Abstract: The invention concerns a hydraulic steering (1) with a supply connection arrangement (P, T), a steering motor (2) and a steering unit (3) between the supply connection arrangement and the steering motor (2), the steering unit (3) having a directional section (4) and a measuring section (5), a steering valve (9) being arranged in parallel to the steering unit (3). With such a steering, it is endeavoured to achieve the best possible safety. For this purpose, it is ensured that for each steering direction the directional section (4) comprises a first outlet (A1L, A1R), which is connected to the steering motor (2) by means of a first pipe (23, 24), and a second outlet (A2L, A2R), which is connected to the steering motor (2) by means of a second pipe (25, 26), the first outlet (A1L, A1R) being, in the neutral position of the directional section (4), connected to the measuring section (5), and the first pipe (23, 24) being interruptible by means of a valve arrangement (27, 27a).

Abstract: A power steering apparatus includes a steering shaft, a hydraulic power cylinder connected to the steering shaft and having first and second hydraulic chambers, a hydraulic pump that discharges a hydraulic pressure to the power cylinder, a control valve that supplies the hydraulic pressure from the pump to the first and second hydraulic chambers selectively in response to a steering operation, a steering shaft actuation unit driven by the hydraulic pressure from the pump to apply a torque to the steering shaft, a detection unit that detects information about a vehicle, driver and/or road, and a hydraulic control unit that supplies the hydraulic pressure from the pump to either of the control valve and the steering shaft actuation unit according to the detected information and, at the supply of the hydraulic pressure to the steering shaft actuation unit, increases the hydraulic pressure supplied to the steering shaft actuation unit.

Abstract: A power steering apparatus (10) includes a first pump (24) which is continuously driven to supply fluid under pressure to a power steering motor assembly (18). A second pump (32) is driven by the engine (30) of the vehicle when a predetermined vehicle operating condition occurs. The predetermined vehicle operating condition may, if desired, be operation of the engine (30) of a vehicle at a speed which is less than a predetermined speed. A flow control valve (40) directs fluid flow from the first and second pumps to the power steering motor assembly (18) during operation of both pumps. A diverter valve (62) directs fluid from the first pump (24) along a fluid flow path which is spaced from the flow control valve (40) during operation of only the first pump. The first pump (24) may, if desired, be smaller than the second pump (32).

Abstract: A fluid system is described, which comprises first and second cylinders, each of which comprises a piston, and a first end and a second end corresponding to full stroke positions of the corresponding piston. The first ends and second ends of the two cylinders thereby define four cylinder ends. The first and second cylinders are fluidly coupled to each other via a first matched pair of cylinder ends selected from the first ends or the second ends. The system includes first and second bypass devices. The bypass devices are each configured so that when a full stroke position is occupied at a respective bypass end from among the four cylinder ends by the corresponding piston, the respective bypass device opens an outlet that allows a flow from the respective cylinder to bypass to a conduit coupled to the respective bypass end. This allows for the two cylinders to self-correct any tendency to lose synchronization with each other, and allows the system to balance pressure between the two cylinders.

Abstract: The invention discloses a vehicle steering system for motor vehicles with a steering handle operable by the driver and connected to steerable vehicle wheels in terms of effect in order to determine a direction of driving. The vehicle steering system comprises a hydraulic steering cylinder having two directions of effect, as well as a hydraulic pressure source, which applies hydraulic pressure to a steering valve. The steering valve controls the magnitude of the hydraulic pressure conveyed to the steering cylinder and determines the direction of effect of the steering cylinder. The steering valve is an electromotively driven slide valve. The steering valve comprises a rotation-translation gear in order to displace a control slide of the steering valve in a translational way.

Abstract: Disclosed is a vehicle steering system for motor vehicles with a steering handle operable by the driver and connected to steerable vehicle wheels in terms of effect in order to determine a direction of driving. The vehicle steering system includes a hydraulic working cylinder having two directions of effect, as well as a hydraulic pressure source, which applies hydraulic pressure to a valve assembly. The valve assembly controls the magnitude of the hydraulic pressure conveyed to the working cylinder and determines the direction of effect of the working cylinder. The valve assembly includes a slide valve, which is actuated by an actuator and associated with which are a pressure sensor and a travel sensor, whose signal outlets are connected to a pressure controller or a travel controller in terms of signals.

