Method of manufacturing curved UD prepreg tape

Abstract

Provided is a method whereby unidirectional (UD) prepreg tape can be bent into curves, with no occurrence of defects, so as to have uniform thickness and width running lengthwise along the tape.　In this method of manufacturing curved UD prepreg tape, a deformation site that is between two boundary sections that are in positions symmetrical with respect to a lengthwise midsection of a linear UD prepreg tape is shear-deformed along the UD prepreg tape lengthwise, such that an operation, in which non-deformed sites that are more to the end-section sides of the UD prepreg tape than the two boundary sections are displaced in mutually opposite directions traversing the UD prepreg tape lengthwise, is reiterated while the positions of the two boundary sections are shifted from the end-section sides toward the midsection of the UD prepreg tape.

Description

Manufacturing method for curved UD prepreg tape

[0001] The present disclosure relates to a method for manufacturing a curved UD prepreg tape.

[0002] Among the products manufactured from fiber-reinforced composite materials, UD (Uni-Directional) prepreg is used for structures that require particularly high specific strength. UD prepreg is a material in which reinforcing fibers aligned in one direction are impregnated with a matrix resin. By designing the orientation of these reinforcing fibers, a high specific strength can be achieved.

[0003] However, currently, in order to laminate UD prepregs to form structures with free-form or curved shapes, it is necessary to cut the UD prepregs in the direction of cutting the reinforcing fibers and then patchwork them to form the desired shape, which prevents the above-mentioned advantages of UD prepregs from being fully utilized.

[0004] Alternatively, if the reinforcing fibers of the UD prepreg tapes are not cut and the tapes are laminated in the shape described above while maintaining their linear shape, gaps and / or overlaps will occur between two adjacent UD prepreg tapes, which can cause defects after molding.

[0005] To avoid this, the UD prepreg tapes must be curved and arranged so that neither a gap nor an overlap occurs between two adjacent UD prepreg tapes when they are stacked on the mold.

[0006] Furthermore, by laminating and molding curved UD prepregs so that the reinforcing fibers are oriented in the direction of the stress acting on the structure, it is possible to manufacture structures with higher specific strength.

[0007] Conventionally, there have been the following methods for bending UD prepregs.

[0008] The first method is to offset the difference in circumferential length between the inner and outer peripheries of the curved portion by undulating the reinforcing fibers in-plane or out-of-plane. In this case, since the undulation of the reinforcing fibers can cause defects after molding, it is desirable to use a UD prepreg tape with a small width (i.e., thin) to minimize this. This is because a UD prepreg tape with a small width has a small difference in circumferential length between the inner and outer peripheries of the curved portion. However, even when a UD prepreg tape with a small width is used, defects caused by undulation cannot be completely eliminated. Nevertheless, there is a problem that the number of UD prepreg tapes required increases, resulting in increased manufacturing costs.

[0009] The second method involves approximating the curved portion as a series of parallelogram sections arranged along the centerline of the curved portion, and repeatedly forming each parallelogram section by shearing a linear UD prepreg tape in a direction perpendicular to its longitudinal direction. This method eliminates in-plane or out-of-plane undulations of the reinforcing fibers, eliminating defects caused by undulations, as in the first method. However, shear deformation not only changes the thickness of the UD prepreg tape, but also changes the width of the UD prepreg tape perpendicular to the centerline of the curved portion. This results in a problem of uneven thickness and width along the longitudinal direction of the completed curved UD prepreg tape. Furthermore, in principle, it is impossible to bend the prepreg tape more than 90° from the longitudinal direction at the start of curvature.

[0010] As described above, with conventional methods, it has been virtually impossible to curve a UD prepreg tape so that it has a uniform thickness and width along its longitudinal direction without causing defects.

[0011] The present disclosure has been made in view of the above-mentioned problems, and aims to provide a method by which a UD prepreg tape can be curved so as to have a uniform thickness and width along its longitudinal direction without generating defects.

[0012] In order to solve the above problems, in the manufacturing method of a curved UD prepreg tape of the present disclosure, a deformed area between two boundary areas that are located symmetrically with respect to the center in the longitudinal direction of a linear UD prepreg tape is shear-deformed in the longitudinal direction of the UD prepreg tape, thereby displacing a non-deformed area that is closer to the end of the UD prepreg tape than the two boundary areas in opposite directions across the longitudinal direction of the UD prepreg tape. This operation is repeated while moving the positions of the two boundary areas from the end sides to the center of the UD prepreg tape.

[0013] According to the present disclosure, UD prepreg tape can be curved to have uniform thickness and width along its length without defects.

