Method for manufacturing a structure and structure

Abstract

The present invention provides a method for manufacturing a structure having high shape accuracy and strength at low cost and a structure. The method for manufacturing a structure includes: a first step of winding a plurality of sheets containing reinforcing fibers and uncured thermosetting resin around a mandrel MD to form a layered body LM in a cylindrical shape; a second step of pressing the entire circumference of the layered body LM with a tape TP; a third step of heating the layered body LM until a state before the thermosetting resin is completely cured; a fourth step of pulling out the mandrel MD from the layered body LM; a fifth step of disposing the layered body LM, on which the tape TP is wound, in a molding die UD, LD, and pressing and heating the layered body LM until the thermosetting resin is completely cured; and a sixth step of taking out the layered body LM from the molding die UD, LD, and peeling off the tape TP.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for manufacturing a structure and a structure. BACKGROUND

[0002] From the viewpoint of weight reduction of a component, attempts have been made to replace a metal structure with, for example, a structure made of FRP (Fiber Reinforced Plastics) obtained by reinforcing a carbon fiber with a resin. Here, as a structure made of FRP, a hollow cylindrical member that has been used for a bicycle frame and the like is known.

[0003] However, a frame of a bicycle is originally a product obtained by joining metal pipes, and thus, in addition to problems of a joint portion and the like, it is relatively easy to replace it with a hollow cylindrical member made of FRP. On the other hand, a structure for a vehicle and the like has a problem in that it is difficult to directly use a hollow cylindrical member because of a limited installation space. Thus, in order to be widely used in the form of a structure, there is a demand to form a structure made of FRP in a plate shape or a non-circular hollow cross-sectional shape (for example, a square tube shape).

[0004] As one scheme of forming a structure made of FRP in a plate shape, there is a method of laminating a plurality of prepreg sheets on a molding die and completely curing them. The prepreg refers to a sheet-shaped reinforced plastic molding product in which a thermosetting resin such as an epoxy resin is uniformly impregnated into a reinforcing fiber, and is heated or dried to be in a semi-cured state.

[0005] However, a structure made of FRP formed in this way has a problem in that it is easy to generate a strain during curing, and a flat plate shape with good precision cannot be obtained.

[0006] Further, when a torsional deformation is repeatedly applied to both ends of a structure made of FRP formed in this way in a plate shape, a relative movement occurs between a sheet on the upper surface side and a sheet on the lower surface side. Thus, at both edges in the central width direction of the structure, peeling of the sheets and fiber peeling are likely to occur, and there is a problem in that the strength is reduced.

[0007] On the other hand, as one scheme of forming a structure made of FRP in a non-circular hollow cross-sectional shape, there is a method of disposing a flexible hollow core having a prepreg or the like laminated on the outer periphery in a molding die, inflating the hollow core by pressurization and heating, thereby conforming the outer surface of the prepreg to the die and molding. However, when the wall thickness of the prepreg changes during the pressurization / heating process at the time of molding by this method, there is a risk of wrinkles, voids, and resin concentration due to the reinforcing fiber failing to follow the shape change conforming to the die. Thus, there is a problem in that the product quality and the product strength of the structure made of FRP are reduced.

[0008] On the other hand, as a technique for forming an FRP structure having a non-circular hollow cross-sectional shape, the technique disclosed in Patent Literature 1 is known. According to the technique disclosed in Patent Literature 1, by arranging a hollow core having a reinforcing fiber base material arranged on the outer periphery in a mold cavity of a molding die, and after closing the molding die, injecting resin into the molding die while pressurizing the core, it is possible to mold an FRP hollow structure.

[0009] Prior Art Documents

[0010] Patent Literature

[0011] Patent Literature 1: Japanese Patent Application Laid-Open (kokai) No. 2006-159457 SUMMARY

[0012] Problem to be solved by the invention

[0013] According to the technique of Patent Literature 1, it is said that by injecting resin into the molding die while pressurizing the hollow core arranged in the molding die, it is possible to avoid the occurrence of wrinkles, voids, and the like in the FRP hollow structure. However, in this technique, a large device such as a resin flow path for injecting resin into the molding die is required, and there is a problem of cost consumption.

[0014] Thus, an object of the present application is to provide a method for manufacturing a structure having high shape accuracy and strength at low cost, and a structure.