Abstract: A vehicle including a steering system for moving a pair of wheels supported by a wheel support structure relative to a vehicle structure to achieve steering of the vehicle whilst the vehicle is travelling. The system including a pressure source for providing a supply of pressurized fluid through first and second steering valves to fluid operated first and second actuators, each of which includes an actuating member. The steering valves are operator controlled to provide the pressurized fluid, at least when the steering system is in a first operating mode, from both the first steering valve to the first actuator and from the second steering valve to the second actuator to achieve steering. When the steering system is operating in a second operating mode, only one of the first and second steering valves provides pressurized fluid from the source to a respective one of the actuators to achieve steering.

Abstract: A power steering system includes first and second communication passages for providing communication between a first oil passage and a second oil passage, a third communication passage for providing communication between the first and second communication passages, a directional control valve disposed in the third communication passage, a first check valve disposed in the first communication passage for allowing flow from the first oil passage to a first connection portion only, a second check valve disposed in the first communication passage for allowing flow from second oil passage to the first connection portion only, a third check valve disposed in the second communication passage for allowing flow from a second connection portion to the first oil passage only, and a fourth check valve disposed in the second communication passage for allowing flow from the second connection portion to the second oil passage only.

Abstract: A hydraulic power steering apparatus is provided with a check valve regulating a back flow of a working fluid from a power cylinder mechanism to a hydraulic pump side. A valve element slidably accommodated within a valve body of the check valve has three guide portions protruding to an outer side in a diametrical direction. A valve internal oil path in which the working fluid circulates by a pair of guide portions adjacent in a peripheral direction is formed in the valve element. The guide portion is constituted by a slidable contact portion having a sidable contact surface surface contacted with an inner peripheral surface of the valve body, and a coupling portion coupling a base body portion and the sidable contact portion. A width (W1) in a peripheral direction of the sidable contact surface is larger than a width in the peripheral direction of the coupling portion.

Abstract: A first vehicle power steering system includes a twistable steering torsion bar, a magnet, a Hall sensor, and a valve. The steering torsion bar has a first end fixedly connected to a vehicle steering wheel. The magnet is movable in a first and an opposite second longitudinal direction with respect to the steering torsion bar and is constrained to move in the first longitudinal direction when the steering wheel is turned to the right by a driver and is constrained to move in the second longitudinal direction when the steering wheel is turned to the left by the driver. The Hall sensor has an output and is positioned proximate the magnet. The valve is operatively connected to the output. A second vehicle power steering system includes a twistable steering torsion bar, a ring-magnet support cylinder, a ring-magnet assembly, a ball-and-ramp assembly, a spring, a Hall sensor, and a valve.

Abstract: An energy attenuation device for a liquid-conveying line, comprising metal tubing disposed in the liquid-conveying line, a spring disposed in the metal tubing, and a spring-retaining device associated with the metal tubing to prevent or limit movement of the spring in the metal tubing in a downstream direction.

Abstract: A filter includes top and bottom support frames, and one or more middle support frames, which are arranged in such a manner that a second stepped area recessed by a predetermined depth from the outer circumferential surfaces of the top and bottom support frames is formed by the top and bottom support frames and the middle support frames. A pressure control valve of an electronically controllable power steering apparatus includes: a hollow valve body having a first stepped area with a predetermined depth, the first stepped area being formed on the outer circumferential surface of the valve body, where a supply port is formed; and the above-mentioned filter, the filter being fitted in the first stepped area of the valve body. The filter can minimize change of pressure at the filter area while assuring smooth supply of the hydraulic fluid, and can reduce the number of parts, the number of fabricating steps, and the material costs of such a pressure control valve.

