Abstract: The method comprises of gripping the component in a gripper of a work holding device mounted to a work holding spindle indexable about a first axis. Then cutting each slot of the array of slots in the bore by a series of cutting strokes of a cutting tool, with the tool mounted to a cutting spindle rotatable about a second axis substantially at right angles to and offset from the first axis. The cutting of each slot followed by indexation of the work holding spindle. During the cutting of at least one of the slots, relative movement between the component and second axis takes place due to movement of the component along the first axis or movement of the second axis in a direction substantially parallel to the first axis or both. The series of cutting strokes comprises two or more successions of progressively deeper cuts and the relative movement occurs between consecutive successions.

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 hydraulic fluid control valve (18) for a power steering gear (10) includes first and second relatively rotatable valve members (60, 62) which direct hydraulic fluid to flow between the valve members (60, 62) from inlet ports (70) to outlet ports (92). The valve members (60, 62) have radially opposed lands (71-79, 101-109) and grooves (81-89, 121-129) defining orifices (130) that enlarge and orifices (130) that constrict upon relative rotation of the valve members (60, 62) from neutral positions. A pair of the constricting orifices (130b, 130c) are located in parallel between the inlet ports (90) and the outlet ports (92). Each of those parallel constricting orifices (130b, 130c) is defined by a corresponding chamfered corner portion of a corresponding land (101, 102). The valve members (60, 62) provide back pressure at selected orifices between the outlet ports (92) and the inlet ports (90).

Abstract: A hydraulic power steering gear (10) for a vehicle comprises first and second valve members (40 and 42) which are disposed coaxial to one another and which are relatively rotatable about a first axis (38) to selectively port hydraulic fluid. The first valve member (40) has an associated axial bore (170). The axial bore (170) has a second axis (174) which extends parallel to the first axis (38). The second valve member (42) includes a cam surface (128). A plunger (200) is disposed in the axial bore (170) for movement along the second axis (174). The plunger has a detent surface (208). Springs (240) bias the plunger (200) axially toward the second valve member (42). A detent roller (220) acts between the first and second valve members (40 and 42). The detent roller (220) is located in the cam surface (128) and in the detent surface (208) in a neutral condition to provide a physically perceptible indication to a driver of the vehicle of operation between the neutral condition and an actuated condition.

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 vehicle power steering system comprising a power unit, a valve unit and a centering unit. A piston of the power unit reciprocates in a cylinder to provide power assisted steering and is engaged by a worm connected to the steering shaft for rotation in response to either the centering unit or the vehicle steering member. The valve unit is connected between the worm of the power unit and a steering shaft segment from the centering unit, and includes a rotary valve member rigidly fixed to the steering shaft segment and rotatably received in the bore of a sleeve member fixed to the worm. The sleeve member is connected to the rotary valve member through a torsion rod arranged to actuate a pair of spool valves formed by valving elements on the rotary valve member and the sleeve member.

Abstract: Within a valve housing of a power steering system, an object ring portion formed of a magnetic material and with ridges and troughs at its outer circumference is mounted to an input shaft, and a sensor including a Hall element is disposed in opposed relation to the object ring portion.

Abstract: The present invention concerns a servo valve, in particular for hydraulic power steering systems of motor vehicles, in the form of a rotary slide valve having a rotary slider and a control bushing which coaxially encloses the latter and is rotatable about a rotation axis, against spring force, relative to the rotary slider. The present invention includes a particular spring arrangement which has two helical compression springs lying in a radial plane of the rotation axis.

Abstract: In order to reduce the number of components required and increase the service life by preventing friction resulting from large-diameter seals, a steering valve (1) is provided which has a closed center for supplying hydraulic pressure to an actuator and which comprises an input shaft (2), an output shaft (3), a torsionally resilient element (11) which is connected at one end to the input shaft (2) and at the other end to the output shaft (3), a control pressure switching arrangement (4), and an axial force conversion unit (19-23), wherein at least one hydraulic line (15) guides reaction pressure in the input shaft (2).

