GB2319751A

GB2319751A - Airbag arrangement

Info

Publication number: GB2319751A
Application number: GB9624364A
Authority: GB
Inventors: Alois Juchem
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 1996-11-22
Filing date: 1996-11-22
Publication date: 1998-06-03
Anticipated expiration: 2016-11-22
Also published as: WO1998022313A1; GB2319751B; GB9624364D0; GB2354746A; DE19782127B4; GB2354746B; GB0030055D0; DE19782127T1

Abstract

An airbag arrangement comprises an airbag 19 including a plurality of parallel cells 21, a gas generator (15 figure 2) and means to direct the gas from the generator to an elongate gas duct 17 which supplies gas to the plurality of cells. The cells may be defined by seams 22 which may be stitched or woven between the two layers of the airbag. The gas duct may have a plurality of apertures 23 to direct the gas flow into the cells. The gas duct may be non-linear and may lie along the A post and roof rail above the door of a motor vehicle such that the airbag provides side-impact protection. A plurality of fixings 2, 3 and 4 may secure the airbag arrangement to the vehicle. A diffuser 10 may receive the gas generator and direct gas therefrom to the gas duct. Clamping means (18 figure 2) may secure the diffuser to the gas duct and similarly may secure the airbag to the diffuser. The arrangement may be contained within a housing (1 figure 1).

Description

DESCRIPTION OF INVENTION "IMPROVEMENTS IN OR RELATING TO AN AIR-BAG ARRANGEMENT" THE PRESENT INVENTION relates to an air-bag arrangement for use in a motor vehicle such as a motor car. In particular, the present invention relates to an air-bag arrangement of the type intended to provide a "side curtain" between the driver or occupant of a motor car and the immediately adjacent door and window.

It has been proposed to provide an air-bag in a motor vehicle which, when inflated, forms a substantially flat "curtain" located between the driver or occupant of the vehicle and the adjacent window or door. The air-bag, when inflated, extends across a substantial proportion of the area of the window, and thus provides a significant degree of protection in the event that a side impact should occur. The inflated air-bag also serves to minimise any risk that the head of the driver or occupant of the vehicle may pass through the window in an accident situation.

Although various designs have been proposed previously, it has been thought appropriate for the airbag, when in the uninflated state, to be stored in or adjacent the "A" -post and the roof immediately above the door opening. The air-bag is thus initially stored, in the uninflated state, in a relatively long small dimension cavity. A gas generator is provided at one end of the airbag and is adapted to inflate the air-bag in the event that an accident should arise.

It has been found that the gas from the gas generator initially passes through a portion of the air-bag that defines a conduit that extends from one end of the cavity in which the air-bag is initially stored to the other end of the cavity. The gas may travel with substantial velocity and may even damage the part of the air-bag which is initially located at the far end of said cavity.

Subsequently, the main operative part of the airbag is inflated, but problems can arise in the regions where the flow of gas changes from a flow that is extending substantially axially of the cavity to a flow that is directed to inflate the bag.

If an air-bag is to provide any realistic protection to the driver of, or other occupant of, a motor vehicle, the air-bag must be inflated within a very small period of time, typically 10 ms or less.

If attempts are made to increase the rate at which an air-bag inflates by increasing the pressure of gas supplied to the air-bag, there is a risk that the seams of the air-bag may be damaged. Also, if any over-large quantity of gas is injected into an air-bag, there is a risk that the air-bag will be over-inflated and may burst.

The present invention seeks to provide an improved air-bag arrangement.

According to this invention there is provided an air-bag arrangement adapted to be used in a motor vehicle, the air-bag arrangement comprising an air-bag which, when inflated, defines a plurality of substantially parallel cells, a gas generator and means to direct gas from the gas generator to an elongate gas duct, the gas duct being nonlinear, the gas duct being adapted to supply gas to said plurality of substantially parallel cells, the air-bag arrangement being provided with a plurality of fixing means to enable the arrangement to be fixed to a motor vehicle in such a way that said gas duct is held securely in position.

