JP2004270781A - Manufacturing method for fiber-reinforced-plastic tube with joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method capable of manufacturing a fiber-reinforced-plastic (FRP) tube with a joint having high strength and stable quality and reducing manufacturing costs. <P>SOLUTION: A core tube 4 being longer than the FRP tube 1 is horizontally connected with a rotary shaft of a rotary driving device 7, a steel male screw joint tube 2 and a female screw joint tube 3 are inserted into the core tube 4, a release agent is applied on the surface of the core tube 4 between both screw joint tubes 2 and 3, and then, a glass fiber sheet 1b is wound up on a thin-walled section 2b of the male screw joint tube 2 and a thin-walled section 3b of the female screw joint tube 3 and on the surface of the core tube 4 located between them. Then, the resin is impregnated into the wound glass fiber sheet 1b while unsaturated polyester resin 1a is abstracted from an abstracting nozzle 8. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to the manufacture of an FRP pipe with a joint having a joint part such as a connection thread (male thread, female thread), a fitting joint, a flange joint, etc. at the pipe end of an FRP pipe made of FRP (glass fiber reinforced plastic). The present invention relates to a technique for manufacturing a FRP tube so that the strength and characteristics of the FRP pipe are not impaired by a threaded joint.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, FRP pipes provided with a threaded joint at a pipe end have been widely manufactured. These are used when connecting the FRP pipe to make it longer and longer by screwing it together with a screw joint. The threaded joint is used for connection with another member.
The method of manufacturing the FRP pipe with a threaded joint includes a method of forming a screw by threading the pipe end of the FRP pipe after forming the FRP pipe, and a method of forming a threaded portion 11a on the pipe end of the FRP pipe 10 as shown in FIG. The joint pipe 11 made of steel or the like having 11b is joined by an adhesive.
In the former manufacturing method, the glass fiber of the FRP tube is cut at the time of threading, and the tube end strength of the FRP tube tends to decrease. In the latter manufacturing method, the bonding between the joint pipe and the FRP pipe by the adhesive is apt to vary, and the bonding strength is insufficient. Furthermore, in order to make the thickness of the joint between the joint pipe and the FRP pipe the same as the thickness of the FRP pipe, the end of the FRP pipe must be thinned or tapered so as to reduce the strength of the pipe end. In addition, the number of processing steps was also required.
Also, the other fitting joints and flange joints are fixed by the same joining method as the latter method, and have the same problem as the latter.
As described above, the conventional method of manufacturing an FRP pipe with a threaded joint has insufficient strength and has variations, it is difficult to obtain stable quality, and the cost tends to be increased due to the number of steps.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a method of manufacturing a FRP pipe with a joint which solves the conventional problems and has high strength, stable quality and reduced manufacturing cost.
[0004]
[Means for Solving the Problems]
The configuration of the present invention that has solved such a problem includes:
1) At both ends of the FRP tube forming position of the core tube for forming an FRP tube, a joint tube in which a joint portion and a thin portion provided with irregularities on the outer peripheral surface are provided on opposite sides is fitted in a direction in which the thin portions face each other. The core pipe surface between the two pipe joints is covered with a release agent or a release tape, and the opposite thin part and the upper surface of the core pipe between them are coated with a reinforcing fiber sheet or a reinforcing fiber tape, and the thermosetting Resin impregnation, the impregnated resin cures, and the FRP tube forming and the fitting tube are integrated to produce a FRP tube with a joint by integrating the joint tube. 2) FRP tube forming of a core tube for FRP tube molding At both ends of the position, a male threaded joint pipe with male threads and a thin part with irregularities on the outer peripheral surface are provided on opposite sides, and a female thread part and a thin parts with irregularities on the outer peripheral face are provided on opposite sides. The thin-walled part faces the female threaded joint pipe With a release agent or a release tape on the surface of the core tube between the male screw joint tube and the female screw joint tube, and a reinforcing fiber sheet or a reinforcing fiber tape on the opposing thin portion and the upper surface of the core tube between them. A method of manufacturing a FRP pipe with a joint by manufacturing a FRP pipe with a threaded joint by forming the FRP pipe and integrating the male-female threaded pipe with the molding of the FRP pipe and curing of the impregnated resin. 3) At the end of the FRP tube forming position of the core tube for forming the FRP tube, a threaded portion and a threaded joint tube provided with a thin-walled portion having irregularities on the outer peripheral surface on opposite sides are fitted to each other, and the surface of the core tube is fitted. A release agent or a release tape is coated on the core tube surface and the upper surface of the thin-walled portion of the threaded joint tube is coated with a reinforcing fiber sheet or a reinforcing fiber tape and impregnated with a thermosetting resin, and the impregnated resin is cured. Molding of FRP pipe and male-female thread joint 4) A method of manufacturing an FRP pipe with a joint, in which an FRP pipe with a threaded joint is manufactured by integrating the above, 4) The method of manufacturing an FRP pipe with a joint according to 1) above, wherein the joint is a detachable fitting joint. The method for producing an FRP pipe with a joint according to the above 1), which is a flange joint connected by bolts 6) The method for producing an FRP pipe with a joint according to any of the above 1) to 5), wherein the material of the reinforcing fiber sheet is glass fiber It is in.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
The material of the joint part of the present invention such as a male thread joint pipe, a female thread joint pipe, a thread joint pipe, a fitting joint, and a flange joint may be any of steel, aluminum, titanium, plastic, and ceramic. Use materials.
