Inflatable airbag

Abstract

An inflatable airbag (10) for a motor vehicle is disclosed. The airbag (10) comprises a pair of overlapping fabric layers (11, 12) interconnected by a peripheral seam (13) extending around and defining a boundary (14) of a single inflatable chamber (15) between the layers (11, 12). The inflatable chamber (15) has an inlet region (20) including a fluid inlet (19) connected to an inflator (27). First and second circumferentially spaced regions (22, 23) of the peripheral seam (13) are secured to one another such that the inlet region (20) overlaps at least one other region (21) of the inflatable chamber (15), thereby inducing an inflated shape of the chamber (15) when the airbag (10) is inflated by a flow of gas from the inflator (27), the inflated shape being characterized by the at least one other region (21) of the inflatable chamber (15) being positioned adjacent the inflator (27) when the airbag (10) is inflated.

Description

Technical Field

[0001] This invention relates to inflatable airbags. More specifically, this invention relates to inflatable airbags for use in motor vehicle safety devices. Background Technology

[0002] It is now widely known to provide airbags in motor vehicles to protect vehicle occupants in the event of an accident, and more recently, airbags have been provided that are arranged to inflate over an area outside the vehicle to protect pedestrians in the event of a vehicle impact. Over the years, all types of airbags have become quite complex, and many now have specific and somewhat complex shapes determined by the airbag's specific function, the required inflation characteristics, and the shape and configuration to which it will be mounted or intended to be inflated or across the inflated portion of the vehicle. Such airbags were initially provided in the form of tightly folded and / or rolled-up packages housed within airbag modules installed in motor vehicles.

[0003] Typically, airbags are made of woven fabric and usually consist of two or more fabric layers interconnected by seams. In many cases, the fabric layers are woven separately and then sewn together to provide a seam, but in some cases, the layers may be adhesively bonded to form an adhesive seam, or thermally fused together to form a fusion seam. However, in some cases, two fabric layers may be woven simultaneously via a so-called single-piece weaving technique, where the yarns of one fabric layer interweave with the yarns of the other fabric layer in certain areas, thereby creating woven seams in those areas that are integrated with the weave of the airbag fabric.

[0004] Airbags typically have an inlet that is usually directly connected to the inflator (such as a gas generator), allowing inflatable gas to flow from the inflator to inflate the airbag. Such inflators are configured to produce a large volume and a strong flow of inflatable gas, and therefore the force exerted on the airbag area where the inlet is located can be very high. In some cases, this can make it difficult to achieve the desired inflation characteristics of the airbag when there are limitations on the possible location of the inflator. Additionally, where the inflator must be positioned very close to the passenger, the inflator can pose a risk of injury to the passenger; for example, through impact with the inflator in the event of a collision. The inflator can also become very hot during operation, which can pose a risk of combustion to passengers in close proximity to the inflator. Therefore, it has been found that for some airbag devices, it can be difficult to properly position the inflator to ensure correct inflation characteristics while simultaneously ensuring adequate protection for vehicle occupants in close proximity to the inflator from the risk of injury due to contact or impact with the inflator.

[0005] This invention was designed based on the above considerations. Summary of the Invention

[0006] According to a first aspect of the invention, an inflatable airbag for a motor vehicle is provided; the airbag includes a pair of overlapping fabric layers interconnected by a peripheral seam extending around and defining a boundary of a single inflatable chamber between the layers; the inflatable chamber has an inlet region including a fluid inlet connected to an inflator; the airbag is characterized in that first and second peripherally spaced regions of the peripheral seam are fixed to each other such that the inlet region overlaps with at least one other region of the inflatable chamber, thereby causing an inflation shape of the chamber when the airbag is inflated by a gas flow from the inflator, the inflation shape being characterized in that at least one of the other regions of the inflatable chamber is positioned adjacent to the inflator when the airbag is inflated.

[0007] Optionally, the inflatable shape is further characterized in that at least one of the other regions of the inflatable chamber abuts against the inflator when the airbag is inflated.