Preferably a gas diffuser is provided adapted to receive a gas generator and direct gas from the gas generator to said gas duct.

Conveniently the gas diffuser is provided with at least one means to fix the gas diffuser in position.

Advantageously the gas diffuser is provided with two means to fix the gas diffuser in position.

In a preferred embodiment one of said fixing means which fix the gas diffuser in position comprises clamping means adapted clampingly to secure the said diffuser to said gas duct.

Conveniently said clamping means also serve to secure part of the air-bag to the gas diffuser.

Advantageously the gas duct is provided with a plurality of apertures, the apertures being located to direct a flow of gas from the gas duct into the said cells.

Conveniently the gas diffuser, gas duct and air-bag are contained within a housing.

Advantageously the housing incorporates a yieldable padding between the outer part of the housing and the gas duct and air-bag.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which FIGURE 1 is a perspective view of an air-bag unit in accordance with the present invention, illustrating the fixing means that form part of the unit, and illustrating, in phantom, a motor vehicle in which the unit may be fitted, FIGURE 2 is a view corresponding to part of Figure 1, illustrating the gas generator, FIGURE 3 is a view illustrating part of the unit of Figure 1, showing a fixing point, FIGURE 4 is a cross-sectional view at an intermediate point on the unit, FIGURE 5 is a view illustrating the air-bag in the fully inflated state, FIGURE 6 is a cross-sectional view corresponding to Figure 4 of an alternative embodiment of the invention.

Referring initially to Figure 1 of the accompanying drawings, an air-bag unit in accordance with the invention is intended to be mounted within a motor vehicle. The airbag unit comprises an elongate housing 1 provided with first fixing means 2 at one end thereof, and second fixing means 3 at the other end thereof. An intermediate fixing means 4 is provided at an intermediate point.

The housing 1 comprises two substantially linear portions 5,6 connected by curved region 7. The housing 1 is so configured that it can be located in position in a motor vehicle, with one straight region 5 located on the "A"-post 8 of the vehicle and the other straight region 6 located above the door opening 9 of the motor vehicle. As shown in Figure 1, the air-bag unit may thus be readily mounted in position in a motor vehicle in an unobtrusive manner.

Referring now to Figure 2 of the accompanying drawings, at one end of the housing 1, the fixing means 2 are connected to a gas diffuser 10. The gas diffuser 10 defines a substantially cylindrical outer wall 11. The fixing means 2 are connected to the outer wall 11. At the end closest to the fixing means, the cylindrical outer wall 11 is provided with a transversely extending end wall 12. The end wall 11, however, defines a central aperture 13 which communicates with an axially extending cylindrical space located within the diffuser. This space is defined by a perforated wall 14. The space is dimensioned and adapted to receive a substantially cylindrical gas generator 15 in such a way that gas generated by the gas generator may pass through the perforations in the perforated wall. Appropriate means are provided for securing the gas generator 15 in position.

At the other end of the diffuser 10, the outer wall 11 converges to form an outlet port 16. The outlet port is connected to an elongate tubular gas duct 17. The gas duct 17 extends substantially the entire length of the housing 1. As will become clear the gas duct is nonlinear, since it has an overall configuration corresponding to that of the housing 1, incorporating a curved region.

The gas duct 17 is sealingly connected to the outlet port 16 of the diffuser by means of a clamping ring 18.

The mouth of an air-bag 19, as will be described below in greater detail, is also clamped by the clamping ring 18 around the exterior of the outlet port 16. The clamping ring 18 is connected to the intermediate fixing means 4 of the air-bag unit.

The air-bag 19 surrounds the gas duct and is initially in a folded state. At the far end of the housing 1, as can be seen in Figure 3, a further clamping ring 20 is provided, this clamping ring serving to clampingly engage the free end of the gas supply duct 17.

