Abstract: A flow controlling apparatus to control flow rate of working fluid discharged from pump apparatus to a power steering apparatus including a electric variable throttle, a solenoid mechanism and a spool. The solenoid mechanism varies opening degree of the electric variable throttle based on a electric signal from electric controller. The spool slides in accordance with the differential pressure of the variable throttle due to increase of flow rate of working fluid discharged from pump apparatus so as to return excess working fluid to bypass passage connecting to a suction port of pump apparatus. The flow controlling apparatus further comprising means for increase flow rate of bypass flow to bypass passage when rotating speed of the pump apparatus exceed predetermined value.

Abstract: A power steering system and a method of charging the power steering system with hydraulic fluid are provided. Hydraulic fluid is selectively supplied to hydraulic chambers of a power cylinder via oil passages from a reversible pump, according to a steering torque. In addition, a bypass passage is provided between oil passages. A normally open switching valve is provided in the bypass passage. When the system is assembled, the hydraulic fluid is supplied from an oil reservoir via the switching valve or the reversible pump, and circulated in the hydraulic circuit. The air in the hydraulic circuit is discharged via the switching valve.

Abstract: An apparatus (10) for helping to turn steerable wheels (12) of a vehicle comprises a hydraulic power-assisted steering gear (16). An electric motor (92) actuates the steering gear (16). A pump (84) supplies the steering gear (16) with hydraulic fluid. A vehicle speed sensor (102) senses vehicle speed and provides a vehicle speed signal. A controller (104) is responsive to the vehicle speed signal for controlling the pump (84). The controller (104) activates the pump (84) to supply hydraulic fluid to the steering gear (16) when the vehicle speed signal indicates a vehicle speed below a predetermined value and the controller (104) deactivating the pump (84) when the vehicle speed signal indicates a vehicle speed above the predetermined value.

Abstract: The present invention involves a system and method of controlling a variable steering ratio of a vehicle steer-by-wire system. The variable steering ratio control varies the steering ratio continuously according to steering angle and vehicle speed. The method comprises sensing an actual steering wheel angle and an actual speed of the vehicle and converting the actual steering wheel angle and vehicle speed into values in fuzzy sets based on a steering wheel angle and vehicle speed membership functions with linguistic term labels. The method further includes determining a corresponding degree of membership of the steering wheel angle and vehicle speed. The method further includes inferring a fuzzy road wheel reference angle output value by determining the degree of membership function for the road wheel reference angle using fuzzy rules based on the degrees of steering angle and the vehicle speed. The method further includes converting a fuzzy road wheel angle into an actual road wheel angle.

Abstract: The invention provides a compact and highly reliable motor vehicle steering device that does not require a spiral flat cable. The motor vehicle steering device includes variable gear ratio system that modifies the transmission ratio of the rotary motions between first steering shaft and second steering shaft. Variable gear ratio system comprises Strain Wave Gearing Speed Reducer that modifies the transmission ratio between first steering shaft and second steering shaft in response to the rotating speed of motor shaft. Motor shaft and second steering shaft forms a substantially concentric dual structure, drive motor is affixed, and output shaft is connected to motor shaft.

Abstract: A steering apparatus controller for an electric power steering apparatus, which includes an electric motor for generating assist torque for assisting steering of a steering wheel and the steering apparatus controller is designed to execute a feedback control of the applied drive voltage to the electric motor based on the detection result of the actual current that flows through the motor. A sensor detects the actual current to produce the detection result. When detecting an abnormal decrease of the drive voltage of the sensor, a voltage controller maintains the applied voltage to the electric motor at the voltage at a predetermined time before the drive voltage abnormally decreased.

Abstract: In an embodiment of the present invention, an apparatus for steering a vehicle is disclosed. The apparatus includes a back-drivable steer-by-wire system including a road wheel actuator assembly coupled to a wheel of the vehicle. The road wheel actuator assembly defines a steering axis and the steering axis is off-set from a longitudinal axis of the wheel by a positive scrub radius. In an embodiment for a method in accordance with the present invention, a method to steer a vehicle after failure of a road wheel actuator assembly in a back-drivable steer-by-wire steering system is disclosed. The method includes the acts of applying a braking force to the wheel and generating a torque on the road wheel actuator assembly by the applied braking force acting through a positive scrub radius.

