JPH05164115A - Joint structure for fiber reinforced plastic pipe - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention makes use of the characteristics of FRP having excellent specific strength and specific rigidity to the maximum extent, and provides a reliable fiber-reinforced plastic pipe as a structural member that exerts a large force on the joint. An object is to provide a joint structure. [Structure] A fiber-reinforced plastic pipe is provided with an outward-opening tapered joint portion at least at one end portion thereof, and a metallic split outer joint having an inner surface inclined substantially the same as the taper and screwed to the outer joint to form the taper The taper portion of the fiber reinforced plastic joint portion is inserted into the gap formed by the inner peripheral surface and the outer peripheral surface of the metal inner joint having substantially the same inclined outer surface as described above, and is clamped and fixed by both the inner and outer joints. The gist is a joint structure of a fiber-reinforced plastic pipe characterized by.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure when a pipe made of fiber reinforced plastic made of carbon fiber or the like is used as a structural member.

[0002]

2. Description of the Related Art Since fiber reinforced plastics (hereinafter referred to as FRP) have high strength, excellent corrosion resistance, and light weight, they have taken advantage of these characteristics and have advanced to many fields including metal usage fields. For example, CFRP (carbon fiber reinforced plastic) has a wide range of uses such as outer plates of aircrafts and space rockets, and sports and leisure fields such as golf club shafts and fishing rods. Recently, pipe forming technology has advanced and attempts have been made to use it for rotary shafts, transportation pipes, etc. However, when using a pipe as a member for machine structure, the problem is the reliability of the joint portion. Conventional FRP pipe members cannot be welded and are weak to joining with bolts. Further, in the method in which the joint portion is threaded to be joined, the strength is remarkably lowered because the reinforcing fiber is cut by the thread cutting. Therefore, it cannot be applied to structural materials.

In order to solve such a problem, in the rear of Japanese Patent Laid-Open No. 63-13996, a joint metal fitting having a taper portion for converting an axial force into a circumferential force is provided at the end of an FRP member by a filament winding method. A fitted joint structure is disclosed. However, in such a structure in which a metal fitting having a special shape is wound, the manufacturing process is complicated and workability is poor.

Further, in Japanese Patent Laid-Open No. 63-242523, a layer formed by impregnating a resin into a fiber reinforced woven fabric in which fibers are oriented in a three-dimensional direction is formed on the outer circumference of a FRP pipe and machined after the resin is cured. A method of manufacturing a joint part that is threaded with a screw has been proposed. However, this method requires manufacturing steps such as manufacturing of a three-dimensional woven fabric, resin impregnation, and curing, which increases the manufacturing cost.Although the reinforcing fiber is specially woven, it has a screw structure, so the strength of the joint does not decrease. I cannot escape.

Further, Japanese Patent Application Laid-Open No. 1-126412 describes that an FRP layer is formed on the outer periphery of a mandrel having tapered ends, and the mandrel is pulled out to manufacture a transmission shaft pipe having tapered ends. It is described that the tapered portion of this pipe is bonded to a steel joint element with an adhesive to form a transmission shaft. It is difficult for a joint portion joined with such an adhesive to withstand a high load, and reliability is poor.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned conventional problems, and makes the most of the characteristics of FRP having excellent specific strength and specific rigidity,
An object of the present invention is to provide a reliable joint structure for a fiber-reinforced plastic pipe as a structural member that is subjected to a great amount of axial tension and compression at the joint.

[0007]

In order to achieve the above object, the present invention is directed to a metal having an outwardly opening tapered joint portion formed on at least one end of a fiber reinforced plastic pipe and having an inner surface inclined substantially the same as the taper. Of the fiber-reinforced plastic pipe in the gap formed by the inner peripheral surface and the outer peripheral surface of the split outer joint made of metal and the inner joint made of metal that is screwed to the outer joint and has an outer surface that is substantially the same as the taper. A gist of a joint structure of a fiber reinforced plastic pipe is characterized in that a taper portion of the joint portion is inserted and sandwiched and fixed by both inner and outer joints.

In the above invention, a fiber-reinforced plastic joint is inserted into the gap between the outer joint and the inner joint, leaving a position slightly apart from the taper start point thereof, so that it is incorporated into a larger structural member. Is effective if Further, the inner surface of the taper portion of the fiber reinforced plastic joint portion inserted in the gap between the outer joint and the inner joint may be in contact with the inner joint in a range of at least 50%, not necessarily the entire surface. Furthermore, in the above joint structure,
The joint strength can be further increased by tightening and supporting the tip end portion of the outer joint with the tightening ring, which is also one of the features of the present invention. In addition, in the joint structure of the present invention, the outer joint can be fixed to the sleeve and can be incorporated into the structure through the outer joint.

[0009]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. 1 is a side view of an embodiment of the present invention, FIG. 2 is a transverse sectional view taken along the line AA of FIG. 1, FIG. 3 is a longitudinal sectional view taken along the line BB of FIG. 1, and FIG. 4 is another embodiment of the present invention. FIG. 5 is a vertical sectional view showing an example, and FIG. 5 is a horizontal sectional view showing another embodiment of the present invention.

