JP2020142408A - Frp composite molded article and method of producing the same - Google Patents

Abstract

To provide an FRP composite molded article configured simply and excellent in bond strength with a bond-target article (e.g., other FRP composite molded articles), and a method of producing the same.SOLUTION: An FRP composite molded article includes: an FRP cylinder extending in a longitudinal direction; and a metal cylinder provided on an inner peripheral surface of at least one edge part of the FRP cylinder in the longitudinal direction and formed with a screw part that is screwed with a screw part of a bond-target article. A method of producing the FRP composite molded article comprises: a step of winding plural layers of prepreg on an outer peripheral surface of the metal cylinder; a step of thermally curing the plural layers of prepreg and integrally molding the FRP cylinder on the outer peripheral surface of the metal cylinder; a step of cutting the metal cylinder and the FRP cylinder in the longitudinal direction; and a step of forming the screw part in a cut-out part of the metal cylinder, the screw part being screwed with the screw part of the bond-target article.SELECTED DRAWING: Figure 1

Description

The present invention relates to an FRP composite molded product and a method for producing the same.

Patent Document 1 describes a power transmission member having a cylindrical member made of fiber reinforced plastic (FRP) and a joint member. Male threads are formed on the outer peripheral surface of the boss portion formed on one end of the joint member, and female threads are formed on the inner peripheral surface of the fiber reinforced plastic (FRP) cylindrical member. By screwing the male and female threads, the cylindrical member made of fiber reinforced plastic (FRP) and the joint member are joined.

Further, Patent Document 1 describes that the joint member is provided with an adhesive storage portion for supplying an adhesive between the outer peripheral surface of the joint member and the inner peripheral surface of the fiber reinforced plastic (FRP) cylindrical member. Has been done. Further, Patent Document 1 describes that a metal core material is bonded to the inner peripheral surface of a cylindrical member made of fiber reinforced plastic (FRP).

JP-A-2010-107020

However, since the power transmission member of Patent Document 1 has a female thread formed on the inner peripheral surface of a cylindrical member made of fiber reinforced plastic (FRP), high precision is required for processing.

Further, the power transmission member of Patent Document 1 has a drawback that the bonding strength (for example, tensile strength) between the male screw of the joint member and the female screw of the cylindrical member made of fiber reinforced plastic (FRP) is insufficient. In order to make up for this drawback, an adhesive storage part is provided in the joint member, but processing the adhesive storage part in the joint member to store the adhesive makes manufacturing difficult, makes the structure complicated, and costs high. It leads to the conversion.

Further, in the power transmission member of Patent Document 1, a metal core material is bonded to the inner peripheral surface of the cylindrical member made of fiber reinforced plastic (FRP), but the inner peripheral surface of the cylindrical member made of fiber reinforced plastic (FRP) Of these, the bonding region of the metal core material corresponds to the non-forming region of the female thread. Therefore, there is no change in forming a female thread on the inner peripheral surface of the fiber reinforced plastic (FRP) cylindrical member, and the bond strength between the male thread of the joint member and the female thread of the fiber reinforced plastic (FRP) cylindrical member (for example, tensile strength). The drawback of insufficient strength) has not yet been eliminated.

The present invention has been made based on the above awareness of the problems, and is an FRP composite molded product having a simple structure and excellent bonding strength with a bonding object (for example, another FRP composite molded product) and its production. The purpose is to provide a method.

The FRP composite molded product of the present embodiment is provided at least on the inner peripheral surface of the FRP cylinder extending in the longitudinal direction and one end portion in the longitudinal direction of the FRP cylinder, and is screwed into the threaded portion of the object to be bonded. It is characterized by having a metal cylinder in which a is formed.

The metal cylinder may be provided on the inner peripheral surface of the entire longitudinal direction of the FRP cylinder.

The metal cylinder may be provided on the inner peripheral surface of one end or both ends of the FRP cylinder in the longitudinal direction.

The FRP cylinder may bite into the inner peripheral side to a radial position overlapping the metal cylinder in the intermediate portion in the longitudinal direction of the FRP cylinder in which the metal cylinder is not provided.

The FRP cylinder is obtained by winding a plurality of layers of prepreg around the outer peripheral surface of the metal cylinder and thermosetting the FRP cylinder, and the plurality of layers of prepreg is at least one of three layers close to the outer peripheral surface of the metal cylinder. May include a 0 ° layer prepreg whose fiber direction is parallel to the longitudinal direction of the FRP cylinder.

