Vehicle seat assembly with a stationary base rail and a seat rail which can be moved relative thereto and with a drive device which is arranged on the base rail

1. A vehicle seat assembly comprising:

a seat frame;

at least one pair of rails including a seat rail, connected to the seat frame, and a base rail configured to be connected to a vehicle floor, wherein the seat rail is configured to be guided by the base rail so that the seat rail is displaceable along a longitudinal direction; and

a drive device configured to adjust the seat rail along the longitudinal direction with respect to the base rail, wherein the drive device includes

a spindle,

a spindle nut that, by way of a thread engagement, is mounted to be rotatable on the spindle,

a gearbox unit operatively connected to the spindle nut and including at least two spur gears each rotatable about rotation axes extending so as to be mutually parallel and aligned along the longitudinal direction, wherein the at least two spur gears include helical teeth, and

an electric motor configured to drive the spindle nut via the gearbox unit,

wherein the spindle is disposed on the seat rail, and the spindle nut and the gearbox unit are disposed on the base rail.

2. The vehicle seat assembly of claim 1 , wherein the vehicle seat assembly includes a first pair of rails and a second pair of rails, wherein the drive device is coupled to the first pair of rails and another drive device is coupled to the second pair of rails.

3. The vehicle seat assembly of claim 1 , wherein the gearbox unit includes a gearbox housing fixedly connected to the base rail.

4. The vehicle seat assembly of claim 3 , wherein the spindle nut is mounted in the gearbox housing, wherein the gearbox housing is configured to engage an anti-rotation safeguard to stop the gearbox housing from rotating with respect the base rail.

5. The vehicle seat assembly of claim 3 , wherein the gearbox housing protrudes through an opening formed by the base rail.

6. The vehicle seat assembly of claim 5 , further comprising a holding angle bracket extending through the opening, wherein the holding angle bracket connects the gearbox housing that engages to the base rail.

7. The vehicle seat assembly of claim 5 , wherein the opening is formed by a base of the base rail, wherein the base faces away from the seat rail.

8. The vehicle seat assembly of claim 7 , wherein the electric motor of the drive device is disposed on a side of the base of the base rail.

9. The vehicle seat assembly of claim 6 , wherein the holding angle bracket at least partially encompasses the gearbox housing.

10. The vehicle seat assembly of claim 6 , wherein the gearbox housing includes a first side and a second side, aligned with the first side with respect to the longitudinal direction, wherein the first side and the second side are each supported by the holding angle bracket.

11. The vehicle seat assembly of claim 1 , wherein the gearbox unit has at least two gear ranges.

12. The vehicle seat assembly of claim 1 , wherein the spindle nut includes an external toothing configured to mesh with a first spur gear of the at least two spur gears such that the spindle nut rotates as the first spur gear rotates.

13. The vehicle seat assembly of claim 12 , wherein engagement between threads of the spindle nut and threads of the spindle are configured to create a self-locking condition.

14. A vehicle seat assembly comprising:

a seat frame;

at least one pair of rails including a seat rail, connected to the seat frame, and a base rail configured to be connected to a vehicle floor, wherein the seat rail is configured to be guided by the base rail so that the seat rail is displaceable along a longitudinal direction; and

a drive device configured to adjust the seat rail along the longitudinal direction with respect to the base rail, wherein the drive device includes

a spindle,

a rotatable spindle nut that, by way of a thread engagement, is mounted to be rotatable on the spindle,

a gearbox unit operatively connected to the spindle nut, and

an electric motor including a drive shaft extending along the longitudinal direction and configured to rotate about the longitudinal direction to drive the spindle nut via the gearbox unit,

wherein the spindle is disposed on the seat rail, and the spindle nut and the gearbox unit are disposed on the base rail.

15. The vehicle seat assembly of claim 14 , wherein the drive shaft of the electric motor supports a first spur gear, wherein the first spur gear engages and meshes with a second spur gear.

16. The vehicle seat assembly of claim 15 , wherein the second spur gear is connected to a third spur gear axially offset from the second spur gear and conjointly rotates in a rotational direction of the second spur gear.

17. The vehicle seat assembly of claim 16 , wherein the third spur gear engages and meshes with a fourth spur gear.

18. The vehicle seat assembly of claim 17 , wherein the fourth spur gear engages and meshes with the spindle nut.