Abstract: The invention generally relates to an improvement of conventional Hydraulically Power Assisted Steering system (HPAS-system) arranged to supply a steering assist force to the steering assembly of a vehicle as a response to a torque applied by a driver to the steering wheel. In such HPAS-systems a certain drivers torque always results in a certain assist force. The invention therefore discloses a valve that can be actuated to dynamically alter the steering assist force produced by the HPAS-system. This makes it possible to dynamically adjust the assist force so that an appropriate force may be delivered to fit the specific driving scenario.

Abstract: A vehicle steering system for motor vehicles includes a steering handle, which is connected to steerable vehicle wheels in terms of effect in order to predefine a driving direction, as well as a hydraulic working cylinder including two cylinder chambers. Further, a hydraulic pressure source is provided, which applies hydraulic pressure to a steering valve designed as a slide valve. The steering valve controls the magnitude of the hydraulic pressure that is conveyed to the cylinder chambers of the working cylinder, and a differential pressure determines the effective direction and the magnitude of the steering aid. The steering valve is a slide valve and includes a control assembly comprising a control sleeve and a control slide. The control sleeve has at least one control window, and the differential pressure in a non-linear relationship depends on the free cross-sectional surface of the control window, which is variable due to displacement of the control slide.

Abstract: A power steering apparatus includes a hydraulic power cylinder, a reversible pump including a first outlet connected with a first pressure chamber of the power cylinder through a first fluid passage, and a second outlet connected with a second pressure chamber of the power cylinder through a second fluid passage, and a motor for driving the pump. A controller controls the motor in accordance with a sensed steering force. There is further provided a connection passage connecting the first and second fluid passages together, and a closing valve disposed in the connection passage. The controller sends a first current to a coil of the valve to close the connection passage by moving an armature, to send a second current lower than the first current to the coil after the connection passage is closed, and to deenergize the coil to open the connection passage.

Abstract: A steering system has a steering control unit and a ratio adjuster for varying a flow rate amplification ratio of the steering control unit.

Abstract: A power assist steering system including a valve housing and a proportional control valve supported within the valve housing, further includes a pressure transducer arranged with respect to the proportional control valve for determining an amount of actuation of the proportional control valve. A pressure signal is sent from the pressure transducer to a control for determining an amount of current to be sent to an electromagnetic apparatus within the power assist steering system for overcoming a pull force.

Abstract: An apparatus (10) for use in turning steerable vehicle wheels (14, 16) includes a hydraulic power steering motor (12). A pump (26) is operable to supply hydraulic fluid to the power steering motor (12). A gearset (50) is connected with the engine of the vehicle and the pump (26). The gearset (50) is operable to drive the pump at a first speed during turning of the steerable vehicle wheels (14, 16) at relatively low vehicle speeds. The gearset (50) is operable drive the pump at a second speed during turning of the steerable vehicle wheels at relatively high vehicle speeds. The second speed which is less than the first speed. The gearset is a differential gear mechanism.

Abstract: A controller controls right and left wheel drive motors based on a tire angle detected by a tire angle sensor such that the angular velocities of a pair of drive wheels about the center of a turn of the vehicle are equal to each other. The controller determines a steering speed of a steered wheel at the time a steering wheel is turned, from the tire angle detected by the tire angle sensor. Based on the steering speed, the controller controls a hydraulic pressure control motor, enabling a hydraulic pump to supply working fluid at a rate corresponding to the steering speed through a priority valve to a steering cylinder. With this arrangement, the vehicle is allowed to make a smooth turn.

Abstract: A power steering pump comprises a housing that includes a bore, a fluid discharge port that supplies pumped fluid into the bore, and a fluid bypass port for recycling excess fluid to the pumping elements. The pump outlet is at one end of the bore. A flow control valve is slideably received in the bore and regulate the size of the inlet to the fluid bypass port. The pump includes a solenoid assembly that has a plunger that is operatively connected to the flow control valve through the second end of the bore opposite the pump outlet. By adjusting the magnitude of the current to the electromagnetic coil of the solenoid assembly, the position of the flow control valve is varied to increase or decrease fluid flow to the fluid bypass port and thereby regulate the output from the pump.

