Porous structure and method for manufacturing the porous structure

Abstract

To provide a porous structure capable of improving a degree of freedom in adjusting kinetic properties of a porous structure, and a manufacturing method of the porous structure.SOLUTION: A porous structure 1 of the present invention is composed of a flexible resin or rubber. The porous structure has a skeleton part 2 in its entirety. The skeleton part has a plurality of bone parts 2B and a plurality of binding parts 2J binding between end parts of the plurality of bone parts. The porous structure has a configuration in which the plurality of parts in the skeleton part interfere with each other when compressively deformed in a prescribed load input direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a porous structure and a method for producing a porous structure. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a porous structure having cushioning properties (for example, urethane foam) has been produced through a process of foaming by chemical reaction, for example, in a mold molding process. Meanwhile, in recent years, there have been proposals for porous structures that can be easily manufactured using a 3D printer to provide cushioning properties (for example, Patent Document 1 and Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] WO2019 / 235544 publication [Patent Document 2] WO2019 / 235547 publication Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the techniques of Patent Documents 1 and 2 described above, there is room for improvement in terms of the degree of freedom in adjusting the dynamic properties of the porous structure.

[0005] An object of the present invention is to provide a porous structure and a method for manufacturing a porous structure that can improve the degree of freedom in adjusting the dynamic properties of the porous structure. [Means for solving the problem]

[0006] The porous structure of the present invention comprises: A porous structure made of flexible resin or rubber, The porous structure has a skeleton throughout its entirety, The skeleton portion is A plurality of bones; a plurality of connecting portions each connecting an end portion of the plurality of bone portions to each other; Equipped with The porous structure is configured such that, when compressively deformed in a predetermined load input direction, a plurality of portions of the skeleton interfere with each other. According to the porous structure of the present invention, the degree of freedom in adjusting the dynamic properties of the porous structure can be improved.

[0007] In the porous structure of the present invention, At least one of the plurality of bone portions is a discontinuous bone portion including a first divided bone portion and a second divided bone portion, each of which is divided from the other. The porous structure may be configured such that the first divided bone portion and the second divided bone portion in the discontinuous bone portion rub against each other when the porous structure is compressively deformed in the predetermined load input direction. In this case, the degree of freedom in adjusting the dynamic properties of the porous structure can be improved.

[0008] In the porous structure of the present invention, In the discontinuous bone portion, The first split bone portion has a first side surface, The second split bone portion has a second side surface, The porous structure may be configured so that, when compressed and deformed in the specified load input direction, the first side surface of the first divided bone portion and the second side surface of the second divided bone portion in the discontinuous bone portion rub against each other. In this case, the degree of freedom in adjusting the dynamic properties of the porous structure can be improved.

[0009] In the porous structure of the present invention, At least one of the first divided bone portion and the second divided bone portion in the discontinuous bone portion may be strip-shaped. In this case, the degree of freedom in adjusting the dynamic properties of the porous structure can be improved.

[0010] In the porous structure of the present invention, At least one of the first side surface and the second side surface of the discontinuous bone portion may have a plurality of protrusions. In this case, the degree of freedom in adjusting the dynamic properties of the porous structure can be improved.

[0011] In the porous structure of the present invention, In the discontinuous bone portion, the second side surface may be configured to surround the first side surface along the circumferential direction of the first split bone portion when the porous structure is compressively deformed in the specified load input direction. In this case, the degree of freedom in adjusting the dynamic properties of the porous structure can be improved.

[0012] In the porous structure of the present invention, In the discontinuous bone portion, the first divided bone portion has a first end surface inclined with respect to a direction perpendicular to the extension direction of the first divided bone portion at an end portion in the extension direction of the first divided bone portion, The second divided bone portion has a second end surface at an end portion in an extension direction of the second divided bone portion, the second end surface being inclined with respect to a direction perpendicular to the extension direction of the second divided bone portion, the first end surface and the second end surface are substantially parallel to each other, The porous structure may be configured such that, when compressed and deformed in the specified load input direction, the first end surface of the first divided bone portion and the second end surface of the second divided bone portion in the discontinuous bone portion rub against each other. In this case, the degree of freedom in adjusting the dynamic properties of the porous structure can be improved.

[0013] In the porous structure of the present invention, An extension direction of the first divided bone portion and an extension direction of the second divided bone portion in the discontinuous bone portion may be non-parallel to each other. In this case, the degree of freedom in adjusting the dynamic properties of the porous structure can be improved.

[0014] In the porous structure of the present invention, the skeleton has a plurality of cell partitions that partition cell pores therein, Each of the cell partitions is composed of a plurality of the bone portions and a plurality of the joint portions, The porous structure may be configured such that, when the porous structure is compressively deformed in the predetermined load input direction, two or more of the plurality of cell partitions interfere with each other. In this case, the degree of freedom in adjusting the dynamic properties of the porous structure can be improved.

[0015] In the porous structure of the present invention, Preferably, the framework further comprises one or more bridge portions connecting the two or more cell compartments together. This allows the two or more cell partitions to be integrated together via the bridge portion.

[0016] In the porous structure of the present invention, the skeleton has a plurality of cell partitions that partition cell pores therein, Each of the cell partitions has a plurality of annular portions each configured in an annular shape, the plurality of annular portions constituting the cell partition are connected to each other such that imaginary planes defined by the respective inner circumferential side edges do not intersect with each other, Each of the annular portions is composed of a plurality of the bone portions and a plurality of the connection portions, Each of the virtual surfaces is substantially flat, It is preferable that the cell holes are defined by the plurality of annular portions and the plurality of imaginary surfaces defined by the plurality of annular portions, respectively. This can improve the cushioning properties of the porous structure.

[0017] In the porous structure of the present invention, the plurality of annular portions constituting the cell partition include one or more small annular portions and one or more large annular portions, Each of the small annular portions defines a small substantially flat imaginary surface by its inner peripheral edge portion, It is preferable that each of the large annular portions defines, by its inner peripheral edge, a large imaginary surface which is substantially flat and has an area larger than that of the small imaginary surface. This can improve the cushioning properties of the porous structure.

[0018] In the porous structure of the present invention, It is preferable that the small imaginary surface and the large imaginary surface have shapes different from each other. This can improve the cushioning properties of the porous structure.

[0019] In the porous structure of the present invention, It is preferable that each of the cell holes has a shape of approximately a Kelvin tetrahedron. This can improve the cushioning properties of the porous structure.

[0020] In the porous structure of the present invention, The porous structure is suitable for use as a cushioning material.

[0021] In the porous structure of the present invention, The porous structure is preferably formed by a 3D printer.

[0022] The method for producing a porous structure of the present invention comprises the steps of: The above porous structure is manufactured using a 3D printer. According to the method for producing a porous structure of the present invention, the degree of freedom in adjusting the dynamic properties of the porous structure can be improved. Effect of the Invention

[0023] According to the present invention, it is possible to provide a porous structure and a method for manufacturing a porous structure that can improve the degree of freedom in adjusting the dynamic properties of the porous structure. [Brief description of the drawings]

