GAS GENERATION FOR A SAFETY DEVICE, THE CHARGE OF WHICH IS INITIATED BY A HEAT-GENERATING MEANS

• US 20100320735A1
• Filed: 02/09/2009
• Published: 12/23/2010
• Est. Priority Date: 02/07/2008
• Status: Active Grant

• Current Assignee: Seva Technologies
• Original Assignee: Autoliv AB (Autoliv Incorporated)
• Inventors: Duvacquier, Daniel, Lelievre, Xavier, Peremarty, Francois, Patton, Yvonnig
• Granted Patent: US 8,708,367 B2
• Time in Patent Office: Days
• US Class Current: 280/741
• CPC Class Codes: B60R 2021/2642 comprising a plurality of combustion chambers or sub-chambers
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: C06D 5/06 by reaction of two or more solids
• CPC Class Codes: F42B 3/04 for producing gas under pressure generators of inflation fluid especially adapted for vehicle air bags B60R21/26

Abstract

The present invention relates to a gas generator (1) for a safety device for a motor vehicle, which comprises at least two distinct chambers respectively designated as first (2) and second (3) chambers, which communicate with each other through at least one opening or nozzle, the first (2) of these chambers being isolated from the outside, the second one (3) a so-called ‘diffusion’ chamber being able to receive gases generated by the combustion of a solid pyrotechnical charge (5) placed in the first chamber (2), and to discharge them towards the outside. It is remarkable in that: said solid charge (5) is a mixture consisting of at least one oxidizing charge and a reducing charge, the oxygen balance of which is equilibrated; a heat-generating means (6) is provided which generates sufficient heat for triggering and sustaining the combustion of said charge (5), this without any other interaction, notably of the chemical type, between this means (6) and this charge (5).

Claims

1-15. -15. (canceled)

16. A gas generator for a safety device for a motor vehicle, the gas generator comprising:

at least a first chamber and a second chambers, the first chamber isolated from the outside, the second chamber in communication with the first chamber;

an energetic charge disposed in the first chamber, the energetic charge being a mixture of at least one oxidizing charge and one reducing charge for which the oxygen balance of the reaction products is equilibrated; and

a heat-generating device for generating sufficient heat for triggering and sustaining the combustion of the energetic charge without any other interaction, notably of a chemical type, between the heat generating device and the energetic charge;

wherein the second chamber receives gases generated by reaction of the energetic charge within the first chamber and the gases are discharged via at least one discharge aperture of the second chamber that is in communication with the outside.

17. The generator according to claim 16, wherein the energetic charge is formed of an assembly of distinct unit charges, the unit charges being each separated from the next and from the previous one by a destructible screen which provides low resistance to heat.

18. The generator according to claim 16, wherein the energetic charge includes a solid mixture of ammonium nitrate/guanidine nitrate.

19. The generator according to claim 18, wherein the solid mixture comprises 33 to 53% of ammonium nitrate and 47 to 67% of guanidine nitrate providing an oxygen balance equilibrated to within ±

5%.

20. The generator according to claim 16, wherein the energetic charge is in the form of an aqueous solution.

21. The generator according to claim 20, wherein the aqueous solution comprises 65 to 75% of water and 25 to 35% of CaCl₂.

22. The generator according to claim 16, wherein the heat generating device is a pyrotechnical charge contained in a third chamber isolated from the outside which at least indirectly communicates through at least an opening or nozzle with the first and second chambers.

23. The generator according to claim 22, wherein the pyrotechnical charge of the heat generating device is formed with an energetic charge of the propellant type.

24. The generator according to claim 16, wherein the generator is of the tubular type.

25. The generator according to claim 24, wherein the generator is of the tubular type and the screen has a contour which substantially corresponds to a cross-section of the first chamber.

26. The generator according to claim 22, wherein the second and third chambers surround the first chamber.

27. The generator according to claim 26, wherein the charge is circumferentially distributed inside the first chamber, so as to generate a generally axial charge-free channel which has the second and third chambers communicate with each other.

28. The generator according to claim 27, wherein the first chamber includes means for retaining the charge permeable to heat and to gases.

29. The generator according to claim 22, wherein the generator assumes a discoidal shape.

30. The generator according to claim 16, wherein the heat-generating device is a non-chemical device which acts by one of radiation, convection and conduction.