Composite structure and method of manufacturing the same

Abstract

To provide a composite structure allowed to facilitate mold release and a method of manufacturing the same.SOLUTION: A composite structure 100 has a bottom plate 1 and a pair of first side plates 3 erected from side edges of the bottom plate 1 and also comprises outer and inner plate materials 10 and 20 formed of metal and a foam 30 formed of a foam material. The outer plate material 10 has an outer bottom-plate portion 11, a first outer side-plate portion 13, an outer surface 10a and an outer opposed surface 10b. The inner plate material 20 has an inner bottom-plate portion 21, a first inner side-plate portion 23, an inner surface 20a and an inner opposed surface 20b. The foam 30 is charged between the outer opposed surface 10b and the inner opposed surface 20b. The outer plate material 10 has an outer rugged portion 16 provided on the outer surface 10a. The inner plate material 20 has an inner rugged portion 26 provided on the inner surface 20a.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a composite structure and a method for manufacturing the same.

Background Art

[0002] Patent Document 1 discloses an air conditioner cabinet formed of a composite material of a metal plate and a foaming material. In the manufacturing process, a mold composed of a convex core and a concave upper mold is used. The metal plate is set in the mold in a state of being floated in the cavity by pins. Foaming beads are injected on both sides of the metal plate in the cavity and heated by steam. Then, the upper mold is separated from the core, and the product is taken out from the molding die.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The beads expand due to steam heating. As a result, the contact resistance between the foaming material and the mold increases, making it difficult to release the mold.

[0005] The above cabinet is a three-layer structure box body provided with foaming materials on both sides of the metal plate. Even when the metal plate and the foaming material are reversed, that is, when the structure is composed of a three-layer structure with metal plates provided on both sides of the foaming material, similar problems are considered to occur due to the expansion of the beads. Moreover, the contact resistance is considered to be even greater.

[0006] An object of the present invention is to provide a composite structure and a method for manufacturing the same that can facilitate mold release.

Means for Solving the Problems

[0007] One aspect of the present invention is a composite structure including a bottom plate and a pair of side plates erected from the edges of the bottom plate, the composite structure including an outer bottom plate portion constituting the bottom plate, an outer side plate portion constituting the pair of side plates, outer surfaces of the outer bottom plate portion and the outer side plate portion, and outer opposing surfaces on the opposite sides thereof, the outer plate material formed of metal, an inner bottom plate portion constituting the bottom plate, an inner side plate portion constituting the pair of side plates, inner surfaces of the inner bottom plate portion and the inner side plate portion, and inner opposing surfaces on the opposite sides thereof, the inner plate material formed of metal, and a foam formed of a foaming material and filled between the outer opposing surfaces and the inner opposing surfaces, the outer plate material having outer uneven portions provided on the outer surfaces, and the inner plate material having inner uneven portions provided on the inner surfaces.

[0008] According to the above configuration, the composite structure has at least a bottom plate and a pair of side plates, such as in a channel shape or a box shape. Further, the composite structure is configured in a three-layer structure in which metal plates are provided on both sides of a foaming material and can be manufactured, for example, by molding.

[0009] When the composite structure is manufactured by molding, the outer surface of the outer plate material and the inner surface of the inner plate material can come into contact with the surface of the mold. The outer uneven portions are provided on this outer surface. Microscopically, the outer surface contacts the surface of the mold at the convex portions while being separated from the surface of the mold at the concave portions. Even when the foaming material is expanded in the mold, the separated state of the concave portions can be maintained. Since the contact area between the outer surface and the surface of the mold becomes small, the contact resistance also becomes small accordingly. The inner uneven portions provided on the inner surface also act in the same manner. Therefore, demolding is facilitated.

[0010] The outer uneven portions may be provided on the outer opposing surfaces, the inner uneven portions may be provided on the inner opposing surfaces, and the foam may be engaged with the outer uneven portions and the inner uneven portions.

[0011] According to the above configuration, the bonding strength of the foam to the outer plate material and the inner plate material is improved.

[0012] The outer uneven portions and the inner uneven portions may be formed by arranging a plurality of concave portions or a plurality of convex portions.

[0013] According to the above configuration, for example, by embossing or forging, the outer concavo-convex portions can be easily provided on both sides of the outer plate material, and the inner concavo-convex portions can be easily provided on both sides of the inner plate material.

[0014] The composite structure may further include a pair of second side plates erected from the edge of the bottom plate, and the pair of side plates and the pair of second side plates may constitute the peripheral plate of the box body.

[0015] According to the above configuration, a box-shaped composite structure with facilitated mold release can be provided. The composite structure is composed of a three-layer structure in which metal plates are provided on both sides of a foaming material, and is excellent in robustness and heat insulation. A structure suitable for transporting goods that require temperature control can be efficiently produced.

[0016] Another aspect of the present invention is a method for manufacturing a composite structure including a bottom plate and a pair of side plates erected from the edge of the bottom plate, the method including: forming an outer plate material having an outer bottom plate portion constituting the bottom plate, an outer side plate portion constituting the pair of side plates, an outer surface of the outer bottom plate portion and the outer side plate portion, and an outer opposing surface on the opposite side thereof with metal; forming an inner plate material having an inner bottom plate portion constituting the bottom plate, an inner side plate portion constituting the pair of side plates, an inner surface of the inner bottom plate portion and the inner side plate portion, and an inner opposing surface on the opposite side thereof with metal; a mold including a first mold having a mold recess and a second mold having a mold protrusion, when the mold protrusion is in a mold opening state where it has retreated from the mold recess, fitting the outer plate material into the mold recess and fitting the inner plate material onto the mold protrusion; closing the mold to a mold closing state where the mold protrusion enters the mold recess; filling a foaming material into a cavity formed between the outer opposing surface and the inner opposing surface; heating the foaming material to form a foam between the outer plate material and the inner plate material; opening the mold and taking out the composite structure from the mold, and in the step of forming the outer plate material, outer concavo-convex portions are provided on the outer surface, and in the step of forming the inner plate material, inner concavo-convex portions are provided on the inner surface.

