JP2010247448A - Molding and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding which is excellent in appearance and strength and includes a honeycomb structure which can stand stress during bending and a method for producing the molding. <P>SOLUTION: As regards the molding A, because a bent part M by bending is formed in a structure having a core layer in which a sheet material prepared by molding a plastic sheet in a prescribed shape is folded and molded so that a plurality of polygonal pillarlike or cylindrical cells S are set in parallel and a skin layers which are arranged on the upper and lower sides of the core layer, a joining part existing in the core layer can hardly be peeled off by the existence of the skin layer. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a molded product formed by bending a structure and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, for example, a honeycomb structure is known as a plate-like structure in which a plurality of cells each having a polygonal column shape or a columnar shape are arranged in parallel. As a method for manufacturing a honeycomb structure from one sheet, for example, a manufacturing method described in Patent Document 1 is known.

  In the manufacturing method of Patent Document 1, after forming a sheet material by providing a plurality of bulged portions having a predetermined shape with respect to a plastic sheet, the sheet material is folded at a plurality of fold lines, and the parts that come into contact with each other A honeycomb structure is formed by bonding. Specifically, by folding one bulging portion, one prismatic partition body having a plurality of cells arranged in parallel in the fold line direction is formed, and the partition body is orthogonal to the fold line direction. A plurality of them are arranged in parallel. And a plate-shaped honeycomb structure is formed by joining adjacent division bodies mutually.

  By the way, the honeycomb structure is not only used as a plate material, but may be used as a molded product having a three-dimensional shape after being subjected to bending. Examples of the molded product subjected to such bending include members (for example, a bottom wall portion) constituting a pallet box as shown in FIG. 6 (see Patent Document 2).

Special table 2002-531287 gazette JP 2004-010129 A

  However, in the honeycomb structure of Patent Document 1, the adjacent partition bodies are joined to each other with the entire surface excluding the upper wall portion or the lower wall portion as a joining surface. Therefore, in the molded product obtained by bending the structure of Patent Document 1, the joint portion (joint surface) between the compartments is peeled off without being able to withstand the bending stress at the time of bending, and the molded product A tear may form on the surface. Such a tear becomes a factor of deteriorating the quality of the molded product in terms of appearance and strength of the molded product.

  The present invention has been made in view of such conventional circumstances, and an object thereof is to provide a molded article having excellent appearance and strength and a method for producing the same.

  In order to achieve the above object, the molded product according to claim 1, wherein a sheet material formed by molding a single sheet having plasticity into a predetermined shape includes a plurality of cells each having a polygonal column shape or a cylindrical shape. A bent portion formed by bending is formed in a structure having a core layer that is folded so as to be juxtaposed and skin layers disposed on both upper and lower surfaces of the core layer.

  According to the above configuration, since the skin layers are provided on both the upper and lower surfaces of the core layer, the strength thereof is increased as compared with a molded product in which a bent body is formed by bending a structure including only the core layer. . In addition, when bending stress is applied that causes the bonding portion existing in the core layer to be peeled off during bending, the presence of the skin layers on both the upper and lower surfaces of the core layer makes it difficult to peel off the bonding portion. By pulling, it is possible to suppress the formation of tears on the surface of the molded product.

  According to a second aspect of the present invention, in the invention according to the first aspect, in the core layer of the structure, one end surface of the cell is blocked by an upper wall or a lower wall of a two-layer structure. The other end face is closed by a lower wall or an upper wall of a single layer structure, and an opening is formed in the upper wall or the lower wall closing the one end face of the cell.

  According to the above configuration, on the upper wall and the lower wall of the core layer of the structure, a portion formed by two layers (one end surface of the cell) and a portion formed by one layer (the other end surface of the cell) Then, a portion (opening) where the upper wall and the lower wall do not exist is formed in cell units. When the skin layer is included, the first, second, and third layer portions are formed on the upper and lower surfaces of the structure in cell units. In a molded product obtained by bending such a structure, the portion of one layer allows positive deformation while allowing deformation, and the portion of three layers does not allow deformation and functions to maintain the cell structure. . The two-layer portion plays an intermediate role between the one-layer portion and the three-layer portion.

  Thus, by providing a portion that positively allows deformation in cell units and a portion that does not allow deformation and maintains the cell structure, the cell structure can be obtained even in the state of a bent product. It can be maintained more reliably. Thereby, while being able to obtain the molded product which has a smoother curved shape with few uneven | corrugated shapes, the intensity | strength of a molded product can be raised.

  The molded product according to claim 3 is the invention according to claim 1 or 2, wherein the core layer of the structure is formed with a communication portion that communicates between the adjacent cells. Features.

  Generally, bending of a structure is performed by fitting the structure in a heated state. Therefore, when each cell of the structure is completely sealed individually, the air in the cell may thermally expand and the internal pressure in the cell may be excessively increased. In such a state, if the molded product is taken out from the mold, the mold will not be pressed, so the cell will be deformed into an unexpected shape by the internal pressure in the cell (especially, the upper wall thinly stretched by bending) And the lower wall portion is deformed to swell). Such cell deformation appears as a fine protruding portion on the surface of the molded product obtained by bending the structure, which causes a deterioration in the quality of the molded product.

