Joining method and joint structure

Abstract

To provide a joint structure which is lightweight and has excellent rigidity.SOLUTION: A joint structure 200 includes: a first member 210 including a first thermoplastic resin; a second member 220 including a second thermoplastic resin; a first surface 232 on which a first metal oxide particle cluster 236 is formed, which is bonded to the first resin of the first member 210; a second surface 234 on which a second metal oxide particle cluster 238 is formed, which is bonded to the second resin of the second member 220; and a metal member 230 having a thickness from the first surface 232 to the second surface 234 of 5 μm or more and 1 mm or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a joining method and a joined structure. [Background technology]

[0002] In recent years, structural members using fiber-reinforced resins have been adopted to reduce the weight of automobiles, aircraft, etc. For example, fiber-reinforced plastics (FRP) materials are formed by heating and pressurizing prepregs in which reinforcing fibers are impregnated with resin. FRP materials are bonded to metal materials, for example, by epoxy adhesives (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-140091 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned prior art, there is a concern that the strength may be reduced due to bonding with an epoxy adhesive.

[0005] The present invention has been made in view of the above problems, and one of its exemplary objects is to provide a joined structure that is lightweight and has excellent rigidity. [Means for solving the problem]

[0006] A bonding method according to one embodiment of the present invention includes the steps of: placing a metal member having a first surface on which a first metal oxide particle cluster is formed and a second surface on which a second metal oxide particle cluster is formed, and having a thickness from the first surface to the second surface of 1 mm or less, between a first member containing a first thermoplastic resin and a second member containing a second thermoplastic resin; and heating and pressurizing the metal member between the first member and the second member to bond the first surface to the first resin and the second surface to the second resin.

[0007] Another aspect of the present invention is a bonded structure comprising a first member containing a first thermoplastic resin, a second member containing a second thermoplastic resin, and a metal member having a first surface on which first metal oxide particle clusters bonded to the first resin of the first member are formed, and a second surface on which second metal oxide particle clusters bonded to the second resin of the second member are formed, the thickness from the first surface to the second surface being 5 μm or more and 1 mm or less.

[0008] According to one embodiment of the present invention, a joint structure that is lightweight and has excellent rigidity can be provided. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view that shows a schematic configuration of a joint structure according to a first embodiment. [Diagram 2] 2(a) to (c) are diagrams illustrating the bonding method according to the first embodiment. [Diagram 3] FIG. 6 is a perspective view showing a schematic configuration of a joint structure according to a second embodiment. [Figure 4] FIG. 11 is a perspective view illustrating a schematic configuration of a reinforcing member according to a second embodiment. [Diagram 5] FIG. 11 is a perspective view illustrating a schematic configuration of a reinforcing member according to a second embodiment. [Figure 6] FIG. 11 is a top view illustrating a schematic configuration of a reinforcing member according to a second embodiment. [Figure 7] FIG. 11 is a side cross-sectional view that illustrates a schematic configuration of a reinforcing member according to a second embodiment. [Figure 8]FIG. 13 is a top view showing a schematic lattice frame shape at the top. [Figure 9] 9(a) and (b) are diagrams illustrating a method for forming a prepreg sheet. [Figure 10] 6A to 6C are diagrams illustrating a molding method for a reinforcing member according to a second embodiment. [Figure 11] 11(a) and (b) are diagrams showing the orientation direction of a prepreg sheet. [Figure 12] FIG. 4 is a top view showing a reinforcing member according to the embodiment. [Figure 13] FIG. 4 is a diagram illustrating a joint between a main body member and a reinforcing member. [Figure 14] FIG. 11 is a top view illustrating a schematic configuration of a metal member according to a second embodiment. [Figure 15] FIG. 13 is a perspective view showing a schematic configuration of a reinforcing member according to a modified example. [Figure 16] FIG. 13 is a perspective view showing a schematic configuration of a reinforcing member according to a modified example. [Figure 17] 10A to 10C are diagrams illustrating a molding method of a reinforcing member according to a modified example. [Figure 18] FIG. 11 is a side cross-sectional view that shows roughly the configuration of a joint structure according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. In the description, the same elements are given the same reference numerals, and duplicated descriptions will be omitted as appropriate. In order to facilitate understanding of the description, the dimensional ratios of the components in each drawing do not necessarily match the actual dimensional ratios.

[0011] (First embodiment) 1 is a cross-sectional view that shows a schematic configuration of a joint structure 200 according to the first embodiment. The joint structure 200 includes a first member 210, a second member 220, and a metal member 230. The joint structure 200 is a structure in which the first member 210 and the second member 220 are joined by the metal member 230, and the metal member 230 functions as an adhesive or bonding material.

[0012] The first member 210 includes a thermoplastic first resin. The first member 210 is a resin material entirely composed of the first resin, or a fiber-reinforced resin material including a first reinforcing fiber impregnated with the first resin. The second member 220 includes a thermoplastic second resin. The second member 220 is a resin material entirely composed of the second resin, or a fiber-reinforced resin material including a second reinforcing fiber impregnated with the second resin. The first resin and the second resin may be the same resin material or different resin materials. Similarly, the first reinforcing fiber and the second reinforcing fiber may be the same reinforcing fiber material or different reinforcing fiber materials. At least one of the first reinforcing fiber and the second reinforcing fiber can be provided so as to extend in a direction along the first surface 232 or the second surface 234 of the metal member 230. At least one of the first reinforcing fiber and the second reinforcing fiber may be knitted.

[0013] At least one of the first resin and the second resin is a thermoplastic engineering plastic, such as aromatic polyetherketone (PAEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyphenylene sulfide (PPS), polyetherimide (PEI), or polyethersulfone (PES). At least one of the first reinforcing fiber and the second reinforcing fiber is carbon fiber, glass fiber, or aramid fiber.

[0014] The metal member 230 has a first surface 232 that is bonded to the first member 210, and a second surface 234 that is bonded to the second member 220. The thickness of the metal member 230 from the first surface 232 to the second surface 234 is 5 μm or more and 2 mm or less, for example, 10 μm or more and 1 mm or less, for example, 50 μm or more and 0.5 mm or less. For example, a steel material, an aluminum material, an aluminum alloy material, a titanium material, a titanium alloy material, a nickel-titanium alloy material, a copper material, or a copper alloy material can be used as the metal member 230.

[0015] A first metal oxide particle cluster 236 for bonding with the first resin is formed on the first surface 232. A second metal oxide particle cluster 238 for bonding with the second resin is formed on the second surface 234. At least one of the first metal oxide particle cluster 236 and the second metal oxide particle cluster 238 can be formed by heating and modifying the surface of the metal member 230 by laser irradiation or the like. The metal oxide particle cluster is, for example, composed of an oxide of the metal material constituting the metal member 230 before heating. The metal oxide particle cluster is, for example, a metal material locally melted, and particulate metal oxide is fixed to the surface. The particle size of the metal oxide particle cluster is, for example, 5 nm or more and 500 nm or less, for example, 50 nm or more and 200 nm or less. The maximum height of the metal oxide particle cluster is, for example, 50 nm or more and 3 μm or less, for example, 100 nm or more and 2 μm or less, for example, 200 nm or more and 1 μm or less.

[0016] The first metal oxide particle cluster 236 chemically bonds with the first resin contained in the first member 210, and physically bonds with the first resin by the softened first resin penetrating the unevenness of the particle cluster. By providing the first metal oxide particle cluster 236, the bonding strength between the first member 210 and the metal member 230 can be improved. Similarly, the second metal oxide particle cluster 238 chemically bonds with the second resin contained in the second member 220, and physically bonds with the second resin by the softened second resin penetrating the unevenness of the particle cluster. By providing the second metal oxide particle cluster 238, the bonding strength between the second member 220 and the metal member 230 can be improved. By bonding the first member 210 and the second member 220 via the metal oxide particle cluster, the bonding strength can be dramatically improved compared to the case where the first resin and the second resin are directly bonded by fusing them together, or the case where they are bonded via an epoxy adhesive.

[0017] 2(a) to (c) are diagrams illustrating a bonding method according to the first embodiment. First, as shown in FIG. 2(a), a metal member 230 is disposed between a first member 210 and a second member 220. The metal member 230 includes a bonding portion 240, a first extending portion 242, and a second extending portion 244. The bonding portion 240 is a portion located between the first member 210 and the second member 220. A first metal oxide particle cluster 236 and a second metal oxide particle cluster 238 are formed on both sides of the bonding portion 240.

[0018] The first extension portion 242 and the second extension portion 244 are portions that extend and protrude from between the first member 210 and the second member 220. The first extension portion 242 is, for example, a portion that extends along the first member 210. The second extension portion 244 is, for example, a portion that extends along the second member 220. The first metal oxide particle cluster 236 and the second metal oxide particle cluster 238 may not be formed on both sides of the first extension portion 242 and the second extension portion 244. In the example shown in FIG. 2(a), a joint portion 240 is provided between the first extension portion 242 and the second extension portion 244. Note that the metal member 230 may include only one of the first extension portion 242 and the second extension portion 244, and not the other. The metal member 230 may include only the joint portion 240, without including the first extension portion 242 and the second extension portion 244.

