Abstract: The present embodiments relate to a steer-by-wire-type steering apparatus, and may provide a steer-by-wire-type steering apparatus comprising: an outer member which is rotated by a driving motor and has oblique grooves formed in the inner circumferential surface thereof; an inner member which is formed in a cylindrical shape and spaced inward from the inner circumferential surface of the outer member, fixed to a steering column, and provided with a guide part open in a radial direction; a sliding member, of which the outer surface is supported by the oblique grooves when the outer member rotates, and which moves along the guide part in an inward radial direction; and a support member which moves in the radial direction in association with the sliding member, and which supports the outer circumferential surface of the steering shaft and thereby prevents the steering shaft from rotating.

Abstract: A method for operating a steering system includes providing an electromechanical steering assistance having several redundant control paths. Each control path includes a control unit, a power unit and a winding circuit of a servomotor. A correcting-variable unit is provided in each control unit in order to make a correcting variable available, depending on input variables. The correcting variables of all of the correcting-variable units are averaged. A set correcting variable is made available by each control unit, depending on the averaged correcting variable. A device for operating a steering system and a steering system for steering wheels of a motor vehicle, are also provided.

Abstract: A vehicle steering control method includes receiving a sensed handwheel angle corresponding to a position of a handwheel and receiving a sensed handwheel toque value indicating an amount of torque applied by an operator on the handwheel. The method also includes, in response to a determination that the handwheel motor is in an unlocked condition, generating a roadwheel angle based on the sensed handwheel angle and a vehicle speed. The method also includes, in response to a determination that the handwheel motor is in a locked condition generating the roadwheel angle based on the sensed handwheel torque value and the vehicle speed and, in response to a determination that the locked condition of the handwheel motor is an intermittent condition, maintaining the handwheel motor in the locked condition.

Abstract: A steering system includes a housing, a steering operation shaft that is housed in the housing and configured to move in an axial direction to steer right and left steered wheels, a first drive source that generates a first drive force, a second drive source that generates a second drive force, a first power transfer unit that applies an axial force to the steering operation shaft with the first drive source, a second power transfer unit that applies an axial force to the steering operation shaft with the second drive force, a position detection sensor that is provided in the housing and detects an axial position of the steering operation shaft, and a control device that controls the first drive source and the second drive source using a detection result of the position detection sensor.

Abstract: A vehicle includes a rear steering system and a front differential hydraulic drive system. A first front drive control valve is operable to output a defined fluid flow in response to a steering command input. A second front drive control valve is operable to selectively divert a portion of the defined fluid flow output from the first front drive control valve. When the vehicle is operating in a pre-defined condition, a steering controller may control the second front drive control valve to divert a portion of the defined fluid flow from the first front drive control valve to define a reduced fluid flow, which is communicated to the front differential hydraulic drive system, to reduce a steering ratio of the front differential hydraulic drive system relative to the rear steering system, to desensitize steering provided by the front differential hydraulic drive system.

Abstract: An apparatus is provided for measuring a torque in a force-feedback actuator for a steer-by-wire steering system has a housing element, a control unit, a drive apparatus, and a transmission apparatus to be coupled to a steering device. At least one motion sensor detects a motion of the transmission apparatus relative to the housing element and provide a motion signal resulting from the motion to the control unit. The transmission apparatus is coupled to the housing element by way of at least one reset-reversible adjusting device which has at least one mechanical property. A torque of the transmission apparatus, and thus of a connectable steering device, may be ascertained by the control unit using the at least one mechanical property, which has at least one changing state value during the movement of the transmission apparatus, in combination with the motion signal.

Abstract: A method for determining whether the driver of a vehicle is holding the steering wheel includes steps of repeatedly determining (S1) the steering wheel angle, repeatedly determining (S2) an error value based on a current determined steering wheel angle value and a previously determined steering wheel angle value; comparing (S3) a determined current error value with previously determined error values to determine a correlation between the error values; determining (S4a) that the driver is holding the steering wheel if the correlation between the error values is above a threshold value or if the driver is not holding the steering wheel if the correlation between the error values is below a threshold value. Also, a system for determining whether the driver of a vehicle is holding the steering wheel by performing the method. Also a computer program and a computer program product for practicing the method.

