Hybrid-gas generator, in particular for filling a gas bag

• US 20030150519A1
• Filed: 04/14/2003
• Published: 08/14/2003
• Est. Priority Date: 06/09/2000
• Status: Active Grant

• Current Assignee: Peter Lell
• Original Assignee: Peter Lell
• Inventors: Lell, Peter
• Granted Patent: US 6,739,362 B2
• Time in Patent Office: Days
• US Class Current: 141/313
• CPC Class Codes: B60R 21/272 with means for increasing the pressure of the gas just before or during liberation, e.g. hybrid inflators

Abstract

The invention relates to a hybrid gas generator, in particular for filling a gas bag, comprising a combustion chamber (3) which contains a predetermined amount of a gas generating material (11) and which comprises an outlet opening of the combustion chamber, further comprising an activating device (9) for activating the gas generating material (11) and further comprising a gas vessel (5) containing a stored gas, which is connected with the combustion chamber (3) via the outlet opening of the combustion chamber, which is sealed off in the initial state, and which comprises at least one outlet opening (25) for the gas mixture which is sealed off by means of an outlet membrane (23) in the initial state, wherein the gas that is generated in the combustion chamber (3) after the gas generating material (11) has been activated acts upon a projectile (29) via the outlet opening of the combustion chamber, which projectile is accelerated by the gas pressure and destroys the outlet membrane (23), whereby the gas mixture consisting of the gas generated and the stored gas escapes from the outlet opening (25). According to the invention, the outlet opening of the combustion chamber runs into the interior space of the gas vessel (5) via a guide channel (21) having a predetermined length, and the projectile is formed as a projectile (29) which is separate in the initial state and is provided in the guide channel (21), the projectile (29) being located in the guide channel such that it keeps a distance from the outlet opening of the guide channel (21) by a predetermined barrel length in the initial state. According to the invention, a membrane (31) is provided between the projectile (29) and the combustion chamber (3), which, as soon as a predetermined threshold pressure of the gas generated in the combustion chamber (3) is exceeded, is destroyed by this pressure, whereby the projectile (29) is immediately acted upon and accelerated by the pressure of the gas generated which exceeds the threshold pressure. Furthermore, the invention relates to a hybrid gas generator in which no separate projectile is provided. Instead, a membrane is used which is formed such that at least the part of the membrane which closes the cross-section of the guide channel is broken out of the membrane substantially in one piece and serves as a projectile once a predetermined threshold pressure of the gas generated in the combustion chamber is exceeded.

Claims

1. A hybrid gas generator, in particular for filling a gas bag,

a) comprising a combustion chamber (3) which contains a predetermined amount of a gas generating material (11) and which comprises an outlet opening of the combustion chamber,

b) further comprising an activating device (9) for activating the gas generating material (11) and

c) further comprising a gas vessel (5) containing a stored gas, which is connected with said combustion chamber (3) via said outlet opening of the combustion chamber, which is sealed off in the initial state, and which comprises at least one outlet opening (25) for the gas mixture which is sealed off by means of an outlet membrane (23) in the initial state,

d) wherein the gas that is generated in said combustion chamber (3) after said gas generating material (11) has been activated acts upon a projectile (29) via said outlet opening of the combustion chamber, which projectile is accelerated by the gas pressure and destroys said outlet membrane (23), whereby the gas mixture consisting of the gas generated and the stored gas escapes from said outlet opening (25),

characterized in that

e) said outlet opening of the combustion chamber runs into the interior space of said gas vessel (5) via a guide channel (21) having a predetermined length,

f) that said projectile is configured as a projectile (29) which is separate in the initial state and is provided in said guide channel (21), said projectile (29) being located in said guide channel such that it keeps a distance from the outlet opening of said guide channel by a predetermined barrel length in the initial state, and

g) that a membrane (31) is provided between said projectile (29) and said combustion chamber (3), which, as soon as a predetermined threshold pressure of the gas generated in said combustion chamber (3) is exceeded, is destroyed by this pressure, whereby said projectile (29) is immediately acted upon and accelerated by the pressure of the gas generated which exceeds the threshold pressure.

2. A gas generator according to claim 1, characterized in that said projectile (29) comprises a preferably centric or ring-shaped recess in its end that is to be acted upon by the accelerating pressure, and that the remaining outer wall of said projectile (29) is formed such that it is pressed against the inner wall of said guide channel (21), being deformed elastically or plastically, if the recess is acted upon by the accelerating pressure, so as to create a sealing effect.

10. A gas generator according to one of the preceding claims, characterized in that the cross-section of said guide channel (21) is set to a value which ensures that the maximum working pressure generated in said gas vessel (5) after said gas generating material (11) has been activated is below a predetermined value, preferably lower than 300 to 400 bar.

11. A gas generator according to one of the preceding claims, characterized in that the barrel length for the projectile is determined to be such that the kinetic energy of the projectile is sufficient to securely destroy said outlet membrane (23) when the projectile hits it.