[0008] In some implementations, the inflatable shape optionally has a two-layer configuration, wherein the inlet area abuts against at least one of the other areas.

[0009] Conveniently, the pair of overlapping fabric layers includes an upper fabric layer and a lower fabric layer, and wherein the inlet region of the inflatable chamber overlaps with the other region such that when the airbag is inflated, the lower fabric layer of the inlet region abuts against the upper fabric layer of the other region.

[0010] Optionally, the first and second regions of the peripheral seam are fixed to each other such that the entrance region of the inflatable chamber overlaps with two other discrete regions of the inflatable chamber.

[0011] The entrance area of ​​the inflatable chamber covers the first and second areas of the peripheral seam.

[0012] According to a second aspect of the invention, an inflatable airbag for a motor vehicle is provided; the airbag includes a pair of overlapping fabric layers interconnected by a peripheral seam that extends around and defines a boundary of a single inflatable chamber between the layers; the airbag is characterized in that first and second peripherally spaced regions of the peripheral seam are fixed to each other, thereby causing an inflation shape of the chamber when the airbag is inflated, such that the peripheral seam follows a non-planar path.

[0013] In some embodiments of the second aspect of the invention, the first and second regions of the peripheral seam are spaced apart and fixed to each other such that the first region of the inflatable chamber overlaps with at least one other region of the inflatable chamber, thereby providing a two-layer inflation configuration to at least a portion of the inflatable chamber when the airbag is inflated.

[0014] Optionally, the first region of the inflatable chamber covers the first and second regions of the peripheral seam.

[0015] Conveniently, the first region of the inflatable chamber may define an entrance to the inflatable chamber, which is configured to engage with an inflator.

[0016] In some embodiments of the second aspect of the invention, the pair of overlapping fabric layers includes an upper fabric layer and a lower fabric layer, and the first region of the inflatable chamber overlaps with the other region such that when the airbag is inflated, the lower fabric layer of the first region abuts against the upper fabric layer of the other region.

[0017] Optionally, the first and second regions of the peripheral seam are fixed to each other such that the first region of the inflatable chamber overlaps with two other discrete regions of the inflatable chamber.

[0018] In embodiments of the first or second aspect of the invention, which have two discrete other regions of the inflatable chamber, those regions may have substantially the same shape and configuration.

[0019] In some embodiments of two aspects of the invention, the first region of the peripheral seam defines a portion of one of the discrete other regions of the inflatable chamber, the second region of the peripheral seam defines a portion of another discrete other region of the inflatable chamber, and wherein the two discrete other regions of the inflatable chamber are interconnected by being connected to each other through the first and second regions of the peripheral seam.

[0020] Optionally, the two discrete other regions of the inflatable chamber may be substantially mirror-symmetrical about the connection between the first and second regions of the peripheral seam.

[0021] According to embodiments of the first and second aspects of the invention, the peripheral seam can be configured such that the peripheral seam has an interconnect width, the fabric layers are interconnected across the interconnect width, and wherein the first and second regions of the peripheral seam are fixed to each other by a connection portion formed entirely within the interconnect width.

[0022] Optionally, the interconnect width varies along the peripheral seam and is larger in the first and second regions of the peripheral seam than elsewhere along the seam.

[0023] Alternatively, the interconnect width varies along the peripheral seam and is narrower in the first and second regions of the peripheral seam than along other parts of the seam.

[0024] The connection may include a stitch. Alternatively or additionally, the connection may include an adhesive, or may be formed by applying heat to fuse the first and second regions of the peripheral joint together. Alternatively or additionally, the connection may include one or more rivets or other mechanical fasteners to secure the first and second regions of the peripheral joint together.

[0025] Optionally, the first and second regions of the perimeter seam are secured to each other by stitching. Alternatively or otherwise, the first and second regions of the perimeter seam may be secured to each other by one or more rivets or other mechanical fasteners.

[0026] The first and second regions of the perimeter seam may overlap.

