JP7000061B2 - Knitted fabric base material for FRP - Google Patents

Description

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

The applicant proposed a knitted fabric into which a warp and an inlay yarn (weft) were inserted (Patent Document 1 JP2013-40411A). Inserting the warp into the knitted fabric is more difficult than inserting the inlay yarn. Therefore, the applicant proposed to positively send the warp toward the tooth opening of the knitting machine by a power roller, blow an air flow into the pipe through which the warp was passed, and insert the warp 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 into which a plurality of types of reinforcing fiber yarns are inserted. Patent Document 3 (WO97 / 21860A) describes that the circumference of the void is reinforced by warp yarn and inlay yarn. However, Patent Document 3 does not describe that the knitted fabric is used as the base material of FRP and the force acting on the final FRP product, such as pulling, compressing, and twisting, is taken into consideration. Further, Patent Document 4 (JPH02-259144A) describes a three-axis knitted fabric in which two types of bias yarns arranged diagonally with respect to the warp yarns are inserted in addition to the warp yarns. The axis is the direction in which the reinforcing fiber threads are arranged, and is also the direction in which the base material has strength.

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

The final FRP product manufactured from a knitted fabric substrate for FRP requires different strengths from place to place. However, this is not considered in the prior art. In Patent Document 3, the circumference of the void is reinforced, but the structure of the knitted fabric base material for FRP is not defined in consideration of the strength distribution required for the entire FRP product.

An object of the present invention is to provide a knitted fabric base material for FRP suitable for FRP products having different strengths or thicknesses depending on the location.

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 the knitting yarns, and the arrangement pitch, arrangement direction, thickness, or number of layers of the reinforcing fiber yarns of the reinforcing fiber yarns is different. It is characterized in that the strength of the base material changes 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 the reinforcing fiber yarn changes, the strength or thickness of the base material also changes. Thereby, the strength or thickness of the base material can be changed according to the strength or thickness of each place required for the FRP product.

In the present 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. Therefore, a base material having a desired strength distribution can be easily knitted. It should be noted that local changes in the arrangement of the reinforcing fiber yarns are not excluded because holes for passing the pipes are provided.

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

The arrangement direction and the number of layers can be changed at the same time. For example, it is assumed that the reinforcing fiber yarns are arranged in two layers, the longitudinal direction and the short side direction (course direction in knitting). Then, the base material has high strength in the biaxial direction consisting of the arrangement direction of these two layers, and low strength in the diagonal direction in between. In the present invention, the direction of the reinforcing fiber threads in the longitudinal direction is changed in the longitudinal direction, and one layer in which the reinforcing fiber threads are arranged in the longitudinal direction is divided into a layer arranged in the longitudinal direction, a layer arranged in the diagonal direction, and the like. It can be changed from the middle of the material. Further, the layers arranged in the diagonal direction can be two layers, one from the lower right to the upper left and the other from 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 in the base material. Not limited to the layer in which the reinforcing fiber threads are arranged in the longitudinal direction, the layer arranged in the short side direction is changed to two layers in which the arrangement direction of the reinforcing fiber threads is diagonal and one layer in the short side direction, for a total of three layers. Can be made to. Further, the layer changed into a plurality of layers such as three layers can be returned to one layer or the like depending on the position in the longitudinal direction in the base material.

The thickness and number of layers of the reinforcing fiber yarn greatly change the strength of the base material. In order to change the thickness, the yarn supply port for supplying the reinforcing fiber yarn may be changed in the middle of knitting. The number of layers can be changed in the same manner, but the number of layers can also be changed by dividing one layer into multiple layers having different arrangement directions and combining multiple layers having different arrangement directions into one layer as described above. Can be done.

By changing the thickness of the reinforcing fiber yarn or changing the number of layers, the thickness can be changed according to the position of the base material. Further, even if the arrangement pitch of the reinforcing fiber yarns is changed, the thickness thereof can be changed according to the position of the base material. In addition to these, the thickness can be changed by stacking the base materials. However, if the thickness is changed during the knitting of the base material, the thickness can be changed from the beginning according to the desired thickness shape.

