JP6747722B2 - Method of manufacturing structure and structure - Google Patents

Description

The present invention relates to a method of manufacturing a structure and a structure.

From the viewpoint of reducing the weight of parts, there is an attempt to replace a metal structure with a structure made of FRP (Fiber Reinforced Plastics) in which reinforcing fibers such as carbon fibers are hardened with a resin. Here, as a structure made of FRP, for example, a hollow cylindrical member already used in a frame of a bicycle is known.

However, since the frame of the bicycle is originally made by connecting metal round pipes, it is relatively easy to replace it with the hollow cylindrical member made of FRP except for the problem of the joint. On the other hand, a structure used in, for example, a vehicle has a problem that it is difficult to use the hollow cylindrical member as it is because the installation space is limited. Therefore, in order to enable a wide range of use as a structure, there is a demand for forming a structure made of FRP into a plate shape or a non-circular hollow cross-sectional shape (for example, a rectangular tube shape).

As a plan for forming a plate-shaped FRP structure, there is a method in which a plurality of prepregs are laminated on a plane, adhered to each other, and completely cured. A prepreg is a sheet-shaped reinforced plastic molded product obtained by uniformly impregnating a reinforcing fiber with a thermosetting resin such as epoxy, and heating or drying the prepreg into a semi-cured state.
However, the FRP structure thus formed has a problem that strain is likely to be generated during the curing process and an accurate flat plate shape cannot be obtained.

Further, when the torsional torque is repeatedly applied to both ends of the plate-shaped FRP structure formed by stacking in this way, relative movement occurs between the upper surface side sheet and the lower surface side sheet. For this reason, there is a problem that the adhesion of the sheet is peeled off at both edges of the structure in the center width direction, the fibers are easily peeled off, and the strength is lowered.

On the other hand, as an idea for forming an FRP structure having a non-circular hollow cross-sectional shape, a flexible hollow core having laminated prepregs and the like arranged on the outer periphery thereof is arranged in a molding die, and the hollow core is pressurized. There is a method of forming the outer surface of the prepreg by following the mold by heating the child while expanding it. However, when molding is performed by such a manufacturing method, wrinkles, voids, and resin richness caused by reinforcing fibers that cannot follow the shape change following the mold when the thickness of the prepreg changes in the pressure/heating process during molding May occur. As a result, the product quality and product strength of the FRP structure will be reduced.

On the other hand, as a technique for forming a structure made of FRP having a non-circular hollow cross-sectional shape, one disclosed in Patent Document 1 is disclosed. According to the technique disclosed in Patent Document 1, a hollow core having a reinforcing fiber base material arranged on the outer periphery thereof is disposed in a cavity of a molding die, and after the die is clamped, the inside of the molding die is pressurized while pressurizing the inside of the core. The FRP hollow structure can be molded by injecting a resin into.

JP, 2006-159457, A

According to the technique of Patent Document 1, it is possible to prevent defects such as wrinkles and voids in the FRP hollow structure by injecting the resin into the mold while pressurizing the hollow core arranged in the mold. It is said that. However, such a technique requires a large-scale facility such as a resin flow path for injecting the resin into the molding die, which causes a problem of cost.

Therefore, it is an object of the present invention to provide a method for manufacturing a structure and a structure having high shape accuracy and strength despite low cost.

In order to achieve the above object, the method for producing a structure according to the present invention,
A first step of forming a tubular laminate by winding a plurality of sheets and/or tapes containing reinforcing fibers and an uncured thermosetting resin around a mandrel;
A second step of pressing the entire circumference of the laminate with a tape or a film,
A third step of heating the laminate to a state before the thermosetting resin is completely cured,
A fourth step of extracting the mandrel from the laminate,
A fifth step of placing the laminated body around which the tape or film is wound in a molding die, pressurizing the laminated body, and heating the laminated body until the thermosetting resin is completely cured.

