Abstract: A steering apparatus (10) includes a hydraulic power steering gear (130) for turning the steerable wheels (15) of a vehicle. The steering gear (130) includes a closed center valve (150). An electric motor (18) is operatively connected with the steering wheel (12). When activated, the motor (18) resists rotation of the steering wheel (12) to provide steering feel to the vehicle driver and to modulate force applied to the steering wheel (12) upon initial opening of the closed center valve (150).

Abstract: Right-turn and left-turn aimed input shaft drive mechanisms are provided, each comprising a piston unit that slides in a bore formed in an output shaft and a contact surface that is formed on an input shaft. Under normal cruising of a vehicle, a comfortable steering feeling is given by a relatively small counter torque that is produced by a contact between the piston unit and a second inclined surface of the contact surface, and upon stray running of the vehicle due to doze in driving or the like, a relatively large steering torque is produced by a contact between the piston unit and a first inclined surface of the contact surface. An inclination angle of the second inclined surface relative to a traveling path of the piston unit is greater than that of the first inclined surface.

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 controller 38 effects operation of the electric motor 36 to drive the pump 34 to supply fluid to the power steering motor assembly 18 at a flow rate based on the speed of the engine 28.

Abstract: In steering control apparatus and method for an automotive vehicle, a camera photographs a travel path in a traveling direction of a vehicle, a lateral displacement calculating circuit calculates a lateral displacement of the vehicle with respect to the travel path according to an image of the travel path photographed by the camera, a differentiator calculates a differential value of the lateral displacement, a vehicle speed sensor that detects a vehicle speed, a relative yaw rate calculating section calculates a relative yaw rate with respect to the travel path of the vehicle on the basis of the lateral displacement, the differential value of the lateral displacement, and the vehicle speed, an actuator provides an assistance force for the steering mechanism, and an actuator controlling section drivingly controls the actuator in a direction toward which the relative yaw rate is cancelled on the basis of the relative yaw rate.

Abstract: An automotive steering rack stroke adjusting device is disclosed that detects a change in a gap defined between steerable wheels and a vehicle body depending on a change in the stroke of the steerable wheels using a vehicle height sensor, and automatically adjusts the rotation of a plurality of rotary bodies with respect to a stop plate of a steering rack, so that the optimized maximum stroke of the steering rack can be set according to the driving conditions of the vehicle. Furthermore, the present invention is able to increase an adjustment range of the stroke of the steering rack, so that a minimum rotation radius of the vehicle may be reduced, thus markedly enhancing the driving convenience.

Abstract: A hydraulic steering system for a work machine may include a first steering actuator having a first and a second chamber. In addition, the steering system may include a second steering actuator having a third and a fourth chamber. A multi-position directional valve may include at least one low power position and at least one high power position. The low power position may be configured to direct fluid only to the first chamber during a low power turn to extend the first steering actuator. The high power position may be configured to direct fluid to the first chamber and the third chamber during a high power turn to retract the second steering actuator.

Abstract: A power steering system for a vehicle includes a hydraulic system for controlling resistance of a steering wheel. A valve of the hydraulic system is connected to a coil which varies positioning of the valve. A method for controlling the resistance of the steering wheel includes turning the steerable wheels of the vehicle in response to rotation of the steering wheel. The angle of the steering wheel and the speed of the vehicle are sensed and inputted into a controller. A lateral acceleration is determined based on the sensed signals by the controller. A recommended current rate of the coil is determined based on the lateral acceleration. An adjustment to the recommended current rate of the coil is determined based upon the speed of the vehicle. The recommended current rate is also modified based upon the adjustment. The modified current rate of the coil is then applied to the coil to vary the stiffness of the valve, which in turn varies the resistance to turning the steerable wheels of the vehicle.

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: A vehicle steering control system is provided with a steering angle ratio varying mechanism, a variable power assisted steering mechanism and a steering angle ratio controller. The steering angle ratio varying mechanism varies the steering angle ratio, which is the ratio of the turning angle of the front wheels with respect to the steering angle of the steering wheel. The variable power assisted steering mechanism outputs an auxiliary steering force that supplements the steering force of the driver to the steering mechanism for turning the front wheels. The steering angle ratio controller increases the steering angle ratio in a steering angle range in the vicinity of the steering angle center point, and reduces the steering angle ratio in the steering angle range in the vicinity of the rack stopper position, regardless of the steering angular speed of the steering wheel.

