JP2014213521A - Three-dimensional fiber-reinforced composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve reduction of a resin accumulation amount in a root part of a sewing thread folded in a loop form and improvement of the fiber volume content at the same time by using a fiber structure formed by binding an at least two-axis oriented laminate fiber layer with a sewing thread and a fastening thread.SOLUTION: A three-dimensional fiber structure 10 serving as a reinforcing base material for three-dimensional fiber-reinforced composite materials is formed by binding two-axis oriented laminate fiber layers 12 composed of in-plane thread layers 11 laminated by means of a sewing thread 13 and a fastening thread 14. The sewing thread 13 includes a folding insertion part 13a which is engaged with the fastening thread arranged on one outermost layer of the laminate fiber layers 12 so as to be folded in a loop form and inserted into the laminate fiber layers and an opposite fastening thread-side arrangement part 13b which is arranged outside the surface of the laminate fiber layers opposite to the surface where the fastening thread are arranged. In the root part 16 of the folded insertion part 13a, an inlet part 13c in the direction toward the fastening thread and an outlet part 13d in the direction of being engaged with the fastening thread and folded are bent in the same direction.

Description

  The present invention relates to a three-dimensional fiber reinforced composite material, and more specifically, a fiber structure formed by binding at least biaxially oriented laminated fiber layers in which in-plane yarn layers are laminated with sewing threads and fastening threads. The present invention relates to a three-dimensional fiber reinforced composite material.

  Fiber reinforced composites are widely used as lightweight structural materials. There is a three-dimensional fabric (three-dimensional fiber structure) as a reinforcing base material for composite materials. A composite material using this three-dimensional woven fabric as a reinforcing base and a resin as a matrix is used as a structural member for aircraft, automobiles, ships, or general industrial equipment. Three-dimensional woven composite materials (three-dimensional fiber reinforced composite materials) are different from fiber reinforced composite materials formed by impregnating and curing resin in reinforced fabrics such as woven fabrics and non-woven fabrics. A three-dimensional woven fabric having thickness direction yarns (out-of-plane direction yarns) arranged in a direction intersecting with the (inner oriented yarn) is used as the reinforcing base material. Therefore, compared to a fiber reinforced composite material that does not have an out-of-plane direction yarn, it has a high out-of-plane direction strength, but there is a quality problem that cracks are likely to occur around the thickness direction yarn (out-of-plane direction yarn). is there.

  In order to cope with this problem, a three-dimensional fiber reinforced resin composite material is proposed in which a resin is impregnated and cured in a three-dimensional fabric in which a plurality of layers of laminated in-plane direction yarns are stitched together with sewing threads made of organic fibers. Yes. (See Patent Document 1). As shown in FIG. 7, the three-dimensional fiber reinforced resin composite material of Patent Document 1 is orthogonal to the reference plane of the in-plane direction yarn 53 composed of a plurality of warps 51 and a plurality of wefts 52 and the in-plane direction yarn 53. A plate-like three-dimensional woven fabric 56 formed of a plurality of out-of-plane direction threads (sewing threads) 54 and ear threads (fastening threads) 55 for fixing the out-of-plane direction threads 54 is impregnated with resin, and heated and pressurized. And then cured. As the out-of-plane direction yarn 54, one having 1000 denier or less is used.

JP 2007-152672 A

  The three-dimensional fiber reinforced resin composite material of Patent Document 1 uses an organic fiber for the out-of-plane direction yarn 54, so that it has a thermal property closer to that of the matrix resin than inorganic fibers, and reduces internal strain that causes cracks. To do. Further, by using a thin thread having a denier of 1000 denier or less, a treatment indicated by the thicknesses of the loops of the out-of-plane direction thread 54 and the thickness of the out-of-plane direction thread 54 and the ear thread 55 is shown by arrows A and B in FIG. This is effective as a measure for reducing the resin pool in the gap between the tool and the in-plane direction thread 53.

  However, in these measures, as a measure for reducing the resin pool in the portion indicated by the arrow C in FIG. 7, that is, the root portion of the out-of-plane direction yarn 54, there is a contradiction that the tension of the out-of-plane direction yarn 54 cannot be increased. It is not valid. Further, if the tension of the out-of-plane direction thread 54 cannot be increased, there is a problem that the fiber volume content (about Vf 55%) of a general structural CFRP (carbon fiber reinforced resin) material cannot be realized.

