JP6820737B2 - Manufacturing method of FRP fastening structure and FRP fastening structure - Google Patents

Description

The present invention relates to a method for manufacturing a fastening structure of a structure made of a fiber reinforced plastic (hereinafter referred to as FRP) material.

In recent years, FRP has been applied in a wide range of fields by taking advantage of its light weight, high strength and high rigidity. Conventionally, FRP has been used for space and communication applications where light weight and high rigidity are required, such as satellite housing structures and antenna reflectors and radomes, but in recent years it has been mainly used for aircraft and automobiles. It is also being used for large structures and moving bodies. By applying lightweight, high-strength, and highly rigid FRP to a structure that was conventionally made of metal, the structure can be made lighter and energy saving and portability can be improved.

Regarding the material and molding method, in space and communication applications, an intermediate material called prepreg, which is pre-impregnated with resin between fibers, is used, and a method called autoclave molding method, which heats and pressurizes with a pressure cooker, is often used. However, there is a problem that the material / molding cost increases, and it is required to reduce the material / molding cost as the application expands.

Here, a vacuum impregnation molding method has been proposed as a low-cost molding method for FRP that replaces the autoclave molding method. The vacuum impregnation molding method is a molding method in which a fiber cloth made of woven fibers is impregnated with a liquid resin by atmospheric pressure. As a specific procedure, a fiber cloth is laminated on the molding die, a flow media for diffusing the resin in the in-plane direction and a peel ply having releasability are laminated on the molding die in the order of the peel ply flow media, and the surroundings. Place a sealant to maintain airtightness, install an injection / suction port, and cover the whole with a vacuum film to seal it. After connecting the suction port to a vacuum pump and vacuum sucking the inside of the vacuum film, the injection port is connected to a resin tank to impregnate the resin with atmospheric pressure, and the resin is cured to obtain a molded product. The vacuum impregnation molding method does not require large-scale equipment such as an autoclave or a strong molding mold, and therefore can be molded at low cost.

When manufacturing a large structure, it is necessary to fasten and assemble a plurality of members in order to form a complicated structure. In the case of conventional metal structures, welding or mechanical fastening such as bolts and nuts has often been used. Considering the case of an FRP structure, welding cannot be performed unlike metal, so mechanical fastening or adhesive fastening using an adhesive can be considered. Further, when the FRP resin is composed of a thermoplastic resin, fastening by welding the resin is also conceivable. Of these fastening methods, adhesion or welding has the advantage of being able to disperse and fasten a large area without defects such as fastening holes, but process control is more complicated than mechanical fastening, and at the assembly site. There is a drawback that the workability is inferior.

In view of the above-mentioned drawbacks, mechanical fastening is often used as a fastening method for FRP at present. In the mechanical fastening method, a fastening component such as a bolt is inserted into the fastening hole, and the fastening structure is maintained by the frictional force between the fastening component and the object to be fastened. The frictional force is generated by the axial force of the fastening parts, but when the axial force is lowered, the frictional force is also lowered, and the fastening structure may be destroyed.

Since FRP is a material in which a laminated body of fibers is integrated with a resin, the resin is not oriented in the thickness direction, and the resin alone is responsible for the axial force at the fastening portion. If the axial force continues to act on the FRP for a long period of time, the axial force decreases due to the creep of the resin, which may lead to the destruction of the fastening structure. When applying mechanical fastening to an FRP fastening structure, a fastening structure that prevents the above-mentioned destruction is required.

As a fastening structure for preventing the fastening structure from being destroyed by resin creep, there is a method of inserting a collar with flanges from both sides into a fastening hole made in an FRP member (see, for example, Patent Document 1). With this method, by holding the axial force with the collar, the axial force hardly acts on the FRP member, and creep in the thickness direction can be prevented. The thickness of the FRP member is more likely to vary than that of the metal member, but in Patent Document 1, it is possible to absorb the variation in the thickness of the FRP member by carving a screw groove in the collar.

Japanese Unexamined Patent Publication No. 2006-329336 Japanese Unexamined Patent Publication No. 2014-141048

In one of the fastening methods described in Patent Document 1, a flanged collar having a thread groove is inserted from both sides of the fastening hole so as to screw the collars together. Adjust the meshing length of the screw to fix the distance between the flanges according to the FRP member, and insert the bolt into the collar to fasten it to the other member. By adjusting the screw part, the collar can be fixed without gaps or rattling regardless of the thickness variation of the FRP member, and by holding the axial force of the bolt with the collar, creep in the thickness direction of the FRP member is prevented. Can be done.

However, in Patent Document 1, in order to form a thread groove on the collar, it is necessary to make the thickness of the collar at least the depth of the thread groove thick in order to secure the strength of the collar itself. As the thickness of the collar increases, the size of the hole formed in the FRP member also increases, and the length of the surplus portion from the hole wall surface to the end of the FRP member becomes shorter. When the length of the surplus portion is shortened, an in-plane load acts on the FRP member, and when a surface pressure load acts on the hole wall surface via the fastening part, the fastening structure is broken due to the breakage of the surplus portion. This may reduce the strength of the FRP member itself. In order to prevent breakage of the surplus portion, it is necessary to increase the thickness of the FRP member, which leads to an increase in the weight of the member itself.

