Patent ID: 8056923

Claim:
A side airbag apparatus for a vehicle having a side airbag attached to a side of a backrest part of a vehicle seat at a position above a hinge mechanism which is mounted on a lower part of the backrest, the apparatus comprising: separation means formed along a line running downward from a top extremity of the side airbag to a point ending above a bottom extremity thereof and defining a front airbag chamber and a rear airbag chamber within the side airbag, the rear airbag chamber having a trailing edge, wherein the separation means and the trailing edge define a downflow channel leading to a lower airbag part inflating into an area adjacent to a seat cushion, a connecting passage connecting the front and rear airbag chambers adjacent a lower extremity of the separation means, an attaching portion provided on an upper rear portion of the rear airbag chamber and attaching the side airbag to the backrest part, and an inflator proximate the attaching portion for injecting a gas into the rear airbag chamber which is directed through the downflow channel and the lower airbag part in a predominantly downward direction and inflates the lower airbag part before inflating the front airbag chamber, and wherein the rear airbag chamber has a larger volumetric capacity in the vicinity of the attaching portion at the upper portion of the rear airbag chamber than in the vicinity of the connecting passage in the lower airbag part.