Abstract: A vehicle system has a steering circuit which includes a steering actuator supplied with pressurize fluid from a pressure source to turn an associated vehicle wheel to the left or right in response to the movement of the steering wheel. A feedback circuit is provided which includes a steering motor connected with the steering wheel and supplied with pressurized fluid via an electronically controlled feedback control valve means in response to signals received from a control unit to generate a steering feedback force acting on the steering wheel.

Abstract: A first fluid passage extends from a first outlet/inlet port of a hydraulic pump to a first work chamber of a power cylinder, and a second fluid passage extends from a second outlet/inlet port of the pump to a second work chamber of the power cylinder. A switch system switches the role of the first and second outlet/inlet ports in accordance with a turning direction of a steering wheel. Flow control mechanisms are respectively incorporated with the first and second fluid passages, so that a controlled flow of hydraulic fluid from the hydraulic pump to the first or second work chamber and vice versa are appropriately carried out thereby providing the driver with a comfortable steering feeling. A bypass arrangement may be provided between the first and second fluid passages to deal with a residual pressure that would be remained in the first or second work chamber when the hydraulic pump is under inoperative condition.

Abstract: A hydraulic steering apparatus with steering amount amplification is provided, wherein a metering device for supplying pressure medium to steering cylinders is actuated in accordance with an amount of rotation of the steering wheel. With the aid of a control block it is possible to deliver an additional pressure medium volume to the steering cylinders, wherein control of the control block is effected through the intermediary of a control circuit containing an effective control pressure that is substantially lower than the load pressure for transmitting the steering moment at the steering cylinder. A spring assembly for the control block is also provided, wherein two springs are arranged in parallel, one of which only takes effect following a predetermined stroke of the control element.

Abstract: A frequency suppressor for a hydraulic system is shown and described. The frequency suppressor comprises a housing that contains a substantially fixed mass of a compressible substance. The volume of the compressible substance is varied to dampen frequency disturbances in the hydraulic system.

Abstract: An assembly consists of a valve shaft, a valve member and an adjusting device which can alter the angle alignment of the valve member relative to the valve shaft.

Abstract: The invention concerns a hydraulic steering (1) with a steering unit (2) with feedback behaviour, a steering motor (8) connected to the steering unit (2) via working pipes (L, R), a steering member (6) and a feedback suppression device (9), which is located in at least one working pipe (L, R). It is endeavoured to change the feedback behaviour of such a steering in a simple manner. For this purpose, the feedback suppression device (9) has a valve arrangement (10) with hydraulic control inlet (C).

Abstract: In a power steering system comprising a power cylinder for assisting a steering power of a steering mechanism, a hydraulic pump for supplying a hydraulic pressure to the power cylinder, a first oil passage and a second oil passage connecting the power cylinder and the hydraulic pump respectively, a motor for driving the hydraulic pump, and power steering control means for calculating a command value to the motor based on the steering torque, a flow rate of the working oil supplied from a high-pressure side oil passage to a low-pressure side oil passage is restrained at the transition from the end of the steering state (lock end) of the steering mechanism to the returning. The flow-rate restraint increasingly corrects a driving current of the motor in the steering direction or limits the flow rate of the working oil.

Abstract: Disclosed is an apparatus for protecting impact to a rack bar of a power steering gearbox comprising an oil pressure cylinder, to which oil which has passed through an oil pressure pump and a rotary valve is supplied through a left port or right port, a rack bar disposed in the oil pressure cylinder and horizontally reciprocating, a piston fixed at the middle of the rack bar, a first lack bush and a second lack bush disposed at both ends of the cylinder, in which the piston moves, to close the cylinder, and bypass holes with a downward convex shape disposed at both ends of the cylinder adjacent to the first and second rack bushes, in which a part of oil pressure is released immediately before a piston of the rack bar moving by the power of oil pressure reaches a rack bush, whereby impact to the cylinder or noise is not generated.

