JPH07112714B2 - Fiber-reinforced composite material truss joint and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fiber-reinforced composite material truss joint for joining truss members such as a space truss structure and a manufacturing method thereof.

[Conventional technology]

As space structures such as artificial satellites and space stations,
BACKGROUND ART A truss structure is used in which truss members made of pipes made of fiber reinforced plastic (hereinafter referred to as FRP) such as carbon fiber reinforced plastic (hereinafter referred to as CFRP) are joined by truss joints and assembled.

FIG. 10 is a perspective view showing a conventional truss joint. In the figure, (1) is a truss joint, and a truss member insertion hole (a) is formed at the tip of each cylindrical body (2) of the radial body (3) from which the cylindrical bodies (2) project radially in a plurality of axial directions. 4) is formed, and the whole is formed of a lightweight metal such as aluminum. (5) is a truss member, which is made of FRP pipe such as CFRP, is arranged in a plurality of axial directions, is inserted into the truss member insertion hole (4) and is joined, and the truss structure is assembled. .

In the above-mentioned truss joint (1), the truss structure (5) is formed by inserting the truss member (5) into the insertion hole (4) and fixing it with an adhesive or a pin. In this state, the tensile force and the compressive force acting on the truss member (5) are transmitted by the truss joint (1).

[Problems to be Solved by the Invention]

However, in the conventional truss joint as described above,
CFRP, which is the truss member (5), has a small specific gravity of 1.4 to 1.5, a high specific strength (strength per specific gravity) and a high specific rigidity suitable for space structural members, and the fibers are oriented in the load direction to reduce the weight. Although it is exposed, the truss joint (1)
Since it is made of aluminum, its specific gravity is as large as 2.7, its specific strength and rigidity are low, the weight of the joint is large, which leads to an increase in the weight of the object to be launched at the time of launch from the ground, and the thermal expansion coefficient of aluminum is CFRP. However, there was a problem that the internal stress was generated due to temperature fluctuation.

The present invention has been made to solve the above problems, and has a specific strength and specific rigidity equivalent to those of a truss member for weight reduction, and has a small thermal expansion coefficient to be closer to the truss member. An object of the present invention is to provide a fiber-reinforced composite material truss joint capable of preventing the generation of internal stress and a method for manufacturing the same.

[Means for Solving the Problems]

The present invention is the following fiber-reinforced composite material truss joint and its manufacturing method.

(1) In joints of truss members made of lightweight pipe,
A short rod made of continuous fiber-reinforced composite material, which is incorporated by radially intersecting in the plurality of axial directions so as to face the ends of the plurality of truss members arranged in the plurality of axial directions, and the outer circumference of the short rod. Of a plurality of long rods made of continuous fiber reinforced composite material, which is incorporated into a truss member to form a truss member insertion hole at its tip, and a fiber reinforced composite member inserted in the inner peripheral portion of the truss member insertion hole. An inner pipe made of a material and an outer pipe made of a continuous fiber reinforced composite material formed on the outer peripheral portion of the long rod facing the inner pipe are provided, and the entire gap of the short rod and the long rod is provided. A fiber-reinforced composite truss joint characterized in that is substantially filled with a matrix layer and is wholly integrated.

(2) A plurality of short rods made of continuous fiber-reinforced composite material are installed by intersecting in a plurality of axial directions, and a plurality of long rods made of continuous fiber-reinforced composite material are incorporated in the outer peripheral portion of this short rod to make the tip end. To form a radial body having a truss member insertion hole, to join an inner pipe to the inner peripheral portion of the truss member insertion hole, and to wind continuous fibers around the outer peripheral portion of the long rod facing the inner pipe. Attaching and impregnating and curing the matrix to form the outer pipe, and inserting the formed preform into the mold to inject the matrix, and the entire gap between the short rods and the long rods is formed by the matrix layer. A method of manufacturing a truss joint made of a fiber-reinforced composite material, which comprises a step of substantially filling and integrating the whole.

[Work]

The fiber-reinforced composite material truss joint of the present invention incorporates a plurality of continuous fiber-reinforced composite material short rods intersecting in a plurality of axial directions, and a plurality of continuous fiber-reinforced composite material outer peripheral portions of the short rods. A long rod is incorporated to form a radial body having a truss member insertion hole at the tip, an inner pipe is joined to the inner peripheral portion of the truss member insertion hole, and the outer peripheral portion of the long rod faces the inner pipe. The continuous pipe is wound around and the matrix is impregnated and cured to form the outer pipe, and the formed preform is inserted into the molding die and the matrix is injected, and the entire gap between the short rods and the long rods is filled. Manufactured by substantially filling with a matrix layer to integrate the whole.

In the truss joint manufactured in this manner, the truss member is inserted into the truss member insertion hole and fixed by an adhesive or pinning to form a truss structure. In this state, the tensile force, compressive force, stress, torsional force, etc. acting on the truss member are transmitted by the truss joint.

