JPH07214678A - Connecting pipe made of fiber reinforced resin and production thereof - Google Patents

Abstract

PURPOSE:To simply, inexpensibly and efficiently produce a connected pipe made of a fiber reinforced resin sufficient in connection strength and high sealability. CONSTITUTION:A connection pipe made of a fiber reinforced resin having a fiber layer formed along the shape of a screw in a braid like state is produced by braiding fibers on the outer periphery of a mandrel having a screw shape provided to the outer periphery thereof and impregnating the braided fibers with a resin to cure the impregnated fibers and subsequently pulling out the mandrel. A plurality of pipes 10, 11 made of a fiber reinforced resin having a braided fiber layer formed along the shape of a screw in a braided state are integrally connected by threading the connection screw parts 13, 14 thereof with the connection pipe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe for interconnecting pipes made of fiber reinforced plastic and a method for producing the pipe.

[0002]

2. Description of the Related Art Fiber-reinforced plastics containing fibers such as glass fibers, carbon fibers and aramid fibers are widely used in order to utilize the lightness of plastic products and further improve the strength. A thermosetting resin or a thermoplastic resin is used as the plastic in which the fibers are mixed, and as a method for mixing the fibers, the fibers are shredded and mixed in a melt of these resins, and injection or extrusion molding is performed. Or
A method in which fibers are knitted and woven and arranged in a mold and impregnated and coated with a resin is adopted.

On the other hand, as a fiber reinforced plastic molded product, it is used for various purposes. One of them is a fiber reinforced plastic molded product, which is used as a pipe for supplying high-pressure fluid with high pressure resistance. , Or used as a structural material such as scaffolding for construction instead of metal pipes,
Due to its light weight and high strength, its application range is expanding.

[0004]

When using the above-mentioned fiber reinforced plastic pipe, it is necessary to use a plurality of pipes connected to each other both as a fluid supply pipe and a structural material pipe. . When connecting such pipes, both ends of the pipes are butted and melt-bonded or bonded with an adhesive, or a connecting tool that can fit the connecting pipes from both sides is used. It is also practiced to join both pipes by joining at.

However, the strength may not be sufficient depending on this joining state only by joining both ends of the pipe by abutting them, and there is a risk of breaking the pipe for high-pressure liquid or the structural material during use. Also,
In the case of joining by using a connecting tool, since the two pipes and the connecting portion are joined at two points, the possibility of lowering the strength at the joining portion is further increased. It becomes difficult to secure the sealing property at the joint portion of.

On the other hand, it is also practiced to provide a screw on the pipe itself and screw male and female screws on both ends of the pipe, or to screw both pipes to a connector having screws on both ends. However, although the fiber-reinforced plastic pipe itself is strong against bending, compression, pulling, shearing, etc., when the thread is cut on the surface of the pipe, the fiber is cut, and there is almost no difference from the strength of conventional plastics. Therefore, it is not possible to obtain sufficient strength only by connecting the screws formed on the surface of the pipe to each other, and it is extremely dangerous in use for the high-pressure fluid supply or the structural material that the strength of this joint is weak. Further, providing a screw on the pipe increases the number of steps, and requires a lot of time and cost.

Therefore, the present invention provides a fiber-reinforced resin joint pipe that is simple and inexpensive, has sufficient joint strength, and has a good sealing property, and is an efficient method for producing a fiber-reinforced resin joint pipe. It is a thing.

[0008]

In order to achieve the above object, the present invention provides a fiber reinforced resin joint having a thread portion for joining a pipe with a fiber layer formed into a braid shape along the shape of the thread. A fiber-reinforced resin-bonded pipe for producing a bonded pipe by forming fibers into a mandrel having a screw shape on the outer circumference with a braiding machine, impregnating the fibers with a resin, and then curing the fiber, and then removing the mandrel. In the manufacturing method of, further, by screwing a plurality of fiber-reinforced resin pipes having a fiber layer formed into a braided shape along the shape of the screw to each other, to screw the mutual screws. This is a jointed and integrated fiber-reinforced resin pipe.

