At least three layers of air bags woven together

Abstract

The present invention relates to an integrally woven OPW airbag having warp and weft yarns interwoven with at least three woven fabric layers, a lower fabric layer (UG), an upper fabric layer (OG) and an intermediate fabric layer (MG) arranged therebetween, characterized in that the warp and weft yarns of the intermediate fabric layer (MG) are floated in a selected pass-through region (DSB).

Description

[Technical Field]

[0001] The present invention relates to an OPW air bag (luftsack) having at least three woven fabric layers: a lower fabric layer, an upper fabric layer and an intermediate fabric layer disposed therebetween. [Background technology]

[0002] So-called far-side airbags, also known as front center airbags, are positioned, for example, on the driver's side of a car facing the front passenger seat. These airbags will be used in the future to meet the Euro NCAP test requirements, which are expected to come into force in 2020. The test procedures for this can be found, for example, on the Internet in the document "euro-ncap-far-side-test-and-assessment-protocol-v10.pdf." See also the "European New Car Assessment Programme" at www.euroncap.com.

[0003] Such airbags have traditionally been produced using the so-called cut, seal, and sew process, which requires extensive laborious production. In this process, multiple fabric pieces are cut from one or more fabric strips, coated with a sealant, and then sewn together to form an airbag, which is costly and time-consuming. To ensure the maximum possible protection for vehicle occupants, such airbags must have a well-defined shape and extremely high rigidity in the inflated state. Known airbags for this application represent a laborious solution and are currently produced with considerable sewing effort. For example, two or more identical or partially identical or different fabric parts are cut from a single silicone-coated plain woven fabric, the edges are sprayed with a sealant, for example in the form of a peripheral bead, and the two or more fabric parts are then superimposed and bonded together to form a bonded composite. Furthermore, the fabric layers are often seamed to ensure sufficient adhesive strength. Further components, such as safety belts and buckles, must be sewn on (with or without sealant) in a further process step to give the shape. This method is very time-consuming and costly, requiring many manual process steps. The structural space available in the vehicle seat for the complete module is very limited. In sewn far side airbags, the seams and multiple fabric layers are very bulky, increasing the structural space requirement.

[0004] European Patent Application Publication No. 3,127,758 discloses a far side airbag device having a multi-stitched two-layer airbag, the interior of which is sewn with various precisely sized and positioned fabric pieces that lie parallel to the outer layer in order to control the spatial configuration that is achieved when the two-layer airbag is inflated. Additionally, a precise joining seam is provided to join the two outer fabric layers. From the description therein, it can be seen that manufacturing a far side airbag is very laborious and time-consuming.

[0005] German Patent Application Publication No. 10 2019 002 441 discloses an OPW airbag having at least three woven fabric layers: a lower fabric layer, an upper fabric layer, and an intermediate fabric layer disposed therebetween. In this case, the warp and weft threads of the intermediate fabric layer exit the intermediate fabric layer in a first partial region of the OPW airbag, are completely suspended between the upper and lower fabric layers, and are integrated into the lower or upper fabric layer in a second partial region of the OPW airbag. However, the proposed design occupies a large amount of space, which makes it impossible to install in very tight spaces, such as when arranging a knee airbag in a car. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to propose an air bag in which the drawbacks known from the prior art are avoided or at least significantly reduced. [Means for solving the problem]