  Further, the out-of-plane direction thread 54 extends in a direction orthogonal to each fiber layer of the laminated fiber layer, engages with the ear thread 55, and is looped back and arranged, and the ear thread 55 of the laminated fiber layer. And a portion arranged along the surface layer on the opposite side. Therefore, when the out-of-plane direction thread 54 is tightened in the manufacturing process of the flat plate-like three-dimensional woven fabric 56, it is engaged with the ear thread 55 of the out-of-plane direction thread 54 and folded at the root portion of the looped portion. The portion arranged along the surface layer opposite to the ear yarn 55 side of the laminated fiber layer acts so as to widen the spacing between the out-of-plane direction yarns 54. As a result, the flat plate-like three-dimensional woven fabric 56 is in a state in which the distance between the root portions of the out-of-plane direction yarns 54 is widened, and a fiber-reinforced composite material (fiber-reinforced resin) is formed using the flat plate-like three-dimensional woven fabric 56 as a reinforcing base material. When formed, the amount of the resin pool at the base portion of the out-of-plane direction thread 54 increases, and cracks are likely to occur from the resin pool portion.

  The present invention has been made in view of the above problems, and its purpose is to use a fiber structure formed by binding a laminated fiber layer that is at least biaxially oriented with a sewing thread and a fastening thread as a reinforcing base material. It is an object of the present invention to provide a three-dimensional fiber reinforced composite material that can be used to achieve both a reduction in the amount of resin pool at the base of a sewing thread that is folded back into a loop and an improvement in the fiber volume content.

  A three-dimensional fiber reinforced composite material that solves the above-described problem is a fiber structure formed by binding a laminated fiber layer having at least biaxial orientation in which in-plane yarn layers are laminated with a sewing thread and a fastening thread as a reinforcing base material. It is a three-dimensional fiber reinforced composite. And as for the said fiber structure, the said thread is arranged on the outermost layer of any one of the said laminated fiber layers. The sewing thread is engaged with the fastening thread, folded back in a loop shape and inserted into the laminated fiber layer, and the outer side of the surface of the laminated fiber layer opposite to the side where the fastening thread is arranged. And at the base part of the folded back insertion part, an entry side part in the direction toward the fastening thread and an output in the direction of folding back by engaging with the fastening thread. The side part is bent in the same direction.

  According to this configuration, when tightening the sewing thread that binds the laminated fiber layer in cooperation with the fastening thread in the manufacturing process of the fiber structure that becomes the reinforcing base, the surface layer on the opposite side of the fastening thread side of the laminated fiber layer The anti-fastening thread side arrangement part of the sewing thread arranged along the line does not act so as to widen the interval of the sewing thread at the root part of the return insertion part of the sewing thread. Therefore, in a three-dimensional fiber reinforced composite material using a fiber structure formed by binding a laminated fiber layer that is at least biaxially oriented with a sewing thread and a fastening thread as a reinforcing base material, It is possible to achieve both a reduction in the amount of resin pool and an improvement in the fiber volume content.

  The sewing thread is inserted in a folded shape at a position apart from one pitch from one end in the width direction of the laminated fiber layer, and then inserted in a folded shape at a position returning by one pitch. It is preferable that the insertion is repeated so as to repeat the previous position and the position returned by one pitch from the position three pitches ahead. According to this configuration, when the fiber structure is manufactured, the sewing thread is formed in the laminated fiber layer so that the portions inserted into the laminated fiber layer are engaged with the fastening thread of the sewing thread, folded back into a loop shape, and inserted into the laminated fiber layer. The insertion work is easier than other insertion methods.

  According to the present invention, in a three-dimensional fiber reinforced composite material using a fiber structure formed by binding laminated fiber layers that are at least biaxially oriented with a sewing thread and a fastening thread as a reinforcing base material, a sewing thread that is folded back into a loop shape. It is possible to achieve both a reduction in the amount of resin pool at the base of the fiber and an improvement in the fiber volume content.