[0015] Solution for solving the problem

[0016] To achieve the above object, the method for manufacturing a structure of the present application has the following steps:

[0017] a first step of winding a plurality of sheets each containing a reinforcing fiber and an uncured thermosetting resin and / or a tape around the periphery of a mandrel to form a cylindrical laminated body;

[0018] a second step of pressing a tape or film around the entire periphery of the laminated body;

[0019] a third step of heating the laminated body until the thermosetting resin is completely cured;

[0020] a fourth step of pulling out the mandrel from the laminated body; and

[0021] a fifth step of arranging the laminated body having the tape or film wound thereon in a molding die and pressurizing, and heating the laminated body until the thermosetting resin is completely cured.

[0022] The structure of the present application is formed of a thermosetting resin impregnated into a reinforcing fiber, and has a first plane and a second plane on an outer surface, in a cross section orthogonal to an axis of the aforementioned structure, a normal line extending outward from the aforementioned first plane and a normal line extending outward from the aforementioned second plane are directed toward different directions, the intersection of the aforementioned first plane and the aforementioned second plane has a curved surface with a fixed curvature or a gradually changing curvature, and the aforementioned reinforcing fiber is continuous without being broken through the aforementioned intersection.

[0023] The structure of the present application is formed of a thermosetting resin impregnated into a reinforcing fiber, has at least two plane portions bent at an intersection, and is formed in a polygonal shape or a flat plate shape,

[0024] The aforementioned intersection has a curved outer surface,

[0025] The aforementioned reinforcing fiber extends from one of the aforementioned plane portions to the other plane portion through the aforementioned intersection.

[0026] The structure of the present application is formed by the following operations:

[0027] A plurality of sheets and / or tapes containing a reinforcing fiber and an uncured thermosetting resin are wound around a core bar to form a cylindrical laminated body,

[0028] The entire circumference of the aforementioned laminated body is pressed with a tape or a film,

[0029] The aforementioned laminated body is heated until a state before the aforementioned thermosetting resin is completely cured,

[0030] The aforementioned core bar is pulled out from the aforementioned laminated body,

[0031] The aforementioned laminated body wound with the aforementioned tape or film is arranged in a molding die and is pressed, and the aforementioned laminated body is heated until the aforementioned thermosetting resin is completely cured.

[0032] Note that the structure of the present application is difficult to directly define due to its structure or characteristics, and therefore, the structure itself is defined according to the manufacturing method of the structure.

[0033] Effects of the invention

[0034] According to the present application, a manufacturing method of a structure and a structure having high shape accuracy and strength despite low cost can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a view showing the first step of the manufacturing method of the structure described in the present embodiment, and shows a prepreg and a core bar in plan view.

[0036] Figure 2Fig. 2 is a view showing a second step of the production method of the structure according to the present embodiment.

[0037] Figure 3 Fig. 3 is a view showing a third step of the production method of the structure according to the present embodiment.

[0038] Figure 4 Fig. 4 is a view showing an example of a DSC curve of the uncured thermosetting resin, in which the vertical axis represents heat flow and the horizontal axis represents temperature.

[0039] Figure 5 Fig. 5 is a view showing an example of a DSC curve of the completely cured thermosetting resin, in which the vertical axis represents heat flow and the horizontal axis represents temperature.

[0040] Figure 6 Fig. 6 is a view showing a fourth step of the production method of the structure according to the present embodiment, showing a state in which the mandrel is pulled out of the laminate.

[0041] Figure 7 Fig. 7 is a view showing a part of a fifth step of the production method of the structure according to the present embodiment, showing a state in which the rubber body is inserted into the laminate.

[0042] Figure 8 Fig. 8 is a cross-sectional view showing a part of the fifth step of the production method of the structure according to the present embodiment, showing a state before the mold is closed, as viewed in the axial direction of the laminate.

[0043] Figure 9 Fig. 9 is a cross-sectional view showing a part of the fifth step of the production method of the structure according to the present embodiment, showing a state after the mold is closed and heated.

[0044] Figure 10 Fig. 10 is a perspective view of the structure produced by the production method according to the present embodiment.

[0045] Figure 11 Fig. 11 is a cross-sectional view showing a state in which the mounting member is mounted to the structure.

[0046] Figure 12 Fig. 12 is a perspective view of the structure to which the mounting member is mounted, showing a part of the laminate in perspective.

[0047] Figure 13 Fig. 13 is a cross-sectional view showing a part of a fifth step of the production method of the structure according to another embodiment, showing a state before the mold is closed, as viewed in the axial direction of the laminate.

