JP2019026949A - Knitted fabric base material for frp - Google Patents

Abstract

CONSTITUTION: A knitted fabric base material for FRP comprises a plurality of layers comprising parallel reinforcing fiber yarns fixed by a knitting yarn. An arrangement pitch, an arrangement direction, a thickness of the reinforcing fiber yarns or the number of the layers of the reinforcing fiber yarns are varied depending on a position in the base material to realize an intensity distribution necessary for the base material.EFFECT: It is possible to obtain a knitted fabric base material for FRP with varied strength or thickness depending on a position in accordance with an FRP product.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a knitted fabric base material for FRP (fiber reinforced plastic).

  The applicant has proposed a knitted fabric in which warp yarns and inlay yarns (weft yarns) are inserted (Patent Document 1 JP2013-40411A). Inserting a warp into a knitted fabric is more difficult than inserting an inlay yarn. Therefore, the applicant has proposed that the warp is actively fed toward the mouth of the knitting machine by a power roller, and an air flow is blown into a pipe through which the warp is passed, and the warp is inserted into the knitted fabric by the air flow ( Patent Document 2 JP2015-48536A).

  Patent Document 3 (WO97 / 21860A) and Patent Document 4 (JPH02-259144A) disclose a knitted fabric in which a plurality of types of reinforcing fiber yarns are inserted. Patent Document 3 (WO97 / 21860A) describes that the periphery of a void is reinforced with warp and inlay yarns. However, Patent Document 3 does not describe that a knitted fabric is used as an FRP base material, and forces such as tension, compression, and twist that act on the final FRP product are taken into consideration. Patent Document 4 (JPH02-259144A) describes a triaxial knitted fabric in which two kinds of bias yarns arranged obliquely with respect to the warp are inserted in addition to the warp. The axis is the direction in which the reinforcing fiber yarns are arranged, and is also the direction in which the substrate has strength.

JP2013-40411A JP2015-48536A WO97 / 21860A JPH02-259144A

  The final FRP product manufactured from the FRP knitted fabric base material requires different strength depending on the location. However, this is not taken into account in the prior art. Patent Document 3 reinforces the periphery of the gap, but the structure of the FRP knitted fabric base material is not determined according to the strength distribution required for the entire FRP product.

  The subject of this invention is providing the knitted fabric base material for FRP suitable for FRP products from which intensity | strength or thickness differs according to a place.

  In the knitted fabric base material for FRP of the present invention, a plurality of layers composed of parallel reinforcing fiber yarns are fixed by knitting yarns, and the arrangement pitch, arrangement direction, thickness of the reinforcing fiber yarns, or the number of layers of reinforcing fiber yarns The strength of the base material is changed according to the position by changing according to the position in the base material.

  When the arrangement pitch, arrangement direction, thickness, or number of layers of reinforcing fiber yarns changes, the strength or thickness of the base material also changes. As a result, the strength or thickness of the substrate can be changed according to the strength or thickness at each location required for the FRP product.

  In this invention, the directions of the reinforcing fiber yarns are basically parallel in one layer, and the strength of the base material is changed in units of layers. For this reason, a substrate having a desired strength distribution can be easily knitted. In addition, in order to provide the hole etc. for letting a pipe pass, changing the arrangement | positioning of a reinforced fiber yarn locally is not excluded.

  When the arrangement pitch of the reinforcing fiber yarns is changed in the substrate, the density at which the reinforcing fiber yarns are arranged changes and the strength also changes. When the arrangement direction is changed, the directionality of the strength of the base material can be changed.

  The arrangement direction and the number of layers can be changed simultaneously. For example, it is assumed that reinforcing fiber yarns are arranged in two layers in the longitudinal direction and the short side direction (course direction in knitting). Then, a base material has high intensity | strength in the biaxial direction which consists of the arrangement direction in these two layers, and intensity | strength is low in the diagonal direction of those. In this invention, the direction of the reinforcing fiber yarns in the longitudinal direction is changed to an oblique direction, and one layer in which the reinforcing fiber yarns are arranged in the longitudinal direction is divided into a layer arranged in the longitudinal direction, a layer arranged in the oblique direction, etc. It can be changed from the middle of the material. Further, the layers arranged in the oblique direction can be two layers from the lower right to the upper left and the lower left to the upper right along the longitudinal direction. Then, the two layers can be changed to four layers according to the position of the base material, and the direction of high strength can be changed from two axes to four axes according to the position within the base material. Not limited to the layer in which the reinforcing fiber yarns are arranged in the longitudinal direction, the layer arranged in the short side direction is changed to a total of three layers, for example, two layers in which the reinforcing fiber yarns are arranged obliquely and one layer in the short side direction. Can be made. Moreover, the layer changed into multiple layers, such as 3 layers, can be returned to 1 layer etc. according to the position of the longitudinal direction in a base material.