In FIGS. 1 to 3, reference numeral 1 is an FRP pipe, and a joint portion 10 (hereinafter also simply referred to as a taper portion 10) having a taper portion whose diameter is expanded outward is provided at an end portion thereof. Reference numeral 2 denotes a metal outer joint, which is composed of two or more divided pieces, and in the example of the drawing, two divided pieces 21a and 22b are provided as shown in FIGS. Each divided piece 2
The inner peripheral surfaces 1a and 21b have substantially the same inclined (tapered) surface 20 so as to match the outer surface of the tapered portion 10 of the FRP pipe joint portion. A thick portion 23 having a step 22 on the inner surface is formed at the rear end portion of the outer joint 2, and a female screw is cut on this portion. 24 is each divided piece 21a, 21
A connecting ring is provided on the rear end face of b as needed to connect them.

Reference numeral 3 is a metal inner joint, the outer peripheral surface of which is F
It has almost the same inclined (tapered) surface 30 so as to match the inner surface of the tapered portion 10 of the RP pipe joint portion, and a thick portion 32 having a step 31 is formed on the outer surface of the rear end portion thereof, and a male screw is formed in this portion. It has been cut. In the illustrated example, the inner and outer joints are provided with the wall thicknesses 23 and 32, but the present invention is not limited to this, and they may be installed only in one joint, that is, as long as the gap 5 can be formed between both joints. Reference numeral 33 is a knob for tightening which is attached via an end plate 34 provided on the rear end surface of the inner joint 3. The inner joint 3 has the tapered portion 10
Although it is preferable that the inner joint 3 is in contact with the entire inner circumference, the present invention is not limited to this, and the inner joint 3 may be configured so as to contact a part of the peripheral surface of the tapered portion 10 as shown in FIG. 4, for example. However, in this case, the contact surface of the inner joint must be 50% or more of the inner circumference of the tapered portion 10.

The outer joint 2 is screwed and fixed to a sleeve 4 to be incorporated in a structure. On the other hand, the inner joint 3 and the outer joint 2 are screwed and fixed with screws engraved in the end thick portions 32 and 23, respectively, and the joint tapered portions 31 and 20 are also provided.
The taper portion 10 at the end portion of the FRP pipe inserted into the gap 5 formed by is clamped and supported. 6 is a tightening ring,
It is provided to fit the tip portion of the outer joint 2 to prevent the joint from loosening and to apply a tightening force so that the outer / inner joint surface and the surface of the FRP pipe 1 come into closer contact. The outer circumference of the tip of the outer joint 2 and the inner circumference of the tightening ring 6 may be tapered so that they can be easily fitted to each other. In the figure, 7 is a structure for connecting the joint structure of the present invention, and 8 is a connecting bolt.

FIG. 5 shows another embodiment of the present invention, in which the split type outer joint 2 and the inner joint 3 support the tapered joint portion 10 of the FRP pipe 1, and the tightening ring 6 is provided at the tip of the outer joint 3. The basic configuration provided with is the same as the configuration of FIGS. 1 to 4 described above (thus, the same reference numerals are used for the same portions as those in the above respective drawings, and the description thereof will be omitted). In this embodiment, the diameter of the end plate 34 provided on the end face of the inner joint 3 is made larger than the outer diameter of the inner joint 3 by the amount of forming the gap 5, and the outer periphery of the end plate 34 of the outer joint 2 is formed. While fixing to the inner circumference with screws, etc., F
The end surface of the RP pipe joint portion 10 is supported. Reference numeral 9 denotes a locking projection provided on the outer joint 3 immediately before that in order to prevent the tightening ring 6 from moving (falling off), and a bolt is used in the illustrated example. Such a locking projection 9 can be applied to each of the embodiments shown in the above figures. Reference numeral 81 is a connecting pin used in place of the connecting bolt 8 in the case of FIG.

In the embodiments shown in the above figures, the inner joint, the outer joint and the sleeve are joined by screws. However, the present invention is not limited to this, and bolts or means such as welding may be used. be able to. The same applies to joining with the structure 7.

The present invention has the above-described structure, and when the FRP pipe 1 is incorporated into a structure, for example, the joint portion 1 of the pipe is used.
After inserting 0 into the outer joint 2 consisting of split pieces, the inner joint 3
Is inserted into the pipe 1 while being screwed with the outer joint 2, and the taper portion 10 of the pipe 1 is formed by the inner circumference of the outer joint 2 and the outer circumference of the inner joint 3.
The taper portion 10 is positioned in the gap 5 formed at an interval equal to or slightly smaller than the wall thickness of, and is fixed to the sleeve 4 and then tightly contacted and sandwiched with both joints. The outer joint is a rigid body made of metal, but since it is divided into a plurality of pieces, the tip opening can be enlarged and insertion into the tapered portion 10 can be facilitated. The tips of the inner and outer joints 2 and 3 are preferably located slightly away from the taper start point of the pipe 1. That is, if the joint tip is located at or near the taper start point, stress concentration is likely to occur at the taper start point and there is a risk of damage. FRP sandwiched between both joints 2 and 3
Since the pipe joint portion 10 is formed in a tapered shape, the frictional resistance is extremely large, and the pipe joint portion 10 is not pulled out even if a force from the structure, that is, an excessive tensile force is transmitted. However, if the taper angle is too small, pull-out occurs, and if it is too large, the inner and outer joints must be made large, which is disadvantageous. Therefore, the range of 5 to 20 degrees is preferable.