  With respect to such a problem, according to the above configuration, since the air in the cell in a state where the internal pressure is increased flows to another cell through the communication portion, the internal pressure in the cell due to the thermal expansion of the air in the cell. Can be distributed over multiple cells. Thereby, an excessive increase in the internal pressure in the cell can be suppressed, and an unexpected deformation of the cell caused by an excessive increase in the internal pressure can be suppressed.

  The method for producing a molded product according to claim 4 is a sheet material in which a planar region and a bulging region having a band shape are alternately arranged in the width direction, and the bulging region is orthogonal to the width direction. A first bulging portion extending in the direction and having a cross-sectional shape in the same direction forming a downward groove shape, and extending in the width direction and having a polygonal cross-sectional shape in the same direction. A forming step of forming a sheet material having a plurality of second bulging portions having a shape or a semicircular shape from one sheet having plasticity, and the boundary between the planar region and the bulging region. A plurality of cylinders that are sectioned and formed by the second bulge portion by folding the line and folding the boundary line between the upper surface and the side surface of the first bulge portion in the bulge region. Folds to form a core layer with standing cells An opening is formed between the pair of overlapping portions on one end surface of the cell closed by a pair of overlapping portions formed by the folding step and the planar region and the end surface of the second bulging portion. An opening forming step; a bonding step of bonding a skin layer to both upper and lower surfaces of the core layer to form a structure; and a processing step of bending the structure to form a bent portion. .

  According to a fifth aspect of the present invention, there is provided the method for manufacturing a molded product according to the fourth aspect, wherein the opening forming step heats the pair of overlapping portions by heating the core layer, thereby opening the opening. It is the process of forming.

  According to the method for manufacturing a molded product according to claims 4 and 5, the molded product according to claims 1 and 2 can be easily manufactured.

  According to the molded article of the present invention, its appearance and strength can be increased. Moreover, according to the manufacturing method of this invention, the molded article excellent in the external appearance and intensity | strength can be provided.

The perspective view of the molded article of this embodiment. (A) is a perspective view of the structure, (b) is a cross-sectional view taken along line α-α in (a), and (c) is a cross-sectional view taken along line β-β in (a). (A) is a perspective view of a sheet material, (b) is a perspective view showing a state in the middle of folding the sheet material, (c) is a perspective view showing a state in which the sheet material is folded. The schematic diagram which shows an example of a manufacturing apparatus. The perspective view which shows the side cover of the seat seat of the vehicle as a molded article. The perspective view which shows the pallet box as a molded article.

Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings.
As shown in FIGS. 2 (a) to 2 (c), a structure 1 for forming a molded article of this embodiment includes a core layer 2 that forms a honeycomb structure in which hexagonal columnar cells S are arranged side by side. And skin layers 3 and 4 bonded to the upper and lower surfaces of the core layer 2.

  As shown in FIGS. 2B and 2C, the core layer 2 is formed by, for example, folding a single sheet material formed by molding a sheet made of a thermoplastic resin such as polypropylene into a predetermined shape. The core layer 2 is composed of an upper wall 21 and a lower wall 22, and an intermediate wall 23 that is erected between the upper wall 21 and the lower wall 22 and juxtaposes a hexagonal tubular portion, The upper wall 21, the lower wall 22, and the intermediate wall 23 define hexagonal columnar cells S in the core layer 2.

  The cells S partitioned and formed in the core layer 2 include first cells S1 and second cells S2 having different configurations. As shown in FIG. 2 (b), the upper end of the first cell S1 is closed by the upper wall 21 of the two-layer structure, and the lower end is closed by the lower wall 22 of the one-layer structure. The layers of the upper wall 21 of the two-layer structure are joined to each other. And the opening part 24 is formed in the center part of the upper wall 21 in the upper end of 1st cell S1. The opening 24 is formed along one diagonal passing through the center on the end face of the first cell S1 having a hexagonal shape, and the shape thereof is substantially elliptical (see FIG. 2A). .

  On the other hand, as shown in FIG. 2C, the upper end of the second cell S2 is closed by the upper wall 21 of the one-layer structure, and the lower end is closed by the lower wall 22 of the two-layer structure. The layers of the lower wall 22 of this two-layer structure are joined together. And the opening part 24 similar to the opening part 24 provided in 1st cell S1 is formed in the center part of the lower wall 22 in the lower end of 2nd cell S2.

  As shown in FIG. 2A, the first cell S1 and the second cell S2 are arranged so that the first cells or the second cells S2 are adjacent to each other to form a column in the X direction. In the Y direction orthogonal to the X direction, the columns of the first cells S1 and the columns of the second cells S2 are alternately arranged.