A part of the air-bag 19 may be clamped against the far end of the gas supply duct by the clamping ring. The clamping ring forms part of the second fixing means 3. The described arrangement enables the free end of the gas supply duct to be retained in position by a clamping means that is formed integrally with the second fixing means 3.

Thus the free end of the gas supply duct is held firmly in position when the air-bag unit has been mounted in a motor vehicle.

As can be seen in Figure 4, the air-bag 19 is stored within the housing 1 in a folded state, with a substantial proportion of the air-bag being located to the lower side of the gas distribution duct.

Figure 5 illustrates the air-bag 19 when inflated.

It can be seen that the air-bag is defined into a plurality of parallel substantially vertically extending "cells" 21.

This is achieved by securing together the fabric forming the front part of the air-bag together with the fabric forming the rear part of the air-bag at selected points, to form substantially vertically extending seams 22. This can be accomplished by stitching or preferably by an appropriate weaving technique in which the threads used to weave the front layer of fabric that forms the air-bag and the threads used to weave the rear layer of fabric that forms the air-bag are woven together in selected regions to form seams, such as the seams 22.

As can be seen in Figure 5 the gas duct 17 that extends from the gas diffuser 10 extends over substantially the entire length of the housing 1. The gas duct 17 is provided with a plurality of apertures 23 each of which communicate with a separate cell 21 when the air-bag is inflated. The apertures 23 are provided to direct a flow of gas from the gas duct 17 into the cells 21.

It will thus be understood that as the air-bag is inflated, the gas generator generates gas. The gas passes through the perforated wall 14 into the space within the gas diffuser 10 and thus flows into the gas duct 17. The gas emerges through the apertures 23 in the gas duct 17 at points all the way along the gas duct at virtually the same instant. The gas thus commences the inflation of the individual cells 21 simultaneously. Thus, the whole airbag is inflated at virtually the same time, enabling the inflation process to be completed particularly rapidly.

The individual cells 21 provide the bag with the desired degree of rigidity, so that the bag can provide protection for the driver or occupant of the vehicle in the event that a side impact occurs, and also to prevent the head of the driver or occupant of the vehicle being thrown out through the window.

Figure 6 illustrates a modified embodiment of the invention which is very similar to the embodiment illustrated in Figures 1 to 4, save that within the housing 1, surrounding the air-bag, is a foam material 24.

The foam defines a cavity that accommodates the folded bag 19. The function of the foam material 24 is to provide protection for the head of the driver in a situation where the head of the driver may impact with the air-bag unit, but where the air-bag does not inflate. For example, if a vehicle in which the air-bag unit is fitted is travelling along an un-made road, and the vehicle drives over a pothole, the head of the driver may inadvertently strike the air-bag unit. The foam material is present to ensure that, should a situation like this arise, the head of the driver will not strike a hard element forming part of the air-bag unit, such as the gas duct.

The fixing means 2,3,4 serve to mount the unit in position in such a way that the gas duct is retained in position and will not tilt. The unit may be mounted in position at an advanced stage in the manufacture of the vehicle. The unit may be such that it can be mounted in position without the gas generator in the unit, with the gas generator being placed in the unit during the final stages of manufacture of the vehicle.

It is to be appreciated that the unit, as described, may easily be mounted in a motor vehicle and it is intended that the unit is mounted in such a position that the unit is visible. Thus, the unit may be provided with an outer cover 25 which is made of a suitable plastics material. The outer cover may have a pleasing appearance so that, when the unit is mounted in a motor vehicle in a position in which it is visible, it does not look obtrusive.

The cover 25 maybe provided with a split-line 26 in the form of a region of mechanical weakness, configured so that the cover will open easily when the air-bag is inflated.

It is to be appreciated that an air-bag unit accordance with the invention may be designed so that it can be easily mounted in a motor vehicle enabling motor vehicles to be designed which can be used with or without the unit. This gives the manufacturer a greater degree of flexibility when determining the equipment levels for various models within a single range which utilise a single body shell.

