JPH0128697B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a bellows made of fiber-reinforced composite material, and more specifically, the present invention relates to a method for manufacturing a bellows made of fiber-reinforced composite material. The present invention relates to a method of manufacturing a bellows made of material.

Cylinders made of fiber-reinforced composite materials have high strength and excellent corrosion resistance, so they are widely used in applications such as gas or liquid transport pipes, as well as high-speed rotation cylinders due to their excellent specific strength and specific elasticity. It will be done. Bellows are used for such purposes, for example, to make gas or liquid transport pipes easier to bend, or to absorb the elastic bending vibrations of high-speed rotating cylinders that rotate at a constant speed that exceeds the dangerous speed, thereby reducing the dangerous speed. This can be said to be an effective joint shape.

However, unlike homogeneous materials, fiber-reinforced composite materials exhibit extreme anisotropy, so there are various problems in molding them into a bellows shape, and at present they have not been put to practical use. In other words, considering the role of the bellows part, it is essential that it be as strong in the circumferential direction as the other parts of the cylinder, and that it is easy to bend and strong against bending, but the strength of the fiber reinforced composite material depends largely on the arrangement, density, and continuity of the fibers, and even in the case of a bellows shape, the problem is how to arrange the continuous fibers without cutting them and without disturbing the fibers as designed.

In addition, considering the use of high-speed rotating bodies, fiber-reinforced composite materials with excellent specific strength and specific elasticity, such as carbon fiber reinforced plastics (abbreviated as CFRP), are often designed to withstand centrifugal force to the maximum extent possible, making it necessary to introduce bellows. There is no point in introducing it if it causes a decline in mechanical performance due to the above-mentioned causes such as cutting of fibers and disturbance of the winding angle.Furthermore, there is no point in introducing it if it causes a decrease in mechanical performance due to the above-mentioned causes such as cutting of fibers and disturbance of the winding angle. Since there is a risk of elastic bending vibration occurring when a long-bodied, high-speed rotating body passes through a critical speed, a method is used to suppress vibration as much as possible by adjusting the balance, but as the critical rotational speed increases, fine adjustment of the balance becomes necessary. Therefore, applying bellows to reduce the critical speed can be said to be an extremely effective means from an industrial standpoint.

From this point of view, in order to obtain a bellows made of fiber-reinforced composite material that is strong and easy to bend without reducing strength in the circumferential direction, continuous fibers are used, and machining that would lead to the cutting of continuous fibers is suppressed as much as possible in the design. It is essential to maintain the winding angle and eliminate disorder of the fibers, and the inventors of the present invention have completed the present invention as a result of intensive research into the manufacturing method. The present invention will be described in detail below with specific examples.
The manufacturing method of the present invention is not limited to specific examples.

Bellows made of fiber-reinforced composite material are shown in Figure 1 or Figure 2.
As shown in the figure, it is used as a joint for a cylindrical body, and as shown in FIG.
Either the cylindrical part 10 and the bellows part 20 are manufactured separately using continuous fibers and then joined together using an adhesive, as shown in Fig. 2. integrated by.

Currently, when manufacturing a bellows shape by winding it around a mold using the winding method, manufacturing is considered difficult due to the following points.

It is difficult to wrap fibers along a bellows shape, and in many cases the fibers slide sideways or run in a straight line connecting peaks, and the bellows shape that fibers run along has small irregularities or is difficult to wrap due to the winding angle. Since the shape is uniquely limited, it cannot be said to be practical.

If the fibers running on a straight line connecting the ridges are made to follow a bellows shape by external force, the fibers will slide sideways, making it impossible to maintain a predetermined wrapping angle, and the wall thickness will become thinner. Moreover, if it is pressed down forcibly, there is a risk of fiber breakage.

In order to make the thickness of the fiber-reinforced composite material uniform along the bellows shape, it is possible to machine the outer diameter side, but with a complex shape like a bellows, machining itself is difficult, and the wrapped fibers are difficult to machine. This is not appropriate as there is a risk of cutting.

