GB2482341A

GB2482341A - Curtain airbag for a motor vehicle

Info

Publication number: GB2482341A
Application number: GB1012867.6A
Authority: GB
Inventors: Barry Grindle
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2010-07-30
Filing date: 2010-07-30
Publication date: 2012-02-01
Also published as: GB201012867D0

Abstract

A curtain airbag assembly for a motor vehicle is disclosed in which a curtain airbag forming part of the airbag assembly is securable along an upper edge 18U to part of the vehicle body structure 6. An inflator to inflate the airbag is provided. The airbag is adapted to co-operate with an adjacent part of the motor vehicle when the curtain airbag 10 is deployed to overlie a window aperture 7. The airbag comprises two or more elongate inflatable chambers 14, 15, 16 and at least one integral tether 12 fastened to at least two 14, 16 of the inflatable chambers in order to reduce outward deflection of the curtain airbag. Preferably three inflatable chambers are provided so that the second chamber 15 acts as a wedge if a body part impacts against the curtain airbag 10 thereby reducing the risk of the curtain airbag being pushed out through the window aperture 7.

Description

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

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

It is a problem with such curtain airbags that, particularly if the window aperture is large, part of the curtain airbag itself can be pushed out through the window aperture by an impact from an occupant against the airbag thereby potentially allowing a body part of the occupant to extend through the window aperture It is an object of this invention to provide a curtain airbag for a motor vehicle that has an improved resistance to extrusion through a window aperture and thereby reduces the risk that a body part of an occupant of the motor vehicle can be forced out through a window aperture during an accident.

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, wherein the curtain airbag has two or more elongate inflatable chambers arranged in a side by side relationship so as to extend, when deployed, in front of a window aperture of the motor vehicle, and at least one integral tether fastened to at least two of the two or more of the inflatable chambers so as to reduce outward deflection of the curtain airbag if impacted against by a body part of an occupant of the motor vehicle during an accident.

The at least one integral tether may extend across the window aperture.

The at least one integral tether may be attached to adjacent chambers.

Alternatively, the at least one integral tether may be attached to alternating chambers.

The at least one integral tether may extend from near to one edge of the curtain airbag to near to an opposite edge of the curtain airbag.

Each of the at least two elongate inflatable chambers may have a longitudinal axis when inflated and the at least one tether may be arranged substantially normal to the longitudinal axes of the at least two elongate inflatable chambers.

Each longitudinal axis may be arranged substantially horizontal when the curtain airbag is deployed.

The curtain airbag may have first, second and third elongate inflatable chambers, the first elongate inflatable chamber may be arranged in a side by side relationship with respect to the second elongate inflatable chamber and the second elongate inflatable chamber may be arranged in a side by side relationship with respect to the third elongate inflatable chamber and the at least one tether may be fastened to the first and third elongate chambers.

The second elongate inflatable chamber may be positioned inboard of the first and second elongate

inflatable chambers.

The curtain airbag may adopt a positive bow when deployed due to the effect of the at least one integral tether.

There may be several integral tethers spaced apart across the width of the curtain airbag.

According to a second aspect of the invention there is provided a motor vehicle having at least one curtain airbaq 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.la is a partial side view of a left hand side of a motor vehicle that has been cut-away to show an outer surface of a curtain airbag according to the invention in a deployed state; Fig.lb is a partial side view of the same vehicle shown in Fig.la as viewed from an interior of the vehicle; Fig.2 is a cross-section along the line X-X on Fig.la showing the curtain airbag in a post deployment position before a load F' has been applied to it; Fig.3 is a cross-section along the line X-X on Fig.la showing the curtain airbag in a post deployment position after the load F' has been applied to it; Fig.4 is a cross-section similar to that shown in Fig.2 of a prior art curtain airbag showing the curtain airbag in a post deployment position before the load F' has been applied to it; and Fig.5 is a cross-section similar to that shown in Fig.3 of the prior art curtain airbag shown in Fig.4 in a post deployment position after the load F' has been applied to it.

With reference to Figs.la to 3 there is shown a preferred embodiment of a curtain airbag assembly 8 as fitted to a rear portion of the left hand side of a motor vehicle 5.

The curtain airbag assembly 8 is shown in a deployed state in which a curtain airbag 10 overlies a window aperture 7 (the window glass is not shown) The curtain airbag assembly 8 includes the curtain airbag 10 fastened along an upper edge 18U at spaced apart fixing points by means of fasteners 9 to part of a body structure 6 of the motor vehicle 5 and an inflator 50 to provide gas at pressure to inflate the curtain airbag 10.