Abstract: A steer-by-wire system includes a steering reaction torque generation device mechanically separated from a turning device for turning wheels and configured to apply a reaction torque to a steering wheel. The steering reaction torque generation device has a duplex configuration including a first system and a second system, each system including a reaction torque motor. When both systems are normal, a control device generates the reaction torque having a normal characteristic by controlling an operation of the reaction torque motor of at least one system. In a case of single failure where one of the systems fails, the control device generates the reaction torque having a first characteristic by controlling an operation of the reaction torque motor of another of the systems. The reaction torque having the first characteristic is different from the reaction torque having the normal characteristic with respect to a same steering angle.

Abstract: A vehicle, a single-wheelset/double-wheelset trackless train and a tracking and steering control method therefor are provided in the invention. The method includes the following steps. During traveling of the vehicle, steering information of the vehicle is continually collected by the controller. Information about a guiding front wheel turning angle, a controlled rear wheel turning angle, a vehicle body position angle, an included angle between vehicle bodies, and a vehicle travel time and speed is collected; an interval for data collection is determined according to a distance between a guiding front wheel and a controlled rear wheel; and when the controlled rear wheel travels to a certain point near a front wheel travel track, the controlled rear wheel is controlled to travel in a travel direction same as that when the front wheel travels to the point.

Abstract: A steering column assembly includes a steering shaft operatively coupled to a steering device, the steering shaft and the steering device having corresponding rotation with each other. Also included is an anti-rotation assembly selectively engaged with a surface of the steering shaft to maintain the steering shaft and the steering device in a stationary condition when the steering shaft is rotationally decoupled from road wheels operatively coupled to the steering shaft.

Abstract: A steering device for a steerable machine, particularly a construction machine, comprising a steering element for manual input of steering commands, a steering actuator for driving a steering adjustment of a travel unit of the construction machine, and a transmission device, which is arranged between the steering element and the steering actuator, the transmission device including an actuator orbitrol for driving the steering actuator. Furthermore, the invention relates to a construction machine having such a steering device, as well as to a method for steering a steerable machine, particularly a construction machine.

Abstract: A method for adapting an actual steering wheel angle of a steering wheel and an actual wheel steering angle of a wheel steering system in a motor vehicle after an automated driving maneuver has been executed. The method includes detecting the actual steering wheel angle by a steering wheel angle-detection device and the actual wheel steering angle by a wheel steering angle-detection device, adapting the actual steering wheel angle by a steering wheel-actuation device and/or the actual wheel steering angle by a wheel steering-actuation device based on a transfer strategy within a predefined transfer time. Also disclosed is an associated device.

Abstract: An ECU monitoring system includes: an ECU that includes an input interface unit, a computer unit, and an output interface unit; a storage unit that stores a normal input signal and a normal output signal; a comparing unit that calculates a compared difference by comparing the current input signal with a previous input signal stored in the storage unit, and outputs an alarming signal showing the current input signal is abnormal, when the compared difference is out of a predetermined range; and a circulator that receives the output signal, provides the output signal when the output signal is a normal output signal, and provides a normal output signal to the output interface unit, instead of the output signal outputted from the computer in response to the abnormal input signal, when receiving the alarming signal from the comparing unit.

Abstract: One of a condition affecting a vehicle and a planned action of the vehicle are identified. An instruction is provided to actuate movement of a steering wheel in the vehicle, wherein the movement is determined according to the one of the condition and the planned action.