One possibility is to use an outer mold to eliminate uneven thickness, but in this case the outer mold needs to be a split mold, which tends to cause fibers to get caught in the mating surfaces of the molds, and this gets caught in the axial direction. This results in the cutting of continuous fibers, making it impossible to obtain a material with satisfactory strength, making it impractical.

Therefore, the inventors of the present invention first conducted extensive research to devise a wrapping mold that can maintain a predetermined wrapping angle and easily conform to the bellows shape.
A specific example is shown in the figure. A split mold 3 having a bellows shape divided in the circumferential direction is divided in the axial direction, and a winding mold is formed by inserting a spacer ring 4 having an outer diameter larger than the trough of the bellows. Invented it.

In the specific example shown in FIG. 3, a bellows-shaped split mold 3 is fixed by a cylindrical mold 2 and a core mold 1 passing through the cylinder, and a spacer ring 4 is also divided in the circumferential direction and each is fixed to the core mold 1 by a shaft 5. ing.

When winding using the winding type shown in Figure 3, first make the outer diameter of the spacer ring larger than the trough of the bellows, and in this state wrap the continuous fiber impregnated with the matrix. After finishing, use the nut 6 prepared inside the core mold 1 to drop the spacer ring 4 below the valley of the bellows through the shaft 5, and then move the split mold 3 in the axial direction using the cylindrical mold 2 to remove the bellows. Make it into a mold with a shape. The ring dropped here is stored in the space provided in the split mold 3 in advance.

In other words, when using this wrapping mold, the width of the spacer was adjusted to be enough to cover the surface of the bellows shape with the fibers running on the straight line connecting the peaks of the bellows, which was a problem. This eliminates the need to forcibly force the fibers into the bellows portion as described above, and it is therefore possible to maintain a predetermined wrapping angle.

The winding mold according to the present invention is not limited to the one shown in Fig. 3, but a split mold having a bellows shape divided in the circumferential direction is divided in the axial direction, and a spacer ring having an outer diameter larger than the trough of the bellows is inserted therein. It is preferable that the spacer insertion device be in the troughs rather than in the peaks where it may become jammed, and the width of the spacer should be more than enough to cover the bellows-shaped surface. It is preferable to make it slightly smaller and eliminate slack in the fibers. Furthermore, when the bellows has several peaks, it is difficult to distribute the slack evenly if a spacer is provided at only one location.If possible, one spacer should be provided at each pitch of the bellows. The outer diameter of the spacer ring is determined by the trough of the bellows in order to prevent the wrapped fibers from sliding sideways due to the difference in diameter between the crest of the bellows and the ring, and to prevent fibers from being caught when combining the bellows-shaped split molds. should be larger than the section.

Furthermore, the present inventors devised the following method in order to solve the problems set forth in section 1, in order to make the fibers wound using the above mold conform to the bellows shape and to make the wall thickness uniform.

That is, as shown in a specific example in FIG. 4, after removing the spacer and moving the split mold in the axial direction, the surface layer is covered at once with a rubber-like elastic body 7 having a continuous bellows shape on the inside, but as shown in FIG. As shown in the specific example shown in FIG. As shown in FIG. 4, the surface layer is covered and molded with a rubber-like elastic body having a continuous bellows shape on the inside.

According to this method, there is no mating surface on the outer mold, so
There is no problem of fiber breakage due to biting, and as the dimensional accuracy of the rubber-like elastic body is increased, the thickness can be made more uniform. It is also effective to eliminate uneven thickness by removing the resin from the outer periphery of the bellows shape, if necessary, without cutting the fibers.
Furthermore, applying pressure from the outside of the rubber-like elastic body is also effective when the matrix is viscous.

The rubber-like elastic body according to the present invention is preferably a material with appropriate elongation and excellent dimensional stability, such as a single rubber such as NBR, EPDM, silicone, or fluorine, or a rubber coating made of such rubber reinforced with cloth. Cloth etc. can be considered. Further, bellows materials to which the present invention can be applied include fiber-reinforced plastics made from a combination of reinforcing fibers such as carbon fibers, Kevlar fibers, and glass fibers, and plastics, especially thermosetting resins, particularly carbon fibers made of epoxy resin matrix. Reinforced plastics are preferred due to their high strength and high elasticity.

