Air bag device

Abstract

Expansion of an air bag can be smoothly effected even in a small space by controlling the air bag in thickness and introduction of the gas for expansion, and the protection of an occupant can be rapidly implemented with a relatively small volume of the gas. An air bag device comprises a first air chamberfor protection of the chest or the waist of an occupant, a second air chamberfor protection of the head of the occupant, and a lower portion of the diffuser baginterposed therebetween for portioning out gas from an inflator, wherein the second air chamberhas a first tetherforming a gas passagefor guiding gas jetted from gas outlets of the lower portion of the diffuser baginto the second air chamberso as to go around the tether of a head protection region of an air bag, from the back side thereof toward the front side thereof, and has a second tetherfor forming a gap provided at the lower end of the first tetherin the vicinity of the gas outlets, for letting a portion of the gas escape into a front part of the second air chamber