[0024] [Figure 1]FIG. 1 is a perspective view showing a part of a porous structure according to a first embodiment of the present invention in its natural state without compressive deformation. [Diagram 2] 2 is a perspective view showing a cell partition portion having no discontinuous bone portion in the porous structure of FIG. 1. FIG. [Diagram 3] 2 is a perspective view showing a cell partition having discontinuous bone portions in the porous structure of FIG. 1. FIG. [Figure 4] FIG. 4(a) is an oblique view showing a portion of the porous structure of FIG. 1 in its natural state without compressive deformation, and FIG. 4(b) is a drawing for explaining the discontinuous bone portion in the porous structure in the state of FIG. 4(a). [Diagram 5] FIG. 5(a) is an oblique view showing a portion of the porous structure of FIG. 1 in a state where it is compressed and deformed in a predetermined load input direction, and FIG. 5(b) is a drawing for explaining the discontinuous bone portion in the porous structure in the state of FIG. 5(a). [Figure 6] FIG. 6(a) is an oblique view showing a cell partition having a discontinuous bone portion in a porous structure according to a second embodiment of the present invention, and FIG. 6(b) is a drawing for explaining the discontinuous bone portion in the porous structure of FIG. 6(a). [Figure 7] Figure 7(a) is a drawing for explaining a first modified example of a discontinuous bone portion in a porous structure relating to the second embodiment of the present invention, and Figure 7(b) is a drawing for explaining a second modified example of a discontinuous bone portion in a porous structure relating to the second embodiment of the present invention. [Figure 8] FIG. 8(a) is an oblique view showing a cell partition having a discontinuous bone portion in a porous structure according to a third embodiment of the present invention, and FIG. 8(b) is a drawing for explaining the discontinuous bone portion in the porous structure of FIG. 8(a). [Figure 9] FIG. 9(a) is an oblique view showing a cell partition having a discontinuous bone portion in a porous structure according to a fourth embodiment of the present invention, and FIG. 9(b) is a drawing for explaining the discontinuous bone portion in the porous structure of FIG. 9(a). [Figure 10] 13 is a view for explaining a first modified example of a discontinuous bone portion in a porous structure according to a fourth embodiment of the present invention. [Figure 11] FIG. 11(a) is an oblique view showing a cell partition having a discontinuous bone portion in a porous structure according to a fifth embodiment of the present invention, and FIG. 11(b) is a drawing for explaining the discontinuous bone portion in the porous structure of FIG. 11(a). [Figure 12] FIG. 12(a) is an oblique view showing a cell partition having a discontinuous bone portion in a porous structure according to a sixth embodiment of the present invention, and FIG. 12(b) is a drawing for explaining the discontinuous bone portion in the porous structure of FIG. 12(a). [Figure 13] FIG. 13 is a perspective view showing a part of a porous structure according to a seventh embodiment of the present invention in its natural state without compressive deformation. [Figure 14] FIG. 14 is a perspective view of a portion of the porous structure of FIG. 13, with the bridges stretched out for convenience. [Figure 15] FIG. 14 is a perspective view showing the porous structure of FIG. 13 in a state where it is compressed and deformed in a predetermined load input direction. [Figure 16] FIG. 13 is a perspective view showing a cell partition portion in a porous structure according to an eighth embodiment of the present invention. [Figure 17] FIG. 1 is a perspective view that shows a schematic view of a vehicle seat that can be provided with a porous structure according to any embodiment of the present invention. [Figure 18] FIG. 1 is a diagram for explaining a method for producing a porous structure according to one embodiment of the present invention, which can be used to produce a porous structure according to any embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The porous structure and the method for manufacturing the porous structure of the present invention are suitable for use in cushioning materials, for example, in any vehicle seat and any vehicle seat pad (seat pad), and are particularly suitable for use in vehicle seats and vehicle seat pads.

[0026] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the porous structure and the method for producing the porous structure according to the present invention will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals.

[0027] [First embodiment of the porous structure] First, a porous structure 1 according to a first embodiment of the present invention will be described with reference to Figs. 1 to 5. Figs. 1 to 4 show a part of the porous structure 1 according to this embodiment in a natural state. Here, the "natural state" refers to a state in which no external force is applied, and further, no compressive deformation or the like is occurring. Fig. 5 shows a part of the porous structure 1 according to this embodiment in a state in which it is compressively deformed in a predetermined load input direction ID.

[0028] The porous structure 1 is shaped by a 3D printer. The manufacturing method of the porous structure 1 will be described later in detail with reference to FIG. 18. By manufacturing the porous structure 1 using a 3D printer, the manufacturing is simpler than the conventional method of foaming by chemical reaction, and the desired configuration can be obtained. In addition, with the future technological advances in 3D printers, it is expected that in the future, it will be possible to realize manufacturing using 3D printers in a shorter time and at a lower cost. In addition, by manufacturing the porous structure 1 using a 3D printer, the configuration of the porous structure 1 corresponding to various required characteristics can be realized simply and as desired.

[0029] The porous structure 1 is made of flexible resin or rubber. Here, the "flexible resin" refers to a resin that can be deformed when a load is applied, and for example, an elastomer-based resin is preferable, and polyurethane is more preferable. Examples of rubber include natural rubber and synthetic rubber. Since the porous structure 1 is made of a flexible resin or rubber, it can be compressed and restored in response to the application and release of a load from the user, and therefore can have cushioning properties. From the viewpoint of ease of manufacturing using a 3D printer, the porous structure 1 is more preferably made of a flexible resin than of rubber. From the viewpoint of ease of manufacturing using a 3D printer, it is preferable that the entire porous structure 1 is made of a material having the same composition. However, the porous structure 1 may be made of materials having different compositions depending on the part. When the porous structure 1 is manufactured using a 3D printer, a resin made of photocurable polyurethane (particularly ultraviolet-curable polyurethane) can be used as the material for forming the porous structure 1. As the photocurable polyurethane (particularly ultraviolet-curable polyurethane), a resin made of urethane acrylate or urethane methacrylate can be used. Examples of such resins include those described in US4337130.

[0030] The porous structure 1 includes a skeleton 2 that forms the skeleton of the porous structure 1. The skeleton 2 defines a large number of cell pores C. The skeleton 2 is present throughout the porous structure 1 and is made of flexible resin or rubber. In this embodiment, the portions of the porous structure 1 other than the skeleton 2 are voids, in other words, the porous structure 1 is made of only the skeleton 2.

[0031] As shown in FIG. 1, the skeleton 2 of the porous structure 1 includes a plurality of bones 2B and a plurality of joints 2J throughout the skeleton. As shown in FIGS. 2 to 4, in this embodiment, some (one or more) of the bones 2B included in the skeleton 2 are continuous bones 2BA that are continuous throughout the skeleton, and the remaining (one or more) of the bones 2B included in the skeleton 2 are discontinuous bones 2BB that are divided into two parts (a first divided bone 51 and a second divided bone 52 described later). Each continuous bone 2BA is formed in a columnar shape. Each bone 2B extends from one end 2Be to the other end 2Be. As shown in FIG. 3, one end 51r of the first divided bone portion 51 constitutes one end 2Be of the bone portion 2B, and is hereinafter referred to as the "root portion 51r" for convenience. The other end 51t of the first divided bone portion 51 is not connected to other parts of the skeleton portion 2, and is hereinafter referred to as the "tip portion 51t" for convenience. One end 52r of the second divided bone portion 52 constitutes the other end 2Be of the bone portion 2B, and is hereinafter referred to as the "root portion 52r" for convenience. The other end 52t of the second divided bone portion 52 is not connected to other parts of the skeleton portion 2, and is hereinafter referred to as the "tip portion 52t" for convenience. In addition, when describing the bone portion 2B in this specification, the discontinuous bone portion 2BB will be viewed as a single part including the first divided bone portion 51 and the second divided bone portion 52, regardless of whether the first divided bone portion 51 and the second divided bone portion 52 are in contact with each other in the natural state. Each joint 2J joins end portions 2Be in the extension direction of a plurality of (eg, three) bone portions 2B extending in mutually different directions at locations where these end portions 2Be are adjacent to each other. The skeleton 2 has a plurality of bones 2B and a plurality of connecting portions 2J over its entirety, and thus has a mesh-like shape. The skeleton 2 is preferably constructed as a single unit (that is, made of one part), but may be constructed of a plurality of separate parts.

[0032] In Figs. 1 to 4, the skeleton line O of the skeleton 2 is shown by a dashed line in a part of the porous structure 1. The skeleton line O of the skeleton 2 includes the skeleton line O of each bone portion 2B and the skeleton line O of each joint portion 2J. The skeleton line O of the bone portion 2B is the central axis of the bone portion 2B. The central axis of the bone portion 2B is a line smoothly connecting the centers of gravity of the shape of the bone portion 2B in a cross section perpendicular to the extension direction of the bone portion 2B at each point in the extension direction of the bone portion 2B. The central axis of the discontinuous bone portion 2BB is a line smoothly connecting the centers of gravity of the shape of the discontinuous bone portion 2BB in a cross section perpendicular to the extension direction of the discontinuous bone portion 2BB at each point in the extension direction of the discontinuous bone portion 2BB when the first divided bone portion 51 and the second divided bone portion 52 are viewed together as one part. The skeleton line O (central axis) of the discontinuous bone part 2BB may be different from the respective central axes of the first divided bone part 51 and the second divided bone part 52. The central axis of the first divided bone part 51 is a line smoothly connecting the centers of gravity of the shape of the first divided bone part 51 in a cross section perpendicular to the extension direction of the first divided bone part 51 at each point in the extension direction of the first divided bone part 51. The central axis of the second divided bone part 52 is a line smoothly connecting the centers of gravity of the shape of the second divided bone part 52 in a cross section perpendicular to the extension direction of the second divided bone part 52 at each point in the extension direction of the second divided bone part 52. The extension direction of the bone part 2B is the extension direction of the skeleton line O of the bone part 2B (the part of the skeleton line O corresponding to the bone part 2B. The same applies below.). The skeleton line O of the joint portion 2J is an extension line portion formed by smoothly extending the central axes of the bone portions 2B joined to the joint portion 2J into the joint portion 2J and connecting them to each other. The porous structure 1 has a skeleton 2 over almost the entire structure, and therefore is capable of compressing and restoring deformation in response to the application and release of a load while ensuring breathability, thereby providing excellent characteristics as a cushioning material.

