JPH0470372B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing fiber reinforced composite materials.

A type of so-called composite material, which is obtained by combining two or more types of materials or forming two or more phases by physical or chemical methods, contains a long fiber reinforcement material and a matrix material. There are fiber-reinforced composite materials manufactured by combining these materials.

When manufacturing fiber-reinforced composite materials, a method is often used in which reinforcing long fibers are preformed into a predetermined shape and the resulting molded body is impregnated with a molten matrix material. However, if the molded shape is complicated, it is difficult to preform the long fibers to match the shape, and there are disadvantages in that uneven fiber density occurs in the molded product, resulting in non-uniform material quality. Additionally, in order to compensate for this inconvenience, a method has been used in which a special jig is used to orient the long fibers according to a complex shape, and the matrix material is soaked in with the jig attached. , there was a problem that the jig had to be left behind in the finished product.

The present invention has been made in view of the above-mentioned points, and its purpose is to provide a manufacturing method that can easily manufacture fiber-reinforced composite materials having complex shapes.

The method for producing a fiber reinforced composite material according to the present invention includes:
Long fibers having a relationship between length and outer diameter d of /d>5000 are arranged in a direction that matches the mold, and
/d≦5000 short fibers are inserted to bridge the long fibers, and then pressurized to form a member shape in advance, and the resulting molded body is impregnated with the molten matrix material. It is characterized by

According to the present invention having such a configuration, the long fibers are oriented and arranged according to the mold, and the short fibers are inserted to bridge between the oriented long fibers, thereby causing entanglement of both fibers. , the short fibers act as a jig to maintain the orientation of the long fibers,
A uniform molded body can be obtained.

At this time, the relationship between the length of long fibers and short fibers and the outer diameter d is /d>5000 and /d≦5000, respectively.
Particularly remarkable effects can be obtained in the case of

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a process for producing a preformed body of a valve used in a four-stroke automobile engine using the method for producing a fiber-reinforced composite material according to the present invention will be described with reference to the drawings.

First, two-part primary molding molds 1 and 2, each molded into a symmetrical shape, are stacked on top of each other. Then,
Long fibers 3a such as metal fibers or inorganic fibers are arranged to match the mold, and short fibers 3b are arranged.
A predetermined amount of the fibers are inserted into the fiber storage portions 1a and 2a provided in the molds 1 and 2, respectively, in order to bridge between the long fibers 3a, while overlapping each other in a substantially spongy shape.

Here, long fibers refer to those whose outer diameter and length are /d>5000, whereas short fibers refer to those whose outer diameter and length are /d≦5000. Examples of the material of the short fibers 3b include silicon carbide (SiC) and boron (B).
Silicon carbide can be formed into either long fibers or short fibers depending on how it is produced, and short fibers can also be obtained by cutting the long fibers into predetermined dimensions. Further, boron already satisfies the above-mentioned dimensional conditions as a short fiber during its composition process, and is used as is. Another material for the short fibers 3b is polyacrylonitrile carbon fiber (PAN), which is formed into long fibers and then cut to be used as short fibers, similar to the silicon carbide described above.

When the insertion of the long fibers 3a and short fibers 3b into the fiber storage parts 1a and 2a is completed, next, two pressure plates 4 and 5 having a symmetrical shape are overlapped and inserted into the fiber storage parts 1a and 2a. A fiber group consisting of long fibers 3a and short fibers 3b is pressure-formed by the force applied to the pressure plate. The bottoms of the fiber storage sections 1a and 2a and the pressing ends of the pressing plates 4 and 5 are configured to form a cylindrical void as a whole, and the molded product obtained by pressure forming is It becomes cylindrical. In addition, when the long fibers 3a and short fibers 3b are mixed, molding becomes easier if a predetermined liquid is mixed with the short fibers 3b to make them semi-liquid. Furthermore, by mixing a suitable binder into the liquid, the molded product can be easily released from the mold and handled in the subsequent composite process.