Abstract: A vehicle steering control system is provided which is capable of reliably protecting a motor for driving a wheel steering shaft. The offset output characteristic of a current sensor for detecting the electric current applied to the steering shaft drive motor is actually measured prior to the actual use of the steering control system, and offset compensation information is prepared based on the measured value of the offset output characteristic for storage in an EEPROM. Further, an output value of the current sensor and an output value of a reference current measuring system are measured independently of each other with the supply voltage for use in measurement being set to a constant value. Then, current gain compensation information is prepared based on the output values so measured and is stored in the EEPROM. In the later actual use (i.e.

Abstract: An electric power steering control device is provided, which comprises a vehicle speed detector, a steering torque detector, a steering shaft reaction torque meter, a motor speed detector, a motor acceleration detector, a steering torque detector for calculating a base target current, a damping compensator for finding a gain of a damping torque based on a steering shaft reaction torque to calculate a damping compensation amount based on the damping torque gain and motor speed, an inertia compensator for finding a gain of an inertia compensation torque based on the steering shaft reaction torque to calculate an inertia compensation amount based on the inertia compensation torque gain and motor acceleration, and an adder for compensating a base target current by a damping compensation amount and an inertia compensation amount to calculate a target current.

Abstract: A new and novel device for controlling a steering characteristic of a vehicle such as automobile so as to enhance an effect of suppressing a change in a behavior of the vehicle body due to a difference between driving and braking forces on the left and right wheels is characterized in that the device makes an amount of controlling the steering characteristic smaller as an index indicating an amount of a shift of vertical loads between the left and right wheels is increased. The steering characteristic is modified through controlling steering assist torque or a steering angle of the steered wheels. The steering assist by the steering control device is fully effective when the vehicle is running on a straight road having surfaces of different frictional coefficients while less effective on a curved road having a uniform frictional surface, preventing undesirable and unexpected modification of the steering characteristic during turning of the vehicle.

Abstract: A vehicle speed response type power steering system, wherein, when a vehicle is moving at a relatively slow speed, a relatively large auxiliary power is generated to enable a driver to easily adjust a steering of the vehicle with relatively little steering power, and when a vehicle is moving at a high speed, a relatively small auxiliary power is generated to prevent an abrupt turn in order to stabilize the steering operation of the vehicle, such that formation of appropriate auxiliary power in response to a vehicle speed allows a driver to carry out an easy and safe steering manipulation.

Abstract: An energy saving system and method reduces power consumption of an electro-hydraulic power steering system of a hybrid vehicle. The electro-hydraulic power steering system includes a first controller that communicates with an electric motor that is coupled to a hydraulic pump. The first controller selects Standby, On or Off operating modes for the electro-hydraulic power steering system. The first controller applies power to the electric motor and the first controller based on the selected operating mode to reduce power consumption. The first controller turns the first controller off and the motor off when in the Off operating mode. The first controller turns the electric motor off and the controller on when in the Standby operating mode. The first controller turns the electric motor on and the controller on when in the On operating mode.

Abstract: A dynamically adjustable motion stabilizer, including a motion stabilizer in combination with a centering adjustment mechanism for yieldingly urging a relatively movable load member toward a normal or centered position relative to another load member, includes a telescoping body that shortens (retracts) as the load members move toward one another and lengthens (extends) as the load members move apart. The centering adjustment mechanism includes a spring assembly, a locking mechanism structured to lock the spring assembly, a releasing mechanism structured to unlock the locking mechanism, and a control mechanism structured to control the releasing mechanism.

Abstract: A system for reducing steering nibble and other vibrations in a power-assisted steering system increases the amount of damping force when a power steering boost system is applying little or no steering force to the steering actuator, and reduces the amount of damping force when the power boost system is applying significant steering force to the steering actuator. A damping member is formed of a polymer material and is urged into contact with the steering actuator by a spring-biased clamping member. A shuttle valve regulates pressure from the hydraulic steering boost system to overcome the spring biasing force whenever hydraulic pressure is applied to the steering actuator. The preload of the spring biasing mechanism is varied by an electronic control unit that receives inputs from a driver-activated switch, and from vehicle condition sensors to allow automatic, adaptive adjustment of the damping to optimize driving comfort and safety.