In order to fix the insert parts such as collars without rattling without the need for an adjustment mechanism such as a screw groove and regardless of the thickness variation of the FRP parts, the insert parts are embedded in advance at the time of molding the FRP parts. (See, for example, Patent Document 2).

In one of the fiber-reinforced composite materials described in Patent Document 2, a fastening member having a flange portion is embedded and integrated at the time of molding. Since the fastening member is embedded in advance, an adjustment mechanism is not required, and by holding the axial force of the bolt with the fastening member, creep in the thickness direction of the FRP member can be prevented.

However, in the fiber-reinforced composite material described in Patent Document 2, when a pulling load in the bolt axial force direction acts on the fiber-reinforced composite material via the fastening member, the layers of the fiber-reinforced composite material start from the flange portion of the fastening member. Peeling may occur, and the strength of the FRP member itself is reduced.

As described above, in the prior art, there is a problem that the strength of the FRP member itself is lowered by inserting the insert component.

The present invention has been made in view of the above problems, and in a method for manufacturing an FRP fastening structure formed by a vacuum impregnation molding method and a resin in the FRP fastening structure at a lower cost than the autoclave molding method. It is an object of the present invention to provide a method for manufacturing an FRP fastening structure and an FRP fastening structure that prevents the fastening structure from being destroyed by creeping and preventing the strength of the FRP member itself from being lowered due to the insertion of insert parts.

In order to achieve the above object, the method for manufacturing the FRP fastening structure according to the present invention includes a first step of fitting the outer flanged collar into the positioning groove of the molding die and the outer side of the outer flanged collar on the molding die. A second step of laminating the fiber woven fabric constituting the FRP molded body, a third step of inserting the inner flanged collar inside the outer flanged collar and embedding it in the fastening hole of the fiber woven fabric, and on the fiber woven fabric. The fourth step of laminating the resin impregnated auxiliary material on the portion excluding the inner flanged collar and sucking it by vacuum pressure, and under the resin impregnated auxiliary material, the liquid resin is applied to the fiber woven fabric and the outer flanged collar. The molded product obtained in the fifth step of impregnating the product with the inner flanged collar and the fifth step after curing the liquid resin is removed from the molding die and the resin impregnated auxiliary material is peeled off. This includes a sixth step of obtaining the FRP molded product.

Further, in order to achieve the above object, the FRP fastening structure according to the present invention includes an outer flanged collar and an inner flanged collar that is inserted inside the outer flanged collar and embedded in the fastening hole of the FRP molded body. The fiber woven fabric laminate formed on the outside of the outer flanged collar and constituting the FRP molded body is provided between the fiber woven laminate, the outer flanged collar, and the inner flanged collar. A single liquid resin cured product is formed.

According to the present invention, the inner flanged collar is inserted inside the outer flanged collar and embedded in the fastening hole of the fiber woven fabric constituting the FRP molded body, and the fiber woven fabric laminate is laminated on the outside of the outer flanged collar. A liquid resin is formed between the fiber woven fabric, the collar with the outer flange, and the collar with the inner flange to form an FRP molded body.

In this way, by embedding and molding the collar with the outer flange and the collar with the inner flange in the FRP molded body, it is possible to prevent the fastening structure from being destroyed by the creep of the resin, and the FRP itself due to the insertion of the insert component. It is possible to provide a method for manufacturing an FRP fastening structure and an FRP fastening structure that prevent a decrease in strength.

It is sectional drawing which shows the manufacturing method of the FRP fastening structure which concerns on this invention, and the FRP fastening structure in Embodiment 1 of the FRP fastening structure. It is sectional drawing which extracted the flanged collar in the FRP structure shown in FIG. 1, (A) is the sectional view of the outer flanged collar, (B) is the sectional view of the inner flanged collar. FIG. 5 is a cross-sectional view showing a state in which an FRP member according to the first embodiment of the present invention is fastened to a mating member with bolts, nuts, and washers. FIG. 5 is a cross-sectional view showing a state in which a collar with an outer flange is arranged on a molding die in the color arrangement step according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing a state in which a fiber woven fabric is laminated on a molding die in the state shown in FIG. FIG. 5 is a cross-sectional view showing a state in which the inner flanged collar is inserted into the outer flanged collar in the state shown in FIG. FIG. 6 is a cross-sectional view showing a state in which a peel ply and a flow media are laminated on a fiber woven fabric in the state shown in FIG. FIG. 7 is a cross-sectional view showing a state in which the entire surface is covered with a vacuum film and vacuum suction is performed in the state shown in FIG. FIG. 5 is a cross-sectional view showing a state in which the resin is filled by vacuum impregnation molding in the state shown in FIG. 8 and the curing of the resin is completed. It is sectional drawing which shows the state which the FRP molded body was demolded in the state shown in FIG. It is sectional drawing which shows the FRP member which trimmed the end part of the FRP molded body in the state shown in FIG. It is sectional drawing which shows the manufacturing method of the FRP fastening structure which concerns on this invention, and the FRP fastening structure in Embodiment 2 of the FRP fastening structure. FIG. 12 is a schematic cross-sectional view showing a molding die according to the second embodiment of the present invention shown in FIG. FIG. 12 is a cross-sectional view showing a state in which the entire surface is covered with a vacuum film and vacuum suction is performed in the state shown in FIG. FIG. 5 is a cross-sectional view showing a state in which an inner flanged collar and a hole filling pin are inserted into an outer flanged collar in the method for manufacturing an FRP fastening structure according to the present invention and the collar inserting step in the third embodiment of the FRP fastening structure. FIG. 15 is a cross-sectional view showing a state in which the entire surface is covered with a vacuum film and vacuum suction is performed in the state shown in FIG. It is a flowchart which shows the manufacturing process of the FRP fastening structure by Embodiment 1 of this invention. It is a perspective view which shows the FRP member in Example 1 in Embodiment 1 of this invention. It is a flowchart which shows the manufacturing process of the FRP member in the comparative example 1 of this invention. It is sectional drawing which shows the FRP fastening structure by the comparative example 1 shown in FIG.

