Method for forming composite hollow parts

Abstract

To provide a method for molding a composite hollow part which is capable of molding a high-quality composite hollow part, and a system for molding a hollow part.SOLUTION: A method for molding a composite hollow part according to the present disclosure, includes the steps for: covering a core with a first bag film; molding a hollow-shaped intermediate by overlaying composite fibers on the first bag film; placing the intermediate in an outer mold together with the core and the first bag film; covering the outer mold with a second bag film; heating the intermediate after making an air pressure outside the first bag film and inside the second bag film to be lower than the air pressure outside the second bag film and inside the first bag film; and demolding the composite hollow part molded by heating the intermediate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method and system for molding a composite hollow part. [Background technology]

[0002] Patent Document 1 discloses a method for producing a hollow resin molded product using a composite metal core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-193175 Summary of the Invention [Problem to be solved by the invention]

[0004] The method for producing a hollow resin molded product disclosed in Patent Document 1 has a problem in that it is not possible to produce a high-quality hollow resin molded product because unevenness is formed on the outer surface of the hollow resin molded product.

[0005] The present disclosure has been made in consideration of the above, and aims to provide a method for molding a composite hollow part and a hollow part molding system that are capable of molding a high-quality composite hollow part. [Means for solving the problem]

[0006] The molding method for a composite hollow part according to the present disclosure includes covering a core with a first bag film, forming a hollow intermediate by overlapping composite fibers on the first bag film, placing the intermediate together with the core and the first bag film in an outer mold, covering the outer mold with a second bag film, setting the air pressure outside the first bag film and inside the second bag film lower than the air pressure outside the second bag film and inside the first bag film, heating the intermediate, and demolding the composite hollow part molded by heating the intermediate. This molding method for a composite hollow part can mold a high-quality composite hollow part with a uniform thickness and no unintended unevenness on the surface.

[0007] In heating the intermediate body, the intermediate body may be heated in a state in which the core is attached to the intermediate body.

[0008] Demolding the composite hollow part may include reducing the air pressure inside the first bag film to be lower than the air pressure outside the first bag film, and then pulling out the core and the first bag film from the composite hollow part.

[0009] The outer mold may be covered with the second bagging film, the core may be removed from the intermediate body, and the air pressure outside the first bagging film and inside the second bagging film may be made lower than the air pressure outside the second bagging film and the air pressure inside the first bagging film, and then the intermediate body may be heated.

[0010] When removing the composite hollow part from the mold, the air pressure inside the first bag film may be made lower than the air pressure outside the first bag film, and then the first bag film may be pulled out from the composite hollow part.

[0011] In heating the intermediate body, the air pressure outside the first bag film and inside the second bag film may be reduced to a predetermined air pressure or lower, and then the intermediate body may be heated.

[0012] The core may be made of an elastically deformable material.

[0013] The hollow part molding system according to the present disclosure includes at least a core, a first bag film wrapped around the core, an outer mold on which an intermediate body formed by overlapping composite fibers on the first bag film is placed, a second bag film covering the outer mold, a pressure control device configured to be able to make the air pressure outside the first bag film and inside the second bag film lower than the air pressure outside the second bag film and the air pressure inside the first bag film, and a heating device for heating the intermediate body. This hollow part molding system is capable of molding a high-quality composite hollow part with a uniform thickness and without unintended unevenness on the surface.

[0014] The core may be made of an elastically deformable material. Effect of the Invention

[0015] The present disclosure makes it possible to provide a method for molding a composite hollow part and a hollow part molding system that are capable of molding a high-quality composite hollow part. [Brief description of the drawings]

[0016] [Figure 1] 3 is a flowchart showing a molding method for a composite hollow part according to the first embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view for explaining a molding method for the composite hollow part according to the first embodiment. [Diagram 3] FIG. 2 is a schematic cross-sectional view for explaining a molding method for the composite hollow part according to the first embodiment. [Figure 4] FIG. 1 is a diagram showing an example of a method for winding a ply. [Diagram 5]FIG. 2 is a schematic perspective view showing a molded composite hollow part and a state in which a core and a first bag film are pulled out from the molded composite hollow part. [Figure 6] 10 is a flowchart showing a molding method for a composite hollow part according to a second embodiment. [Figure 7] FIG. 11 is a schematic cross-sectional view for explaining a molding method for a composite hollow part according to a second embodiment. [Figure 8] FIG. 11 is a schematic cross-sectional view for explaining a molding method for a composite hollow part according to a second embodiment. [Figure 9] FIG. 2 is a schematic perspective view of an example of a molded composite hollow part and the pulling of a first bag film from the molded composite hollow part. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. In addition, the following description and drawings are appropriately simplified for clarity of explanation.