[0017] Even in the above configuration, the composite structure has at least a bottom plate and a pair of side plates, for example, in the form of a channel type or a box type. Further, the composite structure is composed of a three-layer structure in which metal plates are provided on both sides of the foaming material and is manufactured by molding. The outer surface of the outer plate material is close to the surface of the mold recess. In this regard, since the outer uneven portion is provided on the outer surface of the outer plate material, the convex portion contacts the surface of the mold recess while the concave portion is separated from the surface of the mold recess. Even when the foaming material is heated and expands in the cavity, the separated state of the concave portion can be maintained. The contact area between the outer surface and the mold becomes smaller, and the contact resistance also becomes smaller accordingly. The inner surface of the inner plate material and the surface of the mold protrusion also act in the same manner. Therefore, the process of taking out the composite structure from the mold, that is, the demolding is facilitated.

[0018] The outer uneven portion is provided on the outer facing surface, the inner uneven portion is provided on the inner facing surface, and in the step of heating the foaming material, the foam may enter and engage with the outer uneven portion and the inner uneven portion.

[0019] According to the above configuration, the foam engages with the outer plate material and the inner plate material at the outer uneven portion and the inner uneven portion, and the relative movement between the outer plate material and the foam, and the relative movement between the inner plate material and the foam are prevented. As a result, the three members of the outer plate material, the inner plate material, and the foam can be integrated without separating from each other.

[0020] The outer uneven portion and the inner uneven portion may be provided on the sliding surface with the mold among the outer surface and the inner surface.

[0021] According to the above configuration, the demolding can be effectively facilitated.

[0022] The step of forming the outer plate material includes a step of forming a flat blank having the outer bottom plate portion and the outer side plate portion in a developed state, and a step of performing bending on the blank so that the outer side plate portion stands up from the outer bottom plate portion. The outer uneven portion may be provided on the blank before the step of performing the bending.

[0023] According to the above configuration, in the forming process of the outer plate material, the outer concave and convex portions can be easily provided, and the production efficiency of the outer plate material is improved.

Effect of the Invention

[0024] According to the present invention, it is possible to provide a composite structure that can facilitate mold release and a method for manufacturing the same.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 5C

Figure 5D

Figure 6A

Figure 6B

Figure 7

Figure 8

Figure 9

Figure 10A

Figure 10B

Embodiment for Carrying out the Invention

[0026] Hereinafter, embodiments will be described with reference to the drawings. In the drawings, the same or corresponding elements are denoted by the same reference numerals throughout, and redundant detailed descriptions are omitted.

[0027] Referring to FIG. 1, the composite structure 100 according to the present embodiment is box-shaped as a whole and is suitably used for transporting luggage, for example. The composite structure 100 has a bottom plate 1, a peripheral plate 2, and a flange 5. The bottom plate 1 and the peripheral plate 2 constitute a box body that is open upward. The inner surface of the bottom plate 1 and the inner surface of the peripheral plate 2 define an internal space 6 capable of storing luggage or the like.

[0028] The bottom plate 1 is, for example, rectangular in plan view. The bottom plate 1 has a pair of first edges 1a and a pair of second edges 1b as four edges defining a rectangle. The pair of first edges 1a are parallel to each other, the pair of second edges 1b are parallel to each other, and the second edge 1b extends in a direction orthogonal to the first edge 1a. The peripheral plate 2 stands up from the edge of the bottom plate 1. The peripheral plate 2 includes a total of four side plates, namely a pair of first side plates 3 and a pair of second side plates 4. The pair of first side plates 3 stand up from each of the pair of first edges 1a, and the pair of second side plates 4 stand up from each of the pair of second edges 1b. The flange 5 is provided at the upper end edge of the peripheral plate 2. The flange 5 is rectangular window frame-shaped in plan view and defines the upper opening of the box body.

[0029] Referring to FIGS. 1 to 3, the composite structure 100 includes an outer plate member 10 formed of metal, an inner plate member 20 formed of metal, and a foam 30 formed of a foam material, and the foam 30 is sandwiched between the outer plate member 10 and the inner plate member 20. In other words, the composite structure 100 is configured by a three-layer structure in which the metal outer plate member 10 and the inner plate member 20 are provided on both sides of the foam 30.

[0030] As the metal for the outer plate member 10, steel or an aluminum alloy can be preferably used. The same applies to the inner plate member 20. The outer plate member 10 and the inner plate member 20 may be formed of the same metal or different metals. As the foaming material for the foam body 30, polyurethane, polystyrene, or polyolefin can be preferably used.

[0031] The three-layer structure is applied to the entire bottom plate 1 and peripheral plate 2. That is, the outer plate member 10, the foam body 30, and the inner plate member 20 are also box bodies that are open upward, similar to the composite structure 100 as a finished product. The flange 5 is composed of a two-layer structure of the outer plate member 10 and the foam body 30.

[0032] In FIG. 2, the outer plate member 10, the inner plate member 20, and the foam body 30 are shown in a separated state for the sake of convenience of explanation. As will be described later, the foam body 30 is integrally formed with the outer plate member 10 and the inner plate member 20 by molding. In the manufacturing process of the composite structure 100, the foam body 30 of the box body is not handled alone as a single item.

[0033] The outer plate member 10 has an outer bottom plate portion 11 that constitutes the bottom plate 1, an outer peripheral plate portion 12 that constitutes the peripheral plate 2, and a lower flange portion 15 that constitutes the flange 5. The outer peripheral plate portion 12 includes a pair of first outer side plate portions 13 corresponding to the respective first side plates 3 and a pair of second outer side plate portions 14 corresponding to the respective second side plates 4.

[0034] The outer plate member 10 has an outer surface 10a and an outer opposing surface 10b on the side opposite to the outer surface 10a in the plate thickness direction. The outer surface 10a corresponds to the outer surface of the composite structure 100. The outer surface of the outer bottom plate portion 11 corresponds to the outer surface (lower surface) of the bottom plate 1, and the outer surface of the outer peripheral plate portion 12 corresponds to the outer surface (outer side surface) of the peripheral plate 2.

[0035] The inner plate member 20 has an inner bottom plate portion 21 that constitutes the bottom plate 1 and an inner peripheral plate portion 22 that constitutes the peripheral plate 2. The inner peripheral plate portion 22 includes a pair of first inner side plate portions 23 corresponding to the respective pair of first side plates 3 and a pair of second inner side plate portions 24 corresponding to the respective pair of second side plates 4.

