JP2003311765A - Production method for fiber reinforced plastic parts - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method for fiber reinforced plastic parts for integrally molding blow molded parts having a minute shape. <P>SOLUTION: In the production method for the hollow fiber reinforced plastic parts by laminating a prepreg having carbon fibers in a mold 10 to mold and cure the same in a heating furnace 1, the prepreg 11 is laminated on the inner surface of the mold and, after a material having the same kind as the prepreg is further laminated on the prepreg 11, a bag 12 is provided along the surface of the prepreg 11 laminated in the mold 10 and filled with air to perform blow molding. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fiber reinforced plastic part for molding the shape of an air spoiler (the rear stabilizer blade of an automobile) for achieving stability during high speed running of the automobile, and more particularly to a method for producing a fiber reinforced plastic component by internal pressure molding. The present invention relates to a method for manufacturing a fiber-reinforced plastic part to be molded.

[0002]

2. Description of the Related Art Conventionally, in the case of molding carbon fiber reinforced plastic (hereinafter also referred to as CFRP) and the like, in many cases, autoclave method, RTM method and hand lay-up molding are carried out to obtain a hollow body. For this purpose, a bonding process is used. Further, in order to integrally form the hollow body, a core is used as seen in injection molding of thermoplastic resin.

In recent years, it has been found that an internal pressure molding method having an adhesiveless structure can be applied to a cylindrical shape such as a tail cone member of a small helicopter, which has a large area opening. As a member having almost no opening, a steering wheel or the like having a relatively simple cross-sectional structure is manufactured by the same manufacturing method.

Further, with respect to an automobile air spoiler and its manufacturing method, a technique as disclosed in Japanese Patent Laid-Open No. 5-213235 is known. This technology consists of molding the upper and lower parts with a thermoplastic resin, fixing the molding to the seam of the upper and lower parts, and then bonding the adhesive ribs to the upper and lower parts to combine them. It is designed to form an air spoiler.

As a technique for molding a lighter weight air spoiler that withstands wind pressure during high-speed traveling, sheet-shaped thermosetting resin containing glass fibers is used to form upper and lower parts by hot pressing. A technique is also known in which molding is performed and the upper and lower parts are bonded and united by some means.

[0006]

However, as compared with the conventional technique, a technique for integrally molding a desired shape into a hollow shape is desired, and it is possible to perform molding using another resin or the like after the molding. . However, there is a concern that the bonding strength may be insufficient at the interface between different materials in the shaped part, the impact strength may be reduced, and there is a possibility that the external force including the temperature change may be affected.

Further, in the method of using the core as seen in the injection molding of thermoplastic resin, it is necessary to solve various factors such as positioning, splitting of the core, material (molten core: low melting point metal) and the like. there were.

Further, the application of the internal pressure molding method is limited to those having a relatively simple cross-sectional shape, and there is a problem that it is not applied to products having a fine shape.

In addition, the method of molding the upper and lower parts and adhering them by integration requires a large number of steps, resulting in a high manufacturing cost, and a part such as an air spoiler which requires an aesthetic appearance. There was a problem that the lower part was set in a jig to improve the accuracy of the mating surface, and it took time to finish the mating surface.

When the mating surfaces are bonded by heat treatment, it is necessary to consider to prevent thermal deformation, and when the mating surfaces of the upper and lower parts containing glass fibers are bonded. However, there is a problem that it is difficult to manufacture because the dust generated when the mating surfaces are processed contains glass fibers.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for producing a fiber-reinforced plastic part for integrally molding a hollow molded part having a fine shape.

[0012]

The invention described in claim 1 of the present invention, which has solved the above-mentioned problems, is a hollow hollow structure in which an uncured plastic layer having carbon fibers is laminated on a molding die to be formed and cured. In the method for manufacturing a fiber-reinforced plastic component, a step of laminating the uncured plastic layer on the inner surface of the molding die, a step of further laminating the same kind of material at a predetermined position of the laminated uncured plastic layer, and the molding die. A method for producing a fiber-reinforced plastic part, comprising: a step of providing a bag along the surface of the uncured plastic layer therein; and a step of filling the bag with air to perform hollow molding.

