JPS61220833A - Manufacture of curved pipe made of fiber reinforced plastics - Google Patents

Abstract

PURPOSE:To facilitate to curve the pipe and release it from a mold since slip is readily caused between thin sheets mutually and other sheets can be pulled out easily when one sheet thereof is pulled out, by a method wherein a mold is formed by superposing a plurality of thin sheets of metal or the like. CONSTITUTION:The mold 1 is consisting of a plurality of thin sheets 2 of metal or the like, which are superposed into the same direction. FRP forming filament, consisting of continuous fibers of glass fibers, carbon fibers or the like which are impregnated with a resin, are wound around the outer peripheral surface of the mold 1 to form a filament layer 5. Then, jigs 6 are fitted to both ends of the thin sheets 2 so that the thin sheets 2, protruding respectively from both ends of the filament layer 5, are not loosened mutually and, thereafter, both ends of the thin sheets are fixed. The pipe is curved so as to have a predetermined curvature under pushing the central parts of the sheets properly by the jigs and the resin in the filament layer 5 is heated and cured under keeping the curved condition of the pipe. Subsequently, the thin sheets 2 in the filament layer 5 is pulled out sequentially and whereby the curved pipe, made of FRP, may be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a fiber reinforced plastics (hereinafter referred to as FRP) pipe bent at a predetermined curvature.

[Conventional technology and its problems]

When manufacturing a bent FRP pipe with a predetermined curvature by the filament winding method, in which a filament made of continuous fibers impregnated with resin is wound around a mold and then heated and hardened, the filament is Problems include uneven winding, impossibility of filament winding due to the large curvature of the pipe, various measures required during the curing process, and increased weight due to combination with metal or other materials. There is, FRp
H! The production of bent pipes was technically extremely difficult.

By the way, as a conventional method, for example, there is a method using shape memory metal as a core material (Japanese Patent Application Laid-open No. 57-22016), but these methods require a heavy molded product due to the combination with metal, and also There is a problem of peeling between metal and FRP.

Another method is to heat the pipe to a temperature higher than the heat distortion temperature after forming the pipe, and bend it by applying an external force (Japanese Patent Laid-Open No. 59-2
No. 1769), but this method has a problem in that the bending range is limited and defects such as microcracks are likely to occur. Also, FRPJ for tennis and badminton.
The method of using fibers made of FiLP material in a braided manner, as in the case of manufacturing the racket I, is easy to mold, but it has the problem of not being able to increase the fiber content and the problem of the diameter. There was a problem that large pipes could not be manufactured.

Therefore, the present invention aims to provide a method for manufacturing a bent pipe made of FRP without the above-mentioned problems.

[Means for solving problems]

This invention involves forming a filament layer by winding a filament made of continuous fibers impregnated with resin on the surface of a filament winding mold formed by stacking a plurality of thin metal plates in the same direction. After bending the filament layer together with the mold by applying bending stress in the thickness direction of the thin plate, and heating and hardening the structural resin of the filament layer while maintaining its curvature, the thin plate forming the mold is It is designed to extract the.

[Effect]

In this method, a bent pipe is formed by bending a filament layer together with a filament winding mold in which filament 1 is formed on the outer peripheral surface. Since it is made of stacked plates, when bending it, it is easy to cause misalignment between the two thin plates, making it very easy to bend.
Moreover, when demolding, if one thin plate is pulled out, the other thin plates can be easily pulled out, so demolding is extremely easy.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

first,! $1 Manufacture a mold 1 for filament winding as shown in the figure.

This mold 1 for filament winding is made by stacking a plurality of thin plates 2 made of metal or the like in the same direction, and a jig 3 for fixing the thin plates 2 is fitted on both sides. 3 is provided with a shaft 4 for mounting a mold on the winding machine. The cross-sectional shape of this mold 1 for filament winding is made to correspond to the external shape of the pipe to be molded, and FIGS. 1 and 2 show a valley mold for molding a square pipe, and FIG. 3 shows a valley mold for molding a circular pipe. Shows the mold.