The structure according to the present invention is a structure formed of a thermosetting resin impregnated with a reinforcing fiber and having a first surface and a second surface having different normal directions, and the first surface The intersection of the second surface and the second surface has a curved surface with a constant curvature or a gradual change, and the reinforcing fiber passing through the intersection is continuous without breaking.

The structure according to the invention is
The structure has a tubular shape, is joined to a mounting member for connecting to another component, and has a concave or convex engaging portion that engages with the mounting member inside.

The structure according to the invention is
A plurality of sheets and/or tapes containing reinforcing fibers and an uncured thermosetting resin are wound around a mandrel to form a tubular laminate.
The entire circumference of the laminate is pressed with a tape or a film,
The laminate is heated to a state before the thermosetting resin is completely cured,
Extracting the mandrel from the laminate,
It is formed by placing the laminated body around which the tape or film is wound in a molding die, pressurizing the laminated body, and heating the laminated body until the thermosetting resin is completely cured.
Since it is difficult to directly specify the structure according to the present invention by its structure or characteristics, the structure itself is specified by the manufacturing method of the structure.

According to the present invention, it is possible to provide a method for manufacturing a structure and a structure that have high shape accuracy and strength despite low cost.

FIG. 1 is a diagram showing a first step of the present method for manufacturing a structure according to the present embodiment, and is a plan view of a prepreg and a mandrel. FIG. 2 is a diagram showing a second step of the present method for manufacturing a structure according to the present embodiment. FIG. 3 is a diagram showing a third step of the present method for manufacturing a structure according to the present embodiment. FIG. 4 is a diagram showing an example of a DSC curve relating to an uncured thermosetting resin, in which the vertical axis represents heat flow and the horizontal axis represents temperature. FIG. 5 is a diagram showing an example of the DSC curve of the thermosetting resin after complete curing, in which the vertical axis represents heat flow and the horizontal axis represents temperature. FIG. 6 is a diagram showing a fourth step of the present method for manufacturing a structure according to the present embodiment, showing a state in which the mandrel is extracted from the laminate. FIG. 7: is a figure which shows a part of 5th process of this manufacturing method of the structure concerning this embodiment, and shows the state which inserts a rubber body in a laminated body. FIG. 8 is a cross-sectional view showing a part of the fifth step of the present method for manufacturing a structure according to the present embodiment, and shows the state before mold clamping seen in the axial direction of the laminate. FIG. 9: is sectional drawing which shows a part of 5th process of this manufacturing method of the structure concerning this embodiment, and shows the state which clamped and heated. FIG. 10 is a perspective view of a structure manufactured by the manufacturing method according to this embodiment. FIG. 11 is a cross-sectional view showing a state where the attachment member is attached to the structure. FIG. 12 is a perspective view showing a structure to which a mounting member is attached, and partially showing the laminated body in a transparent manner. FIG. 13 is a cross-sectional view showing a part of the fifth step of the method for manufacturing a structure according to another embodiment, showing a state before die clamping as seen in the axial direction of the laminate. FIG. 14: is sectional drawing which shows a part of 5th process of this manufacturing method of the structure concerning another embodiment, and shows the state which clamped and heated. FIG. 15 is a perspective view of a structure manufactured by a manufacturing method according to another embodiment. FIG. 16 is a plan view of a structure manufactured by the manufacturing method according to another embodiment, which is shown together with the reinforcing fibers. FIG. 17 is a cross-sectional view of a modified structure. FIG. 18 is a cross-sectional view of a modified structure.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
In the present specification, the “reinforcing fiber” is preferably carbon fiber, glass fiber, organic fiber typified by aramid fiber, silicon carbide fiber, metal fiber and the like. Furthermore, the "thermosetting resin" is preferably an epoxy resin, a polyester resin, a vinyl ester resin, a phenol resin, a urethane resin, a polyimide resin, or the like.

