JP4775090B2 - Manufacturing method of fiber reinforced composite material - Google Patents

Description

  The present invention relates to a method for manufacturing a fiber reinforced composite material, and more particularly to a method for manufacturing a fiber reinforced composite material having a bent portion.

  Fiber reinforced composite materials (hereinafter sometimes simply referred to as composite materials) are widely used as lightweight structural materials. As a reinforcing material for composite materials, there is a three-dimensional fiber structure such as a three-dimensional fabric. In order to be able to use the three-dimensional fiber structure as a reinforcing material for a composite material in a wide range of applications, a three-dimensional fiber structure having a bent portion instead of a simple flat plate shape is required.

A method of using a frame has been proposed as a method for manufacturing a three-dimensional fiber structure having a bent portion (see, for example, Patent Document 1). In this method, a frame body is used in which a plurality of plate-like portions are formed in a shape corresponding to the shape of a three-dimensional fiber structure having a shape that is continuous in a bent state at a connection portion, and restriction members are arranged at a predetermined pitch. . Then, after forming a laminated yarn group by laminating yarn layers in which yarns are arranged in a folded manner between the regulating members on the frame, the thickness direction yarn is inserted in a state where the laminated yarn group is held on the frame.
JP-A-9-137336

  However, in the manufacturing method of Patent Document 1, it is necessary to prepare a frame corresponding to the shape of the three-dimensional fiber structure each time, and the thickness direction yarn is inserted into the laminated yarn group arranged on the frame in a bent state. The number of work steps to be performed increases and the apparatus becomes complicated. Moreover, in the method of arranging continuous fibers in a state of engaging with the regulating member using the frame body provided with the regulating member as in the manufacturing method of Patent Document 1, it has bent portions bent in different directions. A three-dimensional fiber structure cannot be produced.

  Therefore, after the laminated fiber layer formed by laminating the fiber layers made of continuous fibers forms a three-dimensional fiber structure bonded with a thread in the thickness direction, the three-dimensional fiber structure is bent and finally formed. In some cases, a three-dimensional fiber structure having a bent portion is formed.

  For example, as shown in FIG. 8, when manufacturing a three-dimensional fiber structure 61 having a substantially hat-shaped cross section, a laminated fiber layer 62 having a biaxial orientation formed by laminating fiber layers made of continuous fibers is thickened. It is conceivable to form by bending a flat plate-like three-dimensional fiber structure joined by the vertical thread 63. However, since the continuous fibers used in the three-dimensional fiber structure are generally very small in elongation, the continuous fibers arranged on the outer side in the bent portion cannot be extended, resulting in wrinkles 64 and distortion on the inner side. A three-dimensional fiber structure 61 is obtained. When the composite material (FRP) in which the three-dimensional fiber structure 61 is used as a reinforcing material and a resin is used as a matrix (FRP) is formed, the wrinkles 64 and distortion cause deterioration of physical properties (for example, strength reduction) and decrease appearance quality. .

  The present invention has been made in view of the above-described conventional problems, and the object thereof is to form a flat primary structure in which laminated fiber layers are bonded with a thickness direction thread by bending. Another object of the present invention is to provide a method for producing a fiber reinforced composite material including a bending step capable of producing a three-dimensional fiber structure in a state where generation of wrinkles and distortions in a bent portion is suppressed.

In order to achieve the above object, according to the first aspect of the present invention, there is provided a laminated fiber layer having at least biaxial orientation in which fiber layers made of continuous fibers are laminated, wherein bending parts having different bending directions are arranged with a flat part in between. A three-dimensional fiber structure that is formed in a three-dimensional plate shape having adjacent portions in an adjacent state and in which thickness direction yarns are arranged in a state of intersecting with each fiber layer of the laminated fiber layer It is the manufacturing method of the fiber reinforced composite material used as the reinforcing material. Then, a fiber layer formed by arranging continuous fibers between the regulating members so as to be engaged with the regulating member and turned back on a jig in which the regulating members are arranged at a predetermined pitch is laminated at least biaxially. A continuous fiber arraying step for forming a laminated fiber layer, and a thickness direction yarn insertion for forming a flat primary structure by inserting a thickness direction thread into the laminated fiber layer so as to penetrate the laminated fiber layer Process. Further, a bending step of forming a bent portion at a predetermined position of the flat primary structure into which the thickness direction thread is inserted, and the primary structure after bending is performed in the bending step in the mold. And a resin impregnation and curing step for impregnating and curing the resin. In the bending step, a portion of the primary structure is held by at least two holding members and tension is applied to the primary structure while pressing against the primary structure at an intermediate portion of the holding member. member by relatively moving the holding member and the pressing member so by adding pressing force exerts a bending force to the primary structure through the holding member and the sandwiched pressing member was the primary structure relative movement Bending parts having different bending directions are formed at both ends of the body.

  Here, the “three-dimensional plate shape” means that a flat plate is bent as a whole, and a three-dimensional shape is formed. The “continuous fiber” is not limited to a single fiber (monofilament) but includes a fiber bundle in which a plurality of single fibers are bundled. The “yarn” does not mean only a twisted yarn but also includes a fiber bundle (so-called roving) in which a large number of fibers are bundled and are not substantially twisted. The “holding member” means a member that is held in a state in which a portion in contact with the primary structure does not move relative to the primary structure when bending is performed. Hereinafter, the same meaning is used in this specification.