In the present invention, a split mold having a bellows shape divided in the circumferential direction is divided in the axial direction, and a spacer having an outer diameter larger than the valley of the bellows is inserted into the split mold, and the surface of the wrapped mold is impregnated with a matrix. The spacer ring is removed, the cylindrical shape is moved in the axial direction, and the surface layer is covered with a rubber-like elastic body having a bellows shape on the inside, or the ring-shaped rubber-like elastic body has a bellows shape on the inside. A method for manufacturing a bellows made of a fiber reinforced composite material, in which a bellows unit consisting of the following is sequentially fitted and molded in this state, or the bellows unit is once removed and the surface layer is covered with a rubber-like elastic body having a continuous bellows shape on the inside and molded. The shape of the bellows, the number of ridges, etc. are not limited to the specific examples, and its uses are wide.

[Brief explanation of drawings]

Fig. 1 and Fig. 2 are both front views of a cylindrical body with bellows, and Fig. 3 is a vertical cross-sectional view (Fig. A-A cross-sectional view (Figure b) and its B-B
The cross-sectional view (FIG. c), FIG. 4, and FIG. 5 each illustrate a vertical cross-sectional view of a specific example of molding of the method for manufacturing a bellows made of fiber-reinforced composite material according to the present invention. 1... Core type, 2... Cylindrical type, 3... Bellows-shaped split type, 4... Spacer ring, 5... Shaft, 6
... Nut, 7... Rubber elastic body having a bellows shape on the inside, 10... Cylindrical part, 20... Bellows part.

Claims (1)

[Scope of Claims] 1. A winding type in which a split mold having a bellows shape divided in the circumferential direction is further divided in the axial direction, and a spacer ring having an outer diameter larger than the trough of the bellows is inserted therein. After wrapping continuous fibers impregnated with a matrix around the surface, the spacer ring is removed and the split mold is moved in the axial direction, and the surface layer is covered and molded with a rubber-like elastic body having a continuous bellows shape on the inside. A method for manufacturing a bellows made of fiber-reinforced composite material, characterized by: 2 Claim 1 using a winding mold in which a split mold having a bellows shape is divided at the troughs of the bellows
A method for manufacturing a bellows made of a fiber reinforced composite material as described in 2. 3 Place the split mold having a bellows shape into one of the bellows parts.
A method for producing a bellows made of a fiber reinforced composite material according to claim 1, using a winding mold divided into pitches in the axial direction. 4. The method for producing a bellows made of fiber reinforced composite material according to claim 1, 2 or 3, wherein the fiber reinforced composite material is carbon fiber reinforced plastics. 5 A split mold having a bellows shape divided in the circumferential direction is further divided in the axial direction, and a spacer ring having an outer diameter larger than the valley of the bellows is inserted into the split mold, and the surface of the wrapped mold is impregnated with a matrix. After winding the continuous fibers, the spacer ring is removed, the split mold is moved in the axial direction, and a bellows unit made of a ring-shaped rubber-like elastic body with a bellows shape inside is sequentially fitted into the valley. 1. A method for producing a bellows made of fiber reinforced composite material, characterized in that the bellows unit is once removed and the surface layer is covered with a rubber-like elastic body having a continuous bellows shape on the inside and then molded. 6 Claim 5 using a winding mold in which a split mold having a bellows shape is divided at the troughs of the bellows
A method for manufacturing a bellows made of a fiber reinforced composite material as described in 2. 7 Place the split mold having a bellows shape into one of the bellows parts.
A method for producing a bellows made of fiber reinforced composite material according to claim 5, which uses a winding mold divided into pitches in the axial direction. 8. The method for manufacturing a bellows made of fiber reinforced composite material according to claim 5, 6 or 7, wherein the fiber reinforced composite material is carbon fiber reinforced plastics.