[0019] Next, as shown in FIG. 2(b), the joint portion 240 of the metal member 230 is pressurized between the first member 210 and the second member 220 as indicated by the arrow F. The metal member 230 is heated while the metal member 230 is being pressurized. The metal member 230 can be heated by irradiating it with electromagnetic waves or passing an electric current. For example, at least one of the first extension portion 242 and the second extension portion 244 may be irradiated with electromagnetic waves such as laser light or infrared light. For example, a power source may be connected to the first extension portion 242 and the second extension portion 244, and an electric current may be passed through the metal member 230 to perform resistance heating. Alternatively, the metal member 230 may be heated by high-frequency induction heating, in which a high-frequency magnetic field is applied by arranging a coil around at least one of the first extension portion 242 and the second extension portion 244 to generate an eddy current in the metal member 230. By applying pressure while heating the metal member 230, the first resin of the first member 210 softens and bonds to the first metal oxide particle clusters 236, and the second resin of the second member 220 softens and bonds to the second metal oxide particle clusters 238.

[0020] Next, as shown in FIG. 2(c), the first extension portion 242 and the second extension portion 244 are cut off and removed from the joint portion 240 that is joined between the first member 210 and the second member 220. The first extension portion 242 and the second extension portion 244 are non-joint portions that are not joined to the first member 210 or the second member 220, and do not contribute to the joining. This completes the joined structure 200 shown in FIG. 1. Note that the first extension portion 242 and the second extension portion 244 do not need to be removed, and at least one of the first extension portion 242 and the second extension portion 244 may remain connected to the joint portion 240.

[0021] The metal member 230 may be preheated before being disposed between the first member 210 and the second member 220 .

[0022] According to this embodiment, the bonding strength between the first member 210 and the second member 220 can be improved. In addition, by making the thickness of the metal member 230 2 mm or less, preferably 1 mm or less, the increase in weight due to the addition of the metal member 230 can be suppressed. In addition, by making the thickness of the metal member 230 thin, even if the surface of the first member 210 or the second member 220 is curved, it becomes easy to make the film-like metal member 230 follow the surface of the first member 210 or the second member 220. In addition, when the first member 210 or the second member 220 contains knitted reinforcing fibers, it becomes easy to arrange the film-like metal member 230 along the fine unevenness caused by the knitting of the reinforcing fibers. As a result, it is possible to increase the adhesion between the first member 210 or the second member 220, which is a fiber-reinforced resin, and the metal member 230, and to improve the bonding strength.

[0023] Second embodiment FIG. 3 is a perspective view showing a schematic configuration of a joint structure 10 according to a second embodiment. The joint structure 10 is a blocker door attached to the outer periphery of an aircraft engine. The blocker door is a movable member for blocking the bypass airflow of the engine and causing reverse thrust. In the embodiment, a blocker door is shown as an example of the joint structure 10, but the use of the joint structure 10 according to this embodiment is not particularly limited. The joint structure 10 according to this embodiment can be applied to structural members of any shape and use.

[0024] The joint structure 10 includes a main body member 12 and a reinforcing member 14. The main body member 12 is a plate-like member and has a front surface 12a against which the bypass airflow hits during reverse injection, and a back surface 12b opposite to the front surface 12a. The main body member 12 has a gently curved shape overall. Since the main body member 12 is a thin plate-like member, it is prone to deformation (e.g., bending) due to a load applied to the front surface 12a. The reinforcing member 14 is attached to the back surface 12b of the main body member 12, and suppresses deformation (e.g., bending) of the front surface 12a of the main body member 12 and increases the rigidity of the main body member 12. The reinforcing member 14 is a plate-like member with projections and recesses formed thereon, and suppresses deformation (e.g., bending) due to the uneven shape.

[0025] Conventionally, sandwich panels having honeycomb cores have been used as lightweight and highly rigid structural members. The honeycomb core is expensive in itself, and is not easy to process into any shape, so that processing is costly. In this embodiment, the main body member 12 and the reinforcing member 14 are made of fiber reinforced plastics (FRP), and the reinforcing member 14 is joined to the main body member 12, thereby realizing a lightweight and highly rigid joined structure 10 without using a honeycomb core. The main body member 12 and the reinforcing member 14 are joined, for example, by a metal member (not shown in FIG. 3) having metal oxide particle clusters formed on the surface thereof, as in the first embodiment.

[0026] 4 to 7 are diagrams that show a schematic configuration of a reinforcing member 14 according to a second embodiment. The reinforcing member 14 is made of a plate-shaped member 16 on which projections and recesses are formed. The plate-shaped member 16 has a first surface 16a and a second surface 16b opposite to the first surface 16a. FIG. 4 is a perspective view of the first surface 16a, and FIG. 5 is a perspective view of the second surface 16b. FIG. 6 is a top view of the first surface 16a. FIG. 7 is a side cross-sectional view corresponding to the cross section taken along line VV in FIG. 6.

[0027] In the drawings, the thickness direction of the reinforcing member 14 is the z direction, the longitudinal direction of the reinforcing member 14 is the x direction, and the direction perpendicular to the x direction and the z direction is the y direction. These directions are set to facilitate understanding of the embodiment, and do not limit the directions during manufacture or use of the joined structure 10 or the reinforcing member 14. In the drawings, inflection portions of the uneven shape are also indicated with solid lines to clearly show the uneven shape.

[0028] The shape of the outer edge 18 of the plate-like member 16 is, for example, a quadrangle, for example, a rectangle. The outer edge 18 of the plate-like member 16 has a long side 18a extending in the longitudinal direction (for example, the x direction), a short side 18b extending in a direction intersecting the longitudinal direction (for example, the y direction), and a corner 18c provided between the long side 18a and the short side 18b. The shape of the outer edge 18 of the plate-like member 16 is not particularly limited, and may be a trapezoid, a rhombus, a parallelogram, or any polygon such as a triangle, a pentagon, or a hexagon. The corner 18c of the plate-like member 16 may be rounded off. The corner 18c may be rounded off in a straight line or in a circular arc.

[0029] The plate-like member 16 is configured to have a uniform thickness t (see FIG. 7) as a whole. The thickness t of the plate-like member 16 is not particularly limited, but is, for example, 0.5 mm or more and 10 mm or less, and preferably 1 mm or more and 5 mm or less.

[0030] The plate-like member 16 has an outer periphery 20, a protrusion 22, and a number of recesses 24.

[0031] The outer peripheral portion 20 is a portion that defines the outer edge 18 of the plate-like member 16. The outer peripheral portion 20 has a frame shape or a closed loop shape that follows the outer edge 18 of the plate-like member 16. The outer peripheral portion 20 is a portion that has less change in shape in the thickness direction compared to the protrusions 22 and the multiple recesses 24. The outer peripheral portion 20 is a portion that is joined to the back surface 12b of the main body member 12, and has a shape that follows the back surface 12b of the main body member 12. If the back surface 12b of the main body member 12 has a gently curved shape, the outer peripheral portion 20 has a gently curved shape as a whole. If the back surface 12b of the main body member 12 is flat, the outer peripheral portion 20 has a flat shape as a whole.

[0032] The protrusion 22 is formed inside the outer periphery 20. The protrusion 22 is formed in a region inside the region where the outer periphery 20 is formed in a plan view of the first surface 16a (see FIG. 6). The protrusion 22 is a portion that protrudes in the thickness direction relative to the outer periphery 20. The protrusion 22 protrudes toward the first surface 16a, and is formed so that the first surface 16a is convex and the second surface 16b is concave. The protrusion 22 is formed, for example, so as to occupy most of the plate-like member 16. The area S1 surrounded by the outer edge 26 of the protrusion 22 is 50% or more of the area S surrounded by the outer edge 18 of the plate-like member 16, and is preferably 70% or more or 80% or more.

[0033] The outer edge 26 of the protrusion 22 has a first section 26a extending in the longitudinal direction (e.g., x direction) along the long side 18a, a second section 26b extending in a direction intersecting the longitudinal direction (e.g., y direction) along the short side 18b, and a third section 26c extending in an arc shape between the first section 26a and the second section 26b. The radius of curvature of the third section 26c is larger than the radius of curvature of the corner 18c of the plate-like member 16. In the illustrated example, the outer edge 26 of the protrusion 22 has a shape in which the four corners of a rectangle are arc-shaped.

[0034] The apex 28 of the protrusion 22 is configured so that the height h1 (see FIG. 7) in the thickness direction from the outer periphery 20 is constant. When the outer periphery 20 is flat, the apex 28 is also configured so that it is flat. When the outer periphery 20 is gently curved, the apex 28 is also configured so that it is gently curved. The height h1 in the thickness direction from the outer periphery 20 to the apex 28 is preferably 50 mm or less, and more preferably 30 mm or less. The height h1 in the thickness direction from the outer periphery 20 to the apex 28 is preferably larger than the thickness t of the plate-like member 16, and is, for example, 5 mm or more, for example, 10 mm or more.

