WO2007118672A1

WO2007118672A1 - Woven fabric

Info

Publication number: WO2007118672A1
Application number: PCT/EP2007/003262
Authority: WO
Inventors: Graefe Hans-Albert
Original assignee: Itg Automotive Safety Textiles Gmbh
Priority date: 2006-04-12
Filing date: 2007-04-12
Publication date: 2007-10-25
Also published as: DE102006017274A1

Abstract

Woven fabric having warp threads and weft threads, having a thermal protection device which is attached at least on one side of the woven fabric, which woven fabric is distinguished by the fact that the thermal protection device has sacrificial threads (OSS) which are woven in and in regions float over the woven fabric (2).

Description

tissue

The present invention relates to a fabric with warp thread and weft thread, with a heat protection device attached at least on one side of the fabric.

In passenger restraint systems for motor vehicles, airbag systems are used in which airbags are used, which are also equipped with hot gas generators, among other things, to fill the airbags with gas and thus to inflate. In this case, propellant gases are introduced into the airbag with temperatures up to 1000 ° C, which sometimes come into contact with the airbag fabric even at approximately these temperatures. This has the consequence that the fabric of the airbag is currently fully or partially constructed so that it can survive these temperatures without damage, d. H. for example, that such fabrics have such a high heat capacity that they can not burn through or that they are protected by a corresponding coating as heat protection against burn-through.

In the case of single-piece woven airbags, known as OPW bags, such heat capacity-increasing measures can only be applied from the outside. If heat protection is to be achieved in certain zones, additional manufacturing steps such as coating, sewing or patching and the like are required.

Heat protection devices which are attached to a single airbag require additional piece control in terms of their quality of execution, which means additional costs. If airbags are generally produced by using thicker yarns, for example dtex 700, to make them more heat-resistant, there is more space in the vehicle required, which also leads to an increase in costs. In addition, this is an addi tional silicone coating for the purpose of isolation partially required.

If more material mass is used according to the required heat capacity for the entire airbag construction than with conventional airbags, for which the other technical parameters would not otherwise be necessary, also significantly higher costs.

Known from the German Patent 101 15 890 so-called embroidery shooting technology proposes to increase the mechanical and thermal strength and thus to avoid airbag cracks in desired airbag positions in the fabric weft yarns of a certain strength only over certain Kettfadenlängenbereiche register, especially weft yarns with a higher enter second yarn thickness with unchanged weft density or weave weft yarns of a higher third yarn thickness. This method does not always provide the desired success in a satisfactory manner.

The invention has for its object to provide a tissue with a mounted on at least one tissue side heat protection device with which the known from the prior art disadvantages are avoided or at least greatly reduced.

The object is achieved with a fabric according to claim 1. Advantageously, such a fabric can already receive a heat protection device during the weaving process. The fabric itself may be constructed of fine denier yarns, and if the fabric is used for an airbag in which several layers are sewn together, it follows due to the inventive design of the fabric that a sewing thread remains firmly anchored in the base fabric. Penetration points are covered by the construction of the heat protection device and thus can not be stretched. As a result, such a manufactured airbag retains its required quality features throughout the course of its use.

Furthermore, the advantage of the fabric according to the invention is that an additional costly attachment of heat protection elements to the production of the fabric on the airbag is eliminated. A tissue construction required for the case of an airbag may take account of the specific requirements of the generator intended for module assembly, wherein in a manufacturing process, namely weaving, binding, threading and / or thread thickness as well as material (eg polymer) for the heat protection device can be selected. The woven sacrificial threads acting as a heat protection device form a protective barrier upon exposure to the tissue with hot fluids and protect the actual tissue from thermal attack, possibly destroying itself; hence the term sacrificial threads. The tissue according to the invention thus consists, as it were, of a base fabric, preferably a construction in canvas 1/1 weave and a sacrificial fabric consisting of sacrificial threads and attached to at least one fabric side, which represents the heat protection device.