Hereinafter, a method for manufacturing an FRP bent pipe A having a square cross section as shown in FIG. 6 using the filament winding mold 1 shown in FIGS. 1 and 2 will be described.

After setting the filament winding mold 1 in a winding machine, a filament for FRP molding made of continuous fibers such as glass fiber or carbon fiber impregnated with resin is wound around the outer peripheral surface of the mold 1. Form 5.

Next, after removing the filament winding mold 1 from the winding machine, the jigs 3 at both ends are removed.

After that, in order to prevent the thin plates 2 protruding from both ends of the filament layer 5 from coming apart, a jig 6 is fitted to both ends of the thin plate 2, and both ends are fixed, and the central part is fixed with an appropriate jig. While pressing the filament 115, bend it to a desired curvature, and heat the resin of the filament 115 while maintaining that state (see FIG. 5).

Next, by sequentially pulling out the thin plates 2 in the filament layer 5, a bent pipe A made of FRP as shown in FIG. 6 is manufactured.

In this method, if you want to manufacture a pipe with a better inner surface condition, you can attach a rubber tube or a heat shrink tube to the thin plate 2 part of the filament winding mold 1 during winding. The surface condition of the mold may be improved by covering the thin plates 2 to eliminate the gap between them.

〔effect〕

Since the present invention is as described above, it has the following effects.

■ Since the filament is basically wound using the filament winding method, it is possible to manufacture products with a high fiber content.

■ Since multiple thin plates are stacked on top of each other without being glued together, when bending stress is applied, each thin plate shifts and easily bends, which requires an expensive bag for bending. I don't.

■ When demolding, multiple thin plates are used even for curved pipes, so if one thin plate is pulled out, a gap is created inside the pipe, and other thin plates can be easily pulled out. .

Therefore, demolding is extremely easy.

(2) By changing the shape of the thin plate, a mold with an arbitrary cross-sectional shape can be formed, so it is possible to mold a bent pipe with an arbitrary cross-sectional shape.

[Brief explanation of the drawing]

Figure 1j81 is a perspective view showing an example of a mold for filament winding, Figure 2 is a sectional view of the same as above, Figure 3 is a sectional view showing the other side of the mold for filament winding, $4
The figure is a cross-sectional view of the mold shown in Figure 1 with a filament layer formed on the outer circumferential surface, Figure 5 is a perspective view showing the mold in which filament II is formed in a bent state, and Figure 6 is an FRP manufactured by the present invention. It is a perspective view showing an example of a bent pipe. 1...Mold for filament winding, 2...
Thin plate, 5... filament - Patent applicant Sumitomo Electric Industries, Ltd. Agent
Sickle 1) Sentence 2 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (5)

[Claims] (1) After forming a filament layer by winding a filament made of continuous fibers impregnated with resin on the surface of a filament winding mold formed by stacking multiple thin plates of metal etc. in the same direction, The filament layer is bent together with the mold by applying bending stress in the thickness direction of the thin plate, and the resin of the filament layer is heated and hardened while maintaining its curvature, and then the thin plate forming the mold is pulled out. A method for manufacturing bent pipes made of fiber-reinforced plastics. (2) The method for manufacturing a bent pipe made of fiber-reinforced plastics according to claim 1, wherein the filament winding mold has a rectangular cross-sectional shape. (3) The method for manufacturing a bent pipe made of fiber-reinforced plastics according to claim 1, wherein the filament winding mold has a circular cross-sectional shape. (4) Manufacture of a bent pipe made of fiber-reinforced plastics according to any one of claims 1 to 3, wherein the surface of the filament winding mold is covered with an elastic tube made of rubber or the like. Method. (5) The method for manufacturing a bent pipe made of fiber-reinforced plastics according to any one of claims 1 to 3, wherein the surface of the filament winding mold is covered with a heat-shrinkable tube.