WO2008111881A1

WO2008111881A1 - An air-bag

Info

Publication number: WO2008111881A1
Application number: PCT/SE2007/000235
Authority: WO
Inventors: Adam Machnik; Remi Baillivet; Bruno Raffy
Original assignee: Autoliv Development Ab
Priority date: 2007-03-13
Filing date: 2007-03-13
Publication date: 2008-09-18

Abstract

An air-bag is disclosed which comprises a first panel (3) and a second panel (13). The two panels are attached to one another in order to define an interior volume located between the two panels. The arrangement is characterised by the first panel (3) having an integrated network of inflatable gas channels (10), and being provided with a gas inlet aperture (20) which is in fluid communication with the network of gas channels (10). The aperture (20) is configured to receive part of an inflator (22).

Description

Title: AN AIR-BAG

Description of Invention

THE PRESENT INVENTION relates to an air-bag and, more particularly, relates to an air-bag of the type intended to be inflated within the interior space of a motor vehicle in order to serve as a safety device in the event of an accident.

It is now very well known to provide the interior cabin of a motor vehicle with one or more inflatable air-bags to serve as safety devices, the or each air-bag being inflated in response to a signal received from a sensor indicative of an impending accident situation, so as to assume an inflated position in front of a seat occupant. Most modern motor vehicles are provided with at least two such inflatable air-bags, one being a driver's air-bag which is typically initially housed within the central hub of a steering wheel so as to inflate and adopt a position between the steering wheel and the driver of the motor vehicle, and the other being a passenger air-bag initially packed within a region of the dashboard in front of the front-seat passenger and configured to inflate so as to adopt a position between the dashboard and the front-seat passenger of the motor vehicle.

The present invention seeks to address problems which are a particular issue in connection with passenger air-bags, although it should be appreciated that the invention could also be implemented in a driver's air-bag or other air-bags provided elsewhere within the interior cabin of a motor vehicle.

A significant problem with conventional passenger air-bags is that they must be of significant size in order to provide effective restraint to a front-seat passenger in the event of an accident situation. It is common for front-seat passenger air-bags to have a volume of approximately 130 litres or even more. In order to inflate an air-bag of this significant size sufficiently quickly in order to provide protection in an accident situation, conventional air-bags of this type must be provided with large inflators having a sufficiently high output of inflating gas. Inflators of the size necessary for conventional front seat air-bags are heavy and expensive, both characteristics which are disadvantageous to a motor vehicle manufacturer. Motor vehicle designers nowadays are pressing for increasingly small and compact air-bag units, but small inflators are not normally capable of filling an air-bag of the size necessary to perform an effective restraint function for a front-seat passenger. It is therefore desirable to have an air-bag configuration which requires a significantly reduced volume of inflating gas in order to deploy the air-bag into a position to provide effective restraint to a front-seat passenger in the event of an accident situation.

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

Accordingly, the present invention provides an air-bag comprising a first panel and a second panel, the two panels being attached to one another to define an interior volume between the two panels, characterised by the first panel having an integrated network of inflatable gas-channels, and being provided with a gas inlet aperture in fluid communication with the network of gas-channels the aperture being configured to receive part of an inflator.

Preferably, the first panel is formed from two superimposed layers of sheet material attached to one another in selected areas by seams, the seams defining the network of gas-channels.

Advantageously, the layers of sheet material are fabric and the seams are formed as lines of stitching between the two layers. Conveniently, the first panel is formed using a one-piece weaving technique so as to have regions comprising two layers of fabric and regions of a single thickness of fabric defining seams, the seams defining the network of gas- channels. Layers of sheet material and are woven simultaneously via a one- piece-weaving technique such that the seams are formed integrally with the woven structure of the two layers.

Preferably, the second panel is formed from a single layer of sheet material.

Advantageously, the second panel is formed from a single sheet of fabric.

Conveniently, the first panel has a central-region and a pair of side-regions, the side-regions being folded so as to extend away from the central-region, and wherein a respective edge of the second panel is attached to an edge of each side-region of the first panel.

Preferably, each side-region has a substantially peripheral gas-channel defining a central area with no gas-channel.