[0033] In this embodiment, each continuous bone portion 2BA is columnar and extends linearly (FIGS. 1 to 4). Also, in this embodiment, each first divided bone portion 51 and each second divided bone portion 52 is columnar and extends linearly (FIGS. 1 to 4). Accordingly, each discontinuous bone portion 2BB is approximately columnar and extends linearly. However, among the continuous bone parts 2BA constituting the skeletal part 2, some or all of the continuous bone parts 2BA may extend while being curved. In this case, by having some or all of the continuous bone parts 2BA bent, it is possible to prevent a sudden change in shape of the continuous bone parts 2BA and thus the porous structure 1 when a load is input, and to suppress local buckling. From the same viewpoint, among the first divided bone parts 51 constituting the skeletal part 2, some or all of the first divided bone parts 51 may extend while being curved. Furthermore, among the second divided bone parts 52 constituting the skeletal part 2, some or all of the second divided bone parts 52 may extend while being curved. Furthermore, among the discontinuous bone parts 2BB constituting the skeletal part 2, some or all of the discontinuous bone parts 2BB may extend while being substantially curved.

[0034] In this example, each of the continuous bone portions 2BA constituting the skeletal portion 2 has approximately the same shape and length (FIGS. 1 to 4). However, this is not limited to this example, and the shape and / or length of each of the continuous bone portions 2BA constituting the skeletal portion 2 may not be the same, for example, the shape and / or length of some of the continuous bone portions 2BA may be different from the other continuous bone portions 2BA. In this case, by making the shape and / or length of the continuous bone portions 2BA of a specific portion of the skeletal portion 2 different from the other portions, it is possible to intentionally obtain different mechanical properties.

[0035] In this example, the width W0 (FIG. 4) and cross-sectional area of ​​each continuous bone portion 2BA are constant over the entire length of the continuous bone portion 2BA (that is, uniform along the extending direction of the continuous bone portion 2BA) (FIGS. 1 to 4). Here, the cross-sectional area of ​​the continuous bone portion 2BA refers to the cross-sectional area of ​​a cross section perpendicular to the skeletal line O (central axis) of the continuous bone portion 2BA. Also, the width W0 (FIG. 4) of the continuous bone portion 2BA refers to the maximum width of the cross section when measured along the cross section perpendicular to the skeletal line O of the continuous bone portion 2BA. However, in each example described in this specification, the width W0 and / or cross-sectional area of ​​some or all of the continuous bone parts 2BA constituting the skeletal part 2 may be non-uniform along the extension direction of the continuous bone part 2BA. For example, the width W0 of some or all of the continuous bone parts 2BA constituting the skeletal part 2 may be gradually increased or decreased toward both ends in the extension direction of the continuous bone part 2BA in a portion including the end parts 2Be on both sides in the extension direction of the continuous bone part 2BA. Also, the cross-sectional area of ​​some or all of the continuous bone parts 2BA constituting the skeletal part 2 may be gradually increased or decreased toward both ends in the extension direction of the continuous bone part 2BA in a portion including the end parts 2Be on both sides in the extension direction of the continuous bone part 2BA. In this specification, the term "gradual change (increase or decrease)" refers to a constant smooth change (increase or decrease) without becoming constant midway. Similarly, in this example, the width W1 (FIG. 4) and cross-sectional area of ​​each first divided bone portion 51 are constant over the entire length of the first divided bone portion 51 (i.e., uniform along the extension direction of the first divided bone portion 51) (FIGS. 1, 3, 4). Also, in this example, the width W2 (FIG. 4) and cross-sectional area of ​​each second divided bone portion 52 are constant over the entire length of the second divided bone portion 52 (i.e., uniform along the extension direction of the second divided bone portion 52) (FIGS. 1, 3, 4). Here, the cross-sectional area of ​​the first divided bone part 51 refers to the cross-sectional area of ​​a cross section perpendicular to the central axis of the first divided bone part 51. The cross-sectional area of ​​the second divided bone part 52 refers to the cross-sectional area of ​​a cross section perpendicular to the central axis of the second divided bone part 52. Moreover, the width W1 (Fig. 4) of the first divided bone part 51 refers to the maximum width in the cross section when measured along the cross section perpendicular to the central axis of the first divided bone part 51. The width W2 (Fig. 4) of the second divided bone part 52 refers to the maximum width in the cross section when measured along the cross section perpendicular to the central axis of the width W2 of the second divided bone part 52. However, in each example described in this specification, the width W1 and / or cross-sectional area of ​​some or all of the first divided bone parts 51 constituting the skeleton 2 may be non-uniform along the extension direction of the first divided bone parts 51. Also, in each example described in this specification, the width W2 and / or cross-sectional area of ​​some or all of the second divided bone parts 52 constituting the skeleton 2 may be non-uniform along the extension direction of the second divided bone parts 52.

[0036] In each example described in this specification, from the viewpoint of simplifying the structure of the skeleton 2 and thus facilitating the manufacture of the porous structure 1 by a 3D printer, the minimum value of the width W0 (FIG. 4) of the continuous bone portion 2BA is preferably 0.05 mm or more, and more preferably 0.10 mm or more. When the minimum value of the width W0 is 0.05 mm or more, it can be molded with the resolution of a high-performance 3D printer, and when it is 0.10 mm or more, it can be molded with the resolution of not only a high-performance 3D printer but also a general-purpose 3D printer. Here, the "minimum value of the width W0 of the continuous bone portion 2BA" refers to the width W0 in the extension direction portion of the continuous bone portion 2BA where the width W0 is the smallest. Similarly, in each example described in this specification, the minimum value of the width W1 (FIG. 4) of the first divided bone part 51 is preferably 0.05 mm or more, and more preferably 0.10 mm or more. In each example described in this specification, the minimum value of the second divided bone part 52 (FIG. 4) is preferably 0.05 mm or more, and more preferably 0.10 mm or more. Here, the "minimum value of the width W1 of the first divided bone part 51" refers to the width W1 in the extension direction part where the width W1 of the first divided bone part 51 is the smallest. In addition, the "minimum value of the width W2 of the second divided bone part 52" refers to the width W2 in the extension direction part where the width W2 of the second divided bone part 52 is the smallest. On the other hand, in each example described in this specification, from the viewpoints of improving the accuracy of the outer edge (outer contour) shape of the skeleton part 2, reducing the gaps (spacing) between the cell holes C, and improving the characteristics as a cushioning material, it is preferable that the maximum value of the width W0 of the continuous bone part 2BA is 2.0 mm or less. Here, the "maximum value of the width W0 of the continuous bone part 2BA" refers to the width W0 of the continuous bone part 2BA in the extension direction where the width W0 is maximum. Similarly, in each example described in this specification, the maximum value of the width W1 of the first divided bone part 51 is preferably 2.0 mm or less. In addition, in each example described in this specification, the maximum value of the width W2 of the second divided bone part 52 is preferably 2.0 mm or less. Here, the "maximum value of the width W1 of the first divided bone part 51" refers to the width W1 in the extension direction part of the first divided bone part 51 where the width W1 is maximum. In addition, the "maximum value of the width W2 of the second divided bone part 52" refers to the width W2 in the extension direction part of the second divided bone part 52 where the width W2 is maximum. It is preferable that each continuous bone portion 2BA constituting the skeletal portion 2 satisfies this configuration, but only some of the continuous bone portions 2BA constituting the skeletal portion 2 may satisfy this configuration, and even in this case, the same effect can be obtained, although there may be differences in the degree. It is preferable that each first divided bone portion 51 constituting the skeletal portion 2 satisfies this configuration, but only some of the first divided bone portions 51 constituting the skeletal portion 2 may satisfy this configuration, and even in this case, the same effect can be obtained, although there may be differences in the degree. It is preferable that each second divided bone portion 52 constituting the skeletal portion 2 satisfies this configuration, but only some of the second divided bone portions 52 constituting the skeletal portion 2 may satisfy this configuration, and even in this case, the same effect can be obtained, although there may be differences in the degree.

