Composite material structure, working machine, and method of forming composite material structure

Abstract

To achieve a structure with high rigidity while suppressing strength reduction.SOLUTION: In a composite material structure formed by laminating a plurality of reinforced fiber sheets and formed to extend in a lengthwise direction, and having a bent portion bent in a perpendicular direction perpendicular to the lengthwise direction, the reinforced fiber sheets include a 0-degree layer reinforced fiber sheet being the reinforced fiber sheet with a fiber direction extending in the lengthwise direction, and a crossing layer reinforced fiber sheet being the reinforced fiber sheet with a fiber direction extending in a crossing direction that crosses the lengthwise direction. The elastic modulus of the reinforced fiber sheet of the crossing layer is lower than the elastic modulus of the 0-degree layer reinforced fiber sheet.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a composite material structure, a working machine, and a method for forming a composite material structure.

Background Art

[0002] Conventionally, as a composite material structure, a long part provided in a working machine is known (see, for example, Patent Document 1). This long part has a curved part with a predetermined curvature, and a cross-section cut by a plane orthogonal to the longitudinal direction is concave. The long part is formed into a concave cross-sectional shape by forming a composite material, which is a laminate obtained by laminating reinforcing fiber sheets, using a forming jig.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to improve the rigidity of a composite material structure such as the long part of Patent Document 1, it is conceivable to use high-rigidity reinforcing fibers as the reinforcing fibers contained in the reinforcing fiber sheet. However, since high-rigidity reinforcing fibers are difficult to bend during the molding of the composite material, at least one of wrinkles, delamination, and fiber breakage may occur in the curved part, which may lead to a decrease in the strength of the composite material structure.

[0005] Therefore, an object of the present disclosure is to provide a composite material structure, a working machine, and a method for forming a composite material structure that can have a high-rigidity structure while suppressing a decrease in strength.

Means for Solving the Problems

[0006] The composite material structure of the present disclosure is formed by laminating a plurality of reinforcing fiber sheets, extends in the longitudinal direction, and has a bent portion bent in the orthogonal direction orthogonal to the longitudinal direction. In the composite material structure, the reinforcing fiber sheet includes a reinforcing fiber sheet of a 0° layer in which the fiber direction extends in the longitudinal direction and a reinforcing fiber sheet of an intersecting layer in which the fiber direction extends in the intersecting direction intersecting the longitudinal direction. The elastic modulus of the reinforcing fiber sheet of the intersecting layer is lower than the elastic modulus of the reinforcing fiber sheet of the 0° layer.

[0007] Another composite material structure of the present disclosure is formed by laminating a plurality of reinforcing fiber sheets, extends in the longitudinal direction, and has a bent portion bent in the orthogonal direction orthogonal to the longitudinal direction. In the composite material structure, a stress absorber is provided between the layers of the reinforcing fiber sheet in the bent portion to absorb the stress generated in the bent portion.

[0008] The working machine of the present disclosure includes the above composite material structure.

[0009] The molding method of the composite material structure of the present disclosure is a molding method of a composite material structure formed to extend in the longitudinal direction and having a bent portion bent in the orthogonal direction orthogonal to the longitudinal direction. The method includes a laminating step of laminating a plurality of reinforcing fiber sheets. In the laminating step, a reinforcing fiber sheet of a 0° layer in which the fiber direction extends in the longitudinal direction and a reinforcing fiber sheet of an intersecting layer in which the fiber direction extends in the intersecting direction intersecting the longitudinal direction are laminated. The elastic modulus of the reinforcing fiber sheet of the intersecting layer is lower than the elastic modulus of the reinforcing fiber sheet of the 0° layer.

[0010] Another molding method of the composite material structure of the present disclosure is a molding method of a composite material structure formed to extend in the longitudinal direction and having a bent portion bent in the orthogonal direction orthogonal to the longitudinal direction. The method includes a laminating step of laminating a plurality of reinforcing fiber sheets and a curing step of curing the laminate formed by laminating the reinforcing fiber sheets. The steps from the laminating step to the curing step are repeated a plurality of times to mold the composite material structure.

[0011] Another method for forming a composite material structure of the present disclosure is a method for forming a composite material structure that is formed to extend in the longitudinal direction and has a bent portion bent in the orthogonal direction orthogonal to the longitudinal direction. The method includes a laminating step of laminating a plurality of reinforcing fiber sheets. In the laminating step, a stress absorber that absorbs the stress generated in the bent portion is disposed between the layers of the reinforcing fiber sheets in the bent portion.

