JPS6334124A - Manufacture of fiber reinforced plastic cylinder - Google Patents

Abstract

PURPOSE:To provide the title cylinder, having no leakage even in the case of molding the thin wall product, being easy in molding and consequently having enhanced production efficiency, by a method wherein a thin synthetic resin film is put on and, after that, a continuous resin-impregnated film is wound round a mold, in which a projected part forming section on the surface of a cylinder is divided peripherally so as to allow to move splits radially, in order to form a fiber-wound layer by curing. CONSTITUTION:The outer surface of a mold 1 is covered with a thin film layer 12, which is formed by winding a synthetic resin film round or by putting a synthetic resin tube, either non-shrinkable or heat-shrinkable, on the mold 1. A continuous resin- impregnated fiber is wound round the mold 1 onto the thin film layer 12 so as to form a thin fiber-wound layer 13 in order to obtain a fiber reinforced plastic (FRP) cylinder by curing matrix resin and, after that, removing from the mold. In order to remedy the poor dimensional accuracy of the outer surface of the FRP cylinder, an outer mold 20, the inner diameter of a cylindrical mold 22 in which is enlarged by evacuating an air space part 23, is fitted onto the mold 1, onto which the fiber- wound layer 13 is formed, so as to urge the cylindrical mold 22 to the fiber-wound layer 13 by releasing the evacuation of the air space part 23 and further, by contrary, pressurizing the air space part 23 in order to thermoform the layer 13.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a method for manufacturing a fiber-reinforced plastic (hereinafter referred to as FRP) hollow cylindrical body, and more specifically, a method for manufacturing a hollow cylindrical body made of fiber-reinforced plastic (hereinafter referred to as FRP), and more specifically, a method for manufacturing a hollow cylindrical body made of fiber-reinforced plastic (hereinafter referred to as FRP). Efficiently convert existing cylindrical bodies (,
The present invention also relates to a reliable manufacturing method.

[Conventional technology]

An FRP cylindrical body with uneven surfaces is wrapped with resin-impregnated continuous fibers using the filament winding method (hereinafter abbreviated as FW method) on a split mold that can be disassembled into multiple parts in the circumferential direction. Depending on the requirements, fiber wrapping is produced by covering the layer with an outer mold for shaping the outer surface, and then hardening and molding the whole.

Note that the reason why a split mold is used is to enable demolding after curing and molding.

[Problem that the invention seeks to solve]

When a thin-walled cylindrical body, such as a thin-walled FRP heros, is manufactured using the above-mentioned conventional method, gas or liquid leaks in areas where the resin is insufficiently impregnated between the fibers because the cylindrical body itself is thin. Sometimes. Moreover, the thinner the product, the more likely it is that leakage will occur, making it unsuitable for applications such as fluid transfer pipes.

In addition, from the viewpoint of ease of removing the product from the mold, the inner mold is usually a split mold as mentioned above, but in the split mold, the fiber wrapping is impregnated between the joint surfaces of the mold during molding. There is also the problem that the resin cannot be avoided from dripping into the mold, and as a result, a great deal of time is spent cleaning the inner mold after demolding, resulting in a very low production efficiency.

Therefore, the present invention aims to solve the problem of FR with concavities and convexities on the surface.
It is an object of the present invention to provide a manufacturing method that does not cause leakage even when a P cylinder is formed into a thin wall, is easy to form, and increases production efficiency.

[Means for solving problems]

The method of the present invention for solving the above problems is divided into two methods: a first method and a second method that eliminates the need for finishing of the product after demolding.

That is, a thin synthetic resin film is placed on a mold in which at least the convex molded portion on the surface of the cylindrical body is divided in the circumferential direction, and each of the divided bodies is moved and set in the radial direction by a drive mechanism, and then the resin is In the first method of the present invention, continuous fibers impregnated with the same material are wound, and the fiber-wrapping layer is then hardened and molded.

In addition, in the second method, the resin-impregnated continuous fibers are wrapped after the step in the first method, and the fibers are wrapped on the layer using a cylindrical shape made of a viscoelastic material and an outer cylinder that surrounds and holds it from the outside. The cylindrical mold and the outer cylinder are covered with an outer mold having a void between them, with the void in a reduced pressure state, and then the reduced pressure in the void is released and the cylindrical mold is covered with a fiber-wrapped layer. Under this condition, the fiber wrapping layer is hardened and molded.