Hereinafter, a method for manufacturing a fastening structure according to the present invention will be described with reference to the drawings according to a preferred embodiment. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

Embodiment 1.
First, the FRP fastening structure 1 in the first embodiment will be described with reference to FIGS. 1 to 3.
As shown in FIG. 1, the FRP fastening structure 1 is a part of the FRP member 2, and is composed of an FRP molded body 3, a collar 4 with an outer flange, and a collar 5 with an inner flange. The FRP member 2 is a member that uses FRP formed as an FRP molded body 3 as a main material and is fastened to another member via an FRP fastening structure 1 to form a specific product structure. The collar 4 with an outer flange and the collar 5 with an inner flange are embedded in the fastening hole 30 of the FRP molded body 3. The FRP molded body 3 and the collar 4 with the outer flange are the upper surface 4b of the molding surface 3a of the FRP molded body 3 and the flange portion 4-1 of the collar 4 with the outer flange (see FIG. 2 (A)), and the FRP molded body. The hole wall surface of the fastening hole 30 of No. 3-the outer surface 4c of the collar portion 4-2 of the collar 4 with the outer flange is adhered.

The FRP molded body 3 and the collar 5 with an inner flange are bonded to the atmospheric side surface 3b of the FRP molded body 3 and the lower surface 5b of the flange portion 5-1 of the collar 5 with an inner flange (see FIG. 2B). The outer flanged collar 4 and the inner flanged collar 5 are the end surface 4d of the collar portion 4-2 (see FIG. 2 (A)) of the outer flanged collar 4, and the lower surface of the flange portion 5-1 of the inner flanged collar 5. The inner surface 4e of the collar portion 4-2 of the outer flanged collar 4 and the outer surface 5c of the collar portion 5-2 of the inner flanged collar 5 are bonded to each other via an adhesive (not shown) described later. ..

The FRP molded body 3, the collar 4 with the outer flange, and the collar 5 with the inner flange are integrally molded by the procedure described later with the respective surfaces in contact with each other, and the residual stress in the thickness direction is formed on the FRP molded body 3. Does not occur.

The end surface 5d of the collar portion 5-2 of the inner flanged collar 5 must not be below the lower surface 4a of the flange portion 4-1 of the outer flanged collar 4 in FIG. That is, the height h of the inner flanged collar 5 shown in FIG. 2B is the height H of the outer flanged collar 4 shown in FIG. 2A and the thickness of the flange portion 5-1 of the inner flanged collar 5. It must not be greater than the sum with t. In other words, if the end surface 5d of the collar portion 5-2 of the inner flanged collar 5 is below the lower surface 4a of the outer flanged collar flange 4 in FIG. 1, the washer 9 and the inner flanged collar 5 described later interfere with each other. Therefore, the end surface 5d of the collar portion 5-2 of the inner flanged collar 5 must be above the lower surface 4a of the flange portion 4-1 of the outer flanged collar 4 in FIG.

The thickness of the collar portion 4-2 of the collar 4 with the outer flange is determined by the magnitude of the fastening load acting on the FRP fastening structure 1. The thickness of the collar portion 5-2 of the collar 5 with the inner flange may be the minimum thickness necessary to prevent the collar 5 with the inner flange and the collar 4 with the outer flange from being misaligned. The inner diameter of the collar portion 5-2 of the collar 5 with an inner flange is determined by the diameter of a fastening part such as a bolt 7 (see FIG. 3) inserted into the FRP fastening structure 1.

The material of the collar 4 with the outer flange and the collar 5 with the inner flange may be any material that can support the axial force of the bolt 7, and is not particularly limited. However, from the viewpoint of fastening with the frictional force with the bolt 7, nut 8, and washer 9, it is a metal of the same type as the bolt 7, nut 8, and washer 9, and is surface-hardened to improve wear resistance. It is desirable to have. Further, although it depends on the usage environment, when the reinforcing fiber of the FRP molded body 3 is carbon fiber, it may be better to avoid the aluminum alloy from the viewpoint of electrolytic corrosion.

The fastening hole 30 of the FRP molded body 3 is circular, and as shown in FIG. 1, the diameter of the fastening hole 30 of the FRP molded body 3 is d. The FRP molded body 3 is provided so as to be separated from the end face 3d by a distance b. The relationship between d and b is preferably such that the size of b is at least 0.5 times or more of d, and more preferably 1.25 times or more. If the size of b is too small with respect to d, when a load is applied in the direction perpendicular to the paper surface of FIG. 1, the surplus portion from the end face of the FRP molded body 3 to the wall surface of the fastening hole 30 of the FRP molded body 3 The FRP molded body 3 may break.

