JPH0415731B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a filament winding forming method that is advantageous for manufacturing pipes.

[Prior art]

Conventionally, when a cylindrical or rectangular pipe is molded by filament winding, the winding angle of the resin-impregnated fiber approaches 90 degrees with respect to the pipe axis at both ends of the pipe, resulting in a disadvantage that the pipe ends bulge (dogbone effect). In order to prevent the defects caused by this dockbone effect from being reflected in the pipe, the raised part at the end of the pipe is cut off, which results in wasted material and reduces the strength of the end because the fibers are broken at the end. There was a problem with the decrease in Also, if you try to manufacture a pipe without cutting the ends, the winding angle at the ends must be smaller than 90° (in the case of helical winding), which can cause fiber thread misalignment. Resulting in.

[Purpose of the invention]

The present invention was made in order to solve the various problems of the conventional art, and it is possible to obtain a pipe with uniform mechanical strength at any part without cutting the ends. It is an object of the present invention to provide a filament winding molding method that does not cause the dogbone effect.

[Structure of the invention]

Therefore, in the present invention, a ring made of fiber-reinforced plastic with a plurality of pins implanted on the outer peripheral surface is fitted onto both ends of a mandrel, and resin-impregnated fibers of the same quality as the ring are folded back by the pins of the ring. The gist is a filament winding forming method characterized by winding the filament around a mandrel at a predetermined winding angle. here,
The winding angle refers to the inclination angle of the resin-impregnated fiber with respect to the axis of the mandrel when the resin-impregnated fiber is wound around the mandrel.

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

In FIG. 1, 1 is a mandrel used when performing filament winding molding. Rings 2 having a plurality of pins 3 implanted on the outer peripheral surface are fitted into both ends of the mandrel 1 as shown by the arrows.

This ring 2 is made of fiber-reinforced plastic, and as shown in FIG. 2, it is obtained by bending a rectangular flat plate 4 with pins 3 implanted on its surface in the direction of the arrow and bringing both ends into contact with each other. It will be done. The size of the ring 2 may be determined as appropriate depending on the size of the mandrel 1. In addition, mandrel 1 is
The shape may be either cylindrical or rectangular. The rectangular flat plate 4 with the pins 3 implanted on its surface as shown in FIG. A steel plate having a thickness equal to the height of the pin 3 with a plurality of holes suitably drilled therein is placed, and the holes are filled with liquid resin-impregnated glass fiber of the same quality as the prepreg sheet, and after hardening, the steel plate is It can be obtained by removing.

When fitting the ring 2 to both ends of the mandrel 1, as shown in FIG. 3, a prepreg sheet of the same quality as the ring 2 is laminated on the surface of the mandrel 1 in advance to form the innermost layer 5 of the pipe.
It is preferable to fit the ring 2 through an adhesive layer 6 that is compatible with this innermost layer 5. Thereby, the ring 2 can be firmly adhered to the innermost layer 5.

After fitting the ring 2 to both ends of the mandrel 1 in this way, the resin-impregnated fibers are attached to the pins 3 of the ring 2.
Wrap it around the mandrel 1 at a predetermined winding angle using the usual method while folding it back at the same time. This winding angle is typically ±
It is about 45°. In this case, the same resin-impregnated fiber as that of the ring 2 is used. Examples of the fiber include glass fiber and carbon fiber. Further, as the resin, for example, epoxy resin, unsaturated polyester resin, etc. are liquid at room temperature and harden by heating.

By winding this resin-impregnated fiber around the mandrel 1, curing it by a conventional method, and then pulling it out from the mandrel 1, a pipe can be manufactured without cutting the reinforcing fibers.

〔Effect of the invention〕

As explained above, according to the present invention, the ring 2
are fitted onto both ends of the mandrel 1, and the resin-impregnated fibers of the same quality as the ring 2 are wound around the mandrel 1 at a predetermined winding angle while being folded back by the pins 3 of the ring 2, so that the following effects can be achieved.

(1) Since the ring 2 and pin 3 are integrated with the resulting pipe, the mechanical strength of the pipe end is improved.

(2) When the resin-impregnated fibers are wound around the mandrel 1, they are folded back by the pins 3, which reduces the deviation of the reinforcing fibers and the deviation of the winding angle, making it possible to obtain a pipe with uniform mechanical strength at any location.

(3) Since the pipe can be manufactured without cutting the reinforcing fibers and matrix resin, there is no wastage of materials and material costs can be saved.

Examples are shown below.

Example 1 Rectangular flat prepreg sheet (G120/F6986SO3−) made of glass cloth impregnated with liquid resin
S920NM, Yokohama Rubber) is placed on the surface of a steel plate with multiple holes appropriately drilled in it, and the holes are filled with Epicoat.
Glass roving (Tex575, Asahi Fiberglass) is made by mixing 828 (epoxy resin, oil-based shell epoxy) and methyl hymic acid anhydride (acid anhydride, Hitachi Chemical) in equal amounts.
filled with impregnated water, 120℃ x 90 minutes, 3.0Kg
After curing at f/cm ² G, the iron plate was removed to obtain a ring 2.

Next, Daifree (a fluorine-based mold release agent, manufactured by Daikin) is applied to the surface of the mandrel 1, and a prepreg sheet of the same quality as the ring 2 is laminated around the entire circumference of the mandrel 1 to form the innermost layer 5 of the pipe. Ta. Apply epoxy film adhesive (FM123-5,
American cyanamide) is applied to form an adhesive layer 6, and the ring 2 is attached via this adhesive layer 6.
were fitted into both ends of mandrel 1, respectively.

Next, the winding angle ±
I performed filament winding while turning back with pin 3 of ring 2 at 45 degrees. After curing the resulting winding product at 120℃ for 3 hours,
It was left for 7 hours + 160°C x 3 hours, and then pulled out from mandrel 1. A cylindrical pipe with uniform mechanical strength and no glass roving displacement was obtained.

Example 2 The same procedure as Example 1 was carried out except that carbon roving (T300B, 3K, Toray) was used and the winding angle was ±30°.

A rectangular cylindrical pipe with uniform mechanical strength and no carbon roving displacement was obtained.

Example 3 Aromatic polyamide fiber (Kevlar 49, 1420d,
The same procedure as in Example 1 was carried out except that DuPont) was used.

A cylindrical pipe with uniform mechanical strength and no fiber displacement was obtained.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing how to fit a ring on both ends of a mandrel, Fig. 2 is an explanatory diagram showing an example of a method for making a ring, and Fig. 3 is an example of a method for fitting a ring on both ends of a mandrel. FIG. 1...Mandrel, 2...Ring, 3...Pin, 4...
Rectangular flat plate, 5... Innermost layer of pipe, 6... Adhesive layer.

Claims (1)

[Claims] 1 A ring made of fiber-reinforced plastic with a plurality of pins implanted on the outer circumferential surface is fitted onto both ends of a mandrel, and a resin-impregnated fiber of the same quality as the ring is folded back by the pins of the ring while being wound around the mandrel at a predetermined angle. A filament winding molding method characterized by winding.