JP4690613B2 - Method for producing composite hollow body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a composite material hollow body, and more particularly to a method for manufacturing a composite material hollow body using an eluting core.
[0002]
[Prior art]
In recent years, a fiber reinforced resin composite material in which a reinforcing fiber such as carbon fiber or glass fiber is impregnated with a thermosetting resin such as an epoxy resin or polyester as a base material has been developed and put into practical use. By using this fiber reinforced resin composite material, a lightweight and high-strength structure can be obtained, so various thin closed cross-sectional shapes such as air intake manifolds for vehicles, S-shaped tubes, U-shaped tubes, fuel tanks, etc. It is effectively used for the production of a structure having the following (hereinafter referred to as “hollow body”).
[0003]
When manufacturing the above-mentioned hollow body with a fiber reinforced resin composite material, there were the following problems. That is, if the hollow body has a simple shape such as a straight cylinder, it can be easily manufactured by the filament winding method or the like, but if the hollow body has a complicated closed cross-sectional shape, In addition, it is necessary to go through complicated procedures such as separately preparing the main body portion and the lid portion and bonding them, which takes time and effort.
[0004]
In order to solve the above problems, a core having a required shape is prepared from a low melting point alloy, and a fiber reinforced resin composite material using a thermosetting resin as a base material is laminated on the core, and the fiber reinforced resin composite material A method of manufacturing a hollow body made of a composite material by heating and curing the core, and then melting and removing the above-described core has been proposed (see JP-A-6-106632). ).
[0005]
[Problems to be solved by the invention]
However, according to the above-described method, after the fiber reinforced resin composite material is heated and cured, it is necessary to provide a step of heating and melting the core again, so that the manufacturing efficiency is lowered. In addition, when the core is heated and melted, it is necessary to heat at a temperature higher than the temperature at which the thermosetting resin that is the base material of the fiber reinforced resin composite material is cured, so that the fiber reinforced resin composite material deteriorates. However, the quality of the product may be reduced.
[0006]
An object of the present invention is to dramatically improve the production efficiency and prevent the deterioration of the fiber-reinforced resin composite material in the method for producing a hollow body made of a composite material, thereby significantly improving the quality of the product.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, a method for manufacturing a composite hollow body according to claim 1 is a method for manufacturing a core having a required shape using a low melting point alloy as shown in FIGS. A production step, a lamination step of laminating a fiber reinforced resin composite material having a thermosetting resin as a base material on the core, a semi-curing step of heating and primarily curing the laminated fiber reinforced resin composite material, A core elution step in which the core is melted and removed by passing through the semi-curing step and then the core is melted and removed, and a book in which the fiber reinforced resin composite material is cured by raising the temperature after passing through the core elution step. And a curing step.
[0008]
According to the first aspect of the present invention, the step of heating the fiber reinforced resin composite material using the thermosetting resin as a base material to perform primary curing, and the temperature rising and heating after this step are performed. Since the step of melting and removing the child and the step of heating and heating the fiber reinforced resin composite material after passing through this step, the fiber reinforced resin composite material is primarily cured and then cured. In addition, the core made of the low melting point alloy can be melted and removed. Therefore, it is not necessary to provide a step of heating and melting the core again after the fiber reinforced resin composite material is heated and cured. As a result, manufacturing efficiency can be significantly improved.
[0009]
In addition, according to the first aspect of the present invention, the step of heating the fiber reinforced resin composite material using the thermosetting resin as a base material for primary curing, and the temperature rising heating after this step is performed to make the low melting point alloy. A step of melting and removing the core and a step of heating and curing the fiber reinforced resin composite after passing through this step until the fiber reinforced resin composite is first cured and then cured In the meantime, the core made of the low melting point alloy can be melted and removed. Therefore, it is not necessary to heat at a temperature higher than the temperature at which the fiber reinforced resin composite material is cured. As a result, deterioration of the fiber reinforced resin composite material can be prevented, and the quality of the product can be significantly improved.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the manufacturing method of the composite-made hollow body which concerns on this invention is demonstrated in detail based on drawing.
[0011]
First, a cylindrical body 10 is prepared with a low melting point alloy (cylindrical body preparation step, see FIG. 1). The cylindrical body 10 is formed into a core 40 having a required shape through a rotating shaft attaching step and a cutting step, which will be described later. The core 40 manufactured from the cylindrical body 10 functions as a core jig for laminating the prepreg 50 of the fiber reinforced resin composite material on the outer surface in a laminating process described later and a core elution process described later. It is removed to the outside and functions to form a hollow portion inside the product.