Abstract: In a steering reaction force control arrangement for a hydraulic servo valve of a power steering system including a rotary spool rotatable received in a control sleeve and having a portion with axially extending V-shaped grooves disposed within a sleeve structure connected, by a conical engagement structure, to the control sleeve, the sleeve structure has radial bores receiving force transmitting balls which are pressed into the V-shaped grooves by a controllable hydraulic pressure so that the rotary spool can be moved relative to the control sleeve only upon the transmission of a torque sufficient to lift the force transmitting balls against the force of the hydraulic fluid by which they are pressed into the grooves.

Abstract: This invention relates to a servo valve which is constructed in the manner of a slide valve and particularly in the manner of a rotary slide valve. For changing the control characteristics the width of control gaps can be changed which exists in a normal or starting position. For this purpose, it is preferably provided that the control edges of the control gaps are aligned at least partially diagonally to the direction of the control strokes and the sliding part as well as the counter sliding part are completely or partially adjustable relative to one another transversely with respect to the direction of the control strokes.

Abstract: A rotary valve of a hydraulic power steering gear includes an input-shaft journalled within a sleeve. In the bore of the sleeve, an array of eight axially extending blind-ended slots and an array of two primary and two secondary axially extending return channels are formed. The primary return channels are diametrically opposed, and the secondary return channels are diametrically opposed. The return channels extend to at least one axial extremity of the bore to communicate hydraulic fluid to a return port. Further, the radial depth of the secondary return channels is substantially less than the radial depth of the primary return channels at or near the axial extremity.

Abstract: A hydraulic fluid control valve (18) for a power steering gear (10) includes first and second relatively rotatable valve members (60, 62) which direct hydraulic fluid to flow between the valve members (60, 62) from inlet ports (78) to return ports (108). The valve members (60, 62) define a plurality of orifices (110) that enlarge and a plurality of orifices (110) that constrict upon relative rotation of the valve members (60, 62). A pair of the constricting orifices (110b, 110c) are located in parallel between the inlet ports (78) and the return ports (108). Those orifices (110b, 110c) begin to constrict at the same time, and subsequently reach fully constricted conditions at staggered times, upon relative rotation of the valve members (60, 62) from neutral positions.

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: A power steering device capable of facilitating assembling thereof and eliminating a variation in elastic force acting on an input shaft of the power steering device. Leaf spring structures each of which includes a first leaf spring and a second leaf spring are arranged. The first leaf spring includes a spring-side support section constituted by a V- or U-shaped groove, a pair of rolling surface sections arranged so as to be contiguous to the spring-side support section and outwardly extend from both ends of the spring-side support section, a pair of support leg sections each arranged so as to be contiguous to each of the rolling surface sections and outwardly extend therefrom, and a pair of holding sections each arranged so as to be contiguous to each of the support leg sections and outwardly extend therefrom. The holding sections each are pressedly contacted with press contact surfaces or side surfaces of a spring receiving chamber, resulting in the first leaf spring being securely held.

Abstract: An object of the present invention is to provide a power steering apparatus in which its neutral rigidity can be raised by applying a preset force and which is superior in its assembly performance and productivity.To attain this object, first supporting portions are formed in a pair of spring members disposed across the input shaft, and second supporting portions are formed in the input shaft so as to oppose the first supporting portions. When the input shaft and the output shaft are rotated relative to each other so that the balls or rollers are about to slip out of the first and second supporting portions, the balls or rollers roll and move while deflecting the spring members.

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: A steering valve (30) directs hydraulic fluid from a hydraulic fluid source to a hydraulic cylinder of a steering system in a vehicle. The steering valve includes a rotatable first shaft (32) having a first face valve member (36) on an end portion of the first shaft and a rotatable second shaft (34) having a second face valve member (50) on an end portion of the second shaft. The first face valve member (36) includes a plurality of channels (40, 42) fluidly connected with the hydraulic cylinder and the second face valve member (50) includes a plurality of passages (54, 56) fluidly connected with the hydraulic fluid source. A rotatable intermediate disk (70) is located between the first and second face valve members (36, 50). The intermediate disk (70) includes a plurality of axially extending bores (80a-80d) for fluidly connecting the plurality of channels (40, 42) with the plurality of passages (54, 56).