Abstract: An apparatus (10) for use in turning steerable vehicle wheels (12, 14) includes first and second piston and cylinder type hydraulic motors (32, 34) which are connected with a central portion of a vehicle. A steering control valve (24) is operable in response to manual rotation of a steering wheel (18) to effect extension and contraction of the first and second hydraulic motors. A rack and pinion steering gear (110, 114) may be connected with a piston rod (86) of one of the hydraulic motors (32). A secondary control valve (200) may be provided to effect operation of one of the hydraulic motors to a greater extent than the other hydraulic motor.

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: The invention relates to a hydraulic steering system (1) comprising a hydraulic steering unit (2) and an auxiliary device (3). Said steering unit (2) feeds a hydraulic medium to a steering cylinder (5) according to the movement of a steering wheel (4). The auxiliary device (3) comprises a valve unit (6) and also feeds a hydraulic medium to the steering cylinder (5) according to the movement of the steering wheel (4), in order to assist the steering movement. The hydraulic medium ejected or discharged from the steering cylinder (5) as a result of the hydraulic medium fed thereinto flows back into a tank (10) or to a pump (8, 9) by means of the steering unit (2).

Abstract: A steering apparatus for a vehicle includes a steering angle measuring unit, a vehicle speed measuring unit, a yaw rate measuring unit, a yaw rate-based reaction force control unit for controlling a steering reaction force depending on an actual yaw rate measured by the yaw rate measuring unit, and a yaw rate deviation-based reaction force control unit for determining a standard yaw rate depending on at least the steering angle and the vehicle speed, calculating a yaw rate deviation between the standard yaw rate and the actual yaw rate, and controlling the steering reaction force depending on the yaw rate deviation, and a primary control unit for executing a control operation such that a degree of contribution of the yaw rate-based reaction force control unit is decreased and a degree of contribution of the yaw rate deviation-based reaction force control unit is increased as the yaw rate deviation increases.

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 steering control apparatus is provided for controlling a steered wheel angle of a wheel to be steered. On the basis of a road coefficient of friction estimated between right and left wheels, a braking force difference between the right and left wheels is calculated. A slip angle—total lateral force characteristic indicative of a relationship between a slip angle and a total lateral force of a wheel to be steered is provided on the basis of the estimated coefficient of friction. Then, a steered wheel angle of the wheel to be steered is set on the basis of the braking force difference and the slip angle—total lateral force characteristic.

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 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: A variable gear ratio hydraulic power steering device 1 is provided with a variable ratio transmission mechanism 7 for varying the rotation transmission ratio between the rotational angle of a steering handle 31 and the rotational angle of a pinion shaft 33 and a flow volume control valve 40 for controlling the discharge flow volume of an oil pump 10 which circulates operating fluid. The variable ratio transmission mechanism 7 has a lock mechanism 75. A valve controlling controller 50 for controlling the flow volume control valve 40 switches main and secondary flow volume control maps for controlling the flow volume control valve 40, in dependence on the operational state of the lock mechanism 75. Thus, a failsafe function for the variable ratio transmission mechanism 7 is given to the variable gear ratio hydraulic power steering device 1.

Abstract: A variable gear ratio hydraulic power steering device 1 is provided with a variable ratio transmission mechanism 7 having a drive motor 70; a flow volume control valve 41 for controlling the discharge flow volume of an oil pump 10 which circulates operating fluid; and a steering angle sensor 310 for measuring a handle steering angle input to a steering handle 31. A valve controlling controller 50 is constructed to take thereinto a measured ACT angle which is the rotational angle of the drive motor 70 and to calculate a target ACT angle for the drive motor 70 based on the handle steering angle. Further, the valve controlling controller 50 controls the flow volume control valve 41 to make the discharge flow volume equal to or greater than a predetermined flow volume when the magnitude of a difference ACT angle which is the difference between the target ACT angle and the measured ACT angle is equal to or greater than a threshold value.

Abstract: The invention provides a method for controlling valve stiffness in a power steering system. The method includes the step of engaging a pinion and a spool shaft with respect to one another for turning at least two wheels of a vehicle in response to rotation of a steering wheel from an on-center orientation. The method also includes the step of variably assisting movement of the pinion with a hydraulic power steering device having a valve movable between a closed configuration and an open configuration. The method also includes the step of moving the valve from the open configuration to the closed configuration in response to rotation of the spool shaft relative to the pinion from an on-center orientation to assist the pinion in rotation for turning the at least two wheels.

