A ball screw device includes a screw shaft having a first screw groove formed on an outer circumference thereof, a ball screw nut having a second screw groove formed on an inner circumference thereof, and a plurality of balls disposed in a spiral ball raceway wherein the first screw groove and the second screw groove face each other. A circulation member is attached to an attachment hole radially penetrating the ball screw nut and a circulation path is formed, the circulation path allowing endless circulation of each of the balls rolling in the ball raceway by short-circuiting between two points of the ball raceway.

Provided is a motor-driven power steering system including: a motor driver; and a controller, wherein the controller is configured to: receive a first rotation angle obtained by a steering wheel angle sensor according to steering and a second rotation angle obtained by a motor position sensor, when a steered position of the steering wheel is in an auxiliary steering limit section and a difference value between the first rotation angle and the second rotation angle is different from a predetermined reference value, change a rotation position of the steering wheel angle sensor and a rotation position of the motor position sensor to an initial original position, when changed to the initial original position, receive the first rotation angle and the second rotation angle again, and control the motor driver to perform auxiliary steering based on the first rotation angle and the second rotation angle received again.

Power assisted steering systems provide a gear reduction of approximately 25:1 between a steering wheel and a steering mechanism and approximately 625:1 between an electric motor and a steering mechanism. The system is back-driveable from the steering mechanism. In one embodiment, the gear reduction is provided primarily by three planetary gear sets, with the remainder provided by axis transfer gearing. In another embodiment, the gear reduction is provided primarily by a cycloidal gear set, with the remainder provided by axis transfer gearing.

A steering system (10) for a motor vehicle, which steering system (10) is configured as a steer-by-wire steering system, comprises a rack (14), an electric drive (16) for the longitudinal displacement of the rack (14), and a rotatably mounted supporting element (20) which is spaced apart from the electric drive (16) along the longitudinal axis of the rack (14), and the rotatably mounted supporting element (20) being in toothed engagement with the rack (14).

In a controller for a steering device, the steering device includes a structure where motive power transmission between a steering unit and a turning unit is separated. The controller includes a control circuit configured to control operation of a steering-side motor that is provided in the steering unit to give steering reaction force that is force against the steering input into the steering unit. In a case where turning of the turning wheels to one direction is restricted, the control circuit is configured to calculate restriction reaction force for restricting steering that is to turn the turning wheels to the one direction. The control circuit is configured to calculate the restriction reaction force based on information on the steering unit.

A steering system for a vehicle according to an example in the present disclosure includes a steering mechanism that is mechanically disconnected from a steering wheel to cause a driving wheel to be turned by a turning motor, and a control device that provides a motor command value to the turning motor. The control device has a two-degree-of-freedom control system including a feed-forward model for converting a target turning angle into a feed-forward value of the motor command value, and a feedback model for converting a difference between the target turning angle and an actual turning angle into a feedback value of the motor command value. A transfer function describing the feed-forward model contains a variable coefficient. The control device changes the variable coefficient of the transfer function based on information about road surface reaction.

An electrically operated steering system (1) is provided for a vehicle (2) with a rack (3) for attaching the steering system (1) to a frame of the vehicle (2), two steerable wheels (4) that are pivotably attached to the rack (3), a rod element (5) arranged on the rack (3), which is slidable in its longitudinal direction in relation to the rack (3), a kinematic unit (13), which is coupled to the rod element (5) and which transforms a movement of the rod element (5) into a steering rotation of the wheels (4), an electric machine (6), which is mechanically connected to the rod element (5) for effecting the movement of the rod element (5), and a lateral force absorbing mechanism (7), which is configured for absorbing a lateral force produced by the kinematic unit (13) in relation to the rod element (5).

An electric power steering apparatus according to the present embodiments comprises an input shaft connected to an steering shaft, a first output shaft coupled to the input shaft, a first gear provided at one end of the first output shaft, a second gear meshed with the first gear, a second output shaft provided with the second gear at one end and having an outer screw groove formed on an outer circumferential surface of a position spaced apart from the second gear in an axial direction and rotating in conjunction with the second gear, and a sliding member having an inner screw groove corresponding to the outer screw groove formed on an inner circumferential surface thereof, coupled to the second output shaft via a ball, and sliding in an axial direction to operate a link connected to vehicle wheels.

A method is for operating a steering system, more particularly a steer-by-wire steering system. The steering system includes at least one wheel steering angle control element which is provided to influence and/or change a wheel steering angle of at least one vehicle wheel depending on a target specification signal correlated with a steering specification. The wheel steering angle control element has a limited maximum wheel steering angle control range for changing the wheel steering angle, and the target specification signal is limited by a saturation to the maximum wheel steering angle control range. The target specification signal is modified in such a manner that the, more particularly modified, target specification signal has a constant and differentiable curve at least in an edge range of the wheel steering angle control range.

An electrically driven rack and pinion steering system of a motor vehicle has an axially displaceably mounted rack which transmits a steering movement for steered wheels of the motor vehicle, has an electric drive which provides a steering force and interacts with the rack, and has a housing which receives the rack and a drive element of the drive. The drive element is in engagement with a toothing system of the rack. A bearing assembly is arranged on a section of the rack without a toothing system axially on each side of the drive element, with a carrier cylinder, on the outer shell face of which an outer contact seal is arranged and on the inner shell face of which an inner contact seal is arranged, the contact seals sealing the housing with respect to the rack.