DE202014009963U1 - Knit with unidirectional fibers - Google Patents

Abstract

Knit fabric for forming composites comprising: stitch threads (1, 2, 3, 4, 5) intermeshed in stitches (6) and a plurality of unidirectional threads (10, 12, 14, 16, 18, 20), wherein the stitches (6) in the warp direction extending courses (A, B, C, D, E) form and between each two adjacent courses (A, B, C, D, E) a mesh channel (M1, M2, M3) is formed , and in each case at least two of the unidirectional threads (10, 12, 14, 16, 18, 20) are bound in a mesh channel (M1, M2, M3) such that twisting or crossing of the at least two unidirectional threads (10, 12 , 14, 16, 18, 20) is prevented.

Description

The present invention relates to a knit with unidirectional threads, which has good drapability and can absorb high forces at least in the longitudinal direction of the unidirectional threads.

In modern vehicles there is a need for high strength, at least in the direction of the force to be absorbed, and for low weight. The components used must therefore be optimized in this regard. Particularly suitable for such components are composite materials. Such composites are, for example, fiber composites. The high-strength fibers are inserted as, for example, as a prefabricated fiber structure (semifinished product) in a plastic matrix. To increase the strength in several directions several mutually obliquely arranged layers of fiber fabric can be inserted.

For the production of weight and size optimized components made of fiber composites, it is increasingly important to use semi-finished products in which the amount of fiber material used is minimized and at the same time can ensure the desired strength in the required direction.

Since components usually only have to endure predetermined high forces in certain directions, preference is given to using a so-called unidirectional fiber composite or a fiber composite with unidirectional properties in which, for example, high-strength fibers running only in a predetermined direction are present. This achieves weight and material thickness reduction while maintaining high strength.

From the DE 44 23 739 C2 For example, laminate composites of a fiber-reinforced thermoplastic composite material are known, which have a reinforcing layer formed as a flat knit fabric, wherein the weft threads of the flat knitted fabric can be formed as a reinforcing yarn, whereby high forces can be absorbed in the direction of the weft threads.

From the DE 10 2005 033 107 B3 is a multiaxial textile is known in which fibers, rovings or fiber bundles are arranged unidirectionally and are taken in each case by binding threads in stitches, all binding threads always enclose only one thread, a roving or a fiber bundle and then at least two semi-finished textile products at different angles to each other be connected to each other, with no backing is required for the stitch formation of the individual semi-finished textile products.

From the WO 02/0630983 A1 is known a knit fabric, in which as a strength carrier, for example, glass fibers, aramid fibers or carbon filaments are introduced into the stitch threads with.

From the DE 1 585 079 a special knitted fabric is known, in which warp threads, which are referred to as longitudinal threads, run through the knitted fabric without being bent, as a result of which reinforcing of the knitted fabric in the longitudinal direction of the introduced warp threads is likewise achieved.

Based on the above-mentioned prior art, it is an object of the present invention to provide a knit, which in particular has good Drappiereigenschaften for creating three-dimensional fiber composites that can absorb high forces in at least one direction.

This object is achieved with a knitted fabric according to independent claim 1. Advantageous embodiments are given in the dependent claims.

In the knit, the unidirectional threads are incorporated into the knit during the knitting process, in which the stitch threads are intermeshed, such that the unidirectional threads are held in the knit without additional weft threads or additional stitching or stitching.

In particular, at least two unidirectional threads per mesh channel are provided and incorporated into the knitted fabric such that twisting or crossing of the unidirectional threads, in particular of the unidirectional threads running in the same mesh channel, is prevented. This is preferably achieved in that adjacent unidirectional threads running in the same mesh channel extend at least once, preferably several times, more preferably in a certain repeat, and even more preferably always on different sides of the mesh thread sections spanning the mesh channel.

As a result, a particularly intrinsically stable knit is achieved, in which the unidirectional threads are particularly ordered and straight, at the same time a very good drapability is achieved. Furthermore, it can be prevented that due to a rotation or a crossing of the unidirectional threads an elasticity of the fabric in the longitudinal direction thereof is formed. The good drapability arises in particular in that the basic knit or basic knit formed from the stitch threads is elastic and has elasticity the introduction of the unidirectional threads is preferably not affected.

The free spaces between the unidirectional fibers, which may form during draping (stretching in the transverse direction), are evenly distributed due to the integration of the unidirectional fibers into the knitted fabric.