[0012]
The melting point of the low melting point alloy used as the material of the cylindrical body 10 is set to be lower than the temperature at which the prepreg 50 is cured and formed. This is because the core 40 prepared from the cylindrical body 10 is melted and removed after the prepreg 50 is primarily cured in the semi-curing process and before being cured and molded in the main curing process. It is for forming a hollow part.
[0013]
Examples of the low melting point alloy used as the material of the cylindrical body 10 include an alloy in which Sn, Bi, Pb, In, Cd, Ag, Sb, Zn and the like are appropriately selected and mixed. In this embodiment, low-temperature solder 143 (manufactured by Senju Metal Co., Ltd., melting point 143 ° C.) is employed as the low melting point alloy.
[0014]
Next, the rotating shaft 20 made of steel is attached to the cylindrical body 10 (refer to FIG. 2). In the present embodiment, as shown in FIG. 2, the screw portion 21 of the rotary shaft 20 is screwed into the cylindrical body 10 from the center position of the surfaces (end faces) 11 positioned at both ends of the central axis of the cylindrical body 10. Thus, the rotating shaft 20 is fixed to the cylindrical body 10.
[0015]
Next, the surface of the cylindrical body 10 is cut with the cutting teeth 30 (see the cutting step, FIG. 3). In the present embodiment, the rotating shaft 20 attached to both ends of the cylindrical body 10 is supported by a jig (not shown), and the incisors 30 are rotated while the cylindrical body 10 is rotated around the rotating shaft 20. The surface of the cylindrical body 10 was cut to produce a bowl-shaped core 40 as shown in FIG. The core 40 having a required shape is manufactured by the above-described cylindrical body preparation process, rotating shaft mounting process, and cutting process (core manufacturing process).
[0016]
Next, a tape-shaped prepreg 50 in which a reinforcing fiber is impregnated with a thermosetting resin is laminated on the core 40 (lamination process, see FIG. 4). The prepreg 50 is primary-cured by heating in a semi-curing step described later, and is cured and molded by heating in the main curing step where the temperature is further increased.
[0017]
In the present invention, “primary curing” is a state where the prepreg 50 is not completely cured, but when the core 40 made of a low melting point alloy is melted and removed in the core elution step described later. It means a cured state to such an extent that the shape of the prepreg 50 does not collapse. Further, “cured” means a state in which the prepreg 50 is completely cured.
[0018]
Examples of the reinforcing fibers constituting the prepreg 50 include carbon fibers, glass fibers, aramid fibers, alumina fibers, polyethylene fibers, silicon carbide fibers, and boron fibers. The thermosetting resin used as the base material of the prepreg 50 is not particularly limited as long as it is primarily cured in the semi-curing process and further cured in the main curing process as described above. Examples thereof include unsaturated polyester resins, phenol resins, and bismaleide resins.
[0019]
Next, the rotating shaft 20 is removed from the laminated body 70 in which the prepreg 50 is laminated on the core 40, and the rotary shaft 20 is carried into a heating furnace or an autoclave 80 and heated to primarily cure the prepreg 50 (semi-curing step, see FIG. 5). When the laminated body 70 is disposed in the autoclave 80, the wire mesh 100 is disposed on the stainless steel container 90, and the laminated body 70 is disposed thereon (see FIG. 5). The container 90 and the wire mesh 100 are used in a core elution process described later. In the present embodiment, the temperature in the autoclave 80 is set to 60 ° C. in order to primarily cure the prepreg 50 having a primary curing temperature of 60 ° C.
[0020]
After this semi-curing step, the temperature inside the autoclave 80 was raised, the core 40 was heated and melted, and the rotary shaft 20 was removed, so that it was provided below the laminate 70 (not shown) ) The molten low melting point alloy 41 is removed from the through hole (core elution step, see FIG. 6). At this time, the low melting point alloy 41 melted by heating passes through the wire mesh 100 and accumulates in the container 90 (see FIG. 6).
[0021]
Due to the elution of the core 40 made of the low melting point alloy, a hollow portion 71 is formed inside the laminated body 70 (see FIG. 8). In the present embodiment, since the melting point of the core 40 made of the low melting point alloy is 143 ° C., the temperature in the autoclave 80 is set to about 150 ° C. to 160 ° C.
[0022]
In addition, since the prepreg 50 is primarily cured by the semi-curing process described above, the shape of the laminated body 70 is not collapsed when the core 40 is melted and removed in the core elution process.
[0023]
After this core elution step, the ambient temperature is further raised, and the prepreg 50 is heated and cured (main curing step, see FIG. 7). In the present embodiment, in the present embodiment, the temperature in the autoclave 80 is set to about 177 ° C. in order to cure the prepreg 50 having a curing temperature of 177 ° C. Then, the laminated body 70 is taken out from the autoclave 80, and the laminated body 70 (composite material hollow body) which has the hollow part 71 is obtained (refer FIG. 8).