The schematic perspective view of the three-dimensional fiber structure of one Embodiment. The schematic cross section of a three-dimensional fiber structure. The schematic diagram which shows the relationship between a sewing thread and a fastening thread. (A) is a schematic cross section of the three-dimensional woven fiber reinforced composite material using the three-dimensional fiber structure of the embodiment, and (b) is a partially enlarged view of (a). (A) is a schematic cross section of a three-dimensional woven fiber reinforced composite material using a conventional three-dimensional fiber structure, and (b) is a partially enlarged view of (a). (A), (b) is a schematic diagram which shows the relationship between the sewing thread | yarn of another embodiment, and a fastening thread, respectively. The schematic cross section of a prior art.

(First embodiment)
Hereinafter, the first embodiment will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the three-dimensional fiber structure 10 as a fiber structure used as a reinforcing base material of a three-dimensional fiber-reinforced composite material has at least biaxial orientation in which in-plane thread layers 11 are laminated. The laminated fiber layer 12 is formed by binding the sewing thread 13 and the fastening thread 14 together. In the three-dimensional fiber structure 10, the fastening thread 14 is arranged on one of the outermost layers of the laminated fiber layer 12.

  The sewing thread 13 engages with the fastening thread 14 and is folded back into a loop shape to be inserted into the laminated fiber layer 12, and on the surface opposite to the side on which the fastening thread 14 of the laminated fiber layer 12 is arranged. And an anti-fastening thread side array portion 13b arranged on the outside. The sewing thread 13 engages with the fastening thread 14 and the entry side 13c in the direction toward the fastening thread 14 at the base part 16 of the folding insertion part 13a that engages with the fastening thread 14 and folds in a loop. The direction exit side 13d is bent in the same direction. The arrangement surface Pz of the sewing thread 13 is orthogonal to the arrangement direction of the fastening thread 14. In this embodiment, the arrangement surface Pz is parallel to the in-plane thread having an orientation angle of 0 degrees.

  As shown in FIG. 3, in this embodiment, the sewing thread 13 is basically inserted into the laminated fiber layer 12 in a folded shape at an interval of 3 pitches, and then folded back at a position returning by 1 pitch. It consists of repeated insertions. However, the first part of the sewing thread 13 inserted into the laminated fiber layer 12 is inserted into the laminated fiber layer 12 in a folded shape at a position away from the end by one pitch, and then inserted in a folded shape at a position returning by one pitch. The In other words, the sewing thread 13 is arranged so that the folded insertion portions 13 a that are engaged with the fastening thread 14 and folded back into a loop shape and inserted into the laminated fiber layer 12 exist at a constant pitch P. One pitch is about 3 mm, for example.

  As shown in FIG. 2, in this embodiment, the laminated fiber layer 12 includes an in-plane thread layer 11a made of continuous fibers having an orientation angle of 0 degrees, an in-plane thread layer 11b made of continuous fibers having an orientation angle of 90 degrees, A predetermined number of in-plane thread layers 11c made of continuous fibers with an orientation angle of 45 degrees and in-plane thread layers 11d made of continuous fibers with an orientation angle of -45 degrees are laminated to form a quasi-isotropic property. The in-plane yarn layer 11c made of continuous fibers with an orientation angle of 45 degrees or the in-plane yarn layers 11d made of continuous fibers with an orientation angle of -45 degrees are arranged on both surfaces of the laminated fiber layer 12 in the thickness direction. The continuous fibers become in-plane yarns arranged in a plane orthogonal to the thickness direction of the three-dimensional fiber structure 10 (vertical direction in FIG. 2).

  For example, carbon fiber is used as the in-plane thread, the sewing thread 13 and the fastening thread 14. Carbon fiber has a number of filaments of about several hundred to several tens of thousands, and the number of fiber bundles suitable for the required performance is selected. As the sewing thread 13 and the fastening thread 14, fiber bundles having basically the same thickness are used. Further, the sewing thread 13 and the fastening thread 14 may have the same thickness as the in-plane thread constituting the in-plane thread layer 11, but are preferably thinner than the in-plane thread.

  Next, an example of a manufacturing method of the three-dimensional fiber structure 10 configured as described above will be described. The three-dimensional fiber structure 10 has a plurality of holes having holes at the tip, as in a known method for the laminated fiber layer 12, for example, a thickness direction thread (sewing thread) insertion method disclosed in JP-A-8-218249. The sewing thread 13 is inserted using a book insertion needle. That is, in the thickness direction of the laminated fiber layer 12, after inserting a plurality of insertion needles, each having a sewing thread 13 hooked into a hole provided at the tip, until each insertion needle hole penetrates the laminated fiber layer 12, The insertion needle is retracted slightly, and the retaining thread 14 is inserted into the looped portion of the sewing thread 13. In this state, the insertion needle is pulled back, and the tension thread 14 is tightened by the sewing thread 13 in a state where tension is applied to the retaining thread 14, and the in-plane thread layers 11 are coupled. However, unlike conventional insertion methods, the insertion needles are not sequentially inserted into the laminated fiber layer 12 at a constant pitch.