[0037] In this example, each continuous bone portion 2BA constituting the skeletal portion 2 is columnar and has a circular (perfect circle) cross-sectional shape (Figs. 1 to 4). Also, in this example, each first divided bone portion 51 constituting the skeletal portion 2 is columnar and has a circular (perfect circle) cross-sectional shape (Figs. 1, 3, 4). Also, in this example, each second divided bone portion 52 constituting the skeletal portion 2 is columnar and has a circular (perfect circle) cross-sectional shape (Figs. 1, 3, 4). This simplifies the structure of the skeleton 2, making it easier to model using a 3D printer. In addition, it is easy to reproduce the mechanical properties of general polyurethane foam manufactured through a process of foaming by chemical reaction. Therefore, the properties of the porous structure 1 as a cushioning material can be improved. In addition, by configuring the continuous bone portion 2BA, the first divided bone portion 51, and the second divided bone portion 52 in a columnar shape in this way, the durability of the skeleton 2 can be improved compared to the case where the continuous bone portion 2BA, the first divided bone portion 51, and the second divided bone portion 52 are replaced with thin membrane-like portions. The cross-sectional shape of each continuous bone portion 2BA is the shape in a cross section perpendicular to the central axis (skeleton line O) of the continuous bone portion 2BA. The cross-sectional shape of each first divided bone portion 51 is the shape in a cross section perpendicular to the central axis of the first divided bone portion 51. The cross-sectional shape of each second divided bone portion 52 is the shape in a cross section perpendicular to the central axis of the second divided bone portion 52. In addition, without being limited to this example, only some of the continuous bone parts 2BA among the continuous bone parts 2BA constituting the skeletal part 2 may satisfy this configuration, and in that case, the same effect can be obtained, although there may be differences in degree. Also, only some of the first divided bone parts 51 among the first divided bone parts 51 constituting the skeletal part 2 may satisfy this configuration, and in that case, the same effect can be obtained, although there may be differences in degree. Also, only some of the second divided bone parts 52 among the second divided bone parts 52 constituting the skeletal part 2 may satisfy this configuration, and in that case, the same effect can be obtained, although there may be differences in degree. For example, in each example described in this specification, the cross-sectional shape of all or a part of the continuous bone parts 2BA constituting the skeleton 2 may be a polygon (equilateral triangle, a triangle other than an equilateral triangle, a rectangle, etc.) or a circle other than a perfect circle (an ellipse, etc.), and even in this case, the same effect as in this example is obtained. Also, in each example described in this specification, the cross-sectional shape of all or a part of the first divided bone parts 51 constituting the skeleton 2 may be a polygon (equilateral triangle, a triangle other than an equilateral triangle, a rectangle, etc.) or a circle other than a perfect circle (an ellipse, etc.), and even in this case, the same effect as in this example is obtained. Also, in each example described in this specification, the cross-sectional shape of all or a part of the second divided bone parts 52 constituting the skeleton 2 may be a polygon (equilateral triangle, a triangle other than an equilateral triangle, a rectangle, etc.) or a circle other than a perfect circle (an ellipse, etc.), and even in this case, the same effect as in this example is obtained. In each example described herein, each continuous bone portion 2BA may have a uniform cross-sectional shape along its extension direction, or may be non-uniform along its extension direction. In each example described herein, each first divided bone portion 51 may have a uniform cross-sectional shape along its extension direction, or may be non-uniform along its extension direction. In each example described herein, each second divided bone portion 52 may have a uniform cross-sectional shape along its extension direction, or may be non-uniform along its extension direction. In each example described in this specification, the cross-sectional shapes of the continuous bone portions 2BA may be different from each other. Also, in each example described in this specification, the cross-sectional shapes of the first divided bone portions 51 may be different from each other. Also, in each example described in this specification, the cross-sectional shapes of the second divided bone portions 52 may be different from each other.

[0038] In each example described in this specification, it is preferable that the ratio (VB×100 / VS [%)) of the volume VB occupied by the skeleton part 2 to the apparent volume VS of the skeleton part 2 is 3 to 10%. With this configuration, the reaction force generated in the skeleton part 2 when a load is applied to the skeleton part 2, and thus the hardness of the skeleton part 2 (and thus the hardness of the porous structure 1) can be improved as a cushioning material, for example, as a seat pad (particularly a seat pad for a vehicle). Here, "apparent volume VS of skeletal part 2" refers to the volume of the entire internal space surrounded by the outer edge (outer contour) of skeletal part 2 (the sum of the volume occupied by skeletal part 2, the volume occupied by membrane 3 (Figure 16) described below if provided, and the volume occupied by voids). Assuming that the material constituting the skeleton 2 is the same, the higher the ratio of the volume VB occupied by the skeleton 2 to the apparent volume VS of the skeleton 2, the harder the skeleton 2 (and thus the porous structure 1) will be. Conversely, the lower the ratio of the volume VB occupied by the skeleton 2 to the apparent volume VS of the skeleton 2, the softer the skeleton 2 (and thus the porous structure 1) will be. From the viewpoint of improving the reaction force generated in the skeleton 2 when a load is applied to the skeleton 2, and thus the hardness of the skeleton 2 (and thus the porous structure 1) as a cushioning material, for example, as a seat pad (particularly a seat pad for a vehicle), it is more preferable that the proportion of the volume VB occupied by the skeleton 2 in the apparent volume VS of the skeleton 2 be 4 to 8%. Any method may be used to adjust the proportion of the volume VB occupied by the skeletal portion 2 in the apparent volume VS of the skeletal portion 2, but examples include a method of adjusting the thickness (cross-sectional area) of some or all of the bone portions 2B that constitute the skeletal portion 2 and / or the size (cross-sectional area) of some or all of the joint portions J that constitute the skeletal portion 2.

[0039] In each example described in this specification, the 25% hardness of the porous structure 1 is preferably 60 to 500 N, more preferably 100 to 450 N. Here, the 25% hardness (N) of the porous structure 1 is a measured value obtained by measuring the load (N) required to compress the porous structure by 25% in an environment of 23°C and relative humidity of 50% using an Instron type compression tester. This allows the porous structure 1 to have a good hardness as a cushioning material, for example, as a seat pad (particularly a seat pad for a vehicle).