Further, although not shown in FIG. 1, a plurality of FRP fastening structures 1 may be provided for one FRP member 2. At this time, the distance between the FRP fastening structures 1, that is, the distance between the centers of the fastening holes 30 of the FRP molded body 3 is preferably at least twice or more the diameter d of the fastening holes 30 of the FRP molded body 3. It is more suitable if it is 3.5 times or more.

As shown in FIG. 3, the FRP member 2 is fastened to the mating member 6 via a bolt 7, a nut 8, and a washer 9. The threaded portion of the bolt 7 penetrates the mating member 6 and the FRP fastening structure 1 and is screwed with the threaded portion of the nut 8 to generate an axial force. Due to this axial force, a frictional force is generated between the mating member 6 and the FRP fastening structure 1, and the mating member 6 is integrally fastened. In FIG. 3, the axial force is borne by the flange portion 5-1 of the collar 5 with the inner flange and the collar portion 4-2 of the collar 4 with the outer flange. Since the axial force hardly acts on the FRP molded body 3, creep does not occur in the FRP molded body 3, and it is possible to prevent a decrease in the axial force.

The mating member 6 is fastened so as to be in contact with the flange portion 5-1 of the collar 5 with an inner flange of the FRP fastening structure 1, and the head of the bolt 7 is on the mating member 6 side and the nut 8 is on the FRP member 2 side. , Each positional relationship may be reversed. Further, in FIG. 3, washers 9 are used on both sides of the FRP member 2 and the mating member 6, but the washer 9 on the FRP member 2 side can be replaced by the outer flanged collar 4 or the inner flanged collar 5. Therefore, it does not have to be used.

Next, a method of manufacturing the FRP fastening structure 1 will be described with reference to FIGS. 4 to 11.
As shown in FIG. 4, the molding die 10 has a positioning groove 11. The molding die 10 is subjected to degreasing and mold release treatment before molding. In the color arranging step, the flange portion 4-1 of the outer flanged collar 4 is arranged in the positioning groove 11. By positioning the outer flanged collar 4 in the positioning groove 11, it is possible to prevent the outer flanged collar 4 from being displaced in a later process.

After arranging the outer flanged collar 4 in the positioning groove 11 of the molding die 10, the fiber woven fabric 12 is laminated on the molding die 10 as shown in FIG. The collar 4 with an outer flange is inserted into the hole in which the fiber woven fabric 12 is cut out in advance, that is, the fastening hole 30 of the FRP molded body 3 or the eye of the fiber woven fabric 12. If it is inserted into the eyes of the fiber woven fabric 12, the fibers are not broken and the strength of the FRP molded body 3 can be prevented from decreasing. However, when the outer diameter of the collar portion 4-2 of the collar 4 with the outer flange is large, it is easier to stack the fiber woven fabric 12 by cutting it out in advance.

Examples of the fiber type of the fiber woven fabric 12 include carbon fiber, glass fiber, and other organic fibers, and are not particularly limited. Examples of the weaving structure of the fiber woven fabric 12 include plain weave, satin weave, twill weave, non-crimp fabric, and the like, and are not particularly limited.

In FIG. 5, the number of laminated fibers of the fiber woven fabric 12 is 12, but the number of laminated fibers is not particularly limited. However, the fiber woven fabric 12 is pressed against the molding die 10 by atmospheric pressure in a later step, and has a predetermined molding thickness. It is desirable that the height H of the collar portion 4-2 of the outer flanged collar 4 is substantially the same as the molding thickness. Therefore, when the fiber woven fabric 12 is laminated, the outermost fiber is as shown in FIG. The woven fabric 12 is above the end surface 4d of the collar portion 4-2 of the outer flanged collar 4.

After laminating the fiber woven fabric 12 on the molding die 10, the inner flanged collar 5 is inserted into the outer flanged collar 4 as shown in FIG. As described above, when the laminating of the fiber woven fabric 12 is completed, the outermost layer of the fiber woven fabric 12 is above the end face 4d of the collar portion 4-2 of the outer flanged collar 4, so that the collar portion 4- of the outer flanged collar 4 The end surface 4d of 2 and the lower surface 5b of the flange portion 5-1 of the collar 5 with an inner flange are separated from each other.

After inserting the inner flanged collar 5 into the outer flanged collar 4, the peel ply 13 and the flow media 14 are laminated on the fiber woven fabric 12 as shown in FIG. The peel ply 13 is an auxiliary material for peeling the flow media 14 from the FRP molded body 3 after resin impregnation and curing. The flow media 14 is an auxiliary material for assisting the resin impregnation of the fiber woven fabric 12. The peel ply 13 and the flow media 14 are previously cut out in contact with the inner flanged collar 5. As a result, resin filling inside the collar 5 with an inner flange is prevented.

After laminating the peel ply 13 and the flow media 14, the whole is covered with the vacuum film 15 and vacuum suction is performed as shown in FIG. The peel ply 13, the flow media 14, and the vacuum film 15 described later constitute a resin-impregnated auxiliary material. At this time, the fiber woven fabric 12 is pressed against the molding die 10 by the atmospheric pressure, and the inner flanged collar 5 is pushed into the outer flanged collar 4. At this time, the end surface 4d of the collar portion 4-2 of the outer flanged collar 4 and the lower surface 5b of the flange portion 5-1 of the inner flanged collar 5 are in contact with each other to determine the thickness of the FRP fastening structure 1.