[0048] Figure 14 Fig. 14 is a cross-sectional view showing a part of the fifth step of the production method of the structure according to another embodiment, showing a state after the mold is closed and heated.

[0049] Figure 15 is a perspective view of a structure manufactured using the manufacturing method described in another embodiment.

[0050] Figure 16 is a plan view of a structure manufactured using the manufacturing method described in another embodiment, shown together with a reinforcing fiber.

[0051] Figure 17 is a cross-sectional view of a structure of a modification example.

[0052] Figure 18 is a cross-sectional view of a structure of a modification example.

[0053] Figure 19 is a cross-sectional view of a structure of another modification example.

[0054] Figure 20 is a perspective view of a structure of another modification example.

[0055] Reference Signs List

[0056] PS1 to PS6 prepreg sheets

[0057] MD core bar

[0058] TP tape

[0059] OV oven

[0060] RD rotary drive body

[0061] GM rubber body

[0062] UD upper mold

[0063] LD lower mold

[0064] AT attachment member

[0065] ST1, ST2, ST3, ST4 structures DETAILED DESCRIPTION

[0066] Hereinafter, embodiments described in the present application will be explained with reference to the drawings.

[0067] Note that, in the present specification, "reinforcing fiber" is preferably an organic fiber represented by carbon fiber, glass fiber, aramid fiber, silicon carbide fiber, metal fiber, and the like. Further, "thermosetting resin" is preferably an epoxy resin, a polyester resin, a vinyl ester resin, a phenol resin, a urethane resin, a polyimide resin, and the like.

[0068] The "cylindrical laminate" can be formed by winding a sheet of prepreg prepared by impregnating a thermosetting resin into a reinforcing fiber and heating or drying using a sheet winding method, or by winding a tape of prepreg using a tape winding method.

[0069] Alternatively, the cylindrical laminate can also be formed by winding using a filament winding method in which a resin is impregnated into a roving fiber while being wound. Of these, the sheet winding method and the tape winding method are more preferable because the ratio of the resin to the reinforcing fiber can be controlled and stable prepreg can be used.

[0070] As the prepreg, TORAYCA (registered trademark) manufactured by Toray Industries, Inc. can be suitably used, for example.

[0071] The material of the "mandrel" can be any of metal, resin, ceramic, etc., and from the viewpoint of cost and durability, a metal is preferably used. Furthermore, the shape of the mandrel is preferably a solid cylindrical shape or a hollow cylindrical shape, and can be a shape that can be divided rather than a single shape.

[0072] In this specification, the "tape or film" refers to a thin-walled member regardless of the raw material. Of these, a tape is preferably used from the viewpoint of ease of use. The tape can be any of a resin and a metal, and a resin tape that is good in workability is preferably used. Furthermore, when a resin tape is used, it can be any of polypropylene, polyethylene, polyester, glass paper, Teflon (registered trademark), polyimide, etc., and from the viewpoint of good balance of the properties of the tape, polypropylene and polyester are preferably used.

[0073] [First Embodiment]

[0074] A method for manufacturing the structure described in the first embodiment will be described. Figure 1 is a view schematically showing the first step. As shown in Figure 1 , a mandrel MD and various prepreg sheets PS1 to PS6 are prepared.

[0075] The outer diameter of the mandrel MD is set to be slightly smaller than the outer circumference of the structure to be finally formed, in consideration of the thickness of the laminate wound to the outside. That is, it is desirable that the outer diameter in the state in which a plurality of prepreg sheets are wound to the mandrel MD substantially coincides with the design value of the outer circumference of the structure to be finally formed.

[0076] The prepreg sheets PS1 to PS6 used here are sheets obtained by impregnating carbon fibers into an epoxy resin. In each of the prepreg sheets, the carbon fibers have an orientation that occurs regularly, Figure 1 The solid line in the above view shows the orientation direction of the carbon fibers. Hereinafter, the orientation direction of the carbon fibers is set to be the direction in the state in which the prepreg sheet is spread.

[0077] (First process)

[0078] The first process of the present manufacturing method will be described. The prepreg sheet PS1 is made of two layers of a sheet in which the orientation direction of carbon fibers is in the +45 degree direction with respect to the axis of the mandrel MD and a sheet in which the orientation direction of carbon fibers is in the -45 degree direction, and has a function of resisting the torsional stress that the structure body receives. This prepreg sheet PS1 is wound around the outer periphery of the mandrel MD whose outer periphery has been subjected to peeling treatment as needed.

