GB2486207A

GB2486207A - A curtain airbag assembly with deployment tubes

Info

Publication number: GB2486207A
Application number: GB201020629A
Authority: GB
Inventors: Tim Scott; Jamel E Belwafa; Robert William Mccoy; Michal Jan Swiniarski; Barry Grindle
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2010-12-06
Filing date: 2010-12-06
Publication date: 2012-06-13
Anticipated expiration: 2030-12-06
Also published as: RU2011149544A; CN102555976A; GB2486207B; CN102555976B; GB201020629D0

Abstract

A curtain airbag assembly for a motor vehicle is disclosed in which a curtain airbag 30 and inflator 21, securable along an upper edge of a body structure of a motor vehicle, includes at least one inflatable chamber 31, 32 and at least one deployment tube 33-35 to assist with deployment of the airbag, said deployment tube being rapidly inflated so as to pull the curtain airbag quickly into position. The airbag may comprise two inflatable chambers and three deployment tubes, so that each chamber has a tube located to either side. The tubes may be of a small volume compared to the inflatable chamber so that they are more rapidly inflated. The airbag may be connected to the inflator by means of a manifold (22, figure 3) provided with separate outputs (23-27) for the tubes and chambers. The tubes may include one or vents for supplying inflation gas to a lower end of the chambers.

Description

A Curtain Airbag Assembly for a Motor Vehicle This invention relates to motor vehicles and in particular to an improved curtain airbag assembly for a motor vehicle.

It is well known to provide a motor vehicle with a curtain airbag to protect an occupant of the motor vehicle from contact with a side of the motor vehicle during an accident and to prevent a body part of the occupant from passing through a window aperture during a roll-over event.

It is a problem with such curtain airbags that, particularly if the airbag is large, the time taken to deploy the curtain airbag can be considerable unless a very large inflator is used. Such large inflators are difficult to package on a vehicle and are so undesirable. Furthermore the curtain airbag is easily distorted during inflation and so it is possible for it to be pushed out through the window aperture if impacted against before full operating pressure is reached within the airbag.

It is an object of this invention to provide a curtain airbag for a motor vehicle that is deployable more rapidly without the need for a larger inflator and has an improved resistance to extrusion through a window aperture.

According to a first aspect of the invention there is provided a curtain airbag assembly for a motor vehicle having a curtain airbag securable along an upper edge to part of a body structure of the motor vehicle and an inflator to inflate the curtain airbag, the curtain airbag having at least one inflatable chamber arranged so as to extend when deployed in front of at least one window aperture of the motor vehicle to provide protection for an occupant of the motor vehicle and at least one deployment tube formed as part of the airbag to assist with deployment of the airbag wherein the at least one deployment tube is rapidly inflated during deployment of the curtain airbag so as to pull the curtain airbag quickly into position.

The or each deployment tube may extend along substantially the entire length of the airbag.

Each deployment tube may be of a small volume compared to the volume of an inflatable chamber thereby permitting it to be rapidly inflated.

The at least one deployment tube may be formed as an integral part of the airbag.

The inflator may be connected to the airbag via a manifold having separate outputs for the at least one chamber and the at least one deployment tube.

The airbag may have two inflatable chambers and each of the chambers may be bounded on both sides by a respective deployment tube.

The manifold may have a first outlet for supplying gas to a first deployment tube located at one end of the airbag, a second outlet for supplying gas to a second deployment tube located at an opposite end of the airbag, a third outlet for supplying gas to a third deployment tube located between the two inflatable chambers, a fourth outlet tube for supplying gas to one of the two inflatable chambers and a fifth outlet for supplying gas to the other of the two

inflatable chambers.

At least one deployment tube may include one or more vents opened when the respective deployment tube is substantially fully inflated for supplying gas to at least one inflatable chamber.

The one or more vents may supply gas to a bottom end of the chamber while the upper end of the chamber is filled from a manifold connected to an inflator.