[0027] According to embodiments of the first and second aspects of the invention, each of the fabric layers can be configured such that each fabric layer is woven and comprises a plurality of yarns, at least some of the yarns of one fabric layer interlacing with at least some of the yarns of another fabric layer to define the peripheral seam, which is thus woven and integral with the structure of the layer. Attached Figure Description

[0028] To facilitate a clearer understanding of the invention and to recognize its further features, embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:

[0029] Figure 1 This is a top plan view of an airbag partially assembled according to both the first and second aspects of the present invention.

[0030] Figure 2 yes Figure 1 A top-view plan view of the airbag, showing the first entrance area of ​​the inflatable chamber, which overlaps with two other areas of the inflatable chamber;

[0031] Figure 3 yes Figure 2 A view of the airbag from below, which shows the two other areas of the inflatable chamber in more detail;

[0032] Figure 4 It is along Figure 2 A cross-sectional view taken from line VV in the middle;

[0033] Figure 5 This is a schematic perspective view showing the airbag combined with the inflator before inflation;

[0034] Figure 6 This is a top view showing the entrance area of ​​the inflatable chamber in an inflatable state; and

[0035] Figure 7 It is a perspective view showing the entrance area of ​​an inflatable chamber in an inflatable state. Detailed Implementation

[0036] Various aspects and embodiments of the invention will now be discussed with reference to the accompanying drawings. Further aspects and embodiments will be apparent to those skilled in the art.

[0037] The invention disclosed herein is suitable for implementation in a wide range of different types of airbags, such as driver airbags, front passenger airbags, rear passenger airbags, knee airbags, chest airbags, side airbags, inflatable side curtains, and pedestrian airbags designed to inflate a portion of the exterior of a motor vehicle to provide protection for pedestrians in the event of a collision with a motor vehicle.

[0038] exist Figure 1 The image shows a partially constructed airbag 10 according to the invention, which is shown in a deflated state and unfolded into a flat shape.

[0039] The airbag 10 is formed of two flexible fabric layers 11 and 12 having substantially the same shape. Layers 11 and 12 are... Figure 1 The upper layer 11 extends across the lower layer 12. The upper layer 11 and the lower layer 12 are interconnected by a peripheral joint 13 that extends around and defines the boundary 14 of a single inflatable chamber 15 between the two layers.

[0040] In a preferred embodiment of the invention, it is proposed that the interconnecting layers 11, 12 of the airbag 10 be woven simultaneously on a single loom via a so-called "single-piece weaving" technique, in which the yarns of one layer interweave with the yarns of another layer in specific areas to define a peripheral seam 13. In this embodiment, the resulting peripheral seam 13 is thus woven as an integral part of the two layers 11, 12 of the fabric, while these layers remain separated from each other within the boundary of the peripheral seam 13, thereby defining an inflatable chamber 15. Figure 1 As shown, the yarns of the two layers 11 and 12 can also be interwoven in other areas 16 to interconnect the two layers 11 and 12 within the boundary 14 of the peripheral seam 13. Figure 1In the airbag shown, other interlacing regions 16 define an internal seam array, thereby creating a series of generally parallel inflatable chambers 17 within the inflatable chamber 15 formed between layers 11 and 12.

[0041] However, it should be understood that while the airbag of the present invention is particularly suitable for manufacture via the single-piece weaving technique of the type described above, it is not limited to the use of this technique. In fact, other embodiments are contemplated, including the peripheral seam 13 and any desired internal seams (such as...). Figure 1 Those seams indicated in region 16 can be formed in other convenient ways that are obvious to those skilled in the art. For example, in some embodiments, it is contemplated that the fabric layers 11, 12 can be completely separated from each other to form individual sheets and subsequently interconnected by seams that can be formed by conventional sewing to interconnect the fabric layers 11, 12, and / or can be formed by using adhesives to bond the fabric layers 11, 12 together, or even by applying heat to fuse the fabric layers 11, 12 together.

[0042] exist Figure 1 In the illustrated embodiment, where the peripheral seam 13 is formed via the aforementioned single-piece weaving technique, it will be observed that the peripheral seam 13 has a transverse interconnection width w, across which the yarns of the two layers 11, 12 interweave to interconnect the layers 11, 12. As will be observed, the interconnection width w may vary slightly along the peripheral seam 13, such that some areas of the peripheral seam 13 are wider than other areas.