〔Example〕

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

1 is a perspective view showing a truss joint of an embodiment, FIG. 2 is a front view thereof, FIG. 3 is a sectional view taken along line AA of FIG. 4, FIG. 4 is a perspective view showing an intersection of rods, and FIG. FIG. 6 is a perspective view showing a radial body, FIG. 6 is a sectional view taken along the line BB, FIG. 7 is a perspective view showing an outer pipe forming step, and FIG. 8 is a sectional view taken along the line CC.
FIG. 9 is a cross-sectional view showing the forming die, and in the figure,
The same reference numerals as those in the drawings indicate the same or corresponding parts.

The truss joint (1) has a truss member insertion hole (4) at the tip of each cylindrical body (2) of the radial body (3) from which the cylindrical body (2) radially projects in a plurality of axial directions. The truss joint (1) is formed of a fiber-reinforced composite material, which is different from the conventional one, although it is formed similarly to the conventional one.

(11) is a plurality of continuous fiber reinforced composite materials that are assembled by radially intersecting a plurality of axial directions so as to face the ends of a plurality of truss members (5) arranged in a plurality of axial directions. The short rods (12) are a plurality of long rods made of continuous fiber reinforced composite material, which are incorporated in the outer peripheral portion of the short rod (11) and form a truss member insertion hole (4) at the tip thereof, The body (3) is formed by these short rods (11) and long rods (12). (13) is an inner pipe made of fiber reinforced composite material inserted in the inner peripheral portion of the truss member insertion hole (4) formed by the long rod (12), and (14) is opposed to this inner pipe (13) The outer pipe made of continuous fiber reinforced composite material formed on the outer peripheral portion of the long rod (12), and (15) fills the entire gaps of the short rod (11) and the long rod (12). It is a matrix layer that integrates the entire structure.

The short rods (11) and the long rods (12) are formed in a rod shape, with continuous fibers (16) such as carbon fibers oriented in the longitudinal direction, and a matrix (17) such as resin filling the gap. The diameter of 0.5 to 1 mm can be used.
The radial body (3) is formed in a radial shape by incorporating such short rods (11) and long rods (12) in a stab-like manner in a plurality of axial directions, as shown in FIG. . The inner pipe (13) is a continuous fiber (1
6) are oriented so that they intersect each other at an angle of 45 ° with respect to the axial direction, and a matrix (17) of resin or the like fills the gap and is formed in a pipe shape. ) Is fixed to the inner circumference of the tip of each cylindrical body (2). The outer pipe (14) is made by winding continuous fiber (16) such as carbon fiber impregnated with a matrix (17) such as resin so that it is oriented in the direction of 90 ° to the axial direction, tightening and hardening it. It is formed into a shape. The matrix layer (5) is filled in the gaps between the rods (11) and (12) as well as in the gaps between the rods (11) and (12) and other members so as to be integrated as a whole.

The method for manufacturing the above-mentioned truss joint (1) includes a plurality of short rods (11) made of continuous fiber reinforced composite material, which are assembled by intersecting radially in a plurality of axial directions as shown in FIG. Multiple long rods made of continuous fiber reinforced composite material (1
2) is incorporated to form a radial body (3) having a truss member insertion hole (4) at its tip as shown in FIGS. 5 and 6.

Then, as shown in FIG. 8, the truss member insertion hole (4)
A thin inner pipe (13) with a thickness of 0.5 to 1 mm on the inner circumference of the
The inner pipe (13)
Insert the holding plug (21) into the and screw the mandrel (22).

Subsequently, as shown in FIG. 7, while rotating the mandrel (22), the continuous fiber roving (23) such as carbon fiber impregnated with the matrix (17) such as resin is attached to the carriage eye arm (24). It is supplied from the eye (26) through the supported guide roll (25), and the continuous fiber roving (23) is wound around the outer periphery of the long rod (12) so as to face the inner pipe (13). Wind the length rod (12) and harden the matrix (17) such as resin to fix the outer pipe (1
4) to form.

As shown in FIG. 9, the preform body (27) thus formed, with the holding plug (21) attached, has a cavity (29) of a two-part or four-part mold (28). ), And through the injection runner (31) from the injection port (30),
Cavity (29) for the matrix of vacuum degassed resin
To the space between the short rods (11) and the long rods (12), and the matrix layer (15) free from air bubbles is discharged from the discharge port (32) through the discharge runner (33). The entire space between the rods (11) and (12) and other members such as the inner pipe (13) is filled, and the whole is fixed and integrated to complete the truss joint (1).

In the truss joint (1) manufactured in this way, the truss member (5) is inserted into the truss member insertion hole (4) and fixed by an adhesive or a pinning to form a truss structure.
In this state, the tensile force, the compressive force acting on the truss member (5),
Stress, torsional force, etc. are transmitted by the truss joint (1).

At this time, the tensile force, compressive force, stress, torsional force, etc. from the truss member (5) are passed through the inner pipe (13) bonded to the truss member (5) and the rod (11) made of the continuous fiber reinforced composite material. , (12) is transmitted in the axial direction and receives a load. Since the outer pipe (14) is fixed by winding the continuous fiber roving (23) around the pipe outer periphery of the continuous rod (12) made of continuous fiber reinforced composite material in a direction perpendicular to the axial direction, Retain 12) like a pipe and reinforce it.

