Composite material molding jig and composite material, molding method

A composite material molding jig for molding a long member made of a fiber base material and a resin on a plate member includes: a first member that is made of a material having a thermal expansion coefficient equivalent to a thermal expansion coefficient of the long member, internally includes a space serving as a mold of the long member, and has an outer surface formed flat in a longitudinal direction; and a second member that is made of a material lighter than the material of the first member, internally includes a space shaped to contain the first member, and has an inner surface formed flat in the longitudinal direction, wherein the fiber base material is placed in the space inside the first member, and the first member is placed in the space inside the second member for molding the long member.

TECHNICAL FIELD

The present invention relates to a composite material molding jig and a composite material molding method for a resin composite material.

BACKGROUND ART

A molding method of molding a thermosetting resin composite material with use of a mold made of a material having a thermal expansion coefficient same as a thermal expansion coefficient of a molded article (PTL 1).

CITATION LIST

Patent Literature

the Publication of Japanese Patent No. 2947873

SUMMARY OF INVENTION

Technical Problem

Fiber Reinforced Plastics (FRP) and Carbon Fiber Reinforced Plastics (CFRP), which are resin composite materials, are lightweight and excellent in mechanical strength. Therefore, the resin composite materials are used for a structural member of an aircraft and the like. For example, to mold a skin of the aircraft or a reinforcing stringer, a cured or raw (uncured) skin41is placed on a lower mold40, a raw (uncured) stringer42made of a fiber base material is placed on the skin41, and an upper mold (mandrel43) is placed on the stringer42as illustrated inFIG.9. Further, after the raw skin41and the raw stringer42are impregnated with a resin, the resin is heated and cured to mold the structural member including the cured skin41and the cured stringer42.

As the mandrel43used for molding the resin composite material, a lightweight mandrel made of an aluminum alloy is used for manual handling. In particular, in a case where a large-sized (1 m or more) molded article is molded, deformation may occur due to thermal expansion of the mandrel43. Therefore, the mandrel43is divided in a longitudinal direction. For example, inFIG.9, the mandrel43is divided into a plurality of parts at dividing zones B. In a case where the mandrel43is divided in such a manner, a gap for accommodating thermal expansion is provided using a spacer, leading to prolonged installation of the mandrel43.

A structure of the mandrel43will be described with reference toFIG.10andFIG.11. The mandrel43has a substantially triangular prism shape, and has a substantially triangular cross-section. The stringer42has an inverted T-shaped cross-section. Therefore, the mandrel43that is a mold to form the stringer42internally includes an inverted T-shaped space S in a longitudinal direction. The mandrel43may be made up of one member; however, in a case where a thickness of the stringer42is changed during molding, it is necessary to divide the mandrel43not only in the above-described longitudinal direction but also in a width direction. For example, as illustrated inFIG.10andFIG.11, the mandrel43is made up of two blocks43aand43bthat are divided at a center in the width direction of the mandrel43. In this case, to prevent the two blocks43aand43bfrom falling down during molding, an angle member44having a substantially L-shaped cross section is disposed at a top part of the mandrel43(blocks43aand43b).

As described above, the mandrel43is divided not only in the longitudinal direction but also in the width direction in some cases. In such a case, installation of the mandrel43further takes a lot of time.

An object of the present invention, which has been made to solve the above-described problems, is to provide a composite material molding jig and a composite material molding method that are easy in installation and can contribute to reduction in a manufacturing cost.

Solution to Problem

According to a first invention to solve the above-described problems, a composite material molding jig for molding a long member made of a fiber base material and a resin on a plate member, includes: a first member that is made of a material having a thermal expansion coefficient equivalent to a thermal expansion coefficient of the long member, internally includes a space serving as a mold of the long member, and has an outer surface formed flat in a longitudinal direction; and a second member that is made of a material lighter than the material of the first member, internally includes a space shaped to contain the first member, and has an inner surface formed flat in the longitudinal direction. The fiber base material is placed in the space inside the first member, and the first member is placed in the space inside the second member for molding the long member.

According to a second invention to solve the above-described problems, in the composite material molding jig according to the above-described first invention, the first member has an outer shape similar to a shape of the internal space.