  The thickness and the number of layers of the reinforcing fiber yarn greatly change the strength of the base material. In order to change the thickness, the yarn feeder for supplying the reinforcing fiber yarn may be changed during knitting. The number of layers can be changed in the same way, but as described above, the number of layers can be changed by dividing one layer into multiple layers with different arrangement directions and combining multiple layers with different arrangement directions into one layer. Can do.

  When the thickness of the reinforcing fiber yarn is changed or the number of layers is changed, the thickness can be changed according to the position of the substrate. Even if the arrangement pitch of the reinforcing fiber yarns is changed, the thickness can be changed according to the position of the substrate. In addition to these, the thickness can be changed by stacking the substrates. However, if the thickness is changed during knitting of the substrate, the thickness can be changed from the beginning in accordance with the desired thickness shape.

The use of the FRP knitted fabric base material is arbitrary, but preferably the FRP knitted fabric base material has a wing shape,
A warp yarn is arranged along the longitudinal direction of the wing shape, and an inlay yarn is arranged along a direction perpendicular to the longitudinal direction,
The warp or inlay yarn at the base end of the wing shape becomes a bias yarn that crosses the warp diagonally at the tip of the wing shape,
The warp yarn, inlay yarn, and bias yarn are made of reinforcing fiber yarns,
The base end of the wing shape includes at least a warp layer and an inlay yarn layer,
The tip of the wing shape includes a warp layer, an inlay yarn layer, and at least two bias layers opposite to each other in the direction crossing the warp.

  The wing shape is insufficient in twisting strength with only warp and inlay yarns, but when the warp or inlay yarn is changed to a bias yarn, the strength against twisting is improved. Since the bias yarn has at least two layers in which the direction of crossing with the warp is reversed, it has high strength against twisting to either side with the warp direction (longitudinal direction of the base material) as an axis. The tip portion is at least four layers of a warp layer, an inlay yarn layer, and two or more bias yarn layers. On the other hand, the base end portion where the strength is not so required is at least two layers of a warp layer and an inlay yarn layer. Since the FRP knitted fabric base material can be knitted into an arbitrary shape in plan view, it can be shaped according to the wing.

  Preferably, in the cross section perpendicular to the longitudinal direction of the FRP knitted fabric base material, the length of the layers at both ends in the thickness direction along the width direction of the base material compared to the layer at the central part in the thickness direction of the base material Increase the length. If it does in this way, the edge part of a layer will become inconspicuous along the width direction of a base material, and the surface of a base material will become smooth. This is important, for example, in reducing the resistance of the wing.

  Preferably, the number of layers of reinforcing fiber yarns at the base end portion of the wing shape is larger than the number of layers of reinforcing fiber yarns at the tip portion of the wing shape, and the base end portion of the wing shape is thicker than the tip portion. . In general, a wing is required to have a thick base end portion attached to a boss or the like and a thin tip end portion, and an FRP knitted fabric base material satisfying this requirement can be obtained.

  Examples of wing shapes include gas turbines, compressors, blower wings, ship or aircraft propellers, wind power blades, small aircraft main wings, and auxiliary wings. Gas turbines, compressors, fan blades, ship or aircraft propellers, wind power blades, and the like are impeller or rotor blades. The wing shape means a shape of a wing of an aircraft or the like and a blade of an impeller or a rotor.

  Preferably, a single FRP knitted fabric base material has a blade shape also in the thickness direction of the blade. In this case, it is not necessary to laminate the FRP knitted fabric base material, and the manufacture of the wing becomes easy.

  Preferably, the FRP knitted fabric base material is configured to have a blade shape when stacked in the thickness direction of a plurality of blades. In this case, since the thickness does not increase, the knitting of the FRP knitted fabric base material becomes easy.

  Preferably, the arrangement pitch of the reinforcing fiber yarns (inlay yarns) perpendicular to the longitudinal direction of the FRP knitted fabric base material changes along the longitudinal direction. Thereby, the intensity | strength of a base material can be changed along a longitudinal direction.

