Vehicle airbag device and vehicle occupant restraint device

1. A vehicle airbag device comprising:

an airbag receiving gas supplied from an inflator and being adapted to be inflated and deployed in front of an upper body and above thighs of an occupant seated in a vehicle seat;

the airbag including, in the event that the gas has been supplied inside the airbag and the airbag inflates and deploys, an inflation section having an endless annular shape as viewed along a vehicle width direction, and a hollow section formed in a central portion of the inflation section;

the hollow section being in communication with an exterior of the airbag; and

air at the exterior flowing into the hollow section during inflation and deployment.

2. The vehicle airbag device of claim 1 , wherein the airbag is inflated and deployed in a tube shape including an opening at least one end of two vehicle width direction ends of the tube shape.

3. The vehicle airbag device of claim 1 , wherein:

the vehicle seat is a rear seat disposed at a vehicle rear of a front seat, which is another vehicle seat; and

the airbag is adapted to be inflated and deployed between a seatback of the front seat and the upper body of the occupant.

4. The vehicle airbag device of claim 3 , wherein the airbag is configured to be stored in the seatback of the front seat, and is inflated and deployed toward a vehicle rear side on being supplied with the gas.

5. The vehicle airbag device of claim 1 , wherein the airbag is configured to be stored in an armrest or a side door disposed beside the occupant, and is inflated and deployed toward one side in the vehicle width direction on being supplied with the gas.

6. The vehicle airbag device of claim 1 , wherein:

the airbag includes a bag inner regulating member that is provided inside the inflation section, that couples together an outer peripheral portion and an inner peripheral portion at a hollow section side of the endless annular shaped inflation section, and that causes the inflation section to bend at a plurality of locations along a circumferential direction of the inflation section accompanying inflation and deployment of the inflation section.

7. The vehicle airbag device of claim 6 , wherein the bag inner regulating member runs continuously in an endless annular shape around the circumferential direction of the inflation section and includes a plurality of holes arranged in the circumferential direction of the inflation section.

8. The vehicle airbag device of claim 6 , wherein a plurality of the bag inner regulating members are arranged in the vehicle width direction inside the inflation section.

9. The vehicle airbag device of claim 1 , further comprising:

a bag outer regulating member that is provided inside the hollow section, that couples a plurality of locations separated from each other in a circumferential direction at an inner peripheral portion on a hollow section side of the inflation section, and that causes the inflation section to bend at a plurality of locations along the circumferential direction of the inflation section accompanying inflation and deployment of the inflation section.

10. A vehicle occupant restraint device comprising:

a pair of the vehicle airbag devices of claim 1 ;

the airbags in the pair of vehicle airbag devices being inflated and deployed alongside each other in the vehicle width direction; and

one airbag of the airbags being set with a larger vehicle width direction dimension in an inflated and deployed state than the other airbag.