JPS61244535A - Manufacture of grid structure - Google Patents

Abstract

PURPOSE:To obtain a gird structure having an adequate strength by laminating various prepregs in one bottom force of a die, pressing the prepregs into a shape with the other top force, and forming a grid structure through curing process applied to the prepregs. CONSTITUTION:Prepregs B1 for linkage corresponding to a connexion, a frame and a crosspiece are arranged in a circumferential direction so that they may be laid in each groove 11a, 11b. Prepregs B3 for linkage corresponding to the connexion and part of the crosspiece, and prepregs A1 for the frame cut to a proper size are laminated. Processes following these two processes are alternately carried out several times. The fiber direction of the frame 101 is divided into a circumferential direction of the frame 101 and a direction at right angles with the former. In addition, the layer of the flange 101a integrally formed is formed in a state that it is overlapped with almost an axial direction of said grid structure G. Thus an adquate strength can be obtained against a load in a compression direction and also a load in a tensile direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a grid structure made of fiber-reinforced plastic.

(Prior Art) Generally, as a grid structure made of fiber reinforced plastic (FRP), there is one shown in FIG. 10, for example.

That is, the cylindrical triangular grid structure G shown in the figure has a large number of crosspieces 10 between two ring-shaped frames 101, 101.
It is used as a joint between the kick motor in the core structure of a satellite or the top stage of a rocket and the lower rocket motor, and is made of carbon fiber. Fiber-reinforced plastic (CFRP) is used.

The above-mentioned grid structure G has conventionally been manufactured based on a filament winding method. This involves forming a groove corresponding to the shape of the grid structure G on the outer periphery of a cylindrical core using a removable jig, and inserting continuous resin-impregnated carbon fiber filaments into the groove of the rotating core. It is wrapped while applying a constant tension. Further, after winding is completed, an initial heat curing treatment is performed, and then the jig is removed and the hardened grid structure is removed. In addition, as a specific example of the manufacturing method using the filament winding method, for example, Japanese Patent Application Laid-open No. 178830/1983 is known.

(Problems to be Solved by the Invention) However, in the method for manufacturing a grid structure as described in "-", since the method involves winding continuous carbon fiber filaments one after another, the core shown in FIG. As shown in part, between the filament F wound from the crosspiece groove 103 to the frame groove 104 and the filament L-F wound from the frame groove 104 to another crosspiece groove 103. On the other hand, a portion 105a where the fibers are sparse is created, and on the other hand, a crossing portion 105b of the filaments F is created, so there is a problem that the fiber content differs significantly in some parts, which is unfavorable in terms of strength. There was a problem in that it was not possible to provide proper reinforcement. Furthermore, as shown in FIG. 12, the frame 101 of the grid structure is often provided with a flange 101a for attaching a clamp band, port/nut, etc. used for connection with other structures. However, as described above, in addition to the portion 105a where the fibers are sparse, the fiber direction of the filaments F in the frame portion 101 is all circumferential, so the strength against tensile load is particularly low near the flange portion 101a. There was a problem that the

This invention was made by focusing on the two-fold problem, and solves the problems such as partial fiber sparsity, partial inability to reinforce, and lack of strength against tensile loads, and improves overall fiber density. It is an object of the present invention to provide a method for manufacturing a grid structure that can obtain a grid structure having sufficient strength.

"Structure of the Invention" (Means for Solving Problems) The method for manufacturing a grid structure according to the present invention will be explained based on FIG. In this method, various prepreg materials having a certain fiber direction and corresponding to each part of the silica grid structure, such as the frame, the crosspiece, and the connection between the frame and the crosspiece, are laminated in one mold. Thereafter, in step 2, the prepreg material is pressed and shaped using the other mold, and then in step 3, the prepreg material is subjected to a curing treatment to form a grid structure. Also,
The above prepreg material is made by forming fiber bundles such as carbon #li fiber filaments into a cloth shape in a certain fiber direction, impregnating this with a thermosetting resin mixed with a hardening agent and filler, and drying it. In the case of the above structure, in order to prevent the seams of prepreg materials in different parts from overlapping during lamination, it is more desirable to use several prepreg materials with different sizes for one part.

(Example) The present invention will be explained below based on the drawings.

FIGS. 2 and 3 are diagrams illustrating an apparatus used in an embodiment of the method for manufacturing a grid structure according to the present invention.

