Side airbag apparatus

A side airbag apparatus comprising:

• an airbag main body including an inflation portion, wherein the inflation portion is inflated by inflation gas supplied thereto in response to an impact applied to a side of a vehicle seat, the airbag main body is deployed forward on the side of the vehicle seat, and wherein the inflation portion includes:
• a first inflation chamber, which is deployed and inflated by being supplied with the inflation gas;
• a second inflation chamber, which is located in front of and adjacent to the first inflation chamber;
• a vertical partition, which separates the first inflation chamber and the second inflation chamber from each other;
• a third inflation chamber, which is adjacent to and located above or below the first inflation chamber, wherein the third inflation chamber is deployed and inflated by the inflation gas with an internal pressure that is higher than the inflation pressure of the first inflation chamber;
• and
• a lateral partition, which separates the first inflation chamber and the third inflation chamber from each other,
• wherein the vertical partition and the lateral partition each have an opening;
• a pressure regulator valve provided in the vertical partition, wherein when the first inflation chamber is inflated before starting restraining an occupant, the pressure regulator valve is closed to restrict the inflation gas from flowing from the first inflation chamber to the second inflation chamber through the opening, and when the first inflation chamber restrains the occupant, the pressure regulator valve opens in response to a change in the tensed state of the vertical partition due to an applied external force generated by the restraint, thereby cancelling the restraint, and
• a check valve provided in the lateral partition to restrict flow of the inflation gas from the third inflation chamber to the first inflation chamber.