JPS61279535A - Manufacture of bent pipe and tapered pipe - Google Patents

Abstract

PURPOSE:To improve the strength and rigidity of a bent pipe or tapered pipe by a method wherein a prepreg made of high strength fiber yarns, which are braided obliquely and axially with respect to the direction of the axis center line of the bent pipe or tapered pipe and impregnated with thermosetting resin, is employed. CONSTITUTION:When a prepreg is formed by impregnating a sleeve consisting of high strength fiber yarns braided obliquely with respect to the direction of the axis of a pipe (angle plies) and high strength fiber yarns braided axially with respect to the direction of the pipe axis (straight plies) with thermosetting resin, the angle ply 2 is braided obliquely at an angle of 5-85 deg. with respect to the axis direction. Carbon fiber, silicon carbide fiber, polyamide fiber or the like is used as the material employed in the angle ply 2 and the straight ply 3. Epoxy resin, phenolic resin, urea resin or the like is used as the thermosetting resin 1. The prepreg is laminated onto a core material and subjected to rolling and, after that, the core material is pulled out in order to obtain an annular base material. A rubber sack 4 is inserted in the inside of said annular base material, the outside of which is covered with mold material and pressed so as to form a bent part in order to be cured by heating. Thus, a FRP pipe, not only the strength and rigidity on the circumferential direction but also those in the axial direction of which are excellent, can be manufactured.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to bent pipes and tapered pipes, and more specifically to prepregs in which high-strength mH threads are braided in a specific arrangement and further impregnated with a thermosetting resin. This invention relates to bent pipes and tapered pipes with improved strength and rigidity using as a base material.

[Prior Art] Conventionally, as a method for reinforcing bent tubes and tapered tubes (hereinafter collectively referred to as F and RP tubes) made of thermosetting resin such as tone arms and zero-shaped heaters, fiber threads or metal wires were spirally reinforced. The base material was made by braiding or filament winding and impregnating it with a thermosetting resin.

FRPIF, whose base material is a prepreg sheet (hereinafter referred to as a "normal sheet") in which 8M threads are braided only diagonally to the axial direction and impregnated with a thermosetting resin, is Because there is no component, the strength and rigidity in the tube axis direction are low.

In addition, when using the base material as a straight pipe, the base material is a prepreg sheet (hereinafter referred to as UD sheet) in which fiber threads are braided only in the axial direction and a fabric is laminated with a prepreg sheet (hereinafter referred to as UD sheet) impregnated with a thermosetting resin. Although it has sufficient strength and rigidity, the following problems occur when it has a bent part such as a bent pipe.

That is, since the woven fabric itself has a low degree of expansion and contraction and does not easily cause UD receipt thread displacement, the fiber threads meander inside the bending portion and create gaps locally, reducing strength and rigidity. Although UD receipts are generally used in a laminated manner, they have the disadvantage that delamination occurs between the sheets at bent portions, resulting in a decrease in strength.

In addition, in order to reinforce the synthetic resin or rubber, a method for manufacturing pipes using a base material made of synthetic fiber threads, metal wires, etc. braided diagonally and axially with respect to the pipe axis direction was published in Japanese Patent Publication No. 56-45387.
It is disclosed in the publication No. However, this method cannot prevent delamination as well as the method using the above-mentioned LID sheet, and the
It is not possible to manufacture P pipes.

As described above, the current situation is that it has not been possible to obtain FRP pipes with satisfactory strength and rigidity.

[Problem to be solved by the invention 1 The present invention has been made to solve the above-mentioned problems,
The purpose of the present invention is to provide an FRP pipe with improved strength and rigidity, which is made of a base material made of braided high-strength IIH yarn impregnated with a thermosetting resin.

[Means and actions for solving the problem] This object of the present inventor is achieved by an FRP pipe having the configuration shown below.

That is, the present invention is characterized in that a prepreg in which high-strength fiber threads are braided diagonally and axially with respect to the axial direction of the curved or tapered pipe obtained and impregnated with a thermosetting resin is used as the base material. For curved and tapered pipes.

Hereinafter, the present invention will be explained based on the drawings.

FIGS. 1(a) to 1(e) are diagrams illustrating a series of steps of a method for manufacturing a bent pipe according to the present invention.

In the present invention, when a bent tube is made, high-strength fiber yarns braided diagonally with respect to the tube axis direction (hereinafter referred to as angle braid) and high-strength mm yarn braided in the tube axis direction (hereinafter referred to as straight braid) are used. A prepreg having a structure as shown in FIGS. 5A to 5C is manufactured by impregnating a thermoplastic resin into a sleeve. In the figure, numeral 1 indicates a thermosetting resin that serves as the base material of the bent pipe. 2 indicates an angle braai, and 3 indicates a straight braai.

In this case, the angle bridle 2 is 5° to 8° with respect to the axial direction of the resulting pipe, depending on the required strength and rigidity of the bent pipe.
Braided at any angle of 5°. The smaller the angle, the higher the strength in the axial direction, but the lower the strength in the circumferential direction.

Further, the thickness, number, etc. of the angle braai 2 and the straight braai 3 are appropriately selected depending on the strength and rigidity required for the bent pipe.

