AIRBAG FABRIC

Abstract

An airbag fabric for an airbag comprises a mounting area (22) for mounting the airbag. The mounting area (22) includes a mounting hole (24), a load portion (26) which is adjacent to the mounting hole (24) in a load direction (B), and a transition portion (28) which is adjacent to the mounting hole (24) against the load direction (B). Furthermore, the load portion (26) and the transition portion (28) include different weaves. The fabric in the load portion (26) exhibits lower resistance to displacement than in the transition portion (28) so that a fiber bead forms of the fabric fibers of the load portion (26), which fiber bead is adjacent to the mounting hole (24) in the load direction (B), if bearing stress acts upon the mounting hole (24) in the load direction (B).

Claims

1-17. (canceled)

18. An airbag fabric for an airbag comprising a mounting area for mounting the airbag, wherein the mounting area includes a mounting hole, a load portion which is adjacent to the mounting hole in a load direction, and a transition portion with is adjacent to the mounting hole against the load direction, wherein the load portion and the transition portion include different weaves and the fabric in the load portion exhibits lower resistance to displacement than in the transition portion so that a fiber bead forms of the fabric fibers of the load portion, the fiber bead being adjacent to the mounting hole in the load direction, if bearing stress acts upon the mounting hole in the load direction.

19. The airbag fabric according to claim 18, wherein the weave of the load portion has a first knot density and the transition portion includes a weave having a second knot density, the first knot density being lower than the second knot density.

20. The airbag fabric according to claim 19, wherein the first knot density amounts to not more than 50%, specifically to not more than 34%, of the second knot density.

21. The airbag fabric according to claim 18, wherein the fabric of the load portion has a tear propagation resistance which amounts to at least 150%, specifically at least 200%, of the tear propagation resistance of the transition portion.

22. The airbag fabric according to claim 18, wherein the warp threads of the weave of the load portion extend perpendicularly or in parallel to the load direction.

23. The airbag fabric according to claim 18, wherein the weave of the load portion is a Panama weave.

24. The airbag fabric according to claim 18, wherein the transition portion merges into an airbag chamber portion which forms a wall of an inflatable chamber.

25. The airbag fabric according to claim 18, wherein the airbag fabric is a one-piece-woven fabric in which the threads of opposite walls of an inflatable chamber at the edge merge into a joint weave.

26. The airbag fabric according to claim 18, wherein the load portion is multi-layered, specifically two-layered or three-layered, with the threads of the layers merging integrally into the weave of the transition portion.

27. The airbag fabric according to claim 18, wherein an edge portion is adjacent to the outside of the load portion, wherein the edge portion along with the transition portion frame-like surrounds the load portion, and wherein the edge portion and the transition portion include the same weave, and, if the load portion is multi-layered, specifically two-layered or three-layered, the threads of the layers merge integrally into the weave of the transition portion and merge integrally into the single-layer weave of the edge portion.

28. The airbag fabric according to claim 18, wherein the load portion is multi-layered, specifically two-layered or three-layered, wherein the threads of the layers merge integrally into the weave of the transition portion and, if an edge portion surrounds the load portion, merge integrally into the single-layer weave of the edge portion.

29. The airbag fabric according to claim 18, wherein the load portion has a base which tapers in the load direction, specifically in the form of a trapezoid, triangle or circular segment.

30. The airbag fabric according to claim 18, wherein the load portion defines the edge of the mounting hole over a peripheral angle of at least 60?.

31. The airbag fabric for an airbag comprising a mounting area for mounting the airbag, wherein the mounting area includes a mounting hole which is disposed in a load portion, and a transition portion which is adjacent to the load portion toward an edge of the airbag, wherein the load portion and the transition portion include different weaves and the fabric in the load portion exhibits lower resistance to displacement than in the transition portion so that a fiber bead forms of the fabric fibers of the area of the load portion, which fiber bead is adjacent to the mounting hole in a load direction, if bearing stress acts upon the mounting hole in the load direction.

32. The airbag fabric according to claim 31, wherein the weave of the load portion has a first knot density and the transition portion includes a weave having a second knot density, the first knot density being lower than the second knot density.