The "cylindrical laminate" can be formed by impregnating a reinforcing fiber with a thermosetting resin, heating or drying a prepreg sheet which is in a semi-cured state, and winding the prepreg sheet by a sheet winding method. It can be formed by winding a tape using a tape winding method.
Alternatively, the tubular laminated body can be formed by winding the robinc fiber by a filament winding method in which the resin is impregnated and wound. However, the sheet winding method or the tape winding method is more preferable because a stable prepreg in which the ratio of the resin and the reinforcing fiber is controlled can be used.
As the prepreg, for example, Torayca (registered trademark) manufactured by Toray Industries, Inc. can be preferably used.

The material of the "mandrel" may be any of metal, resin, ceramics and the like, but it is preferable to use metal from the viewpoint of cost and durability. The shape of the mandrel is preferably a solid cylindrical shape or a hollow cylindrical shape, and may be a dividable shape instead of a single shape.

In the present specification, the "tape or film" refers to a thin member regardless of material. However, it is preferable to use a tape from the viewpoint of ease of use. The tape may be made of resin or metal, but it is preferable to use a resin tape having good workability. When using a resin tape, any of polypropylene, polyethylene, polyester, cellophane, Teflon (registered trademark), polyimide, etc. may be used, but polypropylene and polyester are preferably used because of the good balance of the tape properties.

[First Embodiment]
A method of manufacturing the structure according to the first embodiment will be described. FIG. 1 is a diagram schematically showing the first step. As shown in FIG. 1, a mandrel MD and various prepreg sheets PS1 to PS6 are prepared.

The outer diameter of the mandrel MD is set to be slightly shorter than the outer peripheral length of the finally formed structure in consideration of the thickness of the laminated body wound on the outside. That is, it is desirable that the outer diameter of the mandrel MD in which a plurality of prepreg sheets are wound is approximately equal to the design value of the outer peripheral length of the finally formed structure.

As the prepreg sheets PS1 to PS6, sheets obtained by impregnating carbon fiber into a raw material of epoxy resin are used here. In each prepreg sheet, carbon fibers are oriented with regularity, and the solid line in FIG. 1 indicates the orientation direction of the carbon fibers. Hereinafter, the orientation direction of the carbon fibers is referred to as a state in which the prepreg sheet is developed.

(First step)
The first step of the manufacturing method will be described. The prepreg sheet PS1 is a sheet in which the orientation of carbon fibers is +45 degrees with respect to the axis of the mandrel MD and the sheet in the -45 degrees direction is laminated in two layers to form one prepreg sheet. It acts to resist the torsional stress that the body receives. This prepreg sheet PS1 is wrapped around the outer periphery of the mandrel MD whose outer periphery has been subjected to a peeling treatment, if necessary.

The prepreg sheets PS2, PS3, and PS4 each have an orientation direction of carbon fibers parallel to the axis of the mandrel MD, and have an action of resisting tensile stress received by the structure. The prepreg sheets PS2, PS3 and PS4 are sequentially wound around the prepreg sheet PS1.

In the prepreg sheet PS5, the orientation direction of the carbon fibers is orthogonal to the axis of the mandrel MD, and the prepreg sheet PS5 has an action of resisting expansion when the structure receives compressive stress. This prepreg sheet PS5 is wound around the prepreg sheet PS4.

The pair of prepreg sheets PS6 has a trapezoidal shape in which the orientation direction of the carbon fibers is orthogonal to the axis of the mandrel MD. The prepreg sheet PS6 is wound around both ends of the prepreg sheet PS5.

In the structure of the present embodiment, attachment members (described later) and the like can be attached to both ends thereof, so that the outermost prepreg sheet PS6 is wound only on both ends to enhance the reinforcing effect. The number of prepreg sheets and the orientation direction of carbon fibers can be appropriately changed according to the desired mechanical strength of the structure.

In this way, a cylindrical laminated body LM (FIG. 2) formed by winding a plurality of prepreg sheets on the mandrel MD is formed.

(Second step)
The second step of the manufacturing method will be described. FIG. 2 is a diagram schematically showing the second step. In FIG. 2, one end of a mandrel MD around which the laminated body LM is wound is connected to a rotary driving body RD such as a motor rotating shaft, and one end of a thin tape TP (here, transparent) is attached to the outer periphery of the laminated body LM. ..

