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.

The present embodiments relate to a steer-by-wire type steering apparatus, which prevents a steering shaft from mechanically rotating by means of a gear structure when a driver turns the steering wheel at the maximum rotation angle or greater, so as to enable efficient limiting of the steering wheel operation of the driver to be within a maximum rotation angle without increasing the size, the weight and the like of a motor for transmitting torque to the steering shaft and the like, and to be advantageous with respect to production costs, packaging and the like.

An electric commercial vehicle power steering system includes an input shaft, an electric motor, and a planetary gear set, a drive coupling, and an output shaft. A first one of a sun gear, a planet carrier, and a ring gear of the planetary gear set is connected to and rotatable with a rotor of the electric motor, and a second one of the sun gear, the planet carrier, and the ring gear of the planetary gear set is connected to and rotatable with a first gear of the drive coupling. A second gear of the drive coupling is connected to and rotatable with the input shaft. A globoidal worm drive is arranged between the input shaft and the output shaft. The globoidal worm drive couples the input shaft to the output shaft such that the output shaft is rotatable with the input shaft via the globoidal worm drive.

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.

The present invention provides steer-by-wire steering apparatuses that are capable of generating a counter force for improving steering feel with a simple structure and are particularly suitable for an autonomous vehicle by virtue of a reduced size.

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 reducer of an electric power steering apparatus includes: a worm shaft having a first end thereof supported by a first bearing coupled to a housing and a second end supported by a second bearing coupled to the housing; a damper axially supported on an outer race of the second bearing; and a damper support member having a first side axially supported on the damper and a second side supported on an inner face of the housing. The worm shaft can be assembled with constant rotational torque at an accurate position with respect to the centers of the bearings at the opposite ends. And, the axial and radial movements of the worm shaft can be buffered and the load applied to the worm shaft in the direction in which the worm shaft is engaged with the worm wheel can be reduced.

A method for manufacturing a worm wheel including an inner wheel element including a side plate portion and a tubular eave portion, and an outer wheel element including a wheel tooth portion on an outer circumferential surface thereof, and coupled and fixed to the inner wheel element in a manner of covering a radially outer portion of the side plate portion and the eave portion, the method includes: molding the outer wheel element by disposing a mold around a radially outer portion of the inner wheel element, and feeding the molten synthetic resin from an annular or arc-shaped injection gate toward a pocket portion that is continuous over an entire circumference of a cavity present between an inner surface of the mold and a surface of the inner wheel element and that is present on a radially inner side of the eave portion.

A recirculating ball power steering system includes an electric motor. The system also includes a ball screw rotatably driven by the electric motor. The system further includes a ball nut translatable along the ball screw in a linear direction during rotation of the ball screw. The system yet further includes a sliding joint in sliding contact with an outer surface of the ball nut, the sliding joint moveable in a non-parallel direction relative to the linear direction of the ball nut.

According to embodiments of the present invention, when a driver applies steering torque greater than the reaction torque of a reaction motor to a steering shaft, the steering shaft is mechanically prevented from rotating any more, and thus the driver's steering feel can be improved.