The molded body 6 obtained as described above is placed in one of the two-part secondary molds 7 and 8. The secondary forming molds 7 and 8 have symmetrical shapes, and each of the secondary forming molds has storage portions 7a and 8a having an inner diameter corresponding to the axial diameter of the molded body 6, and a storage portion 7.
Large diameter portions 7c and 8c are formed which are continuous to a and 8a via taper portions 7b and 8b. As shown in FIG. 4a, the molded body 6 is placed in the storage section 7a.
(or 8a). The tapered portions 7b and 8a are for forming the bulb head portion. As shown in FIG. 4b, for example, the end of the molded body 6 stored in the storage section 7a on the tapered section 7b side is loosened into a flower shape in accordance with the tapered section.
Next, short fibers 3b are added to the loosened portion.

When the replenishment of the short fibers 3b to the loosened part is completed, the secondary forming molds 7 and 8 are overlapped, and as shown in FIG.
The pressurizing piston 9 is inserted into the large diameter portions 7c and 8c as shown in FIG. In addition, storage sections 7a and 8
The end of a is closed by a bottom mold 10. Due to the pressure applied by the pressure piston 9, the loosened portion of the molded body 6 is completely filled with short fibers 3b that are replenished later. While maintaining the pressurized state by the pressure piston 9, the molded body 6 is heated by a heating means (not shown) to harden the molded body. Thereafter, the hardened molded body 6 is taken out by releasing the secondary molds 7 and 8 and the bottom mold 10.

A valve preform is thus obtained.

As detailed above, in the method for producing a fiber-reinforced composite material according to the present invention, long fibers are oriented and arranged according to the mold, and short fibers are inserted and mixed to bridge between the long fibers. The molded article is formed by applying pressure. Therefore,
The entanglement effect with the short fibers makes it easy to orient the long fibers to match complex shapes, making it possible to manufacture fiber-reinforced composite materials with complex shapes. In addition, since the short fibers play the role of a jig for setting the orientation of the long fibers, there is no need to manufacture a special jig for setting the orientation of the long fibers, and the molded product made in this way If the jig is impregnated with the matrix material, the jig will not be left behind in the finished product.

In addition, in the method for producing a fiber-reinforced composite material according to the present invention, short fibers are replenished in areas where the fiber density of the long fibers is small, so that the fiber density becomes uniform as a whole, and the strength of the fiber-reinforced composite material is stabilized. be.

Furthermore, in the method for manufacturing a fiber reinforced composite material according to the present invention, the long fibers and short fibers are oriented in a state where they are entwined with each other, so even when manufacturing a product that has a particularly complex shape and is subject to a complex load, the strength and strength of the composite material can be improved. Sufficient rigidity can be obtained.

Furthermore, in the method for producing a fiber-reinforced composite material according to the present invention, appropriate voids are formed by the short fibers between the long fibers in the molded body, making it easier to impregnate the matrix agent into the molded body. There is.

[Brief explanation of drawings]

Figure 1, Figure 2, Figure 3, Figure 4 a, b and c
FIG. 3 is a diagram for explaining the process of manufacturing a preformed body of a valve for a four-cycle automobile engine using the method for manufacturing a fiber-reinforced composite material according to the present invention. Explanation of symbols of main parts, 1, 2... Primary mold, 3a... Long fiber, 3b... Short fiber, 4, 5...
... Pressure plate, 6 ... Molded body, 7, 8, ... Secondary mold, 9 ... Pressure piston, 10 ... Bottom mold.

Claims (1)

[Claims] 1. Long fibers with a relationship between length and outer diameter d of /d > 5000 were arranged to match the mold, and short fibers with /d≦5000 were inserted to bridge between the long fibers. A method for producing a fiber-reinforced composite material, characterized in that the material is then pressurized to form a member shape in advance, and the resulting molded product is impregnated with a molten matrix material.