[0035] An outer inclined portion 30 (see FIG. 7) is provided between the outer periphery 20 and the apex 28. The outer inclined portion 30 is formed so that its height increases monotonically from the outer periphery 20 to the apex 28. The outer inclined portion 30 is preferably formed so that the inclination does not change suddenly from the outer periphery 20 to the apex 28, and is formed only by smoothly curved surfaces. The outer inclined portion 30 is configured by a smooth curve with a radius of curvature of, for example, 20 mm or more or 30 mm or more in a cross-sectional view perpendicular to the outer edge 18 of the plate-like member 16.

[0036] The recesses 24 are formed on the inner side of the protrusion 22. The recesses 24 are formed in an area inside the outer edge 26 of the protrusion 22 in a plan view of the first surface 16a (see FIG. 6). The recesses 24 are formed, for example, in an area inside the outer edge of the apex 28 in a plan view of the first surface 16a (see FIG. 6). The recesses 24 are formed to be recessed in the thickness direction with respect to the apex 28. The recesses 24 protrude toward the second surface 16b, and are formed so that the first surface 16a is recessed and the second surface 16b is protruding. The recesses 24 are arranged in a lattice pattern on the apex 28. The recesses 24 are arranged in the longitudinal direction (e.g., x direction) of the plate-like member 16 and in a direction intersecting the longitudinal direction (e.g., y direction). The recesses 24 may be arranged radially on the apex 28.

[0037] The outer edge 32 (see FIG. 6) of each of the plurality of recesses 24 has a first section 32a extending in the longitudinal direction (e.g., x direction) along the long side 18a, a second section 32b extending in a direction intersecting the longitudinal direction (e.g., y direction) along the short side 18b, and a third section 32c extending in an arc shape between the first section 32a and the second section 32b. The radius of curvature of the third section 32c is larger than the radius of curvature of the corner 18c of the plate-like member 16. In the illustrated example, the outer edge 32 of the recess 24 has a shape in which the four corners of a rectangle are arc-shaped. The outer edge 32 of each of the plurality of recesses 24 has a size in the longitudinal direction (e.g., x direction) and a size in a direction intersecting the longitudinal direction (e.g., y direction) that are approximately the same. That is, the length of the first section 32a is approximately the same as the length of the second section 32b, for example, approximately 0.8 to 1.2 times the length of the second section 32b.

[0038] The bottoms 34 of the recesses 24 are portions that are joined to the back surface 12b of the main body member 12. The bottoms 34 are configured so that the depth h2 (see FIG. 7) in the thickness direction from the top 28 is constant. When the outer peripheral portion 20 is flat, the bottoms 34 of the recesses 24 are configured to be located on a virtual plane B (see FIG. 7) defined by the outer peripheral portion 20. When the outer peripheral portion 20 is gently curved, the bottoms 34 of the recesses 24 are configured to be located on a curved surface defined by the outer peripheral portion 20. The height h2 in the thickness direction from the top 28 to the bottom 34 is preferably 50 mm or less, and more preferably 30 mm or less. The height h2 in the thickness direction from the top 28 to the bottom 34 is, for example, 5 mm or more, for example, 10 mm or more.

[0039] The bottom 34 of each of the multiple recesses 24 has a rectangular shape or a rectangular shape with rounded corners. By making the bottom 34 a rectangular shape or a shape close to a rectangular shape, the area occupied by the bottom 34 can be increased compared to when the bottom 34 is a circular shape. This makes it possible to increase the bonding area between the main body member 12 and the top 28, and to increase the bonding strength between the main body member 12 and the reinforcing member 14.

[0040] An inner inclined portion 36 (see FIG. 7) is provided between the top 28 and the bottom 34. The inner inclined portion 36 is formed so that its height increases monotonically from the bottom 34 to the top 28. The inner inclined portion 36 is preferably formed so that the slope does not change suddenly from the bottom 34 to the top 28, and is formed only by smoothly curved surfaces. The inner inclined portion 36 is configured by a smooth curve with a radius of curvature of, for example, 20 mm or more or 30 mm or more in a cross-sectional view perpendicular to the outer edge 18 of the plate-like member 16.

[0041] The top 28 has a lattice frame shape surrounding the outer edges 32 of the multiple recesses 24 by arranging the multiple recesses 24 in a lattice shape. FIG. 8 is a top view showing the lattice frame shape of the top 28, and the lattice frame shape of the top 28 is shown by thick lines. The top 28 includes multiple first beams 38a, 38b extending in the longitudinal direction (e.g., x direction), multiple second beams 40a, 40b extending in a direction intersecting the longitudinal direction (e.g., y direction), and multiple corners 42 extending in an arc shape. The multiple first beams 38a, 38b include an outer first beam 38a located outside the multiple recesses 24 and an inner first beam 38b located between the multiple recesses 24. The multiple second beams 40a, 40b include an outer second beam 40a located outside the multiple recesses 24 and an inner second beam 40b located between the multiple recesses 24. The outer first beam 38a and the outer second beam 40a are connected by corners 42 extending in an arc shape. Both ends of the inner first beam 38b are connected to the outer second beam 40a. Both ends of the inner second beam 40b are connected to the outer first beam 38a. The top 28 has a lattice frame shape formed by the first beams 38a, 38b, the second beams 40a, 40b and the corners 42, and is therefore capable of responding to load changes in both the longitudinal direction (e.g., the x direction) and the direction intersecting the longitudinal direction (e.g., the y direction).

[0042] The reinforcing member 14 is made of a fiber-reinforced resin, for example, a thermoplastic fiber-reinforced resin. The reinforcing member 14 is formed by heating and pressurizing a prepreg sheet formed by impregnating reinforcing fibers with a resin in a mold to form a shape. Carbon fiber, glass fiber, or aramid fiber can be used as the reinforcing fiber. The reinforcing fiber is preferably a continuous fiber without a joint or a cut, and it is preferable to use a reinforcing fiber that extends continuously along the uneven shape of the plate-like member 16. Engineering plastics such as polyether ether ketone (PEEK) and polyether ketone ketone (PEKK) can be used as the thermoplastic resin to be impregnated into the reinforcing fiber. The main body member 12 can also be made of a fiber-reinforced resin similar to that of the reinforcing member 14, and can be made of a thermoplastic fiber-reinforced resin similar to that of the reinforcing member 14. The main body member 12 or the reinforcing member 14 may be made of a thermosetting fiber-reinforced resin. In this case, an epoxy resin or the like can be used as the thermosetting resin to be impregnated into the reinforcing fiber.

[0043] 9(a) and (b) are diagrams showing a schematic diagram of a method for forming a prepreg sheet. FIG. 9(a) shows a prepreg tape 50 used for forming the prepreg sheet. The prepreg tape 50 is obtained by impregnating a plurality of reinforcing fibers 52 oriented in a single direction with a thermoplastic resin 54. The plurality of reinforcing fibers 52 are oriented so as to extend in the longitudinal direction A of the prepreg tape 50. The thermoplastic resin 54 fills the gaps between the plurality of reinforcing fibers 52, and fixes the fiber bundles composed of the plurality of reinforcing fibers 52 so that the relative positions of the plurality of reinforcing fibers 52 do not change. The width w of the prepreg tape 50 is not particularly limited, but is, for example, 1 mm or more and 20 mm or less, for example, 2 mm or more and 10 mm or less. The length L of the prepreg tape 50 is larger than the outer size of the reinforcing member 14, and is, for example, 0.5 m or more or 1 m or more. The thickness of the prepreg tape 50 is, for example, not less than 0.1 mm and not more than 2 mm, for example, not less than 0.2 mm and not more than 1 mm.

[0044] FIG. 9(b) shows a prepreg sheet 60 formed using the prepreg tape 50. The prepreg sheet 60 is formed by knitting a plurality of first prepreg tapes 56 extending in a first direction A1 and a plurality of second prepreg tapes 58 extending in a second direction A2 intersecting the first direction A1. Each of the first prepreg tape 56 and the second prepreg tape 58 is configured in the same manner as the prepreg tape 50 shown in FIG. 9(a). In the prepreg sheet 60 shown in FIG. 9(b), the first direction A1 and the second direction A2 are perpendicular to each other. In other words, if the first direction A1 is set to a 0 degree direction, the second direction A2 is set to a 90 degree direction.

[0045] There is a first gap d1 between the multiple first prepreg tapes 56. The first gap d1 is smaller than the width w1 of the first prepreg tape 56. The first gap d1 is, for example, 1% to 50% of the width w1 of the first prepreg tape 56, and preferably 5% to 25%. Similarly, there is a second gap d2 between the multiple second prepreg tapes 58. The second gap d2 is smaller than the width w2 of the second prepreg tape 58. The second gap d2 is, for example, 1% to 50% of the width w2 of the second prepreg tape 58, and preferably 5% to 25%. The width w1 of the first prepreg tape 56 may be the same as or different from the width w2 of the second prepreg tape 58. The first gap d1 may be the same as or different from the second gap d2.