[0007] The above problem is solved by an integrally woven OPW airbag according to claim 1, namely: The problem is solved by an OPW airbag having warp and weft threads interwoven with at least three woven fabric layers: a lower fabric layer, an upper fabric layer, and an intermediate fabric layer disposed therebetween, characterized in that the warp and weft threads of the intermediate fabric layer float in a selected pass-through area. The OPW airbag according to the present invention is advantageously a one-piece woven airbag, which is fully woven when it leaves the loom and advantageously already possesses all of its functional features. The design according to the present invention allows the airbag to be made very small and compact in space, and thus can be used in particular for designing knee airbag arrangements. The warp and weft threads floating in the pass-through area are not bound to each other by the weave. Therefore, the intermediate fabric layer in this area is air permeable. For example, air supplied between the upper and middle fabric layers can flow through the passage area of ​​the middle fabric layer and reach the area between the middle and lower fabric layers. Naturally, the same can occur in the other direction. As air flows through the passage area, the warp and weft threads of the middle fabric layer deviate laterally from their respective thread paths, allowing the incoming air to flow through the middle fabric layer. The airbag according to the present invention does not require a separately arranged so-called inlet area known from the prior art and can therefore be significantly smaller than previously known airbags. To meet the various defined sealing requirements, it is only necessary to provide individual sealants. This significantly reduces costs and shortens manufacturing time compared to airbags known from the prior art. Both chambers can be filled simultaneously by a generator or inflator during the inflation process, resulting in an already stable airbag. The aim is to meet Euro-NCAP requirements using this basic design.

[0008] In an advantageous embodiment of the invention, the OPW airbag is characterized in that the selected passage area is surrounded by a peripheral area in which there is a tighter weave than the basic weave of the intermediate fabric layer.

[0009] If the design (keyword "incorporation") of the lower and / or upper fabric layer does not allow the intermediate fabric layer to be formed as a plain weave in the pass-through area, a basic weave of the intermediate fabric layer, e.g. a weave narrower than the plain weave, can be installed as reinforcement partially around the floating warp and weft thread area.

[0010] In another advantageous embodiment of the invention, the OPW bladder is characterized in that the upper and intermediate textile layers are connected to one another in selected regions via X-tethers. This configuration according to the invention allows targeted control of the individually desired shape of the space between the upper and intermediate textile layers. Again, in the selected regions where the two textile layers are connected to one another via X-tethers, the invention advantageously allows the local stretching and extent of the bladder upon inflation to be intentionally limited.

[0011] In a similar advantageous embodiment of the invention, the OPW airbag is characterized in that the lower and middle textile layers are connected to each other in selected areas via X-tethers, and what has been said about the previous embodiment also applies here.

[0012] A further advantageous embodiment of the OPW air bag according to the invention is characterized in that the upper and intermediate fabric layers form an upper air chamber between them, and the lower and intermediate fabric layers form a lower air chamber between them, the upper air chamber having a generator orifice for accommodating a generator. The advantage of this arrangement is, in particular, that all air chambers of the air bag can be filled via a single generator orifice.

[0013] In yet another advantageous embodiment of the invention, the OPW bladder is characterized in that it has a reinforcing chamber in the upper and / or lower chamber, which, according to the invention, allows for controlled bending of one part of the bladder relative to another part of the bladder upon inflation.

[0014] In a further advantageous embodiment of the invention, the OPW airbag is characterized in that X-tether rows are arranged in the upper and / or lower air chamber.

[0015] Various arrangements of X-tether rows and reinforcement chambers allow individual sections to precisely curve relative to other sections when the bladder is inflated.

[0016] In a final advantageous embodiment of the invention, the OPW air bag is characterized in that it comprises a polymer layer on its outer surface, such a coating with a sealant advantageously increasing the air impermeability of the textile layer and therefore the shape stability of the air bag under inflation pressure.

[0017] In particular, the subject matter of the present invention can be used in the field of knee airbags. For a better understanding of the invention, the invention will now be briefly described on the basis of exemplary embodiments with the aid of the drawings. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a highly schematic perspective view of an OPW bladder in an uninflated state, showing its three layers separated from one another; [Figure 2] FIG. 2 is a highly schematic side view of the OPW airbag of FIG. 1. [Figure 3] 1 is a highly schematic plan view of an exemplary embodiment of an OPW airbag according to the present invention with an inflator inserted therein; FIG. [Figure 4] 4 is a highly schematic view of the OPW airbag of FIG. 3 as seen from the left. [Figure 5]1 is a highly schematic view of an exemplary embodiment of an OPW airbag according to the present invention having a generator mouth, in which an inflator or generator is inserted in the generator mouth between an upper fabric layer and an intermediate fabric layer. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] 1 shows three fabric layers, namely, an upper fabric layer OG, a middle fabric layer MG, and a lower fabric layer UG, arranged at a large distance from one another. The upper fabric layer OG and the lower fabric layer UG comprise warp threads KF and weft threads SF interwoven with one another in a consistent manner, for example, in a plain weave L1 / 1. The middle fabric layer MG also has warp threads KF and weft threads SF extending in a passing region DSB, which is shown as a rectangular grid-like surface approximately in the center of the middle fabric layer, but they are free-floating. That is, as known to those skilled in the art, in this region the warp and weft threads KF, SF are not connected to one another by a weave but are displaceable parallel to and transverse to their longitudinal direction in the fabric layers. When an air flow LS is applied transversely to the intermediate fabric layer MG in the passing region DSB, the warp and weft yarns KF, SF are deflected laterally in this region, allowing them to pass through the intermediate fabric layer in this region in the direction L shown.