Furthermore, the knit can be produced integrally with unidirectional threads particularly quickly and easily, since no additional Aufnähprozess is required.

The terms thread, stitch or unidirectional thread as used herein are intended to include, for example, monofilaments, monofilaments, rovings, bundles of fibers, yarns, threads and / or wires.

Further advantages and expediencies will become apparent from the following description of the embodiments with reference to the drawings.

1 shows a knitted fabric according to a first embodiment.

1 shows the top of a cutout of a knit 100 in Trikotbindung according to a first embodiment. In the in 1 The detail shown are the mesh threads 1 . 2 . 3 . 4 . 5 meshed together to form this bond (basic weave or foundation). Characteristic of the tricot binding is that each stitch-forming thread (stitch thread) in the warp direction (hereinafter also referred to as longitudinal direction), the in 1 the Y-direction corresponds, alternately with the respective in the weft direction (hereinafter also referred to as transverse direction), the in 1 the X-direction corresponds to adjacent mesh threads is meshed.

That is how it looks like 1 it can be seen, the mesh thread 2 is in the warp direction alternately with the stitch thread 1 and the stitch thread 3 meshes, the mesh thread 3 is in the warp direction alternately with the stitch thread 2 and the stitch thread 4 meshed and the mesh thread 4 is in the warp direction alternately with the stitch thread 3 and the stitch thread 5 meshed.

As a result, in the longitudinal direction Y substantially parallel courses A, B, C, D are formed, which are arranged side by side in the transverse direction X of the knitted fabric. Between the courses so-called mesh channels M1, M2, M3 are formed.

Every stitch 6 is formed by forming a loop forming portion 7 (Also called "underlay") of a first stitch through a loop forming section 8th an adjacent stitch thread runs. Thus, a loop made of a stitch thread is inserted into a loop of another stitch thread or carried out. The portions of the mesh which do not form a loop and connect the courses A, B, C, D with each other become portions which span as spans 9 (also called "reflection") as designated.

Each mesh channel M1, M2, M3 is covered by span sections 9 made from one of the mesh threads 2 . 3 . 4 due to the alternating meshing with the respective adjacent stitched thread 1 to 5 be trained, spanned.

In each case, two unidirectional threads run through these mesh channels M1, M2, M3 in the present embodiment 10 . 12 . 14 . 16 . 18 . 20 ,

As 1 can be seen, runs a first unidirectional thread 10 essentially in a straight line in the warp direction or longitudinal direction in the mesh channel M1 through the knitted fabric. In particular, the first unidirectional thread runs 10 in 1 in the warp direction, first over (ie, on top of) two sections spanning the mesh M1 9 of the mesh 2 , then below (ie, on the underside of) two sections spanning the mesh channel M1 9 of the mesh 2 and then again over two the mesh channel M1 spans sections 9 of the mesh 2 etc.

That is, the first unidirectional thread 10 alternately passes over and under the sections spanning the first mesh channel M1 9 of the mesh 2 ,

In the same first mesh M1 is another, adjacent, second unidirectional thread 12 essentially parallel to the first unidirectional thread 10 arranged on the respective opposite sides of the mesh channel M1 spans sections 9 of the mesh 2 runs. In other words, the second unidirectional thread 12 runs in the warp direction in 1 first under (on the bottom of) two sections spanning the first mesh M1 9 of the mesh 2 , then via (on top of) two sections spanning the mesh M1 9 of the mesh 2 and then again under two sections over the mesh channel M1 9 of the mesh 2 etc.

Due to the alternating course of each of the unidirectional threads 10 . 12 over a pair of the mesh channel M1 spanning sections 9 and under it become the unidirectional threads 10 . 12 each in the knit 100 fixed. Due to the opposite course of the adjacent unidirectional threads 10 . 12 in the same mesh M1 above or below the same mesh channel M1 spans sections 9 becomes a mutual twisting or crossing of the stitch threads 10 . 12 prevented.

The other unidirectional threads 14 . 16 . 18 . 20 are pairwise in the respective adjacent mesh channels M2 and M3 substantially corresponding to the first pair of unidirectional threads 10 . 12 arranged.

In this embodiment, in the second mesh channel M2 adjacent to the first mesh channel M1, the unidirectional threads are interchanged. That is, in the positive transverse direction X first unidirectional thread 14 in the mesh channel M2 runs corresponding to the second unidirectional thread in the positive transverse direction X. 12 in the mesh channel M1 first under the mesh channel M2 spanning portions 9 of the third stitch thread 3 during the second unidirectional thread in the positive transverse direction X. 16 first over the sections spanning the second mesh channel M2 9 of the third stitch thread 3 runs.