  As shown in FIGS. 2B and 2C, the adjacent first cells S <b> 1 and the adjacent second cells S <b> 2 are formed perpendicular to the upper wall 21 and the lower wall 22. Are defined by an intermediate wall 23 having a two-layer structure. Since the intermediate wall 23 is formed perpendicular to the upper wall 21 and the lower wall 22, the structure 1 is strong against the force in the thickness direction of the structure 1, and the compressive strength is increased. Furthermore, since the intermediate wall 23 has a two-layer structure, the compressive strength of the structure 1 is further increased.

  The interlayer of the intermediate wall 23 having the two-layer structure is formed so as to be separated from each other only by contacting each other. Therefore, when the internal pressure in the cell S is increased due to preheating when bending is performed, the intermediate wall 23 is expanded by the internal pressure to form a communication portion 23a between the layers (FIG. (Refer to the broken line portions of 2 (b) and (c).) The communication portion 23a communicates the first cells S1 adjacent to each other in the Y direction or the second cells S2.

  The skin layers 3 and 4 are made of, for example, a sheet made of thermoplastic resin such as polypropylene, and are joined to the upper surface of the upper wall 21 and the lower surface of the lower wall 22 of the core layer 2, respectively. In addition, from the viewpoint that the core layer 2 and the skin layers 3, 4 can be easily joined by thermal welding, the sheet constituting the skin layers 3, 4 is made of the same material as the sheet constituting the sheet material of the core layer 2. It is preferable to use a sheet.

  2B and 2C, the upper surface of the structure 1 is composed of the upper wall 21 of the core layer 2 and the skin layer 3, and the lower surface of the structure 1 is below the core layer. The wall 22 and the skin layer 4 are included. For this reason, the upper surface of the structure 1 is formed of the one-layer portion L1 formed of only the skin layer 3 and corresponding to the opening 24, the upper wall 21 of the one-layer structure, and the skin layer 3. A two-layer portion L2 and a three-layer portion L3 composed of the upper wall 21 and the skin layer 3 are provided.

  The first layer portion L1, the second layer portion L2, and the third layer portion L3 are regularly arranged on the upper surface of the structure 1 corresponding to the arrangement positions of the first cells S1 and the second cells S2. Specifically, the first layer portion L1 and the third layer portion L3 are arranged at positions corresponding to the columns of the first cells S1, and the two layer portion L2 is arranged at a position corresponding to the columns of the second cells S2. . The three-layer portion L3 is disposed so as to surround the first-layer portion L1, and the first-layer portions L1 are disposed so as not to be continuous with each other. When viewed in cell units, the one-layer portion L1 is disposed at a position corresponding to the central portion of the end surface of the first cell S1, and the three-layer portion L3 is disposed at a position corresponding to the peripheral portion of the end surface of the first cell S1. Has been.

  Further, similarly to the upper surface, the first layer portion L1, the second layer portion L2, and the third layer portion L3 are also formed on the lower surface of the structure 1. Then, on the lower surface of the structure 1, the two-layer portion L2 is disposed at the portion that was the first-layer portion L1 and the three-layer portion L3 on the upper surface, and the one-layer portion L1 at the portion that was the two-layer portion L2 on the upper surface. And the three-layer part L3 is arrange | positioned.

  FIG. 1 shows a molded product A of the present embodiment. The molded product A is obtained by bending the structure 1, and the molded product A is provided with a bending portion M formed by bending. As shown in FIG. 1, the shape of the surface of the bent portion M is greatly deformed in the order of the first layer portion L1, the second layer portion L2, and the third layer portion L3, compared to the surface of the flat portion. Specifically, the first layer portion L1 and the second layer portion L2 are positively allowed to be deformed to greatly increase their areas. On the other hand, the three-layer portion L3 is positioned so as to gather at the periphery of the end surface of the cell S without increasing the area. By providing the first layer portion L1 and the second layer portion L2 that positively allow deformation in this way, the curved surface shape of the bent portion M becomes smooth. Moreover, the cell skeleton is reinforced by the three-layer portion L3 gathering at the periphery of the end face of the cell, contributing to the maintenance of the cell structure. Thereby, the bending part M of the molded product A of this embodiment has a smooth curved surface structure and high strength.

  Moreover, the structure 1 of this embodiment has the same structure in the upper surface and lower surface, and there is no directionality in both upper and lower surfaces. Therefore, the molded product A obtained from the structure 1 has substantially the same surface shape and strength in the bent portion M on both the convex surface side (outer surface side) and the concave surface side (inner surface side). Therefore, the molded product A of the present embodiment can be used as a molded product having the convex side of the bent part M as a surface, or can be used as a molded product having the concave side of the bent part M as a surface. The molded product A of the present embodiment includes, for example, side members of a vehicle seat as shown in FIG. 5 and each member (for example, a bottom wall portion) constituting a pallet box for article transportation as shown in FIG. ) Can be applied.

Next, the manufacturing method of the molded product A will be described.
The manufacturing method of the molded product A includes a forming step of forming the sheet material 100 from a sheet having plasticity, a folding step of forming the core layer 2 by folding the sheet material 100, and forming an opening 24 in the core layer 2. An opening forming step, a bonding step in which the skin layers 3 and 4 are bonded to both the upper and lower surfaces of the core layer 2 to form the structure 1, and a processing step in which the structure 1 is bent to provide the bent portion M. Including.