From this state, the mandrel MD is rotated together with the rotary drive body RD, and the tape TP is wound around the outer periphery of the laminated body LM while applying a predetermined tension. The predetermined tension varies depending on the conditions such as the outer diameter of the laminated body LM, but is preferably in the range of 1 to 5 kgf. By pressing the laminated prepreg sheets PS1 to PS6 in this way, it is possible to eliminate voids between the prepreg sheets and to densify the laminated body LM.

Further, by relatively moving the tape TP along the direction of the axis O of the mandrel MD, the tape TP is wound around the entire direction of the axis O of the laminated body LM to form a thin layer having a substantially uniform thickness.

However, the means for pressing the laminated body LM wound around the mandrel MD is not limited to the tape. For example, a tube or the like made of a heat-shrinkable film may be arranged around the laminate LM, and the heat-shrinkable film may be shrunk by heating to press the laminate LM.

Alternatively, a rubber tape or a tube of a rubber film (rubber tube) may be arranged around the laminated body LM, and the elastic force may press the laminated body LM. This eliminates the need for a rotary drive that rotates the mandrel MD, and reduces equipment costs.

(Third step)
The third step of the manufacturing method will be described. FIG. 3 is a diagram schematically showing the third step. The laminated body LM wound with the tape TP is arranged in the oven OV together with the mandrel MD. The resin of the prepreg sheet of the laminate LM is heated to a state before complete curing by heating in an oven OV. More specifically, the thermosetting resin of the laminated body LM is heated so that the degree of curing is 30 to 90%.

Here, the degree of cure of the thermosetting resin will be described. For example, when uncured epoxy resin is heated from room temperature to 200°C at a rate of 5°C/min, the heat flow (exothermic or endothermic) is measured using DSC (differential scanning calorimetry). It can be seen that a phenomenon peculiar to the organic resin occurs.
Specifically, as in the DSC curve shown in FIG. 4, abrupt heat generation occurs at about 103° C., a heat generation peak occurs at 110.7° C., and thereafter heat generation sharply decreases. This heat generation means that the epoxy resin is polymerized (cured) by heating and heating. Here, 110.7° C. is called the maximum exothermic temperature of this epoxy resin.

When this epoxy resin was cooled to room temperature again and heated again to 200° C. at a rate of 5° C./min, an exothermic peak did not appear as in the DSC curve shown in FIG. It can be seen that a glass transition occurs at 1°C. This is a phenomenon that occurs because the epoxy resin has already been completely cured. ("Epoxy resin curing temperature/glass transition temperature investigation", MST technical data: No. C0220, publication date: 2011/10/20, foundation: Materials Science and Technology Foundation)

On the other hand, if heating is interrupted before the epoxy resin is completely cured, the exothermic peak becomes X°C below 110.7°C (Fig. 4). This indicates that the epoxy resin has room for further polymerization, that is, the epoxy resin is in a state before complete curing.
In other words, the exothermic peak when the thermosetting resin is heated is measured at any time, and when the temperature reaches X°C, which is lower than the maximum exothermic temperature, the heating is interrupted to completely cure the thermosetting resin. You can stay in the same state as before.

In FIG. 4, when the area enclosed by the DSC curve at the time of complete curing and the baseline BS (called the exothermic peak area) is S1, and the area enclosed by the DSC curve whose exothermic peak is X° C. and the baseline BS is S2, , (S2/S1)×100% is defined as the degree of cure of the thermosetting resin.

The present inventors utilize the thermal characteristics of the thermosetting resin to interrupt the heating of the laminated body LM before the thermosetting resin is completely cured, for example, at a curing degree of 30 to 90%. It was found that the formability of the laminated body LM is improved. The exothermic peak X° C. corresponding to the curing degree of 30 to 90% can be obtained by experiments or simulations. The effect of improving the formability of the laminated body LM will be described later in relation to the fifth step.

