JPS61258055A - Three-dimensional knitting machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a special three-dimensional structure obtained by manufacturing and W-weaving a fibrous material.

[Conventional technology]

Honeycomb structures are widely known as structural materials with three-dimensional thickness. Honeycomb structures have extremely high strength-to-weight ratios, and are considered one of the important industrial materials of the future, especially as composite materials. However, honeycomb structures are generally formed by bonding two flat plates and a core material.
For this reason, the manufacturing process is complicated and diverse, and the problem of peeling between the core portion and the flat plate portion has become a major problem.

[Problem that the invention seeks to solve]

The present invention solves the above-mentioned problems of conventionally known honeycomb structures, and provides a composite structure having a honeycomb structure that does not cause peeling between the core part and the flat plate part and can be manufactured by a simple manufacturing process. The purpose is to provide a special three-dimensional structure for materials.

[Means for solving problems]

The object of the present invention is to provide a three-dimensional knitted fabric consisting of two ground textures on the front and back sides and connecting yarns connecting the ground textures, in which the number of connection points Lp per square inch is the number of loops per square inch or the warp and weft. For the number of intersection points Tp, 0.05≦
In the area where Lp /Tp ≦0.8 is satisfied and where no connecting part is formed, an independent space is formed surrounded by the two ground textures on the front and back sides and connecting threads, and the size of the independent space is the non-connecting point. This is achieved by a three-dimensional knitted fabric characterized by satisfying 3≦Np≦500 when the number is Np.

In other words, the special three-dimensional structure according to the present invention is a three-dimensional structure made of a fiber aggregate knitted and woven by a warp knitting machine or a double loom having a double-row needle bed. This is obtained by supplying a connecting yarn that connects the ground yarn and the ground weave. Conventionally, structures with double structures obtained with warp knitting machines or double looms with double needle beds are not used industrially as they are; instead, the joints of the double structure are cut open and the connecting yarns are made into a pa-f shape. The velvet was made to stand up and was used for clothing, commonly known as velvet. However, the present inventors focused on the double structure before cutting it open, and discovered that by forming this double structure in a special shape, a three-dimensional knitted fabric suitable as a base material for composite materials could be obtained. We have arrived at the present invention.

The present invention will be described in detail below with reference to the accompanying drawings showing an embodiment of the three-dimensional knitted fabric according to the present invention.

A more detailed description of the present invention will be given below with reference to the accompanying drawings. FIG. 1 shows a model diagram of an embodiment of the present invention, and FIG. 2 is a side model diagram of a knitting section of a warp knitting machine having a double-row needle bed, which is one means for forming the three-dimensional knitted fabric of the present invention. shows. 1°2 in FIG. 1 is a two-dimensional structure of front and back fabrics, which is formed by supplying ground yarns 4 and 5 from a ground yarn reed 9 to knitting needles 8. Reference numeral 3 in FIG. 2 indicates a connecting portion by a connecting thread, which is formed by supplying the connecting threads 6 and 7 from the connecting thread liquid 10 to the knitting needle 8. In addition, in a double loom, two ground thread supply beams and a connecting thread supply beam are provided to form the ground textures on both the front and back sides, and the two ground textures on the front and back sides are knitted by the weft and connected by a predetermined texture. A three-dimensional fabric as illustrated in FIG. 1 can be obtained by connecting the threads to the wefts in the two ground textures on the front and back sides.

When the double-structured three-dimensional structure is used as a base material for a composite material, the number of connection points per square inch Lp is determined by the number of loops per square inch (in the case of knitted fabrics) or the number of warp/weft intersection points (in the case of woven fabrics). case) "t'0." for Tp.
It is important that 05≦Lp/Tp: 50.8 is satisfied. In the case of the warp knitted fabric shown in FIG. 3, the connection point here is the connection yarn 6 connected to the ground structure 1 on the front side forming a connection part 3 while connecting to the ground structure 2 on the back side. loops 13a and 13b, and similarly
Refers to the loops 11a and 11b connected to al. The number of connection points per square inch Lp refers to the number of connection points that exist per square inch in the ground structure on either the front side or the back side. Therefore, as a three-dimensional knitted fabric, there are similar connection points on the front and back sides,
There will be 2XLp connection points per square inch. On the other hand, the number of loops per square inch 'rp means the number of loops per square inch at any part on the front side or back side when forming the three-dimensional knitted fabric of the present invention with a knitting machine,
The number of warp/weft intersection points 'rp is an expression when forming the knitted fabric of the present invention on a loom, and is expressed as the product of the number of warp threads and the number of weft threads per square inch.