Next, the liquid resin is impregnated into the fiber woven fabric 12 by vacuum pressure. In the step of covering with the vacuum film 15 described above, a resin injection port and a suction port are provided, and the injection port is connected to the resin tank and the suction port is connected to the vacuum pump. After the entire fiber woven fabric 12 is impregnated with the liquid resin, the resin injection and vacuum suction are stopped, and the resin is cured at room temperature or by heating. In the resin injection step, the liquid resin is impregnated between the fiber woven fabric 12, the collar 4 with the outer flange, and the collar 5 with the inner flange, and the three parties are adhered and fixed by curing, thereby integrally as shown in FIG. It is molded.

The type of the liquid resin may be an epoxy resin, a vinyl ester resin, a cyanate ester resin, a polyester resin, or the like, and is not particularly limited as long as it has a low viscosity at room temperature. The viscosity at room temperature is preferably 500 mPa · s or less.

The surfaces of the collars 4 with the outer flange and the collar 5 with the inner flange, that is, the outer surface 4c of the collar portion, the end surface 4d of the collar portion, the inner surface 4e of the collar portion, the outer surface 5c of the collar portion, the end surface 5d of the collar portion, and If the inner surface 5e of the collar portion is subjected to a polishing treatment in advance, the adhesive strength can be improved when the FRP molded body 3 and the collars 4 and 5 with flanges are integrally molded.

Further, before inserting the collar 5 with the inner flange, a liquid resin is applied to the inner surface 4e of the collar portion and the end surface 4d of the collar portion of the collar 4 with the outer flange, and the outer surface 5c of the collar portion and the lower surface 5b of the flange portion of the collar 5 with the inner flange. If this is done, it is possible to prevent the occurrence of resin-impregnated portions between the collars and to ensure adhesion.

After confirming the curing of the resin, the FRP molded body 3 is removed from the molding die 10 as shown in FIG. 10, and the peel ply 13 and the flow media 14 are peeled off. Since the FRP molded body 3 immediately after demolding has burrs and the like at the ends, the FRP member 2 including the FRP fastening structure 1 can be obtained by post-processing to a predetermined size as shown in FIG.

Through the above steps, the FRP fastening structure 1 composed of the FRP molded body 3, the collar 4 with the outer flange, and the collar 5 with the inner flange can be manufactured. In the above vacuum suction step, the collar 5 with the inner flange is pushed into the collar 4 with the outer flange, so that the end surface 4d of the collar portion 4-2 of the collar 4 with the outer flange and the flange portion 5-of the collar 5 with the inner flange The lower surface 5b of 1 is in contact with each other, and the thickness of the FRP fastening structure 1 is determined.

That is, since the thickness of the FRP fastening structure 1 is determined by the dimensions of the outer flanged collar 4 and the inner flanged collar 5 without being affected by the variation due to the vacuum impregnation molding, the thickness variation adjusting mechanism becomes unnecessary. Therefore, the thickness of the collar portions 4-2 and 5-2 can be reduced by the amount of the unnecessary thickness variation adjusting mechanism, so that the diameter of the fastening hole 30 of the FRP molded body 3 can be reduced. It is possible to prevent a decrease in the strength of the FRP molded body 3.

The thinness of the collar portions 4-2 and 5-2 can vary depending on the conditions of the member to be applied (dimensions, working load, durability), so as a guide, the diameter is the same as the inner diameter of the outer flanged collar 4. It is about the screw groove depth of bolts and nuts.

Embodiment 2.
Compared with the method for manufacturing the fastening structure in the first embodiment, the method for manufacturing the fastening structure in the second embodiment has the outer flanged collar 4, the inner flanged collar 5, and the collar positioning groove 11 of the molding die 10. The shapes of the above are different, and the outer peripheral portions of the flange portions 4-1 and 5-1 and the positioning groove 11 are tapered. However, the shapes are the same except for the shapes of the collar 4 with the outer flange, the collar 5 with the inner flange, and the collar positioning groove 11 of the molding die 10, and the same reference numerals are given to the same parts, and the description thereof will be omitted.

In the cross-sectional view of the FRP fastening structure 1 according to the second embodiment shown in FIG. 12, as shown in the drawing, the outer peripheral portions of the flange portions 4-1 and 5-1 of the outer flanged collar 4 and the inner flanged collar 5 are tapered. It has a shape. By making the outer peripheral portion of the flange portion tapered, the weight of the collars 4 and 5 can be reduced, and the stress concentration when an external force is applied at the portion where the outer peripheral portion of the flange and the FRP are in contact is reduced, and the FRP fastening structure 1 The strength of the can be improved.

FIG. 13 shows a cross-sectional view of the molding die 10 according to the second embodiment. As shown in FIG. 13, the positioning groove 11 of the molding die 10 has a shape that fits with the shape of the flange portion 4-1 of the collar 4 with an outer flange, and the outer peripheral portion has a tapered shape. By fitting the shape of the flange portion 4-1 of the outer flanged collar 4 and the shape of the positioning groove 11 of the molding die 10 into a fitting shape, it is possible to prevent the collars 4 and 5 from being displaced during molding.

After arranging the outer flanged collar 4 on the molding die 10, the fiber woven fabric 12 is laminated, the inner flanged collar 5 is inserted, and the peel ply 13 and the flow media 14 are laminated in the same procedure as in the first embodiment. Then, the whole is covered with the vacuum film 15 and vacuum sucked.