The plurality of layers of prepreg may include a rubber layer prepreg made of a rubber material.

When the radial length of the FRP cylinder is D1 and the radial length of the metal cylinder is D2, it is preferable that D1 / D2 <4 is satisfied, and 0.25 <D1 / D2 <4. It is more preferable to be satisfied.

Cut marks when cut from another FRP composite molded product may be formed on one end or both ends of the FRP composite molded product.

The method for manufacturing the FRP composite molded product of the present embodiment includes a step of winding a plurality of layers of prepreg around the outer peripheral surface of the metal cylinder, and heat-curing the multiple layers of prepreg to form an FRP cylinder on the outer peripheral surface of the metal cylinder. It includes a step of integrally forming, a step of cutting the metal cylinder and the FRP cylinder in the longitudinal direction, and a step of forming a threaded portion screwed into the threaded portion of the object to be coupled in the cut portion of the metal cylinder. It is characterized by that.

According to this embodiment, it is possible to provide an FRP composite molded product having a simple structure and excellent bonding strength with a bonding object (for example, another FRP composite molded product) and a method for producing the same.

It is a conceptual diagram which shows the joint part of the adjacent FRP composite molded article. It is a figure which shows the 1st example of the positional relationship between an FRP cylinder and a metal cylinder. It is a figure which shows the 2nd example of the positional relationship between an FRP cylinder and a metal cylinder. It is a figure which shows the 3rd example of the positional relationship between an FRP cylinder and a metal cylinder. It is a figure which shows an example of the laminated structure of the prepreg of a plurality of layers which constitute an FRP cylinder. It is a figure which shows another example of the laminated structure of the prepreg of a plurality of layers constituting an FRP cylinder. It is a figure which shows an example of the ratio of the length of the FRP cylinder and the metal cylinder in the radial direction. It is a figure which shows an example of the manufacturing process of the FRP composite molded article.

The FRP (Fiber Reinforced Plastics) composite molded product 1 according to the present embodiment will be described in detail with reference to FIGS. 1 to 8. The FRP composite molded product 1 can be applied to all technical fields now or in the future, but as a specific application, a drone frame, a robot arm, a jungle gym, or the like can be assumed. For example, the FRP composite molded product 1 can be made into a long member by joining adjacent FRP composite molded products 1 as "bonding objects". Further, the FRP composite molded product 1 can be bonded to the base of the other device as a "bonding object". Further, the FRP composite molded product 1 can also be applied to a coupling structure of a golf club shaft and a golf club head. For example, an FRP composite molded product 1 having a female threaded portion formed on the inner peripheral surface of an end portion is applied to a golf club shaft, and a "bonding object" having a male threaded portion formed on an outer peripheral surface of the end portion is applied to a golf club head. Then, the golf club shaft and the golf club head can be made removable (replaceable). Alternatively / in addition, the coupling structure according to the present embodiment can be applied in order to divide the golf club shaft in the longitudinal direction (axial direction) and connect the divided shafts. In this case, the length of the golf club shaft can be adjusted according to the length of each divided shaft and the number of connecting blocks (joining pieces).

FIG. 1 is a conceptual diagram showing a joint portion of adjacent FRP composite molded products 1X and 1Y. The FRP composite molded product 1X has an FRP cylinder 10X extending in the longitudinal direction and a metal cylinder 20X provided on the inner peripheral surface of the FRP cylinder 10X. The FRP composite molded product 1Y has an FRP cylinder 10Y extending in the longitudinal direction and a metal cylinder 20Y provided on the inner peripheral surface of the FRP cylinder 10Y. A female screw portion (screw portion) 21X is formed on the inner peripheral surface of one end portion (right end portion in FIG. 1) of the metal cylinder 20X, and the outer peripheral surface of one end portion (left end portion in FIG. 1) of the metal cylinder 20Y. Is formed with a male screw portion (screw portion) 21Y. By screwing the female screw portion 21X and the male screw portion 21Y, the adjacent FRP composite molded products 1X and 1Y are combined.

