WO2016064336A1

WO2016064336A1 - Airbag device

Info

Publication number: WO2016064336A1
Application number: PCT/SE2015/051122
Authority: WO
Inventors: Wojciech Gidzinski
Original assignee: Autoliv Development Ab
Priority date: 2014-10-24
Filing date: 2015-10-22
Publication date: 2016-04-28
Also published as: DE102014016124A1; DE102014016124B4

Abstract

An airbag device is described. This airbag device comprises an airbag enclosing at least one chamber with said chamber being enclosed by two layers and an edge area, and at least one tensioning strap (20) being sewn to a portion of the edge area by means of a seam. The tensioning strap (20) has a width (w) defining a first direction (Z) and the strap (20) extends from a chamber proximate end (22) in a second direction (X) being perpendicular to the first direction (Z). The seam (30) has a first section (31 ) extending into the first direction (Z) from a first end (31 a) to a second end (31 b), a second section (32) extending from the first end (31 a) of the first section (31 ) into a direction towards the middle of the tensioning strap (20) to a first distal end (32b), and a third section (33) extending from the second end (31 b) of the first section (31 ) into a direction to- wards the middle of the tensioning strap (20) to a second distal end (33b). In order to enhance the force necessary to break the seam, the two distal ends (32b, 33b) are connected to one another by means of sig-sag portion (40) of the seam (30).

Description

Airbag Device

Description The invention relates to an airbag device according to the preamble of claim 1 .

Especially in the field of so called curtain airbags but also in the field of pedestrian airbags, airbag devices are known which comprise an airbag which encloses at least one chamber and at least one tensioning strap being sewn to a portion of an edge area of the airbag by means of a seam. For the following description of the prior art reference is made to curtain airbag devices, but the described facts also apply to pedestrian airbag devices and other airbag devices comprising an airbag and a tensioning strap. As has already been stated, the airbag encloses at least one chamber with said chamber being enclosed by two layers and an edge area. In the case that the airbag is made from two initially separate layers these two layers are sewn, welded or glued to each other along the whole edge area. In the case that the airbag is made from a single piece, a part of said edge area is a fold. In case of so called one-piece-woven-airbags the two layers "start" from the edge area. The invention relates to all kinds of airbags.

For sewing the at least one tensioning strap to a portion of the edge area, usually a box-shaped seam with a cross inside is used, as is shown in Figure 4. If a seam of this kind is used in connection with a tensioning strap having a width of 25 mm, as is standard in many applications, a breaking force of above 3kN can be reached.

Due to the often limited packing space and in order to reduce weight, tensioning straps with a smaller width, especially less than 20 mm, are now required for some applications. Tests have shown that when using a standard seam design, as shown in Figure 4, with a tensioning strap with a width of for example 17mm, a breaking force of 3kN cannot be reached. So, the invention sets itself the task to provide an airbag device of the generic type in which the breaking force of the seam is enhanced, especially such that even if a strap with a width smaller than 25mm a breaking force of above 3kN can be reached.

This task is fulfilled by an airbag device according to claim 1 .

The inventive seam is basically comprised of two portions, namely a triangle- shaped portion with an open end, such that the triangle is not closed (open tri- angle portion), and a sig-sag portion adjoining the open triangle portion. The pattern of the inventive seam is more complex than the "box seam" of the prior art in geometrical terms, but the manufacture process is not more complex. It can be even less complex than the box seam of the prior art, since the inventive seam can be sewn in one piece, especially if the sig-sag portion is designed as defined in claim 4, namely being comprised of an upper section, a lower section and at least two V-shaped sections connecting the ends of the upper section and the lower section.

The triangle portion comprises a base of said triangle being denoted as first section. This first section of the seam extends parallel to the width of the tensioning strap in a first direction. It is preferred that the length of this first section exceeds the width of the tensioning strap, such that the first section extends over the longitudinal edges of the tensioning strap. Consequently the two legs of the triangle (denoted as second section and third section of the seam) each cross a longitudinal edge of the tensioning strap since it is preferred that the sig- sag portion is located completely inside the tensioning strap.

Further preferred embodiments follow from further sub-claims and from the preferred embodiment described now.