Further, by fitting the tightening ring 6 to the tip portion of the split outer joint 2, the split piece is prevented from opening even when a large load is applied, and the tight contact with the pipe joint portion is further improved. Is possible. At this time, if the locking protrusion 9 is provided, the tightening ring 6 can be prevented from falling off, and the practical effect can be enhanced.

Further, in order to make the contact between the FRP pipe joint portion 10 and both joints more tight and to evenly transmit the force, a resin layer is provided at the contact portion as necessary, for example, the joint portion 1
It is effective to apply the resin to the outer surface, the inner surface, or both of them.

As the FRP fiber material used in the present invention,
Carbon fiber, black smoke fiber, glass fiber, inorganic fiber of silicon carbide sugar, or aromatic polyamide fiber, there are organic fibers such as aromatic polyester fiber, and as the resin to be used, epoxy resin, unsaturated polyester resin, There are thermosetting resins such as phenol resin and polyimide resin, and thermoplastic resins such as polysulfone resin and polycarbonate resin. These fibers and resins can be combined as needed.

The present invention as described above is extremely effective when a FRP is used as a member for various structures, particularly for a joint as a brace material for a building.

[0020]

As described above, according to the present invention, the joint portion of the FRP pipe is formed in a tapered shape and clamped and supported by the metal joint, so that a joint structure having extremely high supporting strength can be obtained. It can be extremely suitable as a structural member, and its application range can be expanded.

[Brief description of drawings]

FIG. 1 shows a side view of the present invention.

FIG. 2 shows a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a vertical sectional view taken along line BB of FIG.

FIG. 4 shows a vertical sectional view of another example of the present invention.

FIG. 5 shows a cross-sectional view of another example of the present invention.

[Explanation of symbols]

 1: FRP pipe 10: Joint part (tapered part) 2: Outer joint 20: Inclined surface (tapered surface) 21: Divided piece 22, 31: Step 23, 32: Thick part 24: Connection ring 3: Inner joint 33: Knob 34: End plate 4: Sleeve 5: Gap 6: Tightening ring 7: Structure 8: Connection bolt 81: Pin 9: Locking protrusion

[Procedure amendment]

[Submission date] September 18, 1992

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

[0003] In order to solve such problems, the FRP member end in JP-A-63-13996, by a filament winding method a joint hardware having a tapered portion for converting an axial force in the circumferential direction of the force A fitted joint structure is disclosed. However, in such a structure in which a metal fitting having a special shape is wound, the manufacturing process is complicated and workability is poor.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

As the FRP fiber material used in the present invention,
Carbon fiber, black lead fibers, glass fibers, inorganic fibers such as silicon carbide, or aromatic polyamide fibers, aromatic polyester
There are organic fibers such as fibers, and as the resin to be used, there are thermosetting resins such as epoxy resin, unsaturated polyester resin, phenol resin and polyimide resin, and thermoplastic resins such as polysulfone resin and polycarbonate resin. These fibers and resins can be combined as needed.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Kenji Kubomura 1618 Ida, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Nippon Steel Corporation Advanced Technology Research Laboratories

Claims (4)

[Claims] 1. A split outer joint made of metal, which comprises an outward-opening tapered joint portion at least at one end portion of a fiber reinforced plastic pipe and has an inner surface inclined substantially the same as the taper.
The taper portion of the joint portion of the fiber-reinforced plastic pipe is inserted into the gap formed by the inner peripheral surface and the outer peripheral surface of the metal inner joint which is fixed to the outer joint and has the same inclined outer surface as the taper. Then, the joint structure of the fiber reinforced plastic pipe is characterized in that it is sandwiched between both the inner and outer joints and the tip of the outer joint is supported by a tightening ring. 2. A joint for a fiber-reinforced plastic pipe according to claim 1, wherein a joint portion made of a fiber-reinforced plastic is inserted into a gap between the outer joint and the inner joint to a position slightly separated from a taper start point thereof. Construction. 3. At least 5 is formed on the inner surface of the taper portion of the fiber reinforced plastic joint portion inserted into the gap between the outer joint and the inner joint.
The joint structure for a fiber-reinforced plastic pipe according to claim 1, wherein the inner joint is brought into contact with the glass in an amount of 0%. 4. The joint structure for a fiber reinforced plastic pipe according to claim 1, wherein the outer joint is fixed to the sleeve.