In the third mesh channel M3 are the unidirectional threads 18 . 20 according to the unidirectional threads 10 . 12 arranged in the first mesh channel M1.

In the following, further possible embodiments are described:
The unidirectional threads need not be provided in each mesh channel. Rather, individual mesh channels can remain free and the unidirectional threads are introduced with a predetermined repeat or even without regularity in any mesh channels.

In a preferred embodiment, the unidirectional threads may be fixed exclusively by the stitch threads. In this case, the knit has no additional weft threads holding the unidirectional threads, and the unidirectional threads are not additionally sewn.

The mesh formed from the mesh threads (here knitted fabric) has an elasticity or extensibility, which depends on the material used and / or the bond used and / or the density of the bond or tension, is acted upon. By introducing the substantially non-elastic and non-stretchable unidirectional threads into the knitted fabric, the stretchability thereof is prevented in the longitudinal direction of the unidirectional threads.

In the direction perpendicular to the direction of the unidirectional threads, the knit remains elastic. In order to influence this elasticity or elasticity in the direction perpendicular to the longitudinal direction of the unidirectional threads, weft threads can additionally be introduced in regions or with a specific repeat, which connect the intermeshed stitch threads and / or unidirectional threads such that a stretchability or elasticity in the Transverse direction is also limited.

The mesh threads are formed for example of mineral or synthetic or metallic yarn and / or wire. For example, polyester having a thickness of dtex 110 is used. By the use of metallic conductors a heating, shielding or antistatic function can be realized.

The unidirectional threads are formed for example of carbon, glass, basalt, synthetic fibers or hybrid yarns or metal wires. For example, carbon with a thickness of K50 is used.

In the production of the knitted fabric, the stitch-forming rail is preferably arranged in front of the rails provided for the unidirectional threads. Furthermore, the knitted fabric is preferably formed only by a single stitch-forming guide rail or identically moving laying rails.

The knit can be produced endlessly and / or in different widths. The present invention is not limited to the specific in 1 but can be applied to any binding as long as the claimed features are met. This means, in particular, that it is also conceivable to have layers in which the stitch threads span at least two mesh channels and thus at least one course of stitches. In such a binding, adjacent unidirectional threads also run in such a way that they do not run on the same side, but on different sides, within a repeating pattern (repeat) at least with respect to a mesh channel spanning section of a mesh thread.

In a mesh channel more than two unidirectional threads can be arranged, as long as each adjacent threads on different sides of at least one mesh channel spanning portion of a mesh thread.

In the above-described first embodiment, the single thread mesh spanning stitch thread portions consist of one and the same stitch thread, which alternately forms stitches in the adjacent stitch courses. The present disclosure is not limited to this, but also includes embodiments in which the single-meshed spanning stitched mesh portions are derived from different mesh threads. There are any knitting patterns or bonds included, as long as adjacent unidirectional threads run substantially parallel through the knitted fabric and can not cross over or under at least one stitch thread due to the opposite course.

It is explicitly pointed out that all features disclosed in the description and / or the claims are considered separate and independent of each other for the purpose of original disclosure as well as for the purpose of limiting the claimed invention independently of the feature combinations in the embodiments and / or the claims should. It is explicitly stated that all range indications or indications of groups of units disclose every possible intermediate value or subgroup of units for the purpose of the original disclosure as well as for the purpose of restricting the claimed invention, in particular also as the limit of a range indication.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4423739 C2 [0005]
• DE 102005033107 B3 [0006]
• WO 02/0630983 A1 [0007]
• DE 1585079 [0008]

Claims (12)