The use of the knitted fabric base material for FRP is arbitrary, but preferably the knitted fabric base material for FRP has a wing shape.
Warps are placed along the longitudinal direction of the wing shape, and inlay threads are placed along the direction perpendicular to the longitudinal direction.
The warp or inlay thread at the base end of the wing shape becomes a bias thread that crosses the warp diagonally at the tip end of the wing shape.
Warps, inlays, and bias yarns consist of reinforced fiber yarns.
The base end of the wing shape has at least a layer of warps and a layer of inlay yarns.
The wing-shaped tip is provided with a layer of warps, a layer of inlay yarns, and at least two layers of bias that cross the warps in opposite directions.

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

Preferably, in a cross section perpendicular to the longitudinal direction of the knitted fabric base material for FRP, the length of the layers at both ends in the thickness direction along the width direction of the base material is compared with the layer at the center in the thickness direction of the base material. Make it longer. In this way, the edges of the layer become inconspicuous along the width direction of the substrate, and the surface of the substrate becomes smooth. This is important, for example, in reducing the resistance of the wing.

Preferably, the number of layers of the reinforcing fiber yarn at the base end of the blade shape is larger than the number of layers of the reinforcing fiber yarn at the tip portion of the blade shape, and the base end portion of the blade shape is thicker than the tip portion. .. Generally, a wing is required to have a thick base end portion to be attached to a boss or the like and a thin tip portion, and a knitted fabric base material for FRP that satisfies this requirement can be obtained.

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

Preferably, one FRP knitted fabric base material has a blade shape in the thickness direction of the blade. In this case, it is not necessary to stack the knitted fabric base material for FRP, and the wing can be easily manufactured.

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

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

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

Preferably, the knitted fabric base material for FRP comprises 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 contained in the FRP product (for example, the reinforcing fiber per area). The number of yarns) should be higher than the density of the reinforcing fiber yarns in the area not included in the FRP product. By doing so, the necessary parts of the knitted fabric base material for FRP can be reinforced, and the reinforcing fiber yarn can be effectively used.

Horizontal sectional view which shows the structure of the knitted fabric base material for FRP of an Example. The figure which shows typically the knitting method of the knitted fabric base material for FRP of an Example. Cross-sectional view of a long knitted fabric base material for FRP consisting of a warp and two bias yarns. The figure which shows schematically showing changing a part of a warp yarn and an inlay yarn into a bias yarn in a knitted fabric base material for FRP. A diagram schematically showing the structure of a knitted fabric base material for FRP with few steps on the surface. The figure which shows typically the example of the knitted fabric base material for FRP which has few steps on the surface and has a desired cross-sectional shape. A diagram schematically showing a knitted fabric base material for FRP in which the thickness and strength are varied depending on the location by adjusting the density of the warp yarn and the range in which the bias yarn is arranged. The density and thickness of the warp yarns are varied depending on the location, and the bias yarns are centrally arranged in the center of the width direction to schematically make a knitted fabric base material for FRP with increased strength and density in the center part in the width direction. Figure shown The figure which shows the knitted fabric base material for FRP of a wing shape The figure which shows typically the knitted fabric base material for FRP for a helmet. The figure which shows typically the box-shaped knitted fabric base material for FRP.

The following are the optimum examples for carrying out the invention.

1 to 11 show an example of a knitted fabric base material for FRP. FIG. 1 shows the basic structure of the knitted fabric base material 2 for FRP, where 3 is a warp, 4 is an inlay yarn (weft), 5 and 6 are bias yarns, and bias yarns 5 and 6 have vertical and horizontal yarn directions. It is inclined from. The vertical direction of the base material 2 is the direction perpendicular to the drawing, the horizontal direction is the left-right direction of the figure, the bias thread 5 is inclined so that the right side of the figure is higher than the drawing, and the bias thread 6 is the left side of the figure. It is tilted so that it is above the drawing.

Reference numeral 8 is a knitting yarn, which is knitted by a knitting machine to form a stitch 10 and a crossover yarn 9. The crossover yarn 9 penetrates the knitted fabric base material 2 for FRP and connects the front and back sides of the base material 2, and a part of the crossover yarn 9 holds 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 (vertical direction), and the rows of stitches 10 have different directions from the inlay yarn 4 and the bias yarns 5 and 6. Then, the warp thread 3, the inlay thread 4, and the bias threads 5 and 6 are fixed by the stitch 10 and the crossover thread 9.

In the embodiment, the warp thread 3 is fixed by the crossover thread 9, but the bias thread 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. The number of layers of the warp thread 3, the inlay thread 4, the bias thread 5, and 6 arranged between the stitch 10 and the crossover thread 9 is arbitrary, and is 4 layers in FIG.