The male screw portion 21Y of the metal cylinder 20Y is configured as follows, for example. That is, on the inner peripheral surface of one end (left end in FIG. 1) of the metal cylinder 20Y, a female screw portion similar to the female screw portion 21X of the metal cylinder 20X is formed, and a male screw portion attachment is formed on the female screw portion. Is screwed. This male threaded portion attachment has a male threaded portion partitioned at an intermediate portion in the longitudinal direction (left-right direction in FIG. 1). Of the male threaded portions of the male threaded portion attachment, the right half of FIG. 1 is screwed into the female threaded portion of the inner peripheral surface of the metal cylinder 20Y, and the left half of FIG. 1 is the male threaded portion 21Y of the metal cylinder 20Y. It is exposed. That is, in the present embodiment, the male screw portion attachment is regarded as a part of the metal cylinder 20Y. There is a degree of freedom in how to configure the male screw portion 21Y of the metal cylinder 20Y, and various design changes are possible.

FIG. 2 is a diagram showing a first example of the positional relationship between the FRP cylinder 10 and the metal cylinder 20. In FIG. 2, the metal cylinder 20 is provided on the inner peripheral surface of the entire area of the FRP cylinder 10 in the longitudinal direction. When the FRP composite molded product 1 configured as shown in FIG. 2 is manufactured, the metal cylinder 20 is formed by winding a plurality of layers of prepregs around the outer peripheral surface of the metal cylinder 20 and then thermosetting the plurality of layers of prepregs. The FRP cylinder 10 is integrally molded on the outer peripheral surface.

FIG. 3 is a diagram showing a second example of the positional relationship between the FRP cylinder 10 and the metal cylinder 20. In FIG. 3, the metal cylinder 20 is provided on the inner peripheral surface of one end (right end in FIG. 3) of the FRP cylinder 10 in the longitudinal direction. When manufacturing the FRP composite molded product 1 configured as shown in FIG. 3, a core metal (not shown) having the same diameter as the metal cylinder 20 is abutted against the end surface (left end surface of FIG. 3) of the metal cylinder 20 to form a metal. After winding a plurality of layers of prepreg around the outer peripheral surfaces of the cylinder 20 and the core metal, the FRP cylinder 10 is integrally formed on the outer peripheral surface of the metal cylinder 20 by thermosetting the plurality of layers of prepreg. After that, the core metal is pulled out to the side opposite to the metal cylinder 20 (left side in FIG. 3) to remove it.

FIG. 4 is a diagram showing a third example of the positional relationship between the FRP cylinder 10 and the metal cylinder 20. In FIG. 4, metal cylinders 20 are provided on the inner peripheral surfaces of both ends (left end and right end in FIG. 3) of the FRP cylinder 10 in the longitudinal direction. Further, the FRP cylinder 10 bites into the inner peripheral side up to a radial position overlapping the metal cylinder 20 in the intermediate portion in the longitudinal direction of the FRP cylinder 10 in which the metal cylinder 20 is not provided. When manufacturing the FRP composite molded product 1 configured as shown in FIG. 4, the metal cylinder 20 is abutted against both end faces (left end face and right end face of FIG. 4) of the small diameter FRP cylinder prepared in advance, and the small diameter FRP cylinder is formed. After winding the plurality of layers of prepreg around the outer peripheral surface of the metal cylinder 20, the plurality of layers of prepreg are thermoset. Then, the FRP cylinder 10 is integrally formed on the outer peripheral surface of the metal cylinder 20, and the FRP cylinder 10 is integrated with the small-diameter FRP cylinder.

As shown in FIGS. 2 to 4, the metal cylinder 20 may be provided at least on the inner peripheral surface of one end of the FRP cylinder 10 in the longitudinal direction.

As described above, the FRP cylinder 10 is obtained by winding a plurality of layers of prepreg around the outer peripheral surface of the metal cylinder 20 and thermosetting the FRP cylinder 10. In the following, with reference to FIGS. 5A to 5F, a laminated structure of a plurality of layers of prepregs constituting the FRP cylinder 10 will be described. In FIGS. 5A-5F, order 1 indicates the innermost metal cylinder 20, and order 2-6 indicates a plurality of layers of prepreg. The smaller the order, the prepreg on the inner layer side closer to the outer peripheral surface of the metal cylinder 20, and the larger the order, the prepreg on the outer layer side farther from the outer peripheral surface of the metal cylinder 20. 5A to 5F exemplify a case where a prepreg in which carbon fibers are impregnated with an uncured thermosetting resin is used as the prepregs of a plurality of layers, but the fibers used are not limited to carbon fibers and are of other types. Reinforcing fiber can be used.