In this invention, the thread in the thickness direction for joining the laminated fiber layers constituting the three-dimensional fiber structure has a bent portion because the laminated fiber layer is inserted so as to penetrate the laminated fiber layer in a flat state. It can be easily inserted as compared with the case of inserting into the laminated fiber layer. Further, in the bending step, the primary structure is not held by simply pressing (pressing) the plate-shaped primary structure, but the primary structure is held by at least two holding members. The primary structure is moved relative to the primary structure by applying a pressing force via the pressing member while applying tension to the primary structure to move the holding member and the pressing member relative to each other so as to apply a bending force to the primary structure. Bending portions having different bending directions are formed at both ends of a portion (planar portion) sandwiched between the holding member and the pressing member . Since the bending directions of the bent portions formed at both ends of the flat portion are different, the cross-sectional shape of the three-dimensional fiber structure after the completion of the bending process by the virtual plane perpendicular to the center of curvature of the bent portion is in the thickness direction. The length of the contour line on one side is equal to the length of the contour line on the other side, and manufacturing is possible with the occurrence of wrinkles and distortion in the bent portion being suppressed.

  According to a second aspect of the present invention, in the first aspect of the invention, in the bending step, the bending process is performed in a state where one of the holding members that hold the primary structure is fixed. In the present invention, by controlling the movement of the other holding members based on the position of the fixed one holding member, the control becomes simpler than when each holding member is moved and bent.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, an odd number of holding members for holding the primary structure are provided, and bending is performed with the central holding member fixed. . Therefore, in the present invention, the bending process can be performed by moving the holding members located on both sides symmetrically with the fixed central holding member interposed therebetween.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the resin is impregnated and cured by a resin transfer molding (RTM) method. In this invention, compared with other impregnation and curing methods, the resin can be uniformly impregnated and cured in the three-dimensional fiber structure with high productivity.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the bending is performed with a curvature larger than the curvature of the bent portion in the fiber reinforced composite material in consideration of a springback. The bend is formed so that When the bending process is performed so that the curvature of the bending portion becomes the same as the bending portion of the fiber reinforced composite material in the bending process, the curvature of the bending portion becomes small because the obtained three-dimensional fiber structure is a springback. . However, in the present invention, bending is performed in consideration of the springback, so that the curvature of the bending portion of the obtained three-dimensional fiber structure is equivalent to the curvature of the bending portion in the fiber reinforced composite material.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein at least one of the continuous fibers and the thickness direction yarn has an elongation of 2.4% or less. . Compared to fibers (nylon, acrylic) that stretch 10% or more, the elongation at break of carbon fibers is generally 0.5% to 2.4%, and it is difficult to stretch and bend continuous fibers without slack. . However, in this invention, even if a carbon fiber is used for the continuous fiber, the bent portion can be formed without difficulty.

  According to the present invention, even if the flat fiber-like primary structure in which the laminated fiber layers are joined by the thread in the thickness direction is formed by bending, the generation of wrinkles and distortion in the bent portion is suppressed in a tertiary state. The manufacturing method of the fiber reinforced composite material provided with the bending process which can manufacture an original fiber structure can be provided.

(First embodiment)
Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1A, a three-dimensional fiber structure 11 as a reinforcing material of a fiber-reinforced composite material has an even number of laminated fiber layers 12 arranged so that continuous fibers are at least biaxially oriented. It is bent to have a part. The laminated fiber layer 12 is bent in the same bending direction as the bending portions 14a and 14b with different bending directions, the flat portion 15a with one end being a free end, and the flat portion 15b sandwiched between the bending portions 14a and 14b with different bending directions. It is formed in a three-dimensional plate shape including a flat portion 15c sandwiched between the portion 14a or the bent portion 14b. Specifically, the laminated fiber layer 12 is formed in a cross-sectional shape in which two so-called hat shapes are continuous at the heel portion, and the bent portion 14a is provided at a position corresponding to the ridge portion of the hat shape, The bent portion 14b is provided at a position corresponding to the top portion of the hat shape. That is, the laminated fiber layer 12 is formed in a three-dimensional plate shape having portions where the bent portions 14a and 14b having different bending directions are adjacent to each other with the plane portion 15b interposed therebetween. The laminated fiber layer 12 does not have the same cross-sectional shape in the plane perpendicular to the center of curvature of the bent portions 14a and 14b, and extends from one end side (the front side in FIG. 1A) to the other end side of the laminated fiber layer 12. The height of the hat portion is gradually increased. In addition, in Fig.1 (a), the three-dimensional fiber structure 11 is illustrated in the state in which the top part of a hat part becomes a lower side.

  As shown in FIG. 1 (b), the laminated fiber layers 12 are joined together by thickness direction threads 13 arranged in the thickness direction of the laminated fiber layers 12. The laminated fiber layer 12 has a shape of a portion formed by the bent portion 14a, the plane portion 15b, and the bent portion 14b in a cross section by a virtual plane orthogonal to the center of curvature of the bent portions 14a and 14b, for example, in FIG. In the shape formed by the line connecting ABCDE, the length of the outer line LG1 on one side in the thickness direction is equal to the length of the outer line LG2 on the other side. That is, the laminated fiber layer 12 has a cross-sectional shape by a virtual plane orthogonal to the center of curvature of the bent portions 14a and 14b, and the length of the outer line LG1 on one side in the thickness direction and the length of the outer line LG2 on the other side. Are formed in the same shape.

