A steering device includes: a rack shaft; a rack housing; a pinion shaft that meshes with the rack shaft; a speed reducer having a worm wheel that is coupled to the pinion shaft and a worm shaft that meshes with the worm wheel; a speed reducer housing; a motor that drives the worm shaft; a plate-shaped cover that seals an opening of the speed reducer housing; and a breather valve that is mounted on the cover in a state of penetrating through the cover. An inner surface of the cover that faces the worm wheel has an entry restricting part that restricts entry of a lubricant into the breather valve.

The present invention relates to a steer-by-wire system for a vehicle, and the system may include a reaction motor generating reaction torque based on the turning of a steering wheel, a steering motor implementing a steering manipulation, a motor location detector measuring a current steering angle by detecting a rotation location of the steering motor, a location controller calculating a target steering angle by applying the amount of a location control error to a vehicle speed, command steering angle and current steering angle, a steering controller driving the steering motor based on the target steering angle, and a reaction controller generating the reaction torque according to a driver's steering state based on the vehicle speed and a steering angular velocity, compensating for the reaction torque based on the amount of the location control error, and driving the reaction motor based on the final reaction torque.

An apparatus for use in turning at least one steerable vehicle wheel includes a steering member rotatably supported in a housing. The steering member rotates relative to the housing about a first axis to effect turning movement of the at least one steerable vehicle wheel. A ball nut is connected with an externally threaded portion of the steering member. The steering member is rotatable relative to the ball nut assembly to axially move the ball nut assembly relative to the housing. An electric motor is operable to apply a rotational force to the steering member to urge the steering member to rotate relative to the housing. The electric motor has an output shaft extending along a second axis extending generally parallel to the first axis. A first gear is rotatable about the second axis with the output shaft of the motor. A second gear in meshing engagement with the first gear is rotatable about a third axis extending transverse to the second axis. A third gear is rotatable with the second gear about the third axis. A fourth gear in meshing engagement with the third gear is rotatable with the steering member relative to the housing.

A steering system includes a first wheel and a second wheel laterally spaced apart from the first wheel, and a third wheel and a fourth wheel laterally spaced apart from the third wheel. The first wheel is rotatably coupled to a first knuckle and the second wheel is rotatably coupled to a second knuckle. The third wheel and the fourth wheel are both pivotally fixed in a forward-aligned orientation. The steering system includes a first tie rod having a first end pivotally coupled to the first knuckle and a second end pivotally coupled to a mechanical linkage, a second tie rod having a first end pivotally coupled to the second knuckle and a second end pivotally coupled to the mechanical linkage, and an electrical actuator coupled to the mechanical linkage. The mechanical linkage is arranged in front of the electrical actuator relative to a travel direction.

A steering control device that can more appropriately transmit a road-surface reaction force to a steering wheel is provided. The steering control device feedback controls a steering angle to a target steering angle that is a target value of the steering angle. The steering control device includes an estimated axial force computation circuit that computes an estimated axial force so as to reflect a road-surface reaction force in a reaction force generated by a reaction force actuator. The estimated axial force computation circuit computes the estimated axial force by causing a friction compensation amount computation circuit and an efficiency compensation gain computation circuit to compensate an initial estimated axial force computed by an initial estimated axial force computation circuit.

A control device that controls a control target including at least a motor in a steering mechanism including an input shaft to which a steering wheel is connected, an output shaft connected to the input shaft via a torsion bar, and the motor connected to the output shaft. The control device includes a reaction force controller to generate an input torque input to the control target based on a torsion bar torque generated in the torsion bar and to control a reaction force transmitted from the steering wheel to the steering person, and an assist controller to generate a correction torque to correct the input torque based on an output of the control target and a nominal model. The assist controller is configured or programmed such that a transfer function of the control target is constrained by a transfer function of the nominal model in a frequency band.

An apparatus for use in turning steerable vehicle wheels includes a rotatable output shaft. A first rotational input assembly is provided for transmitting a steering command from a steering control member to the output shaft. A power transmitting mechanism is configured to transmit the rotational force from the input assembly to the output shaft. The power transmitting mechanism includes a plurality of sector gears. A ball screw has longitudinally separated first and second ball screw ends. A ball nut has a plurality of rack gears. Rotational force from the input assembly turns the ball screw, and the ball nut reciprocates within the housing responsive to rotation of the ball screw to move each of the plurality of rack gears in a longitudinal direction. Longitudinal motion of the rack gear teeth responsively drives the sector gear teeth to transmit the steering command to the output shaft.

There is provided a steering control device that can control even when a systematic error has occurred. An update amount calculation processing circuit manipulates a control angle in accordance with an update amount in order to control steering torque, which is obtained by subjecting the magnitude of steering torque to a decrease correction by a threshold, to target torque through feedback control. The control angle is used to convert a current command value to a value in a fixed coordinate system or the like. The update amount is subjected to a guarding process in accordance with the steering torque by a torque-based guarding processing circuit, and determined as a final update amount for the control angle. The torque-based guarding processing circuit performs the guarding process on the update amount such that the update amount is in an allowable range that matches the steering torque.

A steering device includes a steering rod that includes two ball screw parts, the steering rod being configured to steer a steerable wheel by moving linearly, two ball nuts respectively fastened to the two ball screw parts, two motors each configured to generate a drive force, two transmission mechanisms each including a toothed belt, the two transmission mechanisms being configured to transmit the drive force of each one of the two motors to a corresponding one of the ball nuts, two detectors configured to respectively detect rotation angles of the two motors, and a controller configured to control each of the two motors. The controller is configured to detect tooth jumping of the belts using the rotation angles of the two motors that are detected by the two detectors.

A steering control device includes an electronic control unit. The electronic control unit detects an absolute steering angle. The electronic control unit controls driving of a motor. The electronic control unit determines whether movement of a turning shaft to one of right and left sides has been limited by an end contact or execution of end contact relaxation control. The electronic control unit acquires a plurality of limit position determination angles corresponding to the absolute steering angle. The electronic control unit permits update of an end-position-corresponding angle. The electronic control unit updates the end-position-corresponding angle stored in the electronic control unit.