Abstract: In a hybrid power steering system, two steering assisters for supporting a steering force when the driver operates the steering wheel. The steering supporting force can be divisionally used according to the increase of speed and weight of a vehicle, thereby reducing the load applied to any of the steering assisters such that operating noise can be reduced and the endurance can be increased. Further, a motor of a lower power specification may be used even in the case of a truck or a bus that requires a relatively high steering force as compared to a passenger vehicle. Accordingly, production costs can be reduced and a sufficient steering supporting force can be obtained, thereby improving the driver's convenience, and enhancing fuel efficiency while increasing energy efficiency. Further, the steering can be safely maintained even when one of the steering assisters is not operating normally while the vehicle is being driven.

Abstract: The present invention discloses a dual steering system including a first front wheel and a second front wheel, a lateral steering linkage connecting the first and second front wheels, a first steering system with a first steering wheel and a power steering module that assists steering inputs applied to the first steering wheel, and a second steering system with a second steering wheel and a torque sensor in communication with the power steering module of the first steering system and monitoring steering inputs applied to the second steering wheel, whereby the power steering module may provide power assist to the steering inputs applied to the second steering wheel.

Abstract: The motor vehicle of the invention is provided with at least three wheels and includes a driving cab capable of accommodating a single person in the width direction. The motor vehicle comprises a bend-balancing means that acts by the inclination of at least the portion of the chassis that bears the driving cab. According to the invention, the vehicle is also provided with speed, acceleration and/or inclination sensors, and the balancing means are automatically controlled when the information supplied by the sensors is lower than a main predetermined threshold. The invention also provides that the automatic control of the balancing means is deactivated when the information provided by the sensors is higher than said main threshold.

Abstract: In normal times, a rotation angle restriction mechanism in a first state restricts a rotation angle of a steering member within a first rotation angular range. In the event of a failure, that is, when there is a malfunction in a steering angle sensor, the rotation angle restriction mechanism is switched into a second state by an electromagnetic clutch, and the rotation angle of the steering member is restricted within a second rotation angular range. A steering direction is detected on the basis of at which one of a pair of terminal ends of the second rotation angular range, the steering member is located. An ECU executes drive control on a steering system actuator on the basis of the detected steering direction.

Abstract: A pulse active steering control system and method for use in a motor vehicle for improving vehicle stability by reducing a likelihood for rollover and/or skidding sends pulses to the steerable wheels whenever a rollover coefficient and/or the difference between the estimated and actual yaw rate is outside a predetermined range. The pulses are asymmetrical in the form of a smooth curve with a gradually increasing rapid rising edge and a slower falling edge and provide steering input that, along with the driver steering input, returns the rollover coefficient and/or yaw rate to the predetermined range to reduce the likelihood of rollover and/or skidding.

Abstract: An apparatus (10) for use in turning steerable vehicle wheels (14, 16) includes a hydraulic power steering motor (12). A pump (26) having an outlet port (28) is connected in fluid communication with the power steering motor (12) and operable to supply hydraulic fluid to the power steering motor (12). A continuously variable transmission (50) is connected with the engine of the vehicle and the pump (26). The continuously variable transmission (50) is operable to drive the pump (26) at a first speed when the pressure at the outlet port (28) is at a first pressure. The continuously variable transmission (50) is operable to drive the pump (26) at a second speed when the pressure at the outlet port (28) is at a second pressure different than the first pressure. The first speed at which the pump (26) is driven is greater than the second speed.

Abstract: A steering system includes a steer-by-wire (SBW) valve, a main steering pump, a steering actuator, and a steering control unit (SCU). The SCU is in fluid communication with the actuator via a pair of fluid conduits, and includes upper and lower portions. The upper portion contains a first solenoid valve and a cross-over check valve assembly. The lower portion contains a fluid control valve. An ECU generates a steering input signal in response to steering wheel rotation, and transmits the signal to the SBW valve. The SCU controls the first solenoid valve to deliver fluid from the lower portion to the actuator via the cross-over valve assembly in an emergency steering mode, and also controls the first solenoid valve to prevent flow into the actuator and allow recirculation of fluid within the lower portion in a torque feel mode.

