Airbag for a vehicle occupant restraint system of a motor vehicle

1. A gas bag for a vehicle occupant restraint system of a motor vehicle, comprising

at least one first inflatable chamber configured for the protection of the head of a vehicle occupant;

at least one second inflatable chamber configured for the protection of a shoulder and a thorax region of the vehicle occupant,

wherein the gas bag is to be arranged in or on a side of a vehicle seat facing the vehicle interior space, and

wherein in the inflated condition of the gas bag the first and the second chamber are rotatable relative to each other;

a connecting portion via which the first and the second chamber are in flow connection with each other during the inflation of the gas bag,

wherein the first chamber is separated from the second chamber by a cutout located in front of the connecting portion, and

at least one fastening element via which the first chamber is attached to another portion of the gas bag or is attachable to a vehicle part different from the gas bag in such a way that the first chamber is held in position in the event of an impact of the vehicle occupant on the second chamber, while as a result of the impact the second chamber turns away from the first chamber.

2. The gas bag according to claim 1 , wherein the first chamber is attached to the other portion of the gas bag or to the vehicle part different from the gas bag via the at least one fastening element.

3. The gas bag according to claim 1 , wherein the two chambers are rotatable against each other by twisting the connecting portion.

4. The gas bag according to claim 3 , wherein the two chambers are rotatable against each other about an axis of rotation specified by the connecting portion, in particular at least approximately parallel to the connecting portion.

5. The gas bag according to claim 3 , wherein the cutout extends from a front side of the gas bag up to the connecting portion or up to a structure defining the connecting portion.

6. The gas bag according to claim 5 , wherein the first and the second chamber are connected to each other across the cutout by means of a connecting element, in particular in the form of a strap or a sail.

7. The gas bag according to claim 1 , wherein the second chamber comprises a middle portion at least sectionally defined by a seam, wherein a front portion of the first chamber is connected to a region of a circumference of the middle portion.

8. The gas bag according to claim 7 , wherein a front portion of the first chamber is connected to an inflatable region of the second chamber surrounding the middle portion.

9. A vehicle seat with a gas bag according to claim 1 .

10. The gas bag according to claim 1 , wherein the second chamber comprises a middle portion at least sectionally defined by a seam, wherein a front portion of the first chamber is connected to an inflatable region of the second chamber surrounding the middle portion.

11. The gas bag according to claim 1 , wherein the at least one first inflatable chamber is located above the at least one second inflatable chamber.

12. A gas bag for a vehicle occupant restraint system of a motor vehicle, comprising

at least one first inflatable chamber configured for the protection of the head of a vehicle occupant;

at least one second inflatable chamber configured for the protection of a thorax region of the vehicle occupant,

wherein the gas bag is to be arranged in or on a side of a vehicle seat facing the vehicle interior space, and

wherein the gas bag is configured such that during the inflation of the gas bag the first chamber moves relative to the second chamber towards a vehicle occupant sitting on the vehicle seat;

a connecting portion via which the first and the second chamber are in flow connection with each other during the inflation of the gas bag,

wherein the first chamber is separated from the second chamber by a cutout located in front of the connecting portion, and

at least one connecting element that couples the first and the second chamber to each other or via which the first chamber is connectable to a vehicle part different from the gas bag in such a way that the connecting element supports the movement of the first chamber relative to the second chamber.

13. The gas bag according to claim 12 , wherein in the inflated condition of the gas bag and as seen in transverse vehicle direction the first chamber at least partly extends further across the vehicle seat than the second chamber.

14. The gas bag according to claim 12 , wherein in the inflated condition of the gas bag the first chamber at least partly extends in front of the vehicle occupant.

15. The gas bag according to claim 12 , wherein during the inflation of the gas bag the first chamber performs a rotary movement relative to the second chamber towards the vehicle occupant.

16. The gas bag according to claim 12 , further comprising the connecting portion via which the first and the second chamber are in flow connection with each other during the inflation of the gas bag, wherein a partial section of the first chamber located before the connecting portion as seen in the direction of forward travel is fixed to the second chamber.

17. The gas bag according to claim 12 , wherein the movement of the first chamber relative to the second chamber is supported by the shape of the gas bag.

18. The gas bag according to claim 12 , wherein the at least one first inflatable chamber is located above the at least one second inflatable chamber.