FIG. 14 shows a cross-sectional view of a state in which the entire surface is covered with a vacuum film 15 and vacuum sucked in the vacuum impregnation molding step according to the second embodiment. As shown in the figure, since the outer peripheral portion of the flange portion 5-1 of the collar 5 with the inner flange is tapered, the vacuum film 15 can be easily brought into close contact with the upper surface of the flange portion 5-1 without wrinkles or tension. You can. The FRP fastening structure 1 can be obtained by covering the whole with a vacuum film 15 and vacuum suctioning, and then performing vacuum impregnation molding in the same procedure as in the first embodiment.

Embodiment 3.
Compared with the method for manufacturing the fastening structure in the above-described first and second embodiments, the method for manufacturing the fastening structure in the third embodiment is a hole filling pin at the same time as the step of inserting the inner flanged collar 5 into the outer flanged collar 4. The difference is that 16 is inserted. In addition, as shown in FIG. 16, the peel ply 13 and the flow media 14 are also laminated on the upper portion of the flanged collar / hole filling pin 16 in the auxiliary material laminating step. However, the same applies except for the existence of the hole filling pin 16 and the stacking range of the auxiliary materials, and the same reference numerals are added to the same parts, and the description thereof will be omitted.

In the method for manufacturing the fastening structure in the third embodiment, the collar is arranged on the molding die 10 and the fiber woven fabric 12 is laminated in the same procedure as in the first and second embodiments described above. As shown in FIGS. 15 and 16, the filling of the resin inside the inner flanged collar 5 can be prevented by inserting the hole filling pin 16 further inside the inner flanged collar 5. The hole filling pin 16 has been subjected to a mold release process in advance so that it can be removed after the FRP molded body 3 is removed from the mold.

FIG. 16 shows a cross-sectional view of a state in which the peel ply 13 and the flow media 14 are laminated, and then the whole is covered with a vacuum film 15 and vacuum-sucked. As shown in the figure, the peel ply 13 and the flow media 14 are laminated up to the inner flanged collar 5 and the upper part of the hole filling pin 16.

In the same step in the above-described first embodiment, in order to prevent resin filling inside the collar 5 with an inner flange, it was necessary to hollow out the peel ply 13 and the flow media 14 at the collar insertion position, but the hole filling pin 16 was used. By inserting the collar 5, it is possible to prevent the resin filling inside the collar 5 with the inner flange even if the insertion positions of the collars 4 and 5 are not hollowed out.

As a result, the molding process can be further simplified and the productivity can be improved. Further, if the height of the hole filling pin 16 is set to the same value as the sum of the height of the collar portion 4-2 of the outer flanged collar 4 and the thickness of the flange portion 5-1 of the inner flanged collar 5, the inner flanged collar Since the upper surface of the flange portion 5-1 of 5 and the upper end surface of the hole filling pin 16 are flush with each other and there is no gap between the peel ply 13 and the upper end surface of the hole filling pin 16, the peel ply 13, the flow media 14, and the vacuum film 15 are wrinkled. It can be easily laminated without tension.

The FRP fastening structure 1 can be obtained by covering the whole with a vacuum film 15 and vacuum suctioning, and then performing vacuum impregnation molding in the same procedure as in the above-described first and second embodiments. In addition, in FIGS. 15 and 16, the shapes of the collar 4 with the outer flange, the collar 5 with the inner flange, and the collar positioning groove 11 of the molding die 10 were the same as those of the second embodiment. Even if the shape is the same as that of the first embodiment, the same effect can be obtained.

<Example>
Example 1.
Hereinafter, as Example 1 of the method for manufacturing the FRP member 2 according to the first embodiment, the flowchart shown in FIG. 17 and the perspective view of the FRP member 2 shown in FIG. 18 will be described.

First, the FRP member 2 shown in FIG. 18 is a member having a U-shaped constant cross section, and has three FRP fastening structures 1 at each of the U-shaped bottoms at both ends, for a total of six places. The dimensions are, for example, 200 mm in width, 100 mm in height, 1000 mm in length, and 7 mm in thickness as a whole.

Further, the shape of the FRP fastening structure 1 is the same as that of the collar 4 with the outer flange and the collar 5 with the inner flange shown in FIG. 2, and the respective dimensions are, for example, H = h = 10 mm and T = t = 3 mm. is there.

Further, as the fiber woven fabric 12 shown in FIG. 5 and the like, 35 carbon fiber cloth materials (for example, T700 carbon fiber plain weave cloth material manufactured by Toray Industries, Inc.) cut out to a width of 500 mm and a length of 1100 mm were laminated. The fiber woven fabric 12 was cut out at six holes having a diameter of 18 mm, which would later become fastening holes 30.
Next, as shown in FIG. 4, six outer flanged collars 4 are arranged in the positioning groove 11 provided at a predetermined position of the U-shaped molding die 10 that has undergone the mold release process (FIG. 17). First step).

Next, as shown in FIG. 5, the fiber woven fabric 12 is laminated on the molding die 10 so that the collar 4 with the outer flange is inserted into the hole cut out in advance (the second step). At this time, the end portion of the fiber woven fabric 12 is fixed to the molding die 10 with a temporary fixing tape.
Then, as shown in FIG. 6, after laminating all the fiber woven fabrics 12, the inner flanged collar 5 is inserted into the outer flanged collar 4 (the third step).