[Effect]

According to the above method, the synthetic resin thin film covering the mold prevents the resin from flowing between the joint surfaces of the split mold. Therefore, cleaning of the inner mold becomes unnecessary, and efficient manufacturing with good workability becomes possible.

In addition, it is possible to integrate the above thin film with FRP@ to obtain a product in which both are laminated. In this case, even if it is a thin-walled molded product, the thin film can prevent fluid from leaking, so leaks can be prevented. The fear of is gone.

The above-mentioned effects are common to the first and second inventions, but in the second invention, the finishing accuracy of the outer surface of the product is improved by the molding action of the cylindrical outer mold, and therefore the product after demolding is This has the unique advantage of eliminating the need for machining the outer surface of the material.

〔Example〕

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

The illustrated method takes as an example the production of a cylindrical body with a bellows shown in FIG. 5, that is, a cylindrical body A in which a bellows part exists in the middle of a cylindrical part a.

First, the mold 1 used as the inner mold is shown in Figures 2 and 3.
It has the structure shown in the figure. That is, the convex mold 3 on the surface of the cylindrical body separated from the cylindrical mold 2 is divided in the circumferential direction, and each of the divided bodies 3a, 3a', 3b, and 3b' is provided with a symmetrical tapered surface 4a. A guide plate 4 with an attached guide plate 4 and a guide rod 5 that is slidably supported in the radial direction by a core bar 6 that supports the cylindrical mold 2 concentrically are attached. Furthermore, tapered rings 7 each having a tapered surface 7a corresponding to the tapered surface 4a are arranged on both sides of the guide plate 40, and each tapered ring 7 has a cylindrical mold 2 extending in opposite directions. A slide rod 8 passing through the end wall of the metal core in the axial direction of the metal core is connected thereto.

Then, the bearing 1 is attached to a pusher 10 in which a ring S fixed to the other end of each slide rod is screwed to the threaded portions at both ends of the core metal.
It is installed via 1. The above-mentioned mechanical elements except the mold 2.3 and the core metal 6 constitute a drive mechanism for the convex mold 3, and the left and right slide rods 8 move toward and away from each other as the pusher 10 rotates. The direction of this linear motion is changed by the tapered engagement of the tapered ring 7 and the temporary guide 4, and each of the divided bodies 3a, 3a', 3b, and 3b' is guided into the guide hole 6a of the core metal by the guide rod 5. It is adapted to move in the radial direction along with the radial direction. The radial positioning of each segment of the convex mold 3 is performed with the outer surface of the cylindrical mold 2 as a reference.

As shown in FIG. 1, the mold 1 configured as described above is wrapped with a synthetic resin film or covered with either a non-shrinkable or heat-shrinkable synthetic resin tube, preferably tightly. The outer surface of the mold 1 is covered with a thin film layer 12 made of these materials. Next, resin-impregnated continuous fibers are wound on the mold 1 from above the thin film layer 12 by the FW method. 13 is formed.Then, the matrix resin is cured by heating, etc., and removed from the mold to complete the first method and obtain the desired FRP cylinder.The FRP cylinder is
When resin-impregnated fibers are directly wrapped around 1fflli12, F
It is a laminated product in which the RP layer and the thin film layer are bonded together, but before wrapping the fibers, it is necessary to apply a release agent to the surface of layer 12,
The layer 12 may be peeled off from the FRP product at the time of demolding by using a material such as a fluororesin having good mold releasability for the WJ12 itself, and in this case, the M12 can be used repeatedly.

Next, since the FRP cylindrical body obtained by the above method has poor dimensional accuracy on the outer surface, depending on the use, it is necessary to finish the outer surface by mechanical processing.

Therefore, in the second method, this processing step is omitted (in order to
An outer mold 20 as shown in FIG. 4 is employed.

This outer mold includes an outer cylinder 21 and a cylindrical mold 22 made of a viscoelastic material such as rubber placed inside the outer cylinder 21, with a gap 2 between them.
3 exist and are combined.