Abstract: A rotary slide steering valve (1) for supplying an actuator with hydraulic pressure, has an input shaft (2), an output shaft (3), a centering spring element (4) connected to the input shaft (2) and to the output shaft (3) and a valve element. The valve element comprises at least two elements that can be turned relative to one another and comprise control bores for supplying and returning a hydraulic medium as well as a hydraulic medium line to and a hydraulic medium return line from both sides of the actuator. All control bores of the valve element which are assigned to one another are exclusively arranged within a region of opposing end faces of the input shaft (2) and the output shaft (3) and directly connected to pressure medium connections on a housing side of the rotary slide steering valve. The input shaft (2) and the output shaft (3) comprise a disk-shaped widening (11, 12) within the region of the opposing end faces. Control recesses (15, 16, 17, 18) are arranged on the opposing end faces.

Abstract: A control valve (10) controls fluid flow between a pump (34) and a motor (20) in a hydraulic power assist steering system (12) for a vehicle having steerable wheels. The control valve (10) includes a valve core (40) and a valve sleeve (50) supported for relative rotation. The control valve (10) has an inlet port (80) for receiving fluid from the pump (34) and a return passage (100) for directing fluid from the control valve to the pump (34). The control valve (10) has a first motor port (84) for enabling fluid flow between the control valve and the motor (20). First and second closing orifices (1A-L, 2A-L) are in series between the first motor port (84) and the return passage (100). A third closing orifice (2-L) is located between a second motor port (86) and the return passage (100). The orifice (1A-L) is a relatively high pressure orifice and the orifice (2A-L) is a relatively low pressure orifice.

Abstract: A vehicle steering apparatus (10) includes a fluid motor (42) having first and second chambers (44, 46). A relatively rotatable, coaxial valve core (22) and valve sleeve (24) control the fluid pressure in the chambers (44, 46). The valve sleeve (24) has first and second recesses (72a, 74a) spaced around an axis (26) on opposite sides of a fluid inlet port (70a). The valve core (22) has a third recess (80a) which communicates the port (70a) with the first and second recesses (72a, 74a) when the valve core and valve sleeve (24) are in the neutral position. The valve core (22) has first and second axially extending lands (90a, 90b) on opposite sides of the third recess (80a) and land surfaces (92a, 92b) facing the first and second recesses (72a, 74a). The valve core (22) has a first passage (100a) for communicating with the first recess (72a) and a second passage (100b) for communicating with the second recess (74a) when in the neutral position.

Abstract: A motor vehicle power steering gear has a proportional control valve with a cylindrical valve member riding rotatably on a spool shaft and connected thereto through a torsion bar. Electromagnetic apparatus for varying the magnitude of the effective restoring torque of the torsion bar comprises a stationary exciting coil, an inner pole member comprising an extension of the cylindrical valve member having a plurality of outwardly facing teeth and an outer pole member fixed on the spool shaft for rotation therewith and having an equal plurality of opposing inwardly facing teeth, the teeth defining an air gap axially beside the coil.

Abstract: A portion of an oil path between an actuator for generating steering assistance power and a pump is formed by the inside space S in a housing covering an input shaft. A bearing assembly supporting the input shaft in the inside space has a bearing joined to one of the outer and inner circumferences of a circular spacer, and is inserted between the outer circumference of the input shaft and the inner circumference of the housing via radial clearances. The displacement of the bearing assembly toward one axial direction can be restrained by the contact between the contact portion formed on the other of the circumferences of the spacer and the receiving portion formed on either the housing or the input shaft, and the bearing assembly is pressed toward one axial direction by the oil pressure in the inside space.

Abstract: A low noise rotary valve for a hydraulic power steering gear that offers flexibility in the design of its boost characteristic has inlet ports to receive hydraulic fluid from a pump, return ports to return hydraulic fluid to the pump, and cylinder ports to communicate the hydraulic fluid to left and right-hand cylinder chambers of the hydraulic power steering gear. The valve has an input-shaft with a plurality of axially extending grooves separated by lands. A sleeve that has in its bore an array of axially extending slots that circumferentially align with the lands on the input-shaft is journalled on the input shaft. The interfaces between the coacting input-shaft grooves and sleeve slots define axially extending orifices which open and close when relative rotation occurs between the input shaft and the sleeve. These orifices are ported as a network such that they form primary and secondary hydraulic Wheatstone bridges each having right and left-hand inlet orifices and return orifices.

Abstract: A low noise rotary valve for a hydraulic power steering gear offering flexibility in the design of the boost characteristic has inlet ports to receive hydraulic fluid from a pump, return ports to return hydraulic fluid to the pump, and cylinder ports to communicate the hydraulic fluid to left and right-hand cylinder chambers of the hydraulic power steering gear. The valve has an input-shaft with a plurality of axially extending grooves separated by lands. A sleeve that has in its bore an array of axially extending slots that circumferentially align with the lands on the input-shaft is journalled on the input-shaft. A torsion bar residing in a bore of the input-shaft compliantly connects the input-shaft to a driven member. The interfaces between the co-acting input-shaft grooves and sleeve slots define axially extending orifices which open and close when relative rotation occurs between the input shaft and the sleeve.

Abstract: The invention concerns a steering valve with a closed center for supplying an actuator with hydraulic pressure, the steering valve comprising an input shaft, and output shaft, a torsionally resilient element which is connected at one end to the input shaft and at the other end to the output shaft, a control pressure switching arrangement and a torque/axial force conversion unit. A spring loaded seat valve is located in a bore of the input shaft, and closes a fluid passage passing through the torsion tube. The torque/axial force convertor opens the seat valve when relative twisting of the input shaft with respect to the valve casing occurs. According to the invention, in order to improve the response dynamics of such a steering valve, the valve comprises at least one axial bore for supplying hydraulic pressure. At one end this bore is closed by a valve which is loaded by the torque/axial force conversion unit against the hydraulic pressure.

Abstract: A torsion element (1) for a steering valve is provided. The torsion element (1) comprises a torsionally elastic rod member (2) having axially opposite first and second end areas (3, 4) which are rotatable relative to one another. The rod member (2) has a circumferentially spaced plurality of radially and axially extending indentations (10) adjacent the second end area. A generally tubular, torsionally stiff sleeve member (6) encircles the rod member (2) and is fixedly attached to the first end area (4) of the rod member. The sleeve member (6) includes a circumferentially spaced plurality of radially and axially extending grooves (9) which align with and radially overlie the plurality of indentations (10) in a neutral steering condition. The sleeve member (6) further includes a circumferentially spaced plurality of radial slots (7).

Abstract: In a servo valve for hydraulic power steerings of motor vehicles which consists of a rotary spool valve having a rotary spool rotatably disposed in a control sleeve, a front end of the control sleeve and a flange structure on the rotary spool have spaced oppositely arranged faces forming a gap therebetween in which a C-shaped spring is disposed which extends around the rotary spool and has free opposite ends in engagement with pins projecting axially toward one another from the opposite faces of the control sleeve and the flange structure when both are in a center position relative to one another so as to bias the control sleeve and the flange structure into such center position with a predetermined spring force.

Abstract: A power steering control valve (10) includes inner and outer valve members (30 and 32) which are rotatable relative to each other to control fluid flow to and from a power steering motor. A damping assembly (60) is provided to damp relative movement between the inner and outer valve members (30 and 32). The damping assembly (60) includes a pair of pistons (64 and 66) which are connected with the inner valve member (30) and extend into arcuate grooves (70 and 72) in the outer valve member (32). The pistons (64 and 66) cooperate with the arcuate grooves (70 and 72) in the outer valve member (32) to form variable volume chambers (76, 78, 80 and 82). Upon relative rotation between the inner and outer valve members (30 and 32) in a first (clockwise) direction, the pistons (64 and 66) are moved relative to the outer valve member (32) to contract a pair of chambers (76 and 82) and force fluid from the contracting chambers through restrictors (84 and 90) to a return fluid flow from the power steering motor.

Abstract: A power steering apparatus in which an adjusting operation for an orifice, which is provide to optimize a steering characteristic, can be easily performed. A rotary control valve controls an amount of working oil to be supplied to a power assist cylinder in response to a relative rotation between an input member and an output member. A counter force mechanism, provided in the rotary control valve, includes a counter force plunger, a hydraulic pressure counter force chamber located on an outer side of the counter force plunger and an inside chamber located on an inner side of the counter force plunger. The counter force mechanism provides a counter force to the input member by a pressure difference between a pressure of the working oil in the hydraulic pressure counter force chamber and a pressure of the working oil in the inside chamber. A hydraulic pressure control valve is attached to the rotary control valve.

Abstract: A hydraulic power steering gear assembly includes an assembly body defining a piston chamber having opposed chamber ends with plunger passages formed in the ends, a reciprocating piston and a chamber having opposed ends and a passage extending between the piston ends, a check valve at each end of the piston passage, and a plunger assembly in each plunger passage with each assembly including a spring frictionally holding assembly in the passage and a poppet extending into the chamber to unseat a ball valve as the piston is moved toward one end of the chamber.

Abstract: A hydraulic fluid control valve (18) includes first and second valve members (60, 62) which are rotatable relative to each other about an axis (23). The valve members (60, 62) define hydraulic fluid flow orifices (110) which are spaced apart circumferentially about the axis (23). The orifices (110) are variable in size such that an orifice (110a) enlarges when a pair of adjacent orifices (110b and 110c) constrict upon relative rotation of the valve members from neutral positions. The pair of constricting orifices (110b, 110c) initially constrict at unequal rates, and subsequently constrict at equal rates until reaching fully constricted conditions.

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: In order to improve a steering valve of the relevant type such that it is of simple and economical design and without requiring increases in design length and so that it is not sensitive to rotational vibrations, a steering valve is designed to supply a servoelement with hydraulic pressure, consisting of an input shaft located in a housing, an output shaft, a centering spring element and a valve element, such that the steering valve has at least one chamber moving in a circular motion, essentially coaxial and supplied with hydraulic pressure, in which at least one piston element can move on an essentially circular path, where the chamber and/or the piston element form a portion of a bearing located between one of the shafts and the casing, or are connected axially parallel to it.

Abstract: A hydraulic fluid control valve (18) for a power steering gear (10) includes first and second relatively rotatable valve members (60, 62) which direct hydraulic fluid to flow between the valve members (60, 62) from inlet ports (70) to outlet ports (92). The valve members (60, 62) have radially opposed lands (71-79, 101-109) and grooves (81-89, 121-129) defining orifices (130) that enlarge and orifices (130) that constrict upon relative rotation of the valve members (60, 62) from neutral positions. A pair of the constricting orifices (130b, 130c) are located in parallel between the inlet ports (90) and the outlet ports (92). Each of those parallel constricting orifices (130b, 130c) is defined by a corresponding chamfered corner portion of a corresponding land (101, 102). The valve members (60, 62) provide back pressure at selected orifices between the outlet ports (92) and the inlet ports (90).

Abstract: A fluid control system (10) for a vehicle power steering mechanism having a manually driven steering member and a fluid driven driving member (16) operatively connected to steering means of the vehicle by which steerage of the vehicle is achieved, the control system (10) including a first valve (12) for metering pressurised fluid flow to the fluid operated driving member (16) in response to the force required to move the steering means when operating the manually driven steering member, the first valve (12) including at least two independent metering valve means (170, 171) each of which are simultaneously operated by the steering member to meter fluid flow to and/or from the fluid operated driving member (16) at a predefined rate, at least one of the metering valve means (170, 171) communicating independently to a drain via a second valve (14), the second valve (14) being arranged to selectively connect and disconnect said at least one of said valve means (170, 171) to the drain in response to vehicle speed.

Abstract: A rotary slide valve (1) for the power steering of motor vehicles contains a rotary distributor (4) in a valve bore (5) of a valve housing (2), which distributor is connected with a valve inlet member (23). A control bushing (7) is rotatably guided over a small angle in an axial bore (6) of the rotary distributor (4). The control bushing (7) is fixedly connected to prevent relative rotation, with a valve outlet member (18). A centering device (31) is disposed between the rotary distributor (4) and the valve outlet member (18), and contains two parts which can be rotated in respect to each other, and at least one ball (37) situated between the two parts. The one part of the centering device (31) is fixedly connected with a reaction piston (32) and fixedly connected with the rotary distributor (4) against relative rotation, but is axially displaceable.

Abstract: The power steering system for a vehicle includes a steering wheel, a torsion bar fixed to the steering wheel to rotate therewith, a hydraulic control unit for controlling hydraulic pressure generating from an oil pump in accordance with the rotation of the torsion bar, the hydraulic control unit being mounted around the torsion bar, and a power cylinder separated from the torsion bar and receiving the hydraulic pressure from the hydraulic control unit, the power cylinder having a piston meshed with a sector gear which is connected with a pitman arm.

Abstract: In a servo valve arrangement for hydraulic power assisted steering systems in motor vehicles comprising a rotary spool connected to a steering shaft and a control sleeve receiving the rotary spool so as to permit some relative rotation between the control sleeve and the rotary spool, an axial endpiece is coupled to the rotary sleeve for rotation therewith by an articulated joint structure so as to accommodate any misalignment in the steering system.

Abstract: Methods and apparatus for improving control of pressurized fluid flow through bootstrap power steering systems are disclosed. In particular, the methods include differentially measuring control pressure across internal flow control orifices as directly as possible. Differential control pressure measurements are made between Kelvin supply, or return, pressure values and a control pressure port of a control valve. In addition, methods and apparatus for improved speed sensitive control of steering assist and/or driver selectable steering effort are also disclosed. One of the methods comprises an extension of the method of differentially measuring control pressure across the internal flow control orifices wherein a range of control pressures are enabled. In addition, a method of improving low speed tactile steering feel wherein an electronically variable orifice is activated in order to provide additional fluid flow thereby increasing "on-center" hydraulic pressure gain is disclosed.

Abstract: A motor vehicle power steering gear has a proportional control valve with a cylindrical valve member riding rotatably on a spool shaft and connected thereto through a torsion rod. Electromagnetic apparatus for varying the magnitude of the effective restoring torque of the torsion rod comprises a stationary exciting coil, an extension of the cylindrical valve member having a plurality of outwardly facing teeth and an outer pole member fixed on the spool shaft for rotation therewith and having an equal plurality of opposing inwardly facing teeth, the teeth defining an air gap axially beside the coil. The cylindrical valve member is formed with a pair of sleeve surfaces for riding on the spool shaft surface with a small controlled clearance providing a hydraulic seal; and faces of the teeth of the cylindrical valve member and outer pole member are both machined after formation of the members for accurate control of the radial distance thereof from the spool shaft surface and thus of the air gap.

Abstract: A hydraulic power steering control valve (10) includes a valve core (40) and a valve sleeve (50) supported in a housing (14) for relative rotation about an axis (52). The valve core has an outer periphery (42) adjacent to an inner periphery (44) of the valve sleeve. The control valve has at least three groups of ports (PS1, PS2, PS3) extending through the valve sleeve. Each group of ports includes a fluid inlet port and first and second motor ports for communicating fluid between the control valve and a motor. The control valve is movable from a centered condition to an off-center condition to produce, at each one of the groups of ports, a respective area of high pressure fluid (HP-1, HP-2, HP-3) between the outer periphery of the valve core and the inner periphery of the valve sleeve. The areas of high pressure fluid produce a radially directed force between the valve sleeve and the valve core to increase resistance to relative rotation between the valve sleeve and the valve core.

Abstract: Hydraulic valves subjected to a pressure medium in power steering gear include a sleeve journalled on an input shaft, with the sleeve having a torsion bar connected thereto via a driven member. A method of balancing the hydraulic valve includes the steps of inserting the valve into a balanced housing, then determining the neutral position of the input shaft relative to the sleeve. The neutral position is then fixed by rotational connection of the input shaft and torsion bar. The pressure medium used to determine the neutral position is a gaseous medium, and a temporary sealing device adapted to seal the gaseous medium is in contact with the outside surface of the sleeve during determination of the neutral position.

Abstract: A rotary slide valve for power-assisted steering mechanisms of motor vehicles has two valve elements (1, 2) which are arranged to be coaxially movable within each other and are connected with each other via a torsion rod (7) and a backlash coupling (8) in such a way that they are rotatable around each other by maximally the pivot path of the backlash coupling. The inner valve element (1) is connected with a valve inlet member (3) and the outer valve element (2) with a valve outlet member (4), fixed against relative rotation. The one part of the backlash coupling (8) is formed on the radially inner valve element (1) by claws (10) which project in relation to its front face in the axial direction. The other part of the backlash coupling (8) is constituted by two pins (11) which are disposed parallel with each other in the radially outer valve element (2), whose axes (12) are located in a plane (13) extending perpendicularly in respect to the axis (14) of the rotary slide valve.