[0079] The prepreg sheets PS2, PS3, and PS4 each have the orientation direction of carbon fibers parallel to the axis of the mandrel MD, and have a function of resisting the tensile stress that the structure body receives. These prepreg sheets PS2, PS3, and PS4 are sequentially wound around the prepreg sheet PS1.

[0080] In the prepreg sheet PS5, the orientation direction of carbon fibers is orthogonal to the axis of the mandrel MD, and has a function of resisting the expansion when the structure body receives the compressive stress. This prepreg sheet PS5 is wound around the prepreg sheet PS4.

[0081] In the pair of prepreg sheets PS6, the orientation direction of carbon fibers is orthogonal to the axis of the mandrel MD, and has a trapezoidal shape. These prepreg sheets PS6 are wound around both ends of the prepreg sheet PS5.

[0082] The structure body of the present embodiment can have a mounting member (to be described later) or the like mounted at both end portions thereof, and thus, by winding the outermost prepreg sheet PS6 around only both end portions, the reinforcing effect is achieved. The number of prepreg sheets and the orientation direction of carbon fibers can be appropriately changed according to the mechanical strength of the desired structure body.

[0083] By so doing, a cylindrical laminated body LM (see FIG. 2) in which a plurality of prepreg sheets are wound around the mandrel MD is formed. Figure 2 ).

[0084] (Second process)

[0085] The second process of the present manufacturing method will be described. Figure 2 FIG. 2 is a diagram schematically showing the second process. Figure 2 In FIG. 2, one end of the mandrel MD around which the laminated body LM is wound is coupled to a rotation drive body RD such as a motor rotation shaft, and one end of a thin tape TP (which is transparent in this case) is attached to the outer periphery of the laminated body LM.

[0086] From this state, the mandrel MD rotates together with the rotary drive RD, applying a specified tension and winding the strip TP to the outer periphery of the laminate LM. The specified tension varies depending on conditions such as the outer diameter of the laminate LM, and is preferably in the range of 1 to 5 kgf. By compressing the prepreg sheets PS1 to PS6 thus laminated, voids between the prepreg sheets can be eliminated, thereby achieving densification of the laminate LM.

[0087] Furthermore, by causing the strip TP to move relative to the axis O of the mandrel MD, the strip TP is wound around the axis O of the laminate LM as a whole, forming a thin layer with approximately uniform thickness.

[0088] The means of pressurizing the laminate LM wound onto the mandrel MD is not limited to strips. For example, a tube or the like formed of a heat-shrinkable film can be placed around the laminate LM, and the laminate LM can be compressed by heating the heat-shrinkable film to shrink it.

[0089] Alternatively, rubber strips or films, formed into tubes (rubber tubes), can be placed around the laminate LM, using their elastic force to compress the laminate LM. This eliminates the need for a rotary drive to rotate the mandrel MD, thus reducing equipment costs.

[0090] (Third process)

[0091] The third step of this manufacturing method will be described. Figure 3 This diagram schematically illustrates the third step. A laminate LM wound with strip TP and a mandrel MD are placed together in an oven OV. The prepreg sheet of the laminate LM is heated in the oven OV until the resin is in a state before complete curing. More specifically, heating is performed such that the degree of curing of the thermosetting resin of the laminate LM reaches 30-90%.

[0092] Here, we will explain the degree of curing of thermosetting resins. For example, when uncured epoxy resin is heated from room temperature to 200°C at a rate of 5°C / minute, if the heat flow (exothermic or endothermic) is measured using DSC (differential scanning calorimetry), it can be seen that the phenomenon characteristic of thermosetting resins will occur.

[0093] Specifically, such as Figure 4 As shown in the DSC curve, a dramatic exothermic reaction occurs from around 103°C, with an exothermic peak at 110.7°C, after which the exothermic reaction decreases sharply. This exothermic reaction indicates polymerization (curing) of the epoxy resin due to heating. Here, 110.7°C is referred to as the maximum exothermic temperature of this epoxy resin.

