US Patent 7195275 Airbag and airbag apparatus

An airbag includes, when expanded, a center portion of an occupant-side front panel that is stretched by tethers toward a rear side of the airbag. The concave portion formed at the center portion of the front panel caves to the rear side of the airbag from a peripheral portion of the front panel. A covering lid panel traverses the concave portion. The airbag efficiently protects an occupant, even though the concave portion caves away from the occupant. Because the airbag has a volume that is smaller to the extent of the concave portion, the airbag immediately expands even when a gas generator with relatively low output is used.