Hybrid (augmented) gas generator

• US 5,456,492 A
• Filed: 05/23/1994
• Issued: 10/10/1995
• Est. Priority Date: 12/14/1992
• Status: Expired due to Term

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Morton International Incorporated (Autoliv Incorporated)
• Inventors: Wong, Michael H., Smith, Bradley W., Clark, Randall J., Kort, Leland B.
• Primary Examiner(s): Tyson, Karin L.
• Application Number:
  US08/247,785
• Time in Patent Office: 505 Days
• Field of Search: 280/737, 280/741, 280/740, 280/728 R, 222/3, 137/68.2, 137/68.1
• US Class Current: 280/737
• CPC Class Codes: B60R 2021/26064 characterised by auto-ignition means
• CPC Class Codes: B60R 21/26 characterised by the inflation fluid source or means to control inflation fluid flow arrangement or mounting thereof to the vehicle B60R21/20; blasting cartridges for producing gas under pressure in general F42B3/04; initiators or igniters therefor F42B3/10
• CPC Class Codes: B60R 21/261 with means other than bag structure to diffuse or guide inflation fluid
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: B60R 21/272 with means for increasing the pressure of the gas just before or during liberation, e.g. hybrid inflators
• CPC Class Codes: Y10T 137/1647 Explosive actuation

Abstract

A hybrid gas generator includes a chamber for storing inert gas under high pressure, a chamber for storing pyrotechnic material used to heat the stored gas, a diffuser which contains gas orifices for dispensing gas uniformly into an air bag assembly, a thin metal diaphragm to provide a pressure seal between the storage chamber and the diffuser, and a metal disk that is scored with a circular groove to seal the pyrotechnic material from the stored gas. Upon receiving an electrical signal an initiator fires and ignites the pyrotechnic charge. As pressure in the combustion chamber rises and exceeds the pressure in the storage chamber the metal disk that is scored with a circular groove ruptures and allows hot gas and burning pyrotechnic material to heat the gas and cause a rapid pressure rise in the gas storage chamber. When the pressure in the gas storage chamber exceeds the rupture pressure of the thin metal diaphragm between the storage chamber and the diffuser, it ruptures and allows the heated gas to vent through the diffuser orifices into the air bag assembly. Other features include the use of metal stampings for many of the parts instead of machined or forged parts, an end plug made in one piece with the storage chamber which reduces the number of bulkhead welds, a dimpled or pronged orifice plate which prevents the exiting orifice from being plugged, and a perforated diffuser with small holes which prevent fragments from escaping the inflator without the use of screens or meshes.

Claims

1. A hybrid inflator for an air bag comprising,

a storage chamber for storing inflation gas under high pressure, said storage chamber being formed by a hollow cylindrical sleeve that is closed at one end and open at an opposite end,

a pyrotechnic heater closing said opposite end of said sleeve, said pyrotechnic heater being recessed into said sleeve and including a combustion chamber having a pyrotechnic charge therein, a nozzle orifice, and a metal burst member attached around the perimeter thereof to an inner portion of said pyrotechnic heater in closing relation to said nozzle orifice and arranged to support pressure from the direction of said gas storage chamber but not from said combustion chamber of said pyrotechnic heater,

a diffuser having a plurality of orifices for dispensing inflation gas from said storage chamber uniformly into an air bag,

a diaphragm, and

an orifice plate,

wherein said diffuser includes a controlling orifice to which said diaphragm is attached in a sealing relation, and

wherein said orifice plate is pronged to prevent plugging of said controlling orifice,

parts of said storage chamber, said pyrotechnic heater and said diffuser being made from metal stampings instead of machined or forged parts,

said storage chamber being sealed from said diffuser by said diaphragm and being further sealed from said combustion chamber by said metal burst member against the high pressure of the inflation gas stored in said storage chamber,

whereby as the pressure in the combustion chamber rises and exceeds the pressure of the stored inflation gas in said storage chamber upon ignition of said pyrotechnic charge,

said metal burst member ruptures since it is unsupported when the pressure in said combustion chamber exceeds the pressure in said storage chamber, and hot gas from the burning pyrotechnic charge heats the stored inflation gas in said storage chamber causing a rapid pressure rise therein so that when the pressure in said storage chamber exceeds the structural capability of said diaphragm rupture of the latter occurs allowing the heated gas to vent through said diffuser orifices into an air bag.