[0094] It can be seen that if the epoxy resin is cooled to room temperature again and then heated to 200°C at a rate of 5°C / minute, then...Figure 5 As shown in the DSC curve, no exothermic peak occurs, but an endothermic peak occurs, and a glass transition occurs at 116.1°C. This is a phenomenon that occurs because the epoxy resin has been completely cured. ("Investigation of Curing Temperature and Glass Transition Temperature of Epoxy Resin", MST Technical Material: No. C0220, Date of Publication: 2011 / 10 / 20, Incorporated Foundation: Materials Science and Technology Foundation)

[0095] On the other hand, if the heating is interrupted before the epoxy resin is completely cured, the exothermic peak becomes an X°C that is less than 110.7°C. Figure 4 This indicates that there is room for further polymerization of the epoxy resin, that is, the epoxy resin assumes a state before complete curing.

[0096] In other words, by measuring the exothermic peak of the thermosetting resin while heating, and interrupting the heating at an X°C that is less than the maximum exothermic temperature, it is possible to leave the thermosetting resin in a state before complete curing.

[0097] Figure 4 In the meantime, when the area (referred to as the exothermic peak area) surrounded by the DSC curve at the time of complete curing and the baseline BS is denoted as S1, and the area surrounded by the DSC curve at the exothermic peak of X°C and the baseline BS is denoted as S2, (S2 / S1) x 100% is defined as the degree of curing of the thermosetting resin.

[0098] The present inventors have found that, by utilizing the thermal characteristics of the thermosetting resin, by interrupting the heating of the laminate LM before the thermosetting resin is completely cured, for example, at a degree of curing of 30 to 90%, the moldability of the laminate LM is improved. The exothermic peak X°C corresponding to a degree of curing of 30 to 90% can be obtained by experiments, simulations. The effect of improving the moldability of the laminate LM is described in association with the fifth process.

[0099] (Fourth Process)

[0100] The fourth process of the present production method will be described. Figure 6 is a view that schematically shows the fourth process. The laminate LM, on which the tape TP is wound, is taken out of the oven OV, and the mandrel MD is pulled out as shown in Figure 6 The tape TP is wound at a prescribed tension on the outer periphery of the laminate LM, and in addition, in the third process, the thermosetting resin of the laminate LM was heated at a degree of curing of 30% or more, and therefore, the laminate LM has rigidity that enables the cylindrical shape to be maintained even if the mandrel MD is pulled out. This cylindrical shape is referred to as a preform.

[0101] In order to prevent deterioration of the resin material, the laminate LM without heating needs to be stored in a refrigerator or a freezer. On the other hand, the preform formed through the fourth process is a preform in which the degree of curing of the resin material is adjusted, and there is almost no deterioration of the resin material even when stored at room temperature. Therefore, by mass-producing the preform in advance and storing it, it is possible to cope with the supply of the product on demand.

[0102] Further, since it is possible to form a plurality of structures from one preform, reduction of manufacturing cost is achieved.

[0103] (Fifth Process)

[0104] The fifth process of the present manufacturing method will be described. Figures 7-9 is a view schematically showing the fifth process. First, as shown in Figure 7 , a cylindrical rubber body GM is inserted into the laminate LM after the mandrel MD is pulled out. The cylindrical rubber body GM having substantially the same diameter as the mandrel MD has a property of expanding when heated.

[0105] Further, as shown in Figure 8 , the laminate LM in which the rubber body GM is inserted is disposed between the plate-shaped upper die UD and the groove-shaped lower die LD. The upper die UD and the lower die LD constitute a molding die.

[0106] Here, when the width of the groove bottom surface in the lower die LD is denoted as W, the height of the groove inner wall is denoted as H, and the outer diameter of the laminate LM in which the tape TP is wound is denoted as D, if πD≈2(W+H), it is possible to make the inner circumference of the die and the outer circumference of the final structure substantially identical, and thus it is possible to obtain a structure having a stable shape.

[0107] Thereafter, as shown in Figure 9 , the upper die UD and the lower die LD are brought into close proximity to each other to perform die closing. At this time, since the thermosetting resin of the laminate LM was heated at a degree of curing of 90% or less in the previous third process, it is possible to deform the laminate LM in a manner conforming to the inner wall shape formed by the upper die UD and the lower die LD. On the other hand, since the tape TP is wound at a prescribed tension, the laminate LM will not be damaged by the pressure of the upper die UD and the lower die LD.

[0108] Further, by heating the inside of the upper die UD and the lower die LD using a heater not shown, the rubber body GM expands, and thus the internal pressure of the laminate LM increases. Due to this, the laminate LM is pressed toward the inner wall surfaces of the upper die UD and the lower die LD, and in particular, the gap between the corner portions CR of the inner wall shape of the upper die UD and the lower die LD and the laminate LM is filled, and it is possible to deform the laminate LM into a square tube shape with high precision. Further, by heating the laminate LM, it is possible to completely cure it.