[0014] It is a schematic explanatory diagram showing the basic principle of the method of the present disclosure, showing a linear unidirectional (UD) prepreg tape which is a material for manufacturing a curved UD prepreg tape. It is a schematic explanatory diagram showing the basic principle of the method of the present disclosure, showing the state before deformation of a deformation site to be shear deformed among UD prepreg tapes. It is a schematic explanatory diagram showing the basic principle of the method of the present disclosure, showing the state after deformation of the deformation site. It is a schematic explanatory diagram showing the basic principle of the method of the present disclosure, showing the finally obtained curved UD prepreg tape. It is a schematic explanatory diagram showing the first embodiment of the method of the present disclosure, showing a linear UD prepreg tape which is a material for manufacturing a curved UD prepreg tape. It is a schematic explanatory diagram showing the first embodiment of the method of the present disclosure, showing a state where frustum-shaped rollers are arranged at each of two end portions in the longitudinal direction of the UD prepreg tape. It is a schematic explanatory diagram showing the first embodiment of the method of the present disclosure, showing a situation where due to the rotation of the two rollers, a deformation site between the two boundary portions undergoes shear deformation, and as a result, two non-deformed portions between each boundary portion and the end portion of the UD prepreg tape rotate and displace in opposite directions crossing the longitudinal direction. It is a schematic explanatory diagram showing the first embodiment of the method of the present disclosure, showing a situation where the operation shown in FIG. 2C is repeated while moving the positions of each of the two boundary portions toward the central portion of the UD prepreg tape at an equal speed. It is a schematic explanatory diagram showing the first embodiment of the method of the present disclosure, showing the finally obtained curved UD prepreg tape. It is a schematic explanatory diagram showing the first modification example of the first embodiment of the method of the present disclosure, showing a linear UD prepreg tape which is a material for manufacturing a curved UD prepreg tape. It is a schematic explanatory diagram showing the first modification example of the first embodiment of the method of the present disclosure, showing a state where frustum-shaped rollers are arranged at each of two end portions in the longitudinal direction of the UD prepreg tape.3C is a schematic explanatory diagram showing a first modified example of the first embodiment of the method of the present disclosure, illustrating a state in which the operation of shearing the deformation region between two boundaries by rotating two rollers is repeated while moving the positions of each of the two boundaries toward the center of the UD prepreg tape at an equal speed, until the two boundaries reach the curvature boundaries at the two curved portions of the finally obtained curved UD prepreg tape. 3D is a schematic explanatory diagram showing a first modified example of the first embodiment of the method of the present disclosure, illustrating a state after the two rollers in FIG. 3C have been shifted the same distance in the direction of their respective rotation axes (directions in which the diameters decrease). 3E is a schematic explanatory diagram showing a first modified example of the first embodiment of the method of the present disclosure, illustrating a state in which the operation of shearing the deformation region between two boundaries by rotating two rollers is repeated while moving the positions of each of the two boundaries toward the center of the UD prepreg tape at an equal speed. 3F is a schematic explanatory diagram showing a first modified example of the first embodiment of the method of the present disclosure, illustrating a state in which the finally obtained curved UD prepreg tape is repeated.

[0023] Fig. 1 is a schematic explanatory diagram showing a second modified example of the first embodiment of the method of the present disclosure, illustrating a straight UD prepreg tape that serves as a material for producing a curved UD prepreg tape. Fig. 2 is a schematic explanatory diagram showing a state in which a truncated cone-shaped roller is disposed at each of the two longitudinal ends of the UD prepreg tape. Fig. 3 is a schematic explanatory diagram showing a second modified example of the first embodiment of the method of the present disclosure, illustrating a state in which the operation of shearing the deformation region between two boundaries by rotating the two rollers is repeated while moving each of the positions of the two boundaries toward the center of the UD prepreg tape at an equal speed, until the two boundaries reach the shape boundary between the arc-shaped portion and the straight portion of one of the two curvature portions that constitute the two curved portions of the finally obtained curved UD prepreg tape. FIG. 10 is a schematic explanatory diagram showing a second variant of the first embodiment of the method of the present disclosure, illustrating the situation after the two rollers have been moved to the curvature boundary between two curvature portions that constitute the two curved portions of the final curved UD prepreg tape.

[0023] Fig. 1 is a schematic explanatory diagram showing a second modified example of the first embodiment of the method of the present disclosure, illustrating a situation in which the operation of shearing the deformed region between two boundaries by rotating two rollers is repeated while moving the positions of each of the two boundaries toward the center of the UD prepreg tape at an equal speed. Fig. 2 is a schematic explanatory diagram showing a second modified example of the first embodiment of the method of the present disclosure, illustrating the final curved UD prepreg tape. Fig. 3 is a schematic explanatory diagram showing the basic principle of the second embodiment of the method of the present disclosure, illustrating the shape of the UD prepreg tape before shearing the deformed region between two boundaries. Fig. 4 is a schematic explanatory diagram showing the basic principle of the second embodiment of the method of the present disclosure, illustrating the shape of the UD prepreg tape after shearing the deformed region between the two boundaries. Fig. 5 is a schematic explanatory diagram showing the second embodiment of the method of the present disclosure, illustrating a straight UD prepreg tape that serves as a material for producing a curved UD prepreg tape. 1 is a schematic explanatory diagram showing a second embodiment of the method of the present disclosure, illustrating a state during which the operation of shearing the deformed region by rotating each of the two clips while moving the positions of each of the two boundary regions held by the two clips from each side of the two ends of the UD prepreg tape toward the center is repeated. 2 is a schematic explanatory diagram showing a second embodiment of the method of the present disclosure, illustrating a state after further repetition of the operation of shearing the deformed region by rotating each of the two clips while moving the positions of each of the two boundary regions held by the two clips from each side of the two ends of the UD prepreg tape toward the center.

[0015] Hereinafter, embodiments of the method of the present disclosure will be described in detail with reference to the drawings.

[0016] The method disclosed herein involves shearing a region between two boundaries that are symmetrically positioned relative to the center of a linear UD prepreg tape in the longitudinal direction of the UD prepreg tape using an appropriate means, thereby displacing regions closer to the ends of the UD prepreg tape than the two boundaries in opposite directions across the longitudinal direction of the UD prepreg tape. This operation is repeated while moving the positions of the two boundaries from the ends of the UD prepreg tape toward the center, thereby obtaining a UD prepreg tape that is curved into the desired shape.

[0017] First, the basic principle of the method of the present disclosure described above will be explained below with reference to FIG.

[0018] 1A to 1D are schematic explanatory diagrams showing the basic principle of bending a straight UD prepreg tape by the method of the present disclosure. Note that these figures are all top views of the UD prepreg tape.

[0019] 1A shows a linear UD prepreg tape T, which is a material for producing a curved UD prepreg tape. Although not shown, reinforcing fibers are oriented in the longitudinal direction Z within the UD prepreg tape T.