[0043] It will be observed that, Figure 1 In the case of the specific airbag 10 shown, the interconnecting fabric layers 11, 12 have a very approximately elongated rectangular shape. More specifically, this will be observed at one end ( Figure 1 At the left end of the structure, fabric layers 11 and 12 are each shaped to define centrally positioned, slightly L-shaped structures 11a and 12a, positioned between a pair of substantially identical projecting wings 11b and 12b. A peripheral seam 13 interconnects the two fabric layers 11 and 12 around their entire periphery, including the wings 11b and 12b and the L-shaped structures, thereby defining a fluid inlet 19 leading to the inflatable chamber 15, except along a shorter length of the aligned L-shaped structures 11a and 12a that remain unconnected. The aligned and interconnected L-shaped structures 11a and 12a of the two fabric layers 11 and 12 cooperate to define a first region 20 of the inflatable chamber 15, while the aligned and interconnected wings 11b and 12b of the two fabric layers 11 and 12 cooperate to define corresponding discrete wing regions 21 of the inflatable chamber 15. More specifically, a first region of the inflatable chamber 15 defines an inlet region of the inflatable chamber 15, which is configured for connection to an inflator, as will be described in more detail below.

[0044] exist Figure 1 The lieutenant general observed that a pair of wings 11b, 12b of the fabric layer are interconnected by a first straight region 22 of the peripheral seam 13, while another pair of wings 11b, 12b are interconnected by a second straight region 23 of the peripheral seam 13. The first straight region 22 and the second straight region 23 of the peripheral seam 13 may have equal lengths and each defines a portion of a corresponding wing region 21 of the inflatable chamber 15. It should be understood that the first region 22 and the second region 23 of the peripheral seam 13 are spaced apart from each other along the periphery; in this sense, they are each located at a correspondingly spaced position around the seam 13. Furthermore, it should be noted that... Figure 1 In the specific airbag configuration shown, the aforementioned first straight region 22 and second straight region 23 of the peripheral seam 13 each have a larger interconnect width w than elsewhere along the seam 13, such as the region with a relatively narrow interconnect width w along the side of the main central region of the inflatable chamber 15, as indicated by reference numeral 24. However, this is not considered an essential aspect of the invention, and in other embodiments, it is contemplated that the first straight region 22 and second straight region 23 of the peripheral seam 13 may have a smaller interconnect width w than elsewhere along the seam 13. For example, an embodiment is contemplated in which the interconnect width w of the peripheral seam 13 varies around the seam according to the distance from a reference point. Figure 1 An exemplary reference point X is shown, located approximately at the longitudinal center along the length of the airbag 10 along the peripheral seam 13, where the width of the airbag 10 is narrowest. It is envisioned that the interconnect width w will be larger in the region of the peripheral seam far from the reference point X than in the region of the peripheral seam near the reference point X. Embodiments are therefore possible, for example, in the case of particularly large airbags, where the region of the peripheral seam 13 far from the reference point X may have an interconnect width w that is substantially greater than the interconnect width of the first region 22 and the second region 23.

[0045] Now go to Figure 2 The diagram shows the airbag 10 following subsequent steps in its construction. Specifically, Figure 2 The illustration shows the airbag 10 after the two wing regions 21 of the inflatable chamber 15 have been manipulated and moved below the inlet region 20 such that the corresponding first straight region 22 and second straight region 23 of the peripheral seam 13 overlap each other. Figure 4The cross-sectional view most clearly shows the overlapping relationship of the first straight region 22 and the second straight region 23 of the peripheral seam 13. In this configuration, it will be observed that a portion of the inlet region 20 of the inflatable chamber 15 overlaps the top of a portion of each wing region 21. Furthermore, it should be noted that in this configuration, the two wing regions 21 of the inflatable chamber 15 do not flip or fold over themselves, and thus the lower fabric layer 12 of the inlet region 20 is positioned across the top of the upper fabric layer 11 of each wing region 21.