Advantages of the Invention

[0012] According to the present disclosure, it is possible to obtain a structure with high rigidity while suppressing a decrease in strength.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited by these embodiments. Also, the components in the following embodiments include those that can be replaced and are easy for those skilled in the art, or those that are substantially the same. Furthermore, the components described below can be combined as appropriate, and when there are multiple embodiments, the embodiments can also be combined with each other.

[0015] [First Embodiment] The composite material structure according to the first embodiment is, for example, a structure provided in the working machine 10 and is formed by laminating reinforcing fiber sheets such as prepregs. First, the working machine 10 will be described with reference to FIG. 1. FIG. 1 is an external perspective view of a working machine equipped with the composite material structure according to the first embodiment.

[0016] (Working Machine) As shown in FIG. 1, the working machine 10 includes a fixed part 11, a long part 12 as a composite material structure, and an arm 13. Also, the working machine 10 is provided with a transport rail 15 that extends from the fixed part 11 to the tip of the long part 12. In this working machine 10, by using the transport rail 15, objects are transported inside and outside the furnace, and the arm 13 is loaded and unloaded.

[0017] The fixing part 11 is fixed to a fixed structure. A long part 12 is connected to the fixing part 11 and supports the long part 12 so as to be movable in the vertical direction. The fixing part 11 is provided with a connecting part 21 to which the long part 12 is connected, and a plurality (for example, two in Embodiment 1) of actuators 22 for inclining the long part 12. The connecting part 21 is provided on the lower surface side (fixed structure side) of the fixing part 11 and is formed such that the direction orthogonal to the longitudinal direction of the long part 12 becomes the direction of the rotation axis. The actuator 22 is provided on the upper side of the fixing part 11, that is, on the opposite side of the fixed structure with the connecting part 21 interposed therebetween, and changes the distance between the fixing part 11 and the long part 12. For this reason, the fixing part 11 changes the distance between the fixing part 11 and the long part 12 by the actuator 22, so that the long part 12 rotates about the rotation axis of the connecting part 21, and the tip side of the long part 12 moves in the vertical direction.

[0018] The long part 12 is connected to the fixing part 11. That is, as described above, the long part 12 is connected to the fixing part 11 so as to be tiltable. Further, the long part 12 is provided so as to extend in the longitudinal direction. The long part 12 is a telescopic structure having a plurality of stages, and in the first embodiment, for example, it is a three-stage telescopic structure.

[0019] The long part 12 is formed using a composite material and is formed to extend in the longitudinal direction. The composite material is formed by laminating reinforcing fiber sheets P, and the reinforcing fiber sheet P is, for example, a prepreg containing reinforcing fibers and a resin impregnated in the reinforcing fibers.

[0020] The arm 13 is connected to the tip side of the long part 12 and is a tool capable of performing various operations related to the decommissioning process.

[0021] The transport rail 15 is provided from the fixed part 11 to the long part 12. Further, the transport rail 15 is provided along the longitudinal direction on the bottom surface of the long part 12. A plurality of sets of a pair of parallel rails are provided for the transport rail 15, and they are provided extending in the longitudinal direction of the long part 12. Note that the transport rail 15 is used to transport a storage box for storing the processed materials generated in the decommissioning process.

[0022] (Composite material structure (long part)) Next, referring to FIG. 2, the long part 12 as a composite material structure will be described. FIG. 2 is a cross-sectional view schematically showing the composite material structure according to the first embodiment. As shown in FIG. 2, the long part 12 has a curved part 31 with a predetermined curvature. Further, the long part 12 is formed by laminating a plurality of reinforcing fiber sheets and is formed extending in the longitudinal direction. The curved part 31 is formed by bending in the orthogonal direction orthogonal to the longitudinal direction. The reinforcing fiber sheet P is a unidirectional material with the fiber directions aligned in one direction, and is a sheet containing carbon fiber and thermosetting resin.

[0023] The plurality of laminated reinforcing fiber sheets P include a 0° layer reinforcing fiber sheet P with the fiber direction arranged along the longitudinal direction and an intersecting layer reinforcing fiber sheet P with the fiber direction arranged along the intersecting direction intersecting the longitudinal direction. As the intersecting layer reinforcing fiber sheet P, it includes a 90° layer reinforcing fiber sheet P with the fiber direction extending in the orthogonal direction orthogonal to the longitudinal direction and a ±45° layer reinforcing fiber sheet P with the fiber direction extending in the direction inclined by ±45° with respect to the longitudinal direction.

[0024] For the 0° layer reinforcing fiber sheet P, high-rigidity carbon fiber is used, and pitch-based carbon fiber is used. The ratio of the 0° layer reinforcing fiber sheet P to all the reinforcing fiber sheets is 25% or more.