In FIG. 5A, 0 ° layer prepregs (hereinafter simply referred to as 0 ° layer prepregs) whose fiber directions are parallel to the longitudinal direction of the FRP cylinder 10 are arranged in order from the inner layer side close to the outer peripheral surface of the metal cylinder 20 to the outer layer side. Three layers (3 plies) are wound continuously, and one layer (1 ply) of 90 ° layer prepreg (hereinafter simply referred to as 90 ° layer prepreg) whose fiber direction is orthogonal to the longitudinal direction of the FRP cylinder 10 is wound at 0 °. One layer (1 ply) of layer prepreg is wound.

In FIG. 5B, the 0 ° layer prepreg is continuously wound in two layers (2 plies) and the 90 ° layer prepreg is wound in one layer (1 ply) in order from the inner layer side near the outer peripheral surface of the metal cylinder 20 to the outer layer side. The 0 ° layer prepreg is wound one layer (1 ply), and the 90 ° layer prepreg is wound one layer (1 ply).

In FIG. 5C, the 0 ° layer prepreg is wound by one layer (1 ply) and the 90 ° layer prepreg is wound by one layer (1 ply) in order from the inner layer side close to the outer peripheral surface of the metal cylinder 20 to the outer layer side. The 0 ° layer prepreg is wound one layer (1 ply), the 90 ° layer prepreg is wound one layer (1 ply), and the 0 ° layer prepreg is wound one layer (1 ply).

In FIG. 5D, the 90 ° layer prepreg is continuously wound in three layers (3 plies) and the 0 ° layer prepreg is wound in one layer (1 ply) in order from the inner layer side near the outer peripheral surface of the metal cylinder 20 to the outer layer side. It is wound and a 90 ° layer prepreg is wound in one layer (1 ply).

In FIG. 5E, the 90 ° layer prepreg is continuously wound in two layers (2 plies) and the 0 ° layer prepreg is wound in one layer (1 ply) in order from the inner layer side near the outer peripheral surface of the metal cylinder 20 to the outer layer side. The 90 ° layer prepreg is wound one layer (1 ply), and the 0 ° layer prepreg is wound one layer (1 ply).

In FIG. 5F, the 90 ° layer prepreg is wound by one layer (1 ply) and the 0 ° layer prepreg is wound by one layer (1 ply) in order from the inner layer side close to the outer peripheral surface of the metal cylinder 20 to the outer layer side. The 90 ° layer prepreg is wound one layer (1 ply), the 0 ° layer prepreg is wound one layer (1 ply), and the 90 ° layer prepreg is wound one layer (1 ply).

As shown in FIGS. 5A to 5C, 5E, and 5F, the multi-layer prepreg has at least one of the three layers near the outer peripheral surface of the metal cylinder 20, and the fiber direction is the longitudinal direction of the FRP cylinder 10. Includes parallel 0 ° layer prepregs. Thereby, the joint strength (for example, tensile strength) of the FRP cylinder 10 and the metal cylinder 20 can be improved.

As shown in FIGS. 5A-5C, the multi-layer prepreg includes a 0 ° layer prepreg located in one layer near the outer peripheral surface of the metal cylinder 20. As shown in FIGS. 5A and 5B, the multi-layer prepreg includes a continuous 0 ° layer prepreg over two layers near the outer peripheral surface of the metal cylinder 20. As shown in FIG. 5A, the multi-layer prepreg includes a continuous 0 ° layer prepreg over three layers near the outer peripheral surface of the metal cylinder 20. Thereby, the joint strength (for example, tensile strength) of the FRP cylinder 10 and the metal cylinder 20 can be further improved. The joint strength of FIG. 5A is the highest, the joint strength of FIG. 5B is the second highest, and the joint strength of FIG. 5C is the third highest.

6A to 6D are views showing another example of a laminated structure of a plurality of layers of prepregs constituting the FRP cylinder 10. 6A to 6D show, as a basic laminated structure of prepregs, 0 ° layer prepregs are continuously wound in three layers (3 plies) in order from the inner layer side close to the outer peripheral surface of the metal cylinder 20 toward the outer layer side. , 90 ° layer prepreg wound 1 layer (1 ply), 0 ° layer prepreg wound 1 layer (1 ply), 90 ° layer prepreg wound 1 layer (1 ply), 0 ° layer prepreg wound 1 layer (1 ply) winding, 90 ° layer prepreg is wound 1 layer (1 ply). On top of that, a rubber layer prepreg made of a rubber material is included in any part of the basic prepreg laminated structure. By providing the rubber layer prepreg, the vibration damping performance of the FRP cylinder 1 and thus the FRP composite molded product 1 can be improved.