[0020] FIG. 1B shows a deformation region T of the UD prepreg tape T that is subject to shear deformation. Ｄ 1 shows the state before deformation.

[0021] Deformed area T Ｄ is the central portion T in the longitudinal direction Z of the UD prepreg tape T Ｃ The region has two boundary portions B at both ends, which are symmetrical with respect to the region B, and has a rectangular shape in the illustrated example.

[0022] Deformed area T Ｄ Prior to deformation, the UD prepreg tape T is heated by an appropriate means to a temperature at which the matrix resin contained in the tape T is easily deformed. Then, appropriate tools (not shown) are placed at the positions of the two boundaries B, and the deformation region T between the two boundaries B is deformed by the tools. Ｄis sheared in the longitudinal direction Z of the UD prepreg tape T.

[0023] FIG. 1C shows the deformation region T Ｄ The figure shows the state after deformation.

[0024] In the figure, the deformed portion T Ｄ is shear deformation (deformed part T Ｄ As a result of this rotation (see the arrows pointing in opposite directions shown above and below), both of the two boundary portions B are rotated clockwise.

[0025] Here, in the same figure, T Ｕ are the two ends T of the UD prepreg tape T. Ｅ and two boundary portions B. Ｕ is the deformation part T through the boundary part B. Ｄ Therefore, when the boundary portion B rotates clockwise as described above, the two non-deformed portions T Ｕ are rotationally displaced in opposite directions (vertical direction in the drawing) transverse to the longitudinal direction Z of the UD prepreg tape T. Specifically, the non-deformed region T on the left side in the drawing Ｕ is facing upward, the non-deformed part T on the right side Ｕ will be rotated downwards, respectively.

[0026] As a result, the UD prepreg tape T is bent in opposite directions at the two boundary portions B, forming an S-shape as a whole.

[0027] As described above, the deformation region T between the two boundaries B is formed by the tools arranged at the respective positions of the two boundaries B. Ｄ The operation of shearing the UD prepreg tape T in the longitudinal direction Z is performed by positioning the boundary B at the end T Ｅ Side to center T Ｃ By repeating this process while moving the tape to the desired shape, a UD prepreg tape CT curved in a desired shape can be obtained as shown in FIG. 1D.

[0028] A specific embodiment for obtaining a curved UD prepreg tape CT from a UD prepreg tape T by applying the basic principles described above will be described in detail below.

[0029] 2A to 2E are schematic explanatory diagrams showing a first embodiment of the method of the present disclosure, and all of these diagrams are top views of a UD prepreg tape.

[0030] In the figure, the UD prepreg tape is divided into two curved portions (two curved portions CP in FIG. 2E) having the same single curvature and opposite directions of the curvature. １ , CP ２ 10 illustrates an example in which the substrate is bent into a shape having a predetermined curvature (see FIG. 10).

[0031] In the first embodiment, a roller having a truncated cone shape is used as a tool for shearing the deformed portion of the UD prepreg tape.

[0032] 2A shows a linear UD prepreg tape T, which is a material for producing a curved UD prepreg tape. Although not shown, reinforcing fibers are oriented in the longitudinal direction Z within the UD prepreg tape T.

[0033] FIG. 2B shows two end portions T in the longitudinal direction Z of the UD prepreg tape T. Ｅ１ , T Ｅ２ Slightly more central than each of the Ｃ A truncated cone roller R is attached to the side. １ , R ２ 1, the first roller R is positioned so that the direction of each rotation axis is perpendicular to the longitudinal direction Z of the UD prepreg tape T. In this state, the first roller R １ The position where is arranged is the first boundary B １ and the second roller R ２ The position where is arranged is the second boundary B ２ and the region between them is the deformation region T Ｄ And, this deformation part T Ｄ is heated as described above prior to deformation.

[0034] In addition, two truncated cone rollers R１ , R ２ The first roller R has the same shape, but is arranged so that the directions of the diameters of the first roller R are opposite to each other. １ In the finally obtained curved UD prepreg tape CT, the first end T Ｅ１ A first curved portion CP formed on the side １ (see FIG. 2E) so that the diameter of the second roller R decreases from the outer periphery toward the inner periphery (i.e., from top to bottom in FIG. 2B). ２ In the finally obtained curved UD prepreg tape CT, the second end T Ｅ２ A second curved portion CP formed on the side ２ (see FIG. 2E) are arranged so that their diameters decrease from the outer periphery toward the inner periphery (i.e., from bottom to top in FIG. 2B).

[0035] In this state, the first and second rollers R １ , R ２ In the initial state, the roller R １ , R ２ Boundary B in contact with １ , B ２ When the rollers are rotated in a direction away from each other, the side edges of the UD prepreg tape T on the side with the larger diameter of each roller (the first roller R １ The second roller R ２ The side edge located at the bottom in the figure is relatively larger than the side edge located on the opposite side, and the central part T of the UD prepreg tape T Ｃ From each end T Ｅ１ , T Ｅ２ As a result, the deformation area T Ｄ is shear deformed.

[0036] At this time, the first boundary B １ and the first end T Ｅ１ A first non-deformed region T Ｕ１ is a first direction transverse to the longitudinal direction Z (first curved portion CP １ (i.e., downward in the drawing) at the second boundary B２ and the second end T Ｅ２ A second non-deformed region T Ｕ２ is a second direction transverse to the longitudinal direction Z (second curved portion CP ２ (i.e., upward in the drawing) (not shown; see FIG. 1C).

[0037] The above-described operations are performed on the first boundary B １ The position of the first end T Ｅ１ Side to center T Ｃ to the second boundary B ２ The position of the second end T Ｅ２ Side to center T Ｃ In other words, two rollers R １ , R ２ The respective positions of the Ｃ The deformation region T Ｄ The shear deformation of the specimen is symbolically shown through the displacement distribution in the longitudinal direction Z drawn at the center.)