FIG. 5 shows a structural example in which the joint of the present invention is a fitting joint or a flange joint. The joint shown in FIG. 5A is an example of a metal fitting joint 22 or 23 having a tubular shape. 22a and 23a are thin portions having irregularities on the outer peripheral surface, and 22b and 23b are gradually thinned to form a gradient. This is the fitted surface. The joint shown in FIG. 5 (b) is an example of bolted flange joints 24, 25, which have flanges 24a, 25a at the tip of a cylindrical body, and which penetrate a bolt 26 connecting the flanges 24a, 25a. It has holes 24b and 25b, and has thin portions 24c and 25c having irregularities on the outer peripheral surface on the FRP side.
A typical example of the FRP resin of the present invention is a thermosetting resin such as an unsaturated polyester resin or an epoxy resin.
The glass fiber sheet of the present invention may be knitted in a net shape, a helical shape, or the like, and may be in a linear shape.
The FRP pipe with a threaded joint manufactured by the present invention includes the FRP pipe of claim 2 in which both ends of the pipe are provided with a threaded joint, and the FRP pipe of claim 3 in which a threaded joint is provided only at one end of the pipe.
The impregnation of the thermosetting resin of the present invention into the reinforcing fiber sheet or tape may be performed after winding the sheet or tape, or may be performed by attaching the resin to the sheet or tape when winding the sheet or tape. It may be a method.
[0006]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The present embodiment is an example of manufacturing an FRP pipe with a threaded joint used for a boring rod used for underground excavation. The FRP pipe uses a glass fiber sheet woven in a net shape as a reinforcing material, and an unsaturated polyester as a resin. A resin is used, and the male and female threaded joints are examples made of steel.
[0007]
FIG. 1 is a longitudinal sectional view of an FRP pipe with a threaded joint manufactured by the manufacturing method of the embodiment.
FIG. 2 is an explanatory diagram illustrating a threaded connection state of the FRP pipe with a threaded joint manufactured by the manufacturing method of the embodiment.
3 and 4 are explanatory views showing the manufacturing steps of the embodiment.
[0008]
In the drawing, 1 is an FRP pipe with a threaded joint manufactured by the manufacturing method of the embodiment, 1a is an unsaturated polyester resin of FRP resin, 1b is a glass fiber sheet woven in a net shape, 2 is a steel male screwed joint pipe Reference numeral 2a denotes a male thread portion of the male threaded joint tube, 2b denotes a thin portion having irregularities on the outer surface, 3 denotes a steel female threaded joint tube, 3a denotes a female threaded portion of the same female threaded joint tube, and 3b denotes irregularities on the outer surface. Thin portion, 4 is a core tube for FRP molding having a diameter of 65 mm, called a mandrel, 4 m, 5 and 6 are sheet fixing devices for fixing a glass fiber sheet, 7 is a rotation driving device for the core tube 4, and 8 is an unsaturated polyester resin. Extraction nozzle.
[0009]
In this embodiment, first, the core tube 4 longer than the length of the FRP tube to be manufactured is horizontally connected to the rotation shaft of the rotation driving device 7. Next, the male screw joint tube 2 and the female screw joint tube 3 made of steel are fitted into the core tube 4, a release agent is applied to the surface of the core tube 4 between the two screw joint tubes 2, 3, and then the glass fiber The sheet 1b is wound around the thin portion 2b of the male screw joint tube 2, the thin portion 3b of the female screw joint tube 3, and the surface of the core tube 4 therebetween. Thereafter, while extracting the unsaturated polyester resin 1a from the extraction nozzle 8, the wound glass fiber sheet 1b is impregnated with the resin. The outer diameter of the FRP on the outer periphery of the thin portions 2b and 3b is set to be the same as the outer diameter of the FRP on the outer periphery of the core tube 4.
[0010]
Thereafter, when the resin is heated and cured and dried, the unsaturated polyester resin 1a is cured while enclosing the glass fiber sheet 1b to form an FRP tube. The FRP pipe is also integrally formed on the outer periphery of the thin portion 2b of the male screw joint 2 and the outer periphery of the thin portion 3b of the female screw joint 3. The thin portions 2b, 3b and the FRP on the outer periphery are firmly bonded to each other by the adhesive force of the unsaturated polyester resin 1a and the unevenness of the thin portions 2b, 3b. In addition, the outer FRP has sufficient strength because of the glass fiber sheet 1b.