Abstract: A hydraulic power steering system for a vehicle includes a first, hydraulic actuator for making available steering power or auxiliary steering power for adjusting the steering angle of one or more steered wheels of the vehicle, and with a second electric actuator for making available a steering power or auxiliary steering power for adjusting the steering angle of the steered wheel. For a power steering system, for which the power dissipated is reduced and the operating temperature lowered, the first hydraulic actuator can be taken out of operation while the vehicle is being driven as a function of the trip and/or vehicle parameters.

Abstract: A vehicle steering system for steering vehicle wheels includes a steering wheel, a steering power assisting unit for providing assisting power when the steering wheel is steered, a transfer ratio control mechanism for controlling the ratio of a steering angle of the steering wheel to a steered angle of the vehicle wheels according to a vehicle condition; a steering torque sensor, a motor control circuit for controlling the driving motor so as to cancel the steering torque applied to the steering wheel when the steering torque sensor detects a steering torque applied to the steering wheel until the transfer ratio control mechanism starts operation. The transfer ratio control mechanism includes a transfer ratio changing mechanism and a driving motor for driving the transfer ratio changing mechanism.

Abstract: A vehicle steering apparatus (10) includes a steering gear assembly (20) which is connected with a steerable vehicle wheel (12). A first sensor (26) has an output signal which is a function of steering wheel position. A second sensor (28) has an output signal which is a function of steerable wheel position. A controller (30) is operable to provide an output signal when the steerable vehicle wheel position does not correspond to the steering wheel position. A motor (34) is connected with a differential gear mechanism (36). The motor (34) is operable in response to the output signal from the controller (30) to effect operation of the differential gear mechanism (36) to actuate the steering gear assembly (20) and change the position of the steerable vehicle wheel (12).

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: In a power steering system employing a power cylinder for steering assistance, hydraulic pressure is supplied through a pair of fluid lines to respective hydraulic chambers of the power cylinder. Check valves are provided to charge a hydraulic pressure in a communicating circuit intercommunicating the two fluid lines. Also provided is a solenoid-actuated directional control valve for relieving the hydraulic pressure charged in presence of a power steering system failure. An opening of the directional control valve varies depending on a solenoid attracting force and a pressure differential between the hydraulic pressure in the communicating circuit and hydraulic pressure in a reservoir. A relatively low exciting current is applied to the solenoid when the hydraulic pressure charged exceeds a predetermined pressure value. A relatively high exciting current is applied to the solenoid when the hydraulic pressure charged is less than or equal to the predetermined pressure value.

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 servo-steering valve for a hydraulic servo-steering arrangement has an input shaft, an output shaft, a torsion rod which biases the input shaft and the output shaft relative to each other into a central position, and a valve which consists of a valve sleeve and a valve shaft which with a rotation of the input shaft relative to the output shaft are rotated relative to each other. An adjustment drive is provided, which can rotate one component of the servo-steering valve with respect to another, so that a superimposition value is superimposed on an input value which is given through the actuation of the input shaft.

Abstract: In steering control for individually controlling wheel steering angles ?1, ?2, ?3, and ?4 of a vehicle in accordance with a condition equation for forming a prescribed mode, one of the condition equation variables is used as a steering command value S. In a process for changing the command value S from a value S1 to a value S2, for transitioning the steering angles ?1, ?2, ?3, ?4 from values [?1, ?2, ?3, ?4]S1 corresponding to the steering command value S1, to values [?1, ?2, ?3, ?4]S2 corresponding to the steering command value S2, the steering angles ?1, ?2, ?3, ?4 are changed toward incremental transition steering angles [?1, ?2, ?3, ?4]S1+?S corresponding to a steering command value (S1+?S), which is the steering command value S1 to which an incremental steering command value ?S has been added.

Abstract: In a hydraulic power steering apparatus, when the relative rotation between input and output shafts which are connected by a torsion bar is converted into the relative rotation between an outer valve element and an inner valve element, the ratio of the relative rotation angle of the latter to the relative rotation angle of the former is varied in accordance with an operating condition of a vehicle. The hydraulic pressure to generate steering assist force is controlled in accordance with the relative rotation angles between both valve elements. The outer valve element is capable of relative coaxial rotation to the input and output shafts, and the inner valve element is formed integrally with the input shaft. A swinging member is supported by first, second and third supporting parts which respectively rotate together with the input shaft, the output shaft or the outer valve element.

