US Patent 8215665 Airbag device

The present invention obtains an airbag device that can effectively protect an upper body and knees of a passenger by a simple airbag structure. An airbag that structures an airbag device for a passenger's seat has a main bag that restrains an upper body of a vehicle passenger from a front side in a vehicle longitudinal direction, a sub-bag that has a smaller volume than the main bag and that restrains knees of the passenger from the front side in the vehicle longitudinal direction, and an inner tube that is folded-up together with the main bag and the sub-bag and is inflated and expanded within the airbag by a gas supply from an inflator. The inner tube directly supplies gas of the inflator to the main bag and the sub-bag respectively. A check valve is provided at a gas exit that communicates the inner tube with the sub-bag.