2. A hybrid inflator for an air bag comprising,

a storage chamber for storing inflation gas under high pressure, said storage chamber being formed by a hollow cylindrical sleeve that is closed at one end and open at an opposite end,

a pyrotechnic heater closing said opposite end of said sleeve, said pyrotechnic heater being recessed into said sleeve and including a combustion chamber having a pyrotechnic charge therein, a nozzle orifice, and a metal burst member attached around the perimeter thereof to an inner portion of said pyrotechnic heater in closing relation to said nozzle orifice and arranged to support pressure from the direction of said gas storage chamber but not from said combustion chamber of said pyrotechnic heater,

a diffuser having a plurality of orifices for dispensing inflation gas from said storage chamber uniformly into an air bag,

a diaphragm, and

an orifice plate,

wherein said diffuser includes a controlling orifice to which said diaphragm is attached in sealing relation, and

wherein said orifice plate is dimpled to prevent plugging of the controlling orifice,

said metal burst member ruptures since it is unsupported when the pressure in said combustion chamber exceeds the pressure in said storage chamber, and hot gas from the burning pyrotechnic charge heats the stored inflation gas in said storage chamber causing a rapid pressure rise therein so that when the pressure in said storage chamber exceeds the structural capability of said diaphragm rupture of the latter occurs allowing the heated gas to vent through said diffuser orifices into an air bag.

3. A hybrid inflator for an air bag comprising,

a storage chamber for storing inflation gas under high pressure, said storage chamber being formed by a hollow cylindrical sleeve that is closed at one end and open at an opposite end,

a pyrotechnic heater closing said opposite end of said sleeve, said pyrotechnic heater being recessed into said sleeve and including a combustion chamber having a pyrotechnic charge therein, a nozzle orifice, and a metal burst member attached around the perimeter thereof to an inner portion of said pyrotechnic heater in closing relation to said nozzle orifice and arranged to support pressure from the direction of said gas storage chamber but not from said combustion chamber of said pyrotechnic heater,

a diffuser having a plurality of orifices for dispensing inflation gas from said storage chamber uniformly into an air bag, and

a diaphragm,

parts of said storage chamber, said pyrotechnic heater and said diffuser being made from metal stampings instead of machined or forged parts,

said storage chamber being sealed from said diffuser by said diaphragm and being further sealed from said combustion chamber by said metal burst member against the high pressure of the inflation gas stored in said storage chamber,

whereby as the pressure in the combustion chamber rises and exceeds the pressure of the stored inflation gas in said storage chamber upon ignition of said pyrotechnic charge said metal burst member ruptures since it is unsupported when the pressure in said combustion chamber exceeds the pressure in said storage chamber, and hot gas from the burning pyrotechnic charge heats the stored inflation gas in said storage chamber causing a rapid pressure rise therein so that when the pressure in said storage chamber exceeds the structural capability of said diaphragm rupture of the latter occurs allowing the heated gas to vent through said diffuser orifices into an air bag,

wherein said cylindrical sleeve of said storage chamber is closed at said one end by material that is formed in one piece with said cylindrical sleeve,

wherein said diffuser includes a diaphragm/orifice assembly that is located inside said storage chamber and enables said diffuser to have a reduced height externally of said storage chamber,

further including an orifice plate,

wherein said diffuser includes a controlling orifice to which said diaphragm is attached in a sealing relation, and

wherein said orifice plate is pronged to prevent plugging of said controlling orifice,

wherein said diffuser is perforated with holes small enough to prevent the passage of fragments of metal therethrough, and

wherein said metal burst member comprises a metal disk having a circular groove and which is attached around the perimeter thereof to an inner portion of said pyrotechnic heater in closing relation to said nozzle orifice with said circular groove located at a diameter that is larger than said nozzle orifice so that said metal disk can support pressure from the direction of said gas storage chamber but is unsupported and ruptures when the pressure in said combustion chamber exceeds the pressure in said storage chamber.