Cylindrical type 2 with unevenness on the inner surface that corresponds to the surface unevenness of the cylinder
Both ends of the rib 2 are held between an annular rib 24 provided on the inner surface of the outer cylinder and a tightening ring 25, and this holding part is the rib 2.
A cavity 2 whose radial spatial dimension is determined by the height of 4.
It also serves as an airtight seal on both ends of 3. 26 is a hole for pressurization or depressurization provided in the outer cylinder.

In this outer mold 20, when the pressure inside the cavity 23 is reduced, the inner diameter of the cylindrical mold 22 expands due to the pressure difference with the atmosphere. In the enlarged state, the outer mold 20 is fitted onto the mold 1 on which the fiber-wrapped layer 13 has been formed, and then the vacuum inside the cavity 23 is released and pressure is applied conversely, and the cylindrical mold 22 is wrapped with fibers. The attachment is brought into pressure contact with the layer 13 and the whole is heated and molded.

After the matrix resin has hardened, the cavity 23 is depressurized again, the mold 1 is extracted, and the mold 1 is removed from the product. The FRP cylindrical body shown in the figure is obtained.

〔effect〕

As described above, according to the present invention, the inlet between the joint surfaces (divided surfaces) of the split molds is closed with a synthetic resin thin film and then the resin-impregnated continuous fibers are wrapped around the molds. Since it eliminates the inflow of resin between surfaces and eliminates the need for cleaning the mold, the work is simplified and FR
The production efficiency of P cylindrical bodies is increased.

Further, since it is possible to obtain a hardening that prevents fluid from leaking due to the thin film by integrating the synthetic resin thin film with the FRP layer, there is no need to worry about fluid leakage even if the product is a thin film molded product.

Furthermore, in the second method, the finishing accuracy of the outer surface of the product is improved due to the shaping effect of the outer mold, which eliminates the need for machining the outer surface after demolding, increasing productivity. The effect of further improvement can also be obtained.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the first method of the present invention, Fig. 2 is a sectional view showing an example of a mold used in the method, with half of the central axis omitted, and Fig. 3 is the same as Fig. 2. FIG. 4 is a cross-sectional view showing an example of an outer mold used in the second method of the present invention, and FIG. 5 is a cross-sectional view of an FRP cylinder manufactured using the example mold. It is a side view of a body. 1... Molding mold, 2... Cylindrical mold, 3
...Convex mold, 3a, 3a', 3b, 3b
' ・・・・・・・・・Divided body, 4・・・・・・Guide quick turn,
5... Guide rond, 6... Core metal, 7
...Taper ring, 8...Slide rod, 10...Push stand, 12...Synthetic resin thin film layer, 13...Fiber The wrapping is layered, 20.
...Outer mold, 21...Outer cylinder, 22...
...Cylindrical shape, 23...Void part, A...
FRP cylindrical body. Patent applicant Sumitomo Electric Industries, Ltd. Agent Kama 1) Text 2 Figure 1 Figure 3 Figure 4 Figure 5

Claims (3)

[Claims] (1) A thin synthetic resin film is placed on a mold in which at least the convex molded portion on the surface of the cylindrical body is divided in the circumferential direction and each of the divided bodies is moved in the radial direction by a drive mechanism, and then 1. A method for producing a cylindrical body made of fiber reinforced plastics, which comprises winding continuous fibers impregnated with the same material, and then hardening and molding the fiber-wrapped layer. (2) The method for manufacturing a cylindrical body made of fiber-reinforced plastics according to claim (1), wherein the thin film made of synthetic resin is in the form of a tube. (3) A thin synthetic resin film is placed on a mold in which at least the convex molded portion on the surface of the cylindrical body is divided in the circumferential direction and each of the divided bodies is moved in the radial direction by a drive mechanism, and then Next, a cylindrical shape made of a viscoelastic material and an outer cylinder that surrounds and holds the cylindrical shape from the outside are provided on the fiber-wrapped layer, and a gap is formed between the cylindrical shape and the outer cylinder. The outer mold provided with this is covered with the cavity under reduced pressure, and then the vacuum in the cavity is released to bring the cylindrical mold into close contact with the fiber-wrapped layer, and under this condition, the fiber-wrapped layer is hardened and molded. A method for producing a cylindrical body made of fiber-reinforced plastics, characterized by: