Abstract: A power steering system is disclosed herein that includes an electronic control unit that determines a set-point value for a damping moment in the power steering system. The system also includes a first sensor connected to the control unit and operable to determine a sign of a steering angle. The sign of the steering angle refers to a clockwise angle from dead center being designated as positive or negative and a counter-clockwise angle from dead center being assigned the other designation. The system also includes a second sensor connected to the control unit and operable to determine the sign of a steering wheel angular velocity. The sign of the steering wheel angular velocity refers to movement of the steering wheel in the clockwise direction being designated as positive or negative and movement in the counter-clockwise direction being assigned the other designation.

Abstract: An adaptive control VGR steering system that varies the steering gear ratio between a vehicle hand-wheel angle and the road wheel angle based on vehicle speed and one or more of hand-wheel angle, driver attentiveness and a driver's driving style and skill.

Abstract: In a pump device applicable to a power steering apparatus, a pump element is housed within a pump housing and is configured to drain a working oil, an electric motor is configured to drive the pump element, a reservoir tank is installed on the housing and is configured to reserve the working oil supplied to the oil element, a passage is formed within the pump housing and is connected to the pump element, and a control valve is installed in the pump housing, is configured to communicate with the passage, and is configured to control a flow of the working oil caused to flow through the passage.

Abstract: The center-pivot vehicle has forward and rearward sections with traversing means for traversing terrain. A rotary actuator connects the forward and rearward sections. Rotation of the rotary actuator articulates the forward and rearward sections relative to each other for steering the vehicle. The present invention also includes a method for controlling articulation of a center-pivot vehicle which includes connecting first and second sections of the center-pivot vehicle together with a rotary actuator, powering the rotary actuator with an engine and providing a steering input by an operator for operating the rotary actuator for rotating the rotary actuator and articulating the first and second sections of the vehicle relative to each other for turning the vehicle.

Abstract: A steering system includes a fluid actuator, a first steering circuit in selective fluid communication with the fluid actuator, and a second steering circuit in selective fluid communication with the fluid actuator and disposed in parallel to the first steering circuit. The second steering circuit includes a load-reaction feature and an isolation valve with the isolation valve being adapted to enable and disable the load-reaction feature.

Abstract: A power steering system comprises a hydraulic circuit, a pump arranged to pressurize hydraulic fluid and valve means arranged to control the flow of pressurized fluid in the hydraulic circuit to control the steering force provided by the system. The system further comprises a motor arranged to drive the pump and control means arranged to control operation of the motor, and the control means is arranged to determine the position of the motor from a plurality of parameters by means of a position determining algorithm.

Abstract: A wheel-side end of a connection link is freely inclined relative to the wheel. A shaft-side end of the connection link is movable substantially in a width direction of the vehicle for steering the wheel. A steering shaft body is substantially in a rod shape extending substantially in the width direction. A steering shaft end is fixed to one end of the steering shaft body and freely inclined relative to the shaft-side end. The steering shaft body and the steering shaft end are movable substantially in the width direction according to an operation of a steering device. A load sensor is interposed between the steering shaft end and the steering shaft body for detecting load applied in an axial direction of the steering shaft to detect force applied to the wheel.

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 clutch device of an oil pump in a power steering system includes a pulley shaft coupled with a pulley connected with a crankshaft of an engine via a belt, a body shaft coupled with a rotor rotatably installed in a pump body and provided with a vein, clutch plates provided in the pulley shaft and the body shaft, and transmitting a rotation power of the pulley shaft to the body shaft or blocking the rotation power therebetween, an elastic member provided in the body shaft, a check valve installed on a supply port connecting an airtight space, a solenoid valve installed on a return port connecting the airtight space in the pump body with an input port through which oil is supplied to the pump body, and a controller to control the operation of the solenoid valve.

Abstract: Provided is a power steering apparatus capable of suppressing an abrupt change in steering force and preventing a deterioration in steering feeling even in the event of a transition from power steering to manual steering. The power steering apparatus includes a torque sensor, a motor of a permanent magnet field type, and a controller having a motor driving unit and an abnormality monitoring unit, for controlling the driving of the motor. The motor driving unit includes an inverter for driving the motor, and a drive signal generating unit for calculating a target current caused to flow through the motor and outputting a drive signal of the inverter based on the target current. The abnormality monitoring unit includes an abnormality processing unit for constituting a closed-loop circuit including the motor in stopping the driving of the motor.

Abstract: A priority valve 7 is disposed between a hydraulic pump 2 and a steering valve 4 and is used to supply priority steering cylinders 103a and 103b with pressurized oil discharged from the hydraulic pump 2 by controlling the differential pressure across a meter-in hydraulic line of the steering valve 4 such that the differential pressure is kept at a target value. A pressure sensor 31 for detecting the load pressures of the steering cylinders 103a and 103b is provided. On the basis of the detected load pressures, the target value set for the priority valve 7 is modified by devices including a controller 32, a solenoid valve 33, a pilot hydraulic line 29, and a pressure receiving unit 24c of the priority valve 7. The above configuration enables suppression of a shock occurring at the start of turning of the steering wheel.

Abstract: A multiple-speed steering system for an off-road vehicle having a loading mechanism and a hydraulic steering system associated with guiding the vehicle. The multiple-speed steering system includes a hydraulic steering cylinder and a first component fluidly coupled to the steering cylinder to provide a primary metered flow of hydraulic fluid to the steering cylinder. A second component is selectively fluidly coupled to the steering cylinder to provide a supplemental metered flow in addition to the primary metered flow of hydraulic fluid to the steering cylinder. Addition of the supplemental metered flow is selectable by an operator of the vehicle.

Abstract: An alignment changing control device that includes: a motor drive section which adjusts electrical power supplied to a motor of the electric actuator according to an operation command and, when receiving an operation inhibiting signal, limits or stops supplying the electrical power to the motor; a motor temperature estimating section for calculating an estimated temperature of the motor from at least a current supplied to the motor, an outside air temperature and a vehicle speed, based on heat balance relationship; and a comparator which transmits the operation inhibiting signal to the motor drive section when the estimated temperature of the motor calculated by the motor temperature estimating section is higher than a predetermined temperature, which is equal to or lower than an operation allowable temperature of the motor.

Abstract: The present invention provides a power assist steering system for use with a motor vehicle utilizing a torque sensor and an electronically controlled hydraulic valve used to supply or meter hydraulic fluid to a hydraulic cylinder that provides power assist to the steering system. The torque sensor measures driver input and provides a signal to the controller that controls an electrically actuated hydraulic valve. Additionally, steering wheel rotational speed and position are also input to the controller wherein the controller generates a steering assist command that minimizes the magnitude of difference, or error, between the steering torque reference value determined from the steering wheel speed and position and the measured torque. By doing so, the invention controls steering wheel feel, as opposed to the conventional practice of controlling the steering assist boost curve.

Abstract: A torque steer reduction system is disclosed. The system includes a damper. The damping effect of the damper is variable. Furthermore, the damping effect may be adjusted through a damping coefficient. High damping coefficients may correspond to stronger damping effects. During periods associated with a greater influence of torque steer, the damper may be configured with a high damping coefficient to counteract torque steer.

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: A power assist steering system for a vehicle, especially for a truck or commercial vehicle, is disclosed that includes a mechanical engine-driven power steering pump that pumps hydraulic fluid to a power steering unit, and an electrical pump adapted to pump hydraulic fluid so as to optimize a power steering flow to the power steering unit and to minimize internal pump flow.

Abstract: A method of steering a vehicle with a hydraulic steering system is disclosed. A first control signal is sent to a pilot valve. The pilot valve is operated to direct pilot fluid to a main valve in response to the first control signal. The main valve is opened to a first position in response to the pilot fluid. Fluid is directed through the main valve to a first actuator. Resistance to actuation of the first actuator is detected. The detected resistance is compared to a threshold resistance. A second control signal is sent to the pilot valve when the detected resistance exceeds the threshold resistance. The pilot valve is operated to direct pilot fluid to the main valve in response to the second control signal. The main valve is opened to a second position in response to the pilot fluid. Fluid is directed through the main valve to the first actuator and a second actuator.

Abstract: In a steering operation device, a hydraulic actuator is driven by hydraulic pressure and vary the steering angle of the vehicle. A steering valve adjusts the flow rate of oil supplied to the actuator according to a pilot pressure. A pilot valve adjusts the pilot pressure input to the steering valve according to a difference between a displacement of an operation input shaft and a displacement of a feedback input shaft. A joystick lever is linked to the operation input shaft and moves the operation input shaft according to a tilt angle. A drive device displaces the feedback input shaft. A steering angle sensor detects the steering angle and outputs the angle as a detected signal. A controller sends a command signal to the drive device so as to displace the feedback input shaft according to the detected steering angle.