FIG. 4 shows an example of a model diagram of the ground texture for a knitted fabric per square inch. In this example, connection point 11
The number of loops Lρ is 27, and the number of loops Tp is 84. - Figure 5 shows an example of a model diagram of the ground texture for a fabric per square inch. In this example, the number Lp of connection points 11 is 27, and the number Tp of loops is 169.
It is individual.

In this specification, the unconnected points are i2a in FIG.
As shown by 12b, 12c, 14a, 14b, and 14c, these are points where the connecting yarn 6 does not form a connecting part with the other side's ground structure. More specifically, non-connection points refer to points 12a, 12b, and 12c where the connecting yarn 6 does not form the connecting portion 3 but forms a ground weave together with the ground yarn, and also refers to points 12a, 12b, and 12c where the connecting yarn 6 does not form the connecting portion 3. 14a when a loop of the ground weave is formed only with the ground thread without any fabric.

14 b and 14 c. Furthermore, the ground structure formed by the ground yarn in the case where the connecting thread 6 is inserted into either the ground structure 1 or 2 without forming the connection part 3 or when it floats between the ground structure 1 and 2. The loop is also included in the unconnected points. The number Np of unconnected points means the number of unconnected points forming one independent space when viewed from one of the ground structures.

In the three-dimensional knitted fabric according to the present invention, the number of connection points Lp
must satisfy the relationship 0.05≦Lp/Tp≦0.8 with respect to the number of loops per square inch or the number of warp/weft intersection points Tp, preferably 0.1≦Lp/T
It is preferable to select in the region of p≦0.4. Lp/Tp
>0.8, when a three-dimensional composite material such as a honeycomb structure is produced by applying a resin to the three-dimensional warp fabric according to the present invention, the resin does not penetrate into the entire connecting part and adheres in patches. Furthermore, even if the resin penetrates successfully, the result will be a three-dimensional +1.1 structure with no cavities, requiring a large amount of resin, increasing the weight of the composite material itself, and increasing manufacturing costs. On the other hand, when Lp /Tp < 0.05, there are too few connecting parts to support the two base Mi weaves, making it difficult to cure the resin while maintaining the three-dimensional shape. Furthermore, even after the resin is cured, the strength against compression is significantly reduced, resulting in poor product quality. Said 0.05≦≦Lp/Tp≦0
．． If the condition 8 is satisfied, the resin permeates into the connecting portions, and cavities are formed between the connecting portions after curing, so that the material strength hardly decreases and the weight can be significantly reduced. In addition, resin processing using the three-dimensional structure as a base material for composite materials is easier, the strength after resin processing is greater, and the weight can be reduced by 0.
More preferably, the range is 1≦Lp/Tp≦0.4.

Next, the three-dimensional knitted fabric of the present invention has a part where some of the connecting yarns do not connect the two base Mi weaves on the front and back sides, and in that part, the two base weaves on the front and back sides and the connecting yarns surrounding that part create an independent connection. A space is formed. Here, an independent space means a state in which the connecting point has a substantially polygonal shape when viewed from the ground texture, and adjacent hollow portions are always partitioned by connecting threads. To explain this using the example of Fig. 4, the connecting points 11 have a hexagonal shape in the ground texture, and one independent space is the connecting threads extending from the 10 connecting points forming the hexagon, and the connecting points 11 that form the hexagon. It refers to the part surrounded by two pieces of ground structure consisting of eight unconnected points inside a square. The present invention is characterized in that the number of unconnected points Np satisfies 3≦Np≦500 as the size of the independent space. The size of the independent space referred to here is expressed by the number of unconnected points in one polygon viewed from the ground structure, and the effect of the present invention can be achieved when the number is in the range of 3 to 500. In the case of Np<3, it is difficult to impregnate the resin, and even if it is successfully impregnated, the resin will penetrate into the cavity, making it heavy, increasing the amount of resin used, and increasing the cost. Also N+) >so.

In this case, one space becomes too large and it is difficult to process the resin while maintaining the three-dimensional shape, resulting in a decrease in compression resistance in that area. In this way, when the independent space is impregnated with resin and cured, it can have uniform strength as a three-dimensional composite material. If the space is a continuous space formed continuously in the longitudinal direction, latitudinal direction, or diagonal direction, parts of weak strength will occur continuously in the material, and fracture will occur from this part, making it impossible to use as a composite material. I can't stand it. The yarn forming the three-dimensional knitted fabric of the present invention is not particularly limited. However, for example, it is effective to form the front and lining structures from thermoplastic synthetic fibers and carbon fibers, aramid fibers, or ceramic fibers, and to use carbon fibers, aramid fibers, or ceramic fibers for the connecting threads.