  As shown in FIG. 1 (c), the laminated fiber layer 12 includes a 0-degree fiber layer 12a as a fiber layer made of continuous fibers 16a having an arrangement angle of 0 ° and a fiber layer made of continuous fibers 16b having an arrangement angle of 90 °. 90 degree fiber layer 12b. In this specification, an arrangement angle of 0 ° means a state in which continuous fibers are arranged in parallel with the center line of curvature of the bent portions 14a and 14b, and an arrangement angle of 90 ° means that the continuous fibers are in the bent portions 14a and 14b. It means a state arranged so as to be orthogonal to the curvature center line. A plurality of 0 degree fiber layers 12 a and 90 degree fiber layers 12 b are alternately laminated to form a biaxially oriented laminated fiber layer 12. And the thickness direction thread | yarn 13 arranged in the thickness direction of the lamination | stacking fiber layer 12 is return | folded with the retaining thread 19, and each fiber layer is couple | bonded. As the continuous fiber and the thickness direction yarn 13, for example, carbon fiber is used. Carbon fiber has about 3000 to 24000 filaments.

Next, the manufacturing method of the fiber reinforced composite material which used the three-dimensional fiber structure 11 comprised as mentioned above as a reinforcing material is demonstrated.
The manufacturing method of the fiber reinforced composite material includes a continuous fiber arranging step, a thickness direction yarn inserting step, a bending step, and a resin impregnation curing step.

  In the continuous fiber arranging step, as shown in FIGS. 2A and 2B, a jig 18 in which pins 17a and 17b as restricting members are arranged at a predetermined pitch is used. The jig 18 is formed in a rectangular frame shape, and the pins 17a and 17b are detachably installed. The pitch of the pins 17a is set according to the direction perpendicular to the longitudinal direction of the jig 18, that is, the arrangement pitch of the continuous fibers 16a arranged at an arrangement angle of 0 °, and the pitch of the pins 17b is set in the longitudinal direction of the jig 18. In parallel, that is, in accordance with the arrangement pitch of the continuous fibers 16b arranged at an arrangement angle of 90 °.

  Then, as shown in FIG. 2 (b), continuous fibers 16a are arranged between the pins 17a so as to be engaged with the pins 17a and turned back on the jig 18, and 0 as a fiber layer having an arrangement angle of 0 °. The fiber layer 12a is formed. Further, as shown in FIG. 2A, the continuous fibers 16b are arranged between the pins 17b so as to engage with the pins 17b and bend back, thereby forming a 90-degree fiber layer 12b as a fiber layer having an arrangement angle of 90 °. Is done. Then, a plurality of 90 degree fiber layers 12b and 0 degree fiber layers 12a are alternately laminated to form a laminated fiber layer 12 having a biaxial orientation. 2A and 2B, the arrangement intervals of the continuous fibers 16a and 16b are widely illustrated, but the continuous fibers 16a and 16b are arranged in a state where the adjacent continuous fibers 16a and 16b are in contact with each other. .

  After the continuous fiber arranging step, the thickness direction yarn inserting step is performed in a state where the laminated fiber layer 12 is held by the jig 18. Insertion of the thickness direction thread | yarn 13 is performed similarly to the method currently disclosed by patent document 1, for example. More specifically, in the thickness direction of the laminated fiber layer 12, an insertion needle (not shown) having a hole at the tip and hooking the thickness direction thread 13 into the hole is inserted. The insertion needle advances until the hole in which the thickness direction thread 13 is hooked penetrates the laminated fiber layer 12. Thereafter, the insertion needle is slightly retracted. As a result, the thickness direction thread 13 is in a state where a U-shaped loop is formed.

  Next, the stopper thread needle (not shown) stops when it passes through the U-shaped loop and reaches the end of the laminated fiber layer 12. At this time, the retaining thread 19 (shown in FIG. 1C) is hooked on the tip of the retaining thread needle. Then, the retaining thread needle is pulled back, and the retaining thread 19 is inserted into the U-shaped loop of the thickness direction thread 13. In this state, the insertion needle is pulled back, the retaining thread 19 is tightened by the thickness direction thread 13, and the laminated fiber layer 12 is bonded. When the insertion of the thickness direction thread 13 into the laminated fiber layer 12 is completed, a flat primary structure (preform) 20 in which the 0 degree fiber layer 12a and the 90 degree fiber layer 12b are bonded with the thickness direction thread 13 is formed. It is formed. The thickness direction thread 13 is inserted into the laminated fiber layer 12 in parallel with the thickness direction thereof, that is, perpendicular to the laminated fiber layer 12 when the laminated fiber layer 12 is in a flat plate shape, and therefore has a bent portion. It can be easily inserted as compared with the case of inserting into the fiber layer.

  Next, a bending step of forming bent portions 14a and 14b at predetermined positions of the flat primary structure 20 into which the thickness direction thread 13 is inserted is performed. The three-dimensional fiber structure 11 is formed so that the cross-sectional shape of the hat portion gradually increases from the one end side (the near side in FIG. 1A) toward the other end side. In the unfolded state, it becomes a flat fan shape instead of a flat rectangular shape. Therefore, as the primary structure 20, bending is performed using the primary structure 20 in which the peripheral edge of the rectangular primary structure 20 is cut and formed in a fan shape as shown in FIG.

  In the bending step, a part of the primary structure 20 is held by at least two holding members, and the holding member is relatively moved so as to apply a bending force while applying tension to the primary structure 20, and the relative movement is performed. Bending portions 14a and 14b having different bending directions are formed at both ends of the primary structure 20 sandwiched between the holding members.