[0038] And the boundary part B １ , B ２ The position of the UD prepreg tape T is the center T of the part to be curved. Ｃ When the end of the side is reached (see FIG. 2D), the repetition of the above-mentioned operation is completed, thereby finally obtaining the curved UD prepreg tape CT shown in FIG. 2E.

[0039] Here, the curved UD prepreg tape CT obtained by the above-mentioned method has a central portion T Ｃ Therefore, this has a point-symmetric shape with respect to the central part T Ｃ Here, the first curved portion CP is mainly cut at １ , second curved portion CP ２ In this way, by simultaneously producing curved UD prepreg tapes having point-symmetric shapes from both ends, it is possible to cancel out the accumulation of shear deformation.

[0040] The method described above can be said to be a method that can simultaneously produce two curved UD prepreg tapes to be laminated even when the curved UD tape shape is not point-symmetric.

[0041] Next, a modified example of the first embodiment of the method of the present disclosure will be described. While Figures 2A to 2E illustrate a case in which the shapes of the two curved portions of the finally obtained curved UD prepreg tape have the same single curvature in opposite directions, a case in which the shapes have multiple identical curvatures in opposite directions will be described below with reference to Figures 3A to 3F and Figures 4A to 4F.

[0042] 3A to 3F are schematic explanatory diagrams showing a first modified example of the first embodiment.

[0043] The figure illustrates an example in which a UD prepreg tape is bent into a point-symmetric shape having two curved portions (first and second curved portions), each of which has two different curvature portions (first and second curvature portions).

[0044] Specifically, as shown in FIG. 3F, the second curved portion CP ２ The second end T of the finally obtained curved UD prepreg tape CT is Ｅ２ In order, the radius of curvature r １ The first curvature portion CP ２１ and the radius of curvature r ２ The second curvature portion CP ２２ Similarly, the first curved portion CP １ The first end T of the curved UD prepreg tape CT to be finally obtained is Ｅ１ In order from the first curvature portion CP １１ (Although not shown, the radius of curvature is r １ ) and the second curvature portion CP １２ (Although not shown, the radius of curvature is r ２ ) are arranged adjacent to each other. In this example, the two radii of curvature are r １ <r ２ The following relationship shall be satisfied.

[0045] The first curved portion CP １In the first curvature portion CP １１ and the second curvature portion CP １２ The boundary with the first curvature boundary CP １Ｂ and the second curved portion CP ２ In the first curvature portion CP ２１ and the second curvature portion CP ２２ The boundary with the second curvature boundary CP ２Ｂ is.

[0046] In the first modified example, in order to change the curvature of the two curved portions during the formation of the curved portions, a means is adopted in which the diameter of the portion in contact with the surface of the UD prepreg tape is changed by shifting the truncated cone-shaped roller in the direction of its rotation axis.

[0047] 3A shows a linear UD prepreg tape T, which is a material for producing a curved UD prepreg tape. Although not shown, the reinforcing fibers are oriented in the longitudinal direction Z within the UD prepreg tape T.

[0048] FIG. 3B shows two end portions T in the longitudinal direction Z of the UD prepreg tape T. Ｅ１ , T Ｅ２ Slightly more central than each of the Ｃ A truncated cone roller R is attached to the side. １ , R ２ 1 and 2, the first roller R is positioned so that the direction of each rotation axis is perpendicular to the longitudinal direction Z of the UD prepreg tape T. That is, in this state, the first roller R １ The position where is arranged is the first boundary B １ and the second roller R ２ The position where is arranged is the second boundary B ２ and the region between them is the deformation region T Ｄ And, this deformation part T Ｄ is heated as described above prior to deformation.

[0049] In addition, two truncated cone rollers R １ , R ２ The first roller R has the same shape, but is arranged so that the directions of the diameters of the first roller R along the rotation axis are opposite to each other.１ In the finally obtained curved UD prepreg tape CT, the first end T Ｅ１ A first curved portion CP formed on the side １ (see FIG. 3F) so that the diameter of the second roller R decreases from the outer periphery toward the inner periphery (i.e., from top to bottom in FIG. 3B). ２ In the finally obtained curved UD prepreg tape CT, the second end T Ｅ２ A second curved portion CP formed on the side ２ (see FIG. 3F) are arranged so that their diameters decrease from the outer periphery toward the inner periphery (i.e., from bottom to top in FIG. 3B).

[0050] In this state, the first and second rollers R １ , R ２ In the initial state, the roller R １ , R ２ Boundary B in contact with １ , B ２ When the rollers are rotated in a direction away from each other, the side edges of the UD prepreg tape T on the side with the larger diameter of each roller (the first roller R １ The second roller R ２ The side edge located at the bottom in the figure is relatively larger than the side edge located on the opposite side, and the central part T of the UD prepreg tape T Ｃ From each end T Ｅ１ , T Ｅ２ As a result, the deformation area T Ｄ is shear deformed.

[0051] At this time, the first boundary B １ and the first end T Ｅ１ A first non-deformed region T Ｕ１ is a first direction transverse to the longitudinal direction Z (first curved portion CP １ (i.e., downward in the drawing) at the second boundary B ２ and the second end T Ｅ２ A second non-deformed region T Ｕ２is a second direction transverse to the longitudinal direction Z (second curved portion CP ２ (i.e., upward in the drawing) (not shown; see FIG. 1C).

[0052] The above-described operations are performed on the first boundary B １ The position of the first end T Ｅ１ Side to center T Ｃ to the second boundary B ２ The position of the second end T Ｅ２ Side to center T Ｃ In other words, two rollers R １ , R ２ The respective positions of the Ｃ The deformation region T Ｄ (The shear deformation of the specimen is symbolically shown by the displacement distribution in the longitudinal direction Z drawn at the center of the specimen.)