According to the first aspect of the present invention, the bag blown with high-pressure air swells in the molding die, whereby a more preferable molding shape can be obtained. In addition, since the accuracy of the shape of the hollow component is increased, the designer's design can be reproduced more faithfully. Further, by improving the accuracy of the shape and smoothly connecting the edge portions, the strength / rigidity of the parts is improved, and it is not necessary to design the bag near the net, so that the cost increase can be prevented. In addition, carbon fiber (hereinafter, C
(Also referred to as F), the designability can be improved. The uncured plastic layer corresponds to prepreg and the like.

According to a second aspect of the present invention, in the first aspect of the invention, the predetermined portion is a convex portion of the hollow fiber-reinforced plastic component when viewed from the inside.

The convex portion when viewed from the inside is, for example, a portion as shown in FIG. 3 described later (the tip portion comes inside the molding die).

According to the invention of claim 2, claim 1
In addition to the effect of the invention described in (1), the uncured plastic is further laminated in the vicinity of the corner to form the thickened portion, which relieves the tension on the bag and improves the followability of the bag to obtain the desired part shape. It can be molded and the aesthetic appearance and design strength can be secured. Further, the pressing force transmitted from the bag can be uniformly applied to the uncured plastic, and the strength can be improved.

The concave portion when viewed from the inside is, for example, a portion as shown in FIG. 4 which will be described later (the tip portion comes outside the molding die).

According to a third aspect of the present invention, in the first aspect of the invention, the predetermined portion is a concave portion of the hollow fiber-reinforced plastic component when viewed from the inside.

According to the invention of claim 3, claim 1
In addition to the effect of the invention described in (1), the thickened portion is formed by further laminating uncured plastic in the vicinity of the corner portion to reduce the tension on the bag and allow the bag to follow the shape. Therefore, while maintaining the desired appearance design, while preventing the bag from breaking during molding, the uncured plastic is heated and flows, so the pressing force transmitted from the bag is evenly applied to the uncured plastic, and the strength is increased. Can be improved.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION [Embodiment] An embodiment of a method for producing a fiber-reinforced plastic component according to the present invention will be described with reference to the drawings. FIG. 1 shows an outline of a method for manufacturing a fiber-reinforced plastic part according to the present invention.
FIG. 1A is a cross-sectional view showing a fiber-reinforced plastic part being heated in a furnace, and FIG. 1B is an enlarged view of part A in FIG. 1A. 1 (a) and 1 (b), an air spoiler 20 which is a hollow fiber-reinforced plastic component is a prepreg 11 formed by impregnating carbon fibers with an epoxy resin.
After being laminated on the inner surface of the molding die 10 for molding the air spoiler 20, a material of the same kind as the laminated prepreg 11 is further laminated to model the inner surface shape of the molding die 10, and the inner surface shape of the prepreg 11 is molded. A bag 12 is provided along the surface of the bag 12, and the bag 12 is filled with air and an internal pressure is applied from the inside, and the bag 12 is pressed against the molding die 10 to perform shape transfer and hollow molding. The air is pressurized air generated by the compressor 3 and is guided to the forming die 10 by the pipe 2. It is to be noted that, as described above, the present invention in which the same type of material is further laminated is applied to an acute angle portion (a pointed portion, a concave portion when viewed from the inside) as shown in FIG.

Here, the prepreg will be described. A prepreg is an intermediate molding material, which is a sheet formed by knitting fibers and impregnated with a resin to be in a semi-cured state, and is not completely cured.

At the time of molding, the prepreg is placed on the surface of the molding die 10, and then the bag 12 is inflated by applying an internal pressure, and pressed against the molding die 10. In that state, heat to mold and cure with epoxy resin.

As described above, in the case of molding using the molding method in which the internal pressure is applied by air, it is the followability of the bag 12 inserted into the molding die 10 that determines whether or not the molding is possible. By the way, the hollow integral molding of the air spoiler 20 makes it possible not only to eliminate the seams but also to improve the design of the design. Also, air spoiler 2
No. 0 requires a desired shape in order to obtain aerodynamic characteristics, so that a fine shape molding technique is important.