Abstract: A system and method for managing faults occurring in a power steering system in a vehicle is disclosed that has particular application for an MRHPS system to provide reliable functioning of the power steering system. The method includes detecting a fault condition in the MRHPS system and selecting a safe mode from a plurality of predetermined safe modes based on the fault condition. The plurality of predetermined safe modes include a normal operation mode, an engine speed follow mode, a manual mode, a fixed duty cycle mode and a voltage control mode. If a fault condition is detected, the method applies the safe mode to manage the fault condition.

Abstract: A target value for yaw angle velocity gain is computed according to a map expressing a relationship between steering wheel angle and yaw angle velocity gain predetermined such that a direction as seen from a driver of a target destination point for vehicle travel at a predetermined time after a forward gaze and a direction as seen from the driver are caused to match each other, and a steering gear ratio is controlled accordingly. A target value for a steering wheel torque corresponding to the detected steering wheel angle and the acquired yaw angular velocity is set, based on a relationship between yaw angular velocity and resistance-feel level predetermined such that the resistance feel level for a driver monotonically increases with increasing yaw angular velocity. Control is then preformed so as to realize the steering wheel torque target value.

Abstract: When the magnitude |?| of a steering angular velocity w is equal to or greater than a determination angular velocity ?th, an electric motor is estimated to be in a predetermined power use state, and a restriction determination threshold Vonth is set to a first voltage value V1. When the magnitude |?| of the steering angular velocity ? is less than the determination angular velocity ?th, the restriction determination threshold Vonth is set to a second voltage value V2 (>V1). When a state in which a power supply voltage Vx is lower than the restriction determination threshold Vonth continues for a predetermined time t1, a power use restriction instruction is output to specific vehicle electrical loads. Thus, power restriction is properly imposed on the vehicle electrical loads, whereby a delay in control of the electric motor is prevented, and excessive imposition of power restriction is prevented.

Abstract: A steer-by-wire steering system includes a steering motor, a steering power transmitting mechanism for transmitting a rotation of the steering motor to a steering axle, a toe angle adjusting motor and a toe angle adjusting power transmitting mechanism for adjusting the toe angle upon rotation of the toe angle adjusting motor. A switching mechanism is provided which operates in such a manner that in the event of failure of the steering motor, the rotation of the toe angle adjusting motor in place of the steering motor is transmitted to the steering power transmitting mechanism to enable a wheel turning, but in the event of failure of the toe angle adjusting motor, the wheel turning is carried out only by the steering motor. A hollow motor is employed for one or both of the steering motor and the toe angle adjusting motor.

Abstract: A vehicle by-wire steering system includes a hydraulic default level. A hydraulic feed unit and a hydraulic actuating unit can be connected together by two hydraulic lines such that when an actuator is non-functional, a steering wheel rotational angle is transformed into a corresponding wheel steering angle by the hydraulic feed unit and the hydraulic actuating unit. The hydraulic lines can be connected together by a switchable steering valve, which is designed as a proportional servo valve, of which the flow cross section can be adjusted in essence continuously between the two extremes of completely closed and completely open.

Abstract: A hydraulic power steering system for a vehicle, e.g., an electrohydraulic power steering system for a motor vehicle, includes a servo valve, the relative movement of whose control parts actuates a piston rod of a servo cylinder and changes at least one steering angle of a wheel which is operatively connected to the piston rod, and additionally has an electric servo motor which drives a rack with the servo cylinder for adjusting the steering angle of the wheel in the same direction. In order to provide an electrohydraulic power steering system which is as compactly arranged as possible in the region of its actuator and may be used flexibly for different classes of vehicle, the action of the rack and the piston rod of the servo cylinder is combined, in a parallel arrangement with one another, on an addition member for jointly adjusting the steering angle of the wheel.