[0040] As shown in Figs. 1 to 4, in this embodiment, the skeleton 2 has a plurality of cell partitions 21 (as many as the number of cell holes C) that partition the cell holes C therein. The skeleton 2 has a structure in which a large number of cell partitions 21 are connected to each other. Each cell partition 21 is composed of a plurality of bones 2B and a plurality of joints 2J. In the example of Fig. 1, the plurality of cell partitions 21 provided in the skeleton 2 include one or more (plural in the example of Fig. 1) cell partitions 21A that do not have a discontinuous bone portion 2BB, and one or more (plural in the example of Fig. 1) cell partitions 21B that have one or more (plural in the example of Fig. 1). However, in this embodiment, each cell partition 21 provided in the skeleton 2 may be a cell partition 21B that has one or more discontinuous bone portions 2BB. It is preferable that each of the cell partitions 21B having one or more discontinuous bone portions 2BB also has one or more continuous bone portions 2BA as in the example of FIG. Fig. 2 shows a cell partition 21A that does not have a discontinuous bone portion 2BB, among the multiple cell partitions 21 provided in the porous structure 1 of Fig. 1. In this cell partition 21A, each bone portion 2B is a continuous bone portion 2BA. Fig. 3 shows a cell partition 21B that has one or more (multiple in the example of Fig. 3) discontinuous bone portions 2BB, among the multiple cell partitions 21 provided in the porous structure 1 of Fig. 1. As shown in Figs. 3 and 4, each cell partition 21 has a plurality of annular portions 211 (14 in this example). Each annular portion 211 is configured in an annular (including substantially annular) shape, and defines a substantially flat imaginary plane V1 by an inner peripheral edge 2111 of each annular (including substantially annular) portion. The imaginary plane V1 is a virtual plane (i.e., a virtual closed plane) defined by the inner peripheral edge 2111 of the annular portion 211. In each cell partition 21, the multiple annular portions 211 constituting the cell partition 21 are connected to each other such that the imaginary planes V1 defined by the respective inner peripheral edge portions 2111 do not intersect with each other. The cell hole C is defined by a plurality of annular portions 211 constituting the cell partitioning portion 21 and a plurality of imaginary surfaces V1 defined by the plurality of annular portions 211. In general terms, the annular portions 211 are portions defining the sides of the three-dimensional shape of the cell hole C, and the imaginary surfaces V1 are portions defining the constituent surfaces of the three-dimensional shape of the cell hole C. Each annular portion 211 is composed of a plurality of bone portions 2B and a plurality of connecting portions 2J that connect the ends 2Be of the plurality of bone portions 2B to each other. The connection portion between a pair of mutually connected annular portions 211 is composed of one bone portion 2B and a pair of joint portions 2J on both sides thereof, which are shared by the pair of annular portions 211. That is, each bone portion 2B and each joint portion 2J is shared by the adjacent multiple annular portions 211. Each imaginary surface V1 defines a portion of one cell hole C by one surface of the imaginary surface V1 (the front surface of the imaginary surface V1), and defines a portion of another cell hole C by the other surface of the imaginary surface V1 (the back surface of the imaginary surface V1). In other words, each imaginary surface V1 defines a portion of a different cell hole C by both its front and back surfaces. In further other words, each imaginary surface V1 is shared by a pair of cell holes C adjacent to the imaginary surface V1 (i.e., a pair of cell holes C sandwiching the imaginary surface V1 therebetween). Moreover, each annular portion 211 is shared by a pair of cell partitions 21 adjacent to the annular portion 211 (i.e., a pair of cell partitions 21 sandwiching the annular portion 211) (FIGS. 1 and 4). In other words, each annular portion 211 constitutes a part of each of the pair of cell partitions 21 adjacent to each other. In the example of Figs. 1 to 4, each imaginary surface V1 in the porous structure 1 is not covered by the membrane 3 (Fig. 16) and is open, i.e., forms an opening. Therefore, the cell holes C communicate with each other through the imaginary surface V1, and ventilation between the cell holes C is possible. This improves the ventilation of the skeletal portion 2 and facilitates the compression and restoration deformation of the skeletal portion 2 in response to the application and release of a load.

[0041] As shown in Figs. 1 to 4, in this example, the skeleton line O of each cell partition 21 is substantially polyhedral in shape, and therefore each cell hole C is substantially polyhedral in shape. More specifically, in the example of Figs. 1 to 4, the skeleton line O of each cell partition 21 is substantially Kelvin tetradecahedron (truncated octahedron) in shape, and therefore each cell hole C is substantially Kelvin tetradecahedron (truncated octahedron) in shape. The Kelvin tetradecahedron (truncated octahedron) is a polyhedron composed of six regular quadrilateral constituent faces and eight regular hexagonal constituent faces. The cell holes C constituting the skeleton 2 are arranged with regularity so as to fill the internal space surrounded by the outer edge (outer contour) of the skeleton 2 (i.e., so that the cell holes C are arranged without any unnecessary gaps, in other words, so as to reduce the gaps (spacing) between the cell holes C).

[0042] As shown in Figs. 1 to 4, in this example, the multiple (14 in this example) annular portions 211 constituting the cell partition portion 21 each include one or more (six in this example) small annular portions 211S and one or more (eight in this example) large annular portions 211L. Each small annular portion 211S defines a substantially flat small imaginary surface V1S by its annular (including substantially annular) inner peripheral edge portion 2111. Each large annular portion 211L defines a substantially flat large imaginary surface V1L having an area larger than that of the small imaginary surface V1S by its annular (including substantially annular) inner peripheral edge portion 2111. Each of the small imaginary surface V1S and the large imaginary surface V1L is an imaginary plane (i.e., an imaginary closed plane). 2 and 3, in this example, the large annular portion 211L has a skeleton line O that is a substantially regular hexagon, and accordingly, the large imaginary surface V1L also has a substantially regular hexagon. In this example, the small annular portion 211S has a skeleton line O that is a substantially regular quadrangle, and therefore, the small imaginary surface V1S also has a substantially regular quadrangle. Thus, in this example, the small imaginary surface V1S and the large imaginary surface V1L differ not only in area but also in shape (specifically, the number and shape of the constituent surfaces). Each of the large ring portions 211L is composed of a plurality of (six in this example) bone portions 2B and a plurality of (six in this example) joint portions 2J that join the ends 2Be of the bone portions 2B. Each of the small ring portions 211S is composed of a plurality of (four in this example) bone portions 2B and a plurality of (four in this example) joint portions 2J that join the ends 2Be of the bone portions 2B. In the example of Figs. 1 to 4, each of the skeleton lines O of the multiple cell partitions 21 constituting the skeleton 2 is approximately a Kelvin tetradecahedron (truncated octahedron). As described above, a Kelvin tetradecahedron (truncated octahedron) is a polyhedron composed of six regular quadrilateral constituent faces and eight regular hexagonal constituent faces. Accordingly, the cell holes C defined by each cell partition 21 also form approximately a Kelvin tetradecahedron. The skeleton lines O of the multiple cell partitions 21 constituting the skeleton 2 are connected to each other so as to fill the space, forming a mesh shape. In other words, there are no gaps between the skeleton lines O of the multiple cell partitions 21.

[0043] In this way, in this example, the skeleton lines O of the multiple cell partitions 21 constituting the skeleton 2 each form an approximate polyhedron (approximately a Kelvin tetrahedron in this example), and accordingly, since the cell holes C form an approximate polyhedron (approximately a Kelvin tetrahedron in this example), it is possible to make the gaps (spacings) between the cell holes C constituting the porous structure 1 smaller, and more cell holes C can be formed inside the porous structure 1. This also makes the behavior of the compression and restoration deformation of the porous structure 1 in response to the application and release of a load better as a cushioning material, for example, as a seat pad (particularly a seat pad for a vehicle). The gaps (spacings) between the cell holes C correspond to the fleshy parts (bone parts 2B and joint parts 2J) of the skeleton 2 that partition the cell holes C. In addition, in this example, the skeleton lines O of the multiple cell partitions 21 constituting the skeleton 2 are connected to each other so as to fill the space, so that it is possible to further reduce the gaps (intervals) between the cell holes C constituting the porous structure 1. This improves the characteristics of the porous structure as a cushioning material.