[0018] <Embodiment 1> Fig. 1 is a flow chart showing a method for molding a composite hollow part according to the first embodiment. Fig. 2 and Fig. 3 are schematic cross-sectional views for explaining the method for molding a composite hollow part. Fig. 2 and Fig. 3 show schematic cross-sectional views of each step of the flow chart shown in Fig. 1. In this embodiment, for example, a composite hollow part 202 is molded by a hollow part molding system 100. A specific description will be given below.

[0019] 2 and 3, the hollow part molding system 100 includes at least, for example, a core 101, a bag film (first bag film) 102, an outer mold 103, a bag film (second bag film) 104, a pressure control device 105, and a heating device 106. A composite hollow part 202 molded by the hollow part molding system 100 is installed, for example, inside a wind turbine blade or an airplane propeller for reinforcement.

[0020] First, the bag film 102 is wrapped around the core 101 (step S101).

[0021] The core 101 has a shape corresponding to the shape of the hollow part of the composite hollow part 202, which is a molded product. For example, the core 101 has a cylindrical shape. The core 101 is formed of a material having a durability sufficient to prevent plastic deformation during the molding process of the composite hollow part 202. However, the core 101 is preferably formed of an elastically deformable material such as silicon. This makes it possible to easily pull out the core 101 from the composite hollow part 202. Even if the core 101 has a partially curved shape, a shape with a partially different thickness, or a branched shape according to the shape of the hollow part of the composite hollow part 202, the core 101 can be pulled out from the composite hollow part 202 without being damaged. This makes it possible to reuse the core 101, thereby suppressing an increase in costs.

[0022] The bag film 102 is formed of a material that has airtightness to the extent that the pressure difference between the inside and outside of the bag film 102 can be maintained, and is also durable enough not to be damaged during the molding process of the composite hollow part 202. For example, the bag film 102 is formed of a material that has heat resistance to a heating temperature of 130 to 220 degrees or more when the composite hollow part 202 is molded from a material containing epoxy, and is formed of a material that has heat resistance to a heating temperature of 400 degrees or more when the composite hollow part 202 is molded from a material containing polyimide. In addition, for example, the bag film 102 is formed of a material that has durability to the extent that it is not damaged even when the pressure difference between the inside and outside of the bag film 102 is in the range of 0.3 to 10 atmospheres. Specifically, the bag film 102 is formed of a material such as nylon or silicone.

[0023] Furthermore, the bag film 102 is preferably made of a highly elastic material. This can prevent damage to the bag film 102 due to tension. Furthermore, the bag film 102 is preferably wound around the core 101 in such a way that it is intentionally wrinkled. This can prevent damage to the bag film 102 due to tension and improves deaeration properties.

[0024] Thereafter, the ply 200 is laid on the bag film 102 to form an intermediate body 201 which is in the process of forming a composite hollow part 202 (step S102).

[0025] The ply 200 is a sheet-like member containing composite fiber. By overlapping the plies 200, it is possible to form a high-strength composite hollow part 202. As shown in Fig. 4, by spirally winding the ply 200 on the bag film 102, it is possible to form a torsion-resistant composite hollow part 202.

[0026] Thereafter, the intermediate body 201 is placed in the outer mold 103 together with the core 101 and the bag film 102 (step S103). More specifically, the intermediate body 201 is sandwiched together with the core 101 and the bag film 102 between the upper mold 103a and the lower mold 103b that constitute the outer mold 103. This causes the outer surface of the intermediate body 201 to be molded into a shape corresponding to the shape of the outer mold 103. This also makes it possible to prevent unintended irregularities from being formed on the outer surface of the intermediate body 201.

[0027] Thereafter, the outer mold 103 is covered with the bag film 104 (step S104). The bag film 104 is made of the same material as the bag film 102.

