Airbag and airbag module for a motor vehicle having such an airbag
The invention relates to an airbag ( 14 ) for unfolding between a vehicle part ( 10 ) and a vehicle occupant ( 18 ), comprising an impact wall ( 20 ) which, in the installed and unfolded state of the airbag ( 14 ), faces a vehicle occupant ( 18 ) and a circumferential wall ( 22 ) which is connected to the impact wall ( 20 ) and, in the installed and unfolded state of the airbag ( 14 ), extends between the impact wall ( 20 ) and the vehicle part ( 10 ), wherein the circumferential wall ( 22 ) is made with multiple layers, at least in some sections, and forms at least one annular tube ( 23 ) which delimits an annular inflatable first airbag volume (V 1 ), and wherein a radially inner layer ( 26 ) of the circumferential wall ( 22 ), together with the impact wall ( 20 ), delimits an inflatable second airbag volume (V 2 ) that is separate from the first airbag volume (V 1 ). The invention further relates to an airbag module ( 12 ) having such an airbag ( 14 ).
1. An airbag for unfolding between a vehicle part ( 10 ) and a vehicle occupant ( 18 ), comprising
an impact wall ( 20 ) which, in an installed and unfolded state of the airbag ( 14 ), faces the vehicle occupant ( 18 ), and
a circumferential wall ( 22 ) which is connected to the impact wall ( 20 ) and, in the installed and unfolded state of the airbag ( 14 ), extends between the impact wall ( 20 ) and the vehicle part ( 10 ),
wherein the circumferential wall ( 22 ) is made with multiple layers at least in sections and forms at least one annular tube ( 23 ) which delimits an annular inflatable first airbag volume (V 1 ),
wherein a radially inner layer ( 26 ) of the circumferential wall ( 22 ) together with the impact wall ( 20 ) delimits an inflatable second airbag volume (V 2 ) that is separate from the first airbag volume (V 1 ), and
wherein an axial distance (L) between the impact wall ( 20 ) and the vehicle part ( 10 ) is larger when the second airbag volume (V 2 ) is inflated than when the first airbag volume (V 1 ) is inflated.
2. The airbag according to claim 1 , wherein when the first airbag volume (V 1 ) is inflated, the at least one annular tube ( 23 ) has a substantially circular tube cross-section and, when the second airbag volume (V 2 ) is inflated, is subjected to axial tensile load so that the radially inner layer ( 26 ) and a radially outer layer ( 28 ) of the circumferential wall ( 22 ) are adjacent to each other and extend substantially in an axial direction.
3. The airbag according to claim 1 , wherein the second airbag volume (V 2 ) is larger than the first airbag volume (V 1 ).
4. The airbag according to claim 1 , wherein tethers ( 30 ) extend across the second airbag volume (V 2 ) and connect respective opposite sections of the circumferential wall ( 22 ).
5. The airbag according to claim 1 , wherein the circumferential wall ( 22 ) forms plural annular tubes ( 23 ) arranged in series in an axial direction which are in flow communication with one another.
6. The airbag according to claim 1 , wherein seams ( 24 ) suited for subdivision into plural annular tubes ( 23 ) are provided in the circumferential wall ( 22 ).
7. The airbag according to claim 1 , wherein the vehicle part ( 10 ) is a vehicle steering wheel ( 38 ) rotatable about a steering axis (A), wherein the annular tube ( 23 ) in the installed and unfolded state of the airbag ( 14 ) encloses the steering axis (A).
8. An airbag module for a motor vehicle, comprising
an airbag ( 14 ) according to claim 1 ,
a gas generator ( 32 ) for inflating the airbag ( 14 ), and
a control unit ( 36 ) for activating the gas generator ( 32 ),
wherein boundary conditions for applying generator gas to the first airbag volume (V 1 ) or to the second airbag volume (V 2 ) are deposited in the control unit ( 36 ).
9. The airbag module according to claim 8 , wherein the gas generator ( 32 ) is a single-stage design and, upon activation thereof, releases a predetermined amount of gas which can optionally be supplied to the first airbag volume (V 1 ) or to the second airbag volume (V 2 ).
10. The airbag module according to claim 9 , wherein a gas guiding means ( 34 ) is provided which is adjustable via the control unit ( 36 ) so that it supplies released generator gas optionally to the first airbag volume (V 1 ) or to the second airbag volume (V 2 ).
11. An airbag module for a motor vehicle, comprising
an airbag ( 14 ),
a gas generator ( 32 ) for inflating the airbag ( 14 ), and
a control unit ( 36 ) for activating the gas generator ( 32 ),
wherein the airbag comprises:
an impact wall ( 20 ) which, in an installed and unfolded state of the airbag ( 14 ), faces a vehicle occupant ( 18 ), and
a circumferential wall ( 22 ) which is connected to the impact wall ( 20 ) and, in the installed and unfolded state of the airbag ( 14 ), extends between the impact wall ( 20 ) and a vehicle part ( 10 ),
wherein the circumferential wall ( 22 ) is made with multiple layers at least in sections and forms at least one annular tube ( 23 ) which delimits an annular inflatable first airbag volume (V 1 ),
wherein a radially inner layer ( 26 ) of the circumferential wall ( 22 ) together with the impact wall ( 20 ) delimits an inflatable second airbag volume (V 2 ) that is separate from the first airbag volume (V 1 ), and
wherein boundary conditions for applying generator gas to the first airbag volume (V 1 ) or to the second airbag volume (V 2 ) are deposited in the control unit ( 36 ).
12. The airbag module according to claim 11 , wherein when the first airbag volume (V 1 ) is inflated, the at least one annular tube ( 23 ) has a substantially circular tube cross-section and, when the second airbag volume (V 2 ) is inflated, is subjected to axial tensile load so that the radially inner layer ( 26 ) and a radially outer layer ( 28 ) of the circumferential wall ( 22 ) are adjacent to each other and extend substantially in an axial direction.
13. The airbag module according to claim 11 , wherein an axial distance (L) between the impact wall ( 20 ) and the vehicle part ( 10 ) is larger when the second airbag volume (V 2 ) is inflated than when the first airbag volume (V 1 ) is inflated.
14. The airbag module according to claim 11 , wherein the second airbag volume (V 2 ) is larger than the first airbag volume (V 1 ).
15. The airbag module according to claim 11 , wherein tethers ( 30 ) extend across the second airbag volume (V 2 ) and connect respective opposite sections of the circumferential wall ( 22 ).
16. The airbag module according to claim 11 , wherein the circumferential wall ( 22 ) forms plural annular tubes ( 23 ) arranged in series in an axial direction which are in flow communication with one another.
17. The airbag module according to claim 11 , wherein seams ( 24 ) suited for subdivision into plural annular tubes ( 23 ) are provided in the circumferential wall ( 22 ).
18. The airbag module according to claim 11 , wherein the vehicle part ( 10 ) is a vehicle steering wheel ( 38 ) rotatable about a steering axis (A), wherein the annular tube ( 23 ) in the installed and unfolded state of the airbag ( 14 ) encloses the steering axis (A).
19. The airbag module according to claim 11 , wherein the gas generator ( 32 ) is a single-stage design and, upon activation thereof, releases a predetermined amount of gas which can optionally be supplied to the first airbag volume (V 1 ) or to the second airbag volume (V 2 ).
20. The airbag module according to claim 19 , wherein a gas guiding means ( 34 ) is provided which is adjustable via the control unit ( 36 ) so that it supplies released generator gas optionally to the first airbag volume (V 1 ) or to the second airbag volume (V 2 ).