In an advantageous development of the invention, the sacrificial threads floating over the tissue in sections may be formed as weft threads. In this simplified procedure, the selection of sacrificial threads has no influence on the selection of the warp threads. In a further development of the fabric according to the invention, the latter also has sacrificial warp threads which in some cases float both over the weft threads and over the warp threads of the base fabric. This has the particular advantage that this construction is actually a sacrificial fabric of its own, which consists of woven-in warp and weft sacrificial threads and has been selectively applied to the ground fabric.

In a further advantageous embodiment of the invention, the fabric is formed as a two-day fabric with an upper fabric and a lower fabric, wherein the heat protection devices of the upper fabric and the lower fabric are each arranged facing each other. This construction is now especially for use in one-piece woven airbags, so-called OPW airbags advantage. Herein always two-ply tissue areas are arranged with a lower tissue and an upper fabric, which pass in places in single-ply areas or even once again "branched" in multi-layered areas. The construction of a multi-ply OPW airbag as such is known to the person skilled in the art and is therefore not particularly carried out at this point. However, it is the person skilled in the art at this point also particularly the valence of the present invention, namely for the first time ever an OPW airbag in the interior area by weaving a realized by sacrificial thread heat protection device, so to speak, "coated". Of course, it is within the scope of the present invention to use special, particularly heat-resistant sacrificial threads to bring as a heat protection device the required resistance to thermal attack.

In a further advantageous embodiment of the invention, the fabric is executed with woven sacrificial threads having non-round cross-sections. With the invention Fabric as well as with the airbag according to the invention can be achieved, in particular by the latter embodiment with woven sacrificial threads with non-round cross-sections, the advantageous effect that when pressure applied to an airbag formed therefrom or airbags, the sacrificial tissue to the adjacent fabric layer sealingly applies and in this case the permeability of the tissue - in response to the pressurization - changes.

In a further advantageous embodiment of the invention, a method for controlling the internal pressure in an airbag is proposed, which is characterized by using a fabric according to one of claims 1 to 9 for the wall of the airbag, wherein the air permeability (LD) in dependence on the pressure load is controlled in the airbag.

In another advantageous embodiment of the invention, the method is characterized in that the air permeability (LD) is lowered for control with increasing Luftsack- internal pressure.

Thus, when using the fabric according to the invention, an airbag with variable or load-equivalent air permeability (LD) or corresponding permeability can be created in which the permeability is high at low internal pressure and decreases with increasing airbag internal pressure, since the tissue "closes as the pressure increases "or because the tissue pores widening under pressure are closed by pressing the sacrificial thread.

In a further advantageous embodiment of the invention, the fabric is executed with sacrificial threads, which have flat, triangular, polygonal, ribbon-shaped or oval cross-sections. This simplifies the individual adaptation of the fabric to the required dynamic permeability properties.

Further special features of the invention can be found in the dependent claims. The already mentioned use of the fabric according to the invention in airbags for motor vehicles and the advantages that were associated with them were emphasized in what has been said so far.

In the following, the invention will be briefly described with reference to some embodiments with reference to the accompanying drawings. Fig. 1 shows a schematic representation of an OPW fabric in section with embroidery in satin weave and L 1/1 -Grundbindung.

FIG. 2 shows the schematic representation of a sectional view of a flat fabric with embroidery stitch in satin weave and L 1/1 plain weave.

Fig. 3 shows a binding cartridge and a schematic representation of a sectional view of a L 1/1 flat tissue with a sacrificial tissue consisting of warp and

Shot Atlas. 4 schematically shows a side belt airbag for motor vehicles, designed as an OPW

Bag with the particular arrangement of a sacrificial layer in a selected area of the airbag.

