Abstract: In a vacuum booster for a vehicular brake, at least one of flat front attachment portion and flat rear attachment portion has a central disc portion which is concentric with a fitting cylindrical portion and plural side disc portions which are disposed around the central disc portion so as to be continuous with the central disc portion and to be spaced from each other. Bolts are inserted through at least a pair of side disc portions of the plural side disc portions.

Abstract: A pedal arrangement is provided for a motor vehicle that includes, but is not limited to a pedal module, on which at least one pedal is movably fastened. The pedal has a mount in which a push rod is movably mounted for the transmission of actuating forces which are exerted onto the pedal. The pedal module has a guide, in which the push rod is guided in a defined position such that an end region of the push rod is able to be positioned in the mount.

Abstract: This invention relates to an actuator assembly for a turbocharger pressure control valve assembly and a method of assembling a pressure control assembly of a turbocharger. The assembly comprises an actuator coupled to an actuator rod which in use is coupled to the valve assembly to control the position thereof. The actuator rod comprises an elongate member at least a portion of which is flexible. The actuator rod may be a resilient member which may be substantially straight when stressed. In use the actuator rod may extend in a substantially straight line between the actuator and the valve assembly.

Abstract: A hydraulic actuator comprises a cylinder, a piston reciprocatingly received within the cylinder, a piston rod connected to the piston and a pressure release mechanism which allows hydraulic fluid to pass from a first side of the piston to a second side of the piston when the actuator encounters shock loading. This permits the piston to move. The pressure relief mechanism includes a passageway extending from the first side of the piston to the second side of the piston and a valve member adjacent to the passageway which releasably engages the piston. The valve member has a closed position where the valve member closes the passageway and engages the piston. A resilient member biases the valve member towards the closed position. A valve member limiter limits movement of the valve member away from the closed position.

Abstract: This invention relates to an actuator assembly for a turbocharger pressure control valve assembly and a method of assembling a pressure control assembly of a turbocharger. The assembly comprises an actuator coupled to an actuator rod which in use is coupled to the valve assembly to control the position thereof. The actuator rod comprises an elongate member at least a portion of which is flexible. The actuator rod may be a resilient member which may be substantially straight when stressed. In use the actuator rod may extend in a substantially straight line between the actuator and the valve assembly.

Abstract: A power steering system, in particular for motor vehicles, includes a steering valve (15), for controlling a pressure medium for a servomotor, has two inlet seat valves (23, 24) and two outlet seat valves (25, 26), each with one closing body (31; 36). The closing bodies (36) of the outlet seat valves (25, 26) are actuatable via an actuating device as a function of a rotary motion of a steering-wheel shaft connected to an input member (10) of the steering system. The closing bodies (31) of the inlet seat valves (23, 24) are hydraulically pressure balanced with reference to a pressure of a pressure source, and by the force of locking springs (32) they keep the inlet seat valves (23, 24) closed in the neutral position of the steering valve. Each locking spring (32) is supported at one end on a closing body (31) of one of the inlet seat valves (23, 24) and on the other on the actuating device. The outlet seat valves (25, 26) are opened in the neutral position of the steering valve (15).

Abstract: A power steering system includes first and second valve members (40 and 42) which are movable relative to each other to port fluid to a vehicle power steering motor (31) and a pump (24) for providing fluid to the first and second valve members (40 and 42) and the power steering motor. A force transmitting member (116) is connected with the first valve member (40) and movable toward and away from the second valve member (42) for applying a force to resist relative movement between the first and second valve members. A fluid pressure chamber (138) receives fluid from the pump (24), the pressure of which acts on the force transmitting member (116). The first and second valve members (40 and 42) include passages for conducting fluid to the fluid pressure chamber (138). A fixed size bleed orifice (182) conducts fluid from the pressure chamber (138) to a reservoir (32). The orifice (182) restricts the flow of fluid from the chamber (138) to the reservoir (32).

Abstract: A variable effort power steering gear including a control valve substantially as described in U.S. Pat. No. 4,454,801, an electromagnetic apparatus substantially as described in U.S. Pat. No. 5,119,898 for varying the effective centering force of a torsion bar of the control valve, and a support means for a tubular spool shaft of the steering gear relative to a pinion head of the steering gear which affords the spool shaft a degree of freedom relative to the pinion head perpendicular to a lateral centerline defined by a pair of radially oriented pins connecting a valve body of the control valve to the pinion head to prevent binding between the valve body and a valve spool on the spool shaft.