The curtain airbag 10 is folded up and stowed adjacent the inflator 50 prior to deployment.

The curtain airbag 10 has a front edge 18F, a rear edqe 18R and a lower or bottom edge 18B and one or more and in this case first, second and third elongate inflatable chambers 14, 15, 16 used for reducing the force of impact if a body part of an occupant impacts against the curtain airbag 10 when the curtain airbag 10 is in the deployed state. An outer periphery of the curtain airbag 10 is not in this case inflatable but could be in other embodiments and has three apertures formed in it near to the upper edge 18U of the curtain airbag 10 forming fixing points for co-operation with the fastening means 9 used to fasten the curtain airbag 10 to the body structure 6.

The curtain airbag 10 further includes three spaced apart integral tethers 11, 12, 13 that are made from nylon webbing so as to be relatively inextensible when subject to forces in the order expected during use. The integral tethers 11, 12, 13 reduce outward bowing or deflection of the curtain airbag 10 as will be described in more detail hereinafter. The term integral tether' as meant herein means a tether that is used to connect or join parts of the curtain airbag 10 unlike a conventional tether that is fastened at one end to part of the motor vehicle and is connected at an opposite end to the curtain airbag.

It will be appreciated that a corresponding curtain airbag assembly will be fitted to the right hand side of the motor vehicle 5.

Referring now in particular to Figs. 2 and 3 the curtain airbag 10 adopts, when deployed but subject to no impact forces F', a positive bow indicated by the dotted line PB' on Fig.2 due to the effect of the three tethers 11, 12 and 13 which hold the first and third elongate inflatable chambers 14, 16 at a spacing that is less than the diameter of the second inflatable chamber 15. The first elongate inflatable chamber 14 is arranged in a side by side relationship with respect to the second elongate inflatable chamber 14 to which it is attached and the second elongate inflatable chamber 15 is arranged in a side by side relationship with respect to the third elongate inflatable chamber 16 to which it is attached.

Each of the elongate inflatable chambers 14, 15, 16 has a longitudinal axis extending along its length and each longitudinal axis is arranged substantially horizontal when the curtain airbag 10 is deployed so that the elongate inflatable chambers 14, 15, 16 extend across the width of the window aperture 7.

The non-inflatable portion of the curtain airbag 10 adjacent to the upper edge 18U overlies the body structure 6 defining the upper edge of the window aperture 7 and the non-inflatable portion of the curtain airbag 10 adjacent to the bottom edge 18B overlies the body structure 6 defining the lower edge of the window aperture 7.

The three integral tethers 11, 12 and 13 extend from positions at or near to the upper edge 18U of the curtain airbag 10 to positions at or near to the bottom edge 18B and are fastened to the non-inflatable portions of the curtain airbag 10 and to the first and third elongate inflatable chambers 14 and 16.

The three integral tethers 11, 12, 13 are located on an outer surface of the curtain airbag 10 facing the window aperture 7.

The positioning of the second elongate inflatable chamber 14 inboard of the other two elongate inflatable chambers 14, 16 allows the second elongate inflatable chamber 15 to act as a wedge or keystone' when a force F' is applied in an outward direction (as indicated by the arrow F on Fig.2) to an inner surface of the curtain airbaq 10 by a body part of an occupant of the motor vehicle 5 during an accident.

The effect of the second inflatable chamber 15 has two main effects when the force F' is applied, firstly, it urges the first and third elongate inflatable chambers 14 and 16 into firm engagement with the window aperture as indicated by the reaction arrows rl and r2 on Fig.3 and secondly, due to this spreading or separating effect of the first and second elongate inflatable chambers 14 and 16, it creates tension in the three integral tethers 11, 12, 13 thereby reducing outward deflection of these due to the application of the force F' and thereby reducing negative or outward bowing of the curtain airbag 10.

The effect of the two reaction forces rl and r2 is in effect to channel the applied force F' into the window aperture surround rather than cause it to urge the curtain airbag 10 to be extruded through the window aperture 7. In addition, because the three tethers 11, 12, 13 are interposed between the first and third airbags 14 and 16 and the window aperture surround and extend across the window aperture 7, the reaction forces rl, r2 clamp the integral tethers 11, 12, 13 to the body structure 6 thereby allowinq the integral tethers 11, 12, 13 to resist the tension force applied to it.