[0025] The elastic modulus of the reinforcing fiber sheet P of the 90° layer is lower than that of the reinforcing fiber sheet P of the 0° layer. Specifically, the elastic modulus of the reinforcing fiber sheet P of the 90° layer is 500 GPa or less, preferably 300 GPa or less. As the reinforcing fiber sheet P of the 90° layer, PAN-based carbon fiber is used. Also, the ratio of the reinforcing fiber sheet P of the 90° layer to all the reinforcing fiber sheets P is in the range of 10% to 25%.

[0026] The elastic modulus of the reinforcing fiber sheet P of the ±45° layer is equal to or lower than that of the reinforcing fiber sheet P of the 0° layer. Specifically, the elastic modulus of the reinforcing fiber sheet P of the ±45° layer may be 500 GPa or less, similar to the reinforcing fiber sheet of the 90° layer, or the same as that of the reinforcing fiber sheet P of the 0° layer may be used. That is, as long as the elastic modulus of the reinforcing fiber sheet P of the ±45° layer is equal to or lower than that of the reinforcing fiber sheet P of the 0° layer, pitch-based carbon fiber or PAN-based carbon fiber may be used. Also, the ratio of the reinforcing fiber sheet P of the ±45° layer to all the reinforcing fiber sheets P is in the range of 40% to 50%.

[0027] In the first embodiment, as the reinforcing fiber sheet P of the cross layer, the reinforcing fiber sheet P of the 90° layer and the reinforcing fiber sheet P of the ±45° layer are applied, but the configuration is not particularly limited thereto. As the reinforcing fiber sheet P of the cross layer, a reinforcing fiber sheet P of the ±60° layer in which the fiber direction extends in a direction inclined by ±60° with respect to the longitudinal direction may be applied. In this case, the elastic modulus of the reinforcing fiber sheet P of the ±60° layer is lower than that of the reinforcing fiber sheet P of the 0° layer, and PAN-based carbon fiber is used as in the reinforcing fiber sheet P of the 90° layer.

[0028] Further, the plurality of reinforcing fiber sheets P include a glass fiber sheet P2 provided on the outermost surface. The glass fiber sheets P2 are respectively provided on the innermost side and the outermost side of the bent portion 31, and the reinforcing fiber sheet P sandwiched between the innermost and outermost glass fiber sheets P2 is a carbon fiber sheet P1. Glass fiber has higher toughness than carbon fiber and suppresses the generation of cracks on the outermost surface of the long portion 12. In the first embodiment, the glass fiber sheet P2 is applied, but any sheet containing fibers with higher toughness than carbon fiber may be used. For example, instead of the glass fiber sheet P2, a sheet containing organic fibers such as aramid fiber may be applied.

[0029] (Forming method of composite material structure (long portion)) Next, with reference to FIG. 3, the forming method of the long portion 12 will be described. In the forming method of the long portion 12, a step S1 of cutting the reinforcing fiber sheet P before curing into a predetermined size is executed. Subsequently, in the forming method, a step S2 (lamination step) of laminating the cut reinforcing fiber sheet P is executed using a mold 41 serving as a convex male mold (see FIG. 2). In step S2, a plurality of reinforcing fiber sheets P (P1, P2) are laminated so as to have the above-described laminated structure. That is, in step S2, the reinforcing fiber sheet P of the 0° layer, the reinforcing fiber sheet P of the 90° layer that is more flexible than the reinforcing fiber sheet P of the 0° layer, and the reinforcing fiber sheet P of the ±45° layer are laminated so as to satisfy the above ratio. Further, in step S2, when laminating the reinforcing fiber sheet P, the reinforcing fiber sheet P is handled so that the reinforcing fiber sheet P does not bend locally. In step S2, the reinforcing fiber sheet P is heated to a temperature at which the resin contained in the reinforcing fiber sheet P becomes flexible, and the reinforcing fiber sheet P is laminated while being shaped along the mold 41. Further, in step S2, when laminating the reinforcing fiber sheet P, the wrinkles generated in the bent portion 31 are removed by roller application to the bent portion 31.

[0030] In step S2, when laminating the reinforcing fiber sheets P, in the molding method, for each predetermined number of laminations, a compaction is performed to make the reinforcing fiber sheets P adhere to each other and harden (step S3). In step S3, for example, for every four layers, the laminated reinforcing fiber sheets P are sealed with a vacuum bag and evacuated to degas the air between the layers. Steps S2 and S3 are repeatedly executed until the predetermined number of laminations is reached.