Abstract: A throttle-controlled hydraulic power brake employing a pressurized fluid produced via a pump and preferably stored in an accumulator for enabling servo-assisted displacement of a push rod acting on the master cylinder of a brake pump (of the same type employed on vacuum-operated power brakes) subsequent to axial displacement of a second push rod controlled directly by the brake pedal. Displacement of the second push rod towards the first provides, against the action of elastic means, for opening a first face seal valve, which feeds the pressurized fluid into a variable-volume accumulating chamber, so as to displace a piston connected axially to the first push rod and defining a movable wall of the accumulating chamber, and so close the valve. Opposite displacement of the second push rod, on the other hand, provides for opening a second face seal valve connecting the accumulating chamber to a drain.

Abstract: A hydraulic booster for a master cylinder in which an inlet valve is interposed between an output pressure chamber at the back of the booster piston and an input pressure chamber connected to a pressure source. Advance of the valve piston opens the inlet valve. An outlet valve between the output chamber and an outlet chamber connected to an oil tank closes at advance of the valve piston relative to the booster piston. The booster chamber is exposed to a rear of a master cylinder operation piston. The valve piston oil feed passage connects input pressure chamber with booster chamber at opening of the outlet valve. The reaction chamber at the front surface of the booster piston is reduced in volume with the advancing movement and is connected to an accumulator making it possible to smooth initial operation of the master cylinder and reduce booster system size.

Abstract: A vacuum brake booster (12) having an input force applied to a brake pedal (20) for moving a plunger (28) to operate a control valve (24). A sleeve (98) concentric to the push rod (22) is located between the brake pedal (20) and plunger (28). A spring (94) acts on the sleeve (98) to move the plunger (28) against a stop (76) in the absence of an input force. A ramp (104) on sleeve (98) cooperates with projection (102) on said push rod (22) to define a linear dimension for the spring (94). Rotation of the sleeve (98) changes the load of the spring (94) and correspondingly the force required to initiate the operation of the control valve (24) through movement of the plunger (28).

Abstract: There is described a power booster for actuating a master brake cylinder having a booster piston which is axially movable in a cylinder bore and which, with its peripheral surface, confines a pressure chamber connectible to a hydraulic pressure source and, with an end surface, confines a booster chamber that is connectible with a pressure chamber via a first closable valve passage. Via a second closable valve passage, the booster chamber is connectible with a compensating chamber connected to an unpressurized reservoir. The compensating chamber is bounded by the peripheral surface of a reaction piston and by a sleeve that is formed fast with the housing and encompasses the reaction piston. The second valve passage is disposed in a central bore in the reaction piston terminating into the booster chamber. Arranged in the central bore is an actuating rod which carries a valve element for closing the second valve passage and which extends into the first valve passage in the booster piston.

Abstract: In a servo-valve arrangement, a control piston is displaced as a function of steering forces to be applied which control piston in its turn controls throttling places in such a manner that a piston-cylinder aggregate is acted upon with a pressure difference and produces a force assisting the steering movement. A throttling section connected in parallel with the piston cylinder aggregate includes throttling places controlled by external parameters as well as by the system pressure and makes it possible to act upon the end faces of the control piston with a pressure difference in order to permit a force opposing the respective displacement of the control piston to act on the control piston. As a result thereof, an undesired overcontrol of the servo-valve arrangement, respectively, of the steering system controlled thereby is avoided.

Abstract: A hydraulic booster device comprises a booster cylinder coupled with a rear end of a cylinder body of a master cylinder, a booster piston slidably received in a piston guide mounted in the booster cylinder and spring-biased in a retreating direction, a valve piston connected to an operating member and slidably received in the booster piston, an output hydraulic pressure chamber defined to face a back of the booster piston, an input hydraulic pressure chamber leading to a hydraulic pressure supply source, an inlet valve interposed between the input and output hydraulic pressure chambers and opened in response to the advancing operation of the valve piston relative to the booster piston, an outlet valve interposed between the output hydraulic pressure chamber and an outlet chamber leading to an oil reservoir and closed in response to the advancing operation of the valve piston relative to the booster piston, and a booster chamber facing a back of the operating piston and defined between the operating piston and