According to a second aspect of the invention there is provided a motor vehicle having at least one curtain airbag assembly constructed in accordance with said first aspect of the invention.

The invention will now be described by way of example with reference to the accompanying drawing of which:-Fig.l is a partial side view of a right hand side of a motor vehicle having a curtain airbag assembly according to the invention showing the airbag assembly in a stowed state prior to deployment; Fig.2 is a view similar to Fig.i but showing an airbag forming part of the airbag assembly in a deployed state; Fig.3 is an enlarged view of an inflator and manifold forming part of the airbag assembly; Fig.4 is a scrap cross-section along the line x-x on Fig.2 through a deployment tube forming part of the airbag showing the deployment tube in a fully inflated condition; and Fig.5 is a scrap side view of the high pressure deployment tube shown in Fig.4 at the commencement of inflation.

With reference to Fig.1 there is shown part of the right hand side of a motor vehicle 5 as viewed from a passenger compartment of the motor vehicle 5. The motor vehicle 5 has a body structure 6 including a side wall 6W having three structural members in the fcrm of an A-post BA, a B-post 8B and a C-post BC. The side wall 6W has two window apertures 7A and 7B formed therein. A storage compartment B for a curtain airbag 30 is disposed at the top of the side wall 6W for stowing the curtain airbag 30 prior to deployment.

Referring now to Figs. 2 to 5 the curtain airbag 30 has an upper edge 36, a lower edge 37, a front edge 38 and a rear edge 39. When deployed the curtain airbag 30 has a width "W" and a length "L" (as shown on Fig.2) The curtain airbag 30 includes first and second inflatable chambers 31, 32 and first, second and third deployment tubes 33, 34 and 35. The deployment tubes 33, 34, 35 are formed as an integral part of the curtain airbag and are defined by columns of stitching 50 that sealingly separate the deployment tubes 33, 34, 35 from the inflatable chambers 31, 32. Fig.4 shows two columns of stitching 50 defining the third deployment tube 35 Each of the inflatable deployment tubes 33, 34, 35 is of a small internal volume compared to the two inflatable chambers 31, 32. In one example, the volume of each of the deployment tubes 33, 34, 35 was 2% of the volume of the inflatable chamber 31 and the inflatable chamber 32 was of substantially the same volume as the inflatable chamber 31.

It will however be appreciated that in other embodiments the two inflatable chambers 31, 32 could be of differing volume or there could be more or less than two inflatable chambers. However, in all cases, the volume of each deployment tube 33, 34, 35 is considerably smaller than any of the inflatable chambers of the curtain airbag thereby permitting it to be rapidly inflated during deployment of the curtain airbag 30.

Each of the deployment tubes 33, 34, 35 extends for substantially the entire length of the curtain airbag 30.

That is to say, each of the deployment tubes 33, 34, 35 extends from a position close to the upper edge 36 of the curtain airbag 30 to a position close to the lower edge 37 of the curtain airbag 30.

An inflator 21 is provided to inflate the curtain airbag 30 so as to deploy it. The inflator 21 is controlled by an electronic controller (not shown) in accordance with parameters stored in the controller and inputs received by the controller from sensors (not shown) located on the motor vehicle 5 as is well known in the art.

The inflator 21 is connected to a manifold 22 having a number of small cross-sectional area outlets 23, 24, 25, 26 and 27. Because of the very high pressure of circa 600 Bar developed in the inflator 21 the flow rate from the outlets 23, 24, 25, 26 and 27 is sufficient to produce the desired inflation but when the curtain airbag 30 is collapsing following the exhaustion of the inflator 21 the small cross-section area provides a significant resistance to flow of the relatively low pressure gas of circa 1.0 Bar from the inflatable chambers 31, 32. The provision of the small cross-sectional area outlets therefore acts as a virtual two way valve allowing flow during inflation and restricting flow during deflation. The outlets 23, 24, 25, 26 and 27 are connected to the two inflatable chambers 31, 32 and to the three deployment tubes 33, 34, 35 in the following manner.