According to a third invention to solve the above-described problems, in the composite material molding jig according to the above-described first or second invention, the second member is provided over an entire length of the first member or is provided at a plurality of positions of a part of the entire length of the first member.

According to a fourth invention to solve the above-described problems, in the composite material molding jig according to any one of the above-described first to third inventions, a surface of the first member and a surface of the second member coming into contact with each other are coated with a mold release agent, are stuck with a mold release tape, or are subjected to mold release coating.

According to a fifth invention to solve the above-described problems, in the composite material molding jig according to any one of the above-described first to fourth inventions, the first member is divided into two parts at a center in a width direction of the first member, and the second member is divided into two parts at a center in a width direction of the second member.

According to a sixth invention to solve the above-described problems, in the composite material molding jig according to the above-described fifth invention, in a case where the first member is divided in a longitudinal direction of the first member, one of the two parts divided in the width direction of the first member and another part are divided at different positions in the longitudinal direction.

According to a seventh invention to solve the above-described problems, in the composite material molding jig according to the above-described fifth or sixth invention, the second member has a triangular prism shape as a whole including the first member, and an angle member that has an L-shaped cross-section and is fitted to a top part of the triangular prism shape is provided at the top part.

According to an eighth invention to solve the above-described problems, a composite material molding method for molding a long member made of a fiber base material and a resin on a plate member, includes: placing the fiber base material to be the long member, on the plate member; placing the fiber base material in a space inside a first member, the first member being made of a material having a thermal expansion coefficient equivalent to a thermal expansion coefficient of the long member, internally including the space serving as a mold of the long member, and having an outer surface formed flat in a longitudinal direction; placing the first member in a space inside a second member, the second member being made of a material lighter than the material of the first member, internally including the space shaped to contain the first member, and having an inner surface formed flat in the longitudinal direction; sealing the plate member, the fiber base material, the first member, and the second member by a sealing means, and evacuating an inside of the sealing means; impregnating the fiber base material with a resin; and heating and curing the resin to mold the long member.

According to a ninth invention to solve the above-described problems, in the composite material molding method according to the above-described eighth invention, the first member has an outer shape similar to a shape of the internal space.

According to a tenth invention to solve the above-described problems, in the composite material molding method according to the above-described eighth or ninth invention, the second member is provided over an entire length of the first member or is provided at a plurality of positions of a part of the entire length of the first member.

According to an eleventh invention to solve the above-described problems, in the composite material molding method according to any one of the above-described eighth to tenth inventions, a surface of the first member and a surface of the second member coming into contact with each other are coated with a mold release agent, are stuck with a mold release tape, or are subjected to mold release coating.

According to a twelfth invention to solve the above-described problems, in the composite material molding method according to any one of the above-described eighth to eleventh inventions, the first member is divided into two parts at a center in a width direction of the first member, and the second member is divided into two parts at a center in a width direction of the second member.

According to a thirteenth invention to solve the above-described problems, in the composite material molding method according to the above-described twelfth invention, in a case where the first member is divided in a longitudinal direction of the first member, one of the two parts divided in the width direction of the first member and another part are divided at different positions in the longitudinal direction.

According to a fourteenth invention to solve the above-described problems, in the composite material molding method according to the above-described twelfth or thirteenth invention, the second member has a triangular prism shape as a whole including the first member, and an angle member that has an L-shaped cross section and is fitted to a top part of the triangular prism shape is provided at the top part.

Advantageous Effects of Invention

According to the present invention, it is not necessary to uselessly divide the composite material molding jig in the longitudinal direction, and if the composite material molding jig is divided into parts, the parts can be disposed in contact with one another. This eliminates necessity of management of a gap, remarkably facilitates installation, and reduces a manufacturing cost. Further, a use amount of an alloy with low expansion coefficient, which is expensive, can be reduced and the manufacturing cost can be reduced because the outer shape of the first member is formed in a shape similar to the shape of the long member.

DESCRIPTION OF EMBODIMENTS

A composite material molding jig and a composite material molding method according to the present invention are described below with reference to drawings.