12. A gas generator according to one of the preceding claims, characterized in that said outlet membrane (23) is configured and designed such that it is destroyed as soon as a critical pressure of the mixture of stored gas and gas generated is exceeded in said gas vessel (5) even without being destroyed by said projectile.

13. A gas generator according to one of the preceding claims, characterized in that the pressure resistance, in particular the wall thickness, of said gas vessel (5) is designed for the maximum working pressure or the critical pressure in consideration of a safety reserve.

14. A gas generator according to one of the preceding claims, characterized in that said gas vessel (5) is configured to be tube-shaped.

15. A gas generator according to claim 14, characterized in that said guide channel (21) is provided in a disk-like end piece (19) that is connected with the corresponding end of a tube or is integrally formed therewith.

16. A gas generator according to claim 15, characterized in that said combustion chamber (3) is configured to be tube-shaped, wherein a tube section (15) forming the housing of the combustion chamber is preferably connected with the end piece of said gas vessel (5) or is integrally formed therewith.

17. A gas generator according to one of the preceding claims, characterized in that the outlet opening of the combustion chamber is shielded from the solid or liquid particles produced when gas is generated by means of a particle removing device (33), which is arranged in front of the outlet opening of the combustion chamber at a predetermined distance thereto.

18. A gas generator according to claim 17, characterized in that said particle removing device (33) comprises a shielding element (35) configured as a sieve or a filter.

19. A gas generator according to claim 18, characterized in that said shielding element (35) comprises a rebounding portion (37) which covers the outlet opening of the combustion chamber in such a way that a direct, straight entrance of solid or liquid particles into the outlet opening of the combustion chamber or their direct striking of said membrane (31, 31′

) is avoided.

20. A gas generator according to one of claims 17 to 19, characterized in that at least the portion surrounding the outlet opening of the combustion chamber and/or said rebounding portion (35) of said shielding element, which are subjected to being hit by solid particles, consist of a material in which some of the particles penetrate and remain trapped and from which some of the particles rebound, potentially after having burst once they hit the aforesaid portions.

3. A hybrid gas generator, in particular for filling a gas bag,

a) comprising a combustion chamber (3) which contains a predetermined amount of a gas generating material (11) and which comprises an outlet opening of the combustion chamber,

b) further comprising an activating device (9) for activating the gas generating material (11) and

c) further comprising a gas vessel (5) containing a stored gas, which is connected with said combustion chamber (3) via said outlet opening of the combustion chamber, which is sealed off in the initial state, and which comprises at least one outlet opening (25) for the gas mixture which is sealed off by means of an outlet membrane (23) in the initial state,

d) wherein the gas that is generated in said combustion chamber (3) after said gas generating material (11) has been activated acts upon a projectile (29) via said outlet opening of the combustion chamber, which projectile is accelerated by the gas pressure and destroys said outlet membrane (23), whereby the gas mixture consisting of the gas generated and the stored gas escapes from said outlet opening (25),

characterized in that

e) said outlet opening of the combustion chamber runs into the interior space of said gas vessel (5) via a guide channel (21) having a predetermined length,

f) that said guide channel is closed by a membrane (31′

) in the initial state, which is formed such that at least the part of the membrane (31′

) which closes the cross-section of said guide channel (21) is broken out of said membrane (31′

) in one piece and acts as a projectile once a predetermined threshold pressure of the gas generated in said combustion chamber (3) is exceeded.

4. A gas generator according to claim 3, characterized in that said membrane (31′

) has such a thickness in the area of the cross-section of said guide channel (21) or is thickened as compared to the residual portion of said membrane (31′

) that the part of the membrane forming the projectile has a mass which is large enough to ensure that the kinetic energy of the projectile suffices to destroy the outlet membrane (23) when it hits it.

5. A gas generator according to claims 3 or 4, characterized in that said membrane (31′

) is provided at the end of said guide channel (21) on the side of the combustion chamber or inside said guide channel (21), with the portion of said guide channel (21) between the position of said membrane (31) and the end of said guide channel (21) serving as a barrel length for guiding said projectile.

6. A gas generator according to one of claims 3 to 5, characterized in that said membrane (31′

) is acted upon by shearing edges (59) on its front side opposite to said combustion chamber (3).

7. A gas generator according to one of claims 3 to 6, characterized in that said membrane (31′

) is provided on the front side of said guide channel (21) opposite the combustion chamber (3) or at the outlet opening of the combustion chamber.

8. A gas generator according to one of claims 3 to 7, characterized in that means for defining a closed, ring-shaped predetermined breaking point are provided in a front side of said membrane (31′

), preferably a groove or a notch.

9. A gas generator according to claims 7 and 8, characterized in that said membrane (31′

) is connected with the front side of the element containing the guide channel (21) by mean'"'"'s of a ring-shaped weld (61), with the edge portion of the weld (61) on the inside defining the predetermined breaking point.