The invention will now be described in detail by means of a preferred embodiment in view of the figures. The figures show:

Figure 1 a schematic representation of a curtain airbag device,

Figure 2 the detail D1 of Figure 1 .

Figure 3 the detail D2 of Figure 2 and Figure 4 the prior art in a representation according to Figure 3.

The invention will now be described in view of a curtain airbag device, but it needs to be mentioned that the invention can also be applied to different kinds of airbag devices, especially pedestrian-airbag devices.

Figure 1 shows a schematic representation of a curtain airbag device. This curtain airbag device comprises a curtain airbag 10, mounting tabs 1 6, a gas generator unit 18 for inflating the curtain airbag 10, and two tensioning straps 20, 20'. The curtain airbag 10 has two layers which are joined in an edge area 14. So, the two layers and the edge area 14 enclose the chamber 12. The curtain airbag 10 shown can be made of two initially separate layers or by OPW weaving. In these cases the whole edge area forms a non-inflatable part of the curtain airbag having a certain width. It is also possible to fold the airbag from one single sheet, such that a section of the edge area is a fold (not shown). Such a fold does not define a non-inflatable part of the airbag according to the definitions chosen in this application.

The edge area has a car forward section 14a and a car rearward section 14b, both forming non-inflatable parts of the curtain airbag. To both, the car forward section and the car rearward section (meaning to non-inflatable parts of the curtain airbag) a tensioning strap 20, 20' is sewn. The portions to which the tensioning straps 20, 20' are sewn are relatively small compared to the total area of the edge area. Both tensioning straps 20, 20' and both seams 30, 30' can be of the same type (as is shown), but this is not necessary.

The Figures 4 shows a seam with which a tensioning strap (here the tensioning strap 20) is sewn to a portion of the edge area according to the prior art. One sees, that this seam is box-shaped with a cross connecting the edges of this box.

Figures 2 and 3 show a seam 30 connecting the tensioning strap 20 to a portion of the edge area 14 according to the invention: The tensioning strap 20 has a width w defining a first direction, also called Z-direction. The width w of the tensioning strap 20 can for example be less than 20 mm. The tensioning strap 20 extends from a chamber proximate end 22 into a second direction, which is perpendicular to the first direction. This second direction is also called the X- direction.

The seam 30 connecting the tensioning strap 20 with a portion of the edge area 14 of the curtain airbag 10 can be looked as being comprised of two portions, namely the open triangle portion 25 and a zig-sag portion 40 adjoining the open triangle portion 25. As one can easily see, the seam 30 of the preferred embodiment can be sewn in one piece.

The open triangle portion 25 is comprised of a first section 31 extending from a first end 31 a in the first direction (Z-direction) to the second end 31 b in a straight line. This first section 31 forms the base of the open triangle portion 25. The length of the first section 31 exceeds the width w of the tensioning strap 20, such that the first section 31 cuts both longitudinal edges 20a, 20b of the tensioning strap 20. From the first end 31 a of the first section 31 a second section 32 extends towards its distal end (called first distal end 32b). The term "distal" means that it is distal from the first section 31 . The first distal end 32b is positioned inside the tensioning strap 20, such that the second section 32 cuts the lower longitudinal edge 20a of the strap. A third section 33 is symmetrically arranged in relation to the second section 32. So, the second section 33 has a second distal end 33b. The first distal end 32b and the second distal end 33b are remote from each other, such that the first section, the second section 32 and the third section 33 form an open triangle with the first section 31 forming the base and the second section 32 and the third section 33 forming the legs.

The first distal end 32b and the second distal end 33b are connected by means of the zig-sag portion 40. This zig sag portion 40 comprises an upper section 42 and a lower section 44 both extending into the second direction (X-direction). The upper section 42 starts from the second distal end 33b of the third section 33 to its distal end called third distal end 42b. The lower section 44 starts from the first distal end 32b of the second section 32to its distal end called fourth distal end 44b. Of course, the terms "upper" and "lower" are somewhat arbitrary and relate to the deployed state of the curtain airbag. In case of a pedestrian airbag the upper and the lower section might be in the same horizontal plane but the terms "upper" and "lower" are chosen for the sake of linguistic simplicity. A first V-shaped section 46 connects the first distal end 32b and the second distal end 33b and thus also the proximate ends of the upper section and 42 and the lower section 44. A second V-shaped section 48 connect the distal ends of the upper section 42 and the lower section 44 (third distal end 42b and fourth distal end 44b). In order to have maximum connection strength between the strap and the respective portion of the edge area, it is preferred that the sig- sag portion 40 is located completely inside the tensioning strap 20, or to be more precisely in geometrical terms: Completely between the longitudinal edges 20a, 20b of the tensioning strap 20.