[0053] However, this repetition is performed on the first roller R １ is the first curved portion CP １ The first curvature boundary CP at １Ｂ and the second roller R ２ is the second curved portion CP ２ The second curvature boundary CP at ２Ｂ The process is temporarily stopped when the first bending portion CP １ The first curvature portion CP １１ and the second curved portion CP ２ The first curvature portion CP ２１ is formed (see FIG. 3C).

[0054] At this point, the first roller R １ and the second roller R ２ are shifted by the same distance in the direction of their respective rotation axes, specifically in the direction of decreasing diameter.

[0055] Here, the first roller R before shifting １ is the diameter of Ｓ１ From d Ｓ２The roller R is in contact with the surface of the UD prepreg tape T. ２ is the diameter of Ｓ１ From d Ｓ２ The area up to the point where the UD prepreg tape T is in contact with the surface of the UD prepreg tape T is Ｓ１ <d Ｓ２ (See FIG. 3C).

[0056] On the other hand, the first roller R after shifting by the same distance in the direction of each rotation axis, specifically in the direction of reducing the diameter, １ is the diameter of Ｌ１ From d Ｌ２ The roller R is in contact with the surface of the UD prepreg tape T. ２ is the diameter of Ｌ１ From d Ｌ２ The area up to the point where the UD prepreg tape T is in contact with the surface of the UD prepreg tape T is Ｌ１ <d Ｌ２ (See FIG. 3D).

[0057] Furthermore, the four diameters mentioned above are at least d Ｓ１ <d Ｌ１ and d Ｓ２ <d Ｌ２ (See FIGS. 3C and 3D).

[0058] Here, the above-mentioned diameter is determined based on the geometric characteristics of the truncated cone, d Ｌ２ / d Ｌ１ <d Ｓ２ / d Ｓ１ This satisfies the relationship of the roller R before shifting. １ , R ２ Deformation area T Ｄ Boundary B due to shear deformation １ , B ２ The rotational displacement of the roller R after shifting １ , R ２ Deformation area T Ｄ Boundary B due to shear deformation １ , B ２ In other words, the rotational displacement of the roller R before shifting is larger than that of the roller R before shifting. １ , R ２The first curvature portion CP formed by １１ The curvature of the roller R after shifting １ , R ２ The second curvature portion CP formed by １２ Therefore, the curvature of the first curvature portion CP １１ Radius of curvature r １ The second curvature portion CP １２ Radius of curvature r ２ is smaller (as mentioned above, r １ <r ２ ) means

[0059] As described above, the two rollers R １ , R ２ After shifting each of the first boundary B １ The position of the first end T Ｅ１ Side to center T Ｃ to the second boundary B ２ The position of the second end T Ｅ２ Side to center T Ｃ In other words, two rollers R １ , R ２ The respective positions of the Ｃ , and the same operation as before the shift is repeated while moving the first curved portion CP at the same speed. １ The second curvature portion CP １２ and the second curved portion CP ２ The second curvature portion CP ２２ is formed (see FIG. 3E).

[0060] And the boundary part B １ , B ２ The position of the UD prepreg tape T is the center T of the part to be curved. Ｃ When the end of the side is reached (see FIG. 3E), the repetition of the above-mentioned operation is completed, thereby finally obtaining the curved UD prepreg tape CT shown in FIG. 3F.

[0061] In the above, the first curvature portion CP １１ Radius of curvature r １ The second curvature portion CP １２ Radius of curvature r ２ smaller than (r１ <r ２ ) case has been described, but the first curvature portion CP １１ Radius of curvature r １ The second curvature portion CP １２ Radius of curvature r ２ greater than (r １ >r ２ ) in the case where the first roller R １ and the second roller R ２ will be shifted by the same distance in the opposite direction to the direction of the reduction in diameter along the axis of rotation.

[0062] 4A to 4F are schematic explanatory diagrams showing a second modified example of the first embodiment.

[0063] The figure illustrates an example in which a UD prepreg tape is bent into a point-symmetric shape having two curved portions (first and second curved portions), each of which has two different curvature portions (first and second curvature portions).

[0064] Specifically, as shown in FIG. 4F, the second curved portion CP ２ The second end T of the finally obtained curved UD prepreg tape CT is Ｅ２ , the first curvature portion CP having a curvature radius r′. ２１ and a second curvature portion CP having a curvature radius r. ２２ Similarly, the first curved portion CP １ is the first end T of the finally obtained curved UD prepreg tape CT. Ｅ１ In order from the first curvature portion CP １１ (Although not shown, the radius of curvature is r') and the second curvature portion CP １２ (Although not shown, the radius of curvature is r) are arranged adjacent to each other. In this example, the two radii of curvature satisfy the relationship r<r'.

[0065] However, the second curved portion CP ２ The first curvature portion CP ２１ is the second end T Ｅ２ In order, the arc-shaped portion CP having a curvature radius r ２１Ｃ and the linear portion CP ２１ＳThe first curved portion CP is a portion that can be approximately regarded as having a curvature radius r′ as a whole. １ The first curvature portion CP １１ is the first end T Ｅ１ In order, the arc-shaped portion CP １１Ｃ (not shown, but the radius of curvature is r) and the linear portion CP １１Ｓ and the entire portion can be approximately regarded as having a radius of curvature r'.

