49) and it cooperates with the housing (27) to define a fluid chamber (109). The housing defines a fluid passage (111, 113, 117, 119) between the fluid chamber and the controller valving (19). The controller valving in the housing defines a drain passage (95, 99, 97) to drain the fluid chamber (109) when the controller valving is in its first operating position (FIG. 4 ) and to restrict the drain and allow pressure to increase in the fluid chamber (109) when the valving is approaching its maximum displacement position (FIG. 5).

Abstract: A rotary valve (1) for hydraulic power steering of vehicles with arcuate slots (9,10) in the sleeve (2) and slots (11) in input-shaft (3) of the valve (1) where some of the slots (10) in the sleeve (2) are formed to provide hydraulic fluid return ports (13) axially of the valve (1) between the sleeve (2) and the input-shaft (3) while the axial extent of adjacent sleeve slots (10) and input-shaft slots (11) is the same at their ends remote from the return ports (13).

Abstract: A fluid control valve device includes a sleeve, a rotor, and a first recess groove. The sleeve has an inner circumferential surface in which two types of axial channel grooves communicating with an input port and a return port are formed in the circumferential direction, and left and right output ports are open in land portions between the channel grooves. The rotor is inserted in the inner circumferential surface of the sleeve so as to be rotatably held relative to the sleeve and has an outer circumferential surface in which channel grooves communicating with the axial channel grooves of the sleeve are formed in the circumferential direction at positions opposite to the land portions in which the output ports of the sleeve are open, and first and second land portions are formed at positions opposite to the channel grooves of the sleeve.

Abstract: A variable effort automotive power steering gear including an input or stub shaft, an output shaft or pinion head, a torsion bar between the stub shaft and pinion head defining an open-center position of one relative to the other, and detent reaction apparatus between the stub shaft and pinion head. The detent reaction apparatus includes a radial socket in a cylindrical wall of the pinion head, a detent groove in a stem of the stub shaft in the cylindrical wall, an insert rotatably supported in the radial socket with an eccentric bore offset from the centerline of the radial socket, and a detent element slidably supported in the eccentric bore in the insert and having a spherical end adapted to seat in the detent groove. The spherical end of the detent element is centered in the detent groove by rotating the insert until the detent element is at an innermost radial position.

Abstract: A variable effort automotive power steering gear including an input or stub shaft, an output shaft or pinion head, a torsion bar between the stub shaft and pinion head defining an open-center position of one relative to the other, and detent reaction apparatus between the stub shaft and pinion head. The detent reaction apparatus includes a radial socket in a cylindrical wall of the pinion head, a detent groove in a stem of the stub shaft in the cylindrical wall, an insert rotatably supported in the radial socket with an eccentric bore offset from the centerline of the radial socket, and a detent element slidably supported in the eccentric bore in the insert and having a spherical end adapted to seat in the detent groove. The spherical end of the detent element is centered in the detent groove by rotating the insert until the detent element is at an innermost radial position.

Abstract: A hydraulic control valve which comprises a casing having an oil inlet channel and an oil outlet channel and formed with groove portions and land portions arranged alternately in a specified direction, and a valve member having a return oil channel and attached to the casing so as to be movable relative thereto in the specified direction, the valve member having groove portions and land portions arranged alternately in the specified direction, the groove portions and the land portions of the casing being opposed to the land portions and the groove portions of the valve member respectively when the valve is in a neutral state, permitting oil supplied from the oil inlet channel to flow into the return oil channel, the valve member being movable from the neutral state relative to the casing for the land portions of the casing and the valve member to block communication betwen the oil inlet channel and the return oil channel to permit the oil supplied from the oil inlet channel to flow into the oil outlet channel

Abstract: An open-center fluid controller (15) is disclosed for controlling the flow of fluid to a steering cylinder (25). The controller includes a fluid meter (29) and valving arrangement (27), including a valve spool (43) and a sleeve (45), which define a main fluid path. The main path includes a fixed flow control orifice (86), a variable flow control orifice (87), the fluid meter (29), and a variable flow control orifice (89). In accordance with the invention, the spool and sleeve define an amplification fluid path (101), including a variable amplification orifice (99), in parallel with the main fluid path, and disposed to amplify the flow of fluid through the meter (29). In order to facilitate manual steering, the amplification orifice (99) reaches its maximum flow area when the spool and sleeve are in a normal operating position (FIG. 6). The amplification orifice then decreases and closes as the displacement between the spool and sleeve reach a maximum displacement (FIG. 7).