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 vehicle steering system includes a steering wheel, a steering angle detector that detects a steering angle of the steering wheel, a steering angular speed calculator that calculates a steering angular speed of the steering wheel, a vehicle speed detector that detects a vehicle speed, a target rudder angle finding device, a modifying device, and an actuator. The target rudder angle finding device finds a target rudder angle based on the steering angle, the steering angular speed and the vehicle speed. The target rudder angle is a sum of a proportional term proportional to the steering angle and a differential term proportional to the steering angular speed. The modifying device modifies the differential term when the steering angular speed is negative to reduce a value of the differential term from that when positive. The actuator turns at least one wheel of the vehicle in accordance with the target rudder angle.

Abstract: A steering apparatus (10) for turning steerable wheels of a vehicle in response to rotation of a vehicle steering wheel (12) comprises a first assembly (16), a second assembly (26), and a mechanism (108). The first assembly is operatively coupled to the steering wheel and includes components (18, 22) for monitoring applied torque and angular rotation of the steering wheel. The second assembly includes a steering gear (34) and components (28, 30) for actuating the steering gear in response to the monitored rotation. The mechanism, when in a first mode of operation provides a mechanical connection between the steering wheel and the steering gear. The mechanism when in the second mode of operation, providing a mechanical connection between the steering wheel and the steering gear sufficient to enable manual actuation of the steering gear and permit actuation of the steering gear in response to the monitored steering wheel rotation.

Abstract: A steering control apparatus includes a rack shaft connected to steerable wheels and having rack teeth in a given axial range, a first steering mechanism having a reduction gear and a first electric motor to apply a drive force to the rack shaft through the reduction gear, a second steering mechanism having a second electric motor, a power cylinder equipped with hydraulic pressure chambers, an oil pump driven by the second electric motor to provide a supply of hydraulic oil to the hydraulic pressure chambers such that the power cylinder applies a driving force to the rack shaft in accordance with a pressure difference between the hydraulic pressure chambers and a switching unit capable of selectively switching the supply of hydraulic oil from the oil pump to the hydraulic pressure chambers, and a control device that controls the first and second electric motors in response to a driver's steering operation.

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 torque control element for a steering system in a motor vehicle, and such a steering system are provided. The torque control element includes at least two electrical units, each of the electrical units being assigned a separate power supply unit, connected via at least one fuse.

Abstract: A vehicle steering device and control method for use in steer-by-wire steering systems. A steering instrument is operable to receive input from a driver and a turning device is operable to turn at least one wheel. A selectively engageable backup clutch is positioned between the steering instrument and the turning device. Engagement of the backup clutch results in a mechanical connection between the steering instrument and the turning device for assisting control of the at least one wheel, and release of the backup clutch results in a separation of the steering instrument and the turning device for steer-by-wire control of the at least one wheel. A controller is operable to switch from the steer-by-wire control to the assisting control when the backup clutch engages during operation of the steer-by-wire control.

Abstract: An apparatus for steering a vehicle includes a hand steering device, a road wheel steering device, a steering motor and a connection device. The hand steering device is a device which a driver of the vehicle manipulates for steering road wheels. The road wheel steering device actuates the road wheels. The steering motor, which is attached to the road wheel steering device, produces an assist force for the road wheels. The connection device selectively connects and disconnects the hand steering device and the road wheel steering device. In the apparatus, a ratio of a displacement made by the hand steering device to a displacement generated by the road wheel steering device increases as a speed of the vehicle becomes greater while the vehicle is traveling in a predetermined range of speed, and a gradient of the ratio is adapted to be greater when the speed is lower.

Abstract: A vehicle steering control apparatus has a steering wheel, a steering mechanism mechanically separate from the steering wheel for steering the left and right front wheels and a reaction force motor for imparting an operation reaction force against the steering wheel. A steering motor is provided to impart a turning force to the steering mechanism, while a clutch is provided to mechanically connect and disconnect the steering wheel to and from the steering mechanism. A drive torque detector is provided to detect a drive torque imparted to the steering reaction force actuator. A torque sensor is provided to detect an operating torque imparted to the steering wheel. A clutch connection determiner determines that the clutch is in a connected state when a drive torque direction detected by the drive torque detector and an operating torque direction detected by the operating torque detector are different.