At this time, it is preferable from the viewpoint of molding that the bag 12 is formed in a near-net shape that is molded with high precision in advance. However, if the molding is performed with high precision in advance, the cost for parts will be greatly increased. Further, even in the case of the near net shape, if the displacement of the bag 12 occurs, the molding will be hindered. Therefore, by using the bag 12 having a relatively simple bag shape, the positioning problem is solved, but a new followability problem occurs.

For this reason, it is necessary to fill the material of the bag 12 with fluid material up to the portion where the pressure is applied. Here, a laminated body such as epoxy resin or prepreg 11 which is an intermediate molded member is used. Since these epoxy resin and prepreg 11 are fluidized by heating, pressure loss is small in a flowing material, and pressure is more easily transmitted than a rigid material such as a core. This point will be described later with reference to FIG.

Further, when the bag 12 having a simple shape is used, the problem of misalignment disappears, and it becomes unnecessary to consider the positioning. In molding, heating furnace 1 with bag 12 attached
Heat with. The temperature in the heating furnace 1 is maintained at a temperature of 120 to 130 ° C, but the bag 12 has a heat resistant temperature of 200 ° C.
As it is composed of a large amount of nylon, it does not change in quality when the epoxy resin is baked and hardened.

FIG. 2 shows an outline of an air spoiler made of a fiber reinforced plastic part according to the present invention, (a) is a perspective view showing the outline of the entire air spoiler, and (b) is a BB line in (a). FIG. The air spoiler 20 for an automobile shown in FIG. 2A has a hollow portion 21 as shown in FIG. 2B. And this hollow portion 21
Has an opening (not shown) communicating with the outside, and a high mount lamp (not shown) is embedded in the opening, and a hole for passing a wire connected to the high mount lamp is provided.

FIG. 3 is a diagram for explaining the followability of the pressurized bag according to the present invention. FIG. 3 (a) shows that the pressurized bag 12 is broken near the corner 31 of the mold 10. (B) is a cross-sectional view showing that the pressurized bag 12 is
FIG. 3 is a cross-sectional view showing a state where no breakage occurs in the vicinity of a corner 31 of the molding die 10. As shown in FIG. 3A, regarding the shape of the molding die 10 and the followability of the bag 12, the convex portion viewed from the inner surface of the air spoiler 20 is the bag 12 on the inner surface of the molding die 10.
, And the bag 12 is convex toward the inside of the bag 12. Therefore, in view of the followability of the bag 12, the bag 12 has a relatively advantageous shape, but when the forming die 10 has a corner portion 31, it may not be able to follow the shape, and the bag 12 is near the corner portion 31 of the forming die 10. It may stretch locally and become thin and break. Alternatively, the prepreg 11 may locally have a thin wall thickness.

Therefore, as shown in FIG. 3B, the prepreg 11 is further laminated in the vicinity of the corner 31 to increase the thickness 32.
Is formed to relieve the tension on the bag 12. In this way, the tension of the bag 12 is relieved and the thickened portion 32 of the prepreg 11 is heated and flows, so that the pressing force transmitted from the bag 12 can be uniformly applied to the prepreg 11.

FIG. 4 is a diagram for explaining the followability of the pressurized bag according to the present invention. FIG. 4 (a) shows that the pressurized bag 12 is broken near the corner 41 of the molding die 10. (B) is a cross-sectional view showing that the pressurized bag 12 is
FIG. 3 is a cross-sectional view showing a state of not breaking in the vicinity of a corner portion 41 of the molding die 10. As shown in FIG. 4A, the air spoiler 20
The concave portion viewed from the inner surface of the bag acts as a sharp concave shape on the bag 12 on the inner surface of the molding die 10,
Has an acute convex shape toward the outside of the bag 12.
Therefore, in view of the followability of the bag 12, the bag 12 cannot follow, and the bag 12 may exceed the extension limit of the bag 12 in the vicinity of the corner 41 of the mold 10 and may be damaged.

As described above, the bag 12 is inflated by applying the internal pressure to the bag 12 by the pressurized air to transfer the shape. However, it is difficult to transfer the shape of a right angle or an acute angle, and if the pressure is applied too much, the bag 12 may break or blow through.
Further, even if the bag 12 withstands the pressure, the bulge of the bag 12 does not expand to the back of the edge, and the bag 12 may be in a bridge state, and the shape cannot be transferred. Therefore, the cost is increased when the shape of the bag 12 is finished into a near net shape that matches the shape of the molding die 10.