[0024]
According to the method for manufacturing a hollow body made of a composite material according to the present embodiment, after the prepreg 50 is heated and primary-cured, the core 40 made of a low-melting alloy is melted by heating at a higher temperature, and the temperature is further increased. Since the prepreg 50 is cured by heating, the core 40 made of the low-melting-point alloy can be melted and removed between the time when the prepreg 50 is primarily cured and then cured. Therefore, there is no need to provide a step of heating and melting the core 40 again after the prepreg 50 is heated and cured. As a result, manufacturing efficiency can be significantly improved.
[0025]
In addition, according to the method for manufacturing a hollow body made of a composite material according to the present embodiment, after the prepreg 50 is heated and primary-cured, the core 40 made of a low-melting-point alloy is melted by heating and heating, Since the prepreg 50 is cured by heating at a high temperature, the core 40 made of the low melting point alloy can be melted and removed between the time when the prepreg 50 is primarily cured and then cured. Therefore, it is not necessary to heat at a temperature higher than the temperature at which the prepreg 50 is cured. As a result, deterioration of the prepreg 50 can be prevented, and the quality of the product can be significantly improved.
[0026]
In the present embodiment, the prepreg 50 having a primary curing temperature of 60 ° C. and a curing temperature of 177 ° C. is used, but is not limited to this. For example, the primary curing temperature is 120 ° C. and the curing temperature is 180 ° C. It is also possible to adopt a prepreg based on the epoxy resin. In this case, the core 40 prepared with the low-temperature solder 143 can be melted and discharged by first heating the prepreg at 120 ° C. and then maintaining the temperature at about 150 ° C. Further, the temperature can be raised and cured at 180 ° C.
[0027]
Moreover, in this Embodiment, although the process of melting the core 40 is provided, this process can also be abbreviate | omitted. That is, (as shown in the example of the prepreg using the above-described epoxy resin as a base material), after the prepreg is primarily cured, the temperature is raised to 180 ° C. and maintained at this temperature, whereby the core 40 is melted and discharged. The prepreg 50 can be cured and formed at the same time. In this case, the core 40 is melted and discharged in the main curing step.
[0028]
【The invention's effect】
According to the first aspect of the present invention, there is no need to provide a step of heating and melting the core again after the fiber reinforced resin composite is heated and cured. As a result, manufacturing efficiency can be significantly improved.
[0029]
Moreover, according to invention of Claim 1, it is not necessary to heat at the temperature higher than the temperature which hardens the thermosetting resin which comprises a fiber reinforced resin composite material. As a result, deterioration of the fiber reinforced resin composite material can be prevented, and the quality of the product can be significantly improved.
[Brief description of the drawings]
FIG. 1 is a perspective view for explaining a cylindrical body preparation step in a method for producing a composite hollow body according to an embodiment of the present invention.
FIG. 2 is a perspective view for explaining a rotating shaft attaching step in the method for producing a composite hollow body according to the embodiment of the present invention.
FIG. 3 is a perspective view for explaining a cutting step in the method for manufacturing a composite hollow body according to the embodiment of the present invention.
FIG. 4 is a perspective view for explaining a stacking step in the method for manufacturing a composite hollow body according to the embodiment of the present invention.
FIG. 5 is a front view for explaining a semi-curing step in the method for producing a composite hollow body according to the embodiment of the present invention.
FIG. 6 is a front view for explaining a core elution step in the method for manufacturing a composite hollow body according to the embodiment of the present invention.
FIG. 7 is a front view for explaining the main curing step in the method for manufacturing a composite hollow body according to the embodiment of the present invention.
FIG. 8 is a partially cutaway cross-sectional view showing a composite material hollow body manufactured by the method for manufacturing a composite material hollow body according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Cylindrical body 11 End surface 20 Rotating shaft 21 Thread part 30 Cutting tooth 40 Core 41 Molten low melting point alloy 50 Prepreg 60 Winding head 70 Laminate 71 Hollow part 80 Autoclave 90 Stainless steel container 100 Wire mesh

Claims (1)

A core manufacturing process for manufacturing a core of a required shape with a low melting point alloy;
A laminating step of laminating a fiber reinforced resin composite material based on a thermosetting resin on the core;
A semi-curing step of heating and primary curing the laminated fiber reinforced resin composite material;
A core elution step in which the core is melted and removed by heating and heating after the semi-curing step;
And a main curing step of curing the fiber-reinforced resin composite by heating and heating after the core elution step.

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