[0044] The approximate polyhedron formed by the skeleton lines O of the cell partitioning portion 21 (and thus the approximate polyhedron formed by the cell holes C) is not limited to the examples shown in the figures, and any arbitrary shape is possible. For example, it is preferable that the approximate polyhedron formed by the skeleton lines O of the multiple cell partitions 21 constituting the skeleton part 2 (and thus the approximate polyhedron formed by the cell holes C) is one that can be space-filling (can be arranged without gaps). This allows the skeleton lines O of the multiple cell partitions 21 constituting the skeleton part 2 to be connected to each other so as to fill the space, thereby improving the characteristics of the porous structure as a cushioning material. In this case, the approximate polyhedron formed by the skeleton lines O of the multiple cell partitions 21 constituting the skeleton part 2 (and thus the approximate polyhedron formed by the cell holes C) may include only one type of approximate polyhedron as in this example, or may include multiple types of approximate polyhedrons. Here, with respect to the polyhedron, the "type" refers to the shape (the number of constituent faces and the shape), and specifically, it means that two polyhedrons that have different shapes (the number of constituent faces and the shape) are treated as two types of polyhedrons, but two polyhedrons that have the same shape and only different dimensions are treated as the same type of polyhedron. Examples of the approximate polyhedron formed by the skeleton lines O of the multiple cell partitions 21 constituting the skeleton 2, which can fill space and include only one type of approximate polyhedron, include an approximate regular triangular prism, an approximate regular hexagonal prism, an approximate cube, an approximate rectangular parallelepiped, and an approximate rhombic dodecahedron, in addition to an approximate Kelvin tetrahedron. As shown in the examples of the figures, when the shape of the skeleton lines O of the cell partitions 21 is an approximate Kelvin tetrahedron (truncated octahedron), it is easiest to reproduce the characteristics of a cushioning material equivalent to that of a general polyurethane foam manufactured through a process of foaming by chemical reaction, compared to other shapes. Furthermore, when the shape of the skeleton lines O of the cell partitions 21 is an approximate Kelvin tetrahedron (truncated octahedron), it is possible to obtain equal mechanical properties in all directions. When the approximate polyhedron formed by the skeleton lines O of the multiple cell partitions 21 constituting the skeleton 2 can fill space and includes multiple types of approximate polyhedrons, examples of the approximate polyhedron include a combination of an approximately regular tetrahedron and an approximately regular octahedron, a combination of an approximately regular tetrahedron and an approximately truncated tetrahedron, a combination of an approximately regular octahedron and an approximately truncated hexahedron, etc. Note that these are examples of combinations of two types of approximate polyhedrons, but a combination of three or more types of approximate polyhedrons is also possible. Furthermore, the approximate polyhedron formed by the skeletal lines O of the multiple cell partition sections 21 that make up the skeletal section 2 (and ultimately the approximate polyhedron formed by the cell holes C) can be, for example, any approximately regular polyhedron (an approximately convex polyhedron in which all faces are approximately regular polygons that are congruent and the number of faces that meet at all vertices is equal), an approximately semi-regular polyhedron (an approximately convex polyhedron in which all faces are approximately regular polygons and all vertices have congruent shapes (the types and order of approximately regular polygons that meet at the vertices are the same) other than an approximately regular polyhedron), an approximately prism, an approximately pyramid, etc. Furthermore, the skeleton lines O of some or all of the cell partitions 21 constituting the skeleton 2 may have an approximately three-dimensional shape other than an approximately polyhedron (for example, an approximately sphere, an approximately ellipsoid, an approximately cylinder, etc.). Furthermore, some or all of the cell holes C constituting the skeleton 2 may have an approximately three-dimensional shape other than an approximately polyhedron (for example, an approximately sphere, an approximately ellipsoid, an approximately cylinder, etc.).

[0045] The multiple annular portions 211 constituting the cell partitioning portion 21 include small annular portions 211S and large annular portions 211L of different sizes, which makes it possible to further reduce the gaps (spacing) between the cell holes C constituting the skeletal portion 2. Furthermore, when the small annular portions 211S and large annular portions 211L have different shapes (number of sides) as in this example, it becomes possible to further reduce the gaps (spacing) between the cell holes C constituting the skeletal portion 2. However, the multiple annular portions 211 constituting the cell partition 21 may each have the same size and / or shape (number of sides). When the annular portions 211 constituting the cell partition 21 have the same size and shape (number of sides), equal mechanical properties can be obtained in all directions.

[0046] As in this example, the skeleton lines O of some or all (in this example, all) of the annular portions 211 constituting the cell partitioning portion 21 (and thus some or all (in this example, all) of the imaginary surfaces V1 constituting the cell partitioning portion 21) are substantially polygonal, so that the intervals between the cell holes C constituting the skeleton portion 2 can be made smaller. In addition, the behavior of the compression and restoration deformation of the skeleton portion 2 in response to the application and release of a load becomes better as a seat pad, particularly as a seat pad for a vehicle. In addition, since the shape of the annular portion 211 (and thus the shape of the imaginary surface V1) is simplified, the manufacturability and ease of adjustment of the characteristics can be improved. Note that, when at least one annular portion 211 (and thus at least one imaginary surface V1 of the imaginary surfaces V1 constituting the skeleton portion 2) of the annular portions 211 constituting the skeleton portion 2 satisfies this configuration, the same effect can be obtained, although to a different degree. In addition, the skeleton line O of at least one of the annular portions 211 constituting the skeleton portion 2 (and thus at least one of the imaginary surfaces V1 constituting the skeleton portion 2) may be any substantially polygonal shape other than a substantially regular hexagon or a substantially regular quadrangle as in this example, or a substantially planar shape other than a substantially polygonal shape (for example, a substantially circle (substantially a perfect circle, a substantially ellipse, etc.)). When the shape of the skeleton line O of the annular portion 211 (and thus the shape of the imaginary surface V1) is a substantially circle (substantially a perfect circle, a substantially ellipse, etc.), the shape of the annular portion 211 (and thus the shape of the imaginary surface V1) becomes simple, which improves manufacturability and ease of adjustment of characteristics, and provides more uniform mechanical characteristics. For example, when the shape of the skeleton line O of the annular portion 211 (and thus the shape of the virtual surface V1) is an ellipse (horizontal ellipse) that is elongated in a direction approximately perpendicular to the specified load input direction ID, the annular portion 211, and thus the skeleton portion 2 (and thus the porous structure 1), becomes more easily deformed (softer) in response to the input of load than when the skeleton line O is an ellipse (vertical ellipse) that is elongated in a direction approximately parallel to the specified load input direction ID.

[0047] In this example, it is preferable that the skeleton 2 has at least one cell hole C having a diameter of 5 mm or more. This makes it easier to manufacture the porous structure 1 using a 3D printer. If the diameter of each cell hole C of the skeleton 2 is less than 5 mm, the structure of the skeleton 2 becomes too complicated, and it may be difficult to generate three-dimensional shape data (CAD data, etc.) representing the three-dimensional shape of the porous structure 1, or 3D printing data generated based on the three-dimensional shape data, on a computer. In addition, since the porous structure constituting the conventional cushioning material was manufactured through a foaming process using a chemical reaction, it was not easy to form cell holes C with a diameter of 5 mm or more. Furthermore, by having the skeletal portion 2 have cell pores C with a diameter of 5 mm or more, the breathability and ease of deformation of the skeletal portion 2 can be improved. From this viewpoint, it is preferable that the diameter of each of the cell pores C constituting the skeleton 2 is 5 mm or more. The larger the diameter of the cell hole C, the easier it is to manufacture the porous structure 1 using a 3D printer, and the easier it is to improve the breathability and ease of deformation. From this viewpoint, it is preferable that the diameter of at least one (preferably all) of the cell holes C in the skeleton 2 is 8 mm or more, more preferably 10 mm or more. On the other hand, if the cell holes C of the skeleton 2 are too large, it becomes difficult to form the outer edge (outer contour) shape of the skeleton 2 (and thus the porous structure 1) neatly (smoothly), and the shape precision of the cushioning material (e.g., a seat pad, particularly a seat pad for a vehicle) may decrease, resulting in a poor appearance. In addition, the characteristics as a cushioning material (e.g., a seat pad, particularly a seat pad for a vehicle) may also become insufficiently good. Therefore, from the viewpoint of improving the appearance and the characteristics as a cushioning material (e.g., a seat pad, particularly a seat pad for a vehicle), the diameter of each cell hole C of the skeleton 2 is preferably less than 30 mm, more preferably 25 mm or less, and even more preferably 20 mm or less. The more cell holes C that the porous structure 1 has and that satisfy the above-mentioned numerical ranges for diameter, the more likely it is that the above-mentioned effects can be obtained. From this viewpoint, it is preferable that the diameter of each of the cell holes C that constitute the porous structure 1 satisfies at least one of the above-mentioned numerical ranges. Similarly, it is more preferable that the average value of the diameters of the cell holes C that constitute the porous structure 1 satisfies at least one of the above-mentioned numerical ranges. In addition, the diameter of the cell hole C refers to the diameter of the circumscribing sphere of the cell hole C when the cell hole C has a shape other than a strictly spherical shape as in this example.

[0048] If the cell holes C of the skeleton 2 are too small, the structure of the skeleton 2 becomes too complicated, and as a result, it may be difficult to generate three-dimensional shape data (CAD data, etc.) representing the three-dimensional shape of the porous structure 1, or 3D modeling data generated based on the three-dimensional shape data, on a computer, making it difficult to manufacture the porous structure 1 using a 3D printer. From the viewpoint of facilitating the manufacture of the porous structure 1 using a 3D printer, it is preferable that the diameter of the cell hole C having the smallest diameter among the cell holes C constituting the skeleton 2 is 0.05 mm or more, and more preferably 0.10 mm or more. When the diameter of the cell hole C having the smallest diameter is 0.05 mm or more, it can be modeled with the resolution of a high-performance 3D printer, and when it is 0.10 mm or more, it can be modeled with the resolution of not only a high-performance 3D printer but also a general-purpose 3D printer.