4. A hybrid inflator for an air bag comprising,

a storage chamber for storing inflation gas under high pressure, said storage chamber being formed by a hollow cylindrical sleeve that is closed at one end and open at an opposite end,

a pyrotechnic heater closing said opposite end of said sleeve, said pyrotechnic heater being recessed into said sleeve and including a combustion chamber having a pyrotechnic charge therein, a nozzle orifice, and a metal disk scored with a circular groove and attached around the perimeter thereof to an inner portion of said pyrotechnic heater in closing relation to said nozzle orifice with said circular groove located at a diameter that is larger than said nozzle orifice so that said metal disk can support pressure from the direction of said gas storage chamber,

a diffuser having a plurality of orifices for dispensing inflation gas from said storage chamber uniformly into an air bag,

a diaphragm, and

an orifice

wherein said diffuser includes a controlling orifice to which said diaphragm is attached in sealing relation, and

wherein said orifice plate is pronged to prevent plugging of the controlling orifice,

said storage chamber being sealed from said diffuser by said diaphragm and being further sealed from said combustion chamber by said metal disk against the high pressure of the inflation gas stored in said storage chamber,

whereby as the pressure in the combustion chamber rises and exceeds the pressure of the stored inflation gas in said storage chamber upon ignition of said pyrotechnic charge, said metal disk ruptures since it is unsupported when the pressure in said combustion chamber exceeds the pressure in said storage chamber, and hot gas from the burning pyrotechnic charge heats the stored inflation gas in said storage chamber causing a rapid pressure rise therein so that when the pressure in said storage chamber exceeds the structural capability of said diaphragm rupture of the latter occurs allowing the heated gas to vent through said diffuser orifices into an air bag.

5. A hybrid inflator for an air bag comprising,

a storage chamber for storing inflation gas under high pressure, said storage chamber being formed by a hollow cylindrical sleeve that is closed at one end and open at an opposite end,

a pyrotechnic heater closing said opposite end of said sleeve, said pyrotechnic heater being recessed into said sleeve and including a combustion chamber having a pyrotechnic charge therein, a nozzle orifice, and a metal disk scored with a circular groove and attached around the perimeter thereof to an inner portion of said pyrotechnic heater in closing relation to said nozzle orifice with said circular groove located at a diameter that is larger than said nozzle orifice so that said metal disk can support pressure from the direction of said gas storage chamber,

a diffuser having a plurality of orifices for dispensing inflation gas from said storage chamber uniformly into an air bag,

a diaphragm, and

an orifice plate,

wherein said diffuser includes a controlling orifice to which said diaphragm is attached in sealing relation, and

wherein said orifice plate is dimpled to prevent plugging of the controlling orifice,

said storage chamber being sealed from said diffuser by said diaphragm and being further sealed from said combustion chamber by said metal disk against the high pressure of the inflation gas stored in said storage chamber,

whereby as the pressure in the combustion chamber rises and exceeds the pressure of the stored inflation gas in said storage chamber upon ignition of said pyrotechnic charge, said metal disk ruptures since it is unsupported when the pressure in said combustion chamber exceeds the pressure in said storage chamber, and hot gas from the burning pyrotechnic charge heats the stored inflation gas in said storage chamber causing a rapid pressure rise therein so that when the pressure in said storage chamber exceeds the structural capability of said diaphragm rupture of the latter occurs allowing the heated gas to vent through said diffuser orifices into an air bag.