[0046] In the prepreg sheet 60, the first prepreg tapes 56 and the second prepreg tapes 58 that intersect with each other are not fixed. Therefore, the first prepreg tapes 56 are displaceable relative to each other in the second direction A2, and the first gap d1 is variable. Similarly, the second prepreg tapes 58 are displaceable relative to each other in the first direction A1, and the second gap d2 is variable.

[0047] The resin weight content (wt%) of the prepreg sheet 60 is 50% or less, for example, 40% or less, 35% or less, 30% or less, or 25% or less. By reducing the resin weight content of the prepreg sheet 60, the rigidity of the reinforcing member 14 can be increased. The resin weight content (wt%) of the prepreg tape 50 forming the prepreg sheet 60 may be the same as the resin weight content of the prepreg sheet 60, and is 50% or less, for example, 40% or less, 35% or less, 30% or less, or 25% or less.

[0048] In the prepreg sheet 60 shown in Fig. 9(b), a first prepreg tape 56 and a second prepreg tape 58 are woven to form a twill weave. The weaving method of the prepreg sheet is not limited to twill weave, and the prepreg sheet may be formed using any other weaving method such as plain weave or satin weave. The prepreg sheet may be woven using prepreg tapes extending in three or more directions, and may be woven using, for example, a plurality of first prepreg tapes extending in a first direction (e.g., 0 degree direction), a plurality of second prepreg tapes extending in a second direction (e.g., +60 degree direction) intersecting the first direction, and a plurality of third prepreg tapes extending in a third direction (e.g., -60 degree direction) intersecting the first direction and the second direction.

[0049] The prepreg sheet may be formed without using a prepreg tape in which unidirectional fibers are impregnated with a resin. The prepreg sheet may be formed, for example, by impregnating a continuous fiber sheet, which is formed by using continuous fibers, entirely with a thermoplastic resin. For example, a continuous fiber sheet may be formed by weaving a plurality of first continuous fibers extending in a first direction (e.g., 0 degree direction) and a plurality of second continuous fibers extending in a second direction (e.g., 90 degree direction) intersecting the first direction in a plain weave, twill weave, satin weave, or the like. The prepreg sheet may be formed by impregnating such a continuous fiber sheet with a thermoplastic resin. In this case, the first continuous fibers and the second continuous fibers intersecting with each other in the prepreg sheet are fixed with a resin between them.

[0050] 10 is a diagram showing a schematic diagram of a molding method of the reinforcing member 14 according to the second embodiment. A mold 62 for molding the reinforcing member 14 is prepared, and a plurality of prepreg sheets 60a, 60b, 60c are stacked and arranged between an upper mold 64 and a lower mold 66 of the mold 62. The upper mold 64 has a concave-convex shape corresponding to the first surface 16a of the plate-like member 16, and the lower mold 66 has a concave-convex shape corresponding to the second surface 16b of the plate-like member 16. The upper mold 64 and the lower mold 66 may be used upside down regardless of the up-down relationship.

[0051] Each of the multiple prepreg sheets 60a to 60c is configured similarly to the prepreg sheet 60 shown in FIG. 9(b). The multiple prepreg sheets 60a to 60c include a first prepreg sheet 60a, a second prepreg sheet 60b, and an intermediate prepreg sheet 60c. The first prepreg sheet 60a is a sheet that contacts the upper mold 64 and constitutes the first surface 16a of the plate-like member 16. The second prepreg sheet 60b is a sheet that contacts the lower mold 66 and constitutes the second surface 16b of the plate-like member 16. The intermediate prepreg sheet 60c is disposed between the first prepreg sheet 60a and the second prepreg sheet 60b. In the example of FIG. 10, five prepreg sheets are laminated, including one first prepreg sheet 60a, one second prepreg sheet 60b, and three intermediate prepreg sheets 60c. The number of laminated prepreg sheets is not particularly limited and may be 4 or less, or may be 6 or less. The number of laminated prepreg sheets can be appropriately set depending on the thickness of the prepreg sheets and the thickness t of the reinforcing member 14 to be molded.

[0052] The multiple prepreg sheets 60a to 60c may be arranged such that the orientation directions of the prepreg tapes constituting the prepreg sheets 60a to 60c are different from each other. FIGS. 11(a) and 11(b) are diagrams that typically show the orientation directions of the prepreg sheets 60a to 60c. FIG. 11(a) shows the orientation directions of the first prepreg sheet 60a and the second prepreg sheet 60b. In the first prepreg sheet 60a and the second prepreg sheet 60b, the orientation directions A1 and A2 of the first prepreg tape 56 and the second prepreg tape 58 are oriented at 45 degrees with respect to the longitudinal direction (e.g., the x direction) of the reinforcing member 14. FIG. 11(b) shows the orientation direction of the intermediate prepreg sheet 60c. In the intermediate prepreg sheet 60c, the orientation direction A1 of the first prepreg tape 56 coincides with the longitudinal direction (e.g., the x direction) of the reinforcing member 14. Therefore, the orientation directions A1, A2 of the intermediate prepreg sheet 60c are rotated by 45 degrees with respect to the orientation directions A1, A2 of the first prepreg sheet 60a and the second prepreg sheet 60b.

[0053] The plate-like member 16 can be formed by heating and pressurizing the multiple prepreg sheets 60a to 60c between an upper mold 64 and a lower mold 66 shown in FIG. 10. The multiple prepreg sheets 60a to 60c in FIG. 10 are heated to a temperature equal to or higher than the melting point of the thermoplastic resin 54 by the upper mold 64 and the lower mold 66 equipped with heaters. The multiple prepreg sheets 60a to 60c are integrated by heating and pressurizing by a mold 62, and are shaped into the plate-like member 16. Thereafter, the plate-like member 16 is removed from the mold 62, thereby completing the plate-like member 16. After shaping by the mold 62, a portion unnecessary for the reinforcing member 14 may be cut from the plate-like member 16, or the first surface 16a or the second surface 16b of the plate-like member 16 may be polished.

[0054] FIG. 12 is a top view showing a reinforcing member 14 according to an embodiment. The reinforcing member 14 shown in FIG. 12 uses carbon fiber as reinforcing fiber, PEEK as thermoplastic resin, and prepreg sheets 60a, 60b, and 60c shown in FIG. 11(a) and (b). As shown in FIG. 12, it can be seen that a plate-like member 16 having a complex uneven shape including a protrusion 22 and a plurality of recesses 24 can be formed. In particular, since there is almost no misalignment of the stitches of the prepreg tape extending in the ±45 degree direction throughout the plate-like member 16, the reinforcing member 14 can have high rigidity throughout the plate-like member 16. It can also be seen that the bottoms 34 of the plurality of recesses 24 have a shape close to a rectangle.

[0055] FIG. 13 is a diagram showing a joint 44 between the main body member 12 and the reinforcing member 14. The reinforcing member 14 is joined to the back surface 12b of the main body member 12. The reinforcing member 14 is joined to the main body member 12 by a plurality of joints 44. The plurality of joints 44 are provided between the back surface 12b of the main body member 12 and the second surface 16b of the reinforcing member 14. The plurality of joints 44 are provided on the outer periphery 20 and the bottom 34 of the reinforcing member 14. A cavity 48 is provided between the main body member 12 and the reinforcing member 14. The main body member 12, the reinforcing member 14, and the plurality of joints 44 correspond to the first member 210, the second member 220, and the metal member 230 according to the first embodiment.

[0056] Each of the multiple joints 44 can be configured in the same manner as the metal member 230 according to the first embodiment. The multiple joints 44 have a first surface that is joined to the main body member 12 and a second surface that is joined to the reinforcing member 14, and a metal material is formed between the first surface and the second surface, and metal oxide particle clusters are formed on the first surface and the second surface. The metal oxide particle clusters of the multiple joints 44 are chemically and physically bonded to the thermoplastic resin contained in the main body member 12 or the reinforcing member 14. The multiple joints 44 can be formed, for example, by disposing a metal member between the main body member 12 and the reinforcing member 14, and applying heat and pressure to the metal member between the main body member 12 and the reinforcing member 14.

[0057] 14 is a top view illustrating a schematic configuration of a metal member 250 according to the second embodiment. The metal member 250 includes an outer periphery bonding portion 252, an inner bonding portion 254, an extension portion 256, a first connection portion 258, and a second connection portion 260.

[0058] The outer peripheral joining portion 252 is a portion that joins with the outer peripheral portion 20 of the reinforcing member 14. The outer peripheral joining portion 252 can have a shape similar to that of the outer peripheral portion 20 of the reinforcing member 14. The inner joining portion 254 is a portion that joins with the bottom 34 of the recess 24 of the reinforcing member 14.

