Airbag device

1. An airbag device adapted to be installed in a vehicle for restraint of an occupant and which includes a bag-like cushion that inflates and deploys in front of a seat, the cushion comprising:

an inner inflating section which convexly inflates toward the rear of the vehicle and is adapted to restrain the head of the occupant;

at least one protrusion which is provided to a side of the inner inflating section in a vehicle width direction and which is capable of inflating so as to protrude further toward the rear of the vehicle than the inner inflating section; and

at least one outer inflating section which is provided between the inner inflating section and the protrusion and which convexly inflates toward the rear of the vehicle within a smaller range in the vehicle width direction than an expansion range of the inner inflating section and an expansion range of the protrusion, wherein

a curvature radius of the outer inflating section when inflating is smaller than a curvature radius of the inner inflating section and a curvature radius of the protrusion such that, upon a restraint of the occupant, the outer inflating section is squashed by the inner inflating section and the protrusion, and the protrusion is adapted to being pulled toward a side of the inner inflating section.

2. An airbag device adapted to be installed in a vehicle for restraint of an occupant and which includes a bag-like cushion that inflates and deploys in front of a seat, the cushion comprising:

an inner inflating section which convexly inflates toward the rear of the vehicle and is adapted to restrain the head of the occupant;

at least one protrusion which is provided to a side of the inner inflating section in a vehicle width direction and which is capable of inflating so as to protrude toward the rear of the vehicle; and

at least one outer inflating section which is provided between the inner inflating section and the protrusion and which convexly inflates toward the rear of the vehicle within a smaller range in the vehicle width direction than an expansion range of the inner inflating section in the vehicle width direction and an expansion range of the protrusion in the vehicle width direction,

wherein a curvature radius of the outer inflating section when inflating is smaller than a curvature radius of the inner inflating section and a curvature radius of the protrusion.

3. The airbag device according to claim 2 further comprising, the at least one protrusion is capable of inflating so as to protrude further toward the rear of the vehicle than a protruding amount of the inner inflating section.

4. The airbag device according to claim 2 further comprising, the at least one protrusion is capable of inflating so as to protrude toward the rear of the vehicle by an amount comparable to a protruding amount of the inner inflating section.

5. The airbag device according to claim 2 further comprising, the at least one outer inflating section convexly inflates toward the rear of the vehicle within a smaller range in a vehicle width direction than an expansion range in the vehicle width direction of the inner inflating section and an expansion range in the vehicle width direction of the protrusion.

6. The airbag device according to claim 2 further comprising, in a restraint event the outer inflating section is adapted to be squashed by the inner inflating section and the protrusion, and the protrusion is adapted to being pulled toward a side of the inner inflating section.

7. The airbag device according to claim 2 further comprising, the protrusion is provided to both sides of a forward restraining section in the vehicle width direction and the inner and outer inflating sections form at least a part of the forward restraining section.

8. The airbag device according to claim 2 further comprising,

at least one inner tether having one end connected to a first portion constituting a boundary between the inner inflating section and the outer inflating section inside the cushion, and which is tensioned during an inflation so as to pull the first portion in a direction toward the front of the vehicle; and

at least one outer tether having one end connected to a second portion constituting a boundary between the outer inflating section and the protrusion inside the cushion, and which is tensioned during the inflation so as to pull the second portion in a direction toward the front of the vehicle.

9. The airbag device according to claim 8 further comprising,

the outer inflating section is provided on both sides of the inner inflating section in the vehicle width direction, and

the inner tether and the outer tether are provided singly on each of a left and a right sides in the vehicle width direction.

10. The airbag device according to claim 8 further comprising, at least one of the one end of the outer tether and the one end of the inner tether each have a vertical dimension sufficient to cover a vertical range of the protrusion.

11. The airbag device according to claim 8 further comprising, other opposite ends of the outer tether and the inner tether are connected to a portion of the cushion that faces a forward restraining section inside the cushion.

12. The airbag device according to claim 8 further comprising, the one end of the inner tether having a greater first vertical dimension than a second vertical dimension of the one end of the outer tether.

13. The airbag device according to claim 8 further comprising, a second end of the inner tether and a second end of the outer tether are affixed to a base part of the airbag.

14. The airbag device according to claim 8 further comprising, one of a second end of the inner tether and a second end of the outer tether is affixed to a base part of the airbag and one of another end of the second end of the inner tether and the second end of the outer tether is affixed to another of the inner tether or the outer tether.