Abstract: A power steering system for automotive vehicles includes devices for decreasing reaction force and for increasing assisting force applied to the steering wheel in cases where steering operation is performed while the vehicle is stopped. The device comprises a cut-off valve and a bias spring biasing the cut-off valve upwardly. The area of the upper surface of the cut-off valve is larger than that of the lower surface thereof. Therefore, the cut-off valve can move downwardly against the biasing force of the bias spring to block fluid communication between a fluid pressure source and chambers of a power cylinder when fluid pressure exceeding a predetermined value is applied to the upper and lower surfaces of the cut-off valve.

Abstract: A cylindrical casing accommodates an operator pistion and a power piston separated by a fixed barrier which serves to define with the former a reservoir and with the latter a power chamber. A piston rod affixed to the operator piston extends through the barrier into manual brake actuating relation with the power piston. Hydraulic fluid under pressure is introduced to the reservoir from which it flows through barrier passages, past a check valve, into the power chamber and out through venting ports formed in the piston rod. To apply vehicle brakes linked to the power piston, the operator piston is manually propelled toward the barrier, and the power piston is thus forced away from the barrier by the piston rod, resulting in rapid transfer of hydraulic fluid from the reservoir to the power chamber. The venting ports then close, such that the power chamber is pressurized to exert a brake power assisting hydrostatic force on the power piston.

Abstract: A power steering control valve includes 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. The power steering resistance control system includes a force transmitting member which is disposed adjacent to one end of an 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 opposite side of the force transmitting member to urge it in the opposite direction along the axis of rotation of the valve members. A speed responsive control unit, connected with a fluid return conduit for the power steering valve, is operable to vary the fluid pressure applied against the force transmitting member as a function of variations in vehicle speed.

Abstract: A steering control piston valve has reaction chambers and respective fixed restrictor orifices having an interconnector conduit. The reaction chambers have respective inlet and outlet flow control valving which serve to permit flow from either reaction chamber to bypass the respective restrictor orifice during a steering maneuver if the steered wheels receive a road jolt. The arrangement provides for very rapid flow from the reaction chamber being decreased in volume due to the jolt force on the valve piston causing it to move oppositely to the steering direction. The flow from such reaction chamber passes to the interconnecting conduit for storage. An additional storage tank can be connected to the interconnecting conduit to increase the storage capacity if necessary. The bypassing is likewise advantageous in the event a vehicle swerves and rapid steering correction is necessary.

Abstract: There is disclosed a hydraulically operated power steering system which comprises a reciprocating-type hydraulically operated cylinder unit for moving a steering link mechanism and having first and second chambers, a reservoir containing hydraulic fluid therein, a hydraulic pump feeding the hydraulic fluid in the reservoir to the cylinder unit, a control valve unit including a line coupled to communicate the hydraulic pump, a line coupled to communicate the reservoir, a valve cylinder having passages coupled between the first and second chambers to provide fluid communication therebetween, and a valve spool slidably arranged in the valve cylinder and reciprocatingly movable in response to rotation of an input shaft, the cylinder unit including therein right and left reaction chambers to which opposite ends of the valve spool are exposed, the reaction chambers being communicated with the respective first and second hydraulic chambers through orifices, and a valve for dividing the left reaction chamber into a r

Abstract: A power assist steering assembly for a vehicle comprises a power assist actuator, a pump for supplying pressurized fluid to the power assist actuator, and a steering control valve comprising a movable valve member for controlling flow of pressurized fluid to the power assist actuator. A conduit that communicates pressurized fluid from the pump to the steering control valve comprises a restriction orifice. A conduit device controls the flow of pressurized fluid through the restriction orifice in accordance with vehicle speed. A mechanism is provided to resist movement of the valve to increase flow of pressurized fluid to the power assist actuator with a force which increases as vehicle speed increases. The mechanism comprises a first fluid chamber, a spring located in the first fluid chamber for biasing the valve member to a neutral position thereof, and a second fluid chamber the pressure in which counteracts the action of the spring.

