Rear seat side airbag device

1. A rear seat side airbag device comprising:

a case that is disposed at a vehicle width direction outer-side of a seatback of a rear seat and including, in vehicle plan view, a bottom wall extending along a vehicle width direction and a pair of side walls extending toward a vehicle front from respective vehicle width direction end portions of the bottom wall, one of the side walls being formed with a shorter vehicle front-rear direction length than the other of the side walls; and

an airbag module that is housed in the case and including a side airbag that deploys at a side portion of an occupant in a collision and an inflator, the inflator supplying gas to the side airbag and including a stud bolt projecting out in a vehicle width direction and fastened to the one side wall or the other side wall by the stud bolt,

wherein:

in vehicle plan view, a length of a line linking respective front ends of the pair of side walls of the case is an opening length; and

in vehicle plan view, a length of a diagonal line linking a corner portion at a vehicle rear end side and one vehicle width direction end side of the airbag module, and a corner portion at a vehicle front end side and the other vehicle width direction end side of the airbag module, is a diagonal length; then

the opening length is formed longer than the diagonal length.

2. The rear seat side airbag device of claim 1 , wherein the side wall at a vehicle width direction inner-side of the case is formed with a shorter vehicle front-rear direction length than the side wall at a vehicle width direction outer-side of the case.

3. The rear seat side airbag device of claim 1 , wherein the inflator is fastened to the side wall at a vehicle width direction outer-side by the stud bolt projecting out toward a vehicle width direction outer-side.

4. The rear seat side airbag of claim 1 , wherein the side garnish is separate from the rear seat.

5. A rear seat side airbag device comprising:

a case that is disposed in a side garnish at a vehicle width direction outer-side of a seatback of a rear seat and including, in vehicle plan view, a bottom wall extending along a vehicle width direction and a pair of side walls extending toward a vehicle front from respective vehicle width direction end portions of the bottom wall and each of the pair of side walls including at least one anchor hook, one of the side walls being formed with a shorter vehicle front-rear direction length than the other of the side walls;

an airbag module that is housed in the case and including a side airbag that deploys at a side portion of an occupant in a collision and an inflator, the inflator supplying gas to the side airbag and including a stud bolt projecting out in a vehicle width direction and fastened to the one side wall or the other side wall by the stud bolt; and

an airbag door garnish including at least one anchor hole formed in each of a pair of vertical wall portions thereof and anchoring a corresponding anchor hook, one of the pair of vertical wall portions being formed with a shorter vehicle front-rear direction length than the other of the pair of vertical wall portions,

wherein:

in vehicle plan view, a length of a line linking respective front ends of the pair of side walls of the case is an opening length; and

in vehicle plan view, a length of a diagonal line linking a corner portion at a vehicle rear end side and one vehicle width direction end side of the airbag module, and a corner portion at a vehicle front end side and the other vehicle width direction end side of the airbag module, is a diagonal length; then

the opening length is formed longer than the diagonal length.

6. The rear seat side airbag device of claim 5 , wherein the side wall at a vehicle width direction inner-side of the case is formed with a shorter vehicle front-rear direction length than the side wall at a vehicle width direction outer-side of the case.

7. The rear seat side airbag device of claim 5 , wherein the inflator is fastened to the side wall at a vehicle width direction outer-side by the stud bolt projecting out toward a vehicle width direction outer-side.

8. The rear seat side airbag of claim 5 , wherein the side garnish is separate from the rear seat.