[0031] After the execution of step S3, in the molding method, the laminate in which all the reinforcing fiber sheets P are laminated is sealed with a vacuum bag and evacuated, and the laminate is accommodated in an autoclave, and step S4 (curing step) of thermally curing the laminate while applying pressure and heating in the autoclave is executed. In step S4, the laminate is completely cured. After the execution of step S4, the long portion 12 as the composite material structure is formed, and a series of steps related to the molding method are completed.

[0032] [Second Embodiment] Next, with reference to FIGS. 4 and 5, the second embodiment will be described. FIG. 4 is a cross-sectional view schematically showing the composite material structure according to the second embodiment. FIG. 5 is a flowchart of the molding method of the composite material structure according to the second embodiment. In the second embodiment, in order to avoid redundant description, the parts different from the first embodiment will be described, and the parts having the same configuration as the first embodiment will be described with the same reference numerals.

[0033] (Molding Method of Composite Material Structure (Long Portion)) The molding method of the long portion 12 in the second embodiment repeatedly executes the steps from the lamination step S2 to the curing step S4 in the first embodiment a plurality of times to form the long portion 12. Also, the molding method of the long portion 12 in the second embodiment is a method in which the way of applying the roller in the lamination step is different and a hot compaction step is added.

[0034] In the method for forming the long member 12, similar to the first embodiment, a step S1 of cutting the reinforcing fiber sheet P before curing into a predetermined size is executed. Subsequently, in the forming method, a step S2 (lamination step) of laminating the cut reinforcing fiber sheet P is executed using a forming die (see FIG. 4) 41 that becomes a convex male die. In step S2, the reinforcing fiber sheet P1b located inside the long member 12 is laminated. That is, in step S2, instead of laminating all the reinforcing fiber sheets P, a part of the reinforcing fiber sheets P1b is laminated. In the second embodiment, for example, the reinforcing fiber sheet P1b is laminated up to half the thickness of the long member 12. Also, in step S2, when laminating the reinforcing fiber sheet, wrinkles generated in the bent portion 31 are removed by rolling from the central portion of the reinforcing fiber sheet toward the end portion via the bent portion 31. Note that other processes in step S2 are the same as those in the first embodiment.

[0035] In step S2, when the reinforcing fiber sheet P is laminated, in the forming method, a compaction for closely adhering the reinforcing fiber sheets to each other is executed for each predetermined number of laminations (step S3a). Since step S3a of the second embodiment is the same as step S3 of the first embodiment, the description thereof is omitted.

[0036] After the execution of step S3a, in the forming method, a hot compaction for closely adhering the reinforcing fiber sheets to each other while heating the reinforcing fiber sheets to make the resin flow is executed for each predetermined number of laminations (step S3b). In step S3b, for example, for every 8 layers, the laminated reinforcing fiber sheets are sealed with a vacuum bag and vacuumed while heating to degas the air between the layers and reduce the thickness.

[0037] After the execution of step S3b, in the forming method, a laminate in which a part of the reinforcing fiber sheets P is laminated is sealed with a vacuum bag and vacuumed, and the laminate is accommodated in an autoclave, and a step S4 (curing step) of thermally curing the laminate while pressurizing and heating in the autoclave is executed. In step S4, the laminate is completely cured.

[0038] After the execution of step S4, in the forming method, it is determined whether or not all the reinforcing fiber sheets P are laminated (step S6). If it is determined that all are laminated (step S6: Yes), assuming that the long portion 12 as the composite material structure is formed, a series of steps regarding the forming method are completed.

[0039] On the other hand, in step S6, if it is determined that not all are laminated (step S6: No), the process returns to step S2 again, and steps S2 to S4 are repeatedly executed. For example, in step S6, if it is determined that not all are laminated (step S6: No), the process proceeds to step S2, and the reinforcing fiber sheet P1a located outside the long portion 12 is laminated. That is, in step S2, the remaining reinforcing fiber sheet P1a is laminated.

[0040] [Third Embodiment] Next, referring to FIG. 6, the third embodiment will be described. FIG. 6 is a cross-sectional view schematically showing the composite material structure according to the third embodiment. In the third embodiment as well, in order to avoid redundant description, parts different from the first and second embodiments will be described, and parts having the same configuration as the first and second embodiments will be described with the same reference numerals.

[0041] (Composite Material Structure (Long Portion)) In the long portion 12 of the third embodiment, a stress absorber 51 is provided between the layers of the reinforcing fiber sheet P in the bent portion 31. The stress absorber 51 is a material that absorbs the stress generated in the bent portion 31. For example, rubber, a reinforcing fiber sheet containing organic fibers, a reinforcing fiber sheet containing carbon fibers with a low elastic modulus, etc. are used. The stress absorber 51 may be arranged by replacing a part of the reinforcing fiber sheet of the 90° layer in the first embodiment in the bent portion 31.