The warp threads 3, inlay threads 4, bias threads 5 and 6 are reinforced fiber threads, and the materials are, for example, carbon fiber threads, glass fiber threads, and aramid fiber threads. Carbon fiber yarn and glass fiber yarn, which are hard to bend and have high strength, are suitable for the warp yarn 3, and aramid fiber yarn, which is easy to bend, is suitable for the inlay yarn 4. The inlay yarn 4 is not limited to the aramid fiber yarn, but may be carbon fiber yarn, glass fiber, or the like. The bias yarns 5 and 6 may be any reinforcing fiber yarn. In the embodiment, unless otherwise specified, carbon fiber yarn is used for the warp 3 and the bias yarns 5 and 6, and aramid fiber yarn is used for the inlay yarn 4, and the bias yarn 5 is required to be folded back at the lateral end of the base material. For ， 6, use carbon fiber yarn thinner than warp yarn 3. The knitting yarn 8 is a yarn such as nylon or polyester that can be knitted to form a knitted fabric.

In each embodiment, a plurality of reinforcing fiber yarns of the same material and, for example, the same thickness are arranged in parallel in the same direction. Multiple reinforcing fiber yarns parallel in the same direction are regarded as one element, and this is called one axis or one layer. For example, the knitted fabric base material 2 for FRP in FIG. 1 has four axes, and the number of axes is two or more in each embodiment. That is, the four axes of the warp thread 3, the inlay thread 4, and the bias threads 5 and 6 are not indispensable, and may be, for example, two axes or five or more axes. In the Knitted fabric base material for FRP, the direction of the warp 3 (the same as the direction in which the stitch 10 is connected up and down) is called the vertical direction, and the direction of the inlay yarn 4 (the same as the direction in which the knitting yarn 8 extends) is called the horizontal direction. The vertical direction is the wale direction at the time of knitting, and the horizontal direction is the course direction at the time of knitting.

FIG. 2 shows a method of knitting the base material 2, and the knitting machine used is a flat knitting machine or a circular knitting machine, and is provided with, for example, a pair of front and rear needle beds 11 and 12. The knitting yarn 8 is supplied from the 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 for cutting 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. Therefore, the process of reducing the number of axes in the middle of knitting becomes easy. If these yarns are removed from the FRP knitted fabric base material in the middle of 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 stitch 10 is formed by the needles of the needle bed 11, and the carrier 14 is moved on the side opposite to the needle bed 11 when viewed from the base material 2. Then, the crossover thread 9 is arranged so as to penetrate the base material 2 on the front and back sides. The knitting yarn 8 integrally fixes the warp yarn 3, the inlay yarn 4, and the bias yarns 5 and 6 of the base material 2, 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 base material. 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 also folded back at a desired position.

FIG. 3 shows a three-axis FRP knitted fabric base material 22 composed of warp yarns 3, bias yarns 5, and 6, and has no inlay yarn 4. The base material 22 has a long shape without folding back of the inlay thread 4. Depending on the location, the number of axes, the arrangement pitch of the reinforcing fiber yarns on each axis, the thickness, material, etc. of the reinforcing fiber yarns are changed, and the strength distribution or thickness according to the location in the knitted fabric base material for FRP. It is used as a base material provided with.

The warp or inlay yarn can be changed to a bias yarn in the middle of knitting the knitted fabric base material for FRP, and conversely, the bias yarn can be changed to a warp or inlay yarn in the middle of knitting the knitted fabric base material for FRP. FIG. 4 shows an example in which a part of the warp is changed to a bias yarn in the middle of knitting, but it is also possible to change all the warp to a bias yarn. It is also possible to change only a part of the bias yarn to a warp. Such a knitted fabric base material 32 for FRP is shown in FIG. The reinforcing fiber threads 35 and 36 are inserted into the base material 32 as warps by fixing the carrier halfway, and inserted as a bias thread 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 then diagonally arranged in the course direction (horizontal direction) and the wale direction (longitudinal direction) from the middle and inserted as a bias yarn. Since the knitting is performed by a flat knitting machine, the inlay yarn 4, the bias yarns 5 and 6 are folded back at the folded 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 from the middle of knitting the knitted fabric base material for FRP. For these purposes, the reinforcing fiber yarn may be supplied from a movable carrier. When the carrier is fixed, the reinforcing fiber yarn becomes a warp. If the carrier is moved little by little, such as for one stitch every few courses, it becomes a bias yarn, and if it is moved at the same speed as the carriage of a flat knitting machine or a circular knitting machine, it becomes an inlay yarn.