(Fourth step)
The fourth step of the manufacturing method will be described. FIG. 6 is a diagram schematically showing the fourth step. The laminated body LM wound with the tape TP is taken out from the oven OV, and the mandrel MD is pulled out as shown in FIG. Since the tape TP is wound around the outer periphery of the laminated body LM with a predetermined tension, and the thermosetting resin of the laminated body LM is heated with the degree of curing of 30% or more in the third step, the laminated body LM is The rigidity is such that the tubular shape can be maintained even if the mandrel MD is pulled out. This tubular shape is called a preform body.

The unheated laminate LM needs to be stored in a refrigerator or a freezer to prevent deterioration of the resin material. On the other hand, in the preform body formed through the fourth step, 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 and storing preforms, it becomes possible to supply products in response to sudden demand.

Moreover, since a plurality of types of structures can be formed from one type of preform, manufacturing cost can be reduced.

(Fifth step)
The fifth step of the manufacturing method will be described. 7 to 9 are diagrams schematically showing the fifth step. First, as shown in FIG. 7, the cylindrical rubber body GM is inserted into the laminated body LM from which the mandrel MD is pulled out. The rubber body GM, which has a cylindrical shape having substantially the same diameter as the mandrel MD, has a characteristic of expanding when heated.

Further, as shown in FIG. 8, the laminated body LM in which the rubber body GM is inserted is arranged between the plate-shaped upper mold UD and the gutter-shaped lower mold LD. A molding die is composed of the upper die UD and the lower die LD.
Here, when the width of the gutter bottom surface in the lower die LD is W, the height of the gutter inner wall is H, and the outer diameter of the laminated body LM around which the tape TP is wound is D, πD≈2 (W+H). And the inner peripheral length of the mold and the outer peripheral length of the final structure can be made substantially equal to each other, whereby a structure having a stable shape can be obtained.

After that, as shown in FIG. 9, the upper mold UD and the lower mold LD are relatively brought close to each other to perform mold clamping. At this time, since the thermosetting resin of the laminated body LM is heated at the degree of cure of 90% or less in the third step, the inner wall shape formed by the upper mold UD and the lower mold LD is imitated. The laminated body LM can be deformed. On the other hand, since the tape TP is wound with a predetermined tension, the laminated body LM is not crushed by the pressure of the upper mold UD and the lower mold LD.

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, thereby increasing the internal pressure of the laminated body LM. As a result, the laminated body 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 laminated body LM and the corner portion CR of the inner wall shape of the upper die UD and the lower die LD. It can be clogged and can be accurately deformed so that the laminated body LM has a rectangular tube shape. Moreover, by heating the laminated body LM, it can be completely cured.

At this time, since the tape TP having high slidability is wound around the laminated body LM that has received the internal pressure, the outer surface of the laminated body LM and the inner wall surface of the molding die are expanded as the rubber body GM expands. Even if a relative displacement occurs between them, it is possible to cause a slip between the two with almost no resistance. Thereby, the mold familiarity of the laminated body LM is improved and a stable product shape can be obtained. Even if a gap is formed between the laminated body LM and the upper die UD or the lower die LD, the tape TP wound around the outer periphery of the laminated body LM can receive the internal pressure of the rubber body GM, and therefore, the corners are particularly sharp. It is possible to effectively suppress defects such as wrinkles, voids, and resin richness of the stacked body LM, which often occur in the vicinity of the portion CR.

On the other hand, since the mold familiarity of the laminated body LM is improved, the pressure of the molding die can be reduced, and the strength and rigidity of the die can be reduced, so that the degree of freedom in selection of usable die materials is expanded. Further, the equipment for driving the molding die can be simplified, so that equipment cost can be reduced.

Further, due to the shape retaining function of the tape TP, the side surface (first surface) and the upper and lower surfaces (first surface of which the normal direction differs from the first surface) of the laminated body LM formed by being strongly pressed against the right angle corner CR. 2) has a curved surface whose curvature is constant or gradually changes (that is, no edge is formed at the intersection). Moreover, the strength of the structure can be secured by bending the reinforcing fibers at the intersections without breaking (continuity of the fibers is maintained).