Abstract: A hydraulic amplifier valve assembly having an input end (where, for example, a brake pedal force may be applied) and an ouput end includes a valve housing and an amplifier piston which is slidably received in the housing only along that end portion which is oriented towards the input end. The other terminal length portion of the amplifier piston which is oriented towards the ouput end continuously projects from the valve housing and carries a pressure conduit nipple and a return conduit nipple. The valve housing is a sheet metal construction formed of a plurality of interconnected elements. This housing includes an outer, rotationally symmetrical, generally cup-shaped sheet metal housing shell and a sheet metal inner cylinder sleeve which extends inside the housing shell coaxially therewith and at a radial distance therefrom, approximately over the entire length of the housing shell.

Abstract: Apparatus for controlling a steering force of a handle in an automobile having a power steering system in which a driving shaft of an auxiliary fluid pump for obtaining pressure oil for a hydraulic reaction chamber of the power steering system is made common to a driving shaft of a fluid pump for the power steering system to increase a quantity of discharge and oil pressure of the auxiliary pump. Oil pressure with respect to the hydraulic reaction chamber is controlled by the speed and steering angle of the automobile to obtain a proper steering force.

Abstract: A power steering system for a vehicle having a power cylinder to which a hydraulic fluid delivered from a pump driven by an engine is supplied through a fluid passage switching valve includes a pressure control valve provided in a branched fluid passage extending from a high pressure fluid passage between the pump and the switching valve to a reaction piston in the switching valve, and having a degree of opening controlled by a pilot pressure, and a pilot pressure control valve provided in a low pressure fluid passage having one end connected through an orifice to the branched fluid passage downstream of the pressure control valve and another end leading to a fluid reservoir.

Abstract: A booster steering valve control of the kind that comprises a pair of valve pistons reciprocal in a rotative valve body are driven by a fork shaped member at the end of a steering spindle. The fork shaped member comprises a pair of spaced actuator pins which engage in openings of the respective valve pistons. Thus, the valve body and the fork shaped member have a common axis about which the actuator pins rotate. A particular construction of the invention resides in the displacement of the actuator pins such that their axes are not in a common plane with the steering spindle axis but offset so that the surfaces of engagement between the actuator pins with the respective valve pistons and the spindle axis are coplanar. Engagement is maintained by spring bias acting on the valve pistons.

Abstract: A booster steering valve control device of the kind having a rotative valve body within a steering housing with a pair of piston valves operative upon rotation of a steering spindle is provided with reaction chambers at corresponding ends of the piston valves. The reaction chambers are isolated from an inlet chamber within the steering housing by means of closure caps. The closure caps are secured in place by a resilient clamp held by a bolt carried in a bore of the valve body in which the valve pistons are reciprocal.

Abstract: A hydraulic brake booster includes a booster piston axially slidable in a bore of a housing and delimiting therein a boosting compartment, and a brake pedal responsive operating element which partially extends into the boosting compartment to act as a plunger therein. A control valve has a valve body which is stationary relative to the housing and a valve member which is slidably received in the valve body and controls communication of a pressure chamber with sources of control fluid at reference pressure and at control pressure, the pressure in the boosting compartment being proportionate to the pressure in the pressure chamber.

Abstract: The invention relates to a steering assembly having a bidirectional servomotor of the differential piston type which is connectable to steerable wheels. A directional control valve unit has a spool valve with two collars which cooperates with the housing to form first and second end control chambers and a middle chamber. A power circuit supplies pressurized fluid equally to the end control chambers and a manually operable control pump is operable to selectively and incrementally increase and decrease the pressures in the end chambers in a push-pull mode to effect movement of the servomotor piston in either direction. The control valve has two ports connected to opposite ends of the servomotor with one port providing fixed and constant fluid communication between the first valve chamber and one side of the servomotor.

Abstract: A hydraulic power booster in a hydraulic brake system for an automatic vehicle includes a booster housing having inlet and outlet ports respectively connected to a fluid reservoir. A piston is slidably received within the booster housing and is connected with a master cylinder of the brake system. The piston is operated by the motion of a spool valve slidably disposed within the piston responsive to depression and release of the brake pedal. The spool valve is operated by a plunger interpositioned between the spool valve and the brake pedal. The plunger slidably extends through an outer cylindrical member which is received within the booster housing. The outer cylindrical member is cooperatively connected with the piston so that it can move in accordance with the movement of the piston. The plunger and outer cylindrical member are exchangeable to vary the ratio of the reaction force with respect to the boost force built up in the booster.

