WO2013006128A1

WO2013006128A1 - Curtain airbag for a motor vehicle

Info

Publication number: WO2013006128A1
Application number: PCT/SE2012/050721
Authority: WO
Inventors: Robert Davis; Daniel RADOSAVLJEVIC; Justin LIM
Original assignee: Autoliv Development Ab
Priority date: 2011-07-06
Filing date: 2012-06-27
Publication date: 2013-01-10
Also published as: DE102011106794A1; DE102011106794B4

Abstract

The present invention relates to a curtain airbag (2) for a motor vehicle with a main chamber (9), which is provided for attachment at the edge of a lateral upper roof edge (1) with a drawn down protrusion (4), wherein the curtain airbag (2) com- prises a chamber (6) at an area, which is provided for arrangement at the drawn down protrusion (4), which chamber (6) is arranged in a manner for stabilising the area bearing on the drawn down protrusion (4) by inflating previously to the inflation of the main chamber (9).

Description

Curtain airbag for a motor vehicle

The invention relates to a curtain airbag for a motor vehicle according to the features of claim 1.

Curtain airbags are in general used for the protection of pas^¬ sengers so that they do not impinge on the inner side struc^¬ ture of the motor vehicle or move outside through an opened window in case transverse acceleration occurs. The curtain airbags thereto comprise a relatively large surface with a length of ca. 1.5 to 2 m and a width of ca. 0.4 - 0.7 m in an inflated condition, and are wrapped to a long hose for a space saving attachment. The curtain airbag wrapped to a hose is then attached below the interior lining of the motor vehicle at the lateral upper roof edge and when activated primary to a fluidic connected gas generator is inflated to its full sur^¬ face and to its full volume respectively.

Since the curtain airbag has to be attached to the roof edge before inflation, in adverse circumstances it may be the case that the curtain airbag in a non inflated condition must be placed in a larger length because of a gradient given by the gradient of the roof edge than actually would be required for an optimal geometry in an inflated condition. In this case the curtain airbag does not comprise the required tension in lon^¬ gitudinal direction for keeping back the passengers during the inflation because of the larger length. This is in particular disadvantageous for the protection of the passenger against moving out of an opened window, because this protection can only be achieved effectively with a tense curtain airbag. One example of such a type of motor vehicle are e. g. sports cars, which do not comprise lateral B-columns between the front seats and the back seats, and at which intentionally the lower lateral roof edges are drawn down for establishing a larger bearing surface for the front and the back doors. Such a shape of the roof edges is in particular preferred for motor vehicles without B-Columns with front doors which are hooked at the front side and with back doors which are hooked at the back side.

It is an object of the invention to develop a curtain airbag, which can be attached at a lateral roof edge along a drawn down protrusion without thereby loosing its tension in lateral direction during inflation.

To solve this object it is proposed that the curtain airbag comprises a chamber in the area, which is provided for bearing on the drawn down protrusion, which chamber is arranged in a manner for stabilizing the area bearing on the drawn down protrusion by inflating previously to the inflation of the main chamber. The chamber intentionally provides a section of smaller volume, which is inflated first and is stabilising the curtain airbag in the area while the further inflation Because of the tensioning of the curtain airbag by the chamber the disadvantageous factor can be compensated according to which the curtain airbag actually comprises a length, which is too large, due to the gradient induced by the protrusion and thus would "sag".

Further it is proposed that the chamber comprises an inlet opening, which is arranged in gas flow direction of the gas flow generated by the gas generator upstream to an inlet opening of the main chamber. Due to the proposed arrangement of the inlet opening a part of the gas flow of the gas generator necessarily first is guided into the chamber before the re^¬ maining part is flowing into the main chamber of the curtain airbag. Further the chamber can be used to deflect the gas flow in a direction beneficial for inflating the main chamber.

Further it is proposed, that the chamber is designed in an L- shaped manner. By designing the chamber in an L-shape the curtain airbag is tensioned in two different directions arranged in an angle to each other which are preferably the inflation direction vertical downwards and in length direction of the curtain airbag.

Further it is proposed, that the main chamber is designed by at least two layers encompassing a hollow space in between each other, and that the chamber is delimited from the main chamber by a connecting line of the layers. Thus the chamber can be produced together with the production of the curtain airbag e. g. by sewing of the layers, whereby the costs for material and production can be reduced.