33. The airbag fabric according to claim 32, wherein the first knot density amounts to not more than 50%, specifically to not more than 34%, of the second knot density.

34. The airbag fabric according to claim 31, wherein the fabric of the load portion has a tear propagation resistance which amounts to at least 150%, specifically at least 200%, of the tear propagation resistance of the transition portion.

35. The airbag fabric according to claim 31, wherein the warp threads of the weave of the load portion extend perpendicularly or in parallel to the load direction.

36. The airbag fabric according to claim 31, wherein the weave of the load portion is a Panama weave.

37. The airbag fabric according to claim 31, wherein the transition portion merges into an airbag chamber portion which forms a wall of an inflatable chamber.

38. The airbag fabric according to claim 31, wherein the airbag fabric is a one-piece-woven fabric in which the threads of opposite walls of an inflatable chamber at the edge merge into a joint weave.

39. The airbag fabric according to claim 31, wherein the load portion is multi-layered, specifically two-layered or three-layered, with the threads of the layers merging integrally into the weave of the transition portion.

40. The airbag fabric according to claim 31, wherein a cushioning portion is adjacent to the load portion.

41. The airbag fabric according to claim 40, wherein the cushioning portion is adjacent to the load portion at least in the load direction.

42. The airbag fabric according to claim 40, wherein a tolerance portion or the transition portion is adjacent to the cushioning portion, or in that the cushioning portion forms at least partially the transition portion and is adjacent to the walls of the airbag.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Further advantages and features will be evident from the following description and from the attached drawings, wherein:

[0031] FIG. 1 shows a schematic section view of a part of an airbag having an airbag fabric according to the invention,

[0032] FIG. 2 shows a detail view of a mounting area of the airbag fabric of FIG. 1,

[0033] FIGS. 3 to 5 show in respective detail views further embodiments of a mounting area of the airbag fabric of FIG. 1,

[0034] FIG. 6 shows a schematic section view of a (6/6) Panama weave,

[0035] FIG. 7 shows a detail view of a mounting area of the airbag fabric of FIG. 1 with cutting lines lying within a tolerance area,

[0036] FIG. 8 shows a detail view of another embodiment of a mounting area of the airbag fabric,

[0037] FIG. 9 shows an airbag comprising further embodiments of a mounting area of the airbag fabric, and

[0038] FIGS. 10 and 11 show respective detail views of the mounting areas of the airbag fabric of FIG. 9.

DRAWINGS

[0039] FIG. 1 illustrates an airbag 10 that is formed of an airbag fabric 20.

[0040] The airbag 10 comprises an inflatable chamber 12 that is delimited by walls 14, 16 facing each other as well as an edge 18 having a mounting area 22.

[0041] As a matter of course, the airbag 10 may have any number of mounting areas 22.

[0042] In the shown embodiment, the airbag 10 is a one-piece-woven (OPW) airbag. That is, the airbag fabric 20 is a piece of OPW fabric manufactured by a weaving process, also referred to as OPW process.

[0043] The two walls 14, 16 form two layers woven in parallel whose threads are grouped, i.e., run, into a joint weave in the edge 18. Thus, the edge 18 comprises a double thread count, while each of the walls 14, 16 has a single thread count.

[0044] The tongue-shaped mounting area 22 is provided for mounting the airbag 10 using fasteners (not shown), the airbag 10 being restrained during inflation into a load direction B.

[0045] As shown in FIG. 2, the mounting area 22 has a mounting hole 24 and a load portion 26 which extends away from the mounting hole 24 in the load direction B, and a transition portion 28 which extends against the load direction B from the mounting hole 24 and the load portion 26 to the inflatable chamber 12. The load portion 26 and the transition portion 28 together surround and define the mounting hole 24.

[0046] In this case, the transition portion 28 merges integrally into the edge 18 and then into the walls 14, 16.

[0047] Furthermore, the mounting area 22 includes an edge portion 30 which, jointly with the transition portion 28, surrounds the load portion 26 frame-like in the form of a closed peripheral frame.

[0048] The transition portion 28 and the edge portion 30 have the same weave.

[0049] In an alternative embodiment, the weave of the edge portion 30 may be different from the weave of the transition portion 28.