  In the molding step, the sheet material 100 is formed by thermoforming a single thermoplastic resin sheet into a predetermined shape. As shown in FIG. 3A, in the sheet material 100, a planar area 110 and a bulging area 120 having a band shape are alternately arranged in the width direction (X direction). In the bulging region 120, a first bulging portion 121 having a cross-section downward groove shape composed of an upper surface and a pair of side surfaces is formed over the entire extending direction (Y direction) of the bulging region 120. The angle formed between the upper surface and the side surface of the first bulge portion 121 is preferably 90 degrees. As a result, the cross-sectional shape of the first bulge portion 121 is a downward U-shape. Further, the width of the first bulging portion 121 (the length of the upper surface in the short direction) is equal to the width of the planar region 110, and the bulging height of the first bulging portion 121 (the length of the side surface in the short direction). ) Is set to be twice as long.

  Further, in the bulging region 120, a plurality of second bulging portions 122 having a trapezoidal shape obtained by dividing the regular hexagon by the longest diagonal line in the bulging region 120 are orthogonal to the first bulging portion 121. Is formed. The bulge height of the second bulge portion 122 is set to be equal to the bulge height of the first bulge portion 121. Further, the interval between the adjacent second bulging portions 122 is equal to the width of the upper surface of the second bulging portion 122.

  The first bulging portion 121 and the second bulging portion 122 are formed by partially bulging the sheet upward using the plasticity of the sheet. The sheet material 100 can be formed from a single sheet by a known forming method such as a vacuum forming method or a compression forming method.

  In the folding step, as shown in FIGS. 3A and 3B, the sheet material 100 is valley-folded at the boundary line P between the planar region 110 and the bulging region 120, and the first bulging portion 121 The mountain is folded at the boundary line Q between the upper surface and the side surface and compressed in the X direction. Then, the upper surface and the side surface of the first bulge portion 121 are folded and the end surface of the second bulge portion 122 and the planar region 110 are folded, thereby extending in one Y direction with respect to one bulge region 120. A prismatic partition 130 is formed (see FIG. 3C). The plate-shaped core layer 2 is formed by continuously forming such partition bodies 130 in the X direction.

  At this time, the upper wall 21 of the core layer 2 is formed by the upper surface and the side surface of the first bulging portion 121, and the lower wall 22 of the core layer 2 is formed by the end surface of the second bulging portion 122 and the planar region 110. It is formed. Further, the intermediate wall 23 is formed by the upper surface and the side surface of the second bulging portion 122. In addition, the upper surface and the side surface of the first bulging portion 121 in the upper wall 21 are folded to form a two-layer structure, and the end surface of the second bulging portion 122 in the lower wall 22 and the planar region 110 are folded and overlapped. The portions forming the layer structure are the overlapping portions 131 (see FIG. 3C).

  The hexagonal columnar region formed by folding the second bulging portion 122 is the second cell S2, and the hexagonal columnar region partitioned between a pair of adjacent partitions 130 is the first cell. S1. In the first cell S1, the upper end is closed by a pair of overlapping portions 131, and in the second cell S2, the lower end is closed by a pair of overlapping portions 131.

  In performing the folding process, it is preferable to heat and soften the sheet material 100. However, the folding process can be performed without performing the heating process.

  In the opening forming process, the upper surface and the lower surface of the core layer 2 are heated at a predetermined temperature while the folded state of the core layer 2 is maintained. Then, when the belt layer is pressed in the thickness direction of the core layer 2 (vertical direction in FIGS. 2B and 2C), the overlapping portion 131 having a two-layer structure is thermally welded and joined. At the same time, each overlapping portion 131 is thermally contracted, and a gap as an opening 24 is formed between the pair of overlapping portions 131 that define the upper end of the first cell S1 and the lower end of the second cell S2 (see FIG. 2). ). In the case where the sheet material 100 is heat-treated during the folding process, from the viewpoint of forming the opening 24 more easily, the heat treatment in the opening forming process is performed at the temperature during the heat-treating process during the folding process. It is preferable to carry out at a higher temperature. Moreover, it is performed on the condition that the intermediate wall 23 of the two-layer structure is not thermally bonded and joined while the overlapping portion 131 contracts.

  The joining step is a step of obtaining the structure 1 shown in FIG. 2 by joining the skin layers 3 and 4 to the upper surface and the lower surface of the core layer 2 obtained through the opening forming step, respectively. In the present embodiment, the same thermoplastic resin sheet as the thermoplastic resin constituting the core layer 2 is used as the skin layers 3 and 4. The skin layers 3 and 4 are bonded to the core layer 2 by being thermally welded to the core layer 2. In addition, when the sheet | seat of the same material is used for the sheet | seat which comprises the skin layers 3 and 4 and the sheet | seat material 100 which comprises the core layer 2, the skin layers 3 and 4 and the core layer 2 are joined by heat welding. be able to. Therefore, the joining process can be performed with a simple configuration as compared with the case where the skin layers 3 and 4 and the core layer 2 are joined using an adhesive.

