RUPTURE FEATURE FOR INFLATOR OF VEHICLE AIRBAG

• US 20110169252A1
• Filed: 01/14/2010
• Published: 07/14/2011
• Est. Priority Date: 01/14/2010
• Status: Active Grant

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Young, Anthony M., Young, Andrew J., Gamill, Kurt L.
• Granted Patent: US 8,371,611 B2
• Time in Patent Office: Days
• US Class Current: 280/737
• CPC Class Codes: B60R 21/262 Elongated tubular diffusers, e.g. curtain-type
• CPC Class Codes: B60R 21/274 characterised by means to rupture or open the fluid source
• CPC Class Codes: Y10T 137/1692 Rupture disc
• CPC Class Codes: Y10T 137/1744 Specific weakening point

Abstract

A rupture feature releases pressurized gas into a diffuser through an egress opening in an inflator wall responsive to a pressure impulse in the inflator. A sturdy rupture fragment is positioned opposite the egress opening. A thin rupture membrane continuously circumscribes and sealingly interconnects the rupture fragment to the inflator about the egress opening. Rupture membrane thickness is less than rupture fragment thickness or inflator wall thickness at the egress opening. The rupture membrane is upstanding from the inflator wall about the egress opening to a constant height. The rupture fragment and the rupture membrane are integrally-formed with each other and with the inflator wall at the egress opening. The pressure impulse impacts the rupture fragment, urges the rupture fragment away from the inflator, detaches the rupture fragment from the inflator by fully transversely fracturing the rupture membrane, and drives the rupture fragment into containment within the diffuser.

Claims

1. A rupture feature for releasing pressurized gas from an inflator for a vehicle passenger safety airbag, the rupture feature discharging the pressurized gas into a diffuser through an egress opening in the wall of the inflator responsive to a predetermined pressure impulse arising in the inflator, the rupture feature comprising:

(a) a sturdy rupture fragment of reliably stable configuration positioned opposite the egress opening in an orientation to be impacted by the predetermined pressure impulse; and

(b) a relatively thin rupture membrane continuously circumscribing the rupture fragment and sealingly interconnecting the rupture fragment to the wall of the inflator about the egress opening.

2. A rupture feature as recited in claim 1, wherein the thickness of the rupture membrane is less than the thickness of the rupture fragment and less than the thickness of the wall of the inflator at the egress opening.

3. A rupture feature as recited in claim 1, wherein the rupture membrane is upstanding from the wall of the inflator about the egress opening.

4. A rupture feature as recited in claim 3, wherein the height of the rupture membrane measured between the wall of the inflator and the periphery of the rupture fragment is constant about the egress opening.

5. A rupture feature as recited in claim 1, wherein the rupture membrane is integrally formed with the wall of the inflator and with the rupture fragment.

6. A rupture feature as recited in claim 1, wherein the rupture fragment is circularly symmetric.

7. A rupture feature as recited in claim 1, wherein the rupture fragment is substantially planar.

8. A rupture feature as recited in claim 1, wherein impact of the predetermined pressure impulse against the rupture fragment urges the rupture fragment away from the inflator, detaching the rupture fragment from the inflator by fully transversely fracturing the rupture membrane.

9. A rupture feature as recited in claim 8, wherein the fracturing of the rupture membrane permits the predetermined pressure impulse to drive the rupture fragment into the diffuser.

10. A pressurized gas release and diffusion assembly for a gas egress opening in the wall of the inflator for a vehicle passenger safety airbag, the assembly comprising:

(a) a gas guide secured to the exterior of the wall of the inflator about the egress opening;

(b) a generally planar rupture fragment of reliably stable configuration mechanically associated with the inflator wall interior of the gas guide, the rupture fragment being positioned generally parallel to the transverse plane of the egress opening intermediate the egress opening and the gas guide; and

(c) a continuous rupture membrane formed with the inflator wall and with the rupture fragment sealingly interconnecting the periphery of the rupture fragment to the wall of the inflator about the egress opening.

11. An assembly as recited in claim 10, wherein the gas guide comprises:

(a) an end wall separated from and opposing the egress opening;

(b) a continuous skirt having a first edge circumscribing the periphery of the end wall and a second edge opposite therefrom attached to the exterior of the wall of the inflator about the egress opening; and

(c) a plurality of circumferentially-spaced diffusion apertures formed through the skirt, the diffusion apertures affording escape radially outwardly from the assembly for pressurized gas from the inflator.

12. An assembly as recited in claim 10, wherein the thickness of the rupture membrane is less than the thickness of the rupture fragment and less than the thickness of the wall of the inflator at the egress opening.

13. An assembly as recited in claim 10, wherein pressurized gas in the inflator is released and diffused responsive to a predetermined pressure impulse arising in the inflator, the predetermined pressure impulse urging the rupture fragment away from the inflator, detaching the rupture fragment from the inflator at the rupture membrane, and driving the rupture fragment against an inner surface of the gas guide.

14. A release structure for pressurized gas in an inflator for a vehicle passenger safety airbag, the release structure opening responsive to a predetermined pressure impulse arising in the inflator, and the release structure comprising:

(a) a gas egress opening formed through the wall of the inflator;

(b) a barrier positioned opposite the egress opening in an orientation to be impacted by the predetermined pressure impulse; and

(c) a frangible sleeve sealingly interconnecting the periphery of the barrier to the wall of the inflator about the egress opening.

15. A release structure as recited in claim 14, wherein the thickness of the frangible sleeve is less than the thickness of the barrier and less than the thickness of the wall of the inflator at the egress opening.

16. A release structure as recited in claim 14, wherein impact of the predetermined pressure impulse against the barrier urges the barrier outwardly from the inflator, detaching the barrier from the inflator by fully transversely fracturing the frangible sleeve.

17. A release structure as recited in claim 14, further comprising a gas guide secured to the exterior of the wall of the inflator enclosing the barrier and the frangible sleeve, the gas guide comprising:

(a) an end wall separated from and opposing the barrier;

(b) a continuous skirt having a first edge circumscribing the periphery of the end wall and a second edge opposite therefrom attached to the exterior of the wall of the inflator about the frangible sleeve; and

(c) a plurality of circumferentially-spaced diffusion apertures formed through the skirt of the gas guide, the diffusion apertures affording escape radially outwardly from the release structure for pressurized gas from the inflator.

18. A method for manufacturing a rupture feature for an inflator for a vehicle passenger safety airbag, the method comprising the steps of:

(a) developing a gas egress opening through a wall of the inflator;

(b) enclosing the egress opening from the exterior of the inflator in a hollow boss having a closed top remote from the inflator and a continuous sidewall sealingly connecting the top of the boss to the wall of the inflator about the egress opening; and

(c) thinning the sidewall of the boss to such an extent that a predetermined pressure impulse arising in the inflator will, by urging the top of the boss away from the inflator, detach the top of the boss from the wall of the inflator by fully transversely fracturing the sidewall of the boss.

19. A method as recited in claim 18, further comprising the step of securing to the exterior of the wall of the inflator about the boss a gas guide comprising:

(a) an end wall separated from and opposing the top of the boss;

(b) a continuous skirt having a first edge circumscribing the end wall of the gas guide and a second edge opposite therefrom attached to the exterior of the wall of the inflator about the sidewall of the boss; and

(c) a plurality of circumferentially-spaced diffusion apertures formed through the skirt of the gas guide, the diffusion apertures affording escape radially outwardly from the gas guide for pressurized gas from the inflator.

20. A method as recited in claim 18, wherein the step of developing and the step of enclosing are performed simultaneously in a step of integrally forming the portion of the wall of the inflator at the intended location of the egress opening into the boss.