Abstract: A steer-by-wire system of the preferred embodiment of the invention includes a steering sensor, a turning subsystem, a vehicle sensor, and a controller subsystem. The turning subsystem further includes a first turning actuator to adjust a turning angle of a first road wheel, a first turning sensor to sense first turning factors of the first turning actuator, a second turning actuator to adjust a turning angle of a second road wheel, and a second turning sensor to sense second turning factors of the second turning actuator. The controller subsystem is connected to the steering sensor, to the first turning sensor, to the second turning sensor, and to the vehicle sensor. The control subsystem independently controls the first turning actuator and the second turning actuator.

Abstract: In a control unit for use with a power steering apparatus, there are provided and integrated into a single body, a main operating fluid feed device for supplying the hydraulic cylinder with an amount of oil corresponding to the amount of rotation of the steering wheel H, an auxiliary operating fluid feed device for supplying a correcting oil for adjusting drive of said hydraulic cylinder according to control signal, and a steering wheel angle sensor disposed around the rotating shaft of the steering wheel connected to said main operating fluid feed device, to detect steering wheel angle corresponding to the rotating position of said steering wheel.

Abstract: The invention concerns a method of steering a vehicle, particularly an articulated vehicle, in which a valve element of a main valve is moved so that it releases or closes connections between a supply connection arrangement and a working connection arrangement in dependence of a steering direction and a steering angle. To improve the steering comfort, the movement speed of the valve element is controlled.

Abstract: An improved system for achieving optimum steering angles for wheels incorporates a sensor which senses the steering angle of a first wheel. The optimum angle is sent to a control which then determines the optimum angle for the other steered wheel based upon known formulas. The optimum angle is determined, and an adjustment structure associated with the tie rod then drives the second wheel to achieve the optimum steered angle.

Abstract: The entire right, title and interest in and to this application and all subject matter disclosed and/or claimed therein, including any and all divisions, continuations, reissues, etc., thereof are, effective as of the date of execution of this application, assigned, transferred, sold and set over by the applicant(s) named herein to Deere & Company, a Delaware corporation having offices at Moline, Ill. 61265, U.S.A., together with all rights to file, and to claim priorities in connection with, corresponding patent applications in any and all foreign countries in/the name of Deere & Company or otherwise.

Abstract: A steering system comprises a hand wheel positioned for manipulation by a driver, a steering shaft extending from the hand wheel, and a magnetic column lock. The steering shaft is supported by a steering column housing so that it can rotate on its own axis. The magnetic column lock includes a rotor attached to steering shaft, a stator attached to column housing, and magnetorheological fluid filling a space between the rotor and stator. In another aspect of the steering system, the steering shaft extends from the hand wheel through a hand wheel actuator having a position sensor and a motor for providing driver feedback. A steering column extends from a lower portion of said steering shaft to a rack, and includes a pinion at its lower end for engagement with the rack, so that the rack translates left and right when the pinion is rotated in corresponding directions. The rack is connected to the front road wheels and causes the front road wheels to steer when it is translated.

Abstract: A power steering apparatus is provided to generate an assistant force corresponding to a change of viscous friction in the steering unit or the like, without losing information on reaction force from a road surface. An external force calculation portion calculates an external force, that is, a force other than a force for steering (i.e. a steering force) among forces (action forces) acting on the steering unit of a vehicle. The external force is assumed to be composed of an outside force received from the road surface, such as an SAT (self-aligning torque), and an internal drag resulting from a viscous friction generated in the steering unit, and the like and these two forces are separated in an outside force and internal drag calculation portion. In separating these two forces, under the assumption that the outside force is a function of a side slip angle and an internal drag is a function of a steering angular velocity, and coefficients of functions are obtained.