FIG. 5 shows a knitted fabric base material 40 for FRP having few steps on the surface. The outer layer (outer axis) of the base material 40 has a longer lateral length, and the inner layer (inner axis) has a shorter lateral length. When the outermost layers 41 and 41 of 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 step is generated. In FIG. 5, the inner layer is arranged symmetrically with respect to the base material 40, but it may be asymmetrical according to the shape of the final FRP product. In FIG. 5, the outermost layer 41 is a layer of inlay yarn, but a warp yarn or a bias yarn layer may be used.

In the knitted fabric base material 42 for FRP of FIG. 6, the outermost layer is made the longest in the lateral direction so that the step is not conspicuous, as in FIG. 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, the final shape such as twisting can be imparted by setting it in a mold and injecting resin into the mold to cure 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 required location, and the mechanical parts such as wings have the desired density distribution. It is also required. For example, in a wing or the like, the arrangement pitch of the reinforcing fiber yarns perpendicular to the longitudinal direction is small at the base end and large at the tip end, so that the arrangement of the reinforcing fiber yarns is arranged along the longitudinal direction of the knitted fabric base material 52 for FRP. Change the pitch. Further, the number of reinforcing fiber threads passing through a cross section perpendicular to the longitudinal direction of a wing or the like is changed along the longitudinal direction so as to be large at the base end portion and small at the tip end portion. As a result, the mass of the tip of the wing can be made smaller than the mass of the base. In order to meet 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 highest in carbon fiber, and lower in glass fiber and aramid fiber than in carbon fiber.

In the FRP knitted fabric base material 52 of FIG. 7, the bias yarns 5 and 6 are arranged on the left side of the figure in a wider range than the right side, and the pitch of the warp yarns 3 is reduced on the left side of the figure. As a result, the left side is thick and strong because the bias yarn layer is not on the right side. Also, the left side has a layer of bias yarn, which makes it more resistant to twisting. The right side is thin and the strength is low.

In the knitted fabric base material 62 for FRP of FIG. 8, thin warp threads 63 are arranged at both ends in the lateral direction at a large pitch, and thick warp threads 3 are arranged at a small pitch at the center. Bias threads 5 and 6 are concentrated in the center of the horizontal direction in the figure, and are not placed at both ends in the horizontal direction. For these reasons, the Knitted fabric base material 62 for FRP has a thick central portion in the lateral direction and high strength, and both ends in the lateral direction are thin and low in strength.

FIG. 9 shows a knitted fabric base material 72 for FRP for wings, such as gas turbines, compressors, blower wings, ship or aircraft propellers, wind power blades, main wings of small aircraft, auxiliary wings, and the like. Gas turbines, compressors, blower blades, ship or aircraft propellers, wind blades, etc. are impeller or rotor blades. The wing shape means the shape of a wing of an aircraft or the like, and a blade of an impeller or a rotor. In the example at the top of the figure, the FRP knitted fabric base material 73,74 composed of four layers and the FRP knitted fabric base material having two or four layers from the tip end portion to the base end portion of the wing shape are used. Organize 75. In the area 76 on the left side, the base materials 73 and 74 are composed of, for example, two vertical and horizontal axes and two bias threads, for a total of four axes, and the rigidity against twisting is increased by increasing the number of axes. That is, when two axes of the bias yarn are added to the two axes of the vertical and horizontal directions, the rigidity to bend is increased, and thereby the rigidity to twist is also increased. In the region 77, which is the base of the wing and is housed in a boss or the like and is difficult to apply bending stress, the bias yarn is changed to a warp yarn or an inlay yarn and knitted into two axes. Further, the number of layers of the warp yarn or the number of layers of the inlay yarn is increased so that the region 77 can be easily fixed to the boss, and the thickness of the region 77 is increased. Therefore, in the region 77, carriers such as warp yarns and inlay yarns are added to increase the number of layers of warp yarns or inlay yarns.

