EP2697097A1

EP2697097A1 - One-piece woven airbag

Info

Publication number: EP2697097A1
Application number: EP12712070.7A
Authority: EP
Inventors: Michael Becker; Andreas Enderlein
Original assignee: Global Safety Textiles GmbH
Current assignee: Global Safety Textiles GmbH
Priority date: 2011-04-15
Filing date: 2012-03-16
Publication date: 2014-02-19
Also published as: WO2012139696A1; JP2014515712A; BR112013020228A2; CA2832745A1; KR20140010441A; US20150367807A1; MX2013011803A; CN103492237A; DE102011017207A1

Abstract

The invention relates to an OPW airbag for motor vehicles, having two opposing fabric layers, which delimit at least one chamber that can be filled with gas, wherein the fabric layers are made of warp and weft threads with at least one spacer that is connected to the fabric layers and delimits the spacing of the fabric layers from one another in the inflated state. The spacer is formed by several of the warp and/or weft threads, so-called tethering threads (TF2, TF3, TF4, TF5), which, relative to the inflated state, leave the area formed by the associated fabric layer and extend in the direction of the opposing fabric layer and are connected to warp and/or weft threads of the opposing fabric layer. When warp tethering threads enter the opposing fabric layer, said warp tethering threads each initially link with n weft threads and then float over at least n + 1 weft threads in the interior of the chamber, and when weft tethering threads enter the opposing fabric layer, said weft tethering threads initially link with n warp threads and then float over at least n + 1 warp threads in the interior of the chamber.

Description

ONE-PIECE-WOVEN AIRBAG

The present invention relates to an OPW airbag.

EP 1 080 996 A2 discloses a gas bag or airbag for motor vehicles with two opposing fabric layers defining a gas-fillable chamber, the fabric layers consisting of warp and weft threads and a spacer connected to the fabric layers. are provided. The spacer, when inflated, limits the spacing of the layers of fabric from one another and is formed by some of the warp threads which, based on the inflated state, leave the flat formed by their associated fabric layer and extend toward the opposite fabric layer and are joined to weft threads of the opposing fabric layer are. The spacer described here is also called a tether in professional circles and has the task here, as an integrated component of an OPW side-curtain airbag (OPW side curtains), when inflating the airbag to take over the functions of spacing and airbag shortening. In the known airbag, the floating threads (here warp threads) in the respective opposite fabric layer at a right angle thread (here weft thread) are involved. The disadvantage here is that the different voltages arising during the inflation process cause small tears along the binding line or, in the case of a coating, these expand so that small holes are formed and thus leakages are generated in the airbag. The negative consequence is a significant reduction in the service life or leak-down time of the airbag. After a side airbag during and after a crash in a possibly following roll-over phase, ie a time while the If the vehicle is allowed to maintain its inflated state several times for about five seconds before becoming flaccid due to loss of gas, the above-mentioned leaks will be fatal to the situation described.

By way of example, EP 1 080 996 A2 refers to spacers which form an X-shape in cross-section. Such spacers are also referred to as X-tethers. When inflated, the X-Tether reduces the area by 25%. In the tether area, a parabolic curvature is created in relation to the "held" full-length bag wall or fabric layer The tensioning effect is absorbed by the floating tether threads The spacers disclosed there have, for example, warp tether threads which all coexist with each other when entering the respective fabric layer As a result, the load on this one weft thread is extreme and, as discussed above, leads to microcracks in the adjacent coating or to the partial detachment of the coating from the fabric layer.

In the course of the legal requirement of the American standard FMVSS 226 (Ejection Mitigation), which prescribes rules for the post-crash life of side airbags, the performance of the gas bag described in the prior art for the reasons mentioned above is not sufficient.

The invention has for its object to propose an OPW airbag, wherein the known from the prior art disadvantages avoided or at least greatly reduced.