[0011]
A tensile test of the FRP pipe with a threaded joint manufactured in this way revealed that it can withstand 2.5 to 5 times the tensile load as compared with a conventional FRP pipe with a threaded joint of adhesive bonding.
[0012]
In this embodiment, threaded joint pipes (male threaded joint pipe 2 and female threaded joint pipe 3) are provided at both ends of the FRP pipe. However, one of the threaded joint pipes is omitted and a threaded joint pipe is attached to only one end. An FRP tube with a joint can be manufactured in the same procedure as in the above embodiment.
[0013]
The manufacture of a joint using a fitting joint other than a screw joint and a flange joint is the same as that of the present embodiment, and the joined state is shown in FIG.
[0014]
【The invention's effect】
As described above, according to the present invention, when the reinforcing fiber is wound around the outer periphery of the thin-walled portion of the joint tube and the outer periphery of the core tube, impregnated with resin and cured to form the FRP, Is fixed to the FRP, the FRP can have the original strength of the FRP without a decrease in strength due to the post-cutting processing, and the bonding of the joint pipe is also made of the thermosetting resin of the FRP. Since it is tightened, the joining can be made firmly. Therefore, high strength can be maintained.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an FRP pipe with a threaded joint manufactured by a manufacturing method of an embodiment.
FIG. 2 is an explanatory diagram showing a threaded connection state of an FRP pipe with a threaded joint manufactured by the manufacturing method of the embodiment.
FIG. 3 is an explanatory view showing a manufacturing process of the embodiment.
FIG. 4 is an explanatory diagram showing a manufacturing process of the embodiment.
FIG. 5 is an explanatory sectional view of a joint in a case where the joint of the present invention is a fitting joint and a flange joint.
FIG. 6 is an explanatory view showing a connection structure of a conventional FRP tube.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 FRP pipe with threaded joint 1a Unsaturated polyester resin 1b Glass fiber sheet 2 Male threaded joint pipe 2a Male threaded part 2b Thin part 3 Female threaded joint pipe 3a Female threaded part 3b Thin part 4 Core tube 5, 6 Sheet fixture 7 Rotational drive 8 Extraction Nozzle 10 FRP pipe 11 Joint pipe 11a, 11b Threaded portion 12 Taper 22, 23 Fitting joint 22a, 23a Thin portion 22b, 23b Fitting surface 24, 25 Flange joint 24a, 25a Flange 24b, 25b Bolt hole 24c, 25c Thin portion 26 volts

Claims (6)

At each end of the FRP tube forming position of the FRP tube forming core tube, a joint tube and a thin tube having irregularities on the outer peripheral surface provided on opposite sides of a joint tube are fitted in opposite directions so that the thin portions face each other. A release agent or a release tape is put on the surface of the core tube between the two pipe joints, and a reinforcing fiber sheet or a reinforcing fiber tape is coated on the opposed thin wall portion and the upper surface of the core tube therebetween, and a thermosetting resin is applied thereto. A method of manufacturing an FRP tube with a joint, in which the impregnated resin is cured to form the FRP tube with a joint by forming the FRP tube and integrating the joint tube. Male screw joint pipe with male screw part and thin part with irregularities on the outer peripheral surface provided at opposite ends of the FRP tube molding position of the core tube for FRP pipe molding, and irregularities on the female screw part and outer peripheral surface The thin-walled part and the female threaded joint pipe provided on the opposite sides are fitted with the thin-walled part facing each other, and a release agent or a peeling tape is applied to the surface of the core pipe between the male threaded joint pipe and the female threaded joint pipe. Cover the upper surface of the opposed thin wall and the core tube with a reinforcing fiber sheet or a reinforcing fiber tape, impregnate it with a thermosetting resin, and cure the impregnated resin to form an FRP tube and a male and female screw. A method of manufacturing an FRP pipe with a joint, in which the joint pipe is integrated to produce an FRP pipe with a threaded joint. At the end position of the FRP tube forming position of the FRP tube forming core tube, a threaded portion and a threaded joint tube provided with a thin-walled portion provided with irregularities on the outer peripheral surface on opposite sides are fitted and separated from the core tube surface. Covering the core tube surface and the upper surface of the thin-walled portion of the threaded joint tube with a reinforcing fiber sheet or a reinforcing fiber tape and impregnating the same with a thermosetting resin. A method of manufacturing an FRP pipe with a joint, wherein the molding of the FRP pipe with a male and female screw joint pipe is integrated to produce an FRP pipe with a screw joint. The method for manufacturing an FRP pipe with a joint according to claim 1, wherein the joint is a detachable fitting joint. The method for manufacturing an FRP pipe with a joint according to claim 1, wherein the joint is a flange joint connected by bolts. The method for producing a jointed FRP tube according to any one of claims 1 to 5, wherein the material of the reinforcing fiber sheet is glass fiber.

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