[0066] In addition, the second curved portion CP ２ In the first curvature portion CP ２１ The arc-shaped portion CP in ２１Ｃ and the linear portion CP ２１Ｓ The boundary with the second shape boundary CP ２１Ｂ and the first curvature portion CP ２１ and the second curvature portion CP ２２ The boundary with the second curvature boundary CP ２Ｂ Similarly, the first curved portion CP １ In the first curvature portion CP １１ The arc-shaped portion CP in １１Ｃ and the linear portion CP １１Ｓ The boundary with the first shape boundary CP １１Ｂ and the first curvature portion CP １１ and the second curvature portion CP １２ The boundary with the first curvature boundary CP １Ｂ is.

[0067] In the second modified example, the means for changing the curvature of the two curved portions during the formation of the two curved portions is a combination of a process of bringing a truncated cone-shaped roller into contact with the surface of the UD prepreg tape and shearing the deformed portion, and a process of moving the truncated cone-shaped roller without contacting the surface of the UD prepreg tape.

[0068] 4A shows a linear UD prepreg tape T, which is a material for producing a curved UD prepreg tape. Although not shown, the reinforcing fibers are oriented in the longitudinal direction Z within the UD prepreg tape T.

[0069] FIG. 4B shows two end portions T in the longitudinal direction Z of the UD prepreg tape T.Ｅ１ , T Ｅ２ Slightly more central than each of the Ｃ A truncated cone roller R is attached to the side. １ , R ２ 1 and 2, the first roller R is positioned so that the direction of each rotation axis is perpendicular to the longitudinal direction Z of the UD prepreg tape T. That is, in this state, the first roller R １ The position where is arranged is the first boundary B １ and the second roller R ２ The position where is arranged is the second boundary B ２ and the region between them is the deformation region T Ｄ And, this deformation part T Ｄ is heated as described above prior to deformation.

[0070] In addition, two truncated cone rollers R １ , R ２ The first roller R has the same shape, but is arranged so that the directions of the diameters of the first roller R are opposite to each other. １ In the finally obtained curved UD prepreg tape CT, the first end T Ｅ１ A first curved portion CP formed on the side １ (see FIG. 4F) so that the diameter of the second roller R decreases from the outer periphery toward the inner periphery (i.e., from top to bottom in FIG. 4B). ２ In the finally obtained curved UD prepreg tape CT, the second end T Ｅ２ A second curved portion CP formed on the side ２ (see FIG. 4F) are arranged so that their diameters decrease from the outer periphery toward the inner periphery (i.e., from bottom to top in FIG. 4B).

[0071] In this state, the first and second rollers R １ , R ２ In the initial state, the roller R １ , R ２ Boundary B in contact with １ , B ２When the rollers are rotated in a direction away from each other, the side edges of the UD prepreg tape T on the side with the larger diameter of each roller (the first roller R １ The second roller R ２ The side edge located at the bottom in the figure is relatively larger than the side edge located on the opposite side, and the central part T of the UD prepreg tape T Ｃ From each end T Ｅ１ , T Ｅ２ As a result, the deformation area T Ｄ is shear deformed.

[0072] At this time, the first boundary B １ and the first end T Ｅ１ A first non-deformed region T Ｕ１ is a first direction transverse to the longitudinal direction Z (first curved portion CP １ (i.e., downward in the drawing) at the second boundary B ２ and the second end T Ｅ２ A second non-deformed region T Ｕ２ is a second direction transverse to the longitudinal direction Z (second curved portion CP ２ (i.e., upward in the drawing) (not shown; see FIG. 1C).

[0073] The above-described operations are performed on the first boundary B １ The position of the first end T Ｅ１ Side to center T Ｃ to the second boundary B ２ The position of the second end T Ｅ２ Side to center T Ｃ In other words, two rollers R １ , R ２ The respective positions of the Ｃ The deformation region T Ｄ (The shear deformation of the specimen is symbolically shown by the displacement distribution in the longitudinal direction Z drawn at the center of the specimen.)

[0074] However, this repetition is performed on the first roller R １is the first curved portion CP １ The first shape boundary CP in １１Ｂ and the second roller R ２ is the second curved portion CP ２ The second shape boundary CP ２１Ｂ The process is temporarily stopped when the first bending portion CP １ The first curvature portion CP １１ The arc-shaped portion CP constituting the １１Ｃ and the second curved portion CP ２ The first curvature portion CP ２１ The arc-shaped portion CP constituting the １１Ｃ and are formed (see FIG. 4C).

[0075] After the above-mentioned process, the first roller R １ is the first curved portion CP １ The first curvature boundary CP at １Ｂ The second roller R ２ is the second curved portion CP ２ The second curvature boundary CP at ２Ｂ , respectively (see FIG. 4D).

[0076] That is, in the UD prepreg tape T, the first shape boundary CP １１Ｂ and the first curvature boundary CP １Ｂ and the second shape boundary CP ２１Ｂ and the second curvature boundary CP ２Ｂ In the portion between the positions corresponding to the first roller R １ and the second roller R ２ As a result, these portions maintain a linear shape, and in the finally obtained curved UD prepreg tape CT, the first curved portion CP １ The first curvature portion CP １１ The linear portion CP constituting the １１Ｓ , and the second curved portion CP ２ The first curvature portion CP ２１ The linear portion CP constituting the ２１Ｓ This becomes:

[0077] Then, the first boundary B １ The position of the first curved portion CP １ The first curvature boundary CP at １Ｂ From the position corresponding to the center T Ｃ to the second boundary B ２ The position of the second curved portion CP ２ The second curvature boundary CP at ２Ｂ From the position corresponding to the center T Ｃ In other words, two rollers R １ , R ２ Each of the central part T Ｃ The same operation is repeated while moving the first curved portion CP at the same speed. １ The second curvature portion CP １２ and the second curved portion CP ２ The second curvature portion CP ２２ is formed (see FIG. 4E).