[0036] The inner plate member 20 has an inner surface 20a and an inner opposing surface 20b on the side opposite to the inner surface 20a in the plate thickness direction. The inner surface 20a corresponds to the inner surface of the composite structure 100 and defines the internal space 6. The inner surface of the inner bottom plate portion 21 corresponds to the inner surface (upper surface) of the bottom plate 1, and the inner surface of the inner peripheral plate portion 22 corresponds to the inner surface (inner side surface) of the peripheral plate 2.

[0037] The foam body 30 has a middle bottom plate portion 31 that constitutes the bottom plate 1, a middle peripheral plate portion 32 that constitutes the peripheral plate 2, and an upper flange portion 35 that constitutes the flange 5. The middle peripheral plate portion 32 includes a pair of first middle side plate portions 33 corresponding to the respective pair of first side plates 3 and a pair of second middle side plate portions 34 corresponding to the respective pair of second side plates 4.

[0038] The foam body 30 is filled between the outer opposing surface 10b of the outer plate member 10 and the inner opposing surface 20b of the inner plate member 20. The foam body 30 has an outer surface 30a and an inner surface 30b on the side opposite to the outer surface 30a in the plate thickness direction. The outer surface 30a is in close contact with the outer opposing surface 10b, and the inner surface 30b is in close contact with the inner opposing surface 20b.

[0039] The bottom plate 1 is configured by laminating the outer bottom plate portion 11, the middle bottom plate portion 31, and the inner bottom plate portion 21 in this order from the outside to the inside of the composite structure 100 in the plate thickness direction of the bottom plate 1. The first side plate 3 is configured by laminating the first outer side plate portion 13, the first middle side plate portion 33, and the first inner side plate portion 23 in this order from the outside to the inside of the composite structure 100 in the plate thickness direction of the first side plate 3. The same applies to the second side plate 4, the second outer side plate portion 14, the second middle side plate portion 34, and the second inner side plate portion 24 as to the first side plate 3.

[0040] The flange 5 is configured by laminating the upper flange portion 35 of the foam 30 on the upper surface side of the lower flange portion 15 of the outer plate material 10. The upper surface of the lower flange portion 15 is formed by a part of the outer facing surface 10b, the lower surface of the upper flange portion 35 is formed by a part of the outer surface 30a, and it is in close contact with the upper surface of the lower flange portion 15. The lower surface of the flange 5 as a whole is formed by the outer plate material 10. The upper surface of the flange 5 as a whole is formed by the foam 30 and is positioned at substantially the same height as the upper end edge of the inner peripheral plate portion 22 of the inner plate material 20.

[0041] The outer plate material 10 has outer concavo-convex portions 16 provided on the outer surface 10a side. The outer concavo-convex portions 16 are configured by forming a plurality of convex portions 16a on the outer surface 10a. Each convex portion 16a is formed by denting the outer facing surface 10b toward the outer surface 10a side in the thickness direction of the outer plate material 10 and is island-shaped. The plurality of convex portions 16a are arranged within a specific region of the outer surface 10a. In the region of the outer surface 10a where the plurality of convex portions 16a are arranged, the locations where the convex portions 16a are not actually formed are recessed toward the outer facing surface 10b side in the thickness direction relative to the locations where the convex portions 16a are actually formed. Even if only the convex portions 16a are formed on the outer surface 10a, it is possible to substantially provide concavo-convexities on the outer surface 10a.

[0042] The convex portion 16a is formed by pressing (such as embossing) that applies a pressing force to the outer facing surface 10b as described later. By forming the plurality of convex portions 16a on the outer surface 10a, a plurality of concave portions 16b are transferred to the outer facing surface 10b. Each concave portion 16b is formed by denting the outer facing surface 10b toward the outer surface 10a side in the thickness direction of the outer plate material 10 and is pool-shaped. In the region of the outer facing surface 10b where the plurality of concave portions 16b are arranged, the locations where the concave portions 16b are not actually formed protrude toward the outer facing surface 10b side in the thickness direction relative to the locations where the concave portions 16b are actually formed. Even if only the concave portions 16b are formed on the outer facing surface 10b, it is possible to substantially provide concavo-convexities on the outer facing surface 10b. In this way, the outer concavo-convex portions 16 are provided on the outer surface 10a and are also simultaneously provided on the outer facing surface 10b.

[0043] The inner plate 20 has inner uneven portions 26 provided on the inner surface 20a side. The inner uneven portions 26 are constituted by forming a plurality of convex portions 26a on the inner surface 20a. Each convex portion 26a is formed by recessing the inner opposing surface 20b toward the inner surface 20a side in the plate thickness direction of the inner plate 20. The plurality of convex portions 26a are arranged within a specific region of the inner surface 20a. In the region of the inner surface 20a where the plurality of convex portions 26a are arranged, even if only the convex portions 26a are actually formed, substantial unevenness is provided.

[0044] The convex portions 26a are formed in the same manner as the convex portions 16a. By forming the plurality of convex portions 26a on the inner surface 20a, a plurality of concave portions 26b are transferred to the inner opposing surface 20b. Each concave portion 26b is formed by indenting the inner opposing surface 20b toward the inner surface 20a side in the plate thickness direction of the inner plate 20. In the region of the inner opposing surface 20b where the plurality of concave portions 26b are arranged, even if only the concave portions 26b are actually formed, substantial unevenness is provided. In this way, the inner uneven portions 26 are provided on the inner surface 20a and are simultaneously provided on the inner opposing surface 20b.

[0045] When the outer uneven portion 16 is constituted by a plurality of convex portions 16a or concave portions 16b, the arrangement pattern of these convex portions 16a and concave portions 16b may be regular such as in a matrix shape or a staggered shape, or may be irregular. The shapes of the convex portions 16a and concave portions 16b are not particularly limited. In addition to the circular shape shown in the figure, other shapes such as an elliptical shape, a regular polygonal shape, or a star shape may be applied. The convex portions 16a may be formed on the outer opposing surface 10b and the concave portions 16b may be formed on the outer surface 10a. However, when the convex portions 16a are formed on the outer surface 20a, it is beneficial in terms of easily obtaining the contact area reduction effect described later. The region where the outer uneven portion 16 is provided (the region where the plurality of convex portions 16a or concave portions 16b are arranged) is at least the sliding surface with the mold 50 (see FIG. 7). Note that the same applies when the inner uneven portion 26 is constituted by a plurality of convex portions 26a or concave portions 26b.

