Steering column for a steer-by-wire steering device

1. An adjustable steering column for a steer-by-wire steering device of a motor vehicle, the adjustable steering column comprising:

an actuating unit that is mounted rotatably about a longitudinal axis;

a first casing tube in which a second casing tube is disposed in a rotationally fixed manner with respect to the longitudinal axis and is mounted so as to be movable axially in a telescopic manner; and

a steering spindle that is disposed within and rotatable relative to the second casing tube; and

an actuating drive configured to move the second casing tube axially in and out relative to the first casing tube, the actuating drive comprising a spindle drive with a threaded spindle that

is disposed parallel to the longitudinal axis,

is configured to be driven rotatably by an electric servomotor,

is supported on the first casing tube and extends within the first casing tube, and

is screwed into a spindle nut that is attached in a rotationally fixed manner to the second casing tube.

2. The adjustable steering column of claim 1 wherein a cover in which the threaded spindle is rotatably mounted is disposed on a front end of the first casing tube facing away from the second casing tube.

3. The adjustable steering column of claim 1 wherein the actuating drive is disposed at a front end of the first casing tube facing away from the second casing tube.

4. The adjustable steering column of claim 1 comprising a third casing tube that is mounted so as to be rotatably fixed and axially movable in a telescopic manner in the second casing tube, the third casing tube being connected to the actuating drive and being movable in and out axially relative to the second casing tube.

5. The adjustable steering column of claim 4 comprising a threaded bolt that is attached in a rotationally fixed manner to the third casing tube and is screwed into an axial threaded borehole in the threaded spindle.

6. The adjustable steering column of claim 5 wherein threads of the threaded bolt and threads of the threaded spindle have different thread pitches.

7. The adjustable steering column of claim 5 wherein when a limiting force is exceeded, at least one of the spindle nut or the threaded bolt is movable in an axial direction relative to at least one of the second casing tube or the third casing tube, accompanied by a conversion of energy.

8. The adjustable steering column of claim 1 comprising an actuator disposed in the casing unit, wherein the actuator interacts with the steering spindle and applies a torque to the steering spindle.

9. The adjustable steering column of claim 1 comprising at least one of a rotational angle sensor or a torque sensor disposed in the casing unit.

10. The adjustable steering column of claim 1 comprising a worm gear system disposed between the electric servomotor and the threaded spindle.

11. The adjustable steering column of claim 1 comprising a supporting unit that secures the casing unit, wherein the supporting unit is connectable to a body of the motor vehicle.

12. An adjustable steering column for a steer-by-wire steering device of a motor vehicle, the adjustable steering column comprising:

a casing unit that includes a first casing tube in which a second casing tube is disposed in a rotationally fixed manner with respect to a longitudinal axis and is mounted so as to be movable axially in a telescopic manner;

a steering spindle that is disposed within and rotatable relative to the second casing tube; and

an actuating drive configured to move the second casing tube axially relative to the first casing tube, the actuating drive comprising a spindle drive with a threaded spindle that

is disposed parallel to the longitudinal axis,

is supported on the first casing tube and extends within the first casing tube, and

is screwed into a spindle nut that is attached in a rotationally fixed manner to the second casing tube.

13. The adjustable steering column of claim 12 wherein a cover in which the threaded spindle is rotatably mounted is disposed on a front end of the first casing tube facing away from the second casing tube.

14. The adjustable steering column of claim 12 wherein the actuating drive is disposed at a front end of the first casing tube facing away from the second casing tube.

15. The adjustable steering column of claim 12 comprising a third casing tube that is mounted so as to be rotatably fixed and axially movable in a telescopic manner in the second casing tube, the third casing tube being connected to the actuating drive and being movable in and out axially relative to the second casing tube.

16. The adjustable steering column of claim 15 comprising a threaded bolt that is attached in a rotationally fixed manner to the third casing tube and is screwed into an axial threaded borehole in the threaded spindle.

17. The adjustable steering column of claim 16 wherein threads of the threaded bolt and threads of the threaded spindle have different thread pitches.

18. The adjustable steering column of claim 16 wherein when a limiting force is exceeded, at least one of the spindle nut or the threaded bolt is movable in an axial direction relative to at least one of the second casing tube or the third casing tube.

19. The adjustable steering column of claim 12 comprising an actuator disposed in the casing unit, wherein the actuator interacts with and applies a torque to the steering spindle.

20. The adjustable steering column of claim 12 comprising at least one of a rotational angle sensor or a torque sensor disposed in the casing unit.