Abstract: The present invention provides a power assist steering system for use with a motor vehicle utilizing a torque sensor and an electronically controlled hydraulic valve used to supply or meter hydraulic fluid to a hydraulic cylinder that provides power assist to the steering system. The torque sensor measures driver input and provides a signal to the controller that controls an electrically actuated hydraulic valve. Additionally, steering wheel rotational speed and position are also input to the controller wherein the controller generates a steering assist command that minimizes the magnitude of difference, or error, between the steering torque reference value determined from the steering wheel speed and position and the measured torque. By doing so, the invention controls steering wheel feel, as opposed to the conventional practice of controlling the steering assist boost curve.

Abstract: A method, system, and computer program product for calculating a torque overlay command in a steering control system is provided. The method includes receiving a current hand wheel angle, receiving a change in vehicle yaw moment command, and calculating a lateral force in response to the change in vehicle yaw moment command. The method also includes determining a new tire side slip angle from the lateral force and calculating a commanded hand wheel angle from the new tire side slip angle. The method further includes calculating an error signal as a difference between the commanded hand wheel angle and the current hand wheel angle, and generating a torque overlay command from the error signal.

Abstract: A hybrid electrical power assist system (EPAS) for an automotive vehicle that utilizes the advantages of a conventional EPAS system to provide power assist based upon several distinct sensor inputs, in a heavy duty vehicle that requires significantly more assistance forces than a conventional EPAS can provide. The hybrid system utilizes a hydraulic amplifier that is connected to receive the torque output from an EPAS motor actuator and responsively provide a fluid under differential pressure through a pair of high pressure lines to a steering piston.

Abstract: A method of determining a direction of a power boost applied to a power cylinder of a variable effort power steering system includes measuring a pressure of a hydraulic fluid between a pump and a control valve. A first position of the hand wheel is detected and initialized when the pressure is within a pre-defined equilibrium pressure range. A second position of the hand wheel is detected in response to rotational movement of the hand wheel. The first position and the second position of the hand wheel are measured in cumulative degrees rotated left or right of a on-center orientation of the hand wheel. The second position is subtracted from the first position to obtain a differential value representing the direction of the power boost. A negative differential value represents a first direction and a positive differential value represents a second direction of the power boost.

Abstract: A hydraulic steering unit 5 generates a control pressure corresponding to the rotational quantity and rotational direction of the steering wheel 109 on the basis of pressurized oil of a pilot pump 13. Signals of pressure sensors 6a and 6b used to detect the control pressure, and a signal of a front operation detection unit 31, are inputted into a controller 132. A controller 32 and solenoid valves 33a and 33b control a stroke of a steering valve 4 so that the stroke becomes larger with increase in control pressure detected by each of the pressure sensors 6a and 6b. In addition when the operation of a front work device is detected, the controller 32 and the solenoid valves 33a and 33b control the stroke of the steering valve 4 so that the stroke becomes larger than that provided when the operation of the front work device is not detected.

Abstract: An electrically driven power steering system for a vehicle comprises a steering sensor for detecting a steering operation of a steering wheel and a power steering control unit, which receives a command signal from a vehicle movement total control unit, calculates a target steering assist torque from a steering signal from the steering sensor and the command signal and drives a steering assist electric motor in accordance with the above calculated target steering assist torque. The power steering control unit further calculates a feasible torque to be generated at the steering assist electric motor, and drives the steering assist electric motor at the feasible torque, when the feasible torque is lower than the target steering assist torque, namely when a driving current to the electric motor should be limited due to an increased temperature of the electric motor and so on.

Abstract: The invention concerns a hydraulic steering with a steering motor arrangement having at least one steering motor, and with at least two steering circuits, each having a steering valve that interrupts a path from a pressure supply to the steering motor arrangement in the neutral position and releases a path from the pressure supply to the steering motor arrangement on a movement out of the neutral position. It is endeavored to simplify the embodiment of such a steering. For this purpose, the steering valve (5a, 5b) has two end positions, one on each side of the neutral position, in which positions a path from the pressure supply (15, 21) to the steering motor arrangement (2) is interrupted.