[0059] The extending portion 256 is a portion that extends outward from the outer edge 18 of the reinforcing member 14, and is a non-joint portion that is not joined to the reinforcing member 14. In the example of Fig. 14, the extending portion 256 is provided so as to extend in the y direction, but the extending direction of the extending portion 256 is not important, and it may extend in the x direction or obliquely with respect to the x direction or the y direction.

[0060] The first connection portion 258 is a portion that connects between the outer peripheral joint portion 252 and the inner joint portion 254, and is a non-joint portion that is not joined to the reinforcing member 14. The second connection portion 260 is a portion that connects between two adjacent inner joint portions 254, and is a non-joint portion that is not joined to the reinforcing member 14. In the example of FIG. 14, the first connection portion 258 and the second connection portion 260 extend in the y direction, but the direction in which the first connection portion 258 and the second connection portion 260 extend is not important, and they may extend in the x direction or obliquely to the x direction or y direction. The metal member 250 may include two or more of a connection member that extends in the x direction, a connection member that extends in the y direction, and a connection member that extends obliquely to the x direction or y direction.

[0061] Metal oxide particle clusters are formed on both sides of the outer peripheral joint portion 252 and the inner joint portion 254. On the other hand, metal oxide particle clusters may not be formed on both sides of the extension portion 256, the first connection portion 258, and the second connection portion 260. The metal member 250 may not include at least one of the extension portion 256, the first connection portion 258, and the second connection portion 260. For example, the metal member 250 may include the first connection portion 258 but not the second connection portion 260. The metal member 250 may not include the extension portion 256 but may include at least one of the first connection portion 258 and the second connection portion 260.

[0062] The metal member 250 can be made of the same material as the metal member 230 according to the first embodiment described above. The thickness of the metal member 250 can be the same as the thickness of the metal member 230 according to the first embodiment, and can be, for example, 5 μm to 2 mm, for example, 10 μm to 1 mm, for example, 50 μm to 0.5 mm.

[0063] Next, a method for joining the main body member 12 and the reinforcing member 14 using the metal member 250 will be described. First, the metal member 250 is placed between the main body member 12 and the reinforcing member 14. Next, the metal member 250 is pressed between the main body member 12 and the reinforcing member 14. For example, by pressing the main body member 12 and the reinforcing member 14 using a mold corresponding to the shapes of the main body member 12 and the reinforcing member 14, the outer periphery 20 and the bottom 34, which are the joining points of the reinforcing member 14, can be effectively pressed.

[0064] Next, the metal member 250 is heated while being pressurized between the main body member 12 and the reinforcing member 14. For example, the metal member 250 can be heated by utilizing the extension portion 256 protruding from between the main body member 12 and the reinforcing member 14. The extension portion 256 may be heated by irradiating it with electromagnetic waves such as laser light or infrared light. The extension portion 256 may be connected to a power source for resistance heating. The extension portion 256 may be inductively heated by applying a magnetic field to it. By heating the metal member 250 while pressurizing it, the softened resin penetrates into the metal oxide particle clusters of the metal member 250 and the resin is chemically bonded. As a result, the main body member 12 and the reinforcing member 14 are firmly joined via the metal member 250.

[0065] When the metal member 250 does not include the extension portion 256, the outer circumferential bonding portion 252 and the inner bonding portion 254 may be directly heated. For example, the outer circumferential bonding portion 252 and the inner bonding portion 254 may be high-frequency induction heated by applying a magnetic field from the outside of the main body member 12 and the reinforcing member 14. In this case, the first connecting portion 258 and the second connecting portion 260 may be high-frequency induction heated, and the inner bonding portion 254 may be heated by heat transferred from the first connecting portion 258 and the second connecting portion 260.

[0066] After the main body member 12 and the reinforcing member 14 are joined, the extension portion 256 that protrudes outside the reinforcing member 14 can be cut and removed. The extension portion 256 does not have to be removed. Meanwhile, the first connection portion 258 and the second connection portion 260 remain between the main body member 12 and the reinforcing member 14. The first connection portion 258 and the second connection portion 260 may or may not be joined to the main body member 12 or the reinforcing member 14.

[0067] According to this embodiment, the reinforcing member 14 can be constructed of only a single plate-like member 16, so that the structure of the reinforcing member 14 can be simplified compared to when a honeycomb core is used. In addition, the reinforcing member 14 can be formed by a molded molding using a die 62, so that the manufacturing process of the reinforcing member 14 can be simplified compared to when a honeycomb core is used. The reinforcing member 14 has a lattice frame-shaped top portion 28 having beams extending in the longitudinal direction (e.g., x direction) and in a direction intersecting the longitudinal direction (e.g., y direction) of the reinforcing member 14, so that the reinforcing member 14 can withstand loads in both the longitudinal direction and the direction intersecting the longitudinal direction. As a result, the reinforcing member 14 can suitably suppress deformation of the main body member 12.

[0068] According to this embodiment, the reinforcing member 14 can be formed from continuous reinforcing fibers throughout the entire reinforcing member 14, which improves the rigidity of the reinforcing member 14 compared to a case in which a notch is provided midway through the reinforcing fibers. According to this embodiment, the outer inclined portion 30 and the inner inclined portion 36 are configured to be gently curved, which makes it possible to suppress misalignment of the stitches of the prepreg tape made of continuous fibers, thereby improving the overall rigidity of the reinforcing member 14.

[0069] According to this embodiment, by joining the main body member 12 and the reinforcing member 14 via the metal member 250, it is possible to dramatically improve the joining strength compared to a case where the metal member 250 is not used. In addition, by using the metal member 250 with a small thickness, it is possible to suppress an increase in weight due to the addition of the metal member 250. As a result, it is possible to provide a joined structure 10 that is lightweight and has excellent rigidity.

[0070] According to this embodiment, the metal member 250 includes the first connecting portion 258 and the second connecting portion 260, so that the inner joint portion 254 can be heated through the connecting portion. For example, when the main body member 12 and the reinforcing member 14 are made of carbon fiber reinforced plastics (CFRP), it is difficult to heat the inner joint portion 254 between the main body member 12 and the reinforcing member 14 by irradiating electromagnetic waves from the outside because the carbon fibers are black. In addition, since the carbon fibers are conductive, when a magnetic field is applied from the outside to perform induction heating, the carbon fibers are heated, and the inner joint portion 254 may not be heated sufficiently. When the metal member 250 is heated from the outside, the outer surface side of the main body member 12 or the reinforcing member 14 is heated to a high temperature, and the main body member 12 or the reinforcing member 14 may be deformed. According to this embodiment, the inner joint portion 254 can be sufficiently heated through the connecting portion, and the joint strength between the main body member 12 and the reinforcing member 14 at the inner joint portion 254 can be improved, and a joint structure 10 with superior rigidity can be provided.

[0071] According to this embodiment, by making the first connection portion 258 and the second connection portion 260 non-joint portions, it is possible to prevent the main body member 12 or the reinforcing member 14 from contacting the connection portions. This makes it possible to suppress softening and deformation of the surfaces of the main body member 12 and the reinforcing member 14 in places where joining is not required. Furthermore, by providing the first connection portion 258 and the second connection portion 260, it is possible to appropriately position the inner joint portion 254 at the joint portion. In particular, by providing a connection portion that is not joined to the main body member 12 or the reinforcing member 14, it is possible to more appropriately position the inner joint portion 254 at the joint portion.

[0072] 15 is a perspective view showing a schematic configuration of a reinforcing member 70 according to a modified example, showing the reinforcing member 70 as viewed from the first surface 16a. The reinforcing member 70 differs from the above-described embodiment in that it further includes a first rib 72 provided on the first surface 16a of the plate-shaped member 16. The plate-shaped member 16 is configured in the same manner as in the above-described embodiment.

[0073] The reinforcing member 70 includes a plate-shaped member 16 and a first rib 72. The first rib 72 is provided on a first surface 16a of the plate-shaped member 16 and extends from the first surface 16a in the thickness direction. The first rib 72 is provided on the inside of at least one of the multiple recesses 24. In the example of FIG. 15, the first rib 72 is provided on the inside of the recess 24 at the center in the longitudinal direction (e.g., the x direction). The first rib 72 can be provided on the inside of any two or more of the multiple recesses 24, and can also be provided on the inside of all of the multiple recesses 24. The upper surface of the first rib 72 is configured to be flush with the top 28, for example.

[0074] The first rib 72 includes a first horizontal rib 74 extending in a longitudinal direction (e.g., x direction) and a first vertical rib 76 extending in a direction intersecting the longitudinal direction (e.g., y direction). Both ends of the first horizontal rib 74 are connected to the outer edge 32 of the recess 24. Both ends of the first vertical rib 76 are connected to the outer edge 32 of the recess 24. The first horizontal rib 74 and the first vertical rib 76 are intersecting and connected at the position of the bottom 34 of the recess 24. The first rib 72 may further include a first diagonal rib (not shown) extending in a diagonal direction (e.g., ±45 degrees) relative to the first horizontal rib 74 or the first vertical rib 76. The first rib 72 may include any one or more selected from the group including the first horizontal rib 74, the first vertical rib 76, and the first diagonal rib.