[0046] The foam 30 is engaged with the outer concavo-convex portion 16 on the outer surface side and engaged with the inner concavo-convex portion 26 on the inner surface side. Concavities and convexities are transferred to the outer surface 30a of the foam 30 so as to engage with the outer concavo-convex portion 16. Concavities and convexities are transferred to the inner surface 30b of the foam 30 so as to engage with the inner concavo-convex portion 26.

[0047] FIG. 4 shows a method for manufacturing the composite structure according to the present embodiment. In manufacturing the composite structure 100, first, the outer plate member 10 is formed of metal (step S1, see FIG. 5), and the inner plate member 20 is formed of metal (step S2, see FIG. 6). Next, when the mold 50 is in the open state, the outer plate member 10 and the inner plate member 20 are installed in the mold 50 (step S3, see FIG. 7), and the mold 50 is closed (step S4, see FIG. 8). Next, the foam beads 30A are filled into the cavity 53 (step S5, see FIG. 8), and the foam beads 30A are heated (step S6, see FIG. 9). Next, the mold 50 is opened (step S7, see FIGS. 10A and 10B), and the composite structure 100 is taken out of the mold 50 (step S8). Thereby, the composite structure 100 as shown in FIG. 1 is obtained.

[0048] FIGS. 5A and 6A are explanatory views of the steps (steps S1 and S2) of forming the outer plate member 10 and the inner plate member 20.

[0049] Referring to FIG. 5A, in forming the outer plate member 10, a flat blank 10A having an outer bottom plate portion 11, an outer peripheral plate portion 12 (a first outer side plate portion 13 and a second outer side plate portion 14), and a lower flange portion 15 in a developed state is formed. The blank 10A is formed, for example, by punching a plate material drawn from a metal coil. FIG. 5A is a developed view of the outer plate member 10 and also a plan view of the blank 10A of the outer plate member 10. Then, by performing required bending on the blank 10A, the outer peripheral plate portion 12 is formed so as to stand up from the outer bottom plate portion 11, and the lower flange portion 15 is formed so as to bend from the outer peripheral plate portion 12. Further, after the bending, two adjacent ones of the four outer side plate portions of the pair of first outer side plate portions 13 and the pair of second outer side plate portions 14 are welded to each other. Thereby, the outer plate member 10 is formed into a box shape.

[0050] As shown in FIG. 5A as a plan view of the blank 10A, the outer concavo-convex portion 16 is provided on the blank 10A before bending. When providing the outer concavo-convex portion 16 on the outer plate member 10, embossing is performed on the outer surface 10a, a number of convex portions 16a are formed on the outer surface 10a, and a number of concave portions 16b are formed on the outer opposing surface 10b. In the present embodiment, the region where the outer concavo-convex portion 16 is provided is, for example, the entire outer bottom plate portion 11 and the outer peripheral plate portion 12.

[0051] Referring to FIG. 6A, in the forming of the inner plate member 20, it is the same as the above-described outer plate member 10. A flat blank 20A having an inner bottom plate portion 21 and an inner peripheral plate portion 22 (a first inner side plate portion 23 and a second inner side plate portion 24) in a developed state is formed. FIG. 6 is a developed view of the inner plate member 20 and is also a plan view of the blank 20A of the inner plate member 20. By performing required bending on this blank 20A, the inner peripheral plate portion 22 is formed so as to stand up from the inner bottom plate portion 21. After bending, welding is performed on the inner peripheral plate portion 22 in the same manner as the outer plate member 10. Thereby, the inner plate member 20 is formed into a box shape.

[0052] The inner concavo-convex portion 26 is also provided on the blank 20A before bending. When providing the inner concavo-convex portion 26 on the inner plate member 20, embossing is performed on the inner surface 20a, a number of convex portions 26a are formed on the inner surface 20a, and a number of concave portions 26b are formed on the inner opposing surface 20b. In the present embodiment, the region where the inner concavo-convex portion 26 is provided is, for example, the entire inner bottom plate portion 21 and the inner peripheral plate portion 22.

[0053] Referring to FIG. 5B, as an example, the convex portions 16a and the concave portions 16b of the outer concavo-convex portion 16 are hemispherical. Therefore, the portion where the protruding height from the outer surface 10a of each convex portion 16a is maximum (the top portion of the convex portion 16a) is dot-like. In the present embodiment, the top portions of the plurality of convex portions 16a are at substantially the same height from each other. Referring to FIG. 6B, the same applies to the convex portions 26a and the concave portions 26b of the inner concavo-convex portion 26.

[0054] The protruding height of the convex portion 16a of the outer uneven portion 16 (or the depth of the concave portion 16b) is ○○○ to ○○○ μm. When a metal material is adopted for the outer plate material 10 and the protruding height is set in this way, even due to the expansion of the foamed beads 30A (see FIG. 8), it is possible to avoid the entire sliding surface of the outer plate material 10 being pressed against the mold 50 (see FIG. 8), and the effect of facilitating mold release described later can be obtained. Further, when the protruding height is set in this way, when the outer uneven portion 16 is stroked by hand, the presence of the unevenness can be sufficiently felt. That is, the presence or absence of the outer uneven portion 16 can be judged by human feeling. The same applies to the protruding height of the convex portion 26a of the inner uneven portion 26 (or the depth of the concave portion 26b).

[0055] FIG. 7 is an explanatory diagram of the step (step S3) of installing the outer plate material 10 and the inner plate material 20 in the mold 50.

[0056] The mold 50 includes a first mold 51 and a second mold 52. The first mold 51 has a mold concave portion 51A. The second mold 52 has a mold convex portion 52A. The second mold 52 is displaceable relative to the first mold 51. Due to this relative displacement, the mold 50 switches states between an open mold state in which the mold convex portion 52A retreats from the mold concave portion 51A and a closed mold state in which the mold convex portion 52A enters the mold concave portion 51A. FIG. 7 shows the open mold state of the mold 50. The first mold 51 may be a fixed mold and the second mold 52 may be a movable mold, or vice versa.