  Preferably, the number of reinforcing fiber yarns passing through a cross section perpendicular to the longitudinal direction of the FRP knitted fabric base material varies along the longitudinal direction. Thereby, the intensity | strength of a base material can be changed along a longitudinal direction.

  Preferably, the FRP knitted fabric base material includes a region included in the FRP product and a region not included in the FRP product, and the density of the reinforcing fiber yarn in the region included in the FRP product (for example, the reinforcing fiber per area). The number of yarns) is made higher than the density of reinforcing fiber yarns in the area not included in the FRP product. If it does in this way, while reinforcing the required part of the FRP knitted fabric base material, a reinforced fiber yarn can be used effectively.

Cross-sectional view in the transverse direction showing the structure of the FRP knitted fabric substrate of the example The figure which shows typically the knitting method of the knitted fabric base material for FRP of an Example. Cross section in the transverse direction of a long FRP knitted fabric base material consisting of warp yarns and two bias yarns A diagram schematically showing changing a part of warp yarn and inlay yarn to bias yarn in the FRP knitted fabric base material The figure which shows the structure of the knitted fabric base material for FRP where there are few surface level differences The figure which shows the example of the knitted fabric base material for FRP which has few steps of the surface and has desired cross section shape The figure which shows the knitted fabric base material for FRP where thickness and strength differ depending on the place by adjusting the density of the warp yarn and the range where the bias yarn is arranged The density and thickness of the warp yarns vary depending on the location, and the knitted fabric base material for FRP with increased strength and density at the center in the width direction by allocating the bias yarn in the center in the width direction is schematically shown. Illustration Diagram showing wing-shaped FRP knitted fabric base material The figure which shows the knitted fabric base material for FRP for helmets typically The figure which shows a box-shaped FRP knitted fabric base material typically

  In the following, an optimum embodiment for carrying out the invention will be shown.

  The Example of the knitted fabric base material for FRP is shown in FIGS. Fig. 1 shows the basic structure of the FRP knitted fabric base material 2, wherein 3 is a warp, 4 is an inlay yarn (weft), 5 and 6 are bias yarns, and bias yarns 5 and 6 are longitudinal and horizontal directions. Inclined from. The vertical direction of the substrate 2 is a direction perpendicular to the drawing, the horizontal direction is the horizontal direction of the drawing, the bias yarn 5 is inclined so that the right side of the drawing is above the drawing, and the bias yarn 6 is on the left side of the drawing. It inclines so that it may become above a drawing.

  8 is a knitting yarn which is knitted by a knitting machine to form a stitch 10 and a transition yarn 9. The crossover yarn 9 penetrates the FRP knitted fabric base material 2 and connects the front and back of the base material 2, and a part of the crossover yarn 9 stops the back surface of the warp yarn 3 when viewed from the stitch 10 side. A plurality of stitches 10 are connected in a direction perpendicular to the drawing (longitudinal direction), and the rows of the stitches 10 are different in direction from the inlay yarn 4 and the bias yarns 5 and 6. Then, the warp 3, the inlay yarn 4, and the bias yarns 5 and 6 are fixed by the stitch 10 and the crossover yarn 9.

  In the embodiment, the warp yarn 3 is fixed by the cross yarn 9, but the bias yarn 5 or 6 may be fixed. Similarly, although the inlay yarn 4 is fixed by the stitch 10, the bias yarn 5 or 6 may be fixed. Further, the number of layers of the warp yarn 3, the inlay yarn 4, and the bias yarns 5 and 6 arranged between the stitch 10 and the cross yarn 9 is arbitrary, and is four in FIG.

  The warp yarn 3, the inlay yarn 4, and the bias yarns 5 and 6 are reinforced fiber yarns, and the materials are, for example, carbon fiber yarns, glass fiber yarns, and aramid fiber yarns. A carbon fiber yarn and a glass fiber yarn that are difficult to bend and have high strength are suitable for the warp yarn 3, and an aramid fiber yarn that is easily bent is suitable for the inlay yarn 4. The inlay yarn 4 is not limited to an aramid fiber yarn but may be a carbon fiber yarn or glass fiber. The bias yarns 5 and 6 may be any reinforcing fiber yarn. In the examples, unless otherwise specified, carbon fiber yarns are used for the warp yarn 3 and the bias yarns 5 and 6, an aramid fiber yarn is used for the inlay yarn 4, and the bias yarn 5 that is required to be folded at the lateral end of the substrate. , 6 uses a carbon fiber yarn thinner than the warp yarn 3. The knitting yarn 8 is a yarn that can be knitted to form a knitted fabric, such as nylon or polyester.

