Side airbag apparatus

A side airbag apparatus attached to a vehicle and including an airbag,

• wherein the airbag is comprised of one pair of main body cloth portions that are overlaid on top of each other in a width direction of a vehicle seat,
• the airbag is formed in a bag shape by joining margins of the one pair of main body cloth portions,
• the airbag is deployed and inflated by inflation gas supplied from an inflator according to an impact given from the side of the vehicle seat,
• the airbag is portioned by a longitudinal partition portion into a rear inflation chamber and a front inflation chamber,
• the longitudinal partition portion is laid between the one pair of main body cloth portions and has a communication hole,
• the rear inflation chamber is arranged behind the longitudinal partition portion,
• the rear inflation chamber receives inflation gas supplied from the inflator,
• the front inflation chamber is arranged in front of the longitudinal partition portion,
• the front inflation chamber receives inflation gas supplied from the rear inflation chamber through the communication hole,
• one of the one pair of main body cloth portions is attached to the vehicle,
• the airbag is attached to the vehicle at a position between a rear end of the main body cloth portion attached to the vehicle and the longitudinal partition portion, and
• the airbag is attached to the vehicle without being inflated so that the airbag inflates both in front of and behind a position of attachment of the airbag to the vehicle,
• the airbag is attached to a seat frame inside the vehicle seat,
• the inflator is arranged at a position between a rear end of the airbag and the longitudinal partition portion inside the airbag,
• the inflator is attached by a locking member to the seat frame together with the main body cloth portion attached to the vehicle, and
• in a state that the airbag is attached to the vehicle without being inflated, the distance between a position where the main body cloth portion is attached to the vehicle and the rear end of the main body cloth portion is larger than the distance between a position where the main body cloth portion is attached to the vehicle and a rear end of the seat frame.