In FIG. 6A, the rubber layer prepreg is provided between the outer peripheral surface of the metal cylinder 20 and the first layer (first ply) of the 0 ° layer prepreg (in order 2). In FIG. 6B, the rubber layer prepreg is provided between the first layer (first ply) and the second layer (second ply) (order 3) of the 0 ° layer prepreg. In FIG. 6C, the rubber layer prepreg is provided between the 90 ° layer prepreg in order 5 and the 0 ° layer prepreg in order 7 (order 6). In FIG. 6D, the rubber layer prepreg is provided between the 0 ° layer prepreg in order 6 and the 90 ° layer prepreg in order 8 (order 7).

7A and 7B are diagrams showing an example of the ratio of the radial lengths of the FRP cylinder 10 and the metal cylinder 20. When the radial length of the FRP cylinder 10 is D1 and the radial length of the metal cylinder 20 is D2, it is preferable that D1 / D2 <4 is satisfied, and 0.25 <D1 / D2 <4. It is more preferable to be satisfied. That is, the FRP cylinder 10 integrally molded on the outer peripheral surface of the metal cylinder 20 may be defective if it is too thick or too thin with respect to the metal cylinder 20.

When the FRP cylinder 10 becomes too thick (D1 / D2 ≧ 4) beyond the upper limit of the above conditional expression, the metal portion (metal cylinder 20) occupies most of the thickness, which is the original advantage of the FRP composite molded product 1. Is impaired. In addition, the anisotropy, which is a characteristic of the FRP composite molded product 1, is also impaired. When the FRP cylinder 10 becomes too thin (D1 / D2 ≦ 0.25) beyond the lower limit of the above conditional expression, the thickness and strength of the metal tube (metal cylinder 20) required for threading can be secured. It will disappear. By the way, FIG. 7A depicts a case corresponding to the upper limit of the above conditional expression (D1 / D2 = 4), and FIG. 7B shows a case corresponding to the lower limit of the above conditional expression (D1 / D2 = 0.25). I'm drawing.

A method for manufacturing the FRP composite molded product 1 will be described with reference to FIGS. 8A to 8D as appropriate.

<Prepreg winding process>
A plurality of layers of prepreg are wound around the outer peripheral surface of the metal cylinder 20. For the multi-layer prepreg, for example, the laminated structure of FIGS. 5A to 5F or 6A to 6D can be used.

<Thermosetting process>
The FRP cylinder 10 is integrally molded on the outer peripheral surface of the metal cylinder 20 by thermosetting the plurality of layers of prepreg. FIG. 8A shows an FRP composite molded product 1 which is an integrally molded product of the FRP cylinder 10 and the metal cylinder 20.

<Cutting process>
As shown in FIG. 8B, the FRP composite molded product 1 which is an integrally molded product of the FRP cylinder 10 and the metal cylinder 20 is cut in the longitudinal direction. Here, paying attention to one of the left and right FRP composite molded products 1 in FIG. 8B, one end or both ends of the FRP composite molded product 1 which is a cut portion is from the other (other) FRP composite molded product 1. Cutting marks are formed when cutting.

<Chamfering process>
As shown in FIG. 8C, at one end or both ends of the FRP composite molded product 1, the inner peripheral surface of the metal cylinder 20 is chamfered to form the chamfered portion 22.

<Screw part forming process>
As shown in FIG. 8D, at one end or both ends of the FRP composite molded product 1, the screw portion forming jig 30 is screwed into the inner peripheral surface of the metal cylinder 20 to form the female screw portion 21. That is, the threaded portion of the metal cylinder 20 is screwed into the threaded portion of the object to be joined (for example, the male threaded portion 21Y of the metal cylinder 20Y of the FRP composite molded product 1Y of FIG. 1) (for example, the FRP composite of FIG. 1). The female screw portion 21X) of the metal cylinder 20X of the molded product 1X is formed. In the threaded portion forming step, since the chamfered portion 22 is formed on the inner peripheral surface of the metal cylinder 20, the threaded portion forming jig 30 can be easily screwed into the inner peripheral surface of the metal cylinder 20.