FIG.1is a cross-sectional view illustrating a composite material molding jig according to the present embodiment. Further,FIG.2is a perspective view illustrating a state where a part of first members constituting the composite material molding jig illustrated inFIG.1is disposed.FIG.3is a perspective view illustrating a state where all of the first members constituting the composite material molding jig illustrated inFIG.1are disposed.FIG.4is a perspective view illustrating a state where all of the first members and second members constituting the composite material molding jig illustrated inFIG.1are disposed.

A mandrel20(composite material molding jig) according to the present embodiment is also a mold for a raw (uncured) stringer12(long member) made of a fiber base material placed on a cured or raw (uncured) skin11(plate member). The mandrel20has a substantially triangular prism shape and has a substantially triangular cross-section. The stringer12has an inverted T-shaped cross-section. Therefore, the mandrel20internally includes an inverted T-shaped space S in a longitudinal direction. The stringer12has the inverted T-shape in this example; however, the stringer12may have the other shape. In this case, the shape of the space S is also changed depending on the shape of the stringer12. Note that, in an aircraft, the skin11constitutes, for example, a surface skin of a wing. For example, carbon fibers and glass fibers are used as the fiber base material.

In the present embodiment, the mandrel20is divided into first members21aand21bon an inside and second members22aand22bon an outside. Further, in this case, in consideration of change in a plate thickness of the stringer12during molding, the first members21aand21bare separable at a center in a width direction WD, and the second members22aand22bare also separable at the center in the width direction WD. Note that, in a case where the plate thickness is not changed, the first members21aand21bmay be integrally structured, and the second members22aand22bmay also be integrally structured.

In the first members21aand21b, the first member21ahas a substantially L-shaped cross-section, the first member21balso has a substantially L-shaped cross-section, and a space between the first member21aand the first member21bserves as a space S to form the stringer12. In other words, the space S serving as a mold of the stringer12is formed inside the whole of the first members21aand21b, and the outside of the whole of the first members21aand21bis formed in a shape similar to the space S.

Further, in the second members22aand22b, the second member22ahas a substantially triangular cross-section, the second member22balso has a substantially triangular cross-section, and a space between the second member22aand the second member22bserves as a space shaped to contain the first members21aand21b. In other words, the space shaped to contain the first members21aand21bis formed inside the whole of the second members22aand22b. In addition, the shape of the whole of the second members22aand22bincluding the first members21aand21bis a substantially triangular prism shape.

Further, in the case where the first members21aand21band the second members22aand22bare separated in the width direction WD, an angle member25that has a substantially L-shaped cross-section and is fitted to a top part of the mandrel20(first members21aand21band second members22aand22b) having the substantially triangular prism shape is preferably provided at the top part in order to prevent the first members21aand21band the second members22aand22bfrom falling down during formation of the stringer12.

Further, in the present embodiment, the first members21aand21bcoming into contact with the stringer12are made of a material having a thermal expansion coefficient substantially same as a thermal expansion coefficient of the stringer12, for example, a 36%-Ni alloy (invar material) as a low expansion alloy or CFRP. In contrast, the second members22aand22boutside the first members21aand21bare made of a material lighter than the material of the first members21aand21b, for example, an aluminum alloy.

Even when density of the material constituting the first members21aand21bis high, the weight of the first members21aand21bcan be reduced by forming the space S inside the first members21aand21b, forming the outside in a shape similar to the shape of the space S, and reducing the plate thickness as described above. Further, since the first members21aand21bare made of the material having the thermal expansion coefficient substantially same as the thermal expansion coefficient of the stringer12, it is not necessary to provide a gap in a longitudinal direction LD as with an existing technology, and it is not necessary to divide the first members21aand21bin the longitudinal direction LD.

However, if rigidity of the first members21aand21bis low, the first members21aand21bmay be bent during handling, demolding, or the like, and an accurately shaped product may not be manufactured. Therefore, it is necessary to design the first members21aand21bso as to achieve sufficient rigidity by themselves. Accordingly, the first members21aand21bpreferably have the cross-sectional shape high in cross-sectional secondary moment, such as a T-shape, an L-shape, and an I-shape, and preferably have a thickness of 2 mm or more.