[0049] As shown in Figures 4 and 5, the porous structure 1 is configured such that a plurality of portions in the skeletal portion 2 interfere with each other when the porous structure 1 is compressively deformed in the predetermined load input direction ID. This causes friction to occur between the plurality of portions in the skeletal portion 2 when the porous structure 1 is compressively deformed in the predetermined load input direction ID. Figure 4 shows the porous structure 1 in its natural state, in which it is not compressively deformed, and Figure 5 shows the porous structure 1 when it is compressively deformed in the predetermined load input direction ID. In this specification, the "predetermined load input direction ID" is preset as a direction in which a main load from a user or the like is input to the porous structure 1. For example, when the porous structure 1 is configured as a cushioning material (for example, a seat pad as in the example of FIG. 17), the predetermined load input direction ID is preferably the thickness direction TD of the cushioning material. In this specification, the term "when undergoing compressive deformation" specifically refers to a period during which the porous structure 1 is undergoing compressive deformation in a state in which none of the cells C of the porous structure 1 are completely crushed. In this specification, "interference" between multiple parts specifically refers to, for example, multiple parts that were previously in contact or non-contact with each other rubbing against each other (moving while still in contact), or multiple parts that were previously in a non-contact state hitting each other (immediately after hitting, they may remain in contact and not move, or they may move while still in contact), etc. More specifically, the porous structure 1 of this embodiment is configured such that the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) of the discontinuous bone portions 2BB rub ​​against each other when the porous structure 1 is compressively deformed in the predetermined load input direction ID (FIGS. 4(b) and 5(b)). As a result, the porous structure 1 is configured such that friction occurs between the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) of the discontinuous bone portions 2BB when the porous structure 1 is compressively deformed in the predetermined load input direction ID. When the porous structure 1 is in its natural state, the first divided bone portion 51 and the second divided bone portion 52 in each of the discontinuous bone portions 2BB may be in contact with each other or in a non-contact state. From the viewpoint of preventing the first divided bone portion 51 and the second divided bone portion 52 in each discontinuous bone portion 2BB from adhering to each other when modeling using a 3D printer, it is preferable that the first divided bone portion 51 and the second divided bone portion 52 in each discontinuous bone portion 2BB are in a non-contact state with each other when the porous structure 1 is in its natural state. More specifically, in this embodiment, as shown in Fig. 3, in at least one (preferably all) discontinuous bone portion 2BB, the first divided bone portion 51 has a first side surface 51S, and the second divided bone portion 52 has a second side surface 52S. The porous structure 1 is configured such that, when compressively deformed in a predetermined load input direction ID, the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other (Figs. 4(b) and 5(b)). As a result, when compressively deformed in the predetermined load input direction ID, the porous structure 1 is configured such that friction occurs between the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB. The "first side surface 51S" of the first divided bone part 51 is a portion of the side surface of the first divided bone part 51 (a portion of the surface of the first divided bone part 51 excluding both end faces in the extension direction) that is configured to rub against the second divided bone part 52 when the porous structure 1 is compressively deformed in the predetermined load input direction ID. The "second side surface 52S" of the second divided bone part 52 is a portion of the side surface of the second divided bone part 52 (a portion of the surface of the second divided bone part 52 excluding both end faces in the extension direction) that is configured to rub against the first divided bone part 51 when the porous structure 1 is compressively deformed in the predetermined load input direction ID. As shown in the example of Fig. 3, it is preferable that the extending directions of the discontinuous bone parts 2BB are substantially parallel to each other. In the example of Fig. 3, the six bone parts 2B substantially parallel to each other in the cell partitioning part 21B are each discontinuous bone parts 2BB, and when the porous structure 1 is compressed and deformed in the predetermined load input direction ID, the first side surface 51S of the first divided bone part 51 and the second side surface 52S of the second divided bone part 52 in each discontinuous bone part 2BB rub ​​against each other. However, among the six bone parts 2B substantially parallel to each other in the cell partitioning part 21B, some (one or more) bone parts 2B may each be discontinuous bone parts 2BB, and when the porous structure 1 is compressed and deformed in the predetermined load input direction ID, the first side surface 51S of the first divided bone part 51 and the second side surface 52S of the second divided bone part 52 in at least one (preferably all) discontinuous bone part 2BB may be configured to rub against each other. As in the example of FIG. 3, it is preferable that the predetermined load input direction ID is substantially parallel to the extending direction of each discontinuous bone portion 2BB.

[0050] According to this embodiment, as described above, the porous structure 1 is configured such that a plurality of parts in the skeleton 2 interfere with each other when the porous structure 1 is compressively deformed in the predetermined load input direction ID. As a result, friction occurs between the plurality of parts in the skeleton 2 when the porous structure 1 is compressively deformed in the predetermined load input direction ID. More specifically, the porous structure 1 of this embodiment is configured such that the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other when the porous structure 1 is compressively deformed in the predetermined load input direction ID. As a result, friction occurs between the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB when the porous structure 1 is compressively deformed in the predetermined load input direction ID. More specifically, in this embodiment, the porous structure 1 is configured such that the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other when the porous structure 1 is compressively deformed in the predetermined load input direction ID. As a result, the porous structure 1 is configured such that friction occurs between the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB when the porous structure 1 is compressively deformed in the predetermined load input direction ID. The generation of this friction can increase the viscosity of the porous structure 1, and thus the dynamic characteristics (specifically, vibration damping characteristics (particularly hysteresis damping characteristics)) of the porous structure of this embodiment can be made different from the dynamic characteristics of the conventional porous structure described above. In addition, by adjusting the number and area of ​​the parts of the skeleton 2 that interfere with each other, the amount of friction can be adjusted, and thus the viscosity and dynamic characteristics of the porous structure 1 can be adjusted. Thus, it is possible to realize a wider variety of dynamic characteristics according to requirements than ever before. In this way, according to the porous structure 1 of this embodiment, the degree of freedom in adjusting the dynamic characteristics of the porous structure 1 can be improved. This is particularly suitable when the porous structure 1 is used in a vehicle seat pad that is subjected to vibration during use.

[0051] The porous structure 1 is not limited to the configuration of the first embodiment shown in Figures 1 to 5, and various configurations can be adopted so that a plurality of portions in the skeleton 2 interfere with each other when compressively deformed in a predetermined load input direction ID. Hereinafter, other embodiments of the porous structure 1 will be illustrated and described, focusing on the differences from the first embodiment shown in Figures 1 to 5. Descriptions of the same points as the embodiment in Figures 1 to 5 will basically be omitted. In the following description of the configuration of the porous structure 1, unless otherwise specified, reference will be made to the configuration of the porous structure 1 when it is in its natural state. The porous structure 1 of each of the embodiments described below is configured so that multiple portions of the skeletal portion 2 interfere with each other when compressed and deformed in a predetermined load input direction ID, thereby achieving the same effects as those of the first embodiment described above.