Abstract: Methods and machining apparatus for indexing and forming spool and pinion shafts for use in a rotary control valve of a power steering system are disclosed. In particular, the methods include forming a contoured spool shaft extension on an end of a spool shaft and a complementary rosette on an end of a pinion shaft, and forming spool and pinion shaft holders having complementary rosettes and contoured ends, respectively, to permit accurate mounting of the spool and pinion shafts during subsequent machine operations. The machining apparatus includes a workpiece holder which rotates the spool or pinion shaft at a predetermined speed and a cutting assembly which moves a cutting tool into and out of contact with the workpiece at three times the speed of rotation of the workpiece.

Abstract: A power steering gear including a spool shaft, a pinion head, a torsion bar between the spool shaft and the pinion head, and a rotary detent which resists twisting of the torsion bar including an annular first ball seat rotatable as a unit with a pinion head end of the torsion bar, an annular second ball seat facing the first ball seat, a plurality of detent notches in the first and second ball seats facing each other in pairs, a plurality of detent balls between the facing pairs of detent notches, a plain cylindrical sleeve around the torsion bar rigidly connected at a first end thereof to the second ball seat, a pair of radial abutments on the torsion bar near a spool shaft end thereof, and a pair of cantilever springs at a second end of the cylindrical sleeve having lateral deflection strokes perpendicular to a longitudinal centerline of the torsion bar and ramps which resiliently capture therebetween the radial abutments.

Abstract: In order to be able to more simply manufacture and center a steering valve consisting of an input shaft, an output shaft, a valve sleeve surrounding the input shaft, and a reaction arrangement to which pressure can be applied to generate a centering moment, where the steering valve can simultaneously be of a shorter configuration than a conventional steering valve, it is proposed that the hydraulic lines for the system or operating pressure, as well as for tank return, be formed between the input shaft (2) and valve sleeve (5) and that the reaction arrangement (6) exerts a radial pressure acting between the input shaft (2) and the valve sleeve (5).

Abstract: A valve for a motor vehicle power steering gear including a tubular valve body having a plurality of internal lands, a valve spool rotatable inside of the valve body having a plurality of external lands, and a plurality of metering flats on the external lands which cooperate with linear edges of the internal lands in defining a pair of series connected metering orifices in a fluid flow path through the rotary valve from a pump to a reservoir. When the series connected metering orifices are fully closed, the effective circumferential overlap between the internal and external lands which prevents leakage from the pump to the reservoir is the sum of the circumferential overlaps at the individual metering orifices.

Abstract: A power assistance steering system for use in a vehicle comprises a restricting mechanism including a cylindrical reaction piston having a reaction surface on which said reaction pressure is applied in order to cause said reaction piston to be biased downwardly, and at least one reversed V-shaped depression formed on a bottom skirt, the cylindrical reaction piston adapted to be held on the input shaft in such a way that said reaction piston can longitudinally and slidably reciprocate with respect to the input shaft, while circumferentially locked to the input shaft, and at least one semi-spherical protrusion formed on a middle end surface of said output shaft so as to be retained within the reversed V-shaped depression.

Abstract: Methods and devices for enabling simplified bootstrap hydraulic systems for use in bootstrap hydromechanical and electrohydraulic vehicular power steering systems are disclosed. A simplified bootstrap control valve is provided wherein the control valve's load circuit is not interdicted in any way. The simplified bootstrap control valve comprises a four-way control valve having input slots formed in an open-center manner, intermediate slots formed in an open-center manner, return slots formed in a closed-center manner, and a passage for picking off the pressure value present in the intermediate slots. The pressure value present in the intermediate slots is utilized for regulating pumping apparatus providing fluid to the simplified bootstrap control valve such that pressure value present in the intermediate slots is substantially maintained at a preselected value. A simplified servo motor-positive displacement pump assembly of integrated construction is also provided.