[0042] Note that the stress absorber 51 may or may not be combined with the first and second embodiments.

[0043] Next, with reference to FIG. 7, the performance of the composite material structure will be described. FIG. 7 is an explanatory diagram showing an example of the performance of the composite material structure. The composite materials A and B shown in FIG. 7 have different carbon fibers used for the reinforcing fiber sheets of the 0° layer, and the rigidity in the longitudinal direction of composite material B is higher than that of composite material A. Note that the carbon fibers used for the reinforcing fiber sheets of the 90° layer and the ±45° layer are the same. The reinforcing fiber sheet of the 90° layer contains PAN-based carbon fibers, and the reinforcing fiber sheet of the 0° layer contains pitch-based carbon fibers.

[0044] In composite material A, it was confirmed by analysis that while suppressing the occurrence of wrinkles or delamination in the bent portion 31, the minimum value of the deformation amount in the longitudinal direction is 6.7% larger than that of SUS having an equivalent shape. Also, in composite material B, it was confirmed by analysis that while suppressing the occurrence of wrinkles or delamination in the bent portion 31, the minimum value of the deformation amount in the longitudinal direction is almost the same as that of SUS having an equivalent shape.

[0045] As described above, the composite material structure, the working machine, and the forming method of the composite material structure according to the first to third embodiments can be understood as follows, for example.

[0046] The composite material structure according to the first aspect is formed by laminating a plurality of reinforcing fiber sheets P and extends in the longitudinal direction, and has a bent portion 31 bent in a direction orthogonal to the longitudinal direction (longitudinal portion 12). In the composite material structure, the reinforcing fiber sheet P includes a 0° layer reinforcing fiber sheet P in which the fiber direction extends in the longitudinal direction and an intersecting layer reinforcing fiber sheet P in which the fiber direction extends in an intersecting direction intersecting the longitudinal direction, and the elastic modulus of the intersecting layer reinforcing fiber sheet P is lower than the elastic modulus of the 0° layer reinforcing fiber sheet P.

[0047] According to this configuration, by reducing the elastic modulus of the reinforcing fiber sheet P of the cross layer, the bending of the bent portion 31 during molding can be tolerated, so that a strength reduction due to molding defects is not caused. Further, since the elastic modulus of the reinforcing fiber sheet P of the 0° layer can be increased, the rigidity in the longitudinal direction can be maintained at a high level. Therefore, the composite material structure can have a high-rigidity structure while suppressing a strength reduction.

[0048] As a second aspect, in the composite material structure according to the first aspect, the reinforcing fiber sheet P of the cross layer has an elastic modulus of 500 GPa or less.

[0049] According to this configuration, since the reinforcing fiber sheet P of the cross layer can be given an appropriate elastic modulus that allows bending, molding defects in the bent portion 31 can be suppressed.

[0050] As a third aspect, in the composite material structure according to the first or second aspect, the reinforcing fiber sheet of the cross layer contains PAN-based carbon fiber.

[0051] According to this configuration, since an appropriate material that allows bending can be used as the reinforcing fiber sheet P of the cross layer, molding defects in the bent portion 31 can be suppressed.

[0052] As a fourth aspect, in the composite material structure according to any one of the first to third aspects, the ratio of the reinforcing fiber sheet P of the 0° layer to all the reinforcing fiber sheets P is 25% or more.

[0053] According to this configuration, since the ratio of the reinforcing fiber sheet P of the 0° layer can be set to an appropriate ratio, the rigidity in the longitudinal direction can be maintained at a high level.

[0054] As a fifth aspect, in the composite material structure according to any one of the first to fourth aspects, the reinforcing fiber sheet P of the cross layer is the reinforcing fiber sheet P of the 90° layer in which the fiber direction extends in the orthogonal direction orthogonal to the longitudinal direction, and the reinforcing fiber sheet P of the ±45° layer in which the fiber direction extends in a direction inclined by ±45° with respect to the longitudinal direction, and the elastic modulus of the reinforcing fiber sheet P of the 90° layer is lower than the elastic modulus of the reinforcing fiber sheet P of the 0° layer, and the elastic modulus of the reinforcing fiber sheet P of the ±45° layer is equal to or less than the elastic modulus of the reinforcing fiber sheet P of the 0° layer.