Abstract: The invention concerns a servo-assisted steering system (1) for a motor vehicle, in which the steering system (1) comprises a steering wheel (2) for presetting a desired steering angle for the wheels (3) of the motor vehicle, driving-dynamics means (4) for superimposing a correction angle on the steering angle, said correction angle being determined with a view toward increasing the driving stability and/or the driving comfort of the motor vehicle, and a servo drive (6). To keep the efficiency of the driving-dynamics means (4) nearly constant over the entire road-speed range of the vehicle, it is proposed that the servo drive (6) be implemented as a variable torque assistance system, the degree of torque assistance (M) being dependent on the road speed (V) of the vehicle and on at least one variable of the driving-dynamics means (4) that characterizes the correction angle.

Abstract: A steering actuator is prevented from generating excess steering torque that gives an uncomfortable feeling to a driver who is holding a steering wheel when a collision between a vehicle and an oncoming vehicle is avoided by automatic steering by the actuator. When there is a possibility of a collision between the vehicle and an oncoming vehicle, the collision with the oncoming vehicle is avoided by supplying a lateral movement control current having a sinusoidal shape to the actuator of an electric power steering device to move the vehicle laterally. The yaw angle of the vehicle is detected by integrating the yaw rate simultaneously with the start of the lateral movement, and in order to return the vehicle attitude of the vehicle to its original state by converging the yaw angle to 0 in the final stage of the lateral movement, a yaw angle correction control current is superimposed on the lateral movement control current and supplied to the actuator.

Abstract: Unless the steering operation quantity detected by a steering quantity detection unit indicates that the vehicle is advancing almost rectilinearly, an approach disallowed area present toward the outer side of the turning vehicle relative to the front of the vehicle along the advancing direction, such as a road boundary, a blocking wall or a white line, is detected by an approach disallowed area detection unit. A mode judging unit judges that a steering angle limit mode is set if an approach disallowed area has been detected. An &agr; calculating unit calculates an angle &agr; formed by the orientation of the approach disallowed area boundary and the orientation of the vehicle.

Abstract: A linkage assembly (10) of remotely adjustable length extends between a steerable member (17) and a frame member (12) to define the center position of the steerable member (17). The linkage assembly includes a resistance assembly (30) for providing a resistance force resisting forces tending to move the steerable member (17) to either side of the center position, and a trim assembly (28) having a piston (36) that may be locked in position (C1) in a trim cylinder (33) for transmitting steering forces to the resistance assembly (30). A trim valve (52, 52′, 52,″ 301) is operable between a closed position for preventing trim fluid flow so that the piston (36) is held in its locked position (C1), and an open position for allowing the trim piston (36) to move away from its prior locked position (C1) to a new locked position (C2) to permit the length of the linkage (10) to be changed in response to a steering force applied to the steering wheel.

Abstract: A hydraulic power steering apparatus 1 which is arranged so that a damper valve 10 is disposed in hydraulic oil circuits 8 and 9 for connecting an oil passage selector valve 11 in a gear box with right and left oil chambers of a power cylinder 6. The damper valve 10 comprises a spool valve. And a control oil chamber 21 of the spool valve 10 is connected with a hydraulic oil feed passage 18 for connecting a hydraulic pump 13 which is driven by an internal combustion engine so as to discharge hydraulic oil, with the oil passage selector valve 11. Its back pressure chamber 17 is connected with a hydraulic oil circulating passage 19 for connecting the oil passage selector valve 11 with a reservoir tank 12. Orifices 27 and 28 are provided in connecting oil passages 22 and 20, such that when discharge oil pressure of the hydraulic pump 13 rises, opening of the spool valve 10 increase.

Abstract: For an energy-saving type control, a value of a control low rate QP controlled by a flow control valve V is closer to a value of a flow rate required by an output side such as a power cylinder 8, a steering valve 9 or the like, to suppress a driving torque of a pump P. An excitation current I of a solenoid SOL is specified on the basis of a solenoid current instruction value IT based on a steering torque and a solenoid current instruction value IS defining a standby flow rate.