[0075] 16 is a perspective view showing a schematic configuration of a reinforcing member 70 according to a modified example, showing the reinforcing member 70 as viewed from the second surface 16b. The reinforcing member 70 further includes a second rib 82 provided on the second surface 16b of the plate-shaped member 16. The lower surface of the second rib 82 is configured to be flush with the outer circumferential portion 20 and the bottoms 34 of the multiple recesses 24. The lower surface of the second rib 82 is configured to be located on, for example, imaginary plane B shown in FIG.

[0076] The second rib 82 is provided on the second surface 16b of the plate-like member 16, and extends in the thickness direction from the second surface 16b. The second rib 82 is provided on the inside of the protrusion 22. The second rib 82 includes second horizontal ribs 84a, 84b extending in the longitudinal direction (e.g., the x direction), second vertical ribs 86a, 86b extending in a direction intersecting the longitudinal direction (e.g., the y direction), and second diagonal ribs 88a, 88b extending in a diagonal direction (e.g., a ±45 degree direction).

[0077] The second horizontal ribs 84a, 84b include a second outer horizontal rib 84a connecting between the outer periphery 20 and the bottom 34, and a second inner horizontal rib 84b connecting between the two bottoms 34. The second longitudinal ribs 86a, 86b include a second outer vertical rib 86a connecting between the outer periphery 20 and the bottom 34, and a second inner vertical rib 86b connecting between the two bottoms 34. The second diagonal ribs 88a, 88b include a second outer diagonal rib 88a connecting between the outer periphery 20 and the bottom 34, and a second inner diagonal rib 88b connecting between the two bottoms 34. The second rib 82 may include any one or more selected from the group including the second outer horizontal rib 84a, the second inner horizontal rib 84b, the second longitudinal rib 86a, the second inner longitudinal rib 86b, the second outer diagonal rib 88a, and the second inner diagonal rib 88b.

[0078] The first rib 72 and the second rib 82 are made of fiber reinforced resin. The first rib 72 and the second rib 82 may be made of the same thermoplastic fiber reinforced resin or thermosetting fiber reinforced resin as the plate-shaped member 16, or may be made of a thermoplastic fiber reinforced resin or thermosetting fiber reinforced resin of a material different from the plate-shaped member 16. Carbon fiber, glass fiber, or aramid fiber can be used as the reinforcing fiber that constitutes the first rib 72 and the second rib 82. Engineering plastics such as thermoplastic resins such as PEEK and PEKK, and thermosetting resins such as epoxy resin can be used as the resin that constitutes the first rib 72 and the second rib 82. The first rib 72 and the second rib 82 may be made of reinforcing fibers that are not continuous with the reinforcing fibers that constitute the plate-shaped member 16, for example.

[0079] 17 is a diagram showing a schematic diagram of a molding method of a reinforcing member 70 according to a modified example. A mold 92 for molding the reinforcing member 70 according to the modified example differs from the mold 62 according to the above-described embodiment in that it includes grooves 98, 100 for molding the first rib 72 and the second rib 82. The upper mold 94 has a concave-convex shape corresponding to the first surface 16a of the plate-like member 16, and includes a first groove 98 for forming the first rib 72. The lower mold 96 has a concave-convex shape corresponding to the second surface 16b of the plate-like member 16, and includes a second groove 100 for forming the second rib 82.

[0080] The first groove 98 is filled with prepreg 90a, and the second groove 100 is filled with prepreg 90b. The prepregs 90a and 90b filled in the grooves 98 and 100 are, for example, chopped materials obtained by cutting the prepreg tape 50 or the prepreg sheet 60. There is no particular limit to the size (width and length) of the prepregs 90a and 90b. The width of the prepregs 90a and 90b is 1 mm or more and 20 mm or less, for example, 2 mm or more and 10 mm or less. The length of the prepregs 90a and 90b is 5 mm or more and 50 mm or less, for example, 10 mm or more and 30 mm or less.

[0081] A plurality of prepreg sheets 60a, 60b, and 60c are stacked and disposed between an upper mold 94 in which a first groove 98 is filled with prepreg 90a and a lower mold 96 in which a second groove 100 is filled with prepreg 90b. The plurality of prepreg sheets 60a, 60b, and 60c are similar to those in the above-described embodiment.

[0082] 17, the multiple prepreg sheets 60a-60c and the prepregs 90a, 90b are heated and pressurized between an upper mold 94 and a lower mold 96, whereby a reinforcing member 70 having a first rib 72 and a second rib 82 formed on a plate-like member 16 can be molded. The multiple prepreg sheets 60a-60c and the prepregs 90a, 90b are heated to a temperature equal to or higher than the melting point of the thermoplastic resin 54 by the upper mold 94 and the lower mold 96, which are equipped with heaters. The multiple prepreg sheets 60a-60c and the prepregs 90a, 90b are integrated by heating and pressurizing using a mold 92, and are formed into the reinforcing member 70. The mold 92 is then removed to complete the reinforcing member 70.

[0083] According to this modification, the first rib 72 is formed on the first surface 16a of the plate-shaped member 16, and the second rib 82 is formed on the second surface 16b of the plate-shaped member 16, so that the rigidity of the reinforcing member 70 can be further improved.

[0084] The reinforcing member 70 according to this modification can be used by being joined to the main body member 12. For example, in addition to the outer periphery 20 and the bottom 34 of the reinforcing member 70, the lower surface of the second rib 82 can be joined to the back surface 12b of the main body member 12. The reinforcing member 70 can be joined to the main body member 12 in the same manner as in the above-described embodiment. The metal member 250 can further include an inner joining portion that is joined to the second rib 82. The joined structure 10 can include the main body member 12, the reinforcing member 70 according to this modification, and the metal member 250.

[0085] In further variations, the reinforcing member 70 may include only one of the first rib 72 and the second rib 82. The reinforcing member 70 may include only the first rib 72 and not the second rib 82. The reinforcing member 70 may include only the second rib 82 and not the first rib 72.

[0086] Third embodiment 18 is a side cross-sectional view that shows a schematic configuration of a joint structure 110 according to a third embodiment. The joint structure 110 according to this embodiment has a so-called sandwich panel structure. The joint structure 110 includes a first main body member 112, a second main body member 114, a first reinforcing member 116, and a second reinforcing member 118.

[0087] The first body member 112 and the second body member 114 are members that correspond to the skins of the sandwich panel. Each of the first body member 112 and the second body member 114 can be configured similarly to the body member 12 according to the above-mentioned embodiment. The first reinforcing member 116 and the second reinforcing member 118 are members that correspond to the core of the sandwich panel. Each of the first reinforcing member 116 and the second reinforcing member 118 can be configured similarly to the reinforcing member 14 according to the above-mentioned embodiment or the reinforcing member 70 according to the modified example.

[0088] The first reinforcing member 116 includes a first perimeter 120, a first top portion 122, and a plurality of first bottom portions 124. The first reinforcing member 116 is joined to the first body member 112 via a plurality of first joint portions 126. The first body member 112 is joined to the first perimeter 120 and the plurality of first bottom portions 124 via the plurality of first joint portions 126. A first cavity 128 is provided between the first body member 112 and the first reinforcing member 116.

[0089] The second reinforcing member 118 includes a second perimeter 130, a second top portion 132, and a plurality of second bottom portions 134. The second reinforcing member 118 is joined to the second body member 114 via a plurality of second joint portions 136. The second body member 114 is joined to the second perimeter 130 and the plurality of second bottom portions 134 via a plurality of second joint portions 136. A second cavity 138 is provided between the second body member 114 and the second reinforcing member 118.

[0090] The first reinforcing member 116 is joined to the second reinforcing member 118 via a third joint 140. The third joint 140 is provided between the first apex 122 and the second apex 132. A third cavity 142 is provided between the first reinforcing member 116 and the second reinforcing member 118.

[0091] Each of the first bonding portion 126, the second bonding portion 136 and the third bonding portion 140 can be configured in the same manner as the bonding portion 44 according to the second embodiment described above. For example, a first metal member, a second metal member and a third metal member having metal oxide particle clusters formed on both sides are prepared, and the first main body member 112 and the first reinforcing member 116 are bonded together with the first metal member, the second main body member 114 and the second reinforcing member 118 are bonded together with the second metal member, and the first reinforcing member 116 and the second reinforcing member 118 are bonded together with the third metal member.

[0092] According to this embodiment, a sandwich panel structure can be realized by combining four plate-like members. According to this embodiment, the structure of the joint structure 110 can be simplified compared to the case where a honeycomb core is used, and the manufacturing process of the joint structure 110 can be simplified.

[0093] The present invention has been described above based on the embodiments. It will be understood by those skilled in the art that the present invention is not limited to the above-described embodiments, that various design changes are possible, that various modifications are possible, and that such modifications are also within the scope of the present invention.

[0094] Several aspects of the present invention will now be described.