That is, the device shown in the figure is used to manufacture a cylindrical triangular grid structure (see FIG. 10), and reference numeral 5 denotes a device having a cylindrical shape and rotatably held by a shaft 6. A female mold is formed on the outer periphery of the core 5 as one mold corresponding to the shape of the grid structure. Furthermore, in forming the female mold, two rings 8, 8 are fitted onto the core 5 with a splittable cylindrical member 7 in between, and a large number of triangular jigs are placed on the surface of the cylindrical member 7. 9
By fixing them with bolts 10, respectively, a frame groove 11a corresponding to the frame of the grid structure is formed between the ring 8 and the jig 9, and a crosspiece of the grid structure is formed between each jig 9. Further, each ring 8 has a male frame part 12 as the other mold which forms a frame part with a flange between it and the ring 8.
(part of which is shown in the figure) is removably provided with a pole) 12a, and on the outer circumferential side of each jig 9, there is a same plate that forms a crosspiece between the jig 9 and the cylindrical member 7. A male mold 13 (partially shown in the figure) for the crosspiece as the other mold is removably provided. The male die 13 for the crosspiece can be accessed by a port 13a which is inserted through the jig 9 and screwed into the cylindrical member 7, with a spacer 14 interposed between it and each jig 9. Each male mold 12, 13 is divided into several parts.

FIGS. 4(a) to 4(h) are diagrams for explaining types of prepreg materials.

Prepreg material is made by impregnating a carbon fiber mat with a certain fiber direction with a thermosetting resin and drying it.
Broadly speaking, they are divided into prepreg material A for the frame portion, prepreg material B for the connecting portion used near the connecting portion between the frame portion and the crosspiece portion, and prepreg material C for the crosspiece portion.

The prepreg material A for the frame has a fiber direction along the circumferential direction of the frame, and as shown in FIG. 4(a), there is a prepreg material A1 corresponding only to the frame, and a As shown in b), prepreg material A corresponding to a part of the frame part and the connecting part
2, and may be cut into appropriate dimensions for use.

The prepreg material B for the connection part has a fiber direction along the axial direction of the grid structure, and as shown in FIGS. As shown in FIG. 4(e), prepreg materials B1 and B2 correspond to the connecting portion and a part of the crosspiece, prepreg material B3 corresponds to a part of the connecting portion, prepreg material B4 corresponds to a part of the connecting portion, as shown in FIG. As shown in (f), there is a prepreg material B5 corresponding to a part of the connecting part and the frame part. In addition, the prepreg material B for the connecting part is
For example, even if the prepreg materials Bl and B2 corresponding to the connecting part, the crosspiece, and a part of the frame are similar in form, the parts corresponding to the frame may be shifted in opposite directions, or the prepreg materials corresponding to the crosspiece may be similar. There are several types of prepreg materials, including those with different length dimensions (shown in FIG. 4(d)).

The prepreg material C for the crosspiece has a strip shape with the fiber direction mainly along the longitudinal direction, and as shown in FIGS. 4(g) and (h), various prepreg materials are cut into appropriate lengths. Material 0
There are 1 to C4. In addition, as shown in FIGS. 4(e) and 4(f), the prepreg materials C for the crosspieces include prepreg materials C5 and CB that also correspond to a part of the connecting portion, and these prepreg materials C5 and C6 are The end portions are bent so that the fiber direction at the connecting portion coincides with the axial direction. In addition.

The length of each of the prepreg materials 01 to C6 for the crosspieces described in Section 7 can be set depending on the dimensions of the prepreg material B for the connecting portion, and as is clear from the illustration, the prepreg material for the connecting portion may vary depending on the cutting dimensions. It can also be used as material B.

FIGS. 5(a) to 5(q) and FIG. 6 are diagrams illustrating an example of the lamination process of the prepreg materials A, B, and C.

In each figure, the reference numeral 9 is a jig fixed to the core 5 (see FIG. 2), 11a is a groove for a frame portion which is a female type, and llb is a groove for a crosspiece portion which is also a female type.

First, as shown in FIGS. 5(a) to (i) and FIG. Line up each groove 11
After laying the prepreg material B3 for the connecting portion corresponding to the connecting portion and a part of the crosspiece, and the prepreg material AI for the frame portion cut into appropriate dimensions, the above two steps are carried out. Do this alternately several times. At this time, as shown in FIG. Prepreg materials Bl and B2 shifted in opposite directions are used alternately, and when viewed as a whole, the portions of the prepreg material B for the connecting portion corresponding to the crosspieces become gradually shorter.

Next, as shown in FIG. 5 (D to (q)) and also in FIG. 6,
The prepreg materials Al and A2 for frame portions, the prepreg materials B1 to B5 for connecting portions, and the prepreg materials 01 to C6 for crosspiece portions are appropriately combined and laminated. At this time as well, the prepreg material Bl for the connecting portion has portions corresponding to the frame shifted in opposite directions.

B2 (see Fig. 5 (vertical) (P)) is used alternately, and prepreg materials C5 and C6 (
The stacking order (see FIGS. 5(j), (k), (n), and (o)) is alternately changed. In other words,
] - As described above, by sequentially laminating prepreg materials having partially different dimensions, it is possible to prevent the joints between the prepreg materials in different parts from concentrating in one place.