  More specifically, the sewing thread 13 is inserted into the folded insertion portion 13a at the position indicated by the second I from the left in FIG. It is inserted at the position indicated by II on the leftmost side after returning to the pitch. Next, it is inserted at a position indicated by III, which is three pitches after the position indicated by II, and then inserted by a position indicated by IV which is one pitch back from that position. Thereafter, it is inserted into the laminated fiber layer 12 so as to repeat “3 pitches ahead” and “1 pitch return”. Note that the position at which the sewing thread 13 is first inserted into the laminated fiber layer 12 is not located at a pitch of 3 pitches from the end of the laminated fiber layer 12, but at approximately 1 pitch interval from an end where there is room to return by 1 pitch. It will be the position where you put it.

  Then, the sewing thread 13 engages with the fastening thread 14 and engages with the fastening thread 14 at the base part 16 of the folding insertion part 13a that engages with the fastening thread 14 and folds in a loop. It will be in the state inserted in the lamination | stacking fiber layer 12 in the state bent to the exit side part 13d of the coming direction in the same direction.

  Therefore, when the insertion needle is pulled back and the fastening thread 14 is tightened by the sewing thread 13 in a state where tension is applied to the fastening thread 14, it engages with the fastening thread 14 of the sewing thread 13 and is folded back into a loop to be inserted into the laminated fiber layer 12. A tension is applied to the root portion 16 of the folded-back insertion portion 13a in the direction indicated by the arrow F in FIG. That is, no tension acts on the entry side portion 13c and the exit side portion 13d of the root portion 16 of the folded insertion portion 13a inserted in a folded shape in the direction of widening the interval. Therefore, when the tension of the sewing thread 13 and the fastening thread 14 is increased and a large compressive force is applied to the laminated fiber layer 12, the fiber volume density of the three-dimensional fiber structure 10 is increased without increasing the opening of the root portion 16. Can do. As a result, in the three-dimensional fiber structure 10, the volume occupied by a portion that becomes a resin pool when the three-dimensional fiber structure 10 is impregnated with resin at a location corresponding to the root portion 16 of the folded insertion portion 13 a of the sewing thread 13. Becomes smaller.

  On the other hand, in the conventional method of inserting a sewing thread in which insertion needles are sequentially inserted into the laminated fiber layer 12 at a constant pitch, when the tension of the sewing thread 13 and the fastening thread 14 is increased to apply a large compressive force to the laminated fiber layer 12. The tension acts on the entry side portion 13c and the exit side portion 13d of the root portion 16 of the folded back insertion portion 13a of the sewing thread 13 in the direction of widening the interval. As a result, in the three-dimensional fiber structure 10, the volume occupied by a portion that becomes a resin pool when the three-dimensional fiber structure 10 is impregnated with resin at a location corresponding to the root portion 16 of the folded insertion portion 13 a of the sewing thread 13. Becomes larger.

  The three-dimensional fiber structure 10 is used as a reinforced base material of a three-dimensional fiber reinforced resin as a three-dimensional fiber reinforced composite material. The three-dimensional fiber reinforced resin is configured by impregnating and curing a three-dimensional fiber structure 10 with, for example, a thermosetting resin such as an epoxy resin. As shown in FIGS. 4A and 4B, in the three-dimensional fiber reinforced resin of the embodiment, the sewing thread 13 is engaged with the fastening thread 14 and folded at the root portion 16 of the folded insertion portion 13a. The entering side portion 13c in the direction toward the clasp 14 and the exit side portion 13d in the direction of engaging and folding back with the clasp 14 are inserted into the laminated fiber layer 12 in a state of bending in the same direction. . Since the resin is impregnated and cured in a state in which the opening of the entry side portion 13c and the exit side portion 13d is prevented, the resin reservoir 17 is formed at a location corresponding to the root portion 16 of the folded insertion portion 13a of the sewing thread 13. The volume occupied by the portion is reduced. Therefore, the occurrence of cracks from the resin reservoir 17 is suppressed.

