In an airbag device of the present invention, in an inner portion in a car width direction of at least one of adjacent two seats in a vehicle, a central airbag ( 4 ) is housed which is connected to a side face ( 200 ) of a seat frame ( 20 ) of the seat through a predetermined connecting member. On an outer face inside in the car width direction of the central airbag ( 4 ), a plurality of tethers ( 41 ), . . . are provided. This central airbag ( 4 ) counteracts a force from inside in the car width direction with tensions of the tethers ( 41 ), . . . and counteracts a force from outside in the car width direction with a force received from the side face ( 200 ) of the seat frame in inflation and extension.
1. An airbag device comprising:
a side-collision detecting means for detecting a side collision of a vehicle;
a central airbag housed in an inner portion in a car width direction of at least one of two adjacent seats in the vehicle;
a seat frame for the seat;
a connecting member connecting the airbag to a side face of the seat frame, said connecting member being fixed to the airbag at a connection point so that the airbag has a base end side with respect to the connection point in a front-back direction of an inflated airbag;
a tether provided along an outer face of the inflated airbag located at a side opposite to the seat, said tether extending from the connecting member to a distal end portion of the inflated airbag; and
an inflator housed in the seat retaining said central airbag and supplying a gas into said central airbag at a side collision of the vehicle,
wherein said tether has a length shorter than a length along the outer surface of the inflated airbag from the connection point to the distal end portion so that said central airbag counteracts a force from inside in the car width direction by a tension due to the length of said tether and counteracts a force from outside in the car width direction by a force received from a side face of the base end side of said seat frame during inflation and extension.
2. The airbag device according to claim 1 , further comprising
a plate to be brought into planar contact with a base-end side curved face of said central airbag between said seat frame and said central airbag when receiving a force from the outside in the car width direction.
3. The airbag device according to claim 2 , wherein
a pressure sensor is provided on said plate at a position of the planar contact with the base-end side curved face of said central airbag so that said pressure sensor detects a pressure received from said central airbag; and
plate control means for displacing said plate according to a pressure detected by said pressure sensor is further provided.
4. The airbag device according to claim 3 , wherein
said plate is installed between said seat frame and said tether;
said plate, said seat frame and said tether are connected through the connecting member; and
said plate control means rotates said plate around said connecting member according to the pressure detected by said pressure sensor.
5. The airbag device according to claim 1 , further comprising
a door-side airbag which is housed in a side face portion on a vehicle door side of each of said two seats and is inflated and expanded at a side collision of the vehicle.
6. The airbag device according to claim 1 , further comprising another tether provided on an outer face of the inflated airbag at a side of the seat, and having a lug portion connected to the connecting member.