[0057] In the present embodiment, the relative displacement direction of the first mold 51 and the second mold 52 (that is, the mold opening and closing direction) corresponds to the direction of taking out the composite structure 100 from the mold 50 (that is, the mold release direction), and corresponds to the direction in which the composite structure 100 slides with respect to the mold 50 during mold release (that is, the product sliding direction). In the following description, the mold opening and closing direction, the mold release direction, and the product sliding direction are assumed to correspond to the vertical direction according to the illustration, but these directions can be appropriately changed to other directions, such as the horizontal direction.

[0058] The first mold 51 has a rectangular box-shaped first main body portion 51a that is open upward and a shoulder portion 51b that protrudes outward from the upper end portion of the first main body portion 51a. The mold recess 51A is defined by the inner bottom surface and the inner peripheral surface of the first main body portion 51a. The shoulder portion 51b forms a stepped surface that extends outward from the upper end of the inner peripheral surface of the first main body portion 51a.

[0059] In the mold open state, the box-shaped outer plate material 10 is fitted into the mold recess 51A. The outer surface 10a of the outer plate material 10 is close to the inner surface of the mold recess 51A. The outer surface of the outer bottom plate portion 11 is close to the inner bottom surface of the mold recess 51A (the inner bottom surface of the first main body portion 51a), and the outer surface of the outer peripheral plate portion 12 is close to the inner peripheral surface of the mold recess 51A (the inner peripheral surface of the first main body portion 51a). The lower surface of the lower flange portion 15 is close to the stepped surface of the shoulder portion 51b.

[0060] The inner peripheral surface of the mold recess 51A extends upward from the inner bottom surface of the mold recess 51A, that is, in the mold opening / closing direction, the mold release direction, and the product sliding direction. As will be described later, the outer surface of the outer peripheral plate portion 12 can be in sliding contact with the inner surface of the mold recess 51A during mold release. That is, among the outer surfaces 10a of the outer plate material 10, the outer surface of the outer peripheral plate portion 12 is a sliding surface with the mold 50. In the present embodiment, the outer concavo-convex portion 16 is provided on this sliding surface. On the other hand, although the outer surface of the outer bottom plate portion 11 and the lower surface of the lower flange portion 15 are close to the surface of the first mold 51, they extend in a direction orthogonal to the mold opening / closing direction and cannot be said to be sliding surfaces. However, in the present embodiment, the outer concavo-convex portion 16 is also provided on the outer surface of the outer bottom plate portion 11.

[0061] The second mold 52 has a rectangular box-shaped second main body portion 52a that is open upward and a flange portion 52b that protrudes outward from the upper end portion of the first main body portion 51a. The mold protrusion 52A is defined by the outer bottom surface and the outer peripheral surface of the second main body portion 52a.

[0062] In the open mold state, the box-shaped inner plate member 20 is externally fitted onto the mold convex portion 52A. The inner surface 20a of the inner plate member 20 is close to the outer surface of the mold convex portion 52A. The inner surface of the inner bottom plate portion 21 is close to the outer bottom surface of the mold convex portion 52A (the outer bottom surface of the second main body portion 52a). The inner surface of the inner peripheral plate portion 22 is close to the outer peripheral surface of the mold convex portion 52A (the outer peripheral surface of the second main body portion 52a).

[0063] The outer peripheral surface of the mold convex portion 52A extends upward from the outer bottom surface of the mold convex portion 52A, that is, in the mold opening / closing direction, the mold release direction, and the product sliding direction. As will be described later, the outer surface of the inner peripheral plate portion 22 can be in sliding contact with the inner surface of the mold convex portion 52A during mold release. That is, among the inner surfaces 20a of the inner plate member 20, the inner surface of the inner peripheral plate portion 22 is a sliding surface with the mold 50. In the present embodiment, the inner concavo-convex portion 26 is provided on this sliding surface. On the other hand, although the inner surface of the inner bottom plate portion 21 is close to the surface of the second mold 52, it extends in a direction orthogonal to the mold opening / closing direction and cannot be said to be a sliding surface. However, in the present embodiment, the inner concavo-convex portion 26 is also provided on the inner surface of the inner bottom plate portion 21.

[0064] FIG. 8 is an explanatory diagram of the process of closing the mold 50 (step S4) and the process of filling the cavity 53 with the expandable beads 30A (step S5).

[0065] By relatively displacing the first mold 51 and the second mold 52, the state of the mold 50 is switched from the open mold state to the closed mold state. In the closed mold state, the mold convex portion 52A with the inner plate member 20 enters the mold concave portion 51A with the outer plate member 10. Inside the mold 50, a cavity 53 is formed between the outer opposing surface 10b of the outer plate member 10 and the inner opposing surface 20b of the inner plate member 20.

[0066] The flange portion 52b of the second mold 52 is internally fitted into the shoulder portion 51b of the first mold 51. The lower surface of the flange portion 52b is separated upward from the upper surface of the lower flange portion 15 of the outer plate member 10 supported on the stepped surface of the shoulder portion 51b. The space between the flange portion 52b and the lower flange portion 15 communicates with the space between the outer opposing surface 10b and the inner opposing surface 20b and constitutes a part of the cavity 53.

[0067] The mold 50 is provided with a bead port 54 for injecting the expandable beads 30A into the cavity 53. For example, the bead port 54 is a through hole formed in the flange portion 52b of the second mold 52. Since the inner plate member 20 does not cover the flange portion 52b, the external space of the mold 50 can be easily communicated with the cavity 53 through this through hole. Part or all of the bead port 54 may be provided on the shoulder portion 51b of the first mold 51.

[0068] In the mold-closed state, the expandable beads 30A are injected into the cavity 53 from the external space of the mold 50 through the bead port 54 using compressed air. Thereby, the expandable beads 30A are filled in the cavity 53.

[0069] FIG. 9 is an explanatory view of the step (step S6) of heating the expandable beads 30A.

[0070] The mold 50 is provided with a steam port 55 for supplying steam to the cavity 53. For example, the steam port 55 is a through hole formed in the second main body portion 52a of the second mold 52. The steam port 55 may also be formed in the first main body portion 51a of the first mold 51. Steam is supplied to the cavity 53 through the steam port 55, and the air in the cavity 53 is replaced with steam. Thereby, the expandable beads 30A are heated, and the expansion of the expandable beads 30A is promoted. Note that, for promoting the heating of the expandable beads 30A, the mold 50 is heated by a heater (not shown). After this heating step, the mold 50 and its interior are cooled by water cooling and natural cooling.