The outlet 23 is connected to the first deployment tube 33 located near to the front edge 38 of the curtain airbag and is arranged to provide a gas flow "A" to the respective deployment tube 33 when the curtain airbag 30 is being deployed.

The outlet 24 is connected to the second deployment tube 34 located near to the rear edge 39 of the curtain airbag 30 and is arranged to provide a gas flow "D" to the respective deployment tube 33 when the curtain airbag 30 is being deployed.

The outlet 25 is connected to the third deployment tube located between the two Inflatable chambers 31, 32 and is arranged to provide a gas flow "F" to the respective deployment tube 35 when the curtain airbag 30 is being deployed.

The outlet 26 is connected to the first inflatable chamber 31 located towards the front of the curtain airbag 30 and is arranged to provide a gas flow "B" to the first chamber 31 when the curtain airbag 30 is being deployed.

The outlet 27 is connected to the second inflatable chamber 32 located towards the rear of the curtain airbag 30 and is arranged to provide a gas flow "C" to the second inflatable chamber 32 when the curtain airbag 30 is being deployed.

The cross-sectional area of the outlets 23 to 27 could be identical or they could of differing cross-sectional area so as to provide differing flow rates "A" to "F".

In Fig.5 the curtain alrbag 30 is showed in a rolled up stowed state just after inflation has commenced and the third deployment tube 35 is beginning to inflate. It will be appreciate that the curtain airbag 30 could be folded rather than being rolled up in its stowed state.

Operation of the airbag assembly is as follows, when the inflator 21 receives a command to inflate the curtain airbag 30 it begins to produce gas that flows into the manifold 22 and then out via the outlets 26, 27; 23, 24, 25 to the inflatable chambers 31, 32 and tc the deployment tubes 33, 34, 35 respectively. Because the deployment tubes 33, 34, 35 are of a small volume the initial gas flow will rapidly inflate them causing them to straighten from their stowed positions thereby pulling the rest of the curtain airbag 30 into position before the inflation of the inflatable chambers 31, 32 has completed. The gas continues to flow thereby inflating the inflatable chambers 31, 32 which have been correctly pre-positioned by the deployment tubes 33, 34, 35 to overlie the window apertures 7A, 7B.

Therefore, unlike a conventional curtain airbag, the time taken to locate the curtain airbag 30 in position is not determined by the time taken to fill the relatively large volume inflatable chambers 31, 32 but is dictated by the time taken to inflate the deployment tubes 33, 34, 35 which assist the deployment of the curtain airbag 30 by rapidly pulling it into position as they unfold.

One advantage of the invention is that a smaller inflator can be used compared to a conventional curtain airbag because the filling time of the two inflatable chambers 31, 32 does not determine the time taken to position the curtain airbag 30 unlike a conventional curtain airbag.

A further advantage can be obtained if the pressure in the deployment tubes 33, 34, 35 is arranged to remain high during the time period that the curtain airbag 30 is deployed. In such a case, the deployment tubes 33, 34, 35 act as stiffening members that can prevent undue distortion of the curtain airbag 30 and reduce the possibility of part of the curtain airbag being extruded out through one of the window apertures 7A, 7B. The deployment tubes 33, 34, 35 therefore are able to stabilise the curtain airbag 30 and help to maintain it in position.

Another advantageous arrangement is to provide one or more vents in one or more of the deployment tubes 33, 34, 35. The vent or vents (not shown) are located near to the lower edge 37 of the curtain airbag 30. As the deployment tubes 33, 34, 35 approach their fully deployed positions the unfolding or unrolling of the material forming the deployment tubes 33, 34, 35 reveals or uncovers the vent or vents thereby allowing gas to flow from the respective deployment tube 33, 34, 35 into an adjacent inflatable chamber 31, 32. This has the effect of increasing the speed of filling of the inflatable chambers 31, 32 after the curtain airbag 30 has been positioned by the initial filling of the deployment tubes 33, 34, 35. Such an arrangement allows the inflatable chambers 31, 32 to be filled from the top via the manifold 22 and the outlets 26, 27 and from the bottom via one or more vents in one or more of the deployment tubes 33, 34, 35. This is advantageous in that it is normally difficult to produce rapid inflation of the bottom of a curtain airbag and yet, in some cases, this is where initial contact of an occupant may occur.