  On the other hand, as shown in FIGS. 5 (a) and 5 (b), in the prior art, the sewing thread 13 is engaged with the fastening thread 14 and folded into a loop shape to be turned into the fastening thread 14 at the root portion 16 of the folded insertion portion 13a. The entering side portion 13c in the direction toward and the exit side portion 13d in the direction of being engaged with the clasp 14 and bent back are bent in the opposite direction and are inserted into the laminated fiber layer 12. Therefore, the opening of the entry side portion 13c and the exit side portion 13d is increased, and the three-dimensional fiber reinforced resin using the three-dimensional fiber structure as a reinforcing base corresponds to the root portion 16 of the folded insertion portion 13a of the sewing thread 13. The resin reservoir 17 at the place where the resin is accumulated becomes large, and cracks are easily generated from the resin reservoir 17 portion.

According to this embodiment, the following effects can be obtained.
(1) A three-dimensional fiber reinforced composite material is a reinforcing structure of a fiber structure formed by binding a laminated fiber layer 12 having at least biaxial orientation in which in-plane yarn layers 11 are laminated with a sewing thread 13 and a fastening thread 14. It is a three-dimensional fiber reinforced composite material. In the fiber structure (three-dimensional fiber structure 10), the fastening thread 14 is arranged on one of the outermost layers of the laminated fiber layer 12. The sewing thread 13 engages with the fastening thread 14 and is folded back into a loop shape to be inserted into the laminated fiber layer 12, and on the surface opposite to the side on which the fastening thread 14 of the laminated fiber layer 12 is arranged. And an anti-fastening thread side array portion 13b arranged on the outside. In the root portion 16 of the folded back insertion portion 13a, the entry side portion 13c in the direction toward the retaining thread 14 and the exit side portion 13d in the direction of engaging with the retaining thread 14 and folded back are bent in the same direction. Therefore, a three-dimensional fiber reinforced composite material using a fiber structure (three-dimensional fiber structure 10) formed by binding the laminated fiber layer 12 having at least biaxial orientation with the sewing thread 13 and the fastening thread 14 as a reinforcing substrate. Thus, it is possible to achieve both a reduction in the amount of resin pool at the base portion 16 of the sewing thread 13 that is folded back into a loop and an improvement in the fiber volume content.

  (2) The sewing thread 13 is inserted in a folded shape at a position away from one pitch from one end in the width direction of the laminated fiber layer 12, and then inserted in a folded shape at a position returning by one pitch. Are inserted so as to repeat a position three pitches ahead and a position one pitch back from the position three pitches ahead. Therefore, when the fiber structure (three-dimensional fiber structure 10) is manufactured, the folded insertion portions 13a engaged with the fastening threads 14 of the sewing thread 13 and folded back into a loop shape and inserted into the laminated fiber layer 12 are formed at a constant pitch. The operation of inserting the sewing thread 13 into the laminated fiber layer 12 so as to exist is simpler than other insertion methods.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The sewing thread 13 is not limited to being configured by repeatedly inserting the sewing thread 13 at a position returning by 1 pitch after being inserted in a folded shape at intervals of 3 pitches. For example, as shown in FIG. 6 (a), the sewing thread 13 engages with the retaining thread 14 arranged along the outermost in-plane thread layer 11c of the laminated fiber layer 12 and is folded back into a loop shape to form the laminated fiber. The insertion position of the folded insertion portion 13a to be inserted into the layer 12 is sequentially inserted so as to be changed from the outside to the inside in the width direction of the laminated fiber layer 12 (left and right direction in FIG. 6A). May be good.

  As shown in FIG. 6 (b), the sewing thread 13 engages with the fastening thread 14 arranged along the outermost in-plane thread layer 11c of the laminated fiber layer 12, and is folded back into a loop shape to form the laminated fiber layer. The insertion position of the folded back insertion portion 13a inserted into 12 is sequentially inserted so as to be changed from the inner side to the outer side in the width direction of the laminated fiber layer 12 (left and right direction in FIG. 6B). It may be a thing.