  In this embodiment, as shown to Fig.3 (a)-(c), the 1st holding member 21 holding the center of the primary structure 20 as a holding member, and the 2nd holding the both ends of the primary structure 20 are shown. A holding member 22 and a pressing member 23 for applying a pressing force while holding the primary structure 20 are provided. That is, an odd number of holding members that hold the primary structure 20 are provided. The first holding member 21 is fixed to the center of the primary structure 20, the second holding member 22 is fixed to both ends of the primary structure 20, and the pressing member 23 is between the first holding member 21 and the second holding member 22. Are fixed to the intermediate part (central part) of the primary structure 20.

  The first holding member 21, the second holding member 22, and the pressing member 23 are detachably fixed to the upper surface of the primary structure 20 through, for example, pins. When the bending process is performed in the bending process, the first holding member 21, the second holding member 22, and the pressing member 23 have contact surfaces with the primary structure 20 so as not to slip between the primary structure 20. It is preferable that the frictional resistance is large. As a configuration for increasing the frictional resistance, for example, there is a lining made of a material having a high frictional resistance such as rubber.

  3B, the first holding member 21 is fixed, and the second holding member 22 is pressed in a state where tension is applied to the primary structure 20 in the same plane as the first holding member 21. The member 23 is moved downward so as to apply a pressing force to the primary structure 20 to be bent. The second holding member 22 moves in the same plane from the start to the end of the bending process in a state where tension is applied to the primary structure 20.

  As shown by the chain line in FIG. 3C and FIG. 4, the pressing member 23 exists on the same plane as the plane where the first holding member 21 and the second holding member 22 are located at the start of bending. However, after starting the bending process, that is, after pressing, it is inclined with respect to the plane on which the first holding member 21 and the second holding member 22 are located, and in this embodiment, it is inclined downward from one end side toward the other end side. Moved. Then, the pressing surface of the pressing member 23 is moved so that the pressing surface is positioned on a plane that forms a predetermined angle with the plane where the first holding member 21 and the second holding member 22 are positioned when the bending process is completed. Further, the pressing member 23 is not parallel to the first holding member 21 but at a predetermined angle as indicated by a chain line at the start of bending. However, after the bending process is started, the first holding member 21 is gradually moved so as to become parallel to the first holding member 21, and when the bending process is completed, as shown by the solid line in FIG. 21 is arranged in a state parallel to 21.

  On the other hand, the second holding member 22 is not parallel to the first holding member 21 but at a predetermined angle at the start of bending as shown by the chain line in FIGS. . Then, after the bending process is started, the pressing member 23 is gradually moved so as to approach parallel to the first holding member 21. When the bending process is completed, the solid line in FIGS. As shown, the first holding member 21 is arranged in parallel.

  More specifically, the pressing force is applied to the intermediate structure of the first holding member 21 and the second holding member 22 with respect to the primary structure 20 with the height of the first holding member 21 and the second holding member 22 held constant. Bending is performed using a shaping apparatus capable of imparting.

  As shown in FIGS. 5A and 5B, the shaping device used for bending includes a pair of clamping devices 24 and 25 that can grip the end of the primary structure 20 together with the first holding member 21. ing. The clamp devices 24 and 25 include a horizontally disposed air cylinder 26 and a grip portion 27 provided at the tip of the piston rod 26a. The clamp devices 24 and 25 are configured to be capable of pulling the primary structure 20 with a predetermined range of tension by the air cylinder 26 in a state where the end portion of the primary structure (preform) 20 is gripped by the grip portion 27. Yes.

  The shaping apparatus includes a fixing portion 28 that fixes the first holding member 21 to the same height as the second holding member 22. By the operation of the air cylinder 29, the first holding member 21 can be switched between a state in which the first holding member 21 is fixed to the fixing portion 28 and a state in which the first holding member 21 can be released.

  In addition, the shaping device includes a mechanism that can apply a pressing force to the primary structure 20 held by the grip portion 27 and the fixing portion 28 via the pressing member 23. As shown in FIG. 4, the mechanism for applying the pressing force includes a support shaft 30 that can be rotated in a plane, and an arm 31 that is rotatably supported with respect to the support shaft 30. A cylinder 32 (shown in FIGS. 5A and 5B) for applying a pressing force to the fixed pressing member 23 is provided. The cylinder 32 presses the pressing member 23 via the piston rod 32a, and is moved in the horizontal direction in synchronization with the rotation of the support shaft 30 in a plane, and there is no problem even if the pressing member 23 is rotated. It is configured to be able to give a pressing force without any. The pressing member 23 is moved by the operation of the cylinder 32 to a standby position and an operating position for pressing the primary structure 20 held by a predetermined range of tension applied by the clamping devices 24 and 25. . In FIG. 4, only the support shaft 30 and the arm 31 for one pressing member 23 are shown.

The shaping apparatus includes a fixed mold 33 having a mold surface 33a corresponding to the outer shape of the bent part 14b at the top of the hat part of the three-dimensional fiber structure 11 to be formed.
As shown in FIG. 5A, the bending of the primary structure 20 is performed by gripping both ends of the primary structure 20 with the gripping portions 27 of the clamping devices 24 and 25, and the center of the primary structure 20 with the fixing portion 28. A state in which a predetermined range of tension is applied to the primary structure 20 in the horizontal direction with the portion fixed. In addition, the cylinder 32 is disposed at a bending start position facing each pressing member 23, and the tip of the piston rod 32 a is disposed in contact with the pressing member 23. In this state, the cylinder 32 is operated to rotate the pressing member 23 downward. A pressing force is applied to the primary structure 20 by the pressing member 23 as the pressing member 23 rotates downward. The pressing member 23 is also rotated in a plane where the pressing member 23 exists along with the downward rotation.