Abstract: Steering gearbox mechanism for automotive vehicles that allows feeding said hydraulic fluid control mechanism of said steering mechanism with pressurized hydraulic fluid, depending on vehicle's working conditions. Thus, when the vehicle is stopped or running at a very low speed, the hydraulic fluid is sent to the steering mechanism for assistance. At this condition, the user may carry out the driving maneuvers effortlessly. Moreover, when the vehicle is running at high speed the assistance is disconnected, by means of deviating the pressurized fluid back to the fluid reservoir, allowing the engine to continue impelling the pump but without assisting the steering mechanism since at those speeds the user can carry out any maneuver without any effort.

Abstract: Valves are associated and integrated inside a body C. A steering valve includes two cylinders A and B, concentric with the steering shaft D. The cylinder A rolls conjointly with the shaft. The valve controls the direction of the fluid circulation in the cylinders which effect the steering. The safety valve includes two pistons P1, P2 and a spring S, and makes the control easier of the steering, in an occasional lack of fluid pressure (pump damage, fluid leak, cut of the shaft strap, engine stop). A progression valve includes a cylinder and the piston PV. It operates by means of the vacuum effect TV, produced in the engine air admission of the vehicle, controlling the return of the piston P1 in a progressive way, from a certain speed of the said vehicle.

Abstract: The object of the present invention is to offer a steering valve device which can reduce both space of the valve assembly in the vehicle and increment of cost and time for manufacturing the device. The steering valve device has a main valve and a correction valve in a housing. The main valve has a supply port, a drain port, and a pair of a right and a left outlets. The main valve is constructed such that either of the right and the left outlets allows to flow the hydraulic fluid, and the other allows to receive the hydraulic fluid according to an operation of a steering wheel. The correction valve has a communicating passage to communicate the right and the left outlets, and a ball to open and close the communicating passage.

Abstract: A steering system (1) for a vehicle with a first steering arrangement (6), with a first sensor (7), with a second steering arrangement (8), which includes an articulated steering, which has a second sensor (9), and with a steering unit (5). To improve the steering comfort, the steering unit (5) is fixedly connected with the first steering arrangement (6) and the second steering arrangement (8) is connected with a follow-up arrangement, which comprises the first sensor (7), a control device (10) and a valve arrangement (11).

Abstract: A fuzzy steering controller for wheel-type agricultural vehicles with an electrohydraulic steering system is disclosed. The fuzzy controller was developed based on a common-sense model of agricultural vehicle steering. The controller implements steering corrections based upon the desired steering rate and the error between the desired and the actual wheel angles. The controller consists of a variable fuzzifier, an inference engine with a steering control rulebase, and a control signal defuzzifier. The controller could be used on different platforms. Tuning of the fuzzy membership functions will accommodate for physical differences between the platforms. The controller achieves prompt and accurate steering control performance on both a hardware-in-the-loop electrohydraulic steering simulator and on an agricultural tractor.

Abstract: A vehicle (1) provided with a frame having two frame sections (3,4) which are able to tilt with respect to one another. An opposite steer power transmitter (50) is connected to a steerable front wheel (13). The opposite steer power transmitter (50) is controlled as a function of the tilting moment on the frame sections (3,4). By this means, application of opposite steer is achieved, as a result of which the tilting section of the vehicle “drops into the bend” more rapidly and as a result of which increased maneuvrability is obtained. The opposite steer power transmitter (50) can be used on vehicles having an active tilting system with, for example, hydraulic tilting cylinders (9,9′), which are controlled by a sensor depending on the radius of the bend (24). The tilting moment generated by the tilting cylinders (9,9′) can optionally serve as a control signal for the opposite steer power transmitter (50).

Abstract: A hydrostatic steering system of the type including a fluid controller (21) for controlling the flow of fluid from a source (11) to a steering actuator (19) in response to movement of a steering wheel (W). The controller (21) is of the type having a fluid meter (65) including a moveable star member (95), the movement of which corresponds to the flow of fluid to the actuator (19). The controller includes a sensor assembly (125) which senses the movement of the star member (95) and generates an electrical signal (127) representative of the fluid flow through the fluid meter (65).