Fig. 2 shows a detail of the sectional view of a flat fabric 2 with warp threads 21 and 22 and with weft threads Sl, S2 and OSS. The warp threads are regularly shown as small circles. The weft threads are regularly drawn as solid lines. The skilled person is familiar with this representation. It applies to the entire description presented here. In FIG. 2 it can be clearly seen that the sacrificial embossment OSS only shows the tissue side 2 of the tissue 2 in this representation of the upper tissue side. Of course, in the schematic sectional view shown here only a sequence of weft threads Sl, S2 and OSS is shown. The repeatedly repetitive firing sequence finally results in the tissue and, thus, parallel sacrificial weft threads OSS as a protective device in front of the actual tissue 2. Thus, according to FIG. 2, the so-called sacrificial layer consists of the sacrificial stipple wefts OSS, introduced as a protective atlas using the stick-shooting technology (see above). L 1/1 flat fabric means "plain weave flat fabric with 1: 1 weft sequence".

In the schematic representation according to FIG. 3, a sectional image of an L 1/1 flat fabric with a sacrificial fabric consisting of warp and weft atlas can be seen again in the lower part. The sacrificial tissue results from the weft threads OSSl to 0SS8 and the sacrificial warp threads 031, whose bonding points with the base fabric are also shown here as small circles. The base fabric 3 includes weft threads 3S1 and 3S2 and the warp threads 332, which are only partially indexed for the sake of clarity.

For reasons of illustration, the schematic sectional view according to FIG. 3 takes into account only the lower quarter of the warp and weft threads of the binding cartridge shown above. However, since the system repeats itself analogously, this representation is clear to the skilled person.

Weaving is in the embodiment of FIG. 3 in the Kettfolge 2: 1 and in the firing 1: 1.

X in the cartridge indicates a binding point of a sacrificial embossment and means a warp lift.

O denotes a setting point of a sacrificial string, which means a warp reduction in the L 1/1 shot of the background fabric.

A black filled square in the cartridge according to Fig. 3 means a warp, a white or blank square means a warp reduction. If a hot generator gas now flows in the direction of the thickly marked arrow G onto the fabric 3 illustrated schematically in FIG. 3, this works in front of the base fabric, consisting of weft threads 3S1 to 3S8 and warp threads 332, "pre-hung" atlas of sacrificial threads OSS1 to OSS8 and 031 as a heat protection device in the form of a sacrificial tissue. The base fabric is thus protected by the heat protection device formed from said sacrificial threads.

Fig. 1 shows a further embodiment of the present invention as a schematic representation of an OPW fabric in section, with embroidery stitch in satin weave and canvas 1/1 -Grundbindung. The upper fabric OG consists of weft yarns Ol and 02 and sacrificial stick shot SO, which shows the sacrificial embossment SU of the lower fabric UG, which is formed as a base fabric of the weft threads Ul and U2. The mutually facing, over the warp threads KO and KU partially floating sacrificial threads SO and SU, which represent the respective heat protection device of the upper fabric and the lower fabric, are clearly visible in Fig. 1. Between the two heat protection devices, the letters G symbolize that these are the "action points" of a very high temperature generator gas which would attack the upper and lower tissues if they were not protected by the sticky sacrificial threads SO and SU, respectively.

4 schematically shows a construction of a side curtain airbag 4 equipped with the fabric according to the invention, wherein a fabric according to the invention is used in a special area OS of the airbag 4. The configuration according to FIG. 4 relates exemplary on Seitenvorhangairbags, designed as OPW bags, with so-called Mittelmo module, in which from the direction of the arrow G generator gas is passed into the airbag.

The inventive design of a fabric introducing additional mass of material in the form of a selectively connected to the actual airbag fabric or partially incorporated in this separate fabric layer as sacrificial fabric respectively heat protection device is possible. This can also be arranged on the inside of an OPW airbag via the stick-shooting technology. Advantageously, the use of a low-cost material for the sacrificial tissue of the heat protection device instead of the material for the actual airbag considerable cost savings. Advantageously, the application of the embroidery gun technology in the binding more than trivalent, the weaving technique of a sacrificial layer in the interior of a double fabric, the production of a flat fabric with woven sacrificial layer, their bonding with the ground fabric and with each other or partially into each other, as a bond more than three-stranded (eg twill, atlas, etc.) and / or as a double fabric in each L 1/1 basic construction with bonding points in warp and weft direction more than three times using the embroidery gun technology.