[0078] And the boundary part B １ , B ２ The position of the UD prepreg tape T is the center T of the part to be curved. Ｃ When the end of the side is reached (see FIG. 4E), the repetition of the above-mentioned operation is completed, thereby finally obtaining the curved UD prepreg tape CT shown in FIG. 4F.

[0079] Next, a second embodiment of the method of the present disclosure will be described.

[0080] In the second embodiment, when the deformed portion of the UD prepreg tape is shear-deformed, the two boundary portions are held by clips.

[0081] That is, in a second embodiment of the method of the present disclosure, two boundary portions located symmetrically with respect to the center portion in the longitudinal direction of a linear UD prepreg tape are each held with a clip, and each of these two clips is rotated in the same direction by an angle that is bisected by a line extending perpendicular to the longitudinal direction of the UD prepreg tape, thereby shearing the deformation portion between them, and thereby displacing portions located closer to the ends of the UD prepreg tape than the two boundary portions in opposite directions transverse to the longitudinal direction of the UD prepreg tape. By repeating this operation while moving the positions of the two boundary portions from the ends of the UD prepreg tape to the center, a UD prepreg tape curved into a desired shape is obtained.

[0082] First, the basic principle of the second embodiment of the method of the present disclosure described above will be explained below with reference to FIGS. 5A-5B.

[0083] 5A and 5B are schematic explanatory diagrams showing the shape of the UD prepreg tape before and after the two boundary portions are held by clips and the portion between them is shear-deformed, with Fig. 5A showing the shape before deformation and Fig. 5B showing the shape after deformation. Note that these figures show the state of deformation around one of the two boundary portions.

[0084] In Fig. 5A, B is one of two boundary portions arranged at a position symmetrical with respect to the center portion (not shown) in the longitudinal direction Z of the UD prepreg tape T. The two boundary portions B, including the one not shown, are the deformation portion T that is subject to shear deformation. Ｄ These are both ends in the longitudinal direction Z of the UD prepreg tape T.

[0085] The boundary portion B is held by clips CL (more specifically, the boundary portion B is sandwiched by clips CL from both sides in the thickness direction of the UD prepreg tape T).

[0086] At this time, the clip CL is inclined at an angle θ with respect to a straight line N extending in a direction perpendicular to the longitudinal direction Z of the UD prepreg tape T. More precisely, the clip CL is inclined at an angle θ with respect to the deformation region TＤ The deformation portion T is tilted backward (i.e., clockwise) by the above-mentioned angle with respect to the rotational movement (counterclockwise in the figure) for shearing deformation. Ｄ will have the shape of a parallelogram.

[0087] FIG. 5B shows the state in which the clip CL is rotated counterclockwise by an angle 2θ from this state.

[0088] As the clip CL rotates counterclockwise, the boundary B held by the clip CL rotates by an angle 2θ and is displaced to the left in the drawing. As a result, a deformed portion T Ｄ will be shear deformed as a whole (i.e., the region between the illustrated boundary B and the other boundary not shown as a whole).

[0089] 5A and 5B, the rotation angle 2θ of the clip CL is an angle bisected by a line N extending in a direction perpendicular to the longitudinal direction Z of the UD prepreg tape T. By selecting the angle in this manner, the UD prepreg tape T can be shear deformed without changing its width or thickness.

[0090] Here, in FIGS. 5A and 5B, T Ｕ is the end T of the UD prepreg tape T Ｅ and the boundary B. Ｕ is the deformation part T through the boundary part B. Ｄ Therefore, when the boundary portion B rotates counterclockwise as described above, the non-deformed portion T Ｕ will be rotationally displaced in a direction transverse to the longitudinal direction Z of the UD prepreg tape T (the up-down direction in the figure), specifically downward (it goes without saying that the other non-deformed portion, not shown in the figure, will be rotationally displaced upward in the figure).

[0091] As a result, the UD prepreg tape T is bent in opposite directions at the two boundary portions B, forming an S-shape as a whole.

[0092] As described above, the two boundary portions B are rotated by the clips CL to form the deformation portions T Ｄ The operation of shearing the boundary B is performed by moving the boundary B to the edge T. Ｅ By repeating this process while moving from the side to the center, a UD prepreg tape curved to the desired shape can be obtained.

[0093] In Figures 5A and 5B, the clip CL is rotated around a point located outside the UD prepreg tape T, but the center of rotation of the clip CL may be located at its center (i.e., the center in the width direction perpendicular to the longitudinal direction Z of the UD prepreg tape T).

[0094] A specific embodiment for obtaining a curved UD prepreg tape CT from a UD prepreg tape T by applying the basic principles described above will be described in detail below.

[0095] 6A to 6C are schematic explanatory diagrams showing a second embodiment of the method of the present disclosure, each of which is a top view of a UD prepreg tape.

[0096] In the figure, an example is shown in which a UD prepreg tape is bent into a shape having two curved portions with the same single curvature but with the directions of the curvature opposite to each other.

[0097] 6A shows a linear UD prepreg tape T, which is a material for producing a curved UD prepreg tape. Although not shown, the reinforcing fibers are oriented in the longitudinal direction Z within the UD prepreg tape T.

[0098] FIG. 6B shows the state in which the entire UD prepreg tape T is heated and then two clips CL are attached. １ , C.L. ２ Two boundaries B held by each of １ , B ２ The positions of the two ends T of the UD prepreg tape T are Ｅ１ , T Ｅ２ While moving from each side to the center, １ , C.L.２ By rotating each of the above, the deformation part T Ｄ 5A and 5B) is repeated. １ ', H ２ ' indicates the boundary corresponding to an operation that has already been performed.

[0099] FIG. 6C shows the situation after a further iteration of the above operations.

[0100] In this way, a curved UD prepreg tape CT is finally obtained.