  As the intermediate portion between the first holding member 21 and the second holding member 22 of the primary structure 20 is pressed downward by the pressing member 23 and moved, the protruding amount of the piston rod 26a of the air cylinder 26 increases. The interval between the gripping portions 27 is reduced. That is, both the second holding members 22 applying horizontal tension to the primary structure 20 at a certain height position move in the same plane so as to approach the first holding member 21. The air cylinder 26 does not actively move the second holding member 22 (gripping part 27), but the position of the gripping part 27 is set so that an excessive force does not act on the primary structure 20 by the downward movement of the pressing member 23. Moved.

  In a state where the first holding member 21 and the second holding member 22 are applying horizontal tension to the primary structure 20 at a certain height position, the intermediate portion is pressed downward by the pressing member 23 and moves downward. . The primary structure 20 includes a bent portion 14a having different bending directions at both ends of the portion sandwiched between the second holding member 22 and the pressing member 23 and the portion sandwiched between the pressing member 23 and the first holding member 21. , 14b are formed. When the primary structure 20 is bent, the length is different between the inner path and the outer path when viewed only by the bent portion. If a deviation occurs in the 0 degree fiber layer 12a and the 90 degree fiber layer 12b so as to absorb this path difference, the bending process is performed without generating wrinkles or distortion inside the bent parts 14a and 14b. Become. The primary structure 20 is held by the first holding member 21 and the second holding member 22 and receives a pressing force in the vertical direction by the pressing member 23 in a state where a certain range of tension is applied in the horizontal direction. The layer 12a and the 90-degree fiber layer 12b are easily displaced. Further, the primary structure 20 has both bent portions 14a and 14b having different bending directions sandwiched between the second holding member 22 and the pressing member 23, and both ends of the portion sandwiched between the pressing member 23 and the first holding member 21. Therefore, the portion corresponding to the shift on the inner side of the one bent portion 14a is deformed so that it is absorbed by the shift on the outer side of the other bent portion 14b.

  The three-dimensional fiber structure 11 configured as described above is impregnated and cured with a resin in a resin impregnation and curing step to form a fiber reinforced composite material (fiber reinforced resin). For resin impregnation and curing, for example, a resin transfer molding (RTM) method is employed. In the RTM method, a three-dimensional fiber structure 11 is disposed in a resin-impregnated mold (molding die), and in this state, a thermosetting matrix resin is injected into the resin-impregnated mold. After the fiber 11 is impregnated, a fiber-reinforced composite material is produced by heating and curing. For example, an epoxy resin is used as the thermosetting resin. After the bending process is completed, the three-dimensional fiber structure 11 is conveyed into the mold without removing the first holding member 21, the second holding member 22, and the pressing member 23, and then the first holding member 21 and the second holding member. 22 and the pressing member 23 are removed from the three-dimensional fiber structure 11. In the state in which the three-dimensional fiber structure 11 is accommodated in the mold, the curvature of the bent portions 14a and 14b is smaller than that in the bent state by the spring back, but the desired curvature state is obtained by closing the mold. .

  When the primary structure 20 is bent using a length of approximately 150 mm and a laminated fiber layer of 30 layers, the three-dimensional fiber structure is in a state in which wrinkles and distortion are suppressed inside the bent portion. 11 was obtained.

  1 to 5 schematically illustrate the configuration of the three-dimensional fiber structure 11, the primary structure 20, or the shaping device, and some dimensions are exaggerated for the convenience of illustration. For the sake of clarity, the ratio of dimensions such as the width, length, and thickness of each part is different from the actual ratio. Also, depending on the figure, the ratio of dimensions such as the width, length, and thickness of each part may be different.

According to this embodiment, the following effects can be obtained.
(1) The manufacturing method of a fiber reinforced composite material is provided with the continuous fiber arrangement | sequence process, the thickness direction thread | yarn insertion process, the bending process, and the resin impregnation hardening process. In the bending step, the first holding member 21 and the second holding member 22 hold the primary structure 20 while applying tension, and the bending portion is bent by the pressing member 23 at an intermediate portion between the first holding member 21 and the second holding member 22. The first holding member 21, the second holding member 22, and the pressing member 23 are moved relative to each other so as to apply a force. And the bending part 14a, 14b from which a bending direction differs in the both ends of the part pinched | interposed into the 2nd holding member 22 and the press member 23 of the primary structure 20, and the press member 23 and the 1st holding member 21. Form. Therefore, unlike the case where the flat primary structure 20 is simply pressed (pressed) and bent, it is possible to manufacture the three-dimensional fiber structure 11 in which the generation of wrinkles and distortions in the bent portions 14a and 14b is suppressed, A fiber-reinforced composite material using such a three-dimensional fiber structure 11 as a reinforcing material can be manufactured.

  (2) In the bending step, bending is performed with one of the holding members (first holding member 21) holding the primary structure 20 fixed. Accordingly, by controlling the movement of the other holding members (the second holding member 22 and the pressing member 23) based on the position of the fixed one holding member (the first holding member 21), each holding member is moved. Control is easier than bending.