[0050] The weave of the transition portion 28 and of the edge portion 30, respectively, is a weave having high resistance to displacement, such as a plain weave in which each of a warp thread and a weft thread cross in a knot and which therefore is referred to as (1/1) weave.

[0051] The load portion 26 has a weave which exhibits lower resistance to displacement as compared to the weave of the transition portion 28.

[0052] In the present embodiment, the load portion 26 is formed by two superimposed fabric layers having a (2/2) Panama weave, i.e., a weave in which each of two warp threads and two weft threads cross in a knot and, thus, form a checkerboard pattern each field of which has a width of two warp threads and, resp., two weft threads. Each of said fields forms a knot.

[0053] The threads of the superimposed fabric layers of the load portion 26 merge integrally into the single-layer woven transition portion 28 and the single-layer woven edge portion 30 and each has half the thread count of the transition portion 28 and, resp., the edge portion 30 in the corresponding area. As a result, the mounting area 22 is configured as a piece of OPW fabric and, thus, has a particularly simple design.

[0054] Due to this design with two layers and a (2/2) Panama weave, the knot density of the weave of each fabric layer of the load portion 26 in this case amounts to ? of the knot density of the plain weave of the transition portion 28 and, resp., of the edge portion 30 which have a single-layer design.

[0055] Basically, the load portion 26 may have any design as long as it exhibits lower resistance to displacement than the transition portion 28.

[0056] For example, the load portion 26 may include any number of fabric layers, specifically one single fabric layer or three or more fabric layers.

[0057] In addition, or as an alternative, the load portion 26 and, resp., each fabric layer of the load portion 26 may include any weave, specifically a (2/2) Panama weave or a (3/3) Panama weave.

[0058] In one embodiment, the load portion 26 includes one single fabric layer formed by a (6/6) Panama weave (see FIG. 6), i.e., a weave in which six warp threads 32 cross six weft threads 34 in a knot K. In the shown embodiment, each of the six warp threads 32 and six weft threads 34 extend in a respective double layer having three warp threads 32 and three weft threads 34 for each layer L. Consequently, said (6/6) Panama weave forms a checkerboard pattern each field of which has a width of three warp threads 32 and three weft threads 34, respectively. Each of said fields forms a knot K.

[0059] In embodiments comprising a load portion 26 with a single fabric layer, the threads of the load portion 26 preferably merge, as in the case of a load portion 26 with plural superimposed fabric layers, integrally into the single-layer woven transition portion 28 and the single-layer woven edge portion 30. Thus, each of the load portion 26, the transition portion 28 and the edge portion 30 is single-layered and has the same thread count. The load portion 26 differs from the transition portion 28 and the edge portion 30 by the type of its weave which exhibits lower resistance to displacement and specifically lower knot density than the weave of the transition portion 28 and the edge portion 30. In this way, the mounting area 22 may be configured as a piece of OPW fabric and may have a particularly simple design.

[0060] Preferably, the knot density of the weave of the load portion 26 and of each fabric layer of the load portion 26, respectively, amounts to not more than half, specifically to not more than ?, of the knot density of the weave of the transition portion 28.

[0061] Furthermore, it is of advantage when the load portion 26 exhibits tear propagation resistance which is higher by at least half than the tear propagation resistance of the transition portion 28. Preferably, the tear propagation resistance of the load portion is at least twice as high as the tear propagation resistance of the transition portion 28.

[0062] Basically, the mounting area 22 may take any shape and/or any length in the load direction B.

[0063] Specifically, in an alternative embodiment, the mounting area 22 can form a tensioning strap 44 or tether which influences a deployment behavior of the airbag 10 during inflation of the airbag 10, for example, and/or in the inflated state of the airbag 10 retains the latter at a desired position. In this case, the transition portion 28 forms a strap-shaped portion extending away from the inflatable chamber 12 particularly in the load direction B. In this way, the mounting area 22 provides the functionality of a tensioning strap 44 or a tether, respectively, so that, e.g., a separate tensioning strap 44 or tether and/or a separate attachment fitting on the tensioning strap 44 or tether is/are not required.

[0064] In the embodiment shown in FIG. 2, the warp threads 32 of the load portion 26 extend in parallel to the load direction B, while the weft threads 34 of the load portion 26 extend perpendicularly to the load direction B.

