Patent ID: 8424908
Filing Date: 2013-04-23
Classification: B60R

Abstract:
1. A gas generator for a restraining device of a vehicle, comprising: a housing formed by a cup-shaped closure shell, a cup-shaped diffuser shell having a plurality of gas discharge ports on a side surface portion thereof, and a flange portion having a hole for fixing the gas generator; a cup-shaped inner tube member disposed inside the housing, defining therein an ignition device chamber for accommodating an igniter coaxially with a central axis of the housing, and defining, in an outside thereof, a combustion chamber charged with a gas generating agent; the cup-Shaped inner tube member having a bottom surface located adjacent to a bottom plate side of the diffuser shell, an opening portion located at a bottom plate of the closure shell and a first cutout portion formed at an end portion of the opening portion, for allowing a combustion product generated in the ignition device chamber to pass therethrough; the igniter attached to the closure shell such that the igniter projects inside from a hole formed in the bottom plate of the closure shell; the cup-shaped inner tube member fixed to an igniter attaching portion which comprises a cylindrical portion projecting inwardly, and a passage for a combustion product formed between the cup-shaped inner tube member and the igniter attaching portion to reach the first cutout ventilating portion; the combustion chamber having an outer circumferential surface formed by an outer circumference cylindrical member, an inner circumferential surface formed by the inner tube member, a bottom surface formed by the bottom plate of the closure shell and a top surface formed by an annular porous member provided between the outer circumferential surface and the inner circumferential surface, the annular porous member being provided with a first annular planar portion having a plurality of first holes, and a first annular inside wall surface portion formed on an inner circumference of the first annular planar portion and abutting with the inner tube member; a gas discharge path formed between the outer circumference cylindrical member and a side surface of the diffuser shell, one end of an opening portion of the outer circumference cylindrical member located at the bottom plate of the closure shell, a rim of the other end opening portion of the other circumference cylindrical member having a second cutout portion; the plurality of first holes being smaller than the size of the gas generating agent, and the annular porous member being disposed such that a space is formed between the annular porous member and the bottom plate of the diffuser shell; the space defined by the outer circumference cylindrical member, the bottom plate of the diffuser shell and the annular porous member; the space, along with the second cutout portion of the outer circumference cylindrical member, being communicated with the gas discharge path; and a total opening area of the plurality of gas discharge ports is smaller than a total opening area of a gas pathway extending from the combustion chamber to the gas discharge ports to increase a time period during which the combustion gas is in contact with wall surfaces forming the gas pathway extending from the combustion chamber to the gas discharge ports by increasing a time period during which the combustion gas passes through the gas pathway, wherein no means for cooling and filtering a gas generated by combustion of the gas generating agent is provided other than the annular porous member.