Knitted fabric for forming composite materials with: stitch threads ( 1 . 2 . 3 . 4 . 5 ) in mesh ( 6 ) are meshed together, and a plurality of unidirectional threads ( 10 . 12 . 14 . 16 . 18 . 20 ), the stitches ( 6 ) in the warp direction extending courses (A, B, C, D, E) form and between each two adjacent courses (A, B, C, D, E) a mesh channel (M1, M2, M3) is formed, and in each case at least two the unidirectional threads ( 10 . 12 . 14 . 16 . 18 . 20 ) are so bound in a mesh channel (M1, M2, M3) that a twisting or crossing of the at least two unidirectional threads ( 10 . 12 . 14 . 16 . 18 . 20 ) is prevented. The knit of claim 1, wherein the knit fabric has a first side and a second side, each mesh channel of sections (Fig. 9 ) at least one stitch thread ( 1 . 2 . 3 . 4 . 5 ) which comprises at least two unidirectional threads ( 10 . 12 . 14 . 16 . 18 . 20 ) a first unidirectional thread ( 10 . 14 . 18 ) and a second unidirectional thread ( 12 . 16 . 20 ), the first unidirectional thread ( 10 . 14 . 18 ), when the first side of the knitted fabric is considered, under at least a first spanning a mesh channel (M1, M2, M3) portion ( 9 ) of a mesh ( 1 . 2 . 3 . 4 . 5 ) and at least a second spanning the mesh channel (M1, M2, M3) section ( 9 ) of a mesh ( 1 . 2 . 3 . 4 . 5 ) and the second unidirectional thread arranged in the same mesh channel (M1, M2, M3) (FIG. 12 . 16 . 20 ), when the first side of the knitted fabric is observed, over the first spanning the mesh channel (M1, M2, M3) portion ( 9 ) of a mesh ( 1 . 2 . 3 . 4 . 5 ) and under the second section spanning the mesh channel (M1, M2, M3) ( 9 ) of a mesh ( 1 . 2 . 3 . 4 . 5 ) passes through. A knit according to claim 2, wherein the first unidirectional thread ( 10 . 14 . 18 ) with a predetermined repeat when viewing the first side of the fabric above and below the sections spanning the mesh channel (M1, M2, M3) ( 9 ) one or more stitch threads ( 1 . 2 . 3 . 4 . 5 ), and the second unidirectional thread ( 12 . 16 . 20 ) with the same predetermined repeat when viewing the first side of the fabric above and below the sections spanning the mesh channel (M1, M2, M3) ( 9 ) one or more stitch threads ( 1 . 2 . 3 . 4 . 5 ), wherein a starting point of the repeat of the first unidirectional thread ( 10 . 14 . 18 ) to a starting point of the repeat of the second unidirectional thread ( 12 . 16 . 20 ) is offset in the longitudinal direction (Y). A knit according to claim 2 or 3, wherein the first unidirectional thread ( 10 . 14 . 18 ) with respect to the second unidirectional thread ( 12 . 16 . 20 ) on the other side of each of the mesh channels (M1, M2, M3) spans sections ( 9 ) one or more stitch threads ( 1 . 2 . 3 . 4 . 5 ) runs. A knit according to any one of claims 1 to 4, wherein there is no weft insertion for holding the unidirectional threads ( 10 . 12 . 14 . 16 . 18 . 20 ) is present in the knit. Knitted fabric according to one of Claims 1 to 5, in which the unidirectional threads ( 10 . 12 . 14 . 16 . 18 . 20 ) are tied in the same way with the stitch, and / or the unidirectional threads ( 10 . 12 . 14 . 16 . 18 . 20 ) are alternately tied into the stitch Knitted fabric according to one of claims 1 to 6 with a weft insertion, which is registered with a predetermined repeat. Knitted fabric according to one of Claims 1 to 7, in which the unidirectional threads ( 10 . 12 . 14 . 16 . 18 . 20 ) are made of different materials, and / or the unidirectional threads ( 10 . 12 . 14 . 16 . 18 . 20 ) have different strengths. Knitted fabric according to one of claims 1 to 8, in which not in each stitch channel (M1, M2, M3) unidirectional threads ( 10 . 12 . 14 . 16 . 18 . 20 ) are arranged. Knitted fabric according to one of claims 1 to 9, in which individual stitch threads ( 1 . 2 . 3 . 4 . 5 ) are made of mutually different materials, and / or have mutually different thicknesses. Knitted fabric according to one of claims 1 to 10, wherein at least one stitch thread ( 1 . 2 . 3 . 4 . 5 ) and / or at least one unidirectional thread ( 10 . 12 . 14 . 16 . 18 . 20 ) is formed metallically conductive. Knitted fabric according to one of Claims 1 to 11, in which the unidirectional threads ( 10 . 12 . 14 . 16 . 18 . 20 ) are formed from carbon, glass, basalt, synthetic fibers or a hybrid yarn, and / or the mesh threads ( 1 . 2 . 3 . 4 . 5 ) are formed of a mineral, synthetic or metallic yarn.

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