[0055] According to this configuration, even when the reinforcing fiber sheet P of the 90° layer and the reinforcing fiber sheet P of the ±45° layer are used as the reinforcing fiber sheet P of the cross layer, it is possible to obtain a high-rigidity structure while suppressing a decrease in strength.

[0056] As a sixth aspect, in the composite material structure according to the fifth aspect, the reinforcing fiber sheet P of the 90° layer contains PAN-based carbon fibers.

[0057] According to this configuration, since the reinforcing fiber sheet P of the 90° layer can have an appropriate elastic modulus that allows bending, it is possible to suppress molding defects in the bent portion 31.

[0058] As a seventh aspect, in the composite material structure according to the fifth or sixth aspect, the ratio of the reinforcing fiber sheet P of the 90° layer to all the reinforcing fiber sheets P is in the range of 10% to 25%.

[0059] According to this configuration, since the ratio of the reinforcing fiber sheet P of the 90° layer can be set to an appropriate ratio, it is possible to suppress molding defects in the bent portion 31.

[0060] As an eighth aspect, in the composite material structure according to any one of the fifth to seventh aspects, the ratio of the reinforcing fiber sheet P of the ±45° layer to all the reinforcing fiber sheets P is in the range of 40% to 50%.

[0061] According to this configuration, since the ratio of the reinforcing fiber sheet P of the ±45° layer can be set to an appropriate ratio, it is possible to suppress a decrease in rigidity in the longitudinal direction and suppress molding defects in the bent portion 31.

[0062] As a ninth aspect, in the composite material structure according to any one of the first to fourth aspects, the reinforcing fiber sheet P of the cross layer includes the reinforcing fiber sheet P of the ±60° layer in which the fiber direction extends in a direction inclined by ±60° with respect to the longitudinal direction, and the elastic modulus of the reinforcing fiber sheet P of the ±60° layer is lower than the elastic modulus of the reinforcing fiber sheet P of the 0° layer.

[0063] According to this configuration, even when the reinforcing fiber sheet P of the ±60° layer is used as the reinforcing fiber sheet P of the cross layer, it is possible to obtain a high-rigidity structure while suppressing a decrease in strength.

[0064] As a tenth aspect, in the composite material structure according to the ninth aspect, the reinforcing fiber sheet of the ±60° layer contains PAN-based carbon fibers.

[0065] According to this configuration, since an appropriate material capable of allowing bending can be used as the reinforcing fiber sheet P of the ±60° layer, molding defects in the bent portion 31 can be suppressed.

[0066] As an eleventh aspect, in the composite material structure according to any one of the first to tenth aspects, a stress absorber 51 is provided between the layers of the reinforcing fiber sheet P in the bent portion 31 to absorb the stress generated in the bent portion 31.

[0067] According to this configuration, by absorbing the stress generated in the bent portion 31 by the stress absorber 51, bending during molding can be allowed, so that molding defects can be further suppressed.

[0068] As a twelfth aspect, in the composite material structure according to any one of the first to eleventh aspects, the reinforcing fiber sheet P provided on the outermost surface is a sheet containing fibers having higher toughness than carbon fibers.

[0069] According to this configuration, the generation of cracks on the outermost surface and the propagation of the cracks generated on the outermost surface can be suppressed, and the strength reduction due to the cracks can be suppressed.

[0070] The composite material structure according to the 13th aspect is a composite material structure formed by laminating a plurality of reinforcing fiber sheets P and extending in the longitudinal direction, and having a bent portion 31 bent in the orthogonal direction orthogonal to the longitudinal direction. A stress absorber 51 is provided between the layers of the reinforcing fiber sheet P in the bent portion 31 to absorb the stress generated in the bent portion 31.

[0071] According to this configuration, by absorbing the stress generated in the bent portion 31 by the stress absorber 51, bending during molding can be tolerated, so that a strength reduction due to molding defects is not caused. In addition, since it is possible to increase the rigidity in the longitudinal direction, the composite material structure can be made into a high-rigidity structure while suppressing strength reduction.

[0072] The working machine according to the 14th aspect includes the above-described composite material structure.

[0073] According to this configuration, it is possible to provide a working machine 10 using a composite material structure having high rigidity in the longitudinal direction.

[0074] The method for forming a composite material structure according to the 15th aspect is a method for forming a composite material structure formed by extending in the longitudinal direction and having a bent portion 31 bent in the orthogonal direction orthogonal to the longitudinal direction. The method includes a laminating step S2 of laminating a plurality of reinforcing fiber sheets P. In the laminating step S2, a 0° layer reinforcing fiber sheet P in which the fiber direction extends in the longitudinal direction and a reinforcing fiber sheet P of an intersecting layer in which the fiber direction extends in an intersecting direction intersecting the longitudinal direction are laminated, and the elastic modulus of the reinforcing fiber sheet P of the intersecting layer is lower than the elastic modulus of the reinforcing fiber sheet P of the 0° layer.