Abstract: The flow control device comprises a supply passage (2) for supplying hydraulic fluid discharged by a pump (1) to a power steering output section (8); a variable throttle section (3) situated at an intermediate position of the supply passage (2); and a flow control valve (4) for returning the hydraulic fluid in the supply passage (2) to the pump inlet side, in accordance with a pressure differential between upstream and downstream of the variable throttle section (3). When the pump (1) is halted, the flow control valve (4) is impelled by a spring (13) and closes the variable throttle section (3). A throttle passage (51) is provided for connecting the upstream side and the downstream side of the variable throttle section with the supply passage (2).

Abstract: A method of operating a power-assisted hydraulic steering system of a motor vehicle having a hydraulic pump mechanically driven by a vehicle drive assembly, and having an additional function which reduces the amount of power assistance at a high driving speed in comparison to the assistance at a low driving speed and, in the process, simultaneously increases the quantity of hydraulic medium circulated by way of the hydraulic assistance unit of the steering gear is provided. This additional function is activated independently of the driving speed also under operating conditions which may subject the hydraulic pump to extreme stress. For example, the additional function may be activated shortly before reaching the steering end stop, which can be detected by use of an appropriately arranged steering angle sensor. An activation also is possible if steering angles which are larger than a defined limit steering angle are set for a defined time period.

Abstract: An engine driven pump 24 is connected with a power steering motor assembly 18. An electric motor 36 drives a pump 34 connected with the power steering motor assembly 18. A control apparatus 38, 44, 52, 62 and 72 effects operation of the electric motor 36 to drive the pump 34 when the power steering motor assembly 18 requires fluid in addition to fluid supplied by the engine driven pump 24.

Abstract: The present invention provides a hydraulic control valve and a power steering apparatus using the same in which chamfer portions are provided only on throttle portions between oil supply chambers and first oil feed chambers and between the oil supply chambers and second oil feed chambers, or only throttle portions between oil discharge chambers 11 and the first oil feed chambers and between the oil discharge chambers 11 and the second oil feed chambers. With this design, even if six or more oil grooves of each of a valve body and a valve spool are disposed at equal distances from one another, when the minimum flow rate to be controlled is reduced as small as possible, a distribution amount for one portion where the flow rate is controlled can be doubled as compared with a conventional structure, it is possible to stabilize the hydraulic characteristics in a region where the flow rate to be controlled is minimum, and to eliminate the discontinuity of the hydraulic characteristics.

Abstract: A power steering system includes a hydraulic power cylinder, a hydraulic pump for supplying an oil pressure to the hydraulic power cylinder, an electric motor for driving the hydraulic pump, a first detector for detecting a steering assist force to be applied to a steering wheel, a second detector for detecting an operating condition of the electric motor, and a controller. The controller includes a control section for controlling the electric motor based on the required steering assist force detected by the first detector so as to cause the hydraulic pump to produce a required oil pressure, and a determining section for determining based on the operating condition of the electric motor and the required steering assist force detected by the first detector whether or not the power steering system is abnormal.

Abstract: A thrust piece unit for rack-and-pinion steering mechanisms, which is integrated into a housing bore of the steering mechanism housing of motor vehicles, in order to keep the pinion in constant intermeshing with the rack, the thrust piece unit comprising a cylinder part, a piston part and two chambers which are matched with one another and are filled with hydraulic medium and which are connected to one another via a replenishing valve and via a throttle point, and overload protection being additionally integrated in the thrust piece unit.

Abstract: A power steering system includes a reversible-type oil pump supplying hydraulic fluid to first and second pressure chambers of a hydraulic power cylinder through first and second passages and having first and second discharge ports, and a branch passage conveying part of hydraulic fluid discharged from the discharge ports of the oil pump to the outside of the pressure chambers of the power cylinder, wherein the branch passage has a passage sectional area greater than a total leak sectional area of the oil pump.