  In each embodiment, a plurality of reinforcing fiber yarns of the same material and having the same thickness are arranged in parallel in the same direction. A plurality of reinforcing fiber yarns parallel in the same direction is regarded as one element, and this is called one axis or one layer. For example, the FRP knitted fabric substrate 2 in FIG. 1 has four axes, and in each embodiment, the number of axes is two or more. That is, the four axes of the warp 3, the inlay yarn 4, and the bias yarns 5 and 6 are not essential, and may be, for example, two axes or five axes or more. In the FRP knitted fabric base material, the direction of the warp 3 (same as the direction in which the stitches 10 are connected vertically) is referred to as the longitudinal direction, and the direction of the inlay yarn 4 (same as the direction in which the knitting yarn 8 extends) is referred to as the lateral direction. The vertical direction is the wale direction during knitting, and the horizontal direction is the course direction during knitting.

  FIG. 2 shows a knitting method of the base material 2, and the knitting machine used is a flat knitting machine or a circular knitting machine, and is provided with a pair of front and back needle beds 11, 12, for example. The knitting yarn 8 is supplied from a carrier 14, the warp yarn 3 is supplied from a fixed or movable carrier (not shown), and the bias yarns 5 and 6 and the inlay yarn 4 are supplied from a movable carrier (not shown). Further, if the knitting machine is provided with a cutter that cuts the warp yarn 3, the inlay yarn 4, and the bias yarns 5 and 6, the reinforcing fiber yarn that is no longer used for knitting the base material 2 can be cut during knitting. This facilitates the process of reducing the number of axes during knitting. If these yarns are removed from the FRP knitted fabric base material during knitting without providing a cutter, free warp yarns, inlay yarns, or bias yarns that are not inserted into the FRP knitted fabric base material are generated.

  The stitches 10 are formed by the needles of the needle bed 11, and the carrier 14 moves on the side opposite to the needle bed 11 when viewed from the base material 2. Then, the crossover yarn 9 is arranged so as to penetrate the base material 2 on the front and back sides. For the knitting yarn 8, the warp yarn 3, the inlay yarn 4, and the bias yarns 5 and 6 of the base material 2 are fixed together, and the knitting method using the knitting yarn 8 is arbitrary. In the case of a circular knitting machine, the inlay yarn and the bias yarn are spirally incorporated into the substrate. On the other hand, in the case of a flat knitting machine, the inlay yarn is folded back at the end of the knitting width, and the bias yarn is folded back at a desired position.

  FIG. 3 shows a triaxial FRP knitted fabric base material 22 composed of warp yarns 3 and bias yarns 5 and 6, and no inlay yarn 4 is provided. The base material 22 has a long shape without the inlay yarn 4 being folded back. Depending on the location, the number of axes or the reinforcing fiber yarn arrangement pitch on each axis, the thickness of the reinforcing fiber yarn, the material, etc. are changed, and the strength distribution or thickness depending on the location in the FRP knitted fabric substrate It is set as the base material provided with.

  The warp yarn or the inlay yarn can be changed to a bias yarn during the knitting of the FRP knitted fabric base material. Conversely, the bias yarn can be changed to the warp yarn or the inlay yarn during the knitting of the FRP knitted fabric base material. Although FIG. 4 shows an example in which a part of the warp is changed to the bias yarn in the middle of knitting, all the warps can be changed to the bias yarn. It is also possible to change only part of the bias yarn to warp. Such an FRP knitted fabric base material 32 is shown in FIG. The reinforcing fiber yarns 35 and 36 are inserted into the base material 32 as warps by fixing the carrier halfway, and are inserted as bias yarns by moving the carrier in the course direction from the middle. The reinforcing fiber yarn 34 is initially arranged in the course direction and inserted as an inlay yarn, and is arranged obliquely in the course direction (lateral direction) and the wale direction (longitudinal direction) from the middle, and is inserted as a bias yarn. Since the knitting is performed by the flat knitting machine, the inlay yarn 4 and the bias yarns 5 and 6 are folded back by the folding portion 38, and the frequency of folding is the maximum for the inlay yarn 4 and less for the bias yarns 5 and 6.