Although the invention has been described with reference to an embodiment having two inflatable chambers it will be appreciated that it can be advantageously applied to curtain airbags having a different number of inflatable chambers. For example, in one embodiment the curtain airbag has a single inflatable chamber and two deployment tubes are used one at each end of the curtain airbag.

Although the invention has been described with reference to the use of depioyment tubes that are formed as an integral part of the curtain airbag it will be appreciated that the deployment tubes could be separate items that are fastened to the curtain airbag. This arrangement has the advantage that the invention could be potentially applied to an existing curtain airbag.

Therefore in summary the use of small volume inflatable tubes provides a cost effective way to position a curtain airbag more rapidly without the need for a large inflator and provides additional utility either by providing increased stiffness for the curtain airbag or by providing additional means for filling each main inflatable chamber of the curtain airbag.

It will be appreciated by those skilled in the art that although the invention has been described by way of example with reference to one or more embodiments it is not limited to the disclosed embodiments and that one or more modifications to the disclosed embodiments or alternative embodiments could be constructed without departing from the scope of the invention as set out in the appended claims.

Claims

-10 -Claims 1. A curtain airbag assembly for a motor vehicle having a curtain airbag securable along an upper edge to part of a body structure of the motor vehicle and an inflator to inflate the curtain airbag, the curtain airbag having at least one inflatable chamber arranged so as to extend when deployed in front of at least one window aperture of the motor vehicle to provide protection for an occupant of the motor vehicle, and at least one deployment tube formed as part of the airbag to assist with deployment of the airbag, wherein the at least one deployment tube is rapidly inflated during deployment of the curtain airbag so as to pull the curtain airbag guickly into position.
2. An assembly as claimed in claim 1 wherein the or each deployment tube extends along substantially the entire length of the airbag.
3. An assembly as claimed in claim 1 or in claim 2 wherein each deployment tube is of a small volume compared to the volume of an inflatable chamber thereby permitting it to be rapidly inflated.
4. An assembly as claimed in any of claims 1 to 3 wherein the at least one deployment tube is formed as an integral part of the airbag.
5. An assembly as claimed in any of claims 1 to 4 wherein the inflator is connected to the airbag via a manifold having separate outputs for the at least one chamber and the at least one deployment tube.
6. An assembly as claimed in any of claims 1 to 5 wherein the airbag has two Inflatable chambers and each of the chambers is bounded on both sides by a respective deployment tube.

-11 -
7. An assembly as claimed in claim 6 when dependent upon claim 5 wherein the manifold has a first outlet for supplying gas to a first deployment tube located at one end of the airbag, a second outlet for supplying gas to a second deployment tube located at an opposite end of the airbag, a third outlet for supplying gas to a third deployment tube located between the two inflatable chambers, a fourth outlet tube for supplying gas to one of the two inflatable chambers and a fifth outlet for supplying gas to the other of the twoinflatable chambers.
8. An assembly as claimed in any of claims 1 to 7 claim wherein at least one deployment tube includes one or more vents opened when the respective deployment tube is substantially fully inflated for supplying gas to at least one inflatable chamber.
9. An assembly as claimed in claim 8 wherein the one or more vents supply gas to a bottom end of the chamber while the upper end of the chamber is filled from a manifold connected to an inflator.
10. A motor vehicle having at least one curtain airbag assembly as claimed in any of claims 1 to 9.
11. A curtain airbag assembly substantially as described herein with reference to the accompanying drawing.
12. A motor vehicle substantially as described herein with reference to the accompanying drawing.