  (3) An odd number of holding members for holding the primary structure 20 are provided, and bending is performed with the central holding member (first holding member 21) fixed. Therefore, the bending process can be easily performed by moving the holding members (the second holding member 22 and the pressing member 23) located on both sides of the fixed central first holding member 21 symmetrically.

  (4) In the bending step, a first holding member 21 that holds the center of the primary structure 20 and a second holding member 22 that holds both ends of the primary structure 20 are provided, and the second holding member 22 is the primary The structure 20 is provided so as to be movable in the same plane from the start to the end of bending in a state where tension is applied to the structure 20. And in the intermediate part of the 1st holding member 21 and the 2nd holding member 22, it is in the state where the pressing surface of the pressing member 23 does not move with respect to the primary structure 20 with respect to the primary structure 20 via the pressing member 23. Bending is performed by applying a pressing force. Therefore, even the three-dimensional fiber structure 11 having a complicated cross-sectional shape such as a cross-sectional shape having a continuous hat shape can be easily manufactured in a state where generation of wrinkles and distortions in the bent portions 14a and 14b is suppressed. become.

  (5) The primary structure 20 is formed in a substantially fan-shaped plane, and the pressing member 23 has a pressing surface on a plane that forms a predetermined angle with the plane where the first holding member 21 and the second holding member 22 are located when the bending process is completed. Moved to be located at Accordingly, the cross-sectional shapes of the bent portions 14a and 14b in the plane orthogonal to the center line of curvature are not the same, and the three-dimensional shape having a more complicated shape such that the height of the hat portion gradually increases from one end to the other end side. Even the fiber structure 11 can be easily manufactured.

  (6) Resin impregnation and curing in the resin impregnation curing step are performed by a resin transfer molding (RTM) method. Therefore, compared to other impregnation and curing methods, the three-dimensional fiber structure 11 can be uniformly impregnated and cured with resin with high productivity.

  (7) The RTM method in a state in which the three-dimensional fiber structure 11 after completion of the bending process is held by the first holding member 21 or the like without removing the first holding member 21, the second holding member 22, and the pressing member 23. Then, the first holding member 21, the second holding member 22, and the pressing member 23 are removed from the three-dimensional fiber structure 11. Therefore, it becomes easy to convey the three-dimensional fiber structure 11 while maintaining the bending state.

  (8) Carbon fibers are used as the continuous fibers 16a and 16b. Since the elongation rate of the carbon fiber is generally 0.5 to 2.4%, when the primary fiber 20 is bent, the 0-degree fiber layer 12a and the 90-degree fiber layer 12b are not smoothly displaced. Although wrinkles and distortion are likely to occur inside the bent portion, in this embodiment, the bent portion can be formed without difficulty even if carbon fiber is used as the continuous fiber.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The planar fan-shaped primary structure 20 is formed by laminating fiber layers in a continuous fiber arraying process, with the jig 18 having a fan-shaped frame instead of cutting the periphery of the rectangular primary structure 20. 12 may be formed in a fan shape.

  In the bending process, the bending portions 14a and 14b of the three-dimensional fiber structure 11 may be formed so as to have a curvature larger than the curvature of the bending portion in the fiber reinforced composite material in consideration of the spring back. When bending is performed so that the curvature of the bent portions 14a and 14b is the same as the curvature of the bent portion in the fiber reinforced composite material in the bending process, the obtained three-dimensional fiber structure 11 is spring-back, and thus the bent portion 14a. , 14b has a smaller curvature. However, when bending is performed so that the curvature of the bending portion of the fiber reinforced composite material is larger than that of the bending portion of the fiber reinforced composite material in consideration of the springback, the curvature of the bending portions 14a and 14b of the obtained three-dimensional fiber structure 11 is the fiber reinforced composite. A material equivalent to the curvature of the bent portion of the material is obtained.

  The three-dimensional fiber structure 11 is not limited to a shape in which the height of the hat portion gradually increases from one end to the other end side, and the cross-sectional shape is constant from one end to the other end side. Also good. In that case, a planar rectangular body is used as the primary structure 20, and the pressing member 23 moves downward while maintaining a state parallel to the first holding member 21 and the second holding member 22. 2 The holding member 22 moves so as to approach the first holding member 21 in a state parallel to the first holding member 21.

  ○ The laminated fiber layer 12 is not limited to a configuration in which the 0-degree fiber layers 12a and the 90-degree fiber layers 12b are alternately laminated, and a configuration in which at least biaxial orientation is formed by laminating fiber layers made of continuous fibers. If it is. For example, in addition to the 0 degree fiber layer 12a made of continuous fibers 16a having an arrangement angle of 0 ° and the 90 degree fiber layer 12b made of continuous fibers 16b having an arrangement angle of 90 °, the arrangement angles are + 45 ° and −45 °. It is good also as a structure used as the 4-axis orientation which has the bias fiber layer which consists of continuous fibers (bias fiber). Alternatively, triaxial orientation may be achieved by a combination of continuous fibers 16a having an arrangement angle of 0 ° and bias fibers, or a combination of continuous fibers 16b having an arrangement angle of 90 ° and bias fibers.

  ○ The laminated fiber layer 12 is not limited to a configuration in which fiber layers made of continuous fibers having different arrangement angles are alternately laminated, and there is a portion in which a plurality of fiber layers made of continuous fibers having the same arrangement angle are laminated successively. It is good also as a structure.