[0071] As a result of the heating step and the cooling step, the foam 30 is integrally formed with the outer plate member 10 and the inner plate member 20 in a state of being interposed therebetween, and a box-shaped composite structure 100 having a multilayer structure is configured. The foam 30 is fused to the outer facing surface 10b and the inner facing surface 20b to form the middle bottom plate portion 31 and the middle peripheral plate portion 32. The foam 30 is fused to the upper surface of the lower flange portion 15 of the outer plate member 10 to form the upper flange portion 35.

[0072] The outer concavo-convex portion 16 is also provided on the outer facing surface 10b that defines the cavity 53. The inner concavo-convex portion 26 is also provided on the inner facing surface 20b that defines the cavity 53. While the foamed beads 30A are being heated, the foamed beads 30A enter the concave portions of the outer concavo-convex portion 16 and the concave portions of the inner concavo-convex portion 26 due to expansion.

[0073] Note that the concave portion of the outer concavo-convex portion 16 on the outer facing surface 10b can be defined as the portion where the concave portions 16b are actually formed within the region where a plurality of concave portions 16b are arranged on the outer facing surface 10b. When a convex portion is actually formed on the outer facing surface 10b, the concave portion of the outer facing surface 10b can be defined as the portion where the convex portion is not actually formed. The concave portion of the inner concavo-convex portion 26 on the inner facing surface 20b can be defined as the portion where the concave portions 26b are actually formed within the region where a plurality of concave portions 26b are arranged on the inner facing surface 20b. When a convex portion is actually formed on the inner facing surface 20b, the concave portion of the inner facing surface 20b can be defined as the portion where the convex portion is not actually formed.

[0074] Figures 10A and 10B are explanatory diagrams of the process of opening the mold 50 (step S7) and the process of demolding (step S8).

[0075] By relatively displacing the first mold 51 and the second mold 52, the state of the mold 50 is switched from the mold-closed state to the mold-open state. The composite structure 100 may remain in the first mold 51 in a state of being fitted inside the mold recess 51A (see Figure 10A). The composite structure 100 may also remain in the mold in a state of being externally fitted to the mold protrusion 52A (see Figure 10B).

[0076] Referring to Figure 10A, when the composite structure 100 remains in the first mold 51, due to the expansion of the foam 30, the outer plate member 10 is pressed against the inner surface of the mold recess 51A. The composite structure 100 is taken out in the direction from the first mold 51 toward the second mold 52 (upward in the drawing paper surface). At this time, the outer surface of the outer peripheral plate portion 12 is a sliding surface as described above, and slides upward in contact with the inner surface of the mold recess 51A.

[0077] Referring to FIG. 10B, when the composite structure 100 remains in the second mold 52, due to the expansion of the foam 30, the inner plate member 20 is pressed against the outer surface of the mold convex portion 52A. The composite structure 100 is taken out in the direction from the second mold 52 toward the first mold 51 (downward in the drawing plane). At this time, the inner surface of the inner peripheral plate portion 22 is a sliding surface as described above, and slides downward in contact with the inner surface of the mold convex portion 52A.

[0078] In the example shown in FIG. 10A, the inner surface of the inner peripheral plate portion 22 does not slide with respect to the mold 50 during mold release, and in the example shown in FIG. 10B, the outer surface of the outer peripheral plate portion 12 does not slide with respect to the mold 50 during mold release. However, in view of the fact that these surfaces may slide with respect to the mold 50 depending on the situation, they are collectively referred to as sliding surfaces.

[0079] In the composite structure 100 according to the present embodiment, the outer plate member 10 has outer concavo-convex portions 16 provided on the outer surface 10a, and the inner plate member 20 has inner concavo-convex portions 26 provided on the inner surface 20a.

[0080] In the example shown in FIG. 10A, due to the presence of the outer concavo-convex portions 16, the outer surface 10a contacts the inner surface of the mold concave portion 51A at the convex portion, while being separated from the inner surface of the mold concave portion 51A at the concave portion. Since the contact area of the outer surface 10a with the inner surface of the mold concave portion 51A becomes smaller, the contact resistance also becomes smaller accordingly. Therefore, mold release can be facilitated. In particular, the outer concavo-convex portions 16 are provided on the sliding surface of the outer surface 10a. For this reason, the effect of facilitating mold release can be easily obtained.

[0081] The convex portions 16a are hemispherical, and therefore, the top portions of the respective convex portions 16a are dot-shaped, and the respective convex portions 16a are in almost point contact with the inner surface of the mold concave portion 51A. The contact area is greatly reduced, and mold release is further facilitated.

[0082] The same applies to the example shown in FIG. 10B. Due to the presence of the inner concavo-convex portions 26, the inner surface 20a contacts the outer surface of the mold convex portion 52A at the convex portion, while being separated from the outer surface of the mold convex portion 52A at the concave portion. Since the contact area of the inner surface 20a with the outer surface of the mold convex portion 52A becomes smaller, the contact resistance also becomes smaller accordingly. Therefore, demolding can be facilitated. In particular, the inner concavo-convex portions 26 are provided on the sliding surface of the inner surface 20a. For this reason, the effect of facilitating demolding can be easily obtained.

[0083] The convex portions 26a are hemispherical, and thus the top portions of the respective convex portions 26a are point-shaped, and each convex portion 26a is in almost point contact with the outer surface of the mold convex portion 52A. The contact area is greatly reduced, and demolding is further facilitated.

[0084] The outer concavo-convex portions 16 are also provided on the outer opposing surface 10b on the side opposite to the outer surface 10a in the plate thickness direction of the outer plate member 10. The inner concavo-convex portions 26 are also provided on the inner opposing surface 20b on the side opposite to the inner surface 20a in the plate thickness direction of the inner plate member 20. The foam body 30 is interposed between the outer opposing surface 10b and the inner opposing surface 20b, and the foam body 30 is engaged with the outer concavo-convex portions 16 and the inner concavo-convex portions 26. The foam body 30 meshes with the outer plate member 10 and the inner plate member 20 at the outer concavo-convex portions 16 and the inner concavo-convex portions 26 respectively, and the relative movement between the outer plate member 10 and the foam body 30 and the relative movement between the inner plate member 20 and the foam body 30 are prevented. Thereby, the three components of the outer plate member 10, the inner plate member 20, and the foam body 30 are integrated without separating from each other, and the bonding strength of the foam body 30 to the outer plate member 10 and the inner plate member 20 is improved. Even if no adhesive is used, the three components of the outer plate member 10, the foam body 30, and the inner plate member 20 can be maintained in a state of being firmly bonded to each other.