In an alternative design (not shown in the figures) at least one V-shaped section (in this case preferably both V-shaped sections) could be replaced by a shape being comprised of more than one V, for example two Vs, that is a W. As it is shown it is preferred that the zig-sag portion 40 is located on the chamber distal side of the open triangle portion 25 and thus on the chamber distal side of the first section 31 . In this case the terms "proximate" and "distal" can also be read as proximate and distal relative to the chamber 12. List of reference numbers

10 curtain airbag

12 chamber

14 edge area

16 mounting tab

18 gas generator unit

20 tensioning strap

20a,b longitudinal edges of the tensioning strap 22 chamber proximate end

25 open triangle portion

30 seam

31 first section

31 a first end

31 b second end

32 second section

32b first distal end

33 third section

33b second distal end

40 sig-sag portion

42 upper section

42b third distal end

44 lower section

44b fourth distal end

46 first V-shaped section

48 second V-shaped section

w width

Z first direction

X second direction

Claims

1 . Airbag device comprising:

an airbag (10) enclosing at least one chamber (12), said chamber (12) being enclosed by two layers and an edge area (14) and

at least one tensioning strap (20) being sewn to a portion of the edge area (14) by means of a seam (30),

wherein

the tensioning strap (20) has a width (w) defining a first direction (Z), the strap (20) extends from an chamber proximate end (22) in a second direction (X) being perpendicular to the first direction (Z),

and wherein

the seam (30)

has a first section (31 ) extending into the first direction (Z) from a first end

(31 a) to a second end (31 b),

a second section (32) extending from the first end (31 a) of the first section (31 ) into a direction towards the middle of the tensioning strap (20) to a first distal end (32b), and

a third section (33) extending from the second end (31 b) of the first section (31 ) into a direction towards the middle of the tensioning strap (20) to a second distal end (33b),

characterized in that the two distal ends (32b, 33b) are connected to one another by means of sig-sag portion (40) of the seam (30).

2. Airbag device according to claim 1 , characterized in that the first section (31 ) of the seam (30) is longer than the width (w) of the tensioning strap (20), such that the first section (31 ) of the seam (30) extends over the longitudinal edges (20a, 20b) of the tensioning strap (20).

3. Airbag device according to one of the preceding claims, characterized in that the sig-sag portion (40) is completely located inside the tensioning strap (20).

4. Airbag device according to one of the preceding claims, characterized in that the second section (32), the third section (33) and the sig-sag portion (40) of the seam (30) are located on the chamber distal side of the first section (31 ) of the seam (30).

5. Airbag device according to one of the preceding claims, characterized in that the sig-sag portion (40) is comprised of an upper section (42), a lower section (44) and at least two V-shaped sections (46, 48) connecting the ends of the upper section (42) and lower section (44).

6. Airbag device according to claim 5, characterized in that the upper section (42) and the lower section (44) extend parallel to each other in the second direction (X).

7. Airbag device according to claim 5 or claim 6, characterized in that exactly two V-shaped sections (46, 48) are present.

8. Airbag device according to one of the preceding claims, characterized in that the seam (30) is symmetrical in respect of the longitudinal axis of the tensioning strap (20).

9. Airbag device according to one of the preceding claims, characterized in that the width (w) of the tensioning strap (20) is less than 25mm, prefera- bly less than 20mm .

10. Airbag device according to one of the preceding claims, characterized in that the seam (30) is sewn in one piece.

1 1 . Airbag device according to one of the preceding claims, characterized in that the airbag is a curtain airbag or a pedestrian airbag. Airbag device according to one of the preceding claims, characterized that the portion of the edge area (14) to which the tensioning strap sewn is non-inflatable.