Abstract: A power steering control valve comprises a pair of rotatable elements respectively attached to input and to output members for controlling fluid flow toward first and second actuator chambers. A disc-shaped chamber having two end walls and a circumferential wall is defined by structure attached to one of the rotatable members. The other rotatable element is a star-shaped rotor coaxial with and rotatably mounted in the disc-shaped chamber, and includes a hub from which extends a plurality of legs cooperating with the walls of the disc-shaped chamber so as to separate the latter into a plurality of pressure chambers which are circumferentially distributed. Two consecutive pressure chambers communicate respectively with the first and second actuator chambers via first and second work passages. Two consecutive legs respectively face an inlet passage opening and an outlet passage opening.

Abstract: An open center hydraulic control valve of the type useful in automotive vehicles and elsewhere, in which the valve directs fluid from an inlet to a sump via first and second parallel passages including, respectively, a first outlet to a left turn cylinder and a second outlet to a right turn cylinder and in which closure of the first passage includes controlled closure of flow from the inlet to the first outlet and also controlled closure of the flow from the first outlet to the sump to provide a controlled reduced assist and improved steering stability particularly in and near the straight-ahead low turning effort valve condition.

Abstract: The legs of the landing gear of a semi-trailer may be automatically extended and retracted by a pneumatically operated actuator adapted to be connected to the crankshaft of the landing gear and adapted to rotate the cross-shaft of the landing gear selectively in either direction at a high or low speed. The crankshaft is rotated by gears and ratchets which are driven by pawls adapted to be reciprocated by an air-actuated cylinder and adapted to be alternately positioned in active and inactive positions. The flow of pressurized air to the cylinder is controlled by a cycle valve and an on-off valve, the latter being capable of turning off the actuator automatically when the legs are fully retracted.

Abstract: A hydraulic force multiplying device comprising a main body having inlet and outlet ports, input and output rods with one ends thereof being slidably connected with one another in the main body, an annular piston slidably engaging with the inner circumference of the main body and the outer circumference of the input rod and being associated with the output rod, two liquid chambers partitioned by the piston and connected respectively to the inlet and outlet ports, a connecting passage connecting the two liquid chambers, a valve mechanism provided between the input rod and the output rod for controlling the liquid flow passing through the connecting passage, and a by-pass passage provided between the piston and the input rod for connecting the two liquid chambers in the non-actuated condition of the device.

Abstract: A hydraulic booster comprising a booster piston, an annular piston bearing against the booster piston and a central piston which is movable within limits relative to the annular piston by the brake pedal to control flow of a pressurized fluid. The central piston and the annular piston are coupled together to move as a unit after the force of a spring is overcome. The central piston is subject to the pressure acting on the booster piston. In order to reduce the force reaction on the brake pedal, the central piston is operated by the brake pedal through a pin subjected to the pressurized fluid, the pin extending centrally through the annular piston in a sealed relationship thereto.

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 control valve arrangement for a servo-steering mechanism which includes a valve control member responsive to arbitrary steering motions of a steering wheel by executing relative movement with respect to a valve housing. The control member is subdivided into two coupling elements movable relative to each other, which coupling elements are mutually resiliently supported. One of the coupling elements is, in a geared manner, connected to the steering wheel with the other coupling element being provided with four control edges cooperating with corresponding control edges of a valve housing. Two of the control edges control a throttling of two pressure medium connections of one working pressure chamber of the servo-steering mechanism with the other two control edges controlling a throttling of two pressure medium connections of a second working pressure chamber of the servo-steering mechanism.

Abstract: A hydraulic booster including a housing provided with an inlet hydraulically connected to a pump, a drain port hydraulically connected to a reservoir and a cylindrical bore, a power piston sealingly and slidably disposed within the bore and dividing the cylindrical bore into a working chamber and a drain chamber which is in normal communication with the drain port, an input member sealingly and slidably passed through a first end wall of the bore, the input member having an inner end sealingly and slidably interposed within the power piston and a valve seat formed on the inner end fact thereof, an output member sealingly and slidably passed through a second end wall of the bore and connected to the power piston at an inner end of the power piston the output member provided therein with a passage communicating with the inlet, a poppet valve member sealingly and slidably disposed within the power piston and cooperable with the valve seat for controlling hydraulic communication between the working chamber and th