[0085] The outer concavo-convex portions 16 and the inner concavo-convex portions 26 are formed by arranging a plurality of convex portions 16a, 26a or concave portions 16b, 26b. For this formation, press working such as embossing is employed. The outer concavo-convex portions 16 can be easily provided on both sides of the outer plate material 10. The inner concavo-convex portions 26 can be easily provided on both sides of the inner plate material 20. Also, in the process of forming the blanks 10A, 20A, the outer concavo-convex portions 16 and the inner concavo-convex portions 26 can be provided simply, and the production efficiency of the outer plate material 10 and the inner plate material 20 is improved. For example, by using transfer pressing, the blanks 10A, 20A having the outer concavo-convex portions 16 and the inner concavo-convex portions 26 can be produced efficiently.

[0086] The composite structure 100 according to the present embodiment includes a pair of first side plates and a pair of second side plates, and these side plates constitute the peripheral plate 2 of the box body. Thereby, a box-shaped composite structure 100 with facilitated mold release can be provided. The composite structure 100 is composed of a three-layer structure in which metal plates are provided on both sides of a foaming material, and is excellent in robustness and heat insulation. A structure suitable for transporting goods that require temperature management can be produced efficiently.

[0087] Although the embodiments have been described so far, the above configuration can be appropriately changed within the scope of the gist of the present invention.

[0088] The composite structure 100 may be of a channel type. In that case, the pair of second side plates are omitted, and the composite structure 100 mainly includes three plates, namely, a bottom plate and a pair of side plates. Also in this case, similar to the box type, facilitated mold release and improved joining strength can be achieved.

[0089] For the purpose of achieving facilitated mold release, the outer concavo-convex portion 16 may be omitted from the outer facing surface 10b. The same applies to the inner concavo-convex portion 26.

[0090] In the above embodiment, the outer concavo-convex portion 16 is provided on the entire sliding surface, but this is an example. The outer concavo-convex portion 16 may be provided only on a part of the sliding surface. The same applies to the inner concavo-convex portion 26.

[0091] In the above-described embodiment, as shown in FIG. 5B, the outer concavo-convex portion 16 is configured by arranging a plurality of convex portions 16a (or concave portions 16b) having the same shape as each other, but this is only an example. As shown in FIG. 5C, the plurality of convex portions 16a constituting the outer concavo-convex portion 16a include a plurality of first convex portions 16a1 having a first protrusion height and a plurality of second convex portions 16a2 having a second protrusion height lower than the first protrusion height, and these first convex portions 16a1 and second convex portions 16a2 may be formed on the outer surface 10a. In that case, the plurality of concave portions 16b formed on the outer opposing surface 10b include a plurality of first concave portions 16b1 having a first depth corresponding to the first protrusion height and a plurality of second concave portions 16b2 having a second depth corresponding to the second protrusion height. The foam 30 can enter both the first concave portion 16b1 and the second concave portion 16b2. The first convex portion 16a1 slides with the mold 50, but the second convex portion 16a2 can be separated from the mold 50. Therefore, while maintaining a high bonding strength of the foam 30 to the outer plate member 10, the contact area of the outer plate member 10 with the mold 50 can be reduced, making demolding even easier. As shown in FIG. 5D, the plate portion (for example, the first outer side plate portion 13) constituting the outer plate member 10 is formed of a corrugated plate, and thereby the outer concavo-convex portion 16 may be provided on both sides of the plate portion. When the wave is in a sine curve shape, the convex portion 16a makes point contact or line contact with the mold 50, facilitating demolding. The same applies to the inner concavo-convex portion 26, and it can be changed in the same manner as that shown in FIG. 6B to that shown in FIG. 5C or FIG. 5D.

[0092] The present disclosure may include the following aspects. (Aspect 1) A composite structure including a bottom plate and a pair of side plates standing upright from the edges of the bottom plate, an outer plate member formed of metal, having an outer bottom plate portion constituting the bottom plate, an outer side plate portion constituting the pair of side plates, an outer surface of the outer bottom plate portion and the outer side plate portion, and an outer opposing surface on the opposite side thereof, and an inner plate member formed of metal, having an inner bottom plate portion constituting the bottom plate, an inner side plate portion constituting the pair of side plates, an inner surface of the inner bottom plate portion and the inner side plate portion, and an inner opposing surface on the opposite side thereof. Formed of a foaming material and having a foam filled between the outer facing surface and the inner facing surface, comprising, wherein the outer plate member has outer concavo-convex portions provided on the outer surface, and the inner plate member has inner concavo-convex portions provided on the inner surface, a composite structure. (Aspect 2) wherein the outer concavo-convex portions are provided on the outer facing surface, and the inner concavo-convex portions are provided on the inner facing surface, and the foam is engaged with the outer concavo-convex portions and the inner concavo-convex portions, the composite structure according to Aspect 1. (Aspect 3) wherein the outer concavo-convex portions and the inner concavo-convex portions are formed by arranging a plurality of concave portions or a plurality of convex portions, the composite structure according to Aspect 2. (Aspect 4) further comprising a pair of second side plates erected from the edge of the bottom plate, wherein the pair of side plates and the pair of second side plates constitute the peripheral plate of the box body, the composite structure according to any one of Aspects 1 to 3. (Aspect 5) A method for manufacturing a composite structure including a bottom plate and a pair of side plates erected from the edge of the bottom plate, comprising: forming a metal outer plate member having an outer bottom plate portion constituting the bottom plate, an outer side plate portion constituting the pair of side plates, an outer surface of the outer bottom plate portion and the outer side plate portion, and an outer facing surface on the opposite side thereof; forming a metal inner plate member having an inner bottom plate portion constituting the bottom plate, an inner side plate portion constituting the pair of side plates, an inner surface of the inner bottom plate portion and the inner side plate portion, and an inner facing surface on the opposite side thereof; a step of fitting the outer plate member into the mold recess and fitting the inner plate member onto the mold protrusion when a mold including a first mold having a mold recess and a second mold having a mold protrusion is in an open mold state where the mold protrusion has retreated from the mold recess; a step of closing the mold to a closed mold state where the mold protrusion enters the mold recess; a step of filling a foaming material into a cavity formed between the outer facing surface and the inner facing surface. A step of heating the foaming material and forming a foam between the outer plate material and the inner plate material; A step of opening the mold and taking out the composite structure from the mold; comprising In the step of forming the outer plate material, outer concavo-convex portions are provided on the outer surface, and in the step of forming the inner plate material, inner concavo-convex portions are provided on the inner surface. A method for manufacturing a composite structure. (Aspect 6) The outer concavo-convex portions are provided on the outer opposing surface, and the inner concavo-convex portions are provided on the inner opposing surface. In the step of heating the foaming material, the foam enters and engages with the outer concavo-convex portions and the inner concavo-convex portions. The method for manufacturing a composite structure according to Aspect 5. (Aspect 7) The outer concavo-convex portions and the inner concavo-convex portions are provided on the sliding surface with the mold among the outer surface and the inner surface. The method for manufacturing a composite structure according to Aspect 5 or 6. (Aspect 8) The step of forming the outer plate material includes a step of forming a flat blank having the outer bottom plate portion and the outer side plate portion in a developed state, and a step of performing bending on the blank so that the outer side plate portion stands up from the outer bottom plate portion. The outer concavo-convex portions are provided on the blank before the step of performing the bending. The method for manufacturing a composite structure according to any one of Aspects 5 to 7.