[0046] The overlapping first straight region 22 and second straight region 23 of the peripheral seam 13 are then fixed to each other. In a preferred embodiment, this is achieved by creating one or more suture lines 25 to form a connecting portion that interconnects the first region 22 and the second region 23 of the peripheral seam 13. This is in Figure 3 The figure most clearly shows the end region of the airbag 10 as viewed from below. The connection between the first region 22 and the second region 23 of the peripheral seam 13 also interconnects the two wing regions 21 of the inflatable chamber 15. However, it should be noted that in alternative embodiments, it is contemplated that the regions 22, 23 of the peripheral seam 13 can be secured to each other in other convenient ways that will be apparent to those skilled in the art. For example, in some embodiments, it is contemplated that the regions 22, 23 can be secured to each other by using an adhesive to bond the regions 22, 23 together, or even by using the application of heat to fuse them together. In other embodiments, it is contemplated that the regions 22, 23 can be secured to each other by using rivets or other such fasteners.

[0047] What needs to be understood here is that... Figure 3 A pair of optional mounting tabs 26 are shown for the airbag 10, which are in Figure 1 and Figure 2 Not shown in the diagram. Each mounting tab 26 protrudes outward from the corresponding wing region 21. The mounting tabs 26 may be configured to facilitate securing the airbag 10 to the structure of the motor vehicle. As will be understood, in other embodiments, the mounting tabs 26 may be located at other locations surrounding the airbag.

[0048] It is considered preferred that each stitch 25 that secures the first region 22 and the second region 23 of the peripheral seam 13 to each other is formed entirely within the interconnecting width w of the peripheral seams in those regions.

[0049] about Figure 2 It should be noted that, in the illustrated embodiment, the two wing regions 21 of the inflatable chamber 15 are substantially mirror-symmetrical about the connection formed by the suture 25 that interconnects the first region 22 and the second region 23 of the peripheral seam.

[0050] Now go to Figure 5The diagram shows a completed airbag 10 combined with an inflator 27, which can be, for example, a gas generator of a type known per se. The inflator 27 is elongated and generally cylindrical, and is connected to the fluid inlet 19 of the airbag 10 (by insertion through it), such that the majority of the length of the inflator is situated within the inlet region 20 of the inflatable chamber 15. A clamp 28 is arranged around a fabric near the inlet region 20 of the fluid inlet 19, thereby securing the inflator to the airbag 10. As those skilled in the art will understand, the inflator 27 includes a series of gas outlets thus positioned within the inlet region 20 of the inflatable chamber 15, while the exposed end of the inflator includes an electrical connector 29 for connection to a circuit, typically including a collision sensor and an electronic control unit, operable to detect the occurrence of an impact or collision and thus send an actuation signal to the inflator to actuate it. The actuation of the inflator effectively directs the flow of inflation gas into the inlet region 20 of the inflatable chamber 15. This inflation gas is then directed from the inlet region into the main region of the inflatable chamber 15 to inflate the airbag 10, and from the main region into the two wing regions 21, such as... Figure 5 The arrows in the image roughly indicate this.

[0051] Now go to Figure 6 and Figure 7 The airbag 10 is shown in an inflated state, indicating its shape and configuration after actuation of the inflator 27 and thus inflation of the inflatable chamber 15. As shown, the two inlet regions 20 and the two wing regions 21 are configured for inflation, wherein the fabric layers 11, 12 are pushed open by inflation gas from the inflator 27.