[0009]

In the fiber-reinforced resin-bonded pipe according to the present invention, since the thread portion for joining the pipe has the fiber layer formed into a braid shape along the shape of the screw, the strength of the thread portion is extremely high. It is strong, and when used, the threaded portions of such two pipes are screwed together to form a solidly integrated pipe. Furthermore, since a plurality of fiber-reinforced resin pipes having a fiber layer formed in a braided shape along the shape of the screw are joined and integrated with each other by screwing the screws together, The two pipes are joined by simply screwing them together without using a nut type pipe.

[0010]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a manufacturing process of a pipe used in the present invention. As shown in FIG. 2B, a mandrel 3 having a projecting portion 1 at one end and a screw-shaped portion 2 as shown in FIG. Then, it is covered with a braided fiber 4 composed of fibers such as glass fiber and carbon fiber. This braided fiber can be composed by braiding on a rod-shaped mandrel 3 by a braiding machine.

At this time, as shown in FIG. 2, the pitch P of the screw to be composed is 10 times or more the apparent width of the fiber, and the diameter D of the mandrel is the difference W between the thread radius and the valley radius of the screw. It is preferably 20 to 30 times or more of the above, because the fiber can be formed without breaking. At this time, the curvature R of the screw part of the mandrel in which the fibers are assembled is 3R or more, 5R or more in the case of ceramic fibers, and 1R or less in the case of aramid fibers.

Next, as shown in FIG. 3C, a mandrel 3 covered with the above-mentioned composition fiber 4 is placed between the lower mold 6 and the upper mold 7, and the inner circumference of the upper mold and the lower mold and the outer circumference of the mandrel 3 are arranged. The space 8 formed in 1 is filled with resin by injection or extrusion. On the inner circumferences of the upper mold 7 and the lower mold 6, screw-shaped portions having the same shape as the screw-shaped portion 2 of the mandrel 3 are formed,
The ends of the upper shape 7 and the lower shape 6 are in close contact with the outer circumference of the protruding portion 1 of the mandrel 3. The resin filled in the space 8 penetrates through the voids of the composition fiber coated on the outer periphery of the mandrel 3 and reaches the outer peripheral surface of the mandrel 3, and becomes a resin-formed product including the integrated fiber layer.

When the resin in the space 8 is a thermosetting resin,
After the resin is cured by performing an operation such as putting it in a heating furnace, the upper shape 7 and the lower shape 6 are removed, the outer periphery of the pipe as a resin molded product is gripped, and the protruding portion 1 of the mandrel 3 is fixed to the screw shape portion 2. The mandrel 3 is rotated in the direction of moving to the protruding portion 1 side in accordance with the screw shape of FIG. 3 and the mandrel 3 is extracted from the molded pipe to obtain a fiber-reinforced resin pipe 10 as shown in FIG. .

The pipe 11 and the nut type pipe 12 shown in FIG. 2 are molded by the same means as described above. The threaded portion 13 of the pipe 11 has a reverse thread to the threaded portion 14 of the pipe 10. Further, the left half of the nut type pipe 12 in the drawing is formed with a screw shape in a direction to be screwed with the screw shape portion 14 of the pipe 10, and the right half is with a screw shape in a direction to be screwed with the screw shape portion 13 of the pipe 11. It is formed. As a result, the nut-type pipe 12 has a left-handed and a right-handed screw with the center position as a boundary. Therefore, at the time of molding the nut type pipe 12, the mandrel can be divided into right and left parts, and the above-mentioned screws in opposite directions are formed on each mandrel. Rotate to and pull out.

When joining the pipes 13 and 14, each of the pipes 13 and 14 is provided with an opening 15 at both ends of the nut type pipe 12.
When the nut type pipe 12 is brought into contact with 16 and is rotated in the screwing direction, the screw-shaped portion 17 on the right side of the nut-shaped pipe 12 in the drawing and the screw-shaped portion 13 of the pipe 12 are screwed together to form the screw-shaped portion 14 on the left side. Finally, as shown in FIG. 3, both ends of both pipes 13 and 14 come into contact with each other at the central portion of the nut-type pipe 12 so that the screw-shaped portion 18 of the pipe 12 is screwed. Accordingly, the ends of both pipes are pressed against each other.
When joining the two pipes using the nut type pipe 12, a thermoplastic resin, a thermosetting resin, or each pipe is preliminarily provided on the outer periphery of the thread-shaped portions 13 and 14 of the pipes 10 and 11 and the inner periphery of the nut type pipe 12. By applying an adhesive suitable for the material and joining the two pipes as described above, the two pipes are firmly fixed. Further, when this pipe is used for the flow of the pressure fluid, a packing such as rubber may be interposed between the ends of both pipes so as to be fastened and fixed.