Advantageously, the side-regions of the first panel are each substantially triangular in form, and extend away from the central-region so as to terminate with a corner remote from the central-region.

Conveniently, the second panel is generally "keyhole'-shaped when laid flat, having a substantially central waisted region, the waisted region serving to interconnect said corners of each side-region of the first panel.

Preferably, the air-bag has a generally geometrical form when the network of gas-channels are inflated, each corner of the form being defined by part of a gas-channel. Advantageously, at least one of said gas-channels is provided with at least one interior vent-hole configured to vent inflating gas from the gas-channel into the interior volume between the two panels.

Conveniently, the air-bag has at least one exterior vent-hole configured to vent gas from the interior volume between the two panels to the surrounding atmosphere and/or vice-versa.

Preferably, the or each exterior vent-hole is provided in the first panel, through a region of the panel not defining a gas-channel.

Advantageously, the or each exterior vent-hole is provided through a side- region of the first panel.

Conveniently, the or each exterior vent-hole is provided in the second panel.

So that the invention may be more readily understood, and so that further features thereof may be appreciated, an embodiment of 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 two layers of sheet material which are used to form a first panel of the air-bag of the present invention; FIGURE 2 is a perspective view showing the two layers illustrated in Figure 1 superimposed and attached to one another to define the first panel of the air- bag;

FIGURE 3 is a perspective view illustrating a second panel forming part of the air-bag;

FIGURE 4 is a perspective view illustrating an air-bag formed by joining together the first panel shown in Figure 2 and the second panel shown in Figure 3, the air-bag being viewed from below; FIGURE 5 is a perspective view showing the completed air-bag from above and one side;

FIGURE 6 is a side view illustrating the completed air-bag of Figure 5;

FIGURE 7 is a schematic illustration showing the manner in which an inflator is secured to the air-bag of Figures 4 to 6; and

FIGURE 8 is a schematic perspective view showing an air-bag in accordance with the present invention in its deployed position between a front-seat passenger and the dashboard of a motor vehicle.

Turning now to consider the invention in more detail, Figure 1 illustrates two layers of sheet fabric material which are used to form a first panel 3 (shown in Figure 2) of the air-bag. Each of the layers 1 , 2 is of substantially identical form, having a generally "butterfly" shape in which a pair of substantially triangular side-regions or "wings" 4 extend outwardly from a central region 5. The central region has a projecting "nose" or rounded region 6.

In order to form the first panel 3 illustrated in Figure 2, the two layers of fabric 1 ,2 are superimposed over one another so that their peripheral edges become substantially aligned, whereupon the peripheral edges of the two layers of fabric 1 ,2 are attached to one another to form a peripheral seam 7 running all of the way around the two layers of fabric 1 ,2.

The two superimposed layers of fabric 1 ,2 are also attached to one another by seams provided within the outer periphery of the panel. In particular, the superimposed side regions 4 of the layers are attached to one another by respective seams 8 which describe respective closed, generally triangular shapes. In a similar manner, the central regions 5 of the two layers 1 ,2 are also attached to one another by a seam 9 which describes a closed curvilinear shape. The seam 9 is provided generally between the two seams 8 and is spaced apart from the two seams 8. In one embodiment of the present invention, the seams 8, 9 which serve to attach the two layers 1 ,2 to one another in order to define the first panel 3, are formed as lines of stitching between the two fabric layers. However, in alternative embodiments of the invention, the two fabric layers 1,2 can be woven simultaneously, via a one-piece weaving technique such as that disclosed in WO90/09295, in which case the peripheral seam 7, the two triangular seams 8 and the curvilinear seam 9 will all be formed integrally with the woven structure of the two layers 1 ,2, thereby obviating the need for a separate stitching step in order to secure the two layers to one another.

Having particular regard to Figure 2, it should be noted that between the seams 7,8,9, a network of channels is defined (the channels being indicated generally by reference numeral 10 in Figure 2). The channels serve as gas- channels configured to receive a supply of inflating gas from an inflator such as a gas generator, as will be explained in more detail below.