[0095] A first aspect of the present invention is a reinforcing member comprising a plate-shaped member made of a fiber-reinforced resin using continuous fibers as reinforcing fibers and having a first surface and a second surface, the plate-shaped member comprising an outer periphery defining an outer edge of the plate-shaped member, a convex portion inside the outer periphery that is convex on the first surface side, and a plurality of concave portions inside the convex portions that are concave on the first surface side. According to the first aspect, by providing a convex portion on the inside of the outer periphery and a convex portion on the inside of the convex portion to form an uneven structure, deformation such as bending can be suitably suppressed against loads in both the longitudinal direction of the reinforcing member and the direction crossing the longitudinal direction. In addition, by providing a structure with convexities and concaves on the plate-shaped member, the plate-shaped member can be formed of a fiber-reinforced resin using continuous fibers as reinforcing fibers, and a reinforcing member that is lightweight and has high rigidity can be realized.

[0096] A second aspect of the present invention is the reinforcing member according to the first aspect, wherein the recesses are arranged in a lattice or radial pattern. According to the second aspect, by arranging the recesses in a lattice or radial pattern, deformation due to a load in the direction in which the recesses are arranged can be suitably suppressed.

[0097] A third aspect of the present invention is the reinforcing member according to the first or second aspect, in which the outer edge of the convex portion has a shape in which the four corners of a rectangle are arc-shaped, and the outer edge of each of the plurality of recesses has a shape in which the four corners of a rectangle are arc-shaped. According to the third aspect, by approximating the outer edges of the convex portion and each of the plurality of recesses to a rectangle, deformation due to a load in a direction along the sides of the rectangle can be suitably suppressed. In addition, by making the four corners of the outer edges of the convex portion and each of the plurality of recesses into an arc shape, it becomes easy to uniformly arrange continuous fibers along the surfaces of the convex portion and each of the plurality of recesses, and the rigidity of the reinforcing member as a whole can be improved.

[0098] A fourth aspect of the present invention is the reinforcing member according to the third aspect, wherein the bottom of each of the plurality of recesses has a rectangular shape or a rectangular shape with rounded corners. According to the fourth aspect, by approximating the bottom of each of the plurality of recesses to a rectangular shape, deformation due to a load in a direction along the sides of the rectangle can be suitably suppressed.

[0099] A fifth aspect of the present invention is the reinforcing member according to any one of the first to fourth aspects, configured so that the radii of curvature of the first and second faces in a cross-sectional view perpendicular to the outer edge of the plate-like member are 20 mm or more. According to the fifth aspect, by making the radii of curvature of the first and second faces 20 mm or more, it becomes easy to uniformly arrange continuous fibers along the first and second faces, and the overall rigidity of the reinforcing member can be improved.

[0100] A sixth aspect of the present invention is the reinforcing member according to any one of the first to fifth aspects, wherein the fiber-reinforced resin includes a continuous fiber sheet woven with a plurality of continuous fibers extending in a first direction and a plurality of continuous fibers extending in a second direction intersecting the first direction. According to the sixth aspect, by using a continuous fiber sheet woven with a plurality of continuous fibers extending in a first direction and a second direction intersecting each other, deformation such as bending against loads in both the longitudinal direction and the direction intersecting the longitudinal direction of the reinforcing member can be suitably suppressed.

[0101] A seventh aspect of the present invention is the reinforcing member according to any one of the first to sixth aspects, which is made of fiber-reinforced resin and further includes a rib extending from the first surface or the second surface. According to the seventh aspect, by providing a rib on the first surface or the second surface of the plate-like member, the rigidity of the reinforcing member can be further improved.

[0102] An eighth aspect of the present invention is the reinforcing member according to the seventh aspect, wherein the rib includes a first rib extending from the first surface inside at least one of the recesses. According to the eighth aspect, by providing the first rib inside the recess, deformation of the recess can be more suitably suppressed, and the rigidity of the reinforcing member can be further improved.

[0103] A ninth aspect of the present invention is the reinforcing member according to the seventh or eighth aspect, wherein the rib further comprises a second rib extending from the second surface inside the protrusion. According to the ninth aspect, by providing the second rib inside the protrusion, deformation of the protrusion can be more suitably suppressed, and the rigidity of the reinforcing member can be further improved.

[0104] A tenth aspect of the present invention is the reinforcing member according to the ninth aspect, wherein the second rib connects between a bottom portion of at least one of the recesses and the outer periphery. According to the tenth aspect, by providing a second rib connecting between the bottom portion and the outer periphery, deformation of the bottom portion relative to the outer periphery can be more suitably suppressed, and the rigidity of the reinforcing member can be further improved.

[0105] An eleventh aspect of the present invention is the reinforcing member according to the ninth or tenth aspect, wherein the second rib connects two bottoms of the plurality of recesses. According to the eleventh aspect, by providing the second rib connecting the two bottoms, deformation of the bottoms can be more suitably suppressed, and the rigidity of the reinforcing member can be further improved.

[0106] A twelfth aspect of the present invention is the reinforcing member according to any one of the first to eleventh aspects, wherein the fiber reinforced resin has a resin weight content of 50% or less. According to the twelfth aspect, the resin weight content of the fiber reinforced resin is 50% or less, whereby the rigidity of the reinforcing member can be further improved.

[0107] A thirteenth aspect of the present invention is a joined structure comprising the reinforcing member according to any one of the first to twelfth aspects, and a main body member joined to the outer periphery of the reinforcing member and to the bottoms of each of the plurality of recesses, and a cavity is provided between the reinforcing member and the main body member. According to the thirteenth aspect, by joining the reinforcing member to the main body member, the deformation of the main body member can be suppressed by the reinforcing member, and a joined structure with excellent rigidity can be provided. In addition, since a cavity is provided between the reinforcing member and the main body member, a joined structure that is lightweight and has high rigidity can be provided.

[0108] A fourteenth aspect of the present invention is a manufacturing method comprising the steps of: arranging a prepreg sheet in which continuous fibers are impregnated with resin on a die for molding a plate-shaped member having an outer periphery defining an outer edge of the plate-shaped member having a first surface and a second surface; a convex portion inside the outer periphery that is convex on the first surface side; and a plurality of concave portions inside the convex portions that are concave on the first surface side; and heating and pressurizing the prepreg sheet using the die to mold a reinforcing member comprising the plate-shaped member made of fiber-reinforced resin. According to the fourteenth aspect, the reinforcing member can be manufactured by forming the prepreg sheet using a die, so that the manufacturing process of the reinforcing member can be simplified. In addition, by using a prepreg sheet in which continuous fibers are impregnated with resin, the arrangement of the prepreg can be simplified compared to the case of using small cut prepregs, and the rigidity of the molded reinforcing member can be improved.

[0109] A fifteenth aspect of the present invention is the manufacturing method according to the fourteenth aspect, in which the prepreg sheet is formed by knitting a plurality of first prepreg tapes extending in a first direction and a plurality of second prepreg tapes extending in a second direction intersecting the first direction, and each of the plurality of first prepreg tapes and the plurality of second prepreg tapes is formed by impregnating a plurality of continuous fibers extending in a single direction with the resin. According to the fifteenth aspect, the gap between the prepreg tapes is variable in accordance with the uneven shape of the mold during molding, so that it is easy to arrange the prepreg tapes more uniformly along the uneven shape of the mold. As a result, a reinforcing member in which the prepreg tapes are uniformly arranged can be molded, and the rigidity of the reinforcing member can be improved.

[0110] A sixteenth aspect of the present invention is the method according to the fourteenth aspect, in which the prepreg sheet is formed by impregnating a continuous fiber sheet made of a plurality of first continuous fibers extending in a first direction and a plurality of second continuous fibers extending in a second direction intersecting the first direction with the resin. According to the sixteenth aspect, the rigidity of the molded reinforcing member can be improved by using a continuous fiber sheet made of a plurality of continuous fibers extending in a first direction and a second direction intersecting each other.

[0111] A seventeenth aspect of the present invention is a manufacturing method according to any one of the fourteenth to sixteenth aspects, in which the mold has a groove for forming a rib extending from the first surface or the second surface, and further includes a step of filling the groove of the mold with prepreg, and the mold is used to heat and pressurize the prepreg sheet and the prepreg, thereby molding the reinforcing member in which the rib made of fiber reinforced resin is joined to the first surface or the second surface of the plate-like member. According to the seventeenth aspect, since the rib can be formed on the reinforcing member, the rigidity of the molded reinforcing member can be further improved. By filling the groove of the mold with prepreg, a reinforcing member in which the plate-like member and the rib are integrated can be easily manufactured.

[0112] An 18th aspect of the present invention is the manufacturing method according to any one of the 14th to 17th aspects, further comprising a step of joining the outer periphery of the reinforcing member and the bottoms of each of the plurality of recesses to a surface of a main body member to form a joined structure. According to the 18th aspect, by joining the reinforcing member to the surface of the main body member, a lightweight and highly rigid joined structure can be easily manufactured.