Claims

CLAIMS:

1. An air-bag arrangement adapted to be used in a motor vehicle, the air-bag arrangement comprising an airbag which, when inflated, defines a plurality of substantially parallel cells, a gas generator and means to direct gas from the gas generator to an elongate gas duct, the gas duct being non-linear, the gas duct being adapted to supply gas to said plurality of substantially parallel cells, the air-bag arrangement being provided with a plurality of fixing means to enable the arrangement to be fixed to a motor vehicle in such a way that said gas duct is held securely in position.

2. An arrangement according to Claim 1 wherein a gas diffuser is provided adapted to receive a gas generator and direct gas from the gas generator to said gas duct.

3. An arrangement according to Claim 2 wherein the gas diffuser is provided with at least one means to fix the gas diffuser in position.

4. An arrangement according to Claim 3 wherein the gas diffuser is provided with two means to fix the gas diffuser in position.

5. An arrangement according to Claim 4 wherein one of said fixing means which fix the gas diffuser in position comprises clamping means adapted clampingly to secure the said diffuser to said gas duct.

6. An arrangement according to Claim 5 wherein said clamping means also serve to secure part of the air-bag to the gas diffuser.

7. An arrangement according to any one of the preceding Claims wherein one of the said plurality of fixing means comprises means engaging the end of the gas distribution conduit remote from said gas generator.

8. An arrangement according to any one of the preceding Claims wherein the gas duct is provided with a plurality of apertures being located to direct a flow of gas from the gas duct into the said cells.

9. An arrangement according to any one of the preceding Claims wherein the gas diffuser, gas duct and air-bag are contained within a housing.

10. An arrangement according to Claim 7 wherein the housing incorporates a yieldable padding between the outer part of the housing and the gas duct and air-bag.

11. An air-bag arrangement substantially as herein described with reference to and as shown in Figures 1 to 5 of the accompanying drawings as modified by Figure 6.

11. An air-bag arrangement substantially as herein described with reference to and as shown in Figures 1 to 5 of the accompanying drawings.

12. An air-bag arrangement substantially as herein described with reference to and as shown in Figures 1 to 5 of the accompanying drawings as modified by Figure 6.

13. Any novel feature or combination of features disclosed herein.

Amendments to the claims have been filed as follows CLAIMS: 1. An air-bag arrangement adapted to be used in a motor car, the air-bag arrangement comprising an air-bag which, when inflated, is disposed between an occupant of the motor car and the side of the motor car and which defines a plurality of substantially parallel cells, the air-bag further comprising a gas generator and means to direct gas from the gas generator to an elongate gas duct, the gas duct being non-linear and provided with a plurality of apertures located to direct a flow of gas from the gas duct into the said cells, the air-bag arrangement being provided with a plurality of fixing means to enable the arrangement to be fixed to a motor vehicle in such a way that said gas duct is held securely in position.

2. An arrangement according to Claim 1 wherein a gas diffuser is provided adapted to receive the gas generator and direct gas from the gas generator to said gas duct.

3. An arrangement according to Claim 2 wherein the gas duct is provided with at least one means to fix the gas duct in position.

4. An arrangement according to Claim 3 wherein the gas duct is provided with two means to fix the gas duct in position.

5. An arrangement according to Claim 4 wherein one of said fixing means which fix the gas duct in position comprises clamping means adapted clampingly to secure the said gas duct to said diffuser.

7. An arrangement according to any one of the preceding Claims wherein one of the said plurality of fixing means comprises means engaging the end of the gas duct remote from said gas generator.

8. An arrangement according to any one of the preceding Claims wherein the gas diffuser, gas duct and air-bag are contained within a housing.

9. An arrangement according to Claim 8 wherein the housing incorporates a yieldable padding between the outer part of the housing and the gas duct and airbag.

10. An air-bag arrangement substantially as herein described with reference to and as shown in Figures 1 to 5 of the accompanying drawings.