JPH0441889B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) 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 grid consisting of a large number of crosspieces 102 between two ring-shaped frames 101, 101, and is suitable for the core structure of an artificial satellite or the like. It is used as a joint between the kick motor at the top of the rocket and the lower rocket motor, and the material used is particularly fiber reinforced plastic (CFRP) using carbon fiber.

Then, the above-mentioned grid structure G in the conventional
was manufactured based on the filament winding method. This is done by forming a groove corresponding to the shape of the grid structure G on the outer periphery of the cylindrical core using a removable jig, and in the groove of the rotating core,
A continuous carbon fiber filament impregnated with resin is wound under 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. Note that, 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 above, since continuous carbon fiber filaments are wound one after another,
As shown in the figure, a part of the core is a filament F wound from the crosspiece groove 103 to the frame groove 104.
A portion 105a where the fibers are sparse is created between the filament F wound from the frame groove 104 to the other crosspiece groove 103, and an intersection portion 105b of the filament F is generated on the other hand. There was a problem in that the content ratio was significantly different in some parts, which was not favorable in terms of strength, and there was also a problem in that partial reinforcement could not be performed. Furthermore, as shown in FIG. 12, the frame 101 of the grid structure is often formed with a flange 101a for attaching clamp bands, bolts, nuts, etc. used for connection with other structures. , the portion 105a where the fibers are in a sparse state as described above.
In addition to this, since the fiber directions of the filaments F in the frame portion 101 are all circumferential, there is a problem in that the strength against tensile load particularly in the vicinity of the flange portion 101a is reduced.

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

[Structure of the Invention] (Means for Solving the Problems) The method for manufacturing a grid structure according to the present invention will be explained based on FIG. 1. When manufacturing a fiber reinforced plastic grid structure, in step 1, After laminating various prepreg materials having a certain fiber direction and corresponding to each part of the grid structure, such as the frame part, the crosspiece part, and the connecting part between the frame part and the crosspiece part, in one mold, step 2 is carried out. In step 3, the prepreg material is pressed and shaped using the other mold, and then step 3
The method is characterized in that the prepreg material is subjected to a hardening treatment to form a grid structure. In addition, the above prepreg material is made by forming fiber bundles such as carbon fiber filaments into a cloth shape in a certain fiber direction, impregnating this with a thermosetting resin mixed with a hardening agent, a filler, etc., 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 the reference numeral 5 indicates 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. Further, in forming the female mold, two rings 8, 8 are fitted to the core 5 with a splittable cylindrical member 7 in between, and a large number of triangular shapes are formed on the surface of the cylindrical member 7. By fixing the jigs 9 with bolts 10,
A frame groove 11a corresponding to the frame of the grid structure is formed between the ring 8 and the jig 9, and a frame groove 11a corresponding to the frame of the grid structure is formed between each jig 9.
1b.

Further, each ring 8 is provided with a frame male mold 12 (partially shown in the figure) as the other mold that forms a flanged frame with the ring 8.
2a is detachably provided, and on the outer peripheral side of each jig 9, there is a male mold 1 for a crosspiece, which also serves as the other mold to form a crosspiece between the jig 9 and the cylindrical member 7.
3 (partially shown in the figure) is detachably provided. Note that the male die 13 for the crosspiece has a spacer 14 interposed between each jig 9 and the jig 9.
A bolt 13 is screwed into the cylindrical member 7 through the
It is designed to be installed with a, each male type 12, 1
3 is divided into several parts.

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

Prepreg material is made by impregnating a carbon fiber mat with a fixed fiber direction with a thermosetting resin and drying it. It can be roughly divided into prepreg material A for the frame, prepreg material A for the frame, and prepreg material A for the frame, near the joint between the frame and the crosspiece. It is divided into prepreg material B for connecting portions and prepreg material C for crosspiece portions.

The prepreg material A for the frame has a fiber direction along the circumferential direction of the frame, and as shown in FIG.
As shown in FIG. b, there is a prepreg material A2 corresponding to a part of the frame part and the connecting part, and it may be used by cutting it into appropriate dimensions.

The prepreg material B for the connecting portion has a fiber direction along the axial direction of the grid structure, and corresponds to the connecting portion, the frame portion, and a part of the crosspiece as shown in Fig. 4c and d. Prepreg materials B1 and B2, prepreg material B3 corresponding to the connecting part and a part of the crosspiece as shown in FIG. 4e, prepreg material B4 corresponding to a part of the connecting part, as shown in FIG. 4f There is a prepreg material B5 that corresponds to a part of the connecting part and the frame part. In addition, even if the prepreg material B for the connecting part is similar in form with the prepreg materials B1 and B2 corresponding to the connecting part, the crosspiece, and a part of the frame, for example, the parts corresponding to the frame are placed in opposite directions. There are several types of prepreg materials, including those with different lengths l (shown in Figure 4 d)) corresponding to the crosspieces.

The prepreg material C for the crosspiece has a belt shape with the fiber direction mainly along the longitudinal direction, and the 4th g,
As shown in h, there are various prepreg materials C1 to C4 cut into appropriate lengths. In addition, as shown in FIG. 4e and f, prepreg materials C5 and C6 for the crosspiece portion also correspond to a part of the connecting portion.
The ends of these prepreg materials C5 and C6 are bent so that the fiber direction at the connecting portion coincides with the axial direction. Note that the length of each of the prepreg materials C1 to C6 for the crosspieces can be set depending on the dimensions of the prepreg material B for the connecting portion, and as is clear from the illustration, the length of the prepreg materials C1 to C6 for the connecting portions may be set depending on the cutting dimensions. It can also be used as prepreg material B for parts.