Explanation of Signs

[0093] 1 Bottom plate 2 Peripheral plate 3 First side plate 4 Second side plate 5 Flange 6 Internal space 10 Outer plate material 10A Blank 10a Outer surface 10b Outer opposing surface 11 Outer bottom plate portion 12 Outer peripheral plate part 13 First outer side plate part 14 Second outer side plate part 15 Lower flange part 16 Outer concavo-convex part 16a Convex part 16a1 First convex part 16a2 Second convex part 16b Concave part 16b1 First concave part 16b2 Second concave part 20 Inner plate material 20A Blank 20a Inner surface 20b Inner opposing surface 21 Inner bottom plate part 22 Inner peripheral plate part 23 First inner side plate part 24 Second inner side plate part 26 Inner concavo-convex part 26a Convex part 26b Concave part 30 Foam 30A Foam beads 30a Outer surface 30b Inner surface 31 Middle bottom plate part 32 Middle peripheral plate part 33 First middle side plate part 34 Second middle side plate part 35 Upper flange part 50 Mold 51 First mold 51A Mold concave part 51a First main body part 51b Shoulder part 52 Second mold 52A Mold convex part 52a Second main body part 52b Flange part 53 Cavity 54 Bead port 55 Steam port 100 Composite structure

Claims

1. A composite structure comprising a bottom plate and a pair of side plates erected from the edges of the bottom plate, an outer plate material having an outer bottom plate portion constituting the bottom plate, an outer side plate portion constituting the pair of side plates, outer surfaces of the outer bottom plate portion and the outer side plate portion, and an outer opposing surface on the opposite side thereof, and formed of metal, an inner plate material having an inner bottom plate portion constituting the bottom plate, an inner side plate portion constituting the pair of side plates, inner surfaces of the inner bottom plate portion and the inner side plate portion, and an inner opposing surface on the opposite side thereof, and formed of metal, a foam body formed of a foaming material and filled between the outer opposing surface and the inner opposing surface, and the outer plate material has outer concavo-convex portions provided on the outer surface, and the inner plate material has inner concavo-convex portions provided on the inner surface, composite structure.

2. the outer concavo-convex portions are provided on the outer opposing surface, the inner concavo-convex portions are provided on the inner opposing surface, and the foam body is engaged with the outer concavo-convex portions and the inner concavo-convex portions, The composite structure according to claim 1.

3. the outer concavo-convex portions and the inner concavo-convex portions are formed by arranging a plurality of concave portions or a plurality of convex portions, The composite structure according to claim 2.

4. further comprising a pair of second side plates erected from the edges of the bottom plate, and the pair of side plates and the pair of second side plates constitute a peripheral plate of a box body, The composite structure according to any one of claims 1 to 3.

5. A method for manufacturing a composite structure comprising a bottom plate and a pair of side plates erected from the edges of the bottom plate, a step of forming an outer plate material having an outer bottom plate portion constituting the bottom plate, an outer side plate portion constituting the pair of side plates, outer surfaces of the outer bottom plate portion and the outer side plate portion, and an outer opposing surface on the opposite side thereof, by metal, A step of forming an inner plate material having an inner bottom plate portion constituting the bottom plate, inner side plate portions constituting the pair of side plates, inner surfaces of the inner bottom plate portion and the inner side plate portions, and inner opposing surfaces on the opposite side thereof with metal; A step of fitting the outer plate material into the mold recess and fitting the inner plate material onto the mold projection when a mold including a first mold having a mold recess and a second mold having a mold projection is in an open mold state where the mold projection has retreated from the mold recess; A step of bringing the mold into a closed mold state where the mold projection enters the mold recess; A step of filling a foaming material into a cavity formed between the outer opposing surface and the inner opposing surface; A step of heating the foaming material to form a foam between the outer plate material and the inner plate material; A step of opening the mold and taking out the composite structure from the mold; comprising; In the step of forming the outer plate material, outer concavo-convex portions are provided on the outer surface, and in the step of forming the inner plate material, inner concavo-convex portions are provided on the inner surface; A method for manufacturing a composite structure.

6. The outer concavo-convex portions are provided on the outer opposing surface, and the inner concavo-convex portions are provided on the inner opposing surface, In the step of heating the foaming material, the foam enters and engages with the outer concavo-convex portions and the inner concavo-convex portions; The method for manufacturing a composite structure according to claim 5.

7. The outer concavo-convex portions and the inner concavo-convex portions are provided on a sliding surface with the mold among the outer surface and the inner surface; The method for manufacturing a composite structure according to claim 5 or 6.

8. The step of forming the outer plate material includes a step of forming a flat blank having the outer bottom plate portion and the outer side plate portion in a developed state, and a step of bending the blank so that the outer side plate portion stands upright from the outer bottom plate portion, The outer concavo-convex portions are provided on the blank before the step of performing the bending process. The method for manufacturing a composite structure according to claim 5 or 6.

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