Next, as shown in FIG. 7, the peel ply 13 and the flow media 14 having cut out 6 holes in advance are laminated on the fiber woven fabric 12 (the fourth step). The ends of the peel ply 13 and the flow media 14 are fixed to the molding die 10 with temporary fixing tape in the same manner as the fiber woven fabric 12.

Next, as shown in FIG. 8, the injection port and the suction port are linearly installed so as to face each other along the longitudinal direction of the end of the fiber woven fabric 12, and the whole is covered with the vacuum film 15. Further, the suction port is connected to the vacuum pump with the injection port closed, and vacuum suction is performed (the fourth step).
As a result, the fiber woven fabric 12 is pressed against the molding die 10 by the atmospheric pressure, and the inner flanged collar 5 is pushed into the outer flanged collar 4.

Next, as shown in FIG. 9, the injection port is connected to the resin layer, and the injection port is opened to open a liquid resin (for example, made by Japan U-Pica, epoxy acrylate resin Neopol 8197 (100 parts by weight), peroxide 328E (for example). 1 part by weight) and a mixed resin of cobalt octylate (0.2 parts by weight)) are impregnated into the fiber woven fabric 12 by vacuum pressure (the fifth step).
The liquid resin is impregnated in the width direction from the injection port to the suction port. After the entire fiber woven fabric 12 is impregnated with the liquid resin, the resin injection and vacuum suction are stopped, and the resin is cured at room temperature.

After confirming the curing of the resin, as shown in FIG. 10, the FRP molded body 3 is removed from the molding die 10 and the peel ply 13 and the flow media 14 are peeled off (the sixth step).
Then, as shown in FIG. 11, burrs and the like at the three ends of the FRP molded body are removed by processing to obtain a U-shaped FRP member 2 including six FRP fastening structures 1.

<Comparison example>
Comparative example 1.
Hereinafter, as a comparative example with respect to the first embodiment, the flowchart showing the manufacturing process of the FRP member shown in FIG. 19 and the FRP member 2 shown in FIG. 20 will be described.
In addition, this Comparative Example 1 is different from Example 1 in the FRP fastening structure and the manufacturing method thereof. However, the structure is the same except for the FRP fastening structure and the manufacturing method thereof, and the same reference numerals are added to the same parts, and the description thereof will be omitted. Further, as the reference numerals, those of the first embodiment are used in the same manner as in the first embodiment.

The shape and dimensions of the FRP member 2 in Comparative Example 1 are the same as those of the FRP member 2 in Example 1 shown in FIG. Similar to the first embodiment, the U-shaped bottoms at both ends have three FRP fastening structures 1 in total.

First, six flanged collars 4 and 5 having the same shape and dimensions as in the first embodiment are prepared.
Next, as the fiber woven fabric 12, 35 carbon fiber cloth materials (for example, T700 carbon fiber plain weave cloth material manufactured by Toray Industries, Inc.) cut out to a width of 500 mm and a length of 1100 mm are prepared. However, in this Comparative Example 1, no hole was cut out in the fiber woven fabric 12.

Next, the fiber woven fabric 12 is laminated on the U-shaped molding die 10 that has undergone the mold release treatment (first step in FIG. 19).
However, the molding die 10 in Comparative Example 1 is not provided with the positioning groove 11. After laminating the fiber woven fabric 12 on the molding die 10, the end portion of the fiber woven fabric 12 is fixed to the molding die 10 with a temporary fixing tape.

Next, the peel ply 13 and the flow media 14 are laminated on the fiber woven fabric 12 (second step). However, holes are not cut out in the peel ply 13 and the flow media 14 in Comparative Example 1. The ends of the peel ply 13 and the flow media 14 are fixed to the molding die 10 with temporary fixing tape in the same manner as the fiber woven fabric 12.

Next, along the longitudinal direction of the end of the fiber woven fabric 12, the injection port and the suction port are linearly installed so as to face each other, and the whole is covered with the vacuum film 15. Further, the suction port is connected to the vacuum pump with the injection port closed, and vacuum suction is performed (the second step).
As a result, the fiber woven fabric 12 is pressed against the molding die 10 by the atmospheric pressure.

Next, the injection port is connected to the resin layer, and the injection port is opened to open the liquid resin (made by Japan U-Pica, epoxy acrylate resin Neopol 8197 (100 parts by weight), peroxide 328E (1 part by weight), cobalt octylate (1 part by weight). (0.2 parts by weight) of the mixed resin) is impregnated into the fiber woven fabric 12 by vacuum pressure (the third step).
The liquid resin is impregnated in the width direction from the injection port to the suction port. After the entire fiber woven fabric 12 is impregnated with the liquid resin, the resin injection and vacuum suction are stopped, and the resin is cured at room temperature.

After confirming the curing of the resin, the FRP molded body 3 is removed from the molding die 10 and the peel ply 13 and the flow media 14 are peeled off (the fourth step).
The burrs and the like at the three ends of the FRP molded body are removed by processing, and six holes for embedding the color are machined at predetermined positions (the fifth step).

Next, as shown in FIG. 20, the adhesive 17 (two-component epoxy adhesive AV138 / HV998 manufactured by Nagase ChemteX) was applied to the outer flanged collar 4, the inner flanged collar 5, and the wall surface of the machined hole. The outer flanged collar 4 is inserted from one of the holes and the inner flanged collar 5 is inserted from the other so as to be combined with each other and bonded (sixth step). Then, the adhesive is cured at room temperature to obtain a U-shaped FRP member 2 including six FRP fastening structures 1.