[0020] On the left side of Figure 1, the running directions of the warp and weft threads KF, SF are indicated by two arrows: K is the longitudinal direction and S is the transverse direction. Arrow II indicates the direction of view towards the fabric layers as illustrated in Figure 2. In Figure 2, for clarity, the fabric layers OG, MG, UG are shown somewhat separated. In reality, the fabric layers in the resting state lie flat and close to one another. In the cross-sectional view, the passage area DSB is visible as a dashed line, as well as an arrow L and another arrow to indicate the movement of the aforementioned air flow LS.

[0021] While the aforementioned Figures 1 and 2 are merely schematic diagrams, Figure 3 illustrates an exemplary integrally woven OPW air bag LUS according to the present invention. Viewed from above, the exemplary square-shaped air bag LUS shows an upper fabric layer OG, beneath which are located an intermediate fabric layer MG and a lower fabric layer UG, with only the transit area DSB, which is not visible in this view, as viewed in the direction of the line of sight. The three aforementioned fabric layers OG, MG, and UG are woven together to form a single fabric layer ("single layer") in the region of their periphery, a weaving seam WN. This can be clearly seen in Figure 4, which is shown as viewed along arrow IV in Figure 3, with the upper fabric layer OG and the intermediate fabric layer MG forming a space also referred to as an upper chamber OLK, and the lower fabric layer UG and the intermediate fabric layer MG forming a space also referred to as a lower chamber UK. The three fabric layers come together, so to speak, at the weaving seam WN to form a single layer in this region. The generator G is arranged at the generator mouth GM and protrudes into the upper chamber OLK. As soon as the generator G is activated, it blows air or gas into the upper chamber OLK in the direction of the arrow AL through an opening, for example located in its head, thereby filling it. Almost simultaneously, air flows according to the arrow L through the passage area DSB and, unhindered by the floating threads of the passage area DSB, into the lower chamber UK of the air bag LUS, filling it as well. The fabric layers of the lower chamber UK, i.e., the lower fabric layer UG and the middle fabric layer MG, are interwoven with one another via the diagrammatically indicated interwoven seam UWN, which thus seals the lower chamber UK from the outside.

[0022] The generator G, which is shown loosely positioned in the air chamber OLK in FIG. 4, is actually in close contact with the upper fabric layer OG and the middle fabric layer MG, as shown in FIG. 5. The generator G, shown in solid lines, is positioned in the air bag, shown in dashed lines. The perspective view of FIG. 5 shows the air bag LUS in an uninflated state, with the generator G inserted into the generator mouth GM. It should also be noted that the generator G would be located between the upper fabric layer OG and the middle fabric layer MG. The passage area DSB, shown in dashed lines in FIG. 5, is not actually visible in the illustration and is only suggested for clarity.

[0023] The situation shown in Figure 4 shows an idealized situation for simplicity in which an air bag according to the invention is inflated. Compared to solutions known from the prior art, the compact and small design of the air bag according to the invention can be seen, which does not have its own inlet area and is therefore very well suited for use as a knee air bag in tight space conditions, for example in the footwell area of ​​a motor vehicle.

[0024] In this case, the above-mentioned passage area DSB allows the air chambers located above or below it to be filled with gas not slowly when the generator is activated, but quickly and dynamically, thanks to the intermediate fabric layer MG having partially floating warp and weft threads KF, SF. The floating threads of the intermediate fabric layer MG form an air passage in this area, which allows dynamic air exchange between the two overlapping air chambers OLK, ULK.