[0065] In an alternative embodiment, the weft threads 34 of the load portion 26 extend in parallel to the load direction B, while the warp threads 32 of the load portion 26 extend perpendicularly to the load direction B. This is an option which is not limited to the illustrated embodiments.

[0066] Basically, the warp threads 32 and the weft threads 34, respectively, may extend at any angle with the load direction B.

[0067] However, it is advantageous when the warp threads 32 or the weft threads 34 extend at an angle with the load direction B that ranges from 60? to 120?, specifically from 80? to 100?, so as to promote the bead formation under load which will be explained below.

[0068] The mounting hole 24 has a circular cross-section.

[0069] In an alternative embodiment, the mounting hole 24 may have any cross-section.

[0070] Further, the mounting hole 24 is arranged so that 50% of its periphery are adjacent to each of the load portion 26 and the transition portion 28. Thus, the load portion 26 defines the edge 36 of the mounting hole 24 over a peripheral angle ? of 180?.

[0071] As a matter of course, the load portion 26 can be adjacent to the mounting hole 24 over any area or peripheral angle ?.

[0072] In an alternative embodiment (see FIG. 3), the load portion 26 may be adjacent to the mounting hole 24 over a peripheral angle ? of less than 1? only.

[0073] Preferably, the load portion 26 is adjacent to the mounting hole 24 over a peripheral angle ? ranging from 60? to 180?, however.

[0074] In the embodiment illustrated in FIG. 2, the load portion 26 has a rectangular base whose sides extend in parallel and perpendicularly, resp., to the load direction B.

[0075] The load portion 26 can basically take any shape and/or any orientation relative to the load direction B.

[0076] Specifically, the load portion 26 may take a shape which tapers in the load direction B, as shown in FIGS. 3 to 5 which illustrate further embodiments of the airbag fabric 20 having alternatively designed mounting areas 22.

[0077] In the embodiment shown in FIG. 3, the load portion 26 has a base in the form of an isosceles triangle.

[0078] In the embodiment shown in FIG. 4, the load portion 26 has a trapezoidal base.

[0079] In the embodiment shown in FIG. 5, the load portion 26 has a base formed by a semicircle.

[0080] In all embodiments, the warp and weft threads 32, 34 are displaced in the load portion 26, if the fastener extending through the mounting hole 24 causes bearing stress to act in the load direction B upon the edge 36 of the mounting hole 24 adjacent to the load portion 26 by.

[0081] Unlike the fabric of the transition portion 28 which, due to the higher resistance to displacement, would tear by such bearing stress, the warp and weft threads 32, 34 are pushed together in the load portion 26 by the fastener to form a bead that is composed of the fabric fibers of the warp and weft threads 32, 34.

[0082] Said fiber bead forms a resistant barrier which can only be penetrated by a specifically high load.

[0083] Measurements made with the embodiment shown in FIG. 2 have resulted in the fact that the mounting area 22 withstands a two times higher load than the mounting area of an airbag fabric that is formed without a load portion 26.

[0084] FIG. 7 illustrates by the laser cutting lines 42 shown as dot-dash line in which area admissible tolerances in the cutting can be located in very large airbags 10, i.e., which are very long in the x direction. Accordingly, as shown in FIG. 7, in particular in those very large airbags 10 there may arise the problem that, due to the admissible tolerances, the mounting hole 24 of the mounting area 22 is not or not sufficiently adjacent to the load portion 26 of a mounting area 22 according to FIGS. 1 to 6.

[0085] By the embodiment of the mounting area 22 shown in FIG. 8, an alternative embodiment of the airbag fabric 20 according to the invention is illustrated in which the mounting hole 24 is completely enclosed by the load portion 26 and the load portion 26 is directly adjacent to the transition area 28 which merges integrally into the edge 18 and then into the walls 14, 16. This alternative embodiment helps achieve that the mounting hole 24 of the mounting area 22 is arranged, even with consideration of the admissible tolerances when cutting the airbag 10, inside the load portion 26 and a fiber bead is formed under load.