The object is initially achieved with an OPW airbag according to claim 1, with two opposing fabric layers which define at least one gas-fillable chamber, wherein the fabric layers of warp and weft threads are made with at least one spacer which is connected to the fabric layers and in inflated state the distance of the fabric layers bounded from each other, wherein the spacer is formed by some of the warp and / or weft threads, so-called. Tether threads, based on the inflated state, leave the surface formed by their associated fabric layer and towards the opposite Fabric layer extend and are connected to the warp and / or weft threads of the opposite fabric layer, and characterized in that warp Tether threads each on entering the opposite fabric layer first with n Bind weft threads and form a loop, then float inside the chamber for at least n + 1 weft threads. Advantageously, during the inflation of the airbag according to the invention, the resulting stresses are reduced by an improved integration of the tether threads, or are distributed statically to a plurality of locations. This can avoid tears in the inflation process in the tissue as in a possibly applied coating or lamination. In addition, the specifications of FMVSS 226 with the construction according to the invention can also be met by asymmetrical airbags with higher longitudinal rigidity.

In a further advantageous embodiment of the invention, the warp terether threads subsequently float in the chamber exterior over at least n + 1 weft threads, before they bind at least in the further course in the opposite fabric layer in a chamber bond, in particular plain weave L1 / 1. As a result, the elasticity of the construction and the tear resistance of the airbag in the connection region of the tether in the fabric layer are advantageously increased.

In yet an advantageous embodiment of the invention takes place in succession arrangement of a plurality of spacers or Tethern a systematic change of floating Kett tether threads by floats in a first spacer floated Kett tether threads not in the next spacer and there do not function as a tether. This advantageously results in a uniform distribution of the stress of the tether threads of a spacer on a plurality of tether threads. It is thus even when sequential arrangement of Tethern by the systematic change of the floating Tether, a uniform and wrinkle-free incorporation of all threads in Tetherrichtung (longitudinal direction) achieved and thus loose longitudinal threads (warp) avoided. The shear forces at the connection of the tether threads in the opposite fabric layer can be absorbed by three transverse threads. The entire tether construction is thus more stable and elastic, which leads to an increase in functional reliability. The service life is increased here and increases the guy action.

In a further advantageous embodiment of the invention, in the region of the spacer or tether, the ratio is on the one hand between embedded, remaining in the respective fabric layer and on the other hand floats threads at -S 6: 1. This proportionality has proven to be optimal. A higher thread ratio, z. B. 7: 1 and higher would increase the voltage differences. Advantageously, every fourth thread floats over the tether length. The object is also achieved with an OPW airbag according to claim 5. The details of this solution are analogous to the preceding, under the proviso that the tethers are weft threads, which set with warp threads. For comparison: In the solution of claims 1 et seq. Tie chain tether threads with weft threads.

For a better understanding of the invention and to show how it can be carried out, it will be described briefly below with reference to embodiments with the aid of a drawing, wherein the airbag, OPW airbag, bag, curtain bag respectively designate the same namely an OPW airbag should.

Fig. 1 shows the basic construction of an X-tether of the prior art.

2 shows, in section, a very highly schematic section of an airbag according to the invention and the looping of the floating tether threads in the region of the bulge and the binding into the respectively opposite fabric layer.

FIG. 3 shows, analogously to FIG. 2, a schematic of the incorporation of the respectively following floating tether thread.

4 shows the binding variants according to FIGS. 3 and 4 in plan view.

Fig. 5 shows in section a very highly schematic section of an airbag from the prior art.

FIGS. 6a to 6d show, in a further exemplary embodiment of the invention analogously to FIGS. 2 and 3, schematically the incorporation of the respectively following floating tether thread.

FIG. 1 shows the basic construction of an X-tether with an angle of inflow of 41 ° 20 'and a shortening of d to s by 25%.

100 x cos a -75%

h1 = dx sin a (airbag thickness between the airbag walls) s = dx cos α (shortened tether length) The correlation curves of tether length and tether shortening coincide at an angle of 45 °. This theoretical derivation of the tether pitch angle would correspond to a 30% reduction. In the practice of inflation tests it has been found that the inflation angle α = 41 ° 20 ', ie the reduction is 25% to 75% of the flat lying length. cos α = 0.75088x100 = 75%

The pressurization in N / cm ² x 0.70711 (sin 45 °) gives - analogous to the calculation of the sigma value after measurement of the LD dyn. - The tensile load / cm in warp and weft direction in N / cm.