In a preferred embodiment of the invention, at least one of the gas channels 10 can be provided with one or more vent holes 11. In the particular arrangement illustrated in Figure 2, three vent holes 11 are provided in the gas channel 10 which extends between the two side regions 4, above the curvilinear seam 9. These vent holes are provided through only one of the fabric sheets defining the first panel 3, and in the arrangement illustrated in Figure 2, the vent holes 11 are provided through the upper layer of fabric 2. In a manner described in more detail below, the vent holes 11 will be provided on the interior of the completed air-bag and serve to provide an internal venting function within the overall construction of the air-bag. The vent holes 11 can therefore be considered to represent interior vent holes.

Optionally, the first panel 3 may be provided with one or more further vent holes 12 which, in the completed air-bag, will perform a venting function from the interior of the air-bag to the surrounding atmosphere, and can hence be considered to represent exterior vent holes. In the arrangement illustrated in Figure 2, an exterior vent hole 12 is provided through both fabric layers 1 ,2, within the confines of each respective triangular seam 8. However, it should be noted that in variants of the invention, for example where the air-bag is made using a one-piece weaving technique, the region of the air-bag provided with the exterior vent hole 12 may comprise only a single thickness of fabric. Also, although not as preferred, further embodiments of the present invention may be provided with one or more exterior vent holes through the fabric 1 ,2 within the confines of the central curvilinear seam 9.

The precise function of the interior vent holes 11 and the exterior vent holes 12 will be described in more detail below.

Turning now to consider Figure 3, there is illustrated a second panel 13 of the air-bag which is defined by a single layer of sheet fabric material, having a generally "keyhole" shape which is rounded at one end 14, and which is substantially linear at the opposite end 15. The central region 16 of the second panel 13 is waisted so as to be narrower than the two end regions 14, 15. In a preferred embodiment, the second panel 13 is provided with at least one vent hole 17 which, in the completed air-bag, will serve a venting function from the interior of the air-bag to the surrounding atmosphere and hence can be considered to represent an exterior vent hole. The or each exterior vent hole 17 provided through the second panel 13 may be provided in addition to, or instead of, the exterior vent holes 12 formed through the first panel 3.

Turning now to consider Figure 4, the air-bag of the present invention is illustrated, with the first and second panels 3, 13 being attached to one another. In order to arrive at the configuration illustrated in Figure 4, the first panel 3, constructed as described above and as illustrated in Figure 2, is initially turned upside down from the position illustrated in Figure 2, so that the interior vent holes 11 formed in the gas channel 10 face downwardly. The second panel 13 is then laid over the central region 5 of the first panel 3 so that its linear edge 15 is aligned with the upper peripheral edge of the central region 5. These two edges are then secured to one another by conventional stitching, after which the side wings 4 of the first panel are folded upwardly so as to extend away from the central region 5 and so as to terminate with a corner 18 remote from the central region 5. The stitching securing the two panels together can then be extended such that the side edges of the second panel 13 are attached to the peripheral edges of the wings 4. In this manner, the resulting structure adopts a three-dimensional shape as illustrated in Figure 4, in which the second panel 13 serves to interconnect the two folded- up wing regions 4 of the first panel. In particular, it can be seen that the waisted region 16 of the second panel 13 serves to interconnect the two terminal corners 18 of the side wings 4.

The lines of stitching interconnecting the two panels are terminated at points 19 in the general region where the linear edges of the two wings 4 meet the curved edge of the rounded nose 6. It will therefore be appreciated that at this stage of the manufacture of the air-bag, the rounded end region 14 of the second panel 13 is generally superimposed over the rounded nose 6 of the first panel 3, but the two panels are not interconnected in this region. This allows the entire structure to then be turned inside-out, through the opening provided between the two rounded regions, so that the line of stitching interconnecting the two panels moves inside the air-bag.

After the air-bag has been turned inside-out as mentioned above, a further line of external stitching is then created in order to interconnect the peripheral edge pf the rounded part 14 of the first panel 13, and the peripheral edge of the rounded nose 6 of the first panel 3. This stitching will therefore remain on the exterior of the air-bag when completed, and serves to close the interior volume defined by the three-dimensional structure of the air-bag. It should also be appreciated that when the partially-stitched structure of the air-bag is turned inside-out, the interior vent holes 11 are moved to the interior of the air-bag so as to provide fluid communication between the network of gas channels 10 and the interior space created between the two panels 3, 13, The exterior vent holes, 12, 17 provide fluid communication between the interior space of the air-bag defined between the two panels 3,13 and the surrounding atmosphere.

