Airbag including hub and inflatable fins

1. An airbag comprising:

a hub defining an inflation chamber and being inflatable to an inflated position; and

inflatable fins connected to the hub and spaced from each other around a circumference of the hub;

each of the inflatable fins extending radially from the hub in the inflated position;

the hub is elongated along a longitudinal axis and each inflatable fin is elongated along an axis in parallel with the longitudinal axis; and

the hub includes a top and a bottom spaced from each other along the longitudinal axis, and the inflatable fins are spaced from the top and the bottom.

2. The airbag of claim 1 , wherein the hub includes panels spaced from each other around the circumference of the hub in alternating arrangement with the inflatable fins.

3. The airbag of claim 2 , wherein the panels are arranged in a cylindrical pattern in the inflated position.

4. The airbag of claim 1 , wherein the inflatable fins extend away from the inflation chamber in the inflated position.

5. The airbag of claim 1 , wherein the inflatable fins are in fluid communication with the inflation chamber.

6. The airbag of claim 1 , wherein the hub includes openings extending between the inflation chamber and the inflatable fins.

7. The airbag of claim 6 , wherein each inflatable fin includes a first side and a second side opposing the first side about the opening, and a tether attached to the first side and to the second side.

8. The airbag of claim 6 , further comprising a tether having a first end connected to the hub and a second end connected to the hub and extending across the opening.

9. The airbag of claim 1 , wherein each inflatable fin is spaced equidistantly from adjacent inflatable fins.

10. The airbag of claim 1 , wherein a first tether is attached to a first inflatable fin and a second inflatable fin external to the inflation chamber, a second tether is attached to the second inflatable fin and a third inflatable fin external to the inflation chamber, a third tether is attached to the third inflatable fin and a fourth inflatable fin external to the inflation chamber, and a fourth tether is attached to the fourth inflatable fin and the first inflatable fin external to the inflation chamber.

11. The airbag of claim 1 , wherein the hub is cylindrical.

12. An occupant restraint system comprising:

a roof;

an airbag supported by the roof, the airbag including a hub defining an inflation chamber and being inflatable to an inflated position, the hub in the inflated position being cylindrical having a top and a bottom and being elongated along a longitudinal axis that extends through the top, the bottom, and the roof; and

inflatable fins connected to the hub and spaced from each other around a circumference of the hub;

each of the inflatable fins in the inflated position extending radially from the hub and being elongated along an axis in parallel with the longitudinal axis.

13. The occupant restraint system of claim 12 , wherein the hub includes panels spaced from each other around the circumference of the hub in alternating arrangement with the inflatable fins.

14. The occupant restraint system of claim 13 , wherein the panels are arranged in a cylindrical pattern in the inflated position.

15. The occupant restraint system of claim 12 , wherein the inflatable fins extend away from the inflation chamber in the inflated position.

16. The occupant restraint system of claim 12 , wherein the inflatable fins are in fluid communication with the inflation chamber.

17. The occupant restraint system of claim 16 , wherein the hub includes openings extending between the inflation chamber and each of the inflatable fins.

18. The occupant restraint system of claim 12 , wherein a first tether is attached to a first inflatable fin and a second inflatable fin external to the inflation chamber, a second tether is attached to the second inflatable fin and a third inflatable fin external to the inflation chamber, a third tether is attached to the third inflatable fin and a fourth inflatable fin external to the inflation chamber, and a fourth tether is attached to the fourth inflatable fin and the first inflatable fin external to the inflation chamber.

19. The occupant restraint system of claim 12 , wherein the longitudinal axis is perpendicular to the roof.

20. An airbag comprising:

a hub defining an inflation chamber and being inflatable to an inflated position;

inflatable fins connected to the hub and spaced from each other around a circumference of the hub;

each of the inflatable fins extending radially from the hub in the inflated position;

the hub includes openings extending between the inflation chamber and the inflatable fins; and

a tether having a first end connected to the hub and a second end connected to the hub and extending across the opening.