The following formula N / cm x 100

= cN / Fd

Fd / cm calculated thread tension load is uniform in the transverse direction to the tether direction (weft).

In the tether direction (chain) there are a total of three different thread tension loads: in the solid area (with full thread count / cm),

in the thinned area of the bulge

according to the ratio 3: 1 - the 1, 33 times the tensile load and for the tether threads applies due to the lower thread density and the spacer function and the length shortening according to the formula

N / cm x 100 x 2

cN / tether thread

Fd / cm

4 an 8-fold tensile load, which acts as a shear force on the receiving threads of the opposite fabric layer. The tensile stress of the tether threads has to be considered constructively (titer, modulus, thread ratio) in such a way that the 8-fold tensile load in the Hooke's area takes place at <1% elongation.

The inflation thickness of the curtain bag is composed of: the thickness of the two-ply bag body

1 and the height of the parabolic bulges in the tether area (hF2 or h2 according to FIG.

The calculation of the bag height has the following procedure on the example of FIG. 1: h1 = d × sin α

= 63.83 x 0.66044

h1 = 42.17 mm

s = d x cos α

= 63.83 x 0.75088

S = 47.93 mm

During the inflation process, the tether threads cause a shortening of d to s. The arc length d of a circular section surface at the angle ß would mean a larger radius, or a longer chord. The area F1 (circle section) is therefore equated with the area F2 (parabolic section).

2 shows in section the slots A2 of the floating tether TF2 in the region of the bulge and the binding into the respectively opposite fabric layer. A circle marks the X-tether connections XTA1 and XTA2 respectively. d indicates the tether width. From the lower fabric layer U of the warp TF2 runs around circles marked weft SU of the lower fabric layer to the point XTA1 and is then under two 2 weft threads SU afloat - here begins the Tetherzone - to then float over three wefts SU. Then, a single weft thread S1 is again incorporated, after which the tether TF2 leaves the lower fabric layer U and runs up to the upper fabric layer O. There he performs the Inclusions in the upper fabric layer to the central axis MA of the tether T point-symmetrical. If the airbag inflates during use, tension is applied to the tether TF2. In the tether area, the tether TF2 then pulls on the weft threads S1 and S2 and pulls the weft threads S1 and S2 in the point of attachment to the bag center. Since, according to the invention, the tether thread, as seen from the gas-fillable chamber, floats in each case over a further three weft threads, the tension on the tissue planes is gentle.

FIG. 3 shows a further situation analogous to FIG. 2 with the slots A3 of the floating tether TF3. Here, however, the tether thread - viewed from the central axis MA (see also FIGS. 2 and 4) of the tether T - runs on the first weft thread. In addition to the slinging in the area of the parabolic bulge, it is shown that the first two transverse threads QF (in this case weft threads) absorb the transverse distortion of the tether threads alternately in the entire area of the opposing fabric layer.

Fig. 4 shows the variants of the looping, or integration of the tether threads in the respectively opposite fabric layer according to FIGS. 2 and 3 (TF2 and TF3) and according to FIG. 6 (TF2 to TF5) in plan view. In Fig. 4 left, the warp thread numbers 1 to 15 of the lower fabric are indicated from bottom to top in a column. The "regular" warp threads included in the respective fabric layer lie in a thread ratio of 4/1 between floating tether threads This exemplary illustration shows the floating tether threads from the lower to the upper weaves in an angular direction angle opposite direction.

Fig. 5 shows in section a very highly schematic section of an airbag from the prior art. Warp threads 1 bind in the lower fabric layer 12 in L 1/1 and change at a freely determinable point 3 in the upper fabric layer 14, where they - as in the lower fabric layer 12 - are involved in L 1/1. Here, all floating warp threads bind to the same weft thread. This can cause increased stresses during the inflation process which could cause small tears along the tying line and thus result in failure of the bag in use.