(Sixth step)
Then, the heating is stopped, the upper mold UD and the lower mold LD are separated from each other, and the laminated body LM deformed into each cylindrical shape is taken out. Since the rubber body GM contracts when cooled, it can be easily extracted from the cured laminated body LM. Further, by peeling off the tape TP from the laminated body LM, the structure ST1 shown in part in FIG. 10 is completed.
Instead of the rubber body GM, an airbag that inflates by injecting air or the like may be used.

(Modification)
By attaching the attachment member to the structure body ST1 formed as described above, connection with other components becomes possible. FIG. 11: is a figure which shows the 5th process concerning a modification typically. Here, a mounting member AT made of metal or the like is prepared in advance.

The attachment member AT has a shape in which a tapered plate portion PT is integrally joined to a ring-shaped head portion RG. Grooves GV are formed on the upper and lower surfaces of the plate portion PT, respectively.

Referring to FIG. 7, when the laminated body LM is arranged between the upper die UD and the lower die LD without interposing a rubber body, the plate portions PT of the attachment member AT are opposed to both ends thereof (see FIG. 11(a)), and the plate portion PT is inserted into the laminated body LM (FIG. 11(b)).

Then, as shown in FIG. 9, when the upper die and the lower die are clamped and the laminate LM is brought into close contact with the plate portion PT while heating, one of the inner peripheral surfaces of the laminate LM which is still relatively soft. The portion becomes a projection PJ, enters the groove GV of the plate portion PT, and solidifies in that state. The protrusion PJ constitutes an engaging portion (FIG. 11(c)).

As a result, the attachment member AT does not come off from the stacked body LM. After that, the tape is peeled off in the sixth step to obtain a beam-shaped structure ST1 as shown in FIG.

The structure ST1 shown in FIG. 12 can be installed by bolting the head portion RG of the attachment member AT and another component (not shown).

[Second Embodiment]
A method of manufacturing the structure according to the second embodiment will be described. 13 and 14 are diagrams schematically showing a fifth step according to the second embodiment. In the second embodiment, the first to fourth steps are the same as those in the first embodiment. That is, the preform bodies formed in the first to fourth steps can be commonly used.

(Fifth step)
As shown in FIG. 13, the laminated body LM, which is the preform body obtained by pulling out the mandrel MD and formed in the fourth step, is inserted into the plate-shaped upper die UD and the plate-shaped lower die LD as shown in FIG. Place it between and.

After that, the upper mold UD and the lower mold LD are relatively brought close to each other in a parallel state to perform mold clamping. Since the inside of the stacked body LM is hollow, it is crushed by the lower plane of the upper die UD and the upper plane of the lower die LD as shown in FIG. The cavity disappears.

At this time, since the thermosetting resin of the laminated body LM is heated at a curing degree of 90% or less in the third step, a large deformation such as the laminated body LM being crushed into a flat plate shape is allowed.

Further, even if the laminated body LM is crushed into a flat plate shape by the shape retaining function of the tape TP, the upper surface (first surface) and the lower surface (first surface) of the laminated body LM are different from each other in the second direction. The outer surface of both edges ED of the laminated body LM, which is the intersection of the surfaces), has a curved surface with a constant curvature or a gradual change. Therefore, the appearance quality of the structure and the strength against bending and twisting can be improved. Further, the reinforcing fibers passing through the both edges ED are also bent (the continuity of the fibers is maintained) without breaking, so that higher strength can be secured.

(Sixth step)
After that, the upper mold UD and the lower mold LD are separated from each other, the laminated body LM deformed into a plate shape is taken out, and the tape TP is further peeled off from the laminated body LM. Complete. The structure ST2 can be bolted to other parts by drilling holes near both ends thereof.