In manufacturing the pipe in the above embodiment, when the mandrel is pulled out after the resin of the pipe is cured,
Although FIG. 1 shows an example of pulling out to the right in the figure, when the outer diameter of the threaded portion is smaller than the outer diameter of the pipe, it is also possible to pull out from the other end side of the mandrel not shown.

Although the thread shape of the thread shape portion can be arbitrarily selected, if the pitch of this thread shape is made large, the height of the screw thread is made low, and the number of threads is made small, the fiber layer is included. The screw-shaped part can be easily manufactured.

In the above embodiment, an example in which both pipes are joined by using a nut type pipe has been shown, but as shown in FIG. 4, a diametrically enlarged portion 21 is formed at the end of one pipe 20,
The enlarged diameter portion 21 is provided with a thread-shaped portion 22 mainly composed of an inner thread, and the thread-shaped portion 24 at the end of the pipe 23 on the other side is screwed into the thread-shaped portion 22 of the pipe 20 on the one side. You may.

With this structure, both pipes are joined by simply screwing them together without using a nut type pipe. Also in this case, as in the case of the above-described embodiment, an adhesive may be applied to the screw-engaged portions of both screw-shaped portions, or a packing may be interposed.

The pipes manufactured as described above are used for water supply, high-pressure fluid, building structural materials, aviation, space industry,
It can be widely used in fields requiring lightweight and strong members such as ultra-high-speed vehicles, solar cars, automobiles, and vehicles such as bicycles.

[0021]

As described above, according to the present invention, since the screw portion itself to which the pipe is joined is made of the fiber reinforced resin having the composition fiber layer, the strength of the screw is extremely strong, and the strong joining is possible. Therefore, it can be safely used even when a high-pressure fluid is flown, or when it is used in a portion requiring high strength such as a scaffold for construction. In addition, upon connection, they can be joined simply by screwing, they can be joined easily without using any other special auxiliary member, and the sealing performance is improved by the strong tightening force.

Further, by forming fibers on the outer periphery of a mandrel having a screw shape on the outer periphery with a braiding machine, impregnating the fibers with a resin, and then curing the resin, and by removing the mandrel, a joint pipe is manufactured. It is possible to integrally and continuously manufacture a joint pipe having a screw shape.

Further, a plurality of fiber-reinforced resin pipes having a fiber layer formed into a braid shape along the shape of the screw are joined to the joining screw portion by screwing the screws together to be integrated. So, without using a nut type pipe,
The two pipes can be joined by simply screwing them together.

[Brief description of drawings]

FIG. 1 is a diagram showing a pipe manufacturing process according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state before joining pipes according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a state after joining copper pipes.

FIG. 4 is a cross-sectional view showing a state after joining pipes according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Projection part 2 Screw shape part 3 Mandrel 4 Composition fiber 6 Lower mold 7 Upper mold 8 Space 10 Pipe 11 Pipe 12 Nut type pipe 13 Screw shape part 14 Screw shape part 15 Opening 16 Opening 17 Screw shape part 18 Screw shape part 21 Expansion Diameter part 21 22 Screw shape part 22 24 Screw shape part 24

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location D04C 1/06 F16L 9/12 15/00 // B29K 105: 08 B29L 23:00 31:24

Claims (3)

[Claims] 1. A joint pipe made of fiber reinforced resin, wherein the joint thread portion of the pipe has a fiber layer formed into a braid shape along the shape of the screw. 2. A joined pipe is manufactured by forming fibers on the outer periphery of a mandrel having a screw shape on the outer periphery by a braiding machine, impregnating the fibers with a resin, and then curing, and pulling out the mandrel. A method for manufacturing a joined pipe made of fiber reinforced resin. 3. A plurality of fiber-reinforced resin pipes having a fiber layer formed into a braided shape along the shape of the screw are joined to the joining screw portion by screwing the screws together to be integrated. A fiber-reinforced resin pipe characterized in that