〔Example〕

An embodiment of the three-dimensional object 11a of the present invention was formed according to the knitting pattern shown in FIG. 6 using a warp knitting machine having a double-row needle bed shown in FIG. 2 and six reeds.

L+ and Lz are ground yarn layers used to form the front side ground weave, and Ls and L6 are ground yarn layers used to form the back side ground weave. For the front and lining structure, the threads were completely packed against the reed in order to densely layer the threads. Also Li.

L4 is a reed for connecting threads, and the threads were set in a 1-in, 7-out state. When Ls and L4 were formed to have a symmetrical structure as shown in FIG. 3, it was possible to form a three-dimensional honeycomb structure in which a honeycomb core shown in FIG. 1 was sandwiched between two flat plates. The obtained three-dimensional knitted fabric has Lp = 160
, Tp-860 and Lp/Tp-0.18.

The number of unconnected points forming one independent space is Np
When the resulting three-dimensional knitted fabric was impregnated with a thermosetting resin, the resin successfully penetrated into the joints.

The resin was further cured to obtain a fiber-reinforced composite material. Test pieces measuring 4 inches vertically and 1 inch horizontally were collected from the resulting composite material in the course direction and in the ale direction, and a three-point bending test as shown in Figure 7 was conducted. The ratio was 1.1, indicating relatively excellent isotropy.

For comparison, a three-dimensional knitted fabric was formed by setting the yarn in the connecting yarn liquid of L3°L4 with one fin out using the knitting structure shown in FIG. When impregnated with a synthetic resin, it was difficult to uniformly infiltrate the connecting portion with the resin.

Also, set the connecting thread on the reed with 1 in and 28 out,
A three-dimensional knitted fabric having a honeycomb structure shown in FIG. 1 was formed, and the obtained three-dimensional knitted fabric had Lp /Tp = 0.04,
In this case, when the two substrates were in contact with each other and impregnated with resin, it was difficult to maintain the three-dimensional structure and harden the material.

Furthermore, the connecting yarn was set in a reed in a 1-in-7-out state to obtain a three-dimensional w1 fabric having the shape shown in FIG.

Although the three-dimensional knitted fabric had Lp /Tp = 0.14, it did not have an independent space, so after resin impregnation and curing, a three-point bending test as shown in Figure 7 was performed on test pieces in the course direction and wale direction. As a result, the fracture strength ratio was 0.2, and the fracture strength in the course direction was extremely low.

〔Effect of the invention〕

The three-dimensional knitted fabric according to the present invention is formed on a knitting machine or a loom,
Moreover, since the connecting yarn is firmly connected to the two base structures, there is no separation between the core part and the flat plate part as in the conventional case, and a three-dimensional composite material can be manufactured simply by impregnating the three-dimensional knitted fabric of the present invention with a resin or the like. , there is no need to use conventional complicated and diverse processes.

Furthermore, the three-dimensional knitted fabric of the present invention has an independent space at the connecting portion, which reduces the weight and also reduces the amount of resin used. Furthermore, when it is made into a composite material, it has the advantage that the strength of the material is uniform with no unevenness.

[Brief explanation of the drawing]

FIG. 1 is a model diagram of an embodiment of the three-dimensional knitted fabric of the present invention. FIG. 2 is a model diagram of the side surface of the knitting section of a warp knitting machine having a double needle bed as a means for forming the three-dimensional knitted fabric of the present invention. FIG. 3 is an enlarged view of a model of one loop row in an embodiment of the three-dimensional knitted fabric of the present invention. Figure 4 is a model diagram of the texture shape obtained by the knitting machine. FIG. 5 is a model diagram of the ground texture shape obtained by the loom. FIG. 6 shows an example of the &I organization chart forming the three-dimensional knitted fabric of the present invention, and FIG. 7 shows an example of a destructive test of the composite material. FIG. 8 shows a model diagram of a three-dimensional knitted fabric formed for comparison. 1.2...ground structure, 3...connection part, 4.5.
... ground thread, 6,7... connecting thread, 8... knitting needle, 9... flow for ground thread, 10... liquid for connecting thread, 11.13... connecting point, 12, 14
...Unconnected point, P...Pressure, C...Course direction, W...Wale direction.

Claims (1)

[Claims] A three-dimensional knitted fabric consisting of two ground weaves on the front and back sides and a connecting yarn that connects the ground weaves, in which the number of connection points Lp per square inch is relative to the number of loops per square inch or the number of warp and weft crossing points Tp. , 0.05≦Lp/Tp≦0.8
In the area where the connecting part is not formed, an independent space is formed surrounded by the front and back two ground textures and the connecting thread, and the size of the independent space is 3 when the number of unconnected points is Np. A three-dimensional knitted fabric characterized by satisfying ≦Np≦500.