Abstract: An electric power steering apparatus transmits a driving force of an electric motor to a steering mechanism for steering assist. The apparatus includes a torque sensor which detects a steering wheel torque; a basic assist characteristic determining section which determines a basic assist characteristic defining a basic characteristic of a motor driving target value for the steering torque; a motor driving target value determining section which determines the motor driving target value for the steering torque in accordance with a modified assist characteristic prepared by shifting the basic assist characteristic along a steering torque coordinate axis; a shift amount determining section which determines the amount of the shift from the basic assist characteristic to the modified assist characteristic on the basis of the steering torque; and a motor driving section which drives the electric motor on the basis of the motor driving target value.

Abstract: A power steering system includes first and second drain passages connected to the first and second passages, respectively, and first and second passage switching valves arranged at connections of the first and second drain passages and the first and second passages, respectively. When a hydraulic pump operates to discharge the hydraulic pressure to the first passage, the first passage switching valve provides fluid communication between pump-side and cylinder-side portions of the first passage and closes off the first drain passage. And when the hydraulic pump stops, the first switching valve provides fluid communication between the cylinder-side portion of the first passage and the first drain passage.

Abstract: One of the mode lamps 38a, 38b and 38c of the mode indicator 38 corresponding to the current steering mode is turned on yellow and the other mode lamps are turned on green or turned off, thereby indicating whether front wheels 1, 1 and rear wheels 2, 2 are at neutral. A controller 39 does not operate a mode changing valve 24 even with an instruction outputted from a mode change switch 35 when the front and rear wheels are not at neutral, and operates, in response to an instruction outputted from the mode change switch 35, the mode changing valve 24 to establish a steering mode corresponding to the instruction when the front and rear wheels are at neutral. Also, the mode indicator 38 is controlled to always indicate, as the current steering mode, one corresponding to the steering mode actually established by the mode changing valve 24.

Abstract: In a valve for a hydraulic power steering, comprising a first valve element and a second valve element which from a central position can be rotatably displaced relative to each other to a limited extent in the one or other direction in order to generate a steering assistance, it is provided that one of the valve elements can be rotatably displaced from a neutral position into the one or other direction relative to an associated shaft and that a coupling mechanism is provided which limits the displacement in rotation of the valve element relative to the shaft and urges the valve element into the neutral position.

Abstract: A power steering system for a vehicle. The system includes a hydraulic power cylinder, first and second hydraulic lines, a bypass passage through which the first and second hydraulic lines are connected with each other, and a flow passage change-over device adapted to close the bypass passage during steering assisting. A supply passage and a return passage are disposed in parallel with each other to form part of each of the first and second hydraulic lines. The flow passage change-over device is disposed in each of the first and second hydraulic lines. A differential pressure regulating valve is disposed in each of the return passages and adapted to allow hydraulic fluid to flow toward the hydraulic pressure source in a condition where pressure on side of the hydraulic power cylinder becomes higher than a set pressure or higher than pressure on side of the hydraulic pressure source.

Abstract: A bi-directional damper valve is provided for connecting to a hydraulic line, to regulate fluid flow therethrough. The damper valve includes a main valve body having a flow passage formed therethrough, and the flow passage widens at central portion of the valve body to form a central chamber, which has valve seats formed at opposite ends thereof. The main valve body also has two bypass channels formed therein, which branch off the central chamber near the valve seats, and which selectively communicate with the flow passage. The damper valve also includes two poppets, oriented facing in opposite directions in the central chamber. Each of the poppets has a hollow bore formed therethrough, to always allow fluid flow through the damper valve at a first (minimal) rate. The damper valve also includes a spring extending between the poppets, and normally biasing them against the valve seats.

Abstract: An autonomous wheeled mobile robot (1) comprising at least one wheel-driving motor, an on-board computer, means for navigation, orientation, and maneuvering in an environment with moving obstacles; a sensor system; and a wireless communication system for receiving and sending.

Abstract: A hydraulic power-assisted steering system, in particular for motor vehicles, has a hydraulic pump for generating hydraulic pressure for assisting the steering and an electromagnetic valve, in addition to a motor for driving the hydraulic pump. The hydraulic pump can be decoupled from the motor by a coupling.

Abstract: An integrated hydraulic control system includes a steering control unit and a priority flow divider integrated into a unitary casing. An interface fluidly couples the casing for the steering control unit and priority flow divider directly to a control valve casing. All hydraulic communication between the steering control unit, the priority flow divider, and the control valve are located inside the casings.