Although in the embodiment shown in Figs.la to 3 each of the integral tethers 11, 12, 13 is arranged substantially normal to the longitudinal axes of the three elongate inflatable chambers 14, 15, 16 it will be appreciated that this not be the case and there could be for example a different number of tether arranged at an angle to the longitudinal axes. For example there could be only two integral tethers arranged in a V-shaped configuration between the upper and bottom edges 18U and 18B of the curtain airbag 10 at an angle of, for example and without limitation, 45 degrees to the longitudinal axes of the elongate inflatable chambers 14, 15, 16.

As can be seen in Fig.3 when an outwardly directed force F' is applied negative bowing of the curtain airbag is restricted and reduced compared to an airbag curtain having no integral tethers due to the tension generated in the integral tethers 11, 12, 13. The integral tether 11, 12, 13 minimise the outward deflection of the curtain airbag 10 and minimise the risk of a body part passing through the window aperture 7 during an accident such a vehicle roll-over event.

It will be appreciated that the above referred to embodiment is a preferred embodiment and that the invention is not limited to such an embodiment for example, the wedging feature produced by the positioning and overlappinq of the second elongate chamber need not be used provided the integral tethers extend across the full width of the window aperture 7 and the outer elongate chambers 14, 16 are positioned and sized to engage with the window aperture surround so as to hold the tethers in position when an outward force is applied.

Similarly it is possible to use the wedging feature of the second elongate inflatable chamber but have tethers that only connect the first and second chambers together and do not extend to the opposite edges of the curtain airbag.

It will also be appreciated that the invention is not limited to the use of circular elongate inflatable chambers or to the use of three elongate inflatable chambers, other shapes and numbers of inflatable chamber are envisaged by the inventors. It will also be appreciated that the chambers could be arranged to extend vertically rather than horizontally.

Figs.4 and 5 show a prior art curtain airbag 110 having three elongate inflatable chambers 114, 115 and 116 attached to the body structure 6 SO as to overlie the window aperture 7.

The curtain airbag 110 is, as before, attached at an upper edge 118U by several fastening means 9 and has a bottom edge 118B that overlies a window aperture surround.

Because in this case no integral tethers are present the curtain airbag 110 can deflect outwardly as indicated by the chain dotted line NB indicating the negative bow of the airbag curtain produced by the applied force F' . Because the three chambers 114, 115, 116 are attached to one another the effect of the force F' is to pull the outer two chambers 14, 16 inwards once the central chamber 115 has passed outwardly of them thereby exacerbating the problem of retaining the curtain airbag 110 inboard of the window aperture 7.

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, wherein the curtain airbag has two or more elongate inflatable chambers arranged in a side by side relationship so as to extend when deployed in front of a window aperture of the motor vehicle, and at least one integral tether fastened to at least two of the two or more of the inflatable chambers so as to reduce outward deflection of the curtain airbag if impacted against by a body part of an occupant of the motor vehicle during an accident.
2. An assembly as claimed in claim 1, wherein the at least one integral tether extends across the window aperture.
3. An assembly as claimed in claim 2, wherein the at least one integral tether extends from near to one edge of the curtain airbag to near to an opposite edge of the curtain airbag.
4. An assembly as claimed in any of claims 1 to 3, wherein each of the at least two elongate inflatable chambers has a longitudinal axis when inflated and the at least one tether is arranged substantially normal to the longitudinal axes of the at least two elongate inflatable chambers.
5. An assembly as claimed in claim 4, wherein each longitudinal axis is arranged substantially horizontal when the curtain airbag is deployed.
6. An assembly as claimed in any of claims 1 to 5, wherein the curtain airbag has first, second and third -11 -elongate inflatable chambers, the first elongate inflatable chamber being arranged in a side by side relationship with respect to the second elongate inflatable chamber, the second elongate inflatable chamber being arranged in a side by side relationship with respect to the third elongate inflatable chamber, and the at least one tether being fastened to the first and third elongate chambers.
7. An assembly as claimed in claim 6, wherein the second elongate inflatable chamber is positioned inboard of the first and second elongate inflatable chambers.
8. An assembly as claimed in claim 7, wherein the curtain airbag adopts a positive bow when deployed due to the effect of the at least one integral tether.
9. An assembly as claimed in any of claims 1 to 7, wherein there are several integral tethers spaced apart across the width of the curtain airbag.
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 drawinq.
12. A motor vehicle substantially as described herein with reference to the accompanying drawing.