The mandrel20thus configured eliminates necessity of division in the longitudinal direction LD. Therefore, it is not necessary to manage the gap, installation of the mandrel20becomes extremely easier, and a manufacturing cost can be reduced. For example, in a case where the mandrel is formed of an aluminum alloy in the existing technology, it is necessary to divide the mandrel into about five parts in order to manufacture the mandrel having a length of 5 m, and it is necessary to manage the gap at each of divided positions. In contrast, in the present embodiment, division of the mandrel20can be eliminated. Further, in a case of using an alloy with low expansion coefficient, which is expensive, the first members21aand21bare formed with a thickness enough to achieve sufficient rigidity, which makes it possible to reduce a use amount of the alloy with low expansion coefficient, and to reduce the manufacturing cost.

Note that if the first members21aand21bare each divided in the longitudinal direction LD in consideration of handling, demolding, and the like, the first member21ais divided into a first member21a-1and a first member21a-2at a dividing point Pa, and the first member21bis divided into a first member21b-1and a first member21b-2at a dividing point Pb at a position different from the position of the dividing point Pa. In other words, the first member21aand the first member21bare respectively divided at the dividing points Pa and Pb that are located at different positions in the longitudinal direction LD.

In the present embodiment, thermal strain may occur between the first members21aand21band the second members22aand22bduring formation (heating) of the stringer12. More specifically, thermal elongation of the second members22aand22boccurs because the thermal expansion coefficient of the second members22aand22bis higher than the thermal expansion coefficient of the first members21aand21b. If the first members21aand21bare moved due to thermal elongation of the second members22aand22b, the shape of the stringer12may be deformed. Accordingly, it is necessary for the second members22aand22bto slide in the longitudinal direction LD without restraining the first members21aand21b, to eliminate thermal strain.

Therefore, surfaces on the outside of the first members21aand21band surfaces on the inside of the second members22aand22b, namely, surfaces of the first members21aand21band surfaces of the second members22aand22bcoming into contact with each other are each formed flat without irregularity in the longitudinal direction LD. With such a configuration, the second members22aand22bcan slide in the longitudinal direction LD without restraining the first members21aand21b, and eliminate the thermal strain.

Further, each of the second members22aand22bmay have the length same as the length of each of the first members21aand21b, and may be provided over the entire length of the first members21aand21bas illustrated inFIG.4. Alternatively, as illustrated inFIG.5, the second members22aand22bmay be made up of a plurality of second members22a-1to22a-3and22b-1to22b-3each having a short length, and the plurality of second members22a-1to22a-3and22b-1to22b-3may be provided at a plurality of positions of a part of the entire length of the first members21aand21b. As described above, when the plurality of second members22a-1to22a-3and22b-1to22b-3each having the short length are used, sliding is facilitated to eliminate the thermal strain.

Note that in a case where the plurality of second members22a-1to22a-3and22b-1to22b-3are used and the first members21aand21bare also each divided in the longitudinal direction LD, any of the second members22a-1to22a-3and22b-1to22b-3is disposed at each of the dividing points Pa and Pb (for example, second members22a-2and22b-2are disposed inFIG.5). Further, the angle member25may be made up of a plurality of angle members each having a short length in matching with the plurality of second members22a-1to22a-3and22b-1to22b-3.

Further, thermal strain also occurs between the first members21aand21band the angle member25and between the second members22aand22band the angle member25. Accordingly, the surfaces of the first members21aand21band a surface of the angle member25coming into contact with each other and the surfaces of the second members22aand22band the surface of the angle member25coming into contact with each other are also each formed flat without irregularity in the longitudinal direction LD.

In addition, to improve slidability with respect to the thermal elongation, release treatment, for example, application of a silicon-based or fluorine-based mold release agent, sticking of a mold release tape made of tetrafluoroethylene, surface treatment such as mold release coating is preferably performed on the surfaces of the first members21aand21band the surfaces of the second members22aand22bcoming into contact with each other, on the surfaces of the first members21aand21band the surface of the angle member25coming into contact with each other, and on the surfaces of the second members22aand22band the surface of the angle member25coming into contact with each other.