Examples of the material for the high-strength fiber thread used in the angle braai 2 and the straight braai 3 include carbon fiber, silicon carbide fiber, polyamide fiber, silicon nitride fiber, and alumina fiber. High strength made of these materials! 1
If necessary, two or more kinds of IIl threads can be used in combination. In the present invention, since it has high strength fiber yarns not only in the diagonal direction but also in the axial direction, excellent strength and rigidity can be obtained in both the axial direction and the circumferential direction.

Examples of the thermosetting resin 1 used in the present invention include epoxy resin, phenol resin, urea resin, and melamine resin.

This prepreg is laminated onto a core material (not shown) and rolled, and by removing the core material, it becomes a hollow annular base material with a uniform thickness.

Furthermore, as shown in FIG. 4(d), a rubber bag 4 is inserted inside the hollow annular base material, and the outside is covered with a mold material (not shown). The rubber bag 4 and the mold material are used to prevent the cross-sectional shape and thickness of the hollow annular base material from being deformed at the bent portion. In this state, a bent portion is formed in the hollow annular base material by applying external pressure to the rubber bag 4 and the mold material from the outside.

Next, the material is heated and cured under pressure to obtain a bent pipe as shown in FIG. 2(e).

An example of an FRP pipe manufactured by the method of the present invention is shown in FIG. The same figure (a) shows the tone arm 5, the same figure (b) shows the wheelchair frame 6, the same figure (C) shows the coil spring 7, and the same figure (d> shows the 0-shaped heater 8. These are manufactured according to the present invention. The present invention is not limited to these specific examples of FRP pipes that can be used, but is applicable to all FRP pipes.

[Examples] The present invention will be specifically described below based on Examples and Comparative Examples.

1 and Comparative Examples 1 to 2 Using prepreg reinforced with angle and straight brazes and impregnated with thermosetting resin as shown in Figures 1(a) to (C), as shown in Figure 2(b) A wheelchair frame like this was manufactured (Example 1).

For comparison, wheelchair frames were manufactured in the same manner using prepreg reinforced only with angle braises (normal seat) and prepreg reinforced only with straight braises (UD receipt) (Comparative Examples 1 and 2).

As shown in Fig. 3, this wheelchair frame has one end as a fixed end and the other end as a free end, and a load is applied to the bent part, and the displacement of the free end in the load direction (y) with respect to the breaking load (kc+) and a load of 5 ka. (m) and the direction perpendicular to the load direction (X
) was measured. The results are shown in Table 1.

Table 1 As shown in Table 1, Example 1 has a larger breaking load than Comparative Examples 1 and 2. Further, in Example 1, the displacement in both the X direction and the y direction is small, but in Comparative Example 1 using an angle braai, the displacement in the X direction is large, and in Comparative Example 2 using a straight braai, the displacement in the y direction is large. .

[Effects of the Invention] As explained above, according to the present invention, the following effects are achieved.

■ Because the straight braai runs in the axial direction of the tube,
It is possible to manufacture an FRP pipe that has excellent strength and rigidity not only in the circumferential direction but also in the axial direction.

■ By adjusting the number and thickness of straight braises and the braiding angle of angle braais, it is possible to manufacture FRP pipes with desired strength and rigidity.

■ The manufacturing process is simple because the base material can be easily braided in one step.

- By making the angle braai into ultra-fine threads that do not contribute to the strength of the bent pipe, it is possible to manufacture FRP pipes that have essentially only straight braises.

In addition, in order to further improve the density, it is also possible to bake the FRP pipe of the present invention, impregnate it with resin or pitch, and repeat the baking and impregnation to obtain a carbon-carbon composite material.

[Brief explanation of the drawing]

FIGS. 1(a') to (e) are diagrams explaining a series of steps of the manufacturing method of the present invention, and FIGS. 2(a) to (e) are FRs manufactured by the present invention.
It is a figure showing a specific example of a P pipe. FIG. 3 is a schematic diagram of a wheelchair frame showing the test method of Example 1 and Comparative Examples 1 and 2. 1...Thermosetting resin, 2...Angle braai, 3.
...Straight bra, 4...Rubber bag, 5...Tone arm, 6...Wheelchair frame, 7...Coil spring, 8...Character 0 heater. Patent Applicant Japan Carbon Co., Ltd. Agent Patent Attorney Tatsuo Ito Attorney Patent Attorney Tetsuya Ito Figure 2 Figure 3 Proceeding Officer 11j Self-motivation) July 3, 1985 1 Director-General of the Office Ubuya Michi Department Indication of the Tono case 1985 Patent application No. 121521, name of the invention Method for manufacturing bent pipes and tapered pipes 3, relationship with the person making the amendment case Patent applicant residence Location 2-6-1 Hatchobori, Chuo-ku, Tokyo Title: Nippon Carbon Co., Ltd. Representative Sakiri Ishikawa

Claims (1)

[Claims] 1. A prepreg in which high-strength fiber threads are braided diagonally and axially with respect to the axial direction of the resulting bent or tapered pipe, and the prepreg is impregnated with a thermosetting resin is used as the base material. Bent pipes and tapered pipes characterized by: 2. The bent pipe and tapered pipe according to claim 1, wherein the high-strength fiber is selected from carbon fiber, silicon carbide fiber, polyamide fiber, silicon nitride fiber, and alumina fiber. 3. The bent pipe and tapered pipe according to claim 1 or 2, wherein the thermosetting resin is selected from epoxy resin, urea resin, phenol resin, and melamine resin.