  The subsequent processing step is a step of obtaining the molded product A by forming the bent portion M by subjecting the structure 1 to a softened state by performing a heat treatment and performing a bending process such as a press process. In the molded product A shown in FIG. 1, a hemispherical bent portion M is provided. The heating temperature in the processing step is set to the softening temperature of the sheets constituting the core layer 2 and the skin layers 3 and 4, and the core body 2 and the skin layers 3 and 4 are made to be in a softened state. Bending is performed in a welded (molten) state. Thereby, peeling of the joint part of the core layer 2 and the skin layers 3 and 4 at the time of a bending process and formation of a tear are suppressed.

  In the processing step, the internal pressure of the cell S of the molded product A is increased by the preheating of the heat treatment. At this time, due to the internal pressure in the cell S, the interlayer of the intermediate wall 23 having the two-layer structure is expanded to form a communication portion 23a (see FIGS. 2B and 2C). And the internal pressure in the cell S is disperse | distributed to the other cell S adjacent on both sides of the intermediate wall 23 via the communication part 23a. In the present embodiment, the sheet material 100 that forms the core layer 2 is formed of a thermoplastic resin. Therefore, when the resin shrinks during cooling after bending, each layer of the intermediate wall 23 in the expanded state may return to the original two-layer structure. In addition, the intermediate wall 23 often spreads to the left and right due to the bending force and the internal pressure in the cell S, so there is no directivity and no reduction in strength.

  FIG. 4 schematically shows an apparatus for continuously manufacturing the structure 1. In the apparatus shown in FIG. 4, the left side is the upstream side and the right side is the downstream side. The sheet roll 30 disposed on the upstream side is obtained by winding a sheet made of a thermoplastic resin that is a raw material of the core layer 2. A vacuum forming drum 31 is disposed on the downstream side of the sheet roll 30. The vacuum forming drum 31 is rotatably supported and can be heated to a predetermined temperature. Further, a cylindrical molding die is attached to the outer peripheral portion of the vacuum forming drum 31, and is configured to be able to be evacuated through a through-hole formed in the molding die (illustration shown). (Omitted). On the outer peripheral surface of the molding die, a concavo-convex shape similar to the concavo-convex shape composed of the planar region 110 and the bulging region 120 of the sheet material 100 is formed so that the X direction of the sheet material 100 is along the circumferential direction. ing.

  On the downstream side of the vacuum forming drum 31, a pair of upper and lower first conveyors 32 and a second conveyor 33 are sequentially arranged. The conveyance speed by the second conveyor 33 is set to be slower than the conveyance speed by the first conveyor 32. Further, the second conveyor 33 is provided with a heating device 33a for heating the temperature between the second conveyors 33 to a predetermined temperature.

  In addition, a pair of upper and lower third conveyors 34 is disposed on the downstream side of the second conveyor 33. The third conveyor 34 is provided with a heating device 34a for heating the temperature between the third conveyors 34 to a predetermined temperature. Note that the conveyance speed by the third conveyor 34 is set to be equal to the conveyance speed by the second conveyor 33. Further, in the vicinity of the carry-in port of the third conveyor 34, sheet rolls 35 and 36 each having a sheet made of a thermoplastic resin as a raw material for the skin layers 3 and 4 are disposed.

  Next, a mode in which the structure 1 is formed by the apparatus shown in FIG. 4 will be described. First, the sheet is fed out from the sheet roll 30 and supplied to the vacuum forming drum 31. And the predetermined uneven | corrugated shape is formed in a sheet | seat with the drum 31 for vacuum forming, and the sheet | seat material 100 is shape | molded (forming process). The formed sheet material 100 is conveyed downstream by the first conveyor 32 and the second conveyor 33 in a state where movement in the vertical direction is restricted. At this time, since the conveyance speed by the second conveyor 33 is set to be slower than the conveyance speed by the first conveyor 32, the sheet material 100 is conveyed from the first conveyor 32 to the second conveyor 33. In the process, the core layer 2 is formed by being compressed and folded in the downstream direction (folding step).

  Further, the formed core layer 2 is heated by the heating device 33 a of the second conveyor 33 and is pressed by the second conveyor 33. Thereby, the overlapping portion 131 of the core layer 2 is thermally welded and contracts to form the opening 24 in the core layer 2 (opening forming step). Then, the core layer 2 is conveyed to the third conveyor 34. When the core layer 2 is conveyed to the third conveyor 34, the skin layers 3 and 4 fed from the sheet rolls 35 and 36 are inserted between the upper and lower surfaces of the core layer 2 and the third conveyor 34. The The upper and lower surfaces of the skin layers 3, 4 and the core layer 2 are heated by the heating device 34 a of the third conveyor 34. By this heating, the skin layers 3 and 4 are thermally welded to the upper and lower surfaces of the core layer 2 to obtain the structure 1 (joining step).

  Thus, the plate-like structure 1 can be manufactured continuously. And the structure 1 carried out from the 3rd conveyor 34 is cut | disconnected by the magnitude | size according to a use, and becomes the molded article A through the process process which forms the bending part M. FIG.