  ○ The three-dimensional fiber structure 11 includes a laminated fiber layer 12 in which fiber layers made of continuous fibers are laminated to be at least biaxially oriented, and bent portions 14a and 14b having different bending directions are adjacent to each other with a plane portion 15b therebetween. It is only necessary that the thickness direction yarns 13 are arranged in a state of intersecting with each fiber layer of the laminated fiber layer 12 while being formed in a three-dimensional plate shape having adjacent portions in the state. Further, the number of holding members used in the bending process varies depending on the shape of the three-dimensional fiber structure 11 to be formed, and a bending force is applied to the primary structure 20 while applying tension to the primary structure 20. It is sufficient that the holding member can be moved relative to each other, and it is sufficient that there are at least two holding members. For example, as shown in FIG. 6A, the cross-sectional hat-shaped three-dimensional fiber structure 11, and as shown in FIG. 6B, two bent portions 14a and 14b and three plane portions 15a, The three-dimensional fiber structure 11 having a crank shape in cross section 15b may be used. The three-dimensional fiber structure 11 having a cross-sectional hat shape uses one side of the shaping device when manufacturing the three-dimensional fiber structure 11 having a continuous hat shape, or a shaping device having the same configuration as the one side Or can be manufactured. Further, the three-dimensional fiber structure 11 having a crank shape in cross section is formed by performing bending so as to move both ends relatively while applying tension while holding both ends of the primary structure 20. These three-dimensional fiber structures 11 are also used as a composite material by impregnating and curing a resin.

  ○ The three-dimensional fiber structure 11 is formed in a three-dimensional plate shape in which a laminated fiber layer 12 having at least biaxial orientation in which fiber layers made of a woven fabric structure are laminated, and a bent part and a flat part are continuous. A configuration in which the thickness direction yarns 13 are arranged in a state of crossing each fiber layer of the laminated fiber layer 12 may be employed. That is, the three-dimensional fiber structure 11 may have a configuration in which laminated fabrics are joined by the thickness direction yarns 13. In this case, when the three-dimensional fiber structure 11 is manufactured, a woven fabric laminating step of laminating woven fabrics is performed instead of the continuous fiber arranging step. The other steps, that is, the thickness direction yarn insertion step and the bending step of forming a bent portion at a predetermined position of the flat plate-like primary structure 20 in which the thickness direction yarn 13 is inserted are performed in the same manner as in the above embodiment. As the woven fabric, for example, a plain woven fabric is used, but a multilayer woven fabric such as a double woven fabric, a triple woven fabric, or an air woven fabric may be laminated. In this case, the laminated fiber layer 12 can be formed in a shorter time than the laminated fiber layer 12 is formed by laminating fiber layers in which continuous fibers are arranged.

  Even if it applies to manufacture of the three-dimensional fiber structure 11 of the shape from which the height of the plane part 15a with a free end and the plane part 15c pinched | interposed into the bending part 14a or the bending part 14b of the same bending direction differs. Good. In that case, the bending process is started from a state in which the first holding member 21 and the second holding member 22 exist on the same plane, and the second holding member 22 has a height different from that of the first holding member 21 during the bending process. Move to become.

  ○ The pressing member 23 is not limited to a rectangular shape. For example, as shown in FIG. 7, the pressing member 23 may be formed in a trapezoidal shape. The first holding member 21 and the second holding member 22 are formed in a rectangular shape. In this case, the three-dimensional fiber structure 11 is shaped so that the height of the hat portion gradually increases from one end to the other end side, and the width of the hat portion gradually decreases.

The continuous fiber constituting the laminated fiber layer 12 is not limited to carbon fiber, and aramid fiber, glass fiber, or the like may be used according to the physical properties required for the three-dimensional fiber structure 11.
In the thickness direction thread insertion step, the thickness direction thread 13 may be inserted into the laminated fiber layer 12 so as to penetrate the laminated fiber layer 12, and is not necessarily limited to the state orthogonal to the laminated fiber layer 12, but is slightly inclined. You may insert in the state.

The thermosetting resin used for the composite material using the three-dimensional fiber structure 11 as a reinforcing material is not limited to an epoxy resin, and an unsaturated polyester resin, a phenol resin, or the like may be used.
A thermoplastic resin may be used in place of the thermosetting resin as the matrix resin constituting the composite material using the three-dimensional fiber structure 11 as a reinforcing material. When a thermoplastic resin is used as the matrix resin, the laminated fiber group is impregnated with a thermoplastic resin by a general impregnation method such as a melt impregnation molding method and then cooled to form a composite material. As the thermoplastic resin, for example, nylon, polybutylene terephthalate, polycarbonate or the like is used.

The following technical idea (invention) can be understood from the embodiment.
(1) In the invention according to claim 3, in the bending step, a first holding member that holds the center of the primary structure as the holding member, and a second holding member that holds both ends of the primary structure. The second holding member is provided to be movable in the same plane from the start to the end of bending in a state in which tension is applied to the primary structure, and the first holding member and the second holding member Bending is performed by applying a pressing force to the primary structure at the intermediate portion through the pressing member and with the pressing surface of the pressing member not moving relative to the primary structure.

  (2) In the invention described in the technical idea (1), the primary structure is formed in a substantially fan shape, and the pressing surface of the pressing member is a plane on which the second holding member is positioned when bending is completed. And is moved so as to be positioned on a plane forming a predetermined angle.