Figure 5 illustrates the completed air-bag under gentle inflation for illustrative purposes so as to show the resulting shape of the air-bag. Figure 5 actually illustrates the air-bag as viewed from the front, and one side, and clearly shows the main frontal impact area (for impact by a vehicle occupant), having a generally triangular configuration, as defined by the region of the second panel 13 generally adjacent its linear edge 15. Running across the top of the frontal impact area is a gas channel 10 which is in free fluid communication with similar gas channels 10 running down each side of the generally triangular frontal impact area.

Figure 6 illustrates the completed air-bag, again under gentle inflation for illustrative purposes, from the side, with the frontal impact region mentioned above being illustrated on the left-hand side of the drawing. From here, it can be seen that each side of the air-bag also has a generally triangular form as defined by a respective "wing" 4 of the first panel 3. In particular, Figure 6 clearly shows that the sides of the air-bag are provided with a generally triangular configuration of gas channels 10. In more general terms, the overall structure of the air-bag can be considered to have a generally geometrical form when the network of gas channels are inflated (the gas channels being shown only lightly inflated in Figures 5 and 6), with each corner of the geometrical form being defined by part of a gas-channel 10. As also illustrated in Figure 6, the region of the resulting air-bag remote from the frontal impact area (i.e. the region to the right-hand side of the drawing) takes the form of a generally rounded nose or snout. The underside of this snout is provided with an inflator in a manner illustrated schematically in Figure 7.

As can be seen in Figure 7, an air inlet aperture 20 is formed in the rounded end part of the second panel 13, the inlet aperture 20 being substantially aligned with an identical air inlet aperture 21 formed through the first layer of sheet fabric 1 of the first panel 3. Part of an inflator 22 is then inserted through the aligned inlet apertures 20, 21 and is secured in position by a clamping ring 23 in a manner generally known per se, such that the second panel 13 and the first sheet layer 1 of the first panel 3 are clamped together between a mounting flange 24 provided around the inflator 22 and a clamping flange 25 provided on the clamping ring 23. The inflator 22 therefore extends into the gas channel 10 formed between the two layers 1 ,2 of the first panel 3 in the rounded region of the air-bag.

Figure 8 is a perspective view, from behind, and one side, showing a front seat passenger 26 in a conventional sitting position, with the air-bag of the present invention deployed between the passenger 26 and the dashboard 27 of the motor vehicle.

Upon receipt of an appropriate actuation signal, for example from a crash sensor mounted within the motor vehicle, the inflator 22 is actuated and injects a high pressure volume of gas into the gas channel 10 located in the region of the rounded front part of the air-bag. The inflating gas is thus driven under pressure into the network of gas channels 10 defined between the two fabric layers 1 ,2 of the first panel 3. The gas channels 10 are thus caused to inflate until they become substantially rigid, thereby serving to unfold the air-bag from its initial position in which it is tightly packed within the unit provided in the dashboard 27, so as to adopt its substantially fully inflated position illustrated in Figure 8. As will be appreciated, the inflatable volume of the network of gas channels 10 is small in comparison to the overall volume of the resulting inflated air-bag and so, in this manner, a relatively large air-bag can be fully deployed by using only a relatively small volume of inflating gas.

As the network of gas channels 10 are inflated, such that the air-bag is caused to fold out, the exterior vent holes 12, 17 serve to allow the flow of atmospheric air within the cabin of the motor vehicle, into the interior volume of the air-bag, so as to avoid the creation of any significant vacuum within the interior volume of the air-bag (that is the space between the two panels 3,13), which would otherwise inhibit free deployment of the air-bag. In preferred embodiments, each exterior vent hole 12, 17 is provided with a one-way valve configured to allow the flow of air within the cabin into the interior volume of the air-bag, but to prevent the flow of inflating gas out of the air-bag. Arrangements of this kind can provide increased restraint performance in some applications. It is preferred that the or each one-way valve takes the form of a simple flap-valve comprising a flap of fabric material covering the vent hole on the inside of the air-bag, but only secured to the air-bag along part of its periphery to allow the flap to bend away from the vent hole to allow the inflow of air. Preferably, there are two such vent holes, each having a diameter of at least 200mm.