[0025] The fabric layers of the air bag according to the invention can be selectively provided with so-called X-tethers, which are placed at precisely targeted locations, in order to limit local stretching during inflation. The aim is, inter alia, to propose an air bag that allows for high stiffness and an improved three-dimensional shape in the inflated state. A key solution in this regard is to propose one or more air passages, created by floating warp and weft threads, at appropriate design points, even in tight situations, which connect the upper and lower air chambers OLK, ULK with each other and allow for rapid air exchange, such as the pass-through area DSB mentioned herein.

[0026] The above-mentioned reinforcement structure, for example a plain weave, in the intermediate fabric layer around the passage area prevents damage to the passage area due to mechanical or thermal loads. In order to achieve the planned filling speed of the individual overlapping air chambers, it is important that the cross section of the DSB in the passage area maintains the designed size.

[0027] If the design (keyword "integration") of the lower and / or upper textile layers UG and / or OG does not allow the intermediate textile layer MG to be formed as a plain weave in chamber areas where air passage according to the invention by floating warp and weft threads should not occur, a basic weave of the intermediate textile layer MG, e.g. a weave narrower than the plain weave, can be installed at least partially around the floating areas as reinforcement.

[0028] The filling speed of the chambers can also be influenced by the size of the area of ​​the passage area in the intermediate fabric layer. This means, for example, that the upper air chamber, which is filled by the generator in this example, can be pressurized faster or slower by enlarging or reducing the cross-section of the passage area to the lower air chamber. This also means that an air chamber that is not filled directly by the generator but only indirectly through the passage area in the intermediate fabric layer can be filled dynamically or less dynamically in the above-mentioned dependency. This allows the lower or upper air chamber of the air bag to be filled faster or slower as appropriate. This, of course, is only noticeable in the highly dynamic range, but it contributes positively to optimizing the deployment / delivery of the air bag according to the invention from the air bag module. [Explanation of symbols]

[0029] AL blown air DSB passing area G generator GM generator mouth L arrow LS Airflow LUS air bag MG intermediate woven layer OG upper textile layer OLK upper air chamber UG lower textile layer ULK lower air chamber UWN lower woven seam WN woven seam

Claims

1. 1. An integrally woven OPW airbag having warp and weft yarns interwoven in at least three woven fabric layers, namely a lower fabric layer (UG), an upper fabric layer (OG), and an intermediate fabric layer (MG) disposed therebetween, wherein the intermediate fabric layer (MG) includes a basic weave, a passage region (DSB), and a peripheral region, wherein the warp and weft yarns of the intermediate fabric layer (MG) are suspended in the passage region (DSB), and the passage region (DSB) is surrounded by the peripheral region in which a weave denser than the basic weave of the intermediate fabric layer (MG) is present.

2. 2. The OPW airbag according to claim 1, characterized in that the upper fabric layer (OG) and the middle fabric layer (MG) are connected to each other via X-tethers in selected areas.

3. 2. The OPW airbag according to claim 1, characterized in that the lower fabric layer (UG) and the middle fabric layer (MG) are connected to each other via X-tethers in selected areas.

4. The upper fabric layer (OG) and the intermediate fabric layer (MG) form an upper air chamber (OLK) therebetween, and the lower fabric layer (UG) and the intermediate fabric layer (MG) form a lower air chamber (ULK) therebetween; 2. The OPW air bag according to claim 1, characterized in that the upper air chamber (OLK) has a generator mouth (GM) for accommodating a generator (G).

5. 5. The OPW airbag according to claim 4, characterized in that the OPW airbag has a reinforcing chamber in the upper air chamber (OLK) and / or in the lower air chamber (ULK).

6. 6. The OPW airbag according to claim 5, characterized in that an X-tether row is arranged in the upper air chamber (OLK) and / or the lower air chamber (ULK).

7. 2. The OPW air bag of claim 1, wherein the OPW air bag comprises a polymer layer on its outer surface.

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