FIG. 16 is a top view of the structure ST2, in which one continuous reinforcing fiber FB passing through the front surface side is shown by a solid line, and one passing through the back surface side is shown by a dotted line. In the present embodiment, the structure ST2 is formed by crushing the cylindrical laminated body LM. Therefore, even if the reinforcing fiber FB spirally wound around the cylindrical laminated body LM is crushed at any position, the reinforcing fiber FB of the surface side FB as shown in FIG. The inclination angle θ1 is equal to the inclination angle θ2 of the reinforcing fiber FB on the back surface side. As a result, the distortion of the structure ST2 is suppressed, and the flat plate shape with high accuracy can be maintained.

(Modification)
17 and 18 are cross-sectional views showing a modified example of the second embodiment. By changing the shape of the molding die that crushes the cylindrical laminated body LM, a structure ST2 having an L-shaped cross section is formed as shown in FIG. 17, or a C-shaped cross section is formed as shown in FIG. The structure ST2 can be formed.

The present invention is not limited to the above embodiment. For example, the mounting member to be attached to the structure may be provided with an arbitrary concavo-convex shape such as a hole or dimple in addition to the groove, and the structure may be provided with a concave or convex engaging portion that engages with the concavo-convex shape.

PS1 to PS6 prepreg sheet MD mandrel TP tape OV oven RD rotation driver GM rubber body UD upper mold LD lower mold AT mounting member ST1, ST2 structure

Claims (13)

A first step of forming a tubular laminate by winding a plurality of sheets and/or tapes containing reinforcing fibers and an uncured thermosetting resin around a mandrel;
A second step of pressing the entire circumference of the laminate with a tape or a film,
A third step of heating the laminate to a state before the thermosetting resin is completely cured,
A fourth step of extracting the mandrel from the laminate,
A fifth step of heating the laminated body until the thermosetting resin is completely cured by placing the laminated body around which the tape or film is wound in a molding die and pressurizing the laminated body.
Method of manufacturing structure. Further comprising a sixth step of taking out the laminate from the mold and peeling off the tape or film.
The method for manufacturing the structure according to claim 1. The sheet is a prepreg obtained by impregnating the reinforcing fibers with the thermosetting resin,
A method for manufacturing the structure according to claim 1. In the second step, while rotating the mandrel, a tape is wrapped around the laminate while applying a predetermined tension.
The manufacturing method of the structure according to any one of claims 1 to 3. In the second step, a tube made of a heat-shrinkable film is arranged around the laminate to heat the heat-shrinkable film,
The manufacturing method of the structure according to any one of claims 1 to 3. In the third step, the laminate is heated so that the degree of cure of the thermosetting resin is in the range of 30% to 90%.
The method for manufacturing the structure according to claim 1. In the fifth step, pressure is applied in the molding die so as to provide a space inside the laminate.
A method for manufacturing the structure according to any one of claims 1 to 6. In the fifth step, pressure is applied in the molding die so that no space is provided inside the laminate.
A method for manufacturing the structure according to any one of claims 1 to 6. Is formed of a thermosetting resin impregnated into reinforcing fibers, the outer and the first flat surface and a second planar surface has an outer surface, in a cross section perpendicular to the axis of the structure, from the first plane A structure in which a normal line extending in one direction and a normal line extending outward from the second plane are directed in different directions ,
Intersections of the first flat surface and the second planar surface has a curved surface curvature changes constant or gradually, the reinforcing fibers passing through the intersection is continuous without break it,
Structure. The structure is plate-shaped and has no space inside.
The structure according to claim 9. The structure has a tubular shape, is joined to a mounting member for connecting to another component, and has a concave or convex engaging portion that engages with the mounting member inside,
The structure according to claim 9. The outer surface of another member inserted inside the tubular thermosetting resin, the thermosetting resin is in close contact,
The structure according to claim 9. A plurality of sheets and/or tapes containing reinforcing fibers and an uncured thermosetting resin are wound around a mandrel to form a tubular laminate.
The entire circumference of the laminate is pressed with a tape or a film,
The laminate is heated to a state before the thermosetting resin is completely cured,
Extracting the mandrel from the laminate,
The laminated body wound with the tape or film is placed in a molding die and pressed, and the laminated body is formed by heating the laminated body until the thermosetting resin is completely cured.
Structure.