  Contrary to FIG. 4, the bias yarn can be changed to a warp yarn or an inlay yarn during the knitting of the FRP knitted fabric base material. For these, reinforcing fiber yarns may be supplied from a movable carrier. When the carrier is fixed, the reinforcing fiber yarn becomes a warp. When the carrier is moved little by little, such as one stitch per several courses, it becomes a bias yarn, and when it is moved at a constant speed with the carriage of a flat knitting machine or a circular knitting machine, it becomes an inlay yarn.

  FIG. 5 shows an FRP knitted fabric base material 40 with few surface steps. The outer layer (outer shaft) of the substrate 40 has a longer lateral length, and the inner layer (inner shaft) has a shorter lateral length. When the outermost layers 41 and 41 in FIG. 5 are brought close to each other, the outermost layers 41 and 41 cover the surface of the base material 40, and no noticeable steps are generated. In FIG. 5, the inner layer is arranged symmetrically with respect to the base material 40, but it may be asymmetrical in accordance with the shape of the final FRP product. In FIG. 5, the outermost layer 41 is an inlay yarn layer, but it may be a warp yarn layer or a bias yarn layer.

  In the FRP knitted fabric base material 42 of FIG. 6, as in FIG. 5, the outermost layer is made the longest in the lateral direction so that the steps are not noticeable. The base material 42 is thin on the right side and thick on the left side, and has a shape close to the cross section of the wing. Although the base material 42 does not have a complicated shape such as twisting, a final shape such as twisting can be imparted by setting it in a mold and injecting resin into the mold and curing it.

  The knitted fabric base material for FRP is required to have a shape close to that of the final FRP product and to have the required strength at the necessary locations, and the machine parts such as blades have the desired density distribution. It is also required. For example, in the case of a wing or the like, the reinforcing fiber yarns are arranged along the longitudinal direction of the FRP knitted fabric substrate 52 so that the arrangement pitch of the reinforcing fiber yarns perpendicular to the longitudinal direction is small at the proximal end portion and large at the distal end portion. Change the pitch. Further, the number of reinforcing fiber yarns passing through a cross section perpendicular to the longitudinal direction is changed along the longitudinal direction with a wing or the like so as to increase at the proximal end portion and decrease at the distal end portion. Thereby, the mass of the front-end | tip part of a wing | blade can be made small compared with the mass of a base end part. In order to satisfy these requirements, the number of layers (number of axes) can be changed depending on the location, and at least one of the type, thickness, and arrangement pitch of the reinforcing fibers can be changed depending on the location. The strength of the reinforcing fiber is the highest for the carbon fiber, and the glass fiber and the aramid fiber are lower than the carbon fiber.

  In the FRP knitted fabric substrate 52 of FIG. 7, the bias yarns 5 and 6 are arranged on the left side of the drawing in a wider range than the right side, and the pitch of the warp yarns 3 is reduced on the left side of the drawing. As a result, since the bias yarn layer is not on the right side, the left side is thick and strong. Further, the left side has a bias yarn layer, so that it is strong against twisting. The right side is thin and the strength is low.

  In the FRP knitted fabric substrate 62 of FIG. 8, thin warps 63 are arranged at a large pitch at both ends in the lateral direction, and thick warps 3 are arranged at a small pitch at the center. Further, the bias yarns 5 and 6 are intensively arranged at the center in the horizontal direction in the figure, and are not arranged at both ends in the horizontal direction. For these reasons, the FRP knitted fabric base material 62 has a thick central portion in the horizontal direction and high strength, and both end portions in the horizontal direction are thin and low in strength.

  FIG. 9 shows an FRP knitted fabric substrate 72 for a wing, such as a gas turbine, a compressor, a blower wing, a ship or aircraft propeller, a wind power blade, a main wing of a small aircraft, an auxiliary wing, and the like. Gas turbines, compressors, fan blades, ship or aircraft propellers, wind power blades, and the like are impeller or rotor blades. The wing shape means a shape of a wing of an aircraft or the like and a blade of an impeller or a rotor. In the example in the upper part of the figure, the FRP knitted fabric base material 73, 74 composed of four layers from the wing-shaped leading end portion to the base end portion, and the FRP knitted fabric base material of two or four layers, etc. Organize 75. In the left side region 76, the base materials 73 and 74 have, for example, a total of four axes including two vertical and horizontal axes and two bias yarns, and the rigidity against torsion is increased by increasing the number of axes. That is, when the two axes of the bias yarn are added to the vertical and horizontal axes, the rigidity against bending increases, and the rigidity against twisting also increases. In the region 77 that becomes the base of the wing and is accommodated in a boss and is difficult to apply bending stress or the like, the bias yarn is changed to warp yarn or inlay yarn and knitted biaxially. Further, the thickness of the region 77 is increased by increasing the number of warp layers or the number of inlay yarns so as to facilitate fixing to the boss. For this reason, in the region 77, a carrier such as a warp or inlay yarn is added to increase the number of warp or inlay yarn layers.