[0113] A nineteenth aspect of the present invention is a bonding method including the steps of: disposing a metal member having a first surface on which a first metal oxide particle cluster is formed and a second surface on which a second metal oxide particle cluster is formed, the metal member having a thickness of 1 mm or less from the first surface to the second surface, between a first member containing a first thermoplastic resin and a second member containing a second thermoplastic resin; and heating and pressurizing the metal member between the first member and the second member to bond the first surface to the first resin and bond the second surface to the second resin. According to the nineteenth aspect, by using a metal member on which metal oxide particle clusters are formed, the thermoplastic resin and the metal member can be firmly bonded, and the bonding strength between the first member and the second member can be improved. In addition, by making the thickness of the metal member 1 mm or less, the weight increase due to the addition of the metal member can be suppressed, and a bonded structure that is lightweight and has excellent rigidity can be provided.

[0114] A twentieth aspect of the present invention is the joining method according to the 19th aspect, in which the metal members are heated by at least one of irradiating the metal members with electromagnetic waves, passing a current through the metal members, and applying a magnetic field to the metal members. According to the twentieth aspect, by heating the metal members, only the surfaces of the first member and the second member in contact with the metal members can be heated and softened to join them. This makes it possible to suppress deformation of the first member and the second member due to heating, and improve the quality of the joined structure.

[0115] A 21st aspect of the present invention is the joining method according to the 19th or 20th aspect, wherein the metal members have a joining portion located between the first member and the second member and an extending portion extending from between the first member and the second member, and the metal members are heated by at least one of irradiating the extending portion with electromagnetic waves, passing a current through the extending portion, and applying a magnetic field to the extending portion. According to the 21st aspect, by providing an extending portion extending from between the first member and the second member, the metal members sandwiched between the first member and the second member can be effectively heated.

[0116] A 22nd aspect of the present invention is the joining method according to the 21st aspect, further comprising a step of removing the extending portion after joining the joining portion to the first member and the second member. According to the 22nd aspect, by removing the extending portion that does not contribute to the joining, a lighter joined structure can be provided.

[0117] A 23rd aspect of the present invention is the joining method according to any one of the 19th to 22nd aspects, further comprising a step of preheating the metal member before placing it between the first member and the second member. According to the 23rd aspect, by preheating the metal member, it is possible to shorten the heating step after sandwiching the metal member between the first member and the second member, and thus it is possible to improve productivity.

[0118] A 24th aspect of the present invention is the joining method according to any one of the 19th to 23rd aspects, in which at least one of the first member and the second member is made of a fiber-reinforced resin including reinforcing fibers extending in a direction along the first surface or the second surface. According to the 24th aspect, by using a fiber-reinforced resin, a joined structure that is lightweight and has high rigidity can be provided.

[0119] A 25th aspect of the present invention is the joining method according to the 24th aspect, wherein the reinforcing fibers include carbon fibers, glass fibers, or aramid fibers. According to the 25th aspect, by using carbon fibers, glass fibers, or aramid fibers as the reinforcing fibers, a lightweight and highly rigid joined structure can be provided.

[0120] A 26th aspect of the present invention is the joining method according to any one of the 19th to 25th aspects, in which at least one of the first resin and the second resin is aromatic polyetherketone (PAEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyphenylene sulfide (PPS), polyetherimide (PEI), or polyethersulfone (PES). According to the 26th aspect, by using an engineering plastic as the first resin or the second resin, a joined structure that is lightweight and highly rigid can be provided.

[0121] A 27th aspect of the present invention is the bonding method according to any one of the 19th to 26th aspects, wherein the metal member comprises a steel material, an aluminum material, an aluminum alloy material, a titanium material, a titanium alloy material, a nickel-titanium alloy material, a copper material, or a copper alloy material. According to the 27th aspect, by using these metal materials, the bonding strength between the metal oxide particle clusters and the resin can be improved.

[0122] A 28th aspect of the present invention is the joining method according to any one of the 19th to 27th aspects, in which the metal member includes an outer peripheral joining portion joined to the outer peripheral portion of the second member, an inner joining portion joined to a portion of the second member away from the outer peripheral portion, and a connecting portion connecting the outer peripheral joining portion and the inner joining portion. According to the 28th aspect, by providing a connecting portion connecting the outer peripheral joining portion and the inner joining portion of the metal member, it is possible to appropriately heat the inner joining portion and improve the joining strength at the inner joining portion.

[0123] A 29th aspect of the present invention is the joining method according to the 28th aspect, in which the connection portion is not joined to the first member or the second member. According to the 29th aspect, the connection portion comes into contact with the first member or the second member at a location where joining is not required, and deformation of the first member or the second member due to heating can be suppressed. Also, by providing a connection portion that is not joined to the first member or the second member, the inner joining portion can be appropriately positioned at the joining location.

[0124] A 30th aspect of the present invention is a bonded structure including a first member containing a first thermoplastic resin, a second member containing a second thermoplastic resin, and a metal member having a first surface on which a first metal oxide particle cluster bonded to the first resin of the first member is formed, and a second surface on which a second metal oxide particle cluster bonded to the second resin of the second member is formed, the thickness from the first surface to the second surface being 5 μm or more and 1 mm or less. According to the 30th aspect, by using the metal member on which the metal oxide particle cluster is formed, it is possible to firmly bond the thermoplastic resin, and the bonding strength between the first member and the second member can be improved. In addition, by making the thickness of the metal member 1 mm or less, it is possible to suppress the weight increase due to the addition of the metal member, and it is possible to provide a bonded structure that is lightweight and has excellent rigidity. [Explanation of symbols]

[0125] Reference Signs List 10,110,200...jointed structure, 12...main body member, 14...reinforcing member, 16...plate-shaped member, 16a...first surface, 16b...second surface, 18...outer edge, 20...periphery, 22...convex portion, 24...concave portion, 26...outer edge, 28...top, 30...outer inclined portion, 32...outer edge, 34...bottom, 36...inner inclined portion, 50...prepreg tape, 52...reinforcing fiber, 54...thermoplastic resin, 56...first prepreg tape, 58...second prepreg tape , 60...prepreg sheet, 210...first member, 220...second member, 230, 250...metal members, 232...first surface, 234...second surface, 236...first metal oxide particle cluster, 238...second metal oxide particle cluster, 240...joining portion, 242...first extension portion, 244...second extension portion, 252...peripheral joining portion, 254...inner joining portion, 256...extension portion, 258...first connecting portion, 260...second connecting portion.

Claims

1. a step of disposing a metal member having a first surface on which first metal oxide particle clusters are formed and a second surface on which second metal oxide particle clusters are formed, the metal member having a thickness of 1 mm or less from the first surface to the second surface, between a first member containing a first thermoplastic resin and a second member containing a second thermoplastic resin; a step of heating and pressurizing the metal member between the first member and the second member to bond the first surface with the first resin and to bond the second surface with the second resin.

2. The joining method according to claim 1 , wherein the metal members are heated by at least one of irradiating the metal members with electromagnetic waves, passing a current through the metal members, and applying a magnetic field to the metal members.

3. the metal member includes a joint portion located between the first member and the second member, and an extension portion extending from between the first member and the second member, The joining method according to claim 1 , wherein the metal members are heated by at least one of irradiating the extended portion with electromagnetic waves, passing a current through the extended portion, and applying a magnetic field to the extended portion.

4. The joining method according to claim 3 , further comprising the step of removing the extending portion after joining the joining portion to the first member and the second member.

5. The method of claim 1 further comprising the step of preheating the metal member prior to disposing the metal member between the first member and the second member.

6. The joining method according to claim 1 , wherein at least one of the first member and the second member is made of a fiber-reinforced resin including reinforcing fibers extending in a direction along the first surface or the second surface.

7. The method of claim 6 , wherein the reinforcing fibers comprise carbon fibers, glass fibers, or aramid fibers.

8. 6. The bonding method according to claim 1, wherein at least one of the first resin and the second resin is aromatic polyetherketone (PAEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyphenylene sulfide (PPS), polyetherimide (PEI), or polyethersulfone (PES).

9. The joining method according to claim 1 , wherein the metal member comprises a steel material, an aluminum material, an aluminum alloy material, a titanium material, a titanium alloy material, a nickel-titanium alloy material, a copper material, or a copper alloy material.

10. The joining method according to any one of claims 1 to 5, wherein the metal member comprises an outer peripheral joining portion joined to an outer peripheral portion of the second member, an inner joining portion joined to a portion of the second member away from the outer peripheral portion, and a connecting portion connecting the outer peripheral joining portion and the inner joining portion.

11. The joining method according to claim 10 , wherein the connection portion is not joined to the first member or the second member.

12. a first member including a first thermoplastic resin; a second member including a second thermoplastic resin; a metal member having a first surface on which a first metal oxide particle cluster is formed and which bonds with the first resin of the first member, and a second surface on which a second metal oxide particle cluster is formed and which bonds with the second resin of the second member, the thickness from the first surface to the second surface being 5 μm or more and 1 mm or less.

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