[0052] As will be understood, if the peripherally spaced regions 22, 23 of the peripheral seam 13 were not interconnected and fixed as described above (whereby the two wing regions 21 of the inflatable chamber 15 interconnect below the inlet region 20), the airbag 10 would naturally achieve a generally flat two-dimensional inflatable shape upon inflation, with the peripheral seam 13 following a generally planar path around the airbag 10. However, because the peripherally spaced regions 22, 23 of the peripheral seam 13 are actually interconnected and fixed to each other adjacent to the inlet region 21, the effect of their interconnection is to cause a three-dimensional inflatable shape of the inflatable chamber 15 upon airbag inflation, with the peripheral seam 13 instead following a non-planar path. This in Figure 7The most clearly shown diagram illustrates that the inlet region 20 of the inflatable chamber 15 abuts against the wing region 21 in its inflation configuration. This i) slightly pushes the wing region 21 downward, and II) slightly pushes the inlet region 20 upward, such that the area extending around the wing region 21 and defining its peripheral seam extends beyond the plane of the area extending around the inlet region 20 and defining its peripheral seam. The inflation shape of the inflatable chamber 15 thus achieves a two-layer configuration in the regions of the inflator 27, the inlet region 20, and the wing region 21, where the inflation shape of the inlet region 20 represents the upper layer, and the inflation shape of the wing region 21 represents the lower layer. Furthermore, because the inflatable inlet region 20 abuts against the inflatable wing region 21, the inlet region 20 can provide some support to the wing region 21, and vice versa.

[0053] from Figure 6 and Figure 7 It will also be understood that when the airbag 10 is inflated, the inlet region 20 of the inflatable chamber covers the interconnected first region 22 and second region 23 of the peripheral seam 13, and overlaps with the two wing regions 21 such that the lower fabric layer 12 of the inlet region 20 abuts against the upper fabric layer 11 of the wing region 21. Furthermore, referring to… Figure 5 It should also be understood that when the airbag 10 is inflated, one of the wing regions 21 of the inflatable chamber 15 will be inflated in a configuration in which the wing region is positioned adjacent to and against the inflator 27, thereby providing the possibility of supporting the inflator 27 and providing a cushioning effect to protect vehicle occupants (or pedestrians in the case of a pedestrian airbag) from the potentially harmful impact with the inflator 27 in an accident. The fact that the wing region 21 is positioned adjacent to the inflator 27 also provides some protection to passengers (or pedestrians) from the risk of combustion, as it helps to prevent contact with the inflator 27, which can become very hot when actuated.

[0054] Features disclosed in the foregoing specific embodiments, in the appended claims, or in the drawings, expressed in their particular form or according to means for performing the disclosed functions or methods or processes for obtaining the disclosed results, may, where appropriate, be used alone or in any combination of such features to implement the invention in various forms.

[0055] While the invention has been described in conjunction with the foregoing exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art upon presentation of this disclosure. Therefore, the exemplary embodiments of the invention set forth above are to be considered illustrative rather than restrictive. Various changes may be made to the described embodiments without departing from the scope of the invention.

[0056] To avoid any doubt, any theoretical explanations provided herein are intended to enhance the reader's understanding. The inventor does not wish to be bound by any of these theoretical explanations.

[0057] Any chapter headings used in this document are for organizational purposes only and should not be construed as limiting the subject matter.

[0058] Throughout this specification, including the following claims, unless the context otherwise requires, the words “have,” “comprise,” and “include,” and their variations (such as “having,” “comprises,” “comprising,” and “including”) will be understood to imply inclusion of the stated integer or step or group of integers or steps, but not to exclude any other integer or step or group of integers or steps. It must be noted that, as used in the specification and appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context explicitly specifies otherwise. Scope may be expressed herein as from “about” one specific value and / or to “about” another specific value. When such scope is expressed, another embodiment includes from one specific value and / or to another specific value. Similarly, when a value is expressed as an approximation using the antecedent “about,” it should be understood that the specific value forms another embodiment. The term “about” in relation to numerical values ​​is optional and means, for example, + / - 10%.

[0059] As used herein, the terms "preferred" and "ideally" refer to embodiments of the invention that provide certain benefits in some circumstances. However, it should be understood that other embodiments may also be preferred under the same or different circumstances. Therefore, the description of one or more preferred embodiments does not imply or suggest that other embodiments are useless, and is not intended to exclude other embodiments from the scope of this disclosure or from the scope of the claims.

