Passenger protection device for front passenger seat

1. A passenger protection device for a front passenger seat, the passenger protection device comprising:

an upper airbag that is:

installed in a front header provided at a front end of a roof of a vehicle, and is configured to inflate and deploy at a time of a frontal collision of a vehicle;

configured to be supported by a windshield from a front side of the vehicle when the upper airbag inflates and deploys at the time of the frontal collision of the vehicle; and

configured so that, when viewed from a vehicle lateral side in the inflated and deployed state, (i) an outer perimeter of the upper airbag has a substantially triangular shape of which a height dimension in a vehicle height direction decreases toward the front side of the vehicle, (ii) a bottom edge of the upper airbag is substantially parallel to a floor of the vehicle, and (iii) a rear surface of the upper airbag faces a head of a front passenger from the front side of the vehicle; and

a lower airbag that is provided separately from the upper airbag and installed at a front end of a vehicle cabin below the windshield of the vehicle in the vehicle height direction, the lower airbag being configured to inflate and deploy at the time of the frontal collision so as to be supported by a dashboard including an instrument panel from the front side of the vehicle,

wherein when the upper airbag and the lower airbag are in an inflated state, a side of the upper airbag facing a rear of the vehicle is closer to the rear of the vehicle than a side of the lower airbag facing the rear of the vehicle,

the upper airbag is configured to inflate and deploy toward a front side of a head of a front passenger at the time of the frontal collision, and

the lower airbag is configured to inflate and deploy toward a front side of left and right lower legs of the front passenger at the time of the frontal collision.

2. The passenger protection device according to claim 1 , wherein:

the upper airbag and the lower airbag are each configured to inflate and deploy so as to form a frame structure upon receiving gas supply respectively from an inflator;

the upper airbag has a first frame-shaped inflation part that forms a framework of the upper airbag, and a plurality of first base fabrics, the plurality of first base fabrics being attached to the first frame-shaped inflation part and forming first walls of the upper airbag; and

the lower airbag has a second frame-shaped inflation part that forms a framework of the lower airbag, and a plurality of second base fabrics, the plurality of second base fabrics being attached to the second frame-shaped inflation part and forming second walls of the lower airbag.

3. The passenger protection device according to claim 2 , wherein:

the plurality of first base fabrics include a first rear base fabric, a first bottom base fabric, a first left base fabric, and a first right base fabric that form a rear wall, a bottom wall, a left wall, and a right wall of the upper airbag, respectively;

the first frame-shaped inflation part is formed so as to surround the first rear base fabric and the first bottom base fabric; and

the first left base fabric and the first right base fabric each have a triangular shape of which two sides of three sides are shorter than the other one side, and edges constituting the two sides of the first left base fabric and edges constituting the two sides of the first right base fabric are joined respectively to left and right side portions of the first frame-shaped inflation part such that the inflated and deployed first frame-shaped inflation part is bent so as to protrude toward a rear lower side of the vehicle as seen from a vehicle width direction, and

the plurality of second base fabrics include a second rear base fabric, a second bottom base fabric, a second left base fabric, and a second right base fabric that form a rear wall, a bottom wall, a left wall, and a right wall of the lower airbag, respectively;

the second frame-shaped inflation part is formed so as to surround the second rear base fabric and the second bottom base fabric; and

the second left base fabric and the second right base fabric each have a triangular shape of which two sides of three sides are shorter than the other one side, and edges constituting the two sides of the second left base fabric and edges constituting the two sides of the second right base fabric are joined respectively to left and right side portions of the second frame-shaped inflation part such that the inflated and deployed second frame-shaped inflation part is bent so as to protrude toward a rear lower side of the vehicle as seen from a vehicle width direction.

4. The passenger protection device according to claim 1 , wherein when the upper airbag and the lower airbag are in an inflated state, a gap is present between the upper airbag and the lower airbag such that the upper airbag and the lower airbag do not contact each other.

5. The passenger protection device according to claim 1 , wherein when the lower airbag is in an inflated state, the lower airbag is completely below the windshield of the vehicle.

6. The passenger protection device according to claim 1 , wherein the upper airbag, when viewed from the vehicle lateral side in the inflated and deployed state, includes an inflatable duct that is inflated into an L-shape, and a non-inflatable fabric section that extends between opposite sides of the L-shape.

7. The passenger protection device according to claim 1 , wherein the upper airbag is formed by an inflatable duct that forms outer edges of the upper airbag, and the inflatable duct inflates into an L-shape, and

the upper airbag includes a non-inflatable rear fabric section that extends vertically and extends between the outer edges formed by the inflatable duct, a non-inflatable bottom fabric section that extends horizontally and extends between the outer edges formed by the inflatable duct, a non-inflatable right fabric section that is triangular and extends between opposite sides of the L-shape, and a non-inflatable left fabric section that is triangular and extends between opposite sides of the L-shape.

8. The passenger protection device according to claim 7 , wherein:

the upper airbag defines an open space that is exposed to the windshield in the inflated and deployed state, and the open space is bounded by the inflatable duct, the non-inflatable rear fabric section, the non-inflatable bottom fabric section, the non-inflatable right fabric section, and the non-inflatable left fabric section.