  The FRP knitted fabric base material can appropriately control the position at which the reinforcing fiber yarn is inserted into the knitted fabric, and can also appropriately control the position at which the insertion of the reinforcing fiber yarn is stopped. For this reason, the FRP knitted fabric base material can be knitted into an almost arbitrary shape in plan view. In the case of a wing, the tip is arcuate and the side edges are also curvilinear. Then, the FRP knitted fabric base materials 73 and 74 are knitted in such a shape. For example, the FRP base material 75 is folded back at the center in the longitudinal direction, and the FRP base materials 73 and 74 are stacked on the top and bottom of the folded base material 75 to form an FRP knitted fabric base material 72 having a wing shape. This is set in a mold and heated to disassemble the knitting yarn. What is necessary is just to change about the temperature of a heating according to the raw material of the knitting yarn to be used. Also, impregnate the base material with resin before setting it into the mold, or inject the resin inside the mold to make a FRP product with wing shape. The wing has a complicated cross-sectional shape, and a desired cross-sectional shape is given by setting the base material 72 in a mold and deforming the base material 72 along the mold.

  In the lower FRP base material 78 of FIG. 9, the number of reinforcing fiber yarns is greater than four, or the reinforcing fiber yarns are thicker than the FRP base material 72. One base material 78 is knitted so as to have the shape of the lower part of FIG. 9 in a plan view and the shape of the middle part of FIG. 9 in a side view. The FRP substrate 78 is similarly set in a mold and processed in the same manner.

  FIG. 10 shows an FRP knitted fabric base material 82 for a helmet, and the shape after molding with a mold is hemispherical. If the circular region 84 becomes a helmet and the planar base material 82 is hemispherical, the interval between the reinforcing fibers is increased, the density is lowered, and the strength is insufficient. A portion around the circular region 84 of the FRP knitted fabric base material 82 is a region not included in the FRP product. Therefore, warp 85 and inlay yarn 86 are added to region 84. In the figure, ▲ indicates a position where the inlay yarn is introduced, and △ indicates a position where the inlay yarn is not inserted into the base material. The carrier of the inlay yarn is movable, the carrier that has been waiting outside the base material 82 is moved into the base material 82, and the inlay yarn 86 is inserted into the base material 82 at the position ▲. The carrier is moved out of the base material 82 at the position Δ, and the inlay yarn 86 is cut with a cutter or the like. The carrier of the inlay yarn 86 may wait from the beginning in the base material 82, and the carrier may be retained in the base material 82 after the inlay yarn 86 is cut. Further, a free inlay yarn may be formed between the position of Δ and the carrier without cutting the end portion of the inlay yarn 86.

  In order to add the warp 85, for example, the carrier of the warp waiting on the outside of the base material 82 is moved into the base material 82, and the base material is warped near the end of the region 84 by, for example, a power roller and an air flow. Insert into 82. When the knitting of the region 84 is finished, the power roller and the air flow are stopped, and the insertion of the warp 85 is stopped. For example, the end of the warp 85 is cut by a cutter, and the carrier of the warp 85 is moved to the outside of the base material 82. Also in the case of the warp 85, the carrier may wait in the base material 82 from the beginning, and the carrier may be retained in the base material 82 even after the end portion is cut. Therefore, the carrier of the warp 85 may be a fixed carrier. Further, a free warp may be generated without cutting the end of the warp 85. Thus, in the FRP knitted fabric base material, the density of the reinforcing fiber yarn is higher in the region included in the FRP product than in the region not included in the FRP product.