Next, operational effects in the present embodiment will be described below.
(1) The molded product A of this embodiment includes a core layer 2 formed by folding a sheet material formed from a single sheet having plasticity so that a plurality of hexagonal columnar cells S are arranged side by side. A bent portion M is formed by bending on the structure 1 having the skin layers 3 and 4 disposed on the upper and lower surfaces of the core layer 2.

  Since the skin layers 3 and 4 are provided on the upper and lower surfaces of the core layer 2, the strength thereof is higher than that of a molded product obtained by forming a bent portion M by bending in a structure composed only of the core layer 2. Has been enhanced. In addition, when bending stress is applied in the direction of peeling the joint portion existing in the core layer 2 (particularly, the joint portion between the compartments 130) during the bending process, the skin layers 3, The presence of 4 makes it difficult for the joint portion to peel off. And it can suppress that a tear arises on the surface of a molded article resulting from peeling of the said junction part.

  (2) In the core layer 2, the upper end of the first cell S1 is closed by the upper wall 21 of the two-layer structure, and the lower end is closed by the lower wall 22 of the one-layer structure. Is formed with an opening 24. On the other hand, the upper end of the second cell S2 is closed by the upper wall 21 of the one-layer structure and the lower end is closed by the lower wall 22 of the two-layer structure, and an opening 24 is formed in the lower wall 22 of the two-layer structure. Has been.

  As a result, the upper and lower surfaces of the structure 1 include the skin layers 3 and 4 and include the one-layer portion L1 corresponding to the opening 24 and the two-layer portions L2 corresponding to the upper and lower walls of the one-layer structure. And a three-layer portion L3 corresponding to the upper wall and the lower wall of the two-layer structure are formed in cell units. In the molded product A obtained by forming the bent portion M by bending the structure 1, the first layer portion L1 is positively extended while allowing deformation, and the third layer portion L3 is not allowing deformation. , Function to maintain the structure of the cell S. The two-layer portion L2 plays an intermediate role between the first-layer portion L1 and the three-layer portion L3.

  Thus, by providing a portion that positively allows deformation in units of cells and a portion that does not allow deformation and maintains the cell structure, the cell structure can be further improved in the bent portion M whose shape is deformed. It can be reliably maintained. By maintaining the cell structure of each cell S in the bending part M, the curved surface shape of the bending part M can be made smooth and the strength of the bending part M can be increased.

  Further, in the present embodiment, a one-layer portion L1 that greatly deforms in units of cells and a three-layer portion L3 that hardly deforms are provided, and the three-layer portion L3 is positioned so as to surround substantially the entire periphery of the one-layer portion L1. It is provided to do. Thereby, it is possible to suppress unintended bulging portions, wrinkles, and the like from being formed in the bending portion M that is stretched and deformed, and to suppress a decrease in strength of the bending portion M. Moreover, the strength fall of the bending part M can be further suppressed by positioning the 2 layer part L2 adjacent to the 3 layer part L3.

  (3) The core layer 2 of the structure 1 is formed with a communication portion 23a that communicates between the first cells S1 and the second cells S2 adjacent in the Y direction. In general, bending of the structure 1 is performed by fitting the structure 1 into a mold in a heated state. Therefore, when each cell of the structure is completely sealed individually, the air in the cell may thermally expand and the internal pressure in the cell may be excessively increased. In such a state, when the molded product is taken out of the mold, the mold is not pressed by the mold, so that the cell S is deformed into an unexpected shape by the internal pressure in the cell (particularly, it is thinly stretched by bending). The upper wall 21 and the lower wall 22 may be deformed to swell). However, according to the above configuration, since the air in the cell S in the state where the internal pressure is increased flows to the other cell S through the communication portion 23a, the air in the cell S is thermally expanded. The increase in internal pressure can be distributed to a plurality of cells S. Thereby, an excessive increase in the internal pressure in the cell S can be suppressed, and an unexpected deformation of the cell S caused by an excessive increase in the internal pressure can be suppressed.

  (4) The intermediate wall 23 of the molded product of this embodiment is formed in a two-layer structure. The layers are formed so as to be separated only by contacting each other. Thereby, when the force which compresses to the thickness direction acts on a molded article excessively, the intermediate wall 23 can be in the state expanded so that each layer might space apart. In addition, the intermediate wall 23 that has been spread out tends to be restored to its original state due to the characteristics of the resin as the force is weakened. Since the intermediate wall 23 can allow deformation with respect to the force acting in the thickness direction of the molded product, the molded product exhibits excellent shock absorption (cushioning property) with respect to the force. That is, the intermediate wall 23 can function as an impact absorbing portion.

  (5) The method for manufacturing a molded product according to the present embodiment includes an opening forming step of forming the opening 24 between the pair of overlapping portions 131 on one end face of the cell S closed by the pair of overlapping portions 131. I have. By providing the opening forming step, in addition to the two-layer portion L2 and the three-layer portion L3, the one-layer portion L1 corresponding to the opening 24 is formed on the upper surface and the lower surface of the structure 1 in units of cells. Become. The molded product A obtained by providing the bent portion M to the structure 1 having the first layer portion L1, the second layer portion L2, and the third layer portion L3 is easily maintained in the bent portion M. The curved surface shape of the part M is smooth and the strength is high as a whole.

