Stamped metal toroidal hybrid gas generator with sliding piston

A hybrid inflator for a vehicle occupant restraint system comprising:

• A) a housing formed of welded-together metal stampings, the housing defining a toroidal gas chamber surrounding a center tie and storing pressurized gas therein;
• B) the center tie having a generally cylindrical sidewall and an outlet wall at an upper end thereof, the outlet wall defining a rupturably sealed outlet orifice;
• C) an inverted stamped metal cup having a generally cylindrical sidewall matingly received in the generally cylindrical sidewall of the center tie,
• 1) the inverted cup having an end wall extending across the center tie to define, together with an upper portion of the center tie sidewall and the outlet wall, an outlet cavity,
• 2) the inverted cup having a lip adjacent its open end welded to the lower end of the center tie,
• 3) the sidewall of the inverted cup including a circumferential groove for separating a sliding piston portion of the inverted cup from the lip under pressure;
• D) a squib support wall closing the lower end of the center tie and inverted cup to define a combustion chamber, and a pyrotechnic gas generant material contained therein, the squib support wall mounting a squib for igniting the pyrotechnic gas generant, wherein upon ignition of the pyrotechnic gas generant, expanding combustion products including hot gas cause the inverted cup to separate at the circumferential groove and drive the sliding piston portion of the inverted cup upwardly in the center tie to an open position;
• E) the center tie defining:
• 1) at least one inlet opening from the combustion chamber to the gas storage chamber and positioned to be exposed for flow of hot gasses from the combustion chamber when the sliding piston portion of the inverted cup is separated from the lip and driven to an open position,
• 2) at least one outlet opening from the gas chamber to the outlet cavity and remaining unblocked by the inverted cup in its open position,
• wherein operation of the squib ignites the pyrotechnic gas generant material to produce hot gasses and expanding combustion products, which separate the inverted cup and drive the sliding piston portion upwardly to the open position, permitting combustion products including hot gasses to flow into the stored gas chamber and heat and thereby increase the pressure of the gas therein, and wherein the sealed outlet orifice rupturably opens after ignition of the pyrotechnic gas generant material, permitting stored gas and combustion products to exit the inflator through the outlet openings, outlet cavity and outlet orifice.

A hybrid inflator for a vehicle occupant restraint system comprising:

• A) a toroidal housing including a centrally disposed generally cylindrical center tie and defining a gas storage chamber surrounding the center tie, and a rupturably sealed outlet orifice communicating with the gas storage chamber;
• B) an ignited assembly received within the center tie, the igniter assembly housing having
• 1) an inverted metal cup having an open rim secured at one end of the center tie and a sliding piston portion integrally connected with the rim at a circumferential groove, the sliding piston closely matingly received in the center tie, wherein the inverted cup and generally cylindrical sidewall of the center tie are tapered to control the speed and extent of sliding motion of the cup in the center tie by deformational and frictional force,
• 2) a squib support wall and squib secured across the rim of the inverted cup, the inverted cup, squib support wall and squib together defining a combustion chamber, and
• 3) a pyrotechnic gas generant material contained within the combustion chamber;
• C) the center tie defining at least one inlet opening into the gas storage chamber from adjacent the groove and the sliding piston portion of the inverted cup;
• wherein when the squib is operated to ignite the pyrotechnic gas generant material, the inverted metal cup separates at the circumferential groove and the sliding piston portion is driven to expose the inlet opening into the gas storage chamber.