Claims

1. An inflatable airbag (10) for a motor vehicle; said airbag (10) comprising a pair of overlapping fabric layers (11, 12) interconnected by a peripheral seam (13) surrounding said layers (11, 12). The boundary (14) of the individual inflatable chamber (15) between 12) extends and defines the boundary; the inflatable chamber (15) has an inlet region (20) including a fluid inlet (19) connected to the inflator (27); the airbag (10) is characterized in that the peripherally spaced first region (22) and second region (23) of the peripheral seam (13) are directly connected to each other and fixed to each other such that the inlet region (20) overlaps with at least one other region (21) of the inflatable chamber (15), thereby causing an inflation shape of the chamber (15) when the airbag (10) is inflated by a gas flow from the inflator (27), the inflation shape being characterized in that at least one of the other regions (21) of the inflatable chamber (15) is positioned adjacent to the inflator (27) when the airbag (10) is inflated.

2. The airbag (10) according to claim 1, wherein the inflatable shape is further characterized in that at least one of the other regions (21) of the inflatable chamber (15) abuts against the inflator (27) when the airbag (10) is inflated.

3. The airbag (10) according to claim 1 or 2, wherein the inflatable shape has a two-layer configuration, wherein the inlet region (20) abuts against at least one of the other regions (21).

4. The airbag (10) according to claim 1, wherein the pair of overlapping fabric layers (11, 12) comprises an upper fabric layer (11) and a lower fabric layer (12), and wherein the inlet region (20) of the inflatable chamber (15) overlaps with each of the other regions (21) such that when the airbag (10) is inflated, the lower fabric layer (12) of the inlet region (20) abuts against the upper fabric layer (11) of each of the other regions (21).

5. The airbag (10) according to claim 1, wherein the first region (22) and the second region (23) of the peripheral seam (13) are fixed to each other such that the entrance region (20) of the inflatable chamber (15) overlaps with two other discrete regions (21) of the inflatable chamber (15).

6. The airbag (10) according to claim 5, wherein the two discrete other regions (21) of the inflatable chamber (15) have substantially the same shape and configuration.

7. The airbag (10) according to claim 5 or claim 6, wherein the first region (22) of the peripheral seam (13) defines a portion of one of the discrete other regions (21) of the inflatable chamber (15), and the second region (23) of the peripheral seam (13) defines a portion of another discrete other region (21) of the inflatable chamber (15), and wherein the two discrete other regions (21) of the inflatable chamber (15) are interconnected by the first region (22) and the second region (23) of the peripheral seam (13).

8. The airbag (10) according to claim 7, wherein the two discrete other regions (21) of the inflatable chamber (15) are substantially mirror-symmetrical about the connection between the first region (22) and the second region (23) of the peripheral seam (13).

9. The airbag (10) according to claim 1, wherein the inlet region (20) of the inflatable chamber (15) covers the first region (22) and the second region (23) of the peripheral seam (13).

10. The airbag (10) according to claim 1, wherein the peripheral seam (13) has an interconnect width (w), the fabric layers (11, 12) are interconnected across the interconnect width (w), and wherein the first region (22) and the second region (23) of the peripheral seam (13) are directly connected to each other and fixed to each other by a connection portion formed entirely within the interconnect width (w).

11. The airbag (10) according to claim 10, wherein the interconnect width (w) varies along the peripheral seam (13) and is larger at the first region (22) and the second region (23) of the peripheral seam (13) than elsewhere along the seam (13).

12. The airbag (10) according to claim 10 or claim 11, wherein the connecting portion includes a suture (25).

13. The airbag (10) according to claim 1, wherein the first region (22) and the second region (23) of the peripheral seam (13) are fixed to each other by stitching (25).

14. The airbag (10) according to claim 1, wherein the first region (22) and the second region (23) of the peripheral seam (13) overlap.

15. The airbag (10) according to claim 1, wherein each of the fabric layers (11, 12) is woven and comprises a plurality of yarns, at least some of the yarns of one fabric layer (11) interlacing with at least some of the yarns of the other layer (12) to define the peripheral seam (13), the peripheral seam (13) being woven and integral with the structure of the layers (11, 12).

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