A steering apparatus includes first and second electric motors that rotate a steering shaft via speed reduction mechanisms, and the motors being disposed to face each other. The first electric motor, a first motor pulley, a second motor pulley and the second electric motor are arranged in order in a rotation axis direction. When a first system electric actuator (including a first nut and the first electric motor) and a second system electric actuator (including a second nut and the second electric motor) are provided to the common steering shaft, in a first axis direction, the first and second nuts can be arranged close to each other, reducing sizes of the peripheries of the nuts.

A ball screw device includes a plurality of ball screw devices. In one ball screw device, a recirculation member is larger than the recirculation member in another ball screw device in terms of one mounting dimension of two mounting dimensions selected from a circumferential length of a part at a side of a pick-up opening portion in each pick-up portion, a circumferential length of a part at a side opposite to the pick-up opening portion in each pick-up portion, a circumferential length of a connection passage portion and an axial length of the connection passage portion, and the recirculation member is smaller than the recirculation member in the other ball screw device in terms of another mounting dimension of the two mounting dimensions, the other ball screw device being different in a diameter of a screw shaft from the one ball screw device.

According to the embodiments, it is possible to mitigate noise by compensating for the clearance inside the bearing supporting the rotation of the ball nut and the clearance between the ball nut and the ball screw and prevent excessive friction between the ball nut and the ball screw and inside the bearing to thereby allow the driver a better steering feel.

An electric motor is controlled so as to suppress movement of a steering mechanism in response to a reverse input from a road surface during travel on rough roads, for example, a gravel road or an unpaved road.

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.

A steering actuator for rear axle steering of a motor vehicle has a spindle drive (5) which comprises pushrods (9) which are connected to a threaded spindle (16) and which are mounted in a housing (6) by means of plain bearings (18), allowing the passage of air, and are connected at each end thereof to an attachment element (12) provided for coupling to a chassis suspension arm, wherein a gaiter (19, 20) is connected on the one side to the housing (6) and on the other side to one of the attachment elements (12) in each case. Each plain bearing (18) is designed as a bearing allowing one revolution of the threaded spindle (16), wherein at least one longitudinal groove (21) abuts one guide bush (23) of the plain bearing (18).

Rotary assist apparatus for recirculating ball steering gears are disclosed. An example motor vehicle steering system includes an input shaft to couple to a steering shaft of a motor vehicle, a worm gear, a first end of the worm gear coupled to the input shaft, a second end of the worm gear fixed to a helical spur gear, a ball nut surrounding a portion of the worm gear, the ball nut including ball bearings and ball guides, an intermediate gear fixed to a first pinion, the first pinion engaged with the helical spur gear, a motor fixed to a second pinion, the second pinion engaged with the intermediate gear, the motor to rotate the worm gear to translate the ball nut, and a sector gear engaged with the ball nut, the sector gear to rotate as the ball nut translates.

A steering actuator comprising a shaft having an input coaxial with an output, wherein the output is in drivable communication with one or more wheels of a vehicle, and a locking mechanism configured to enable the shaft to rotate in both a first direction and a second direction in response to torque provided at the input, and prevent the shaft from rotating in both the first direction and the second direction in response to torque provided at the output.

A power assisted steering system may include a threaded spindle that engages in a spindle nut, extends in a direction of a spindle axis, and is axially displaceable in a housing; and a drive unit having a gearwheel that is connected to the spindle nut in a rotationally fixed manner, can be driven rotatably about the spindle axis, and is rotatably mounted in the housing in a bearing arrangement. The bearing arrangement may have at least one bearing outer ring that is axially supported on the housing at an end face via a spring element, that is received coaxially in a sleeve element, and that is held radially in the housing. The spring element may be formed as a spring portion, and the sleeve element may be formed as a sleeve portion that is connected in one piece to the spring portion, on a one-piece carrier sleeve.

Embodiments of the present invention relate to a rack-driven electric power assisted steering device. Embodiments of the present invention provide a rack-driven electric power assisted steering device comprising: a rack bar which slides in the axial direction in a rack housing and has an outer circumferential screw groove formed at the outer circumferential surface thereof; a ball nut which has an inner circumferential screw groove formed at the inner circumferential surface thereof and corresponding to the outer circumferential screw groove of the rack bar, and has a ball circulation passage formed between the inner and outer circumferential surfaces thereof, the ball circulation passage passing through the ball nut in the axial direction; end caps coupled to one end and the other end of the ball circulation passage, respectively, each of the end caps having a ball return hole provided to circulate balls through the ball circulation passage, the outer circumferential screw groove, and the inner circumferential screw groove; and a support member coupled to the inner circumferential surface of the ball nut while supporting the end caps in the axial direction.