That is, in this Comparative Example 1, as shown in FIG. 20, after molding the FRP molded body 3, a hole is formed to be a fastening hole 30, and flanged collars 4 and 5 are inserted into the hole and the adhesive 17 is used. Due to the adhesion, a step is generated by the adhesive 17 between the outer peripheral portion of the flange and the FRP molded body 3.
In the FRP fastening structure 1 in the first embodiment, since the FRP molded body 3 is molded and the flanged collar is bonded at the same time, no adhesive is required and no step is generated.

In the manufacturing method according to Comparative Example 1, when the molding thickness of the FRP molded body 3 varies, between the outer flanged collar 4 and the inner flanged collar 5, or between the flanged collars 4 and 5 and the FRP molded body 3. An excessive adhesive layer 17 may be formed between the flanged collars 4 and 5, and the effect of holding the axial force may not be obtained.

1 FRP fastening structure, 2 FRP member, 3 FRP molded body, 3a FRP molded body molding surface, 3b FRP molded body atmospheric side surface, 3c FRP molded inner surface, 4 outer flange collar, 4-1 outer flange collar Flange part, 4-2 Collage part with outer flange, 4a Lower surface of flange part with outer flange, 4b Upper surface of flange part with outer flange, 4c Collar part with outer flange, outer surface, 4d Collage with outer flange End face of the collar part, 4e Inner surface of the collar part of the outer flanged collar 4, 5 Inner flanged collar, 5-1 Inner flanged collar flanged part, 5-2 Inner flanged collar collared part, 5a Inner flanged collar Upper surface of flange, 5b Lower surface of flange with inner flange, 5c Outer surface of collar with inner flange, 5d End surface of collar with inner flange, 5e Inner surface of collar with inner flange, 6 mating member, 7 Bolts, 8 nuts, 9 washer, 10 molds, 11 positioning grooves, 12 fiber woven fabrics, 13 peel plies, 14 flow media, 15 vacuum films, 16 fill pins, 30 fastening holes.

Claims (12)

The first step of fitting the collar with the outer flange into the positioning groove of the molding mold,
The second step of laminating the fiber woven fabric constituting the FRP molded body on the outer side of the outer flanged collar on the molding die,
A third step of inserting the inner flanged collar inside the outer flanged collar and embedding it in the fastening hole of the fiber woven fabric.
A fourth step of laminating a resin-impregnated auxiliary material on the fiber woven fabric excluding the collar with the inner flange and sucking it by vacuum pressure.
Under the resin impregnation auxiliary material, a fifth step of impregnating the liquid resin between the fiber woven fabric, the outer flanged collar, and the inner flanged collar,
An FRP fastening structure including a sixth step of removing the molded product obtained in the fifth step after curing of the liquid resin from the molding mold and peeling off the resin impregnated auxiliary material to obtain the FRP molded product. Manufacturing method. The first aspect of claim 1, wherein a step of applying a cured liquid resin to the inner surface of the collar portion of the outer flanged collar and the outer surface of the collar portion of the inner flanged collar between the second step and the third step is included. FRP fastening structure manufacturing method. The method for manufacturing an FRP fastening structure according to claim 1 or 2, which comprises a step of preliminarily polishing the surfaces of the collars with outer flanges and the collars with inner flanges before the first step. .. The method for manufacturing an FRP fastening structure according to any one of claims 1 to 3, wherein the flange portion of the collar with an outer flange and the outer peripheral portion of the flange portion of the collar with an inner flange are tapered. The method for manufacturing an FRP fastening structure according to any one of claims 1 to 4, wherein the third step includes a step of inserting a hole filling pin inside the collar portion of the collar with an inner flange. The method for manufacturing an FRP fastening structure according to claim 5, wherein the fourth step includes a step of laminating the resin impregnated auxiliary material on the flange portion of the collar with an inner flange and the hole filling pin. The method for manufacturing an FRP fastening structure according to claim 5 or 6, wherein the height of the hole filling pin is equal to the sum of the height of the collar portion of the outer flanged collar and the thickness of the flange portion of the inner flanged collar. The method for manufacturing an FRP fastening structure according to any one of claims 1 to 7, further comprising a seventh step of post-processing the FRP molded product obtained in the sixth step to a set size. The method for manufacturing an FRP fastening structure according to claim 1, 2, 3, or 6, wherein the resin impregnated auxiliary material includes a peel ply, a flow media, and a vacuum film. Collar with outer flange and
An inner flanged collar that is inserted inside the outer flanged collar and embedded in the fastening hole of the FRP molded body,
It is provided with a laminate of fiber woven fabrics formed on the outside of the collar with an outer flange and constituting the FRP molded body.
An FRP fastening structure in which a single liquid resin cured product is formed between the laminated body of the fiber woven fabric, the collar with the outer flange, and the collar with the inner flange. The FRP fastening structure according to claim 10, wherein the surfaces of the collars with outer flanges and the collars with inner flanges are pre-polished. The FRP fastening structure according to claim 10, wherein the flange portion of the collar with an outer flange and the outer peripheral portion of the flange portion of the collar with an inner flange are tapered.

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