The FRP knitted fabric base material can appropriately control the position where the reinforcing fiber yarn is inserted into the knitted fabric, and can also appropriately control the position where the insertion of the reinforcing fiber yarn is stopped. Therefore, the knitted fabric base material for FRP can be knitted into almost any shape in a plan view. In the case of a wing, the tip is arcuate and the side ends are curved. Then, the knitted fabric base materials 73 and 74 for FRP are knitted into 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 placed on top of the folded base material 75 to form a wing-shaped FRP knitted fabric base material 72. This is set in a mold and heated to disassemble the knitting yarn. The heating temperature may be changed according to the material of the knitting yarn used. In addition, the base material is impregnated with resin before being set in the mold, or the resin is injected in the mold to make an FRP product in the shape of a wing. The wing has a complicated cross-sectional shape, and the base material 72 is set in the mold, and the base material 72 is deformed along the mold to give a desired cross-sectional shape.

In the FRP base material 78 at the lower part of FIG. 9, the number of layers of the reinforcing fiber yarn is increased to more than four layers, or the reinforcing fiber yarn is made thicker than the FRP base material 72. Then, 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 stage of FIG. 9 in a side view. The FRP base material 78 is set in the mold in the same manner and processed in the same manner.

FIG. 10 shows the FRP knitted fabric base material 82 for a helmet, and the shape after molding with a mold is hemispherical. When the circular region 84 becomes a helmet and the flat base material 82 is made hemispherical, the spacing between the reinforcing fibers becomes large, the density becomes low, and the strength becomes insufficient. The area around the circular area 84 of the knitted fabric base material 82 for FRP is an area not included in the FRP product. Therefore, warp yarn 85 and inlay yarn 86 are added to the region 84. In the figure, ▲ indicates the position where the inlay thread is introduced, and Δ indicates the position where the inlay thread is not inserted into the base material. The carrier of the inlay yarn is movable, the carrier waiting on the outside of 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 of ▲. The carrier is moved out of the base material 82 at the position of Δ, and the inlay thread 86 is cut by a cutter or the like. The carrier of the inlay yarn 86 may be made to stand by in the base material 82 from the beginning, and the carrier may be retained in the base material 82 even after the inlay yarn 86 is cut. Further, the free inlay yarn may be generated 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 warp is used as the base material near the end of the region 84, for example, by a power roller and an air flow. Insert into 82. When the knitting of the region 84 is completed, the power roller and the air flow are stopped, and the insertion of the warp 85 is stopped. For example, a cutter cuts the end of the warp 85 and moves the carrier of the warp 85 to the outside of the substrate 82. In the case of the warp 85, the carrier may be made to stand by in the base material 82 from the beginning, and the carrier may be retained in the base material 82 even after the end is cut. Therefore, the carrier of the warp 85 may be a fixed carrier. Further, the free warp yarn may be generated without cutting the end portion of the warp yarn 85 yarn. As a result, in the knitted fabric base material for FRP, the density of the reinforcing fiber yarn is higher in the region contained in the FRP product than in the region not contained in the FRP product.

FIG. 11 shows a box-shaped knitted fabric base material 92 for FRP. 93 and 94 are bending 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 base material 92 has a box-like shape. It should be noted that the edge 95a, the edge 96a, etc. are connected by the turn-back knitting. In the turn-back knitting, for example, knitting is performed in the order from the bottom to the top of FIG. 11, the stitches of the edges 95a and 95b are held on the needle without being removed from the needle, and the knitting line 94 is knitted while reducing the knitting width. Next, a new stitch is formed on the stitches of the edges 95a and b to widen the stitch width. The warp and bias yarns passing through the edges 95a and b are left as they are until the edges 96b are knitted. Similarly, the edges 97a, b are connected to the edges 98a, b.

Inlay threads and warps are inserted on the entire surface of the base material 92, but the bent lines 93 and 94 are easily deformed by an external force. Therefore, reinforcing fibers are inserted into the region 100 around the bending line 93 and the region 101 around the bending line 94 to add warp yarns, inlay yarns, and the like to increase the strength as compared with other regions. The movement of the carrier for this purpose, the cutting of the excess inlay yarn and the warp, and the like are the same as those in the embodiment of FIG.