[0075] According to this configuration, by reducing the elastic modulus of the reinforcing fiber sheet P of the cross layer, bending of the bent portion 31 during molding can be tolerated, so that a decrease in strength due to molding defects is not caused. Further, since the elastic modulus of the reinforcing fiber sheet P of the 0° layer can be increased, the rigidity in the longitudinal direction can be maintained at a high level. Therefore, the composite material structure can be made into a high-rigidity structure while suppressing a decrease in strength.

[0076] As a 16th aspect, in the method for molding a composite material structure according to the 15th aspect, the method further includes a curing step S4 of curing the laminate formed by laminating the reinforcing fiber sheets P, and the steps from the laminating step S2 to the curing step S4 are repeated a plurality of times to mold the composite material structure.

[0077] According to this configuration, by curing the composite material structure in multiple stages, the stress for correcting spring-in generated during curing is reduced, so that delamination can be reduced, and thus a decrease in strength due to molding defects is not caused. Therefore, the composite material structure can be made into a high-rigidity structure while suppressing a decrease in strength.

[0078] As a 17th aspect, in the method for molding a composite material structure according to the 15th or 16th aspect, in the laminating step S2, a stress absorber 51 that absorbs the stress generated in the bent portion 31 is disposed between the layers of the reinforcing fiber sheet P in the bent portion 31.

[0079] According to this configuration, by absorbing the stress generated in the bent portion 31 by the stress absorber 51, bending during molding can be tolerated, so that molding defects can be further suppressed.

[0080] The method for forming a composite material structure according to the 18th aspect is a method for forming a composite material structure having a bent portion 31 formed to extend in the longitudinal direction and bent in the orthogonal direction orthogonal to the longitudinal direction, including a lamination step S2 of laminating a plurality of reinforcing fiber sheets P, and a curing step S4 of curing the laminate formed by laminating the reinforcing fiber sheets P, and repeating the steps from the lamination step S2 to the curing step S4 a plurality of times to form the composite material structure.

[0081] According to this configuration, by curing the composite material structure in multiple stages, the stress for correcting the spring-in generated during curing is reduced, so that delamination can be reduced, and a decrease in strength due to molding defects can be avoided. Therefore, the composite material structure can have a high-rigidity structure while suppressing a decrease in strength.

[0082] The method for forming a composite material structure according to the 19th aspect is a method for forming a composite material structure having a bent portion 31 formed to extend in the longitudinal direction and bent in the orthogonal direction orthogonal to the longitudinal direction, including a lamination step S2 of laminating a plurality of reinforcing fiber sheets P, and in the lamination step S2, a stress absorber 51 for absorbing the stress generated in the bent portion 31 is disposed between the layers of the reinforcing fiber sheet P in the bent portion 31.

[0083] According to this configuration, since the stress absorber 51 absorbs the stress generated in the bent portion 31, bending during molding can be tolerated, and a decrease in strength due to molding defects can be avoided. In addition, since the rigidity in the longitudinal direction can be increased, the composite material structure can have a high-rigidity structure while suppressing a decrease in strength.

Explanation of Signs

[0084] 10 Working machine 11 Fixed part 12 Long part 13 Arm 15 Conveyor rail 21 Connecting part 22 Actuator 31 Bent portion 41 Forming die 51 Stress absorber

Claims

1. In a composite material structure formed by laminating a plurality of reinforcing fiber sheets, extending in the longitudinal direction, and having a bent portion bent in the orthogonal direction orthogonal to the longitudinal direction, the reinforcing fiber sheet is a reinforcing fiber sheet of a 0° layer that is a reinforcing fiber sheet in which the fiber direction extends in the longitudinal direction, and a reinforcing fiber sheet of an intersecting layer that is a reinforcing fiber sheet in which the fiber direction extends in an intersecting direction intersecting the longitudinal direction, and includes a composite material structure in which the elastic modulus of the reinforcing fiber sheet of the intersecting layer is lower than the elastic modulus of the reinforcing fiber sheet of the 0° layer.

2. The composite material structure according to claim 1, wherein the reinforcing fiber sheet of the intersecting layer has an elastic modulus of 500 GPa or less.

3. The composite material structure according to claim 2, wherein the reinforcing fiber sheet of the intersecting layer contains PAN-based carbon fiber.