Abstract: A fluid power assist rack and pinion steering system (12) for a vehicle having steerable wheels comprises a rack (66) connected with steering linkage of the vehicle for, upon movement of the rack, moving the steering linkage to effect turning of the steerable wheels. A rotatable pinion (64) is in meshing engagement with the rack (66). The steering system (12) also includes a control valve (22) comprising a valve core (40) rotatable relative to a valve sleeve (42). A first part (56) connects the valve sleeve (42) for rotation with the pinion (64). A mechanism (38) resists relative rotation between the valve core (40) and the valve sleeve (42) as vehicle speed increases by placing axial force on the valve sleeve. A second part (170) on the valve sleeve (42) resists axial movement of the valve sleeve relative to the valve core (40).

Abstract: For an energy-saving type control, a value of a control low rate QP controlled by a flow control valve V is closer to a value of a flow rate required by an output side such as a power cylinder 8, a steering valve 9 or the like, to suppress a driving torque of a pump P. An excitation current I of a solenoid SOL is specified on the basis of a solenoid current instruction value IT based on a steering torque and a solenoid current instruction value IS defining a standby flow rate.

Abstract: A power machine includes one or more steerable wheels. The wheels are steerable using a hydraulic actuator to drive steering movement of the wheels. The power machine also includes steering angle sensors which sense the steering angle and provide a signal indicative of the angle at which the wheels are disposed relative to a longitudinal axis of the power machine. A hydraulic control system controls pressure of hydraulic fluid provided to the steering actuators based upon the steer angle position and desired change in position over time sensed by the steer angle sensors.

Abstract: In a control valve of a power steering apparatus, mutually adjacent longitudinal grooves are formed at an inner surface of a sleeve, and each upper end of longitudinal grooves is arranged in a stagger layout, and each lower end thereof is arranged in a stagger layout.

Abstract: A hydraulic power steering apparatus 1 which is arranged so that a damper valve 10 is disposed in hydraulic oil circuits 8 and 9 for connecting an oil passage selector valve 11 in a gear box with right and left oil chambers of a power cylinder 6. The damper valve 10 comprises a spool valve. And a control oil chamber 21 of the spool valve 10 is connected with a hydraulic oil feed passage 18 for connecting a hydraulic pump 13 which is driven by an internal combustion engine so as to discharge hydraulic oil, with the oil passage selector valve 11. Its back pressure chamber 17 is connected with a hydraulic oil circulating passage 19 for connecting the oil passage selector valve 11 with a reservoir tank 12. Orifices 27 and 28 are provided in connecting oil passages 22 and 20, such that when discharge oil pressure of the hydraulic pump 13 rises, opening of the spool valve 10 increase.

Abstract: A device for controlling a turning behavior of a vehicle detects running speed of the vehicle, calculate a standard performance of the turning behavior of the vehicle substantially according to a steering angle input by a steering system and the running speed of the vehicle, calculates a deviation of the turning behavior from the standard performance in an amount of decrease of vehicle running speed to be effected with the vehicle for compensating the deviation, calculates a target decrease of engine torque for effecting the vehicle running speed decrease, and decreases the engine torque according to the target engine torque decrease.

Abstract: A way is provided to simulate the steering handle manual torques which correspond to a steering stop of the steered vehicle wheels for a vehicle steering system which can be operated in a normal mode and in an emergency mode. The steering system is capable of being switched between a steer-by-wire level assigned to the normal mode, on which level a steering handle is connected to steered vehicle wheels via an electric or electronic control system, and a fall-back level assigned to the emergency mode, on which level the steering handle is positively coupled mechanically and/or hydraulically to the steered vehicle wheels. The fall-back level is activated in normal mode if the steered vehicle wheels are displaced into the region of the steering stop.

Abstract: A steering system of a non-tracked motor vehicle has steered vehicle wheels are connected in normal operation with respect to the effect with a steering handle only by way of an electronic automatic control unit which continuously monitors itself with respect to a correct operation. As a function of a desired-value generator, which is operated by the steering handle, this automatic control system operates an adjusting drive for the steering adjustment of the steered vehicle wheels. In the event of a malfunctioning of the automatic control system, a forced coupling is automatically switched effective between the steering handle and the steered vehicle wheels. This also takes place if the performance limit of the adjusting drive is reached so that the driver is capable of assisting the adjusting drive by the driver's manual force on the steering handle.