2,22,32,40,42,52,62 Knitted fabric base material for FRP
3,63 warp
4,34 Inlay thread
5,6,35,36 Bias thread
8 knitting yarn
9 Crossover thread
10th stitch
11,12 Needle bed
14 Career
38 Folded part
41 outermost layer
43 layers
Knitted fabric base material for 72-75 FRP
76,77 areas
78,82 Knitted fabric base material for FRP
84 areas
85 warp
86 inlay thread
92 Knitted fabric base material for FRP
93,94 Bending line
95a-98b edge
100,101 area

Claims (11)

In a knitted fabric base material for FRP in which multiple layers consisting of parallel reinforcing fiber yarns are fixed by knitting yarns.
The arrangement pitch, arrangement direction, thickness, or number of layers of the reinforcing fiber yarns of the reinforcing fiber yarns change according to the position in the base material, so that the strength of the base material changes according to the position. ,
Warps are arranged along the longitudinal direction of the knitted fabric base material for FRP, and inlay yarns are arranged along the direction perpendicular to the longitudinal direction.
The warp or inlay yarn at the base end in the longitudinal direction becomes a bias yarn that diagonally crosses the warp at the tip in the longitudinal direction .
Warps, inlays, and bias yarns consist of reinforced fiber yarns.
At the base end in the longitudinal direction, the knitted fabric base material for FRP includes at least a layer of warp yarn and a layer of inlay yarn.
Moreover, the knitted fabric base material for FRP at the tip portion in the longitudinal direction is characterized by having a layer of warp yarn, a layer of inlay yarn, and at least two layers of bias in which the direction of crossing with the warp yarn is opposite. Knitted fabric base material for FRP. The knitted fabric base material for FRP has a wing shape,
The longitudinal direction is the longitudinal direction of the wing shape.
The knitted fabric base material for FRP according to claim 1, wherein the base end portion in the longitudinal direction is a base end portion having a wing shape, and the tip end portion in the longitudinal direction is a tip end portion having a wing shape. The number of layers of the reinforcing fiber yarn at the proximal end portion in the longitudinal direction is larger than the number of layers of the reinforcing fiber yarn at the distal end portion in the longitudinal direction, and FRP is made at the proximal end portion in the longitudinal direction. The FRP knitted fabric base material according to claim 1 , wherein the knitted fabric base material is thicker than the tip portion. The FRP knitted fabric base material according to claim 2 , wherein the FRP knitted fabric base material has a wing shape also in the thickness direction of the wing. The knitted fabric base material for FRP according to claim 2 , wherein the knitted fabric base material for FRP is configured to have a wing shape when laminated in the thickness direction of a plurality of blades. In a knitted fabric base material for FRP in which multiple layers consisting of parallel reinforcing fiber yarns are fixed by knitting yarns.
The arrangement pitch, arrangement direction, thickness, or number of layers of the reinforcing fiber yarns of the reinforcing fiber yarns change according to the position in the base material, so that the strength of the base material changes according to the position. ,
In the cross section perpendicular to the longitudinal direction of the knitted fabric base material for FRP, the layers at both ends in the thickness direction have a longer length in the width direction than the layer at the center in the thickness direction of the base material. A knitted fabric base material for FRP. In a knitted fabric base material for FRP in which multiple layers consisting of parallel reinforcing fiber yarns are fixed by knitting yarns.
The arrangement pitch, arrangement direction, thickness, or number of layers of the reinforcing fiber yarns of the reinforcing fiber yarns change according to the position in the base material, so that the strength of the base material changes according to the position. ,
A knitted fabric base material for FRP, characterized in that the arrangement pitch of the reinforcing fiber yarns perpendicular to the longitudinal direction of the knitted fabric base material for FRP changes along the longitudinal direction. Any of claims 1, 2, 3, 6 and 7 , characterized in that the number of reinforcing fiber yarns passing through a cross section perpendicular to the longitudinal direction of the knitted fabric substrate for FRP changes along the longitudinal direction. Knitted fabric base material for FRP. In a knitted fabric base material for FRP in which multiple layers consisting of parallel reinforcing fiber yarns are fixed by knitting yarns.
The arrangement pitch, arrangement direction, thickness, or number of layers of the reinforcing fiber yarns of the reinforcing fiber yarns change according to the position in the base material, so that the strength of the base material changes according to the position. ,
The knitted fabric base material for FRP includes an area included in the FRP product and an area not included in the FRP product.
A knitted fabric base material for FRP, characterized in that the density of the reinforced fiber yarn in the region included in the FRP product is higher than the density of the reinforced fiber yarn in the region not included in the FRP product. The knitted fabric base material for FRP according to any one of claims 1 to 9 , wherein the thickness of the reinforcing fiber yarn or the number of layers of the reinforcing fiber yarn changes depending on the position in the base material. The knitted fabric base material for FRP according to any one of claims 1 to 10, wherein the thickness changes depending on the position in the base material.

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