AIRBAG ASSEMBLY

• US 20110018240A1
• Filed: 07/23/2010
• Published: 01/27/2011
• Est. Priority Date: 07/23/2009
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Scott, Timothy, Marable, Paul Mark, Bosio, Allen C.
• Granted Patent: US 8,282,122 B2
• Time in Patent Office: Days
• US Class Current: 280/728.3
• CPC Class Codes: B60R 2021/23324 Inner walls crating separate compartments, e.g. communicating with vents
• CPC Class Codes: B60R 2021/23386 External tether means
• CPC Class Codes: B60R 2021/23504 characterised by material
• CPC Class Codes: B60R 21/231 characterised by their shape, construction or spatial configuration
• CPC Class Codes: B60R 21/233 comprising a plurality of individual compartments; comprising two or more bag-like members, one within the other B60R21/232 takes precedence
• CPC Class Codes: B60R 21/2338 Tethers
• CPC Class Codes: B60R 21/239 characterised by their venting means

Abstract

An airbag assembly for a motor vehicle is disclosed having an airbag 110 that is inflated by an inflator when the airbag 110 is deployed in accordance with a control signal from an electronic controller. The airbag 110 has a main chamber 114 and at least one subsidiary chamber 116 fluidly connected to the main chamber 114 by a transfer vent 117. The main and subsidiary chambers 114 and 116 are vented to atmosphere by respective vents 115, 118 and the pressure in the subsidiary chamber 116 is arranged to be equal to or lower than the pressure in the main chamber 114. The subsidiary chamber 116 is produced in a simple manner by forming a depression in the main chamber 114 using a tether 124 and covering the depression so formed with a cover 125.

Claims

1. An airbag comprising:

a main chamber having at least one main vent to vent gas from the main chamber to atmosphere;

at least one subsidiary chamber of considerably smaller volume than the main chamber connected to the main chamber by at least one transfer vent formed in a common wall between the respective subsidiary chamber and the main chamber wherein;

each subsidiary chamber has at least one subsidiary vent to atmosphere, the airbag has a main wall fastened on each longitudinal edge to a respective side wall and at least one tether connected to the main wall to form a depression in the main wall when the airbag is deployed corresponding to the location of each subsidiary chamber and a cover member is attached to the main wall and the two side walls to cover each depression to form the respective subsidiary chamber.

2. The airbag of claim 1 wherein each cover member is sealingly attached around its periphery to the main wall and the two side walls by stitching.

3. The airbag of claim 1 wherein the main wall is fastened along one edge to a left side wall and is fastened along an opposite edge to a right side wall and at least one of the left and right side walls has at least one main vent formed therein.

4. The airbag of claim 1 wherein the main wall is fastened along one edge to a left side wall and is fastened along an opposite edge to a right side wall and at least one of the left and right side walls has at least one subsidiary vent for each subsidiary chamber formed therein.

5. The airbag of claim 1 wherein each cover member is sealingly attached around its periphery to the main wall and the two side walls and in at least one location there is a length of the periphery of the cover member that is not sealingly attached to form a subsidiary vent.

6. The airbag of claim 1 wherein each cover member is made from gas permeable fabric so that the cover member itself forms the subsidiary vent for the respective subsidiary chamber.

7. The airbag of claim 1 wherein each cover member is attached around its periphery to the main wall and the two side walls by stitching it in place and the pitch of the stitches used to attach the cover member is large to provide a controlled gas leak that forms the subsidiary vent when the respective subsidiary chamber is inflated.

8. The airbag of claim 1 wherein the peak inflation pressure in the main chamber is greater than the peak inflation pressure in each subsidiary chamber.

9. The airbag of claim 1 wherein the ratio of the peak inflation pressure in the main chamber to the peak inflation pressure in a respective subsidiary chamber is based upon the relative total effective cross-sectional areas of all vents for the main chamber and all vents in the respective subsidiary chamber and the total effective cross-sectional area of the transfer vent fluidly connecting the main chamber to the respective subsidiary chamber and the relative volumes of the main chamber and each subsidiary chamber.

10. The airbag of claim 1 wherein at least one of the vents is a self-regulating vent arranged to automatically reduce the flow of gas from one of the chambers of the airbag during deflation of the airbag.

11. The airbag of claim 10 wherein the at least one self-regulating vent is operable to maintain the pressure in the main chamber at a higher level during a final phase of airbag deflation to extend the period of protection provided by the main chamber.

12. The airbag of claim 10 wherein the self-regulating vent is controlled by the gas flowing through the vent and is arranged to automatically reduce the flow area of the vent when the pressure of the gas flowing through the vent falls thereby further reducing the flow of gas through the vent.

13. The airbag of claim 10 wherein the self-regulating vent is controlled by the tension in a tether attached to the vent and is arranged to automatically increase the restriction to flow when the tension in the tether reduces during deflation of the airbag.

14. An airbag assembly, comprising:

a main chamber having a main vent to atmosphere;

a subsidiary chamber of lesser volume than the main chamber connected to the main chamber by a transfer vent formed in a common wall between the subsidiary chamber and the main chamber wherein;

the subsidiary chamber has at least one subsidiary vent to atmosphere, and

the airbag has a main wall fastened on each longitudinal edge to a respective side wall and a tether connected to the main wall to form a depression in the main wall when the airbag is deployed.

15. The airbag assembly of claim 14, further comprising:

an inflator coupled to the main chamber.

16. The airbag assembly of claim 14, further comprising:

an inflator coupled to the main chamber; and

a cover member attached to the main wall and the two side walls to cover each depression to form the subsidiary chamber.

17. The airbag of claim 16 wherein the cover member is made from gas permeable fabric.

18. The airbag of claim 16 wherein the cover member is attached around its periphery to the main wall and the two side walls by stitching.

19. The airbag of claim 18 wherein the pitch of the stitches used to attach the cover member is selected to provide a controlled gas leak to form the subsidiary vent.

20. The airbag assembly of claim 14 wherein at least one of the vents is a self-regulating vent arranged to reduce the flow of gas from one of the chambers of the airbag during deflation of the airbag.