Patent ID: 8523223

Claim:
A folding method of an airbag comprising a base end chamber in which an inflator is disposed, a left airbag portion opening to the base end chamber for receiving inflation gas from the inflator therein to inflate on the left side in front of an occupant, and a right airbag portion opening to the base end chamber for receiving inflation gas from the inflator therein to inflate on the right side in front of an occupant, comprising the steps of: a primary folding step for forming a primary folded body in which said airbag is substantially flattened along a top-bottom direction and along a right-left direction by folding said airbag in a manner that decreases a thickness of said left airbag portion and said right airbag portion along a substantially front-back direction and at least partially separates a left surface of said left airbag portion and a right surface of said right airbag portion along the right-left direction; and a secondary folding step for forming a final folded body by folding said primary folded body in a manner that decreases its width substantially along the top-bottom direction and along the right-left direction, wherein in said secondary folding step, an upper end portion, a lower end portion, a left end portion, and a right end portion of said primary folded body are each folded toward a center of said primary folded body along the top-bottom direction and along the right-left direction, at least one of an upper end portion, a lower end portion, a left end portion, and a right end portion of said primary folded body is folded toward a center of said primary folded body into a roll shape along the top-bottom direction and along the right-left direction, said primary folded body is folded in a manner that decreases its width along the right-left direction, and subsequently folded in a manner that decreases its width along the top-bottom direction, and wherein said airbag inflates from an instrument panel of a vehicle toward the vehicle rear, bringing said airbag close to an occupant, and further comprises a rearward connection between a right surface of the left airbag portion and a left surface of the right airbag portion rearwardly of the base end chamber that extends in the top-bottom direction for the majority of the width of the inflated left and right airbag portions in the top-bottom direction to form a hollow portion disposed between said left airbag portion and said right airbag portion rearwardly of the base end chamber and forwardly of the rearward connection, that passes substantially vertically through an area surrounded by said airbag when said airbag is in an inflated state; and at least a part of said hollow portion is positioned further toward the vehicle rear than an end portion of the instrument panel on the vehicle rear side when said airbag is in an inflated state.