Abstract: A method, system, and computer program product for tire slip angle limiting in a steering control system for a vehicle are provided. The method includes calculating a first steering augmentation angle from a vehicle speed and a handwheel angle. The method further includes calculating an upper bound angle limit and a lower bound angle limit as functions of a vehicle slip angle and a tire slip angle limit. The method also includes bounding the sum of the handwheel angle plus the first steering augmentation angle between the upper bound angle limit and the lower bound angle limit to produce a first bounded angle. The method additionally includes subtracting the sum of the handwheel angle plus the first steering augmentation angle from the first bounded angle to produce a first limiting function, and producing a motor angle command by adding the first limiting function plus the first steering augmentation angle.

Abstract: A hydraulic power steering system that maintains proportional pressure control between an input side of a gear and assist pressures internal to the steering gear by relying upon a control valve. A pressure differential is maintained between the input side of a gear and assist pressures internal to the steering gear throughout certain events. Those events include running the pump to fully charge the accumulator, idling the pump after fully charging the accumulator, discharging pressure from the fully charged accumulator at an onset of a steering event having a demand for steering load, recovering the discharged pressure of the accumulator by running the pump after turning on the pump at the onset of the steering event, and opening the relief valve in the valve manifold during the steering event.

Abstract: A variable rack stroke system includes a rack housing in which a rack bar is slidably disposed, a casing attached to the rack housing, an annular rotary member, an annular stationary member, and a switch. The annular rotary member includes grooves on an inner periphery thereof that face each other, and first protrusions protruding from the rotary member in an axial direction that have different thicknesses. The rotational phase of the rotary member is adjusted by the motor. The annular stationary member includes protruding parts on an outer periphery thereof that face each other, configured to be inserted into the grooves, and second protrusions protruding from the stationary member in the axial direction, that have different thicknesses and face the first protrusions. The stationary member is coupled with a ball joint to be coupled with the rack bar. The switch adjusts the rotational phase of the motor.

Abstract: A vehicle motion state control device controls an actuator capable of regulating a vehicle motion state so that an actual yaw rate approaches a target yaw rate determined based on a steer angle and a vehicle speed, target yaw rate limit values for left and right turn directions of a vehicle are individually determined by a target yaw rate limit value determining mechanism based on detected lateral acceleration, detected vehicle speed, and predetermined set minimum lateral acceleration set in a direction opposite to that of the detected lateral acceleration; and target yaw rates for the left and right turn directions are determined by a target yaw rate determining mechanism while limiting them by the determined target yaw rate limit values. Thus, an oversteer control is started at an early timing when an abrupt steering operation at a large steer angle occurs which causes a phase difference to the yaw rate and the lateral acceleration.

Abstract: A steering system is provided for a work vehicle comprising articulated first and second vehicle sections. The steering system comprises a controller adapted to: determine from a speed-request signal if a requested steering speed requested for the first vehicle section relative to the second vehicle section about an articulation axis toward an end of an end region of a position range of the first vehicle section is at least a predetermined steering speed; determine from a position signal if the first vehicle section is positioned in the end region of the position range; and, if the requested steering speed is at least the predetermined steering speed and the first vehicle section is positioned in the end region, signal that an actual steering speed of the first vehicle section be lower than the requested steering speed. An associated method is disclosed.

Abstract: The present invention offers a power steering device for a four-wheel drive, which includes: a first self-aligning torque estimation unit for estimating a self-aligning torque generated in a current vehicle behavior as a first self-aligning torque; a second self-aligning torque estimation unit for estimating a self-aligning torque that is to influence a subsequent vehicle behavior as a second self-aligning torque; a self-aligning torque change amount calculation unit for calculating a difference of the second self-aligning torque from the first self-aligning torque as a self-aligning torque change amount; and an assisting force correction unit for determining and outputting a corrected value of an assisting force to be generated for a steering operation based on the self-aligning torque change amount.

Abstract: A device for controlling torsional stiffness of a power steering system, may include a variable torsion bar, an input shaft that is connected with a steering wheel, a pinion shaft equipped with a pinion gear engaged with a rack bar of a steering gear box, wherein the input shaft and the pinion shaft are combined each other to form a guide hole and slidably receive the variable torsion bar therein, and an actuating apparatus that moves the variable torsion bar toward the input shaft or the pinion shaft along a longitudinal axis of the input shaft and the pinion shaft according to a hydraulic pressure so as to change a size of a cross-section of the device.