  The sewing thread 13 is engaged with the fastening thread 14, folded back in a loop and inserted into the laminated fiber layer 12, at the root part 16 of the folded insertion part 13 a, and an entry side part 13 c in the direction toward the fastening thread 14, The exit side portion 13d in the direction of being engaged with the yarn 14 and being turned back may be bent in the same direction. Therefore, the sewing thread 13 may be inserted at different intervals, instead of the fixed insertion pitch 13a.

  ○ The fiber bundle constituting the in-plane thread layer 11 is not limited to carbon fiber, for example, inorganic fiber such as glass fiber or ceramic fiber, or aramid fiber, poly-p-phenylenebenzobisoxazole fiber, polyarylate fiber, ultra It may be a high-strength organic fiber such as a high molecular weight polyethylene fiber, and is appropriately selected according to the required performance. For example, when the required performance of rigidity and strength for the fiber reinforced composite material is high, carbon fiber is preferable. If an inexpensive glass fiber is used for the fiber bundle, the cost becomes low.

  ○ The lamination order of the in-plane yarn layers 11a to 11d that constitute the laminated fiber layer 12 in a pseudo-isotropic and in-plane four-axis orientation is such that the outer layer is the in-plane yarn layer 11c (+45 degree layer) or the in-plane yarn layer 11d ( -45 degree layer).

  The laminated fiber layer 12 only needs to be at least biaxially oriented, and is not limited to in-plane tetraaxial orientation with pseudo-isotropic properties. For example, when the in-plane triaxial laminated fiber layer 12 is composed of yarns having an orientation angle of 0 degrees, 60 degrees, and −60 degrees, or the in-plane 4-axis laminated fiber layer 12 is formed, the orientation angle is The orientation angle of other in-plane aligned yarns of 0 degree and 90 degrees may be an orientation angle other than ± 45 °. The laminated fiber layer 12 may be in-plane biaxial orientation with orientation angles of 0 degrees and 90 degrees.

  The matrix resin constituting the three-dimensional fiber reinforced composite material is not limited to a thermosetting resin, and for example, a thermoplastic resin such as polyamide, polybutylene terephthalate, polycarbonate, polyoxymethylene, or polyphenylene ether may be used.

The following technical idea (invention) can be understood from the embodiment.
(1) A fiber structure in which a laminated fiber layer having at least biaxial orientation in which in-plane yarn layers are laminated is bound with a sewing thread and a fastening thread, wherein the fastening thread is one of the laminated fiber layers The sewing thread is arranged on one outermost layer, the sewing thread is engaged with the fastening thread, folded back in a loop shape and inserted into the laminated fiber layer, and the fastening thread of the laminated fiber layer is arranged. An anti-fastening thread side arraying portion arranged on the outer side of the opposite side surface, and an entry side portion in a direction toward the fastening yarn at a root portion of the folded insertion portion, and an engagement with the fastening yarn The exit side in the direction of folding back is bent in the same direction.

  Pz: arrangement surface, 10: three-dimensional fiber structure as a fiber structure, 11, 11a, 11b, 11c, 11d ... in-plane thread layer, 12 ... laminated fiber layer, 13 ... sewing thread, 13a ... folded insertion part, 13b ... anti-fastener side arrangement part, 13c ... entry side part, 13d ... exit side part, 14 ... fastener thread, 16 ... root part.

Claims (2)

A three-dimensional fiber reinforced composite material comprising a fiber structure formed by binding a laminated fiber layer having at least biaxial orientation in which in-plane yarn layers are laminated together with a sewing thread and a fastening thread,
In the fiber structure, the fastening thread is arranged on the outermost layer of any one of the laminated fiber layers,
The sewing thread is engaged with the fastening thread, folded back in a loop shape and inserted into the laminated fiber layer, and the outer side of the surface of the laminated fiber layer opposite to the side where the fastening thread is arranged. And at the base part of the folded back insertion part, an entry side part in the direction toward the fastening thread and an output in the direction of folding back by engaging with the fastening thread. A three-dimensional fiber reinforced composite material characterized in that the side portion is bent in the same direction.   The sewing thread is inserted in a folded shape at a position apart from one pitch from one end in the width direction of the laminated fiber layer, and then inserted in a folded shape at a position returning by one pitch. The three-dimensional fiber-reinforced composite material according to claim 1, wherein the three-dimensional fiber reinforced composite material is inserted so as to repeat a previous position and a position returned by one pitch from the three pitch ahead position.