The present inventor actually produced an FRP composite molded product 1 having a prepreg laminated structure of FIGS. 5A to 5F, and conducted a strength test (tensile strength test). The results are shown below. In the test, metal fittings were attached to both ends of the FRP composite molded product 1, and the joint strength between the metal (metal cylinder 20) and the FRP (FRP cylinder 10) was measured by pulling the metal fittings from both ends. A universal testing machine (model: 5582) manufactured by Instron was used as the testing machine, and the tensile test conditions were 5 mm / min. As a result, the strength between the metal (metal cylinder 20) and the FRP (FRP cylinder 10) is preferably that the innermost layer of the prepreg laminated structure is a prepreg with 0 °, and more preferably two layers (2) of 0 ° prepreg. It was found that when the amount is more than ply), high strength between the metal (metal cylinder 20) and the FRP (metal cylinder 10) can be expected. That is, among the FRP composite molded products 1 having the prepreg laminated structure of FIGS. 5A to 5F, FIG. 5A has the highest bonding strength, FIG. 5B has the second highest bonding strength, and the third It was shown in FIG. 5C that the joint strength was high.

As described above, the FRP composite molded product of the present embodiment is provided at least on the inner peripheral surface of the FRP cylinder extending in the longitudinal direction and one end portion in the longitudinal direction of the FRP cylinder, and is screwed into the threaded portion of the object to be bonded. It has a metal cylinder on which a threaded portion is formed. As a result, it is possible to realize an FRP composite molded product having a simple structure and excellent bonding strength with a bonding object (for example, another FRP composite molded product).

Since FRP products (for example, CFRP products) show high strength due to continuous fibers, once molded products cannot be replenished by post-processing. In addition, the limit value of each device (for example, the axial length for guaranteeing coaxiality and strength) is fixed, and a product exceeding that limit cannot be manufactured. In the FRP composite molded product of the present embodiment, a metal is incorporated and molded inside the FRP product formed into a cylindrical shape. The metal inside and the FRP have high adhesion, and the metal is located at the center of the cylindrical FRP. The length of the cylindrical FRP can be extended by screwing the metal in the center and connecting with the screws. Further, since the metal inside and the FRP have high adhesion, the product can have high strength in the longitudinal direction, the tensile direction, the circumferential direction, and the bending direction.

1 1X 1Y FRP composite molded product (Fiber Reinforced Plastics) (object to be combined)
10 10X 10Y FRP cylinder 20 20X 20Y Metal cylinder 21 21X Female thread part (thread part)
21Y male screw part (screw part)
22 Chamfering part 30 Threaded part forming jig

Claims (9)

FRP cylinder extending in the longitudinal direction and
A metal cylinder provided on the inner peripheral surface of one end of the FRP cylinder in the longitudinal direction and having a threaded portion screwed into the threaded portion of the object to be coupled.
An FRP composite molded product characterized by having. The metal cylinder is provided on the inner peripheral surface of the entire longitudinal direction of the FRP cylinder.
The FRP composite molded product according to claim 1, characterized in that. The metal cylinder is provided on the inner peripheral surface of one end or both ends of the FRP cylinder in the longitudinal direction.
The FRP composite molded product according to claim 1, characterized in that. The FRP cylinder bites into the inner peripheral side to a radial position overlapping the metal cylinder in the intermediate portion in the longitudinal direction of the FRP cylinder in which the metal cylinder is not provided.
The FRP composite molded product according to claim 3, characterized in that. The FRP cylinder is obtained by winding a plurality of layers of prepreg around the outer peripheral surface of the metal cylinder and thermosetting the FRP cylinder.
The plurality of layers of the prepreg include, in at least one of the three layers near the outer peripheral surface of the metal cylinder, a 0 ° layer prepreg whose fiber direction is parallel to the longitudinal direction of the FRP cylinder.
The FRP composite molded product according to any one of claims 1 to 4, characterized in that. The multi-layer prepreg includes a rubber layer prepreg made of a rubber material.
The FRP composite molded product according to claim 5, characterized in that. When the radial length of the FRP cylinder is D1 and the radial length of the metal cylinder is D2, D1 / D2 <4 is satisfied.
The FRP composite molded product according to any one of claims 1 to 6, characterized in that. At one end or both ends of the FRP composite molded product, cutting marks when cut from another FRP composite molded product are formed.
The FRP composite molded product according to any one of claims 1 to 7, characterized in that. A step of winding multiple layers of prepreg around the outer peripheral surface of a metal cylinder,
A step of thermosetting the plurality of layers of prepreg to integrally form an FRP cylinder on the outer peripheral surface of the metal cylinder.
A step of cutting the metal cylinder and the FRP cylinder in the longitudinal direction,
The step of forming a threaded portion screwed into the threaded portion of the object to be bonded in the cut portion of the metal cylinder
A method for producing an FRP composite molded product, which comprises.