  FIG. 11 shows a box-shaped FRP knitted fabric base material 92. 93 and 94 are fold lines corresponding to the edges of the box. By connecting the edge 95a to the edge 96a, the edge 95b to the edge 96b, the edge 97a to the edge 98a, and the edge 97b to the edge 98b, the substrate 92 has a box shape. Note that the edge 95a, the edge 96a, and the like are connected by turn back knitting. In the turn-back knitting, for example, the knitting is performed in order from the bottom to the top of FIG. Next, a new stitch is formed on the stitches of the edges 95a and b to widen the knitting width. Further, the warp yarn and the bias yarn passing through the edges 95a and b are left as they are until the edge 96b is knitted. Similarly, the edges 97a and b are connected to the edges 98a and b.

  The inlay yarn and warp yarn are inserted on the entire surface of the base material 92, but the fold lines 93 and 94 are easily deformed by external force. Therefore, the reinforcing fibers are inserted into the region 100 around the fold line 93 and the region 101 around the fold line 94 to add warp yarns, inlay yarns, and the like, thereby increasing the strength compared to the other regions. The movement of the carrier and the cutting of the extra inlay yarn and warp yarn are the same as in the embodiment of FIG.

2,22,32,40,42,52,62 FRP knitted fabric base material
3,63 warps
4,34 Inlay yarn
5,6,35,36 Bias yarn
8 Knitting yarn
9 Crossover yarn
10 stitch
11, 12 needle bed
14 Career
38 Folding part
41 Outermost layer
43 layers
72-75 FRP knitted fabric base material
76,77 areas
78,82 FRP knitted fabric base material
84 areas
85 Warp
86 Inlay yarn
92 FRP knitted fabric base material
93,94 fold line
95a to 98b
100,101 areas

Claims (11)

  In the FRP knitted fabric base material in which a plurality of layers composed of parallel reinforcing fiber yarns are fixed by knitting yarns, the arrangement pitch, the arrangement direction, the thickness of the reinforcing fiber yarns, or the number of layers of reinforcing fiber yarns is A knitted fabric base material for FRP, wherein the strength of the base material changes according to the position by changing according to the position in the base material.   The knitted fabric base material for FRP according to claim 1, wherein the thickness of the reinforcing fiber yarn or the number of layers of the reinforcing fiber yarn varies depending on the position in the base material.   The knitted fabric base material for FRP according to claim 1 or 2, wherein the thickness changes according to the position in the base material. The knitted fabric base material for FRP has a wing shape,
A warp yarn is arranged along the longitudinal direction of the wing shape, and an inlay yarn is arranged along a direction perpendicular to the longitudinal direction,
The warp or inlay yarn at the base end of the wing shape becomes a bias yarn that crosses the warp diagonally at the tip of the wing shape,
The warp yarn, inlay yarn, and bias yarn are made of reinforcing fiber yarns,
The base end of the wing shape includes at least a warp layer and an inlay yarn layer,
The tip portion of the wing shape includes a warp layer, an inlay yarn layer, and at least two bias layers opposite to each other in a direction crossing the warp. One of FRP knitted fabric base material.   In the cross-section perpendicular to the longitudinal direction of the FRP knitted fabric base material, the layers at both ends in the thickness direction have a longer length in the width direction of the base material than the layer at the central part in the thickness direction of the base material. The knitted fabric base material for FRP according to any one of claims 1 to 4, wherein:   The number of layers of reinforcing fiber yarns at the base end portion of the wing shape is larger than the number of layers of reinforcing fiber yarns at the tip portion of the wing shape, and the base end portion of the wing shape is thicker than the tip portion. The knitted fabric base material for FRP according to claim 4.   The knitted fabric substrate for FRP according to any one of claims 1 to 6, wherein the arrangement pitch of the reinforcing fiber yarns perpendicular to the longitudinal direction of the knitted fabric substrate for FRP varies along the longitudinal direction.   The knitted fabric for FRP according to any one of claims 1 to 7, wherein the number of reinforcing fiber yarns passing through a cross section perpendicular to the longitudinal direction of the knitted fabric substrate for FRP varies along the longitudinal direction. Base material. The knitted fabric base material for FRP comprises a region included in the FRP product and a region not included in the FRP product,
The density of the reinforcing fiber yarn in the region included in the FRP product is higher than the density of the reinforcing fiber yarn in the region not included in the FRP product. Either FRP knitted fabric base material.   The FRP knitted fabric base material according to claim 4, wherein one FRP knitted fabric base material has a wing shape in the thickness direction of the wing.   The FRP knitted fabric base material according to claim 4, wherein the FRP knitted fabric base material is configured to have a wing shape when stacked in the thickness direction of a plurality of blades.

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