In addition, the preform body (27) is inserted into the molding die (28) to inject the matrix, and the whole of the gap between the rods (11) and (12) and the gap between the rods (11) and (12) and other members. Since the matrix layer (15) is formed and integrated as a whole, not only tensile force and compression force but also stress, torsional force, etc. can be transmitted, and the truss joint (1) having high rigidity can be obtained.

Although carbon fibers are used as the continuous fibers (16) in the above embodiments, other fibers such as glass fibers and aramid fibers may be used. Further, although the resin is used as the matrices (15) and (17), when it is used for heat resistance, it may be a metal such as aluminum or magnesium, and the same effect as that of the above-mentioned embodiment is obtained.

〔The invention's effect〕

As described above, according to the present invention, the short and long rods made of continuous unidirectional fiber-reinforced composite material that are continuous in the axial direction of each shaft are arranged in a pipe shape, and the inner portion is inserted inside the truss member insertion hole. The pipe and the continuous fiber roving are arranged on the outside in the direction perpendicular to the axis, and the gap between the short rods and the gap between the long rods are substantially filled with the matrix layer to integrate the whole, so that it is lightweight and rigid. Has a high mechanical strength and can transmit tensile force and compressive force in the axial direction, as well as stress and torsional force, and since it is the same material as the truss member, it has the same coefficient of thermal expansion and prevents the generation of internal stress. There is an effect that an inexpensive truss joint can be obtained.

[Brief description of drawings]

1 is a perspective view showing a truss joint of an embodiment, FIG. 2 is a front view thereof, FIG. 3 is a sectional view taken along line AA of FIG. 4, FIG. 4 is a perspective view showing an intersection of rods, and FIG. FIG. 6 is a perspective view showing a radial body, FIG. 6 is a sectional view taken along the line BB, FIG. 7 is a perspective view showing an outer pipe forming step, and FIG. 8 is a sectional view taken along the line CC.
FIG. 9 is a sectional view of the forming die, and FIG. 10 is a perspective view showing a conventional truss joint. In the drawings, the same reference numerals indicate the same or corresponding parts, and (1)
Is a truss joint, (2) is a cylindrical body, (3) is a radial body,
(4) truss member insertion hole, (5) truss member, (1
1) is a short rod, (12) is a long rod, (13) is an inner pipe, (14) is an outer pipe, (15) is a matrix layer, (16) is a continuous fiber, (17) is a matrix,
(22) is a mandrel, (23) is continuous fiber roving,
(27) is a preform body, and (28) is a forming die.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location E04B 1/58 M 8913-2E F16L 41/03 // B29K 105: 06 B29L 22:00 (72) Inventor Sugano Toshiyuki 8-1-1 Tsukaguchihonmachi, Amagasaki-shi, Hyogo Sanryo Electric Co., Ltd. Materials Research Laboratory (72) Inventor Hasegawa Hikaru 325 Kamimachiya, Kamakura-shi, Kanagawa Mitsubishi Electric Co., Ltd. Kamakura Manufacturing (72) Inventor Hiroko Soko 325 Kamimachiya, Kamakura City, Kanagawa Mitsubishi Electric Corporation, Kamakura Factory (72) Inventor Toshio Inoue 325, Kamimachiya, Kamakura City, Kanagawa Mitsubishi Electric Corporation, Kamakura Factory (56) Reference JP 60-179238 (JP) , A) JP 61-155531 (JP, A) JP 61-155532 (JP, A)

Claims (2)

[Claims] 1. A joint for a truss member made of a light-weight pipe, which is continuously assembled so as to radially intersect in a plurality of axial directions so as to face the ends of a plurality of truss members arranged in a plurality of axial directions. A plurality of short rods made of fiber reinforced composite material, and a radial body composed of a plurality of long rods made of continuous fiber reinforced composite material, which is incorporated in the outer peripheral portion of the short rod to form a truss member insertion hole at the tip thereof. An inner pipe made of a fiber reinforced composite material inserted into an inner peripheral portion of the truss member insertion hole, and an outer pipe made of a continuous fiber reinforced composite material formed on an outer peripheral portion of a long rod facing the inner pipe. The gap between the short rods and the gap between the long rods are substantially completely filled with a matrix layer, and the whole is integrated with each other. Lath fitting. 2. A plurality of short rods made of a continuous fiber reinforced composite material are assembled so as to intersect with each other in a plurality of axial directions, and a plurality of long rods made of a continuous fiber reinforced composite material are incorporated in the outer peripheral portion of the short rods. A step of forming a radial body having a truss member insertion hole at its tip, a step of joining an inner pipe to the inner peripheral portion of the truss member insertion hole, and a continuous fiber on the outer peripheral portion of the long rod facing the inner pipe. The process of winding and precipitating and hardening the matrix to form the outer pipe, and inserting the formed preform into the mold and injecting the matrix, the entire gap between the short rods and the long rods is formed into the matrix. Substantially filled with layers,
A method for manufacturing a truss joint made of fiber-reinforced composite material, which comprises a step of integrating the whole.