In the following the invention is explained by means of a pre^¬ ferred embodiment with reference to the accompanying figures. The figures show:

Fig. 1 and 2 curtain airbag according to the state of the art in the attached condition and during inflation; and

Fig. 3 and 4: curtain airbag with chamber in the extended condition and after inflation at the motor vehicle. In figure 1 a curtain airbag 2 wrapped up to a hose before the inflation is disclosed. The curtain airbag 2 is provided for attachment on a lateral upper roof edge 1, which comprises along its gradient a protrusion 4 extending downwards. The protrusion 4 can e. g. be used as an enlarged bearing surface for a door or can be given by the transversal section of a cross bar of a roof structure. In any case the protrusion 4 forms an area A, in which the curtain airbag 2 is installed along a curved gradient according to the shape of the protru^¬ sion 4, which means an extension of the curtain airbag 2. Further a gas generator 8 is provided at the curtain airbag 2, which produces the gas flow required for inflation of the cur^¬ tain airbag 2 when activated.

In figure 2 the same curtain airbag 2 is disclosed during in^¬ flation. The curtain airbag 2 is attached to the roof edge 1 and the adjacent roof structure 3 respectively by appropriate means for attachment by tensioning strips and attachment flaps 15 and 16. Due to the larger length of the curtain airbag 2 in the area of the protrusion 4 the curtain airbag 2 becomes slack in the area A during inflation, i.e. it looses the re^¬ quired tension in longitudinal direction between the attachment flaps and the tensioning strips 15 and 16. Virtually the curtain airbag 2 sags, whereby a passenger impinging laterally on the curtain airbag 2 in adverse circumstances can move out^¬ side through an opened window with its head and/or upper body.

For avoiding such drawback the enhanced curtain airbag 2 ac^¬ cording to the invention comprises a chamber 6 in the area A as disclosed in the figures 3 and 4. The chamber 6 is realised by a connecting seam 14 of two layers and a non inflated area 17 of a main chamber 9 and thus simultaneously is confined from the main chamber 9. The connecting seam 14 is arranged and dimensioned such, that the chamber 6 comprises the form of an "L", wherein one arm of the L is directed in inflation direction of the curtain airbag 2 downwards and one arm is di^¬ rected in length direction of the curtain airbag 2. The chamber 6 is provided with an inlet opening 11 which is arranged in gas flow direction of the gas flow 7 generated by the gas- generator 8 upstream to an inlet opening of the main chamber 9.

The gas flow 7 generated by the gas generator 8 is deflected first in a deflection section 10, which is provided by a tube with two outlet openings 12 and 13. The deflection section 10 and the chamber 6 are arranged excentric at the curtain airbag 2, due to the position of the protrusion 4. Due to this excentric arrangement of the deflection section 10 the outlet open^¬ ings 12 and 13 are dimensioned of different size, thus the main chamber 9 overall is inflated equally by the different and in this case contrary orientated gas flows 5 and 7. Of course the gas flows 5 and 7 entering the main chamber 9 from the outlet openings 12 and 13 can be directed through further channels such that the curtain airbag 2 in the inflated condi^¬ tion comprises a predefined geometry and unfolds according to a predetermined inflation characteristics.

By the arrangement of the proposed chamber 6 the curtain air- bag 2 in an early state is first inflated completely in the area A independently of its actual length, thus subsequently the curtain airbag 2 is tensioned during the complete infla^¬ tion process in longitudinal direction.

In the described example the chamber 6 is L-shaped and among other things causes a deflection of the gas flow generated by the gas generator 8 in the longitudinal direction of the cur- tain airbag 2. The longitudinal direction of the curtain air- bag 2 is due to the inner side surface of the motor vehicle to be covered orientated parallel to the longitudinal axis of the motor vehicle.

Claims

1. Curtain airbag (2) for a motor vehicle with a main chamber (9), which is provided for attachment at the edge of a lateral upper roof edge (1) with a drawn down protrusion (4), characterized in that the curtain airbag (2) com^¬ prises a chamber (6) at an area, which is provided for ar^¬ rangement at the drawn down protrusion (4), which chamber

(6) is arranged in a manner for stabilising the area bearing on the drawn down protrusion (4) by inflating previously to the inflation of the main chamber (9) .

2. Curtain airbag (2) according to claim 1, characterized in that, the chamber (6) comprises an inlet opening (11) which is arranged in gas flow direction of the gas flow

(7) generated by the gas generator (8) upstream to an inlet opening of the main chamber (9) .

3. Curtain airbag (2) according to one of the preceding

claims, characterized in that, the chamber (6) is designed in an L-shaped manner.

4. Curtain airbag (2) according to one of the preceding

claims, characterized in that, the main chamber (9) is de^¬ signed by at least two layers encompassing a hollow space in between each other, and the chamber (6) is delimited from the main chamber (9) by a connecting line (14) of the layers .