Steer-by-wire steering gear having a hollow shaft motor and a ball screw drive
View Patent ↗A steering gear for a steer-by-wire steering system of a motor vehicle may include a hollow shaft motor with a stator that is fixed to a housing and a rotatably supported rotor that is arranged coaxially with respect to a longitudinal axis. A worm gear may extend through the rotatably supported rotor. The worm gear comprises a spindle nut that is arranged coaxially relative to the longitudinal axis, that is connected in terms of driving to the rotor, and that is located on a spindle that is displaceable by way of the hollow shaft motor along the longitudinal axis. The angle of inclination of the worm gear may be less than 4.5°.
1. A steer-by-wire steering system for a motor vehicle, the steer-by-wire steering system comprising:
a steering gear comprising:
a hollow shaft motor that includes
a stator that is fixed to a housing, and
a rotatably supported rotor that is arranged coaxially with respect to a longitudinal axis; and
a worm gear extending through the rotatably supported rotor, wherein the worm gear comprises a spindle nut that is disposed coaxially relative to the longitudinal axis, that is connected in terms of driving to the rotatably supported rotor, and that is located on a spindle that is displaceable by way of the hollow shaft motor along the longitudinal axis, wherein an angle of inclination of the worm gear is less than 4.5°, the steering gear configured to act on steered wheels;
a control unit;
a feedback actuator configured to be acted upon by a driver according to a driver-desired steering angle via steering input means, wherein the feedback actuator is configured to transmit a feedback signal to the steering input means in response to the driver-desired steering angle and a travel state of the motor vehicle; and
a signal transmission device configured to transmit the driver-desired steering angle to the control unit,
wherein the control unit is configured to control the steering gear to transform the driver-desired steering angle into a redirection of the steered wheels.
2. The steer-by-wire steering system of claim 1 wherein the spindle is configured as a steering rod that is connected to tie rods to steer the steered wheels.
3. The steer-by-wire steering system of claim 1 wherein the angle of inclination of the worm gear is less than 4°.
4. The steer-by-wire steering system of claim 1 wherein the angle of inclination of the worm gear is less than 3.5°.
5. The steer-by-wire steering system of claim 1 wherein the worm gear is a roller member worm gear.
6. The steer-by-wire steering system of claim 1 wherein the worm gear is a ball screw drive.
7. The steer-by-wire steering system of claim 1 wherein the worm gear is a trapezoidal screw drive.
8. The steer-by-wire steering system of claim 1 wherein the worm gear is a roller screw drive.
9. The steer-by-wire steering system of claim 1 wherein the rotor is disposed directly on the spindle nut and is connected thereto in a rotationally secure manner.
10. The steer-by-wire steering system of claim 1 comprising an intermediate gear transmission that reduces a speed of the hollow shaft motor and that connects the rotor to the spindle nut.