Abstract: A system and method of controlling flow outlet from a hydraulic pump. The system provides the level of flow required to execute the driver's steering commands. This method of control reduces the average torque requirement of the hydraulic pump thereby improving fuel economy by unloading the vehicle's accessory drive, while also providing the variable assist power steering feature. The Fuel Efficient Power Steering (FEPS) control algorithm is an optimal method of regulating flow by actuating the electronic flow control device in the pump assembly. This electronic flow control device allows an increase in hydraulic fluid flow to the steering gear in order to increase the provided assist and to reduce hydraulic fluid flow to the steering gear to improve fuel economy, if no additional assist is needed. The calculation of the desired flow control device current is primarily based on vehicle speed and steering wheel rate.

Abstract: A power steering system includes: a first drain passage for draining an oil pressure from a first oil passage, a second drain passage for draining the oil pressure from a second oil passage, and a pair of a first and second switch valves. When one of the first oil passage and the second oil passage is so pressurized by an operation of a reversible oil pump as to have an increased internal pressure, the pair of the first switch valve and the second switch valve allow the following: i) closing one of the first drain passage and the second drain passage which one is connected to the oil passage having the thus increased internal pressure, while ii) opening the other of the first drain passage and the second drain passage which other is connected to the oil passage that is so depressurized as to have a decreased internal pressure.

Abstract: A power steering system includes a rotary slide valve which has a housing, an input shaft and an output shaft which can be rotated relative to each other to a limited extent. A centering piston is provided which is non-rotatably and axially movably connected with the input shaft and delimits a pressure space in the housing. The rotary slide valve further comprises a centering ring which is non-rotatably connected with the output shaft, and arm inlet to the pressure chamber. The pressure chamber has a controlled outlet. There is also proposed a method of operating such a power steering system.

Abstract: An integral power steering apparatus includes a stroke limiter. A piston defines two hydraulic chambers in a housing. A communicating passage, a first valve disposed between the first hydraulic chamber and the communicating passage, and a second valve disposed between the second hydraulic chamber and the communicating passage, are provided to serve for a stroke limiter, in addition to a hydraulic circuit for supplying hydraulic fluid to the two hydraulic chambers. The two valves each include a valve body having a bore and serving as a valve seat, a plunger slidably fitted within the bore of the valve body and serving as a valving element, and a spring disposed on the bottom of the bore of the valve body and biasing the plunger to be in contact with the valve body.

Abstract: A first fluid passage extends from a first outlet/inlet port of a hydraulic pump to a first work chamber of a power cylinder, and a second fluid passage extends from a second outlet/inlet port of the pump to a second work chamber of the power cylinder. A switch system switches the role of the first and second outlet/inlet ports in accordance with a turning direction of a steering wheel. Flow control mechanisms are respectively incorporated with the first and second fluid passages, so that a controlled flow of hydraulic fluid from the hydraulic pump to the first or second work chamber and vice versa are appropriately carried out thereby providing the driver with a comfortable steering feeling. A bypass arrangement may be provided between the first and second fluid passages to deal with a residual pressure that would be remained in the first or second work chamber when the hydraulic pump is under inoperative condition.

Abstract: The invention relates to a rotary slide valve (1) of servo-assisted steering systems for motor vehicles that comprises an input and an output element (3, 4), which can rotate in relation to one another around a limited angle of rotation, and comprises a coupling connection (10) of the output element (4) to a control slide (7). A torque-transmitting, non-distorted coupling connection (10) between the control slide (7) and the output element (4) is provided by a coupling pin (10), which is fixed inside the output element (4) and radially extends into a seat of the control slide (7). The seat axially tapers to a cross-section that matches the cross-section of the coupling pin (10), whereby it is easy to insert the coupling pin (10) into the seat and possible to attain a play-free supporting position for the coupling pin (10) by axially displacing the output element (4) or the coupling pin (10) and control slide (7) in relation to one another.