Abstract: A pressure relief valve for the working pressure of a servo-steering mechanism of a vehicle, with a pressure medium connection between a high pressure connection adapted to be placed under a working pressure and a zero connection adapted to be placed under a lower pressure, whose valve-adjusting member is retained in a normal rest position closing off the pressure medium connection during normal conditions by a control device operating as a function of an operating magnitude of the servo-steering mechanism and which upon exceeding a critical value of the operating magnitude is adapted to be displaced into a by-pass position more or less opening up the pressure medium connection; the control device thereby operates in dependence on the load of the servo-steering mechanism while the by-pass position is independent of the angle of rotation of the steering shaft of the servo-steering mechanism.

Abstract: A fluid-pressure operated servo-motor assembly transmits an effort from a pedal to a master cylinder for wheel brakes. The assembly includes in a housing, a pedal-operated input member, an output member acting on the master cylinder and a movable wall for transmitting the effort between them. The effort is augmented by fluid pressure in a boost chamber acting on the movable wall. The boost pressure is controlled by a valve in a stationary part of the housing. An operating assembly controls operation of the valve, and comprises a non-rotatable operating member, and a rotatable actuating member co-operating with the valve.To ensure positive operation of the valve, a helical engagement provided between the operating and actuating members, and the co-operation of the valve with the actuating member are arranged so that relative axial movement between the members causes rotation of the actuating member to operate the valve.

Abstract: A servo-steering mechanism for vehicles with a feedback of a load-dependent reaction moment onto the steering hand wheel by means of at least one reaction pressure cylinder connected with a working pressure chamber, in which a reaction pressure piston operating onto the steering hand wheel is adapted to be actuated in one direction of its piston axis by the working pressure and in the other direction of its piston axis is adapted to be supported at a support spring and is also adapted to come into abutment at a stop fixed relative to the reaction pressure cylinder, when the working pressure has been brought to a value corresponding to the prestress of the support spring; between its starting position with an unstressed support spring and its shut-off or turn-off position at the associated stop the reaction pressure piston thereby comes into additional abutment at least at one reducing spring counteracting the working pressure, whereby the reducing spring is adapted to be supported either directly or by way of

Abstract: A hydraulic brake booster adapted to vehicles having a manually operable control valve to control pressure increase in the booster for attaining the available braking fluid pressure in the brake wheel cylinders of the vehicles. In the booster is employed a control device to hold off a reaction force on the pedal to actuate the booster so that a properly controlled brake feel is transmitted to the vehicle operator at an initial stage of actuation of the booster. An earlier pressure rise is attained in the wheel cylinders within an otherwise vainly consumed period of time as a timelag and accordingly a safe and reliable braking operation is performed.

Abstract: A by-pass valve for servo-steering systems to turn off the working pressure in a cylinder chamber of a pressure medium cylinder, whose valve housing includes a valve connection adapted to be connected with the cylinder chamber, a valve connection adapted to be essentially pressure-relieved, and a valve seat for a check valve operatively connected between the two valve connections; the valve housing is thereby adjustable relative to the axis of a steering shaft for purposes of changing the position of its valve seat while the closure member of the check valve is thereby retained by springy means in its normal position closing-off the valve connections with respect to one another and is actuatable into its by-pass position connecting the valve connections with each other by way of a stem movable in unison with the closure member by way of a cam surface fixed for movement in unison with the steering shaft; the valve housing is thereby exclusively rotatable in relation to its valve housing axis but is immovably s

Abstract: A multiple servo system including two or more servo mechanisms, each having a pressure feed back including two pistons exposed in respective chambers interconnected by a low-pass hydraulic filter, in which the area of the two feedback piston faces differ by up to 25%. This reduces the tendency of the respective actuators to act in opposition and thus increases the service life of the system.

Abstract: A rack and pinion power steering gear assembly includes a housing with a longitudinal bore and a sleeve slidably mounted in the longitudinal bore. The rack is slidably mounted within the sleeve and cooperates with the sleeve to communicate an inlet port to either a first working chamber or a second working chamber when the rack moves from a first position to a second position. The rack and sleeve also cooperate with each other to define a pair of feedback chambers and the rack moves from a first position to communicate the inlet port with the first feedback chamber to a second position to communicate the inlet port with the second feedback chamber.