Abstract: A servo-assisted steering system for a motor vehicle, in which the steering system includes a steering wheel for presetting a desired steering angle for the wheels of the motor vehicle, a driving-dynamics means for superimposing a correction angle on the steering angle, the 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. To keep the efficiency of the driving-dynamics means nearly constant over the entire road-speed range of the vehicle, the servo drive is implemented as a variable torque assistance system, the degree of torque assistance being dependent on the road speed of the vehicle and on at least one variable of the driving-dynamics means that characterizes the correction angle.

Abstract: In a power steering device comprising a power steering pump, and to a method for operating a power steering device for a vehicle comprising a hydraulic circuit provided with a rotary slide valve, a steering cylinder and a control valve for adjusting the volume flow of a hydraulic medium as required for steering assistance, the control valve is arranged on the pressure side of the pump in such a way that it divides the volume flow (Q) from the power steering pump into at least a first base partial flow (A) and a second controlled partial flow (B), the base partial flow (A) being independent from the operating state of the control valve and always available for steering assistance, whereas the partial flow (B) is dependent on the operating state of the control valve.

Abstract: An electric power steering control device includes a memory. The memory is accommodated in the electric power steering control device mounted on a vehicle, and permits rewrite and storage of data. Transmitting a signal from an external of the vehicle allows the data stored in the memory to be rewritten.

Abstract: A flow controlling apparatus for a power steering system includes a variable throttle mechanism installed in the pump to change the flow rate of discharged oil from the pump to a hydraulic device; a linear solenoid mechanism controlling the variable throttle mechanism by a predetermined energizing current; a spool feeding back the excess discharged oil to a bypass passage of the pump in accordance with a differential pressure between the upstream and downstream sides of the variable throttle mechanism when the excess fluid exceeds a predetermined value; and an ECU controlling the energized current to change the transition process in accordance with a steering angular velocity of the steering wheel.

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: 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: A steering characteristic control apparatus and method for a vehicle is disclosed which can carry out behavior control of the vehicle regarding a steering characteristic and so forth appropriately in accordance with the type of turning and the road surface situation. To this end, if the steering characteristic of the vehicle is placed into an oversteer or understeer state exceeding a reference level, then the control end condition when the steering characteristic is controlled to the neutral steer side by control of a braking mechanism is set in accordance with an estimated road surface ? state and the type of turning (steady turning or non-steady turning) of the vehicle. Upon steady turning, during traveling on a low ? road, it is set as the control end condition that the stability of the vehicle behavior is restored sufficiently, but during traveling on a high ? road, it is set as the condition that the stability of the vehicle behavior is restored to some degree so that the control can be ended rapidly.

Abstract: A power steering system includes a reversible pump for supplying hydraulic fluid to pressure chambers of a power cylinder through first and second passages, an assisting-force detector for detecting a steering assisting force to be provided to a steering wheel, a motor control circuit outputting a drive signal to an electric motor in accordance with the detected steering assisting force so as to obtain a desired hydraulic pressure, a communication passage for providing fluid communication between the first and second passages, a solenoid valve for switching between communication and interruption of the communication passage, and a current detector for detecting a current passing through an energization circuit of the solenoid valve and between the solenoid valve and a ground.

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: A steering input device for a steer-by-wire system is provided. The input device comprises a first shaft and a hand wheel. The first shaft is rotatably installed in a first housing. The hand wheel is connected to the first shaft such that the hand wheel and the first shaft drive one another. The hand wheel has a range of motion of between about ±45 degrees and about ±90 degrees. The hand wheel also has an outer dimension of about 12 inches. The range of motion and the outer dimension allow the steering input device to be installed in a vehicle in a non-conventional position relative to a twentieth century conventional position including at least one of the hand wheel extending from the first shaft extending along a length defining the vehicle on one of two sides thereof and the hand weel extending rearward in the vehicle farther than an instrument panel.