Abstract: A steering control apparatus is provided, including a steering wheel, steered wheels, a direction varying actuator to operate the steering control wheels, a steering reaction actuator to apply steering reaction torque to the steering wheel and steering controller. The steered wheels are mechanically disconnected from the steering wheel. The steering controller outputs control commands for controlling the direction varying actuator and the steering reaction actuator.

Abstract: A vehicle steering control apparatus includes a steering wheel to be operated by a driver, a steering mechanism for turning the front wheels in accordance with an operating torque of the steering wheel, and a clutch for mechanically connecting the steering wheel to the steering mechanism. A clutch engagement command issuing section is provided for issuing an engagement command to the clutch when the clutch is disengaged and a condition for engaging the clutch is satisfied. A clutch engagement determining section is provided for determining that the clutch is in an engaged state when an increase in torque is detected at the steering wheel after the engagement command has been issued to the clutch.

Abstract: A steering control system comprises a steering component, a turning component, and a backup mechanism for alternately mechanically separating and linking steering and turning components. A steer-by-wire control unit is provided for executing steer-by-wire control of a turning actuator to a turning angle corresponding to a steering condition and control of a steering reaction force actuator for imparting steering reaction force corresponding to the turning condition. A steering assistance control unit is selectively linked to the backup mechanism to executing steering assistance control for at least one of the steering reaction force actuator and the turning actuator. A control switching unit is provided for controlling a shift, under predetermined conditions, between control by the steer-by-wire control unit and control by the steering assistance control unit.

Abstract: A vehicle steering apparatus with improved safety securely detects whether or not a backup system is operable and comprises a steering shaft connected to the steering wheel; a reaction actuator connected to the steering shaft for adding a reaction force; a rack for steering a steered wheel; a steering actuator provided on the rack; a backup mechanism for connecting the steering shaft and the rack via a clutch, a first detection means or mechanism for detecting the condition of the steering shaft, a second detection means or mechanism for detecting the condition of the rack, and a backup operation monitoring means or mechanism for driving the steering actuator when the power source is energized, the backup operation monitoring means or mechanism selectively monitoring the operation of the backup mechanism based on the value detected by the first detection means or mechanism or the second detection means or mechanism or both.

Abstract: To reduce the length in an axis direction of a steering unit and consequently to provide a vehicle steering apparatus with superior vehicle mountability, a steering apparatus for a vehicle has a steering unit, a reaction generating unit and a steered unit. The steering unit and the steered unit are mechanically separated. The apparatus includes a clutch that mechanically connects the steering unit and the steered unit, and a backup unit is provided between the clutch and the steered unit and transmits steering torque that is inputted from the steering unit, when the clutch is engaged, to the steered unit. A rotation conversion unit that outputs rotation in a rotation axis direction of the clutch that is different from the axis direction of the steering unit is provided between the reaction generating unit and the clutch.

Abstract: In a vehicle steering control device, a steering torque estimation unit estimates steering torque of a steering wheel based on driving current of an electric actuator; a torque sensor detects the steering torque of the steering wheel; an electric power assist unit is controlled based on the steering torque detected by the torque sensor; and a comparison unit compares the torque detected by the torque sensor with the steering torque estimated by the steering torque estimation unit. The electric power assist unit is controlled based on the estimated steering torque in place of being controlled based on the torque detected by the torque sensor when the torque sensor is judged to be abnormal, based on a comparison.

Abstract: The present invention provides a controller of an electric power steering device which does not apply an uncomfortable feeling to a operation of steering wheel while securing a fault determination confirming period enough long to prevent an erroneous detection of a torque sensor fault, and can secure a safety operation of steering wheel, even in the case that an output value of a torque sensor detecting a steering torque of a steering wheel becomes abnormal.