[0109] At this time, since the tape TP having high sliding properties is wound around the periphery of the laminate LM that receives internal pressure, even if relative displacement occurs between the outer surface of the laminate LM and the inner wall surface of the molding die as the rubber body GM expands, the two can slide against each other with almost no resistance. Thus, the mold adaptability of the laminate LM is improved, and a stable product shape can be obtained. Furthermore, even if a gap is generated between the laminate LM and the upper die UD or the lower die LD, since the tape TP wound around the periphery of the laminate LM can withstand the internal pressure of the rubber body GM, the laminate LM can be effectively prevented from being wrinkled, having a void, or having a resin-rich portion, and the like, which are particularly likely to occur in the vicinity of the corner CR.

[0110] On the other hand, since the mold adaptability of the laminate LM is improved, the pressure of the molding die can be reduced, and the strength and rigidity of the die can be reduced, so the degree of freedom in the selection of the material of the die can be increased. Furthermore, the equipment for driving the molding die can be simplified, so the cost of the equipment can be reduced.

[0111] Furthermore, due to the shape retaining function of the tape TP, the intersection between the side surface (first surface) of the laminate LM formed by pressing the corner CR at a right angle and the upper and lower surfaces (second surface different from the first surface in the normal direction) has a curved surface in which the curvature is fixed or gradually changes (i.e., an edge is not formed at the intersection). Furthermore, since the reinforcing fibers at the intersection are bent without being broken (the continuity of the fibers is maintained), the strength of the structure can be ensured.

[0112] (Sixth Step)

[0113] Thereafter, the heating is stopped, and the upper die UD and the lower die LD are separated from each other, and the laminate LM deformed into a cylindrical shape is taken out. The rubber body GM shrinks when it is cooled, so it can be easily pulled out from the cured laminate LM. Furthermore, by peeling the tape TP from the laminate LM, a structure ST1 in which the laminate LM is covered with the tape TP is completed. Figure 10 The structure ST1 is shown in part.

[0114] Note that, instead of the rubber body GM, an air bag or the like that expands by injecting air or the like can be used.

[0115] (Modified Example)

[0116] By attaching an attachment member to the structure ST1 formed by the above operation, the structure ST1 can be connected to other members. Figure 11 is a diagram schematically showing the fifth step of the modified example. Here, an attachment member AT made of metal or the like is prepared in advance.

[0117] The mounting member AT has a shape in which a plate portion PT of a thin pointed shape is integrally joined to a ring-shaped head portion RG. Grooves GV are formed in the upper and lower surfaces of the plate portion PT, respectively.

[0118] Referring to Figure 7 , the laminated body LM is disposed between the upper die UD and the lower die LD without the aid of a rubber body, the plate portion PT of the mounting member AT is inserted into the laminated body LM (a) and the plate portion PT is inserted into the laminated body LM (b). Figure 11 Figure 11 Subsequently, as shown in , the upper die and the lower die are clamped, and the laminated body LM is caused to adhere to the plate portion PT while being heated. A portion of the inner peripheral surface of the laminated body LM, which is relatively soft, forms protrusions PJ that enter the grooves GV of the plate portion PT, and solidification occurs in this state. The protrusions PJ constitute engaging portions (c).

[0119] Figure 9 As a result, the mounting member AT cannot be pulled out of the laminated body LM. Subsequently, by peeling off the tape in the sixth step, the structure ST1 shown in Figure 11 , which has a bundle shape, can be obtained.

[0120] The structure ST1 shown in Figure 12 can be provided by bolt fastening the head portion RG of the mounting member AT to other components, not shown.

[0121] Figure 12 The structure ST1 shown in can be provided by bolt fastening the head portion RG of the mounting member AT to other components, not shown.

[0122] [Second Embodiment]

[0123] The manufacturing method of the structure described in the second embodiment will be described. Figure 13 , 14 is a view schematically showing the fifth step of the second embodiment. In the second embodiment, the first to fourth steps are the same as in the first embodiment. In other words, the preform formed by the first to fourth steps can be common.

[0124] (Fifth Step)

[0125] The preform after the core rod MD is pulled out, i.e., the laminated body LM formed by the fourth step, is disposed between the plate-shaped upper die UD and the plate-shaped lower die LD without inserting a rubber body or the like, as shown in Figure 13 .