Abstract: The invention concerns a hydraulic steering with a steering initiator, a steering unit with feedback properties, which can be activated by the steering initiator, the steering unit having a supply connection arrangement with a pressure connection (P) and a tank connection (T) and a working connection arrangement with two working connections (L, R), an auxiliary-force operated steering valve, which is located in parallel with the steering unit between the supply connection arrangement (P, T) and the working connection arrangement (L, R), and a feedback suppressing device, which is active, when the steering valve is active. It is endeavoured to find a simple manner of ensuring the priority of the steering initiator over the steering valve. For this purpose, the steering initiator interacts with an activation sensor, which deactivates the feedback suppressing device on an activation of the steering initiator.

Abstract: The invention concerns a hydraulic steering with a steering initiator, a steering unit with feedback properties, which can be activated by the steering initiator, the steering unit having a supply connection arrangement with a pressure connection (P) and a tank connection (T) and a working connection arrangement with two working connections (L, R), an auxiliary-force operated steering valve, which is located in parallel with the steering unit between the supply connection arrangement (P, T) and the working connection arrangement (L, R), and a feedback suppressing device, which is active, when the steering valve is active. It is endeavoured to find a simple manner of ensuring the priority of the steering initiator over the steering valve. For this purpose, the steering initiator interacts with an activation sensor, which deactivates the feedback suppressing device on an activation of the steering initiator.

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: In a hydraulic power steering apparatus, hydraulic pressure for generating steering assist power is varied by varying opening of a variable throttle portion by movement of a spool. The spool is disposed in a provisional origin by driving a stepping motor in one direction according to a number of steps for setting provisional origin from a position at a time of start of control, and the number of steps at a time of completing of the driving is set to a provisional origin for calculation. In a return to origin permission state where the spool is disposed in a provisional origin and the number of steps from the provisional origin for calculation is zero, a number of steps at a time when the driving of the stepping motor according to a number of steps obtained by subtracting the number of steps for setting provisional origin from a number of steps for setting origin is completed is set to an origin for calculation, and the movement of the spool is stopped at the origin with a stopper.

Abstract: A steering system for a machine having at least one steerable traction device is disclosed. The steering system may have a steering actuator operatively connected to the at least one steerable traction device, and a travel speed sensor configured to generate a signal indicative of a travel speed of the machine. The steering mechanism may also have an operator input device having a deadzone. The deadzone may vary in response to the signal. The steering system may also have a controller in communication with the steering actuator, the operator input device, and the travel speed sensor. The controller may be configured to affect operation of the steering actuator in response to operation of the operator input device only when the operation of the operator input device deviates from the deadzone.

Abstract: An electric power steering device that can estimate an ambient temperature and apply current limiting without using ambient temperature detecting means is provided. The electric power steering device includes a motor that supplements the driver's steering force, a controller that determines and controls the quantity of current passed to the motor, and vehicle speed detecting means. The electric power steering device includes ambient temperature estimating means provided with a vehicle speed signal input from the vehicle speed detecting means and limits the quantity of current passed to the motor according to an output from the ambient temperature estimating means.

Abstract: System for controlling at least one hydraulic cylinder (2, 3) having a first control valve unit (4) connected to the hydraulic cylinder for regulation thereof. A first operable control means (5) is included and which is adapted for controlling the first control valve unit. A second control valve unit (6) is also included that is connected to the hydraulic cylinder for regulation thereof, and a second operable control means (7) is further provided and which is adapted for controlling the second control valve unit. The system also includes means (23) for prioritizing the first control means. The prioritizing means (23) is controlled via hydraulics in such a way that the effect of the second control means (6) on the regulation of the hydraulic cylinder (2, 3) is at least substantially reduced as soon as the first control means (5) is operated.

Abstract: In a power steering device employing a hydraulic power cylinder, a motor-driven pump, and a driving power source for the motor, a power steering control system is configured to electrically connected to at least the motor and the power source for controlling a driving state of the motor and a power source voltage of the power source. The power steering control system includes a motor control circuit that generates a motor driving signal, whose command signal value is determined based on a steering assist force applied through the power cylinder to steered road wheels, a booster circuit that boosts the power source voltage, a motor angular acceleration detection circuit that detects or estimates a motor angular acceleration, and a booster-circuit control circuit that controls, responsively to the motor angular acceleration, switching between operating and non-operating states of the booster circuit.

Abstract: There is provided a power steering system including an electric motor for generating a steering force in response to an command value, and a controller for generating the command value to the electric motor. Here, the controller generates the command value in correspondence with steering state of wheels, thereby controlling torque or rotation number of the electric motor.