In addition, when laminating on the frame in the above process,
The edges of each prepreg material are folded up and laminated to form a flange portion, and the layers in the flange portion are formed to overlap in the axial direction of the grid structure.

Then, the above lamination process is repeated several times to complete the entire lamination process, and then the frame male mold 12 and the crosspiece male mold 13 (
(See Figures 2 and 3) and attach each port 12.
a. Press and shape the laminated prepreg material by tightening 13a (= 1 digit), then perform an initial heat curing treatment in this state.Furthermore, after the prepreg material has hardened,
Following the removal of each male die 12, 13, the ring 8 and jig 9 are removed, and the grid structure is extracted from the core 5 together with the cylindrical member 7, and then the cylindrical member 7 is disassembled to obtain the grid structure.

In the grid structure G thus formed, as shown in FIG. 7, the fiber direction in the frame portion 101 is
Since the layers of the flange portion 101a are formed in two directions, that is, the circumferential direction of the frame portion 101 and the direction orthogonal to the circumferential direction of the frame portion 101, and are formed integrally with each other in the approximately axial direction of the grid structure G, Sufficient strength can be obtained not only for loads in the compression direction but also for loads in the tensile force direction. In addition, since the grid structure G is integrally molded only from prepreg material, connection parts with other structures, such as port access holes 106, can be provided with high precision at arbitrary positions. In some cases, a boss member 107 made of a homogeneous material may be provided inside the flange portion 101a depending on the portability.

In the above embodiment, the case where a cylindrical triangular grid structure was manufactured was explained as an example, but the shape of the grid structure is not limited, and for example, as shown in FIG. 8(a) (
Rectangular cylindrical triangular grid structure 108 as shown in b)
It can be made into various shapes, such as a rectangular grid structure 109 as shown in FIG. 9, and necessary parts depending on the application can be molded integrally with the main body. moreover,
The type of prepreg material corresponding to each part of the structure is not limited to the above embodiments.

[Effects of the Invention] As described above, according to the method for manufacturing a grid structure of the present invention, when manufacturing a grid structure made of fiber reinforced plastic, the grid structure has a fixed fiber direction and After laminating various prepreg materials corresponding to each part of the body, such as the frame portion, the crosspiece, and the connecting portion between the frame and the crosspiece, in one mold, the prepreg materials are pressed and shaped using the other mold, Next, the prepreg material was hardened to form a grid structure, so based on the filament winding method (compared to conventional manufacturing methods, the fiber direction can be set freely, so the expected load can be reduced). It is possible to obtain a grid structure with sufficient strength in the direction of play.

[Brief explanation of drawings]

Fig. 1 is a professional diagram explaining the invention in detail, Fig. 2
The figure is a perspective view illustrating a device used in an embodiment of the present invention, FIG. 3 is a sectional view of the device shown in FIG. 2, and FIGS.
(h) is a plan view explaining the main types of prepreg materials used, FIGS. 5(a) to (q) are plan views each explaining an example of the lamination process, and FIG. 6 is shown in FIG. 7th perspective view showing an exploded view of the stacked state near the frame during the stacking process;
The figure is a cross-sectional view illustrating the molded grid structure.
Figures (a) and (b) are a front view and a plan view illustrating another example of the shape of the grid structure, FIG. 9 is a front view illustrating another example of the shape of the grid structure, and FIG. 10 is a cylindrical shape. Fig. 11 is a partial plan view of the core illustrating the state of the filament during the manufacturing process by the filament winding method, and Fig. 12 is a perspective view illustrating the triangular grid structure formed by the filament winding method. It is a sectional view explaining a frame part. G, 108, 109...grid structure, AI. A2...Prepreg material for the frame, B1-B5...Prepreg material for the connecting part, C1-C6...Prepreg material for the crosspiece, lla...Groove for the frame (one type), llb.・・・
Groove for the crosspiece (one mold), 12...Male mold for the frame (the other mold), 13...Male mold for the crosspiece (the other mold), 101...
-Frame part, 102... Crosspiece part. Patent Applicant Nissan Motor Co., Ltd. Patent Attorney Yutaka Oshio U) = C)

Claims (1)

[Claims] (1) When manufacturing a grid structure made of fiber-reinforced plastic, the fibers have a certain direction and correspond to each part of the grid structure, such as the frame, the crosspiece, and the connection between the frame and the crosspiece. A grid structure characterized by laminating various prepreg materials in one mold, pressing and shaping the prepreg materials in another mold, and then subjecting the prepreg materials to a curing treatment to form a grid structure. manufacturing method.