Therefore, as shown in FIG. 4B, the prepreg 11 is further laminated in the vicinity of the corner portion 41 to increase the thickness increase portion 42.
Is formed to relieve the tension on the bag 12. In this way, the tension of the bag 12 is relaxed and the thickened portion 42 of the prepreg 11 is heated and flows, so that the pressing force transmitted from the bag 12 is evenly applied to the prepreg 11. Therefore, the bag 12 has a shape that can be followed, and while maintaining a desired external appearance design, prevents the bag 12 from breaking during molding, and because the prepreg 11 is heated and flows, a uniform pressure is applied to the inner surface of the molding die 10. Is imparted, and the reduction in strength can be avoided.

Next, a method is conceivable in which a core is set on the inner surface side of the molding die 10 or the shape itself is changed to follow the shape as a large R.

FIG. 5 shows a state in which the core is set in the molding die, (a) is a sectional view showing a state where the core is used for pressurization, and (b) is a core in (a). It is explanatory drawing which shows a mode that the pressing force is propagated by. This figure is
That is, the conventional example will be described.

As shown in FIG. 5A, it is difficult to position the core 51, and even if the inside of the bag 12 is filled with air,
Since the core 51 is a rigid member, a low pressure is transmitted to the prepreg 11. As shown in FIG. 5B, when the substantially core 51 of the triangle is used, the pressure transmitted to the prepreg 11 passes through the side S1 of the triangle and the side S2 because the core 51 is solid.
The pressure distributed to the side S3 and transmitted to the prepreg 11 becomes low. In this way, the pressure applied to the bag 12 is the core 5
Therefore, there is a problem in that the strength of the molded product is reduced because the prepreg 11 is not pressed with a desired pressure since it is applied to the molding surface after passing through 1.
Therefore, the shape transfer is weak and the positioning is not easy. In this way, the method using the core is possible to some extent, but is not sufficient. Further, as shown in FIG. 5A, it is difficult to collect the core 51 even if the core 51 is used and hollow molding is performed. Therefore, it is difficult to reduce the weight of the air spoiler 20.

FIG. 6 shows a state in which the design of the molding die has been changed, (a) is a cross-sectional view before the design is changed,
(B) is a cross-sectional view after the design is changed. This figure is also a diagram for explaining a conventional example, so to speak. As shown in FIG. 6 (b), when the design is changed so as to obtain the desired molding, the molding die 60 often cannot be applied because it is against the intention of the designer from the viewpoint of the appearance and merchandise. Further, from the viewpoint of performance for reducing the air resistance of the air spoiler, it is often impossible to change the shape. In other words, it is not possible to impose restrictions on the shape itself, because this leads to a decrease in the commercial viability of design.

In the present invention, as shown in FIGS. 3 (b) and 4 (b), after the prepreg 11 is once laminated on the inner surface of the molding die 10, the same kind of material as the laminated material is laminated to form the inner surface. By shaping the shape, the bag 12 can follow the shape, and while maintaining the desired external appearance design, the bag 12 is prevented from breaking at the time of molding, and the prepreg 11 is heated and flows. A uniform pressure is applied to the inner surface, and strength reduction can be avoided. Moreover, since it has fluidity, a pressure close to the internal pressure of the bag 12 is applied to any portion, and an intended shape can be obtained.

The above-described embodiment is an example for explaining the present invention, and the present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the invention. Is. For example, in the present embodiment, the pressure applied to the bag is pressurized air, but what is called a pressure that does not swell and damage the bag may be used. In addition to the pressurized air, a high pressure liquid may be used. Further, the example in which the prepreg is laminated on the thickened portion has been described, but resin or the like may be filled.

[0039]

As described above, according to the first aspect of the present invention, after the prepreg is laminated on the inner surface of the molding die, the same kind of material as the laminated prepreg is further laminated to form the inner surface of the molding die. Since it includes a bag provided along the surface of the prepreg laminated in the molding die having a part for shaping the shape of, the bag blown with high pressure air is more suitable by swelling in the molding die. A molded shape can be obtained. In addition, since the accuracy of the shape of the hollow component is increased, the designer's design can be reproduced more faithfully. In addition, due to the improved shape accuracy, the edges are connected smoothly, the strength and rigidity of the parts are improved, and it is not necessary to design the bag near the net, so that the cost increase can be prevented.