FIGS. 6 a to d show, in a sectional view, the examples for the construction of the stops according to TF 2 to TF 5 in the region of the bulge of the X-tether and the insertion Bonding of the tether threads in the respective opposite fabric layer. This one-ply incorporation is usually done in plain weave. But it can also be a Rips- or Panama bond, or a combination of the three bonds mentioned are used. It should be noted that the floating warp threads are not all on the same weft thread (Fig. 6a, 6b and 6c), but are distributed over at least two weft threads. This has the advantage that the load in the application can be distributed over several weft threads. The particular advantage is that the weft thread is further only stretched so that it can be the track in the areas where it floats over three or two weft threads can be released. The addition of length reduces the instantaneous force load on the weft thread and puts less stress on the point of attachment of the tether.

In the preceding description, the invention is described in such a way that the tether threads are each warp threads and are interwoven with weft threads. In the scope of the invention according to claims 5 to 8, an OPW airbag is also included, in which the tether threads as weft threads change the fabric webs and bind there with warp threads. The respective procedure depends on how the OPW airbag is placed on the weaving machine in the fabric web. Otherwise, the details are to be understood analogously. In the tether region according to claims 5 to 8, the thread systems were compared with claims 1 to 4 exchanged.

Claims

claims

1. OPW airbag for motor vehicles, with two opposite layers of fabric which define at least one gas-fillable chamber, wherein the fabric layers of warp and weft threads consist of at least one spacer which is connected to the fabric layers and in the inflated state the distance of the fabric layers The spacer is formed by some of the warp and / or weft threads, so-called tether threads, which, based on the inflated state, leave the surface formed by their associated fabric layer and extend in the direction of the opposite fabric layer and are fastened with warp threads. and / or weft threads of the opposite fabric layer are connected, characterized in that warp tether threads each on entering the opposite fabric layer first bind with n weft threads, then float inside the chamber over at least n + 1 weft threads.

2. Airbag according to claim 1, characterized in that the warp tether threads then float in the outer chamber over at least n + 1 weft threads before they bind at least in the further course in the opposite layer of fabric in a chamber binding, in particular plain weave L1 / 1.

3. Airbag according to claim 2, characterized in that in succession arrangement of a plurality of spacers or ethers, a systematic change of the floating warp Tether threads done by floating in a first spacer floated Kett tether threads not in the next spacer.

4. Airbag according to claim 1, 2 or 3, characterized in that in the region of the spacer or tether, the ratio on the one hand between integrated, remaining in the respective fabric layer and on the other hand floats threads <6: 1.

5. OPW airbag for motor vehicles, with two opposing layers of fabric defining at least one gas-fillable chamber, wherein the fabric layers of warp and weft threads are made with at least one spacer which is connected to the fabric layers and in the inflated state, the distance of the fabric layers The spacer is formed by some of the warp and / or weft threads, so-called tether threads, which, based on the inflated state, leave the surface formed by their associated fabric layer and extend in the direction of the opposite fabric layer and are fastened with warp threads. and / or weft threads of the opposite fabric layer are connected, characterized in that each shot tether threads upon entry into the opposite fabric layer bind with n warp threads, then float inside the chamber over at least n + 1 warp threads.

6. Airbag according to claim 5, characterized in that the weft Tetherfäden then float in the outer chamber over at least n + 1 warp threads before they bind at least in the further course in the opposite layer of fabric in a chamber binding, in particular plain weave L1 / 1.

7. Airbag according to claim 6, characterized in that in succession arrangement of a plurality of spacers or Tethern a systematic change of the floating shot tether threads by floating in a first spacer weft Tether threads do not float in the next spacer.

8. Airbag according to claim 5, 6 or 7, characterized in that in the region of the spacer or tether, the ratio on the one hand between integrated, remaining in the respective fabric layer and on the other hand floats threads <6: 1.