Particularly emphasized in the example according to FIG. 4, according to the invention, the weaving in of the sacrificial thread in the firing change is carried out according to the design of the embroidery gun on the zones which are particularly heat-stressed according to the design (OS in more than three-bladed shot atlas), whereby the firing order is 1: 1, 1: 2 or higher, depends on titer, polymer and desired protective effect.

The sacrificial thread is generally a low cost product, either with a melting point lower than that of PA 6.6 (eg, PP), to absorb so much energy under heat stress that the residual energy does not damage the ground fabric, or with a higher melting point, to increase the heat capacity increase. A sacrificial layer on an as yet symmetrical airbag fabric is formed by a weft atlas with an odd number of offsets (for a L 1/1 basic fabric) and greater than 3 (e.g., eight-bind), (Figure 3). The binding points of the embroidery shots from additional yarn (OSSl to OS S 8) in the L 1/1 basic fabric are to be laid in the direction of impact so that an even bonding point is provided with the respectively preceding weft thread of the background fabric. For airbags which are produced or "tailored" from flat fabric, the flat fabric according to the invention is particularly advantageous, for example as an insert as a patch or as a heat protection device. In this case, the sacrificial thread is introduced as a shot atlas into a symmetrical base fabric (all-over arrangement) according to the embroidery gun technology. According to the exemplary embodiment according to FIG. 4, an L 1/1 base fabric with a sacrificial tissue also setting in L 1/1 is shown. This involves weaving two flat weaves in a double-weave technique such that the sacrificial weft thread, recorded in the technique of sticking, sets in the weft atlas with the base chain (X) and sets the warp of the sacrificial tissue with the weft of the base weave in the warp (O). With this construction, it is advantageously possible to produce particularly resistant heat protection devices.

* *

Claims

1. fabric with warp and weft, with a mounted on at least one fabric side heat protection device, characterized in that the heat protection device has woven sacrificial threads (OSS), which in parts float over the fabric (2).

2. A fabric according to claim 1, characterized in that the heat protection device has woven sacrificial weft yarn, which float in parts on the warp thread.

3. Fabric according to claim 2, characterized in that the heat protection device has woven sacrificial warp thread, which float in sections on the weft threads.

4. A fabric according to claim 2 or 3, characterized in that it is designed as a two-ply fabric with an upper fabric and a lower fabric and the heat protection devices of the two fabric layers are arranged facing each other.

5. fabric according to claim 2, characterized in that it is designed as flat fabric with sacrificial weft yarns as embroidery in satin weave as heat protection device and canvas 1/1 bond as a plain weave. (Fig. 2)

6. fabric according to claim 3, characterized in that it is designed as a flat fabric with sacrificial weft yarn as embroidery and sacrificial warp in satin weave as heat protection device and canvas 1/1 bond as a basic weave.

7. A fabric according to claim 4, characterized in that the sacrificial weft threads bind as embroidery weft threads SO and SU in the Atlas format in each case in the upper fabric and lower fabric, wherein the upper fabric and the lower fabric are carried out in canvas 1/1 construction. (Fig.l)

8. fabric according to any one of the preceding claims, characterized in that the woven sacrificial threads have non-round cross-sections.

9. fabric according to claim 8, characterized in that the woven sacrificial threads have flat, triangular, polygonal, ribbon-shaped or oval cross-sections.

10. Airbag for a motor vehicle, characterized in that it consists at least partially of a fabric according to one of the preceding claims.

11. A method for controlling the internal pressure in an airbag, characterized by using a fabric according to any one of claims 1 to 9 for the wall of the airbag, wherein the air permeability (LD) is controlled in dependence on the pressure load in the airbag.

12. The method of claim 11, characterized in that the air permeability (LD) is lowered with increasing air bag internal pressure.

* * *