[0028] Thereafter, the pressure control device 105 is used to make the air pressure outside the bag film 102 and inside the bag film 104 lower than the air pressure outside the bag film 104 and the air pressure inside the bag film 102, and then the heating device 106 is used to heat the intermediate body 201 (step S105).

[0029] By making the air pressure outside the bag film 102 and inside the bag film 104 lower than the air pressure outside the bag film 104 and the air pressure inside the bag film 102, pressure is applied from the inside to the outside of the bag film 102, so that the bag film 102 and the intermediate body 201 (ply 200) stick to the outer mold 103. As a result, the inner surface of the intermediate body 201 is formed into a desired shape. Note that the pressure control device 105 preferably lowers the air pressure outside the bag film 102 and inside the bag film 104 to a predetermined air pressure or less that is in a vacuum state or close to a vacuum state. As a result, the bag film 102 and the intermediate body 201 (ply 200) can stick to the outer mold 103 under a stronger pressure.

[0030] Also, for example, when the intermediate body 201 is formed from a material containing epoxy, the heating device 106 heats the intermediate body 201 to 130 to 220 degrees, and when the intermediate body 201 is formed from a material containing polyimide, the heating device 106 heats the intermediate body 201 to 400 degrees.

[0031] Thereafter, the intermediate body 201 is heated to remove the molded composite hollow part 202 (steps S106 and S107). Specifically, first, the bag film 104 and the outer mold 103 are removed from the composite hollow part 202 (step S106). Then, the core 101 and the bag film 102 are pulled out from the composite hollow part 202 (step S107). When pulling out the core 101 and the bag film 102 from the composite hollow part 202, it is preferable to use a pressure control device 105 or the like to make the air pressure inside the bag film 102 lower than the air pressure outside. This allows the bag film 102 to be attached to the core 101, making it easier to pull out the core 101 and the bag film 102 from the composite hollow part 202. The core 101 may be made of a material that shrinks when the air pressure inside the bag film 102 becomes lower than the air pressure outside. This makes it easier to pull out the core 101 and the bag film 102 from the composite hollow part 202.

[0032] As described above, the molding method for a composite hollow part according to this embodiment uses the core 101, outer mold 103, and bag films 102, 104 to perform the processes described above to mold a composite hollow part 202 in which composite fibers are overlapped. As a result, the molding method for a composite hollow part according to this embodiment can mold a high-quality composite hollow part that is free of unintended irregularities on the surface and has a uniform thickness. In other words, the molding method for a composite hollow part according to this embodiment can mold a high-strength, high-quality composite hollow part.

[0033] In the molding method for a composite hollow part according to the present embodiment, the core 101 may be made of an elastically deformable material such as silicon. This allows the core 101 to be easily pulled out of the composite hollow part 202. Even if the core 101 has a partially curved shape, a shape with partially different thicknesses, or a branched shape, depending on the shape of the hollow part of the composite hollow part 202 as shown in Fig. 5, for example, the core 101 can be pulled out of the composite hollow part 202 without being damaged. This allows the core 101 to be reused, thereby suppressing increases in costs.

[0034] <Embodiment 2> Fig. 6 is a flow chart showing a method for molding a composite hollow part according to the second embodiment. Figs. 7 and 8 are schematic cross-sectional views for explaining the method for molding a composite hollow part. Figs. 7 and 8 show schematic cross-sectional views of each step of the flow chart shown in Fig. 6. In this embodiment, for example, a composite hollow part 202 is molded by a hollow part molding system 100. A specific description will be given below.

[0035] First, the bag film 102 is wrapped around the core 101 (step S201).

[0036] Thereafter, the ply 200 is laminated on the bag film 102 to form an intermediate body 201 (step S202).

[0037] Thereafter, the intermediate body 201 is placed in the outer mold 103 together with the core 101 and the bag film 102 (step S203). More specifically, the intermediate body 201 is sandwiched together with the core 101 and the bag film 102 between the upper mold 103a and the lower mold 103b that constitute the outer mold 103. This causes the outer surface of the intermediate body 201 to be molded into a shape corresponding to the shape of the outer mold 103. This also makes it possible to prevent unintended irregularities from being formed on the outer surface of the intermediate body 201.

[0038] Thereafter, the outer mold 103 is covered with the bag film 104 (step S204).