Abstract: A controller for an electric power assisted steering system comprises a drive circuit (2) for controlling current to a motor (1) and a data processor (8) for controlling the motor current and hence assistance torque. A circuit (9) generates a current limit which is a monotonically decreasing function of vehicle speed. A comparator (6) compares motor current with the current limit and switches off the drive circuit (2) if the current limit is exceeded.

Abstract: This invention provides a power steering apparatus for assisting steering by utilizing a hydraulic pump to be driven by an electric motor as a generating source of a hydraulic pressure. A drive voltage determination unit determines a drive voltage so that a rotational velocity of the electric motor detected by a rotational velocity sensor and a rotational velocity detecting circuit becomes a first rotational velocity on the occasion of starting of the electric motor, and determines a gradually increasing drive voltage after the electric motor is started by the determined drive voltage until the detected rotational velocity reaches the second rotational velocity. Therefore, an unnecessary inrush current is not generated in the electric motor, and the rotational velocity of the electric motor does not overshoot.

Abstract: The invention concerns a hydraulic dual circuit steering system with

Abstract: The object of the present invention is to provide a method for limiting the hydraulic maximum pressure of a power-assisted steering system, which permits effective pressure limitation and thus protects the individual elements of the power-assisted steering system, i.e., a pressure limitation not far above the desired maximum operating pressure, but on the other hand does not require an overdimensioning of the individual segments of the power-assisted steering system.

Abstract: A power steering apparatus is provided which is adapted to generate a steering assist force by a hydraulic pressure generated by a pump driven by an electric motor. The apparatus includes: a steering angle detection section (11, S1, S4) for detecting an absolute steering angle on the basis of a steering angle midpoint and a relative steering angle; a first control section (31, S6, S8 to S10) for actuating the electric motor in response to the steering angle detection section detecting an absolute steering angle of not smaller than a first threshold value; and a second control section (31, S6, S11, S9, S10) for actuating the electric motor in response to a steering angle change becoming not smaller than a second thresold value which is smaller than the first threshold value when the absolute steering angle detection is not carried out by the steering angle detection section.

Abstract: A rack-pinion type power steering apparatus includes a cylindrical stub shaft, a torsion bar, a pinion shaft, a rotor, and a sleeve. The stub shaft rotates in a steering body upon a steering operation. The torsion bar has one end fixed at one end of the stub shaft and extends toward the other end of the stub shaft. The pinion shaft is pivotally connected to the other end of the torsion bar and has pinion teeth that mesh with a rack of a steering wheel. The rotor is arranged to cover the torsion bar from the stub shaft along an extending direction of the torsion bar. The sleeve has one end integrally connected to the pinion shaft, extends from the pinion shaft along the stub shaft, and is arranged around the rotor to constitute a rotary type channel selector valve between the rotor and the sleeve. At least two ends of an inner circumferential portion of the sleeve integrally connected to the pinion shaft have slidable contact surfaces that slidably support the rotor integrally connected to the stub shaft.

Abstract: A method sofeware and apparatus for suppressing high-frequency oscillations in the steered axles of a vehicle with a regulating device for regulating a steering angle on the basis of a setpoint that has been calculated. Active steering of this kind has the advantage that driving errors, within the scope of the physically possible, are prevented. However, the disadvantage is that as a result of the regulation of the steering angle, steering stiffness, and running-in behavior of the wheel, high-frequency oscillations of the wheel result around its vertical axis. The development of these oscillations is termed the shimmy effect. The shimmy effect is reliably prevented without adversely affecting the regulating quality of the steering angle by calculating the steering angle rate in a model of the steering and supplied it to the computer as an additional input value.

Abstract: A method for detecting an erroneous travel direction or a defective yaw rate sensor 12 is disclosed. Two estimates of the vehicle yaw rate are gathered from separate criteria and are compared with one another as well as the measured vehicle yaw rate. Using these comparisons along with other information regarding vehicle travel, a conclusion of whether a travel direction signal is erroneous is made. This determination can then be used to modify the vehicle's brake control strategy.