  (6) In the opening forming step in the method for manufacturing a molded article according to the present embodiment, the core layer 2 is heated to thermally contract the pair of overlapping portions 131 to form the opening 24. According to this configuration, the openings 24 can be formed in the plurality of cells S simultaneously and in a short time.

In addition, this embodiment can also be changed and embodied as follows.
As long as the sheet | seat which comprises the core layer 2 and the skin layers 3 and 4 has plasticity, what kind of material may be sufficient as it. For example, a sheet made of a fiber binding material, a paper sheet, or a metal sheet may be used. Moreover, the core layer 2 and the skin layers 3 and 4 may be comprised from the sheet | seat of a mutually different material.

  Furthermore, a sheet having molecular orientation such as a stretched sheet made of a synthetic resin may be used as a sheet constituting the skin layers 3 and 4. In such a case, it is preferable that the sheet orientation direction in the skin layers 3 and 4 is different from the direction (Y direction) in which the partition 130 extends in the core layer 2. When comprised in this way, the intensity | strength of the structure 1 (molded product A) with respect to the bending along a X direction can be raised compared with the case where the said both directions are arrange | equalized.

  In the molded product of the present embodiment, the hexagonal columnar cells S are defined in the core layer 2, but the shape of the cells S is not particularly limited, and examples thereof include a quadrangular columnar shape and an octagonal columnar shape. It may be a polygonal column shape or a cylindrical shape. At that time, the shapes of the first cell S1 and the second cell S2 may be different, or only one of the first cell S1 and the second cell S2 may be provided.

  In the molded product of this embodiment, the openings 24 are provided in all the cells S. However, the openings 24 may be provided only in specific cells S. For example, the opening 24 may be provided in only one of the first cell S1 and the second cell S2. Moreover, it is good also as a structure which does not provide the opening part 24. FIG.

The shape of the opening 24 is not particularly limited, and may be any shape such as a circular shape or a polygonal shape.
In the molded product of this embodiment, the communication portion 23a is provided so as to communicate between the first cells S1 adjacent to each other in the Y direction in FIG. 2 and between the second cells S2. Any cell S may be provided so as to communicate with each other. That is, you may provide the communication part 23a which connects between 1st cell S1 (2nd cell S2) adjacent to a X direction, or between 1st cell S1 and 2nd cell S2. Moreover, it is good also as a structure which provides the communication part 23a only in the specific cell S instead of providing the communication part 23a in all the cells S. FIG. In this case, it is preferable to provide the communication part 23a at least at a site where the bending stress acts (the bending part M and the cell S located in the peripheral part thereof). Furthermore, it is good also as a structure which does not provide the communication part 23a.

  In the molded product A shown in FIG. 1, only the bent portion M that swells upward with respect to the plane of the structure 1 is formed, but the bent portion M that swells upward and the bent portion M that swells downwardly are formed. Each may be a molded product A provided.

  In the present embodiment, the interlayer of the intermediate wall 23 having the two-layer structure is formed so as to be separated from each other only by contacting the entire surface. However, the communication portion 23a can be formed between the layers of the intermediate wall 23 having the two-layer structure. If so, a joint portion may be partially provided between the same layers. For example, the intermediate wall 23 may be configured such that both end portions in the stacking direction of the core layer 2 and the skin layers 3 and 4 are joined and a non-adhesive portion in which each layer can be separated is provided on the center side. The said structure can be formed by heating to such an extent that the both ends of the intermediate wall 23 soften at the time of the heat processing of the core layer 2 in a joining process, for example.

  In the molded product according to the present embodiment, when the internal pressure in the cell S increases, the two layers of the intermediate wall 23 are separated from each other to form the communication portion 23a. A groove, a gap, or the like as the communication portion 23a may be provided between the layers so that the cells S are always in a communication state.

  In the opening forming step in the method for manufacturing a molded article according to the present embodiment, the opening 24 is formed between the pair of overlapping portions 131 by heat-shrinking the pair of overlapping portions 131 by performing heat treatment. However, the opening forming process is not limited to this. For example, the opening forming step may be a step of drilling the opening 24 in the pair of overlapping portions 131.

  -In the opening formation process in the manufacturing method of the molded product of this embodiment, although the opening formation process and the joining process were performed separately, you may make it perform these simultaneously. That is, the formation of the opening 24 by thermal contraction of the pair of overlapping portions 131 and the thermal welding of the skin layers 3 and 4 to the core layer 2 may be performed simultaneously by a single heat treatment.

  In the joining step in the method for manufacturing a molded product according to the present embodiment, the skin layers 3 and 4 are joined to the core layer 2 by being thermally welded to the core layer 2. You may comprise so that it may join to the core layer 2. FIG. In this case, the sheet constituting the core layer 2 and the skin layers 3 and 4 is used to prevent the adhesive from becoming a liquefied state and peeling of the joint portion when the structure 1 is heat-treated in the subsequent processing step. It is preferable to use an adhesive having a higher liquefaction temperature than the softening temperature.