[0039] Thereafter, the core 101 is pulled out from the intermediate body 201 before heating (step S205). This makes it possible to shorten the heating time of the intermediate body 201. The core 101 may be formed from a material that shrinks when the air pressure inside the bag film 102 becomes lower than the air pressure outside. This makes it easier to pull out the core 101 from the composite hollow part 202 by making the air pressure inside the bag film 102 lower than the air pressure outside.

[0040] Thereafter, the pressure control device 105 is used to make the air pressure outside the bag film 102 and inside the bag film 104 lower than the air pressure outside the bag film 104 and the air pressure inside the bag film 102, and the heating device 106 is used to heat the intermediate body 201 (step S206).

[0041] By making the air pressure outside the bag film 102 and inside the bag film 104 lower than the air pressure outside the bag film 104 and the air pressure inside the bag film 102, pressure is applied from the inside to the outside of the bag film 102, so that the bag film 102 sticks to the outer mold 103. As a result, the inner surface of the intermediate body 201 is formed into a desired shape. Note that the pressure control device 105 preferably lowers the air pressure outside the bag film 102 and inside the bag film 104 to a predetermined air pressure or lower that is in a vacuum state or close to a vacuum state. As a result, the bag film 102 can stick to the outer mold 103 under a stronger pressure.

[0042] Thereafter, the intermediate body 201 is heated to remove the molded composite hollow part 202 (steps S207 and S208). Specifically, first, the bag film 104 and the outer mold 103 are removed from the composite hollow part 202 (step S207). Then, the bag film 102 is pulled out from the composite hollow part 202 (step S208). When pulling out the bag film 102 from the composite hollow part 202, it is preferable to use a pressure control device 105 or the like to make the air pressure inside the bag film 102 lower than the air pressure outside. This allows the bag film 102 to shrink, making it easier to pull out the bag film 102 from the composite hollow part 202.

[0043] Other steps in the molding method for a composite hollow part according to embodiment 2 are similar to those in the molding method for a composite hollow part according to embodiment 1, and therefore will not be described further.

[0044] As described above, the molding method for a composite hollow part according to this embodiment uses the core 101, outer mold 103, and bag films 102, 104 to perform the processes described above to mold a composite hollow part 202 in which composite fibers are overlapped. As a result, the molding method for a composite hollow part according to this embodiment can mold a high-quality composite hollow part that is free of unintended irregularities on the surface and has a uniform thickness. In other words, the molding method for a composite hollow part according to this embodiment can mold a high-strength, high-quality composite hollow part.

[0045] In the molding method for a composite hollow part according to this embodiment, the core 101 may be made of an elastically deformable material such as silicon. This allows the core 101 to be easily pulled out of the composite hollow part 202. Even if the core 101 has a partially curved shape, a shape with partially different thicknesses, or a branched shape, depending on the shape of the hollow part of the composite hollow part 202 as shown in Fig. 9, for example, the core 101 can be pulled out of the composite hollow part 202 without being damaged. This allows the core 101 to be reused, thereby suppressing increases in costs.

[0046] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0047] 100 Hollow Parts Molding System 101 Core 102 Bag film (first bag film) 103 External mold 103a Upper mold 103b Lower mold 104 Bag film (second bag film) 105 Pressure control device 106 Heating device 200 ply (composite fiber) 201 Intermediate 202 Composite hollow parts

Claims

1. Cover the core with the first bag film, forming a hollow intermediate body by overlapping composite fibers on the first bag film; The intermediate body is placed in an outer mold together with the core and the first bag film, Cover the outer mold with a second bag film; The core is removed from the intermediate body. The intermediate body is heated after the air pressure outside the first bag film and inside the second bag film is lower than the air pressure outside the second bag film and the air pressure inside the first bag film; demolding the molded composite hollow part by heating the intermediate body; A method for forming hollow composite parts.

2. In the demolding of the composite hollow part, the air pressure inside the first bag film is made lower than the air pressure outside the first bag film, and then the first bag film is pulled out from the composite hollow part. A method for forming a composite hollow part according to claim 1.

3. In the heating of the intermediate body, the air pressure outside the first bag film and inside the second bag film is reduced to a predetermined air pressure or less, and then the intermediate body is heated. A method for molding a composite hollow part according to claim 1 or 2.

4. The core is formed of an elastically deformable material. A method for molding a composite hollow part according to claim 1 or 2.

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