FIGS. 5a-5q and 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 mold, and 11b is a groove for a crosspiece portion which is also a female mold.

First, as shown in FIG. 5 a to i and FIG. 6, first, connecting portion prepreg materials B1 corresponding to the connecting portion, the frame portion, and a part of the crosspiece are lined up in the circumferential direction, and each groove 11a is , 11b, the connecting part prepreg material B3 corresponding to the connecting part and a part of the crosspiece, and the frame part prepreg material A1 cut into appropriate dimensions are laminated, and the above two steps are carried out as follows. Do this alternately several times. At this time, as shown in Fig. 5 a, c, e, g, and i, the prepreg material B for the connecting part, which also corresponds to a part of the frame part, is shifted in opposite directions. Prepreg materials B1 and B2 are used alternately, and when viewed as a whole, the portion of the prepreg material B for the connecting portion corresponding to the crosspiece becomes gradually shorter.

Next, as shown in FIGS. 5j to q and also shown in FIG. 6, the prepreg materials A1 and A2 for the frame portions, the prepreg materials B1 to B5 for the connecting portions, and the prepreg materials C1 to C6 for the crosspiece portions are combined as appropriate. Perform lamination. At this time as well, prepreg materials B1 and B2 (see Fig. 5, l and p) for the connecting portions whose portions corresponding to the frame portions are shifted in opposite directions are used alternately, and The stacking order of the prepreg materials C5 and C6 (see FIG. 5 j, k, n, 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 prepreg materials in different parts from concentrating in one place.

In addition, when laminating the frame part in the above process, the edges of each prepreg material are folded up to form the flange part, and the layers in the flange part are stacked in the axial direction of the grid structure. It is formed so that it overlaps with the

Then, the above lamination process is repeated several times to complete the entire lamination process, and after this, the frame male mold 12 and the crosspiece male mold 13 (see FIGS. 2 and 3) are respectively attached to each bolt 12a. , 12a, the laminated prepreg material is press-shaped and then subjected to an initial heat curing treatment in this state. Furthermore, after the prepreg material has hardened, each male mold 1
Following the removal of 2 and 13, ring 8 and jig 9
After removing the grid structure and extracting the grid structure together with the cylindrical member 7 from the core 5, the cylindrical member 7 is disassembled to obtain the grid structure.

Grid structure G formed in this way
As shown in FIG. 7, in particular, the fiber direction in the frame portion 101 is in two directions, the circumferential direction of the frame portion 101 and the direction orthogonal to this, and the layer of the integrally molded flange portion 101a is Since they are formed so as to overlap substantially in the axial direction of the grid structure G, sufficient strength can be obtained not only for the load in the compression direction but also for the load in the tensile direction. In addition, since the grid structure G is integrally molded only from prepreg material, connection parts with other structures, such as bolt mounting holes 106, can be provided with high precision at arbitrary positions. ,
Flange portion 101a due to bolt installation
A boss member 107 made of a homogeneous material may be provided inside the.

In addition, in the above embodiment, the case where a cylindrical triangular grid structure was manufactured was explained as an example.
The shape of the grid structure is not limited;
For example, it can be made into various shapes such as a rectangular cylindrical triangular grid structure 108 as shown in FIGS. 8a and b, or a rectangular grid structure 109 as shown in FIG. Necessary parts can be molded integrally with the main body. Furthermore, the type of prepreg material corresponding to each part of the structure is not limited to the above embodiments.

[Effects of the Invention] As explained above, according to the method for manufacturing a grid structure of the present invention, when manufacturing a grid structure made of fiber-reinforced plastic, it is possible to After laminating various prepreg materials corresponding to respective parts such as the frame, 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, and then the Because the prepreg material is hardened to form a grid structure, the fiber direction can be set freely compared to the conventional manufacturing method based on filament winding, so it is possible to set the fiber direction freely in the direction of the expected load. In contrast, it is possible to obtain a grid structure with sufficient strength, prevent local fibers from becoming denser, and have the remarkable effect of being able to freely perform partial reinforcement.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating the configuration of the present invention, FIG. 2 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 FIG. 4 a to h are plan views illustrating the main types of prepreg materials used, FIGS. 5 a to q are plan views illustrating an example of the lamination process, and FIG. FIG. 7 is a cross-sectional view illustrating a molded grid structure, and FIGS. 8 a and b are front views illustrating other examples of shapes of the grid structure. and a plan view, FIG. 9 is a front view illustrating another example of the grid structure, FIG. 10 is a perspective view illustrating a cylindrical triangular grid structure, and FIG. 11 is manufactured by filament winding method. FIG. 12 is a partial plan view of the core illustrating the state of the filament during the process, and a sectional view illustrating the frame of the grid structure formed by the filament winding method. G, 108, 109...grid structure, A
1, A2...Frame prepreg material, B1 to B5...
...Prepreg material for the connecting part, C1-C6...Prepreg material for the crosspiece, 11a...Groove for the frame (one mold),
11b...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, 102... Pier.

Claims (1)

[Claims] 1. When manufacturing a grid structure made of fiber-reinforced plastic, various types of fibers having a fixed fiber direction and corresponding to each part of the grid structure, such as the frame, the crosspiece, and the connection between the frame and the crosspiece, are used. After laminating prepreg materials in one mold, pressing and shaping the prepreg materials in the other mold, and then subjecting the prepreg materials to a curing treatment to form a grid structure. Method.