Next, a technical idea that can be grasped from the above embodiment and another example will be described.
A sheet material formed by molding a single sheet, in which strip-shaped planar regions and bulging regions are alternately arranged in the width direction, and in the bulging region in a direction perpendicular to the width direction A first bulging portion extending in the same direction and having a cross-sectional shape in the downward direction, and a first bulging portion that intersects the first bulging portion, extending in the width direction and having a polygonal cross-sectional shape in the same direction Alternatively, the sheet material having a plurality of second bulges that are semicircular is folded at the boundary line between the planar region and the bulge region, and the upper surface of the first bulge portion in the bulge region A molded product characterized in that a bent portion is formed by bending in a structure in which a skin layer is disposed on both upper and lower surfaces of a core layer formed by folding a boundary line between the side wall and a side surface.

  The core layer includes a plurality of cylindrical cells defined by the second bulging portion, and one end surface of the cell is formed from the planar region and the end surface of the second bulging portion. And the other end surface is closed by the upper surface of the first bulging portion, and an opening is formed between the pair of overlapping portions on one end surface of the cell. A molded product characterized by

  A core layer formed by folding a sheet material formed by molding a plastic sheet into a predetermined shape so that a plurality of cells having a polygonal cylindrical shape or a cylindrical shape are arranged in parallel, and the core And a skin layer disposed on both upper and lower surfaces of the layer.

  A sheet material in which flat areas and bulging areas forming a belt shape are alternately arranged in the width direction, and the bulging area extends in a direction perpendicular to the width direction and has a cross-sectional shape downward in the same direction. A first bulging portion having a groove shape, and a plurality of second bulging portions which intersect with the first bulging portion and extend in the width direction and have a polygonal shape or a semicircular cross-sectional shape in the same direction. The sheet material having a bulging portion is molded from a single sheet having plasticity, the sheet material is valley-folded at the boundary between the planar region and the bulging region, and the bulging region A core layer in which a plurality of cylindrical cells partitioned by the second bulge portion are erected is formed by folding the boundary line between the upper surface and the side surface of the first bulge portion in the mountain. Folding process, the planar region and the first An opening forming step of forming an opening between the pair of overlapping portions on one end surface of the cell blocked by the pair of overlapping portions formed from the end surfaces of the bulging portion; and upper and lower surfaces of the core layer And a bonding step of forming a structure by bonding the skin layer to the structure.

A ... molded product, M ... bent part, P, Q ... boundary line, S ... cell, S1 ... first cell, S2 ... second cell, L1 ... one layer part, L2 ... two layer part, L3 ... three layer part DESCRIPTION OF SYMBOLS 1 ... Structure, 2 ... Core layer, 3, 4 ... Skin layer, 21 ... Upper wall, 22 ... Lower wall, 24 ... Opening part, 100 ... Sheet material, 110 ... Plane area | region, 120 ... Swelling area | region, 121 ... 1st bulge part, 122 ... 2nd bulge part, 131 ... Overlapping part.

Claims (5)

A core layer formed by folding and molding a sheet material formed of a single plastic sheet into a predetermined shape so that a plurality of cells having a polygonal column shape or a columnar shape are arranged in parallel; A molded article characterized in that a bent part is formed by bending on a structure having skin layers arranged on both upper and lower surfaces. In the core layer of the structure, one end face of the cell is closed by an upper wall or a lower wall of a two-layer structure, and the other end face is closed by a lower wall or an upper wall of a single layer structure, The molded product according to claim 1, wherein an opening is formed in an upper wall or a lower wall that closes one end face. 3. The molded article according to claim 1, wherein the core layer of the structure is formed with a communication portion that communicates between the adjacent cells. A belt-shaped planar region and a bulging region are alternately arranged in the width direction, and the groove extends in the bulging region in a direction perpendicular to the width direction and has a downward cross-sectional shape in the same direction. A first bulging portion having a shape and a plurality of second bulgings formed so as to intersect the first bulging portion and extending in the width direction and having a cross-sectional shape in a polygonal shape or a semicircular shape in the same direction. Forming a sheet material having a portion from a single sheet having plasticity;
By folding the sheet material at the boundary line between the planar region and the bulging region and folding the boundary line between the upper surface and the side surface of the first bulging part in the bulging region. A folding step of forming a core layer in which a plurality of cells having a cylindrical shape defined by the second bulging portion are erected, and
An opening forming step of forming an opening between a pair of overlapping portions on one end surface of the cell closed by a pair of overlapping portions formed from the planar region and an end surface of the second bulging portion; ,
A bonding step in which a skin layer is bonded to both upper and lower surfaces of the core layer to form a structure;
And a processing step of forming the bent portion by bending the structure. The method for manufacturing a molded article according to claim 4, wherein the opening forming step is a step of heating the core layer to thermally contract the pair of overlapping portions to form the opening. .

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