Abstract: A vehicle steering control system is provided which is capable of reliably protecting a motor for driving a wheel steering shaft. In the system, a current sensor and a motor rotational speed detection section respectively detect a current applied to the steering shaft drive motor and the motor rotational speed of the steering shaft drive motor, and current inference means infers the motor current applied to the steering shaft drive motor based on the detected motor rotational speed. Abnormal judgment means compares the current inference value obtained by the current inference means with a current detection value indicated by the current sensor to judge whether the current sensor is normal or not. Abnormal judgment output means outputs the result of the abnormal judgment when the current sensor is judged to be abnormal. When a trouble occurs that the current sensor fails to operate normally due to the malfunction or the like, such a trouble can be recognized at the early stage of the malfunction.

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 cable-type steering device in which the steering gear ratio can be varied in accordance with the position of a steering wheel comprises operating cables wound around an outer peripheral surface of a driving pulley rotatably connected to a steering wheel and an outer peripheral surface of a follower pulley rotatably connected to a steering gear box for steering wheels so that a steering torque input to the steering wheel is transmitted through the operating cables to the steering gear box. The driving pulley is of a barrel-shape with the diameter being larger at an axially central portion and smaller at axially opposite ends. The follower pulley is of a bobbin-shape or sand-clock-shape with the diameter being smaller at an axially central portion and larger at axially opposite ends. Thus, the steering gear ratio (a ratio of the steering angle of the steering wheel/a transmitted steering angle for the wheels) can be varied in accordance with the position of the steering wheel.

Abstract: A power steering system capable of giving a driver no discomfort even when an incoming current instruction value sharply decreases. The power steering system comprises a controller C for determining a solenoid current instruction value SI on the basis of a current instruction value I1 in accordance with a steering angle supplied from a steering angle sensor, a current instruction value I2 in accordance with a steering angular velocity, and a current instruction value in accordance with a vehicle speed. The controller C comprises a delay control section for reducing the rate of decrease only when the incoming current instruction value sharply decreases and outputting the resulting current instruction value.

Abstract: The invention relates to a method for compensating steering-torque disturbances caused by unequal torque distribution at the front wheels of a motor vehicle with front-wheel drive or all-wheel drive and an active differential. In this arrangement, the magnitude of the steering-torque disturbance is determined from the torque distribution, the total torque and the steering lever and a compensation torque is exerted on the steering system by means of an active steering-servo device.

Abstract: A power steering system capable of preventing an unnecessary standby flow produced in high speed travel. A controller C determines a basic current instruction value Id based on a current instruction value I1 in accordance with a steering angle detected by a steering angle sensor 14, a current instruction value I2 in accordance with a steering angular velocity and current instruction values I5, I6 in accordance with a vehicle speed, and adds a standby current instruction value Is to the basic current instruction value Id, and outputs the resultant value of the addition as a solenoid current instruction value SI, and changes the standby current instruction value Is on the basis of the vehicle speed.

Abstract: Provision of a power steering system capable of giving a driver no discomfort during high-speed travel. A controller calculates or stores a current instruction value I1 in accordance with a steering angle supplied from a steering angle sensor and a current instruction value I2 in accordance with a steering angular velocity; performs multiplication of the steering angle base current instruction value I1 and the steering angular velocity base current instruction value I2 by current instruction values I5, I6 set based on a vehicle speed, respectively; applies current instruction values I7, I8 in accordance with the vehicle speed serving as limit values to the corresponding steering angle base and steering angular velocity base current instruction values resulting from the multiplication; selects a larger value of the two current instruction values below the limit values; and determines the selected value as a solenoid current instruction value SI.

Abstract: A method of controlling a power steering system having an adjusting mechanism for adjusting at least one vehicle wheel is disclosed herein. The system includes a steering wheel, a position sensor, and a drive system, such as a servo pump driven by an electric motor, to provide steering assistance a steering wheel and a position sensor. It is determined whether the adjusting mechanism is approaching an end position. If it is found that the adjusting mechanism is approaching the end position, then the drive system is controlled in such a way that it provides a diminishing steering assistance.

Abstract: A variable displacement pump is provided. A pump body has an outer ring defining an inner cavity, where the inner cavity further defines a pump suction path and a pump discharge path in fluid communication with the inner cavity. A cam ring is pivotably supported in the inner cavity by a pivot pin formed on a portion of an inner diameter of the adapter ring. An actuated cam is formed on the cam ring. An actuator is linked through the actuated cam to the cam ring for moving the cam ring in a pivotable motion. A control module is linked to the actuator.