  (3) In the invention according to claim 4, the three-dimensional fiber structure formed in the invention according to any one of claims 1 to 3 and the technical ideas (1) and (2) After being conveyed to the inside of the mold while being held by the holding member, the holding member is removed from the three-dimensional fiber structure.

(4) A three-dimensional structure in which a laminated fiber layer having at least biaxial orientation in which fiber layers made of a woven fabric are laminated has a portion in which bending portions having different bending directions are adjacent to each other with a plane portion in between. And a method for producing a fiber-reinforced composite material using a three-dimensional fiber structure in which thickness direction threads are arranged in a state intersecting with each fiber layer of the laminated fiber layer as a reinforcing material. And
A fabric laminating step of laminating fabrics to form a laminated fiber layer that is at least biaxially oriented;
A thickness direction thread insertion step of forming a flat primary structure by inserting a thickness direction thread into the laminated fiber layer so as to penetrate the laminated fiber layer;
A bending step of forming a bent portion at a predetermined position of the flat primary structure into which the thickness direction thread is inserted;
A resin-impregnated curing step in which the primary structure after being bent in the bending step is placed in a mold and impregnated and cured with a resin; and
In the bending step, the holding member is relatively moved so that a part of the primary structure is held by at least two holding members and a bending force is applied to the primary structure while applying tension to the primary structure. And bending portions having different bending directions are formed at both ends of the primary structure sandwiched between the holding members that move relative to each other.

(A) is a schematic perspective view of the three-dimensional fiber structure in one embodiment, (b) is a schematic diagram showing the relationship between a bent portion having a different bending direction and a plane portion sandwiched between both bent portions, and (c) is a primary view. The schematic cross section which shows the relationship between the laminated fiber layer of a structure, and a thickness direction thread | yarn. (A), (b) is a schematic top view which shows the arrangement | sequence state of a jig | tool and a continuous fiber, (c) is a perspective view of the primary structure which gave the external shape process. (A)-(c) is a model perspective view which shows the procedure of a bending process. The model perspective view explaining a bending process. (A), (b) is a schematic diagram which shows the relationship between a shaping apparatus, a primary structure, and a three-dimensional fiber structure. (A) is a schematic perspective view of the three-dimensional fiber structure of another embodiment, (b) is a schematic diagram of the three-dimensional fiber structure of another embodiment. The schematic plan view which shows the primary structure of another embodiment, a press member, etc. FIG. The schematic diagram which shows a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Three-dimensional fiber structure, 12 ... Laminated fiber layer, 12a ... 0 degree fiber layer as a fiber layer, 12b ... 90 degree fiber layer as a fiber layer, 13 ... Thickness direction thread | yarn, 14a, 14b ... Bending part, 15a, 15b, 15c ... plane part, 16a, 16b ... continuous fiber, 17a, 17b ... pin as regulating member, 18 ... jig, 20 ... primary structure, 21 ... first holding member as holding member, 22 ... A second holding member as a holding member, 23... A pressing member as a holding member.

Claims (6)

A three-dimensional plate in which a laminated fiber layer having at least biaxial orientation, in which fiber layers made of continuous fibers are laminated, has a portion in which bending portions having different bending directions are adjacent to each other with a plane portion interposed therebetween. A method for producing a fiber-reinforced composite material using a three-dimensional fiber structure in which thickness direction yarns are arranged in a state intersecting with each fiber layer of the laminated fiber layer as a reinforcing material,
At least biaxial orientation is obtained by laminating a fiber layer formed by arranging continuous fibers between the regulating members so that the regulating members are folded and engaged with the regulating members on a jig in which the regulating members are arranged at a predetermined pitch. A continuous fiber array process for forming a laminated fiber layer;
A thickness direction thread insertion step of forming a flat primary structure by inserting a thickness direction thread into the laminated fiber layer so as to penetrate the laminated fiber layer;
A bending step of forming a bent portion at a predetermined position of the flat primary structure into which the thickness direction thread is inserted;
A resin-impregnated curing step in which the primary structure after being bent in the bending step is placed in a mold and impregnated and cured with a resin; and
In the bending step, while holding a part of the primary structure with at least two holding members and applying tension to the primary structure, a pressing member is applied to the primary structure at an intermediate portion of the holding member. The holding member and the pressing member are relatively moved so as to apply a pressing force to apply a bending force to the primary structure, and the primary structure sandwiched between the holding member and the pressing member that move relative to each other. A method for producing a fiber-reinforced composite material, wherein bent portions having different bending directions are formed at both ends.   The method for producing a fiber-reinforced composite material according to claim 1, wherein in the bending step, bending is performed in a state in which one of the holding members that hold the primary structure is fixed.   The manufacturing method of the fiber reinforced composite material according to claim 1, wherein an odd number of holding members for holding the primary structure are provided, and bending is performed in a state where the central holding member is fixed.   The method for producing a fiber-reinforced composite material according to any one of claims 1 to 3, wherein the resin is impregnated and cured by a resin transfer molding (RTM) method.   The fiber-reinforced composite according to any one of claims 1 to 4, wherein in the bending process, the bent portion is formed so as to have a curvature larger than the curvature of the bent portion in the fiber-reinforced composite material in consideration of a springback. A method of manufacturing the material.   The method for producing a fiber-reinforced composite material according to any one of claims 1 to 5, wherein at least one of the continuous fibers and the thickness direction yarn has an elongation percentage of 2.4% or less.

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