[0126] Subsequently, the upper die UD and the lower die LD are brought into close proximity in a parallel state to perform clamping. Since the inside of the laminated body LM is hollow, it is pressed by the lower surface of the upper die UD and the upper surface of the lower die LD as shown in Figure 14 , the laminated body LM forms a plate shape, and the hollow inside disappears.

[0127] At this time, since the thermosetting resin of the laminate LM was heated with a curing degree of 90% or less in the third process, the laminate LM is allowed to be pressed into a large deformation like a flat plate.

[0128] Further, since the strip TP has a shape retaining function, even if the laminate LM is pressed into a flat plate, the outer surface of both edges ED of the laminate LM at the intersection of the upper surface (first surface) and the lower surface (second surface different from the first surface in the normal direction) of the laminate LM also has a curved surface with a fixed or slowly changing curvature. In other words, in a cross section orthogonal to the axis of the laminate LM, the normal line extending from the first plane to the outside and the normal line extending from the second plane to the outside are directed in different directions. Therefore, the appearance quality of the structure and the strength against bending and twisting can be improved. Further, the reinforcing fibers of both edges ED are also bent but not broken (maintaining the continuity of the fibers), thereby a higher strength can be ensured.

[0129] (Sixth process)

[0130] Thereafter, by separating the upper mold UD from the lower mold LD, the laminate LM deformed into a plate is taken out, and further the strip TP is peeled off from the laminate LM, thereby completing the structure ST2 in Figure 15 A structure ST2 like a part thereof is shown in FIG. 6. The structure ST2 can be holed near both ends thereof and bolted to other members.

[0131] Figure 16 is a plan view of the structure ST2, and for one continuous reinforcing fiber FB, the surface side is represented by a solid line and the back side is represented by a dotted line. In the present embodiment, the structure ST2 is formed by pressing the cylindrical laminate LM. Therefore, the reinforcing fiber FB wound in a spiral shape around the circumference of the cylindrical laminate LM is pressed at an arbitrary position, and according to the geometric relationship thereof, as shown in Figure 16 the inclination angle θ1 of the surface side reinforcing fiber FB is equal to the inclination angle θ2 of the back side reinforcing fiber FB. Thereby, the deformation of the structure ST2 is suppressed, and a flat plate shape with good precision can be maintained. Note that the position where the surface side planar portion and the back side planar portion intersect is the intersection portion having a curved surface outer surface, and the reinforcing fiber FB extends from the surface side planar portion to the back side planar portion through the intersection portion.

[0132] (Modified example)

[0133] Figure 17 , 18 is a cross-sectional view showing a modified example of the second embodiment. By changing the shape of the molding die that presses the cylindrical laminate LM, it is possible to Figure 17The structure ST2 having a cross section in an L shape is formed as shown in FIG. 2A, or the structure ST2 having a cross section in a C shape is formed as shown in FIG. 2B. Figure 18 The structure ST2 having a cross section in an L shape is formed as shown in FIG. 2A, or the structure ST2 having a cross section in a C shape is formed as shown in FIG. 2B.

[0134] Figure 19 A cross-sectional view of a structure according to another modification example is shown in FIG. 3. The structure ST3 according to the modification example is formed by inserting a semicircular pipe-shaped metal plate of a different material into the inside of the laminate LM at the time of molding, and pressing the laminate LM with an upper mold and a lower mold. The laminate LM is pressed into a flat plate shape by the mold, and the metal plate is also formed flat to form a flat plate FP. At this time, the inner surface of the laminate LM is bonded to the upper surface and the lower surface of the flat plate FP. Instead of the semicircular pipe-shaped metal plate, a flat plate or a plate of a raw material other than metal can be inserted. Figure 14 The structure ST3 according to the modification example can be elastically deformed by the flat plate FP to suppress immediate breakage or the like of the structure ST3 even when an excessive stress exceeding the allowable stress of the laminate LM acts.