[0086] The load area 26 in such embodiment is preferably single-layered or two-layered and has a weave which includes as few knots K as possible, but sufficient knots K to prevent combing out as a reason of breakage. In this case, the selection of the weave and, thus, the number of the knots K in the load portion 26 is influenced by the selected coating of the airbag fabric 20, for example.

[0087] The type of coating can significantly influence the internal friction in the load portion and, consequently, the selection of the knot density. It has turned out in tests with the mounting area 22 of FIG. 8 that, in airbag fabrics 20 including a silicone coating, load areas 26 which have a (3/3) Panama weave or an even coarser weave for each layer exhibit excellent breaking strength.

[0088] FIG. 9 illustrates an airbag 10 that includes plural mounting areas 22, 22 according to further embodiments. The mounting areas 22 in FIG. 9 form the tensioning straps 44 of the airbag 10.

[0089] As an alternative, the mounting areas 22, 22 of the airbag 10 can also be connected to a tensioning strap 44 in the form of a separate component. The structure of the mounting area for connection of a tensioning strap 44 can correspond, even in such embodiment, to the mounting area 22, 22 of the airbag fabric according to the invention.

[0090] FIGS. 10 and 11 illustrate the mounting areas 22 and 22, resp., in a detail view.

[0091] In the embodiments shown in FIGS. 10 and 11, the mounting hole 24 is also completely surrounded by the load portion 26. In addition, the mounting portion 22 and the mounting portion 22 include a cushioning portion 38.

[0092] The cushioning portion 38 has a third knot density that is equal to the second knot density of the transition portion 28 or is preferably higher than the second knot density of the transition portion 28. In typical embodiments, the cushioning portion 38 has a single-layer design and includes a (1/1) or (2/2) Panama weave, for example. As a matter of course, the cushioning portion 38 may also include other weaves such as a (1/2) or (2/1) weave.

[0093] Preferably, the first knot density of the load portion 26 should amount to only 2% to 34% of the third knot density of the cushioning portion 38, to not more than 50% of the third knot density of the cushioning portion 38.

[0094] In particular, if the cushioning portion 38 is disposed in a direction of the load direction (B) adjacent to the load portion 26, the cushioning portion 38 can easily prevent combing out under load.

[0095] In the embodiment shown in FIG. 10, the load portion 26 is two-layered, wherein both layers have a (3/3) Panama weave. The cushioning portion 38, on the other hand, is formed by a single-layer (1/1) Panama weave. As a result, the first knot density of the load portion 26 amounts to only about 5% of the third knot density of the cushioning portion 38.

[0096] FIG. 11 illustrates a mounting area 22 which forms a partial area of a tensioning strap 44 of the airbag fabric 20 of the airbag 10.

[0097] In the shown embodiment, cushioning portions 38 are adjacent to three sides of the mounting area 22. As a matter of course, such mounting area 22 can additionally include a cushioning portion 38 also on the right side in FIG. 11 so that the load portion 26 is surrounded frame-like by the cushioning portion 38. In this way, safe formation of a fiber bead can be assisted, for example, even for a load direction B which is not oriented in parallel or perpendicularly to the warp threads 32 and the weft threads 34, respectively.

[0098] The airbag fabric 20 moreover comprises, in the embodiment illustrated in FIGS. 9 to 11, a tolerance portion 40. Said tolerance portion 40 is formed by an inexpensive and simple weave and is introduced during manufacture to the airbag fabric in the area of the (laser) cutting lines 42 forming the edge of the airbag 10.

[0099] The size of the tolerance portion 40 is selected so that, even with consideration of the admissible tolerances when cutting the airbag 10, it can be guaranteed that the cushioning portion 38 will not be severed.

[0100] As a consequence, the embodiments of the mounting areas 22 shown in FIGS. 8 to 11 can prevent, specifically for very large airbags 10, that the mounting hole 24 of the mounting area 22 is not or not sufficiently adjacent to or is not surrounded by the load portion 26.

[0101] In this way, an airbag fabric 20 having a mounting area 22, 22 is provided which can absorb high loads and can be manufactured with little effort.

[0102] Furthermore, separate reinforcing elements can be dispensed with.

[0103] The invention is not limited to the illustrated embodiments. Specifically, individual features of one embodiment can be freely combined with features of other embodiments, in particular independently of the other features of the corresponding embodiments.