[0101] According to the method described above, the UD prepreg tape is curved only through in-plane shear deformation of the UD prepreg tape, so the reinforcing fibers in the prepreg do not undulate in-plane or out-of-plane. This eliminates defects caused by undulation. Furthermore, since a wide (i.e., thick) UD prepreg tape can be used, costs can be reduced by shortening the time required for lamination compared to conventional techniques that required the use of a narrow (i.e., thin) UD prepreg tape. Furthermore, a wide UD prepreg tape has a lower unit price per weight than a narrow UD prepreg tape, which also contributes to cost reductions.

[0102] (Aspects of the Present Disclosure) In a manufacturing method for a curved UD prepreg tape according to a first aspect of the present disclosure, a deformed region between two boundary regions that are symmetrically positioned with respect to a center portion in the longitudinal direction of a linear UD prepreg tape is shear-deformed in the longitudinal direction of the UD prepreg tape, thereby displacing a non-deformed region that is closer to the end portion of the UD prepreg tape than the two boundary regions in mutually opposite directions transverse to the longitudinal direction of the UD prepreg tape. This operation is repeated while moving the positions of the two boundary regions from the end portion side to the central portion of the UD prepreg tape.

[0103] In the manufacturing method of a curved UD prepreg tape according to the second aspect of the present disclosure, two rollers each having a truncated cone shape are arranged at the two boundary portions so that the direction of their rotation axes is perpendicular to the longitudinal direction of the UD prepreg tape, and the directions of reduction in the diameter of the two rollers along the rotation axes are opposite to each other. The two rollers are rotated while in contact with the surface of the UD prepreg tape to move each of the two boundary portions in directions away from the central portion, thereby shearing the deformation region.

[0104] In the manufacturing method of a curved UD prepreg tape according to the third aspect of the present disclosure, the curved UD prepreg tape has two curved portions that are positioned symmetrically with respect to the central portion, and each of the two curved portions has a plurality of curvature portions with different radii of curvature arranged adjacent to each other, and when the positions of the two boundary portions move toward the central portion and reach the boundary between the adjacent curvature portions, the operation is temporarily interrupted, and the two rollers are shifted by the same distance in the direction of reducing the diameter along the rotation axis or in the opposite direction.

[0105] In the manufacturing method of a curved UD prepreg tape according to the fourth aspect of the present disclosure, the curved UD prepreg tape has two curved portions that are positioned symmetrically with respect to the central portion, and each of the two curved portions has a plurality of curved portions with different radii of curvature arranged adjacent to one another, and at least one of the plurality of curved portions is made up of an arc-shaped portion and a straight portion and is a portion that is considered to have an approximate curvature as a whole, and when the positions of the two boundary portions move toward the central portion, the roller does not come into contact with the surface of the UD prepreg tape when moving over the portion corresponding to the straight portion.

[0106] In the manufacturing method of the curved UD prepreg tape of the fifth aspect of the present disclosure, the two boundary portions are each held by two clips, and each of the two clips rotates the two boundary portions in the same direction by an angle that is bisected by a line extending perpendicular to the longitudinal direction, thereby causing the deformation site to shear.

[0107] CP １ , CP ２ Curved section CT Curved UD prepreg tape B, B １ , B ２ Boundary R １ , R ２ Roller T Linear UD prepreg tape T Ｃ　 Center of UD prepreg tape T Ｄ　 Deformed area of ​​UD prepreg tape T Ｅ , T Ｅ１ , T Ｅ２ End of UD prepreg tape T Ｕ , T Ｕ１ , T Ｕ２ Non-deformed portion of UD prepreg tape Z Longitudinal direction of UD prepreg tape

Claims

1. A method for manufacturing a curved UD prepreg tape, in which a deformed area between two boundaries that are located symmetrically with respect to a center in the longitudinal direction of a straight UD prepreg tape is shear-deformed in the longitudinal direction of the UD prepreg tape, thereby displacing a non-deformed area located closer to the end of the UD prepreg tape than the two boundaries in mutually opposite directions transverse to the longitudinal direction of the UD prepreg tape, while the positions of the two boundaries are moved from the end sides to the central part of the UD prepreg tape.

2. The method according to claim 1, wherein two truncated cone-shaped rollers are arranged at the two boundaries with the direction of their rotation axes perpendicular to the longitudinal direction of the UD prepreg tape, the directions of reduction in diameter along the rotation axes of the two rollers are opposite to each other, and the two rollers rotate while in contact with the surface of the UD prepreg tape to move each of the two boundaries in a direction away from the central portion, thereby shearing the deformation site.

3. The method according to claim 2, wherein the curved UD prepreg tape has two curved portions that are symmetrically positioned with respect to the central portion, and each of the two curved portions has a plurality of curvature portions with different radii of curvature arranged adjacent to each other, and when the positions of each of the two boundary portions move toward the central portion and reach the boundary between the adjacent curvature portions, the operation is temporarily interrupted, and the two rollers are shifted by the same distance in the direction of reducing the diameter along the rotation axis or in the opposite direction.

4. The method according to claim 2, wherein the curved UD prepreg tape has two curved portions positioned symmetrically with respect to the central portion, each of the two curved portions has a plurality of curved portions with different radii of curvature arranged adjacent to each other, at least one of the plurality of curved portions is a portion that consists of an arc-shaped portion and a straight portion and is considered to have an approximate curvature as a whole, and when the positions of each of the two boundary portions move toward the central portion, the roller does not contact the surface of the UD prepreg tape when moving over a portion corresponding to the straight portion.

5. The method according to claim 1, wherein the two boundary portions are respectively held by two clips, and the deformation portion is shear deformed by rotating the two boundary portions in the same direction by an angle bisected by a line extending perpendicular to the longitudinal direction of the two clips.

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