Abstract: A reaction mechanism of a hydraulic control valve including a control valve for regulating hydraulic pressure by controlling hydraulic fluid disgorged from a pump, an input member mechanically connected to the control valve and operated by a driver, the input member having a smaller diameter portion and a larger diameter portion, an annular reaction regulating member into which the smaller diameter portion of the input member is slidably inserted, a diameter of the annular member being equal to or less than the larger diameter portion of the input member, a biasing member for normally urging the annular member toward the larger portion of the input member, and a member for supplying the hydraulic pressure regulated by the control valve into an area between the annular member and the large diameter portion of the input member to displace the annular member from the larger diameter portion of the input member against the biasing member.

Abstract: A fluid operated motor amplifies input force and communicates a greater amount of output force to a reaction device. Input effort is directly proportional to the amplified output effort. A power piston residing in a cylinder bore has an input rod, having a spool valve and a reaction piston, laterally movable through a bore in the power piston. Fluid flow is metered to a working chamber by the spool valve in response to the position of the input rod. An output rod moves with the power piston to deliver an amplified force to a linkage.

Abstract: A servo valve device in a power steering apparatus of a vehicle, which has a main valve member provided with two valve chambers and disposed to rotate in response to one of the action of a fluid pressure motor supplementing manual steering torque and a manual steering torque, and which has two flap valve members respectively located in the two valve chambers and disposed to rotate in response to the other of the action of the fluid pressure motor and the manual steering torque for controlling fluid under pressure for the fluid pressure motor. The two valve chambers are formed by fluid-tightly partitioning an axial slot formed within the main valve member at a plane containing the rotational axis thereof, and the two flap valve members are integrally formed with each other.

Abstract: In a control valve assembly of the kind set forth for vehicle braking systesm a valve-operating member for operating first and second valves is guided to slide in a bore in a piston. The valve-operating member is adapted to permit the second valve to close and the first valve subsequently to open when the first piston is returned to an inoperative retracted position in response to the pressure of fluid remaining the pressure space when the applying force is relieved, the pressure space being defined between the first piston and a second piston.

Abstract: A hydraulic booster has its piston located in a normal passive position so that hydraulic fluid supplied to the cylinder through an inlet port enters the cylinder on both sides of the piston. Normally open valve means establishes communication through the piston from one side thereof to the other, and operating means is provided for closing the valve means and moving the piston past the inlet port to a position wherein hydraulic fluid flows through the inlet port into the cylinder on only one side of the piston. The normally open valve means includes an elongated valve sleeve slidably mounted in a piston bore having an enlarged intermediate portion defining a cavity surrounding the sleeve member. The sleeve member has a large external area within the cavity facing in one direction than in the other direction, and a leakage path is provided for communication of the cavity with the cylinder on one side of the piston.

Abstract: A motor vehicle fluid power circuit is disclosed which includes a primary pump, a closed center brake booster, and an open center steering valve. These components are hydraulically connected in series with the fluid flowing from the pump to the closed center brake booster and then to the open center steering valve. The brake booster includes valve means throttling fluid flow from the pump to the steering valve and maintaining the outlet pressure of the pump at at least a predetermined pressure differential above the working pressure of the brake booster under normal operating conditions in order to conserve output load requirements of the pump while assuring adequate pump pressure for brake booster actuation. In a second embodiment, a back-up pump is also provided in the circuit, and a pilot valve hydraulically disconnects the primary pump and hydraulically connects the back-up pump to the brake booster in response to a fluid pressure failure in the primary pump.

Abstract: A hydraulic power assisted steering system includes a source of pressure fluid fed to a power assist motor. Control of the steering assistance pressure is provided by a valve having two valve elements which are relatively rotatable away from a centered position, subject to restraint imposed by an elastic torque rod. The pressure fluid source has its output branched, one branch supplying the steering assistance motor through and subject to the control of the rotatable valve, and the second branch supplying detent means adapted to increasingly resist relative rotation of the two valve elements in response to increases in pressure of the fluid source. The fluid source pressure increases with increasing relative rotation of the valve elements away from their centered position. Increasing fluid source pressure ultimately effects interlocking of the valve elements when the source pressure reaches a predetermined value.