Next, a composite material molding method using the mandrel20and the angle member25according to the present embodiment will be described with reference toFIGS.6A to6C.

First, as illustrated inFIG.6A, a cured or raw skin11is placed on a lower mold31, and a raw stringer12(fiber base material) is placed on the skin11. Further, the raw stringer12is placed in the space S inside the first members21aand21b, the first members21aand21bare placed in the space inside the second members22aand22b, and the angle member25is placed at the top part of the first members21aand21band the second members22aand22b. At the time of placement, the above-described release treatment may be performed. Further, the second members22aand22band the angle member25may be provided over the entire length of the first members21aand21bor at a plurality of positions of a part of the first members21aand21b.

After the mandrel20and the angle member25are disposed, a ring-shaped sealant32(sealing means) is attached to an end of the lower mold31, and a bagging film33(sealing means) is attached so as to cover the skin11, the stringer12, the mandrel20, and the angle member25inside the sealant32as illustrated inFIG.6B. The inside of the sealant32and the bagging film33is sealed in the above-described manner.

A vacuum apparatus is connected to one end of the bagging film33, and a resin injection apparatus is connected to the other end of the bagging film33. After the sealant32and the bagging film33are attached, the inside of the sealant32and the bagging film33is evacuated, a resin is injected into the inside of the sealant32and the bagging film33, and the raw skin11and the raw stringer12are impregnated with the resin. After impregnation of the resin, the whole body is heated by an oven or the like. As a result, the resin is cured and the skin11and the stringer12are molded (cured) (seeFIG.6C). As the resin, a thermosetting resin cured by heating, for example, an epoxy resin or polyimide is used.

Note that the molding method illustrated inFIGS.6A to6Cis suitable in a case where the skin11is raw. In a case where the skin11has been already cured, the lower mold31is unnecessary, and the stringer12can be molded by a molding method illustrated inFIG.7orFIG.8.

For example, in the molding method illustrated inFIG.7, the raw stringer12is placed on the cured skin11. The mandrel20and the angle member25are disposed in the manner described with reference toFIG.6A. Further, the ring-shaped sealant32is attached to an end of the cured skin11, and the bagging film33is attached so as to cover the stringer12, the mandrel20, and the angle member25inside the sealant32. In this case, the vacuum apparatus is connected to one end of the bagging film33, and the resin injection apparatus is connected to the other end of the bagging film33. After the sealant32and the bagging film33are attached, the inside of the sealant32and the bagging film33is evacuated, a resin is injected into the inside of the sealant32and the bagging film33, and the raw stringer12is impregnated with the resin. After impregnation of the resin, the whole body is heated by the oven. As a result, the resin is cured, and the stringer12is molded (cured).

Also in the molding method illustrated inFIG.8, the raw stringer12is placed on the cured skin11. The mandrel20and the angle member25are disposed in the manner described with reference toFIG.6A. Further, the ring-shaped sealant32is attached to each of a gap of the mandrel20, a gap between the mandrel20and the skin11, and a gap between the mandrel20and the angle member25, namely, to all of gaps around the stringer12. In this case, the vacuum apparatus is connected to one end of the mandrel20, and the resin injection apparatus is connected to the other end of the mandrel20. After the sealants32are attached, an inside of a part sealed by the sealants32is evacuated, a resin is injected into the inside of the part sealed by the sealants32, and the raw stringer12is impregnated with the resin. After impregnation of the resin, the whole body is heated by the oven. As a result, the resin is cured, and the stringer12is molded (cured).

FIGS.6A,6B,6C,7, and8described above each illustrate the sealant32as a sealing material; however, the other sealing material such as a sealing member may be used.

Further, each of the molding methods described inFIGS.6A,6B,6C,7, and8described above is called a Vacuum assisted Resin Transfer Molding (VaRTM); however, the mandrel20and the angle member25according to the present embodiment are usable in a vacuum heat molding, autoclave molding, or the like of a prepreg without being limited to the above-described methods.

INDUSTRIAL APPLICABILITY

The present invention is usable for the whole of the composite material application member.

REFERENCE SIGNS LIST