Abstract: The method consists in: determining in which actually sector the booster motor is located, a sector of the booster motor being defied by two successive poles; determining a relative angle position of the steering wheel in relation to the booster motor; identifying a sector, known as neutral, in which the booster motor is located when the rotation speeds of the rear wheels, i.e. right and left of the vehicle, are equal; determining an angle offset of the steering wheel corresponding to a neutral angle position of the steering wheel; determining an absolute angle position of the steering wheel which is equal to the difference between the relative angle position of the steering wheel and the offset angle thereof.

Abstract: The invention describes vehicles where the steering effect of the driver-selected wheel angles is made identical to the steering effect of positively and independently driving the driven wheels. Means of delivering most of the power to each of the driven wheels by means of shaft drives is also described. Here speed-correcting differentials are close coupled to each driven wheel where the first input to the said differentials is by means of shaft drives, and the second input to the said differentials is provided by means of speed-correcting hydraulic or electric motors.

Abstract: A hydraulic power steering system that maintains proportional pressure control between an input side of a gear and assist pressures internal to the steering gear by relying upon a control valve. A pressure differential is maintained between the input side of a gear and assist pressures internal to the steering gear throughout certain events. Those events include running the pump to fully charge the accumulator, idling the pump after fully charging the accumulator, discharging pressure from the fully charged accumulator at an onset of a steering event having a demand for steering load, recovering the discharged pressure of the accumulator by running the pump after turning on the pump at the onset of the steering event, and opening the relief valve in the valve manifold during the steering event.

Abstract: A power steering system for translating movement to a pair of wheels of a vehicle having an engine is disclosed. The system includes a steering assembly adapted for coupling engagement to the wheels for turning the wheels. The system includes a hydraulic pump having a pump input and a pump output and is coupled to the steering assembly and a planetary gear set. The system also includes a steering shaft operatively connected to the hydraulic pump for controlling a direction of the pump output and coupled to the steering assembly. The system further includes a variable-ratio drive mechanism having an electric motor and a controller. The electric motor is coupled to the planetary gear set and the controller communicates with the electric motor for controlling a rotational speed of the planetary gear set to maintain the pump output.

Abstract: A rear axle steering system for a mobile crane including at least one actively steered rear axle with wheels arranged thereon. A rear axle steering system of this type is provided with a hydraulic steering system including one or more hydraulic steering cylinders of which a particular number are in each case associated with an actively steered rear axle in order to steer this actively steered rear axle in a desired manner. A braking system is adapted to individually brake each wheel of the at least one actively steered rear axle. In the event of an error in the hydraulic steering system, a control system actuates the braking system in such a way that by selective braking of at least one wheel of the actively steered rear axle, which is affected by this error, the rear axle is brought to a predetermined, desired steering position. A method of steering a rear axle, with wheels of a mobile crane arranged thereon, by means of a hydraulic steering system.

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 steering system, comprising: an input cylinder having a first hydraulic chamber and a second hydraulic chamber; a transmission mechanism, wherein a transmission efficiency for converting and transmitting a linear motion of the input cylinder to a rotary motion of a steering wheel is less than a transmission efficiency for converting and transmitting the rotary motion of the steering wheel to the linear motion of the input cylinder; an output cylinder connected to a steerable vehicle wheel and having a third hydraulic chamber and a fourth hydraulic chamber; a first hydraulic passage for connecting the first hydraulic chamber to the third hydraulic chamber; a second hydraulic passage for connecting the second hydraulic chamber to the fourth hydraulic chamber; a flow rate control mechanism for exchanging hydraulic oil with: a first hydraulic circuit including the first and third hydraulic chambers and the first hydraulic passage; and a second hydraulic circuit including the second and fourth hydraulic chambers

Abstract: An electrically actuated, hydraulic power steering system is provided. The steering system includes a hydraulic pump for generating hydraulic pressure, a hydraulic fluid reservoir, a hydraulic cylinder, and a control valve arrangement that selectively connects the hydraulic cylinder to the pump and the hydraulic fluid reservoir. The control valve arrangement is characterized during the on-center position by a first and a second chamber of the hydraulic cylinder being in fluid communication with each other but not with the fluid reservoir. In one embodiment, the steering system has a steering sensor, a control box, and two pressure accumulators for providing at least two levels of steering assist.