According to the second aspect of the invention, the prepreg is further laminated in the vicinity of the corner portion to form the thickened portion and the tension to the bag can be relieved, so that the followability of the bag is improved. In addition, it can be molded into a desired part shape, and an aesthetic appearance and design strength can be secured. Further, the pressing force transmitted from the bag can be uniformly applied to the prepreg.

According to the third aspect of the invention, the tension of the bag is relieved, and the bag has a shape that allows the bag to follow the shape of the prepreg. Since the prepreg is heated and flows, the pressing force transmitted from the bag is uniformly applied to the prepreg, and a decrease in strength can be avoided.

Further, it is possible to easily form a complicated shape in accordance with the requirements of the designer, and it is possible to improve the external appearance of the component.

As described above, according to the method for producing a resin molded product of the present invention, since a semi-cured fiber-reinforced plastic member is heat-treated to produce an integrally molded product, an adhesive agent, bolts, rivets, etc. are not required. The obtained molded product has high reliability in terms of mechanical strength.

[Brief description of drawings]

FIG. 1 schematically shows a method for producing a fiber-reinforced plastic part according to an embodiment of the present invention, (a) is a cross-sectional view showing the fiber-reinforced plastic part being heated in a furnace, and (b) is (a). 3 is an enlarged view of part A in FIG.

FIG. 2 is a schematic perspective view of an air spoiler made of a fiber-reinforced plastic component according to an embodiment of the present invention, and FIG. 2 (a) is a perspective view showing an overall outline of the air spoiler. (B)
FIG. 7B is a sectional view taken along line BB in (a).

FIG. 3 is a diagram for explaining the followability of the pressurized bag according to the embodiment of the present invention, in which (a) the pressurized bag is broken near the corners of the molding die. FIG. 6B is a cross-sectional view showing a state in which the pressurized bag does not break near the corners of the mold.

FIG. 4 is a diagram for explaining the followability of the pressurized bag according to the embodiment of the present invention, in which (a) the pressurized bag is broken near the corners of the mold. FIG. 6B is a cross-sectional view showing a state in which the pressurized bag does not break near the corners of the mold.

FIG. 5 is a cross-sectional view showing a state where a core is set in a molding die for explaining the embodiment of the present invention, and FIG. 5A is a sectional view showing a state where pressure is applied using the core; b) is (a)
FIG. 7 is an explanatory view showing a state in which a pressing force is propagated by the core in FIG.

6A and 6B show a state in which a design of a molding die is changed to explain an embodiment of the present invention, FIG. 6A is a sectional view before the design is changed, and FIG. 6B is a cross-sectional view after the design is changed. FIG.

[Explanation of symbols]

1 heating furnace 2 Pressurized air piping 3 compressor 10 Mold 11 prepreg 12 bags 20 air spoiler 21 hollow 31, 41 corners 32, 42 thickening part 51 core 60 Mold

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tatsuo Chiura             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory F-term (reference) 4F204 AA39 AD16 AG07 AG21 AG25                       AH18 FA01 FA13 FB01 FB11                       FB25 FF23 FF50 FN04 FN11                       FQ37

Claims (3)

[Claims] 1. A method for producing a hollow fiber-reinforced plastic part, which comprises forming an uncured plastic layer having carbon fibers on a molding die and curing the uncured plastic layer, wherein the uncured plastic layer is laminated on the inner surface of the molding die. A step of further laminating the same kind of material at a predetermined position of the laminated uncured plastic layer, a step of providing a bag along the surface of the uncured plastic layer in the mold, and supplying air to the bag. A method for producing a fiber-reinforced plastic part, comprising the steps of filling and hollow molding. 2. The method for producing a fiber-reinforced plastic component according to claim 1, wherein the predetermined portion is a convex portion of the hollow fiber-reinforced plastic component when viewed from the inside. 3. The method for producing a fiber-reinforced plastic component according to claim 1, wherein the predetermined portion is a concave portion of the hollow fiber-reinforced plastic component when viewed from the inside.