4. The composite material structure according to claim 1, wherein the ratio of the reinforcing fiber sheet of the 0° layer to all the reinforcing fiber sheets is 25% or more.

5. The reinforcing fiber sheet of the intersecting layer is a reinforcing fiber sheet of a 90° layer that is a reinforcing fiber sheet in which the fiber direction extends in the orthogonal direction orthogonal to the longitudinal direction, and a reinforcing fiber sheet of a ±45° layer that is a reinforcing fiber sheet in which the fiber direction extends in a direction inclined by ±45° with respect to the longitudinal direction, and includes the elastic modulus of the reinforcing fiber sheet of the 90° layer is lower than the elastic modulus of the reinforcing fiber sheet of the 0° layer, The composite material structure according to claim 1, wherein the elastic modulus of the reinforcing fiber sheet of the ±45° layer is equal to or less than the elastic modulus of the reinforcing fiber sheet of the 0° layer.

6. The composite material structure according to claim 5, wherein the reinforcing fiber sheet of the 90° layer contains PAN-based carbon fiber.

7. The composite material structure according to claim 5, wherein the ratio of the reinforcing fiber sheet of the 90° layer to all the reinforcing fiber sheets is in the range of 10% to 25%.

8. The composite material structure according to claim 5, wherein the ratio of the reinforcing fiber sheet of the ±45° layer to all the reinforcing fiber sheets is in the range of 40% to 50%.

9. The reinforcing fiber sheet of the intersecting layer is a reinforcing fiber sheet of a ±60° layer that is a reinforcing fiber sheet in which the fiber direction extends in a direction inclined by ±60° with respect to the longitudinal direction, and includes The composite material structure according to claim 1, wherein the elastic modulus of the reinforcing fiber sheet of the ±60° layer is lower than the elastic modulus of the reinforcing fiber sheet of the 0° layer.

10. The reinforcing fiber sheet of the ±60° layer is the composite material structure according to claim 9, which contains PAN-based carbon fiber.

11. The composite material structure according to claim 1, further comprising a stress absorber provided between layers of the reinforcing fiber sheet in the bent portion to absorb stress generated in the bent portion.

12. The composite material structure according to claim 1, wherein the reinforcing fiber sheet provided on the outermost surface is a sheet containing fibers with higher toughness than carbon fibers.

13. In a composite material structure formed by laminating a plurality of reinforcing fiber sheets, extending in the longitudinal direction, and having a bent portion bent in a direction orthogonal to the longitudinal direction, The composite material structure further comprising a stress absorber provided between layers of the reinforcing fiber sheet in the bent portion to absorb stress generated in the bent portion.

14. A working machine comprising the composite material structure according to any one of claims 1 to 13.

15. In a method for forming a composite material structure that extends in the longitudinal direction and has a bent portion bent in a direction orthogonal to the longitudinal direction, The method includes a laminating step of laminating a plurality of reinforcing fiber sheets, In the laminating step, A 0° layer reinforcing fiber sheet, which is a reinforcing fiber sheet with a fiber direction extending in the longitudinal direction, and An intersecting layer reinforcing fiber sheet, which is a reinforcing fiber sheet with a fiber direction extending in an intersecting direction intersecting the longitudinal direction, are laminated, A method for forming a composite material structure, wherein the elastic modulus of the reinforcing fiber sheet of the intersecting layer is lower than the elastic modulus of the reinforcing fiber sheet of the 0° layer.

16. The method further includes a curing step of curing the laminate formed by laminating the reinforcing fiber sheets, The method for forming a composite material structure according to claim 15, wherein the steps from the laminating step to the curing step are repeated a plurality of times to form the composite material structure.

17. In the laminating step, A stress absorber for absorbing stress generated in the bent portion is disposed between layers of the reinforcing fiber sheet in the bent portion. The method for forming a composite material structure according to claim 15.

18. In a method for forming a composite material structure that extends in the longitudinal direction and has a bent portion bent in a direction orthogonal to the longitudinal direction, A laminating step of laminating a plurality of reinforcing fiber sheets and A curing step of curing the laminate formed by laminating the reinforcing fiber sheets, A method for forming a composite material structure, wherein the steps from the laminating step to the curing step are repeated a plurality of times to form the composite material structure.

19. In a method for forming a composite material structure that extends in the longitudinal direction and has a bent portion bent in the orthogonal direction orthogonal to the longitudinal direction, including a lamination step of laminating a plurality of reinforcing fiber sheets, in the lamination step, A method for forming a composite material structure in which a stress absorber that absorbs the stress generated in the bent portion is disposed between the layers of the reinforcing fiber sheet in the bent portion.

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