Abstract: A steering control device in which a steering portion including an electric steering reaction force actuator and a steered portion including an electric steered portion actuator are mechanically disconnectable and connectable via a backup connection. Steer-by-wire control disconnects the backup connection and uses control of the steered portion actuator to set a steered angle corresponding to the steering condition and using control of the steering reaction force actuator to add a steering reaction force corresponding to the steered condition. Steering assistance control connects the backup connection and adds a steering aid force using at least one of the steering reaction force actuator and the steered portion actuator. The power supply capacity of a steered vehicle is selectively estimated and if the estimated power supply capacity reaches a predetermined value or below during the steer-by-wire control, steering is switched to the steering assistance control.

Abstract: A vehicle steering control device is provided that suppresses changes in the steering force accompanying the shock transmitted from the road surface during the steering wheel return operation. The vehicle steering device is a steer-by-wire steering device where a steering wheel receiving the steering input which is transmitted electronically to the steering unit which turns steered road wheels of the vehicle. The steering reaction force correction (Gf×F) corresponding to road surface reaction force F is applied to the steering wheel. The device includes a turn/return sensor that senses turn/return of the steering wheel, and during return of steering wheel, road surface reaction force feedback gain Gf is made smaller than the initial turning.

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

Abstract: A steering apparatus for a vehicle is set to a steer-by-wire mode with an electromagnetic clutch being in a disconnected state. In response to steering operation applied to a steering wheel, first and second electric motors turn left and right front wheels. When a failure arises in one of first and second turning control systems including the first and second motors, the turning characteristic of the left and right front wheels is gradually changed from a turning characteristic for steer-by-wire to that for steer-by-mechanical connection. When a failure arises in the first and second turning control systems or after the turning characteristic is changed, the electromagnetic clutch is brought into a connected state, whereby the steering apparatus is switched to a steer-by-mechanical connection mode. Even when the steer-by-wire mode is switched to the steer-by-mechanical connection mode, a driver is not given an unnatural sensation, and excellent steering stability is maintained.

Abstract: A vehicle steering system is disclosed that includes a steering portion, a steered portion, and a clutch mechanism. The steering portion includes operations input mechanism and a reaction adding device. The steered portion includes steering controlled wheels and a steered force adding device. The clutch mechanism mechanically connects the steering portion and steered portion through an engagement. The clutch mechanism has a permanent magnet and an electromagnetic coil so as to form an electromagnetic clutch that releases when a current is applied such that a magnetic force in the direction that cancels a magnetic force of the permanent magnet is generated for the electromagnetic coil. The electromagnetic clutch engages when a current is not applied to the electromagnetic coil.

Abstract: A drive train for a compressor and a hydraulic pump of a motor vehicle, and a method of use are described. The system includes a hydraulic power steering system, an electric superimposed steering system for providing steering assistance, and a motor vehicle drive motor with a common output shaft for driving the compressor and the hydraulic pump. Also provided are means for reducing the power which is supplied to the compressor and to the hydraulic pump via the output shaft, when demands made of the compressor and of the steering assistance system permit reduced power operation. The power which is supplied to the compressor and to the hydraulic pump via the output shaft may be reduced substantially to zero when operation of the compressor is unnecessary and the electric superimposed steering system is sufficient to provide alone the steering assistance.

Abstract: A steering apparatus for a steerable vehicle includes a steering unit, an operating unit, a backup unit, and a control unit. The backup unit selectively connects/disconnects the steering unit and the operating unit. The control unit is operable in two control modes including an SBW mode and a PS mode. In the SBW mode, the control unit separates the steering unit from the operating unit; controls a steer angle of the vehicle in accordance with a manual steering effort; and switches the control mode from the SBW mode to the PS mode when an SBW-to-PS mode switch condition is satisfied, the SBW-to-PS mode switch condition including a condition that the steer angle is larger than or equal to a first threshold angle. In the PS mode, the control unit connects the steering unit and the operating unit; controls an assist steering effort to boost the manual steering effort.