[0135]

[0136] Figure 20 A cross-sectional view of a structure according to another modification example is shown in FIG. 3. The structure ST3 according to the modification example is formed by inserting a semicircular pipe-shaped metal plate of a different material into the inside of the laminate LM at the time of molding, and pressing the laminate LM with an upper mold and a lower mold. The laminate LM is pressed into a flat plate shape by the mold, and the metal plate is also formed flat to form a flat plate FP. At this time, the inner surface of the laminate LM is bonded to the upper surface and the lower surface of the flat plate FP. Instead of the semicircular pipe-shaped metal plate, a flat plate or a plate of a raw material other than metal can be inserted. Figure 20

[0137] At this time, the inner diameter of the laminate LM before molding is larger than the outer diameter of the pipe PP, and thus the laminate LM has a margin after molding. Therefore, if the laminate LM is partially molded into a flat plate shape using a mold so that the inner periphery of the excess amount of the laminate LM is bonded, the structure ST4 has a flat portion FL extending in the diameter direction from the pipe PP. According to the present embodiment, when the pipe PP is used as a pipe for passing a fluid, for example, a hole can be opened in the flat portion FL and bolted to a structure.

[0138] The present application is not limited to the above embodiments. For example, for a mounting member mounted to a structure, in addition to providing a groove, an arbitrary concave-convex shape such as a hole or a dimple can be provided, and a fitting portion that fits into the concave-convex shape in a concave or convex shape can be provided to the structure.​​

Claims

1. A method for manufacturing a structure, comprising: a first step of winding a plurality of sheets each of which comprises a reinforcing fiber and an uncured thermosetting resin around a periphery of a mandrel to form a cylindrical laminated body; a second step of pressing a tape or a film around the entire periphery of the laminated body; a third step of heating the laminated body until the thermosetting resin is completely cured, so that the laminated body has rigidity to maintain a cylindrical shape even after the mandrel is removed from the laminated body; a fourth step of removing the mandrel from the laminated body; a fifth step of disposing the laminated body, around which the tape or the film is wound, in a molding die in a state in which a hollow is formed in the inside of the laminated body, and pressing the laminated body with the molding die in a manner that no space is provided in the inside of the laminated body, or inserting a plate or a pipe into the laminated body around which the tape or the film is wound, and pressing the laminated body with the molding die in a manner that the laminated body is in close contact with the plate or the pipe and at least a part of the laminated body becomes a flat plate, and heating the laminated body until the thermosetting resin is completely cured; and a sixth step of taking the laminated body out of the molding die and peeling off the tape or the film. The sheet is a prepreg in which the thermosetting resin is impregnated into the reinforcing fiber. In the second step, the tape is wound around the periphery of the laminated body while rotating the mandrel and applying a predetermined tension. In the second step, a pipe formed of a heat-shrinkable film is disposed around the periphery of the laminated body, and the heat-shrinkable film is heated. In the third step, the laminated body is heated in a manner that the degree of curing of the thermosetting resin is in a range of 30% to 90%. The structure is formed of a thermosetting resin impregnated into a reinforcing fiber, and has a first plane and a second plane formed by pressing with a pair of parallel molds, and in a cross section orthogonal to an axis of the structure, a normal line extending from the first plane to the outside and a normal line extending from the second plane to the outside are directed in different directions. An intersection of the first plane and the second plane has a curved surface whose curvature is fixed or gradually changes, and the reinforcing fiber continuously passes through the intersection without being broken. The structure is a plate, and has no space in the inside.

2. The method for producing a structure according to claim 1, wherein The structure is a plate, and contains a plate material in the inside.

3. The method for producing a structure according to claim 1, wherein The structure has a pipe and a tubular body formed of the thermosetting resin impregnated into the reinforcing fiber, 4. The method for producing a structure according to claim 1, wherein An outer peripheral surface of the pipe is in close contact with an inner periphery of the tubular body, and a part of the inner periphery of the tubular body is in close contact with each other and forms a flat portion in a flat plate shape.

5. The method for producing a structure according to claim 1, wherein The structure is engaged with a mounting member for joining other members, and has a concave or convex engaging portion in the inside of the structure.

6. The method for producing a structure according to claim 1, wherein An outer surface of the other member inserted into the inside of the structure formed of the thermosetting resin impregnated into the reinforcing fiber is in close contact with the thermosetting resin. The structure is formed of a thermosetting resin impregnated into a reinforcing fiber, has at least two plane portions bent at an intersection, and is formed in a flat plate shape, 7. The method for producing a structure according to claim 6, wherein The intersection has a curved outer surface, 8. The method for producing a structure according to claim 6, wherein ​ 9. The method for producing a structure according to claim 6, wherein ​ ​ 10. The method for producing a structure according to claim 6, wherein ​ 11. The method for producing a structure according to claim 6, wherein ​ 12. The method for producing a structure according to claim 1, wherein ​ ​ The reinforcing fibers extend from one of the planar portions through the intersection portion to the other planar portion.

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