In order to provide an appropriate restraining function, the air-bag should be allowed to absorb an impact from the passenger 26. The interior vent holes 11 thus serve to allow the venting of inflating gas from within the network of gas channels 10, into the interior volume of the air-bag (as defined between the two panels 3,13) as the passenger 26 impacts with the air-bag, thereby deforming the skeletal structure defined by the inflated network of gas channels 10. From here, the inflating gas can also be vented from the interior space, through the exterior vent holes 12, 17 into the surrounding atmosphere if necessary. In summary, therefore, it should be appreciated that the above-described invention provides an air-bag having a simple construction with a relatively small inflatable volume (as defined by the network of gas channels 10) which, when fully inflated, serves rather like a skeletal frame in order to support a relatively large overall air-bag having a larger interior volume. This allows a relatively small inflator, producing only a relatively low volume of gas, to be used with a relatively large air-bag, without sacrificing any speed of deployment.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. An air-bag comprising a first panel (3) and a second panel (13), the two panels being attached to one another to define an interior volume between the two panels, characterised by the first panel (3) having an integrated network of inflatable gas-channels (10), and being provided with a gas inlet aperture (20) in fluid communication with the network of gas-channels (10), the aperture (20) being configured to receive part of an inflator (22).

2. An air-bag according to claim 1 , wherein the first panel (3) is formed from two superimposed layers (1 ,2) of sheet material attached to one another in selected areas by seams (7,8,9), the seams defining the network of gas-channels (10).

3. An air-bag according to claim 2, wherein the layers (1 ,2) of sheet material are fabric and the seams (7,8,9) are formed as lines of stitching between the two layers.

4. An air-bag according to claim 1 , wherein the first panel (3) is formed using a one-piece weaving technique so as to have regions comprising two layers (1 ,2) of fabric and regions of a single thickness of fabric defining seams (7,8,9), the seams (7,8,9) defining the network of gas-channels.

5. An air-bag according to any preceding claim, wherein the second panel (13) is formed from a single layer of sheet material.

6. An air-bag according to any preceding claim, wherein the second panel (13) is formed from a single sheet of fabric.

7. An air-bag according to any preceding claim, wherein the first panel

(3) has a central-region (5) and a pair of side-regions (4), the side- regions (4) being folded so as to extend away from the central-region (5), and wherein a respective edge of the second panel (13) is attached to an edge of each side-region (4) of the first panel (3).

8. An air-bag according to claim 7, wherein each side-region (4) has a substantially peripheral gas-channel (10) defining a central area with no gas-channel.

9. An air-bag according to claim 7 or claim 8, wherein the side-regions

(4) of the first panel (3) are each substantially triangular in form, and extend away from the central-region (5) so as to terminate with a corner (18) remote from the central-region (5).

10. An air-bag according to claim 9, wherein the second panel (13) is generally "keyhole"-shaped when laid flat, having a substantially central waisted region (16), the waisted region serving to interconnect said corners (18) of each side-region (4) of the first panel.

11. An air-bag according to any preceding claim, having a generally geometrical form when the network of gas-channels (10) are inflated, each corner of the form being defined by part of a gas-channel (10).

12. An air-bag according to any preceding claim, wherein at least one of said gas-channels (10) is provided with at least one interior vent-hole (11) configured to vent inflating gas from the gas-channel (10) into the interior volume between the two panels (3,13).

13. An air-bag according to any-preceding claim, having at least one exterior vent-hole (12,17) configured to vent gas from the interior volume between the two panels (3,13) to the surrounding atmosphere and/or wee-versa.

14. An air-bag according to claim 13, wherein the or each exterior vent- hole (12) is provided in the first panel (3), through a region of the panel not defining a gas-channel.

15. An air-bag according to claim 14 as dependent upon any one of claims 7, 8, or 9, wherein the or each exterior vent-hole (12) is provided through a side-region (4) of the first panel (3).

16. An air-bag according to claim 13, wherein the or each exterior vent- hole (17) is provided in the second panel (13).