[0052] [Second embodiment of the porous structure] Figures 6 and 7 are diagrams for explaining a porous structure 1 according to a second embodiment of the present invention. Figure 6 is a diagram for explaining an example of the porous structure 1 according to the second embodiment of the present invention, and Figures 7(a) and 7(b) are diagrams for explaining first and second modified examples of the porous structure 1 according to the second embodiment of the present invention, respectively. In the second embodiment, similarly to the first embodiment, the porous structure 1 is configured such that the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other when the porous structure 1 is compressively deformed in the predetermined load input direction ID. This allows friction to occur between the first divided bone portion 51 and the second divided bone portion 52 in the at least one (preferably all) discontinuous bone portion 2BB when the porous structure 1 is compressively deformed in the predetermined load input direction ID. More specifically, in the second embodiment, as in the first embodiment, in at least one (preferably all) discontinuous bone portion 2BB, the first divided bone portion 51 has a first side surface 51S, and the second divided bone portion 52 has a second side surface 52S, and the porous structure 1 is configured such that the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other when the porous structure 1 is compressed and deformed in a predetermined load input direction ID. As a result, the porous structure 1 is configured such that friction occurs between the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB when the porous structure 1 is compressed and deformed in a predetermined load input direction ID. In the first embodiment (FIGS. 1 to 5), as described above, the first divided bone portion 51 and the second divided bone portion 52 in at least one (in the examples of the figures, all) discontinuous bone portion 2BB are each configured in a columnar shape. In contrast, in the second embodiment (FIGS. 6 to 7), at least one of the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB is configured in a strip shape. More specifically, in each example of FIG. 6 to FIG. 7, the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB are each configured in a strip shape. As shown in an enlarged view in FIG. 6(b), in the at least one discontinuous bone portion 2BB, the side surface of the first divided bone portion 51 has a pair of wide side surfaces 511 located opposite to each other, and a pair of narrow side surfaces 512 located opposite to each other and narrower than the pair of wide side surfaces 511. The first side surface 51S of the first divided bone portion 51 is one of the pair of wide side surfaces 511 of the first divided bone portion 51. Similarly, in the at least one discontinuous bone portion 2BB, the side surface of the second divided bone portion 52 has a pair of wide side surfaces 521 located opposite to each other, and a pair of narrow side surfaces 522 located opposite to each other and narrower than the pair of wide side surfaces 521. The second side surface 52S of the second divided bone portion 52 is one of the pair of wide side surfaces 521 of the second divided bone portion 52. However, although not shown in the drawings, in the second embodiment, only one of the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) of the discontinuous bone portions 2BB may be configured in a strip shape. In that case, the other of the first divided bone portion 51 and the second divided bone portion 52 in the discontinuous bone portion 2BB is configured in, for example, a columnar shape. According to the second embodiment, at least one of the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB is configured in a band shape, and therefore is configured to be wide, so that the first side surface 51S and the second side surface 52S can be more reliably rubbed against each other even when a positional deviation or the like occurs, compared to the first embodiment. Furthermore, according to each example of Figures 6 to 7, the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) of the discontinuous bone portions 2BB are each configured in a strip shape, so that the contact area between the first side surface 51S and the second side surface 52S can be increased compared to the first embodiment, and ultimately the amount of friction generated between the first side surface 51S and the second side surface 52S can be increased.

[0053] In the second embodiment, it is preferable that the first side surface 51S and the second side surface 52S of at least one (preferably all) of the discontinuous bone portions 2BB are not curved and are substantially flat. In this case, the first side surface 51S and the second side surface 52S may be a smooth surface without irregularities, or may have irregularities by having a plurality of protrusions P as in the embodiment of FIG. 8 described later. However, the first side surface 51S and the second side surface 52S of at least one (preferably all) of the discontinuous bone portions 2BB may be curved in the same direction. In this case, the first side surface 51S and the second side surface 52S may be a smooth surface without irregularities, or may have irregularities by having a plurality of protrusions P as in the embodiment of FIG. 8 described later.

[0054] In the example of Figure 6, in at least one (preferably all) of the discontinuous bone portions 2BB, the width of the first side surface 51S of the first divided bone portion 51 gradually increases from the root portion 51r of the first divided bone portion 51 toward the tip portion 51t of the first divided bone portion 51, and the width of the second side surface 52S of the second divided bone portion 52 gradually increases from the root portion 52r of the second divided bone portion 52 toward the tip portion 52t of the second divided bone portion 52. However, the shapes of the first side surface 51S and the second side surface 52S are each arbitrary. For example, as in the first modified example shown in Figure 7(a), at least one (preferably all) of the discontinuous bone portions 2BB may be configured so that the width of the first side surface 51S of the first divided bone portion 51 is constant from the root portion 51r of the first divided bone portion 51 to the tip portion 51t of the first divided bone portion 51, and the width of the second side surface 52S of the second divided bone portion 52 is constant from the root portion 52r of the second divided bone portion 52 to the tip portion 52t of the second divided bone portion 52. Alternatively, as in a second modified example shown in Figure 7(b), at least one (preferably all) of the discontinuous bone portions 2BB may be configured so that the width of the first side surface 51S of the first divided bone portion 51 gradually increases from the root portion 51r of the first divided bone portion 51 toward the tip portion 51t of the first divided bone portion 51, and the width of the second side surface 52S of the second divided bone portion 52 gradually decreases from the root portion 52r of the second divided bone portion 52 toward the tip portion 52t of the second divided bone portion 52.

[0055] [Third embodiment of the porous structure] FIG. 8 is a diagram for explaining a porous structure 1 according to a third embodiment of the present invention. In the third embodiment, as in the first embodiment, the porous structure 1 is configured such that the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other when the porous structure 1 is compressively deformed in the predetermined load input direction ID. This allows friction to occur between the first divided bone portion 51 and the second divided bone portion 52 in the at least one (preferably all) discontinuous bone portion 2BB when the porous structure 1 is compressively deformed in the predetermined load input direction ID. More specifically, in the third embodiment, as in the first embodiment, in at least one (preferably all) discontinuous bone portion 2BB, the first divided bone portion 51 has a first side surface 51S, and the second divided bone portion 52 has a second side surface 52S, and the porous structure 1 is configured such that the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other when the porous structure 1 is compressed and deformed in a predetermined load input direction ID. As a result, the porous structure 1 is configured such that friction occurs between the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB when the porous structure 1 is compressed and deformed in a predetermined load input direction ID. In the first embodiment (FIGS. 1 to 5), the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (in the example of the figures, all) of the discontinuous bone portions 2BB are smooth surfaces (smooth surfaces) without irregularities. In contrast, in the third embodiment (FIG. 8), at least one of the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) of the discontinuous bone portions 2BB has a plurality of protrusions P. As a result, the surface roughness of at least one of the first side surface 51S and the second side surface 52S is higher than the surface roughness of the first divided bone portion 51 other than the first side surface 51S and the surface roughness of the second divided bone portion 52 other than the second side surface 52S. According to the third embodiment, at least one of the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB has a plurality of protrusions P, thereby making the surface roughness of at least one of the first side surface 51S and the second side surface 52S higher than the surface of the first divided bone portion 51 other than the first side surface 51S and the surface of the second divided bone portion 52 other than the second side surface 52S.Therefore, the amount of friction generated between the first side surface 51S and the second side surface 52S can be increased compared to the first embodiment.

[0056] The height of each protrusion P is preferably, for example, 2 mm or less, and more preferably 1 mm or less, from the viewpoint of facilitating rubbing between the first side surface 51S and the second side surface 52S. Also, the height of each protrusion P is preferably, for example, 0.1 mm or more, and more preferably 0.3 mm or more, from the viewpoint of increasing the magnitude of friction generated between the first side surface 51S and the second side surface 52S. Note that the "height of the protrusion P" refers to the height from the base of the protrusion P to the tip of the protrusion P.

[0057] [Fourth embodiment of the porous structure] Figures 9 and 10 are drawings for explaining the porous structure 1 according to the fourth embodiment of the present invention. Figure 9 is a drawing for explaining an example of the porous structure 1 according to the fourth embodiment of the present invention, and Figure 10 is a drawing for explaining a first modified example of the porous structure 1 according to the fourth embodiment of the present invention. In the fourth embodiment, similarly to the first embodiment, the porous structure 1 is configured such that the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other when the porous structure 1 is compressively deformed in the predetermined load input direction ID. This allows friction to occur between the first divided bone portion 51 and the second divided bone portion 52 in the at least one (preferably all) discontinuous bone portion 2BB when the porous structure 1 is compressively deformed in the predetermined load input direction ID. More specifically, in the fourth embodiment, as in the first embodiment, in at least one (preferably all) discontinuous bone portion 2BB, the first divided bone portion 51 has a first side surface 51S, and the second divided bone portion 52 has a second side surface 52S, and the porous structure 1 is configured such that the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other when the porous structure 1 is compressed and deformed in a predetermined load input direction ID. As a result, the porous structure 1 is configured such that friction occurs between the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB when the porous structure 1 is compressed and deformed in a predetermined load input direction ID. In the first embodiment (FIGS. 1 to 5), as described above, the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB are each configured in a columnar shape. In contrast, in the fourth embodiment (FIGS. 9 to 10), in at least one (preferably all) discontinuous bone portion 2BB, the second side surface 52S of the second divided bone portion 52 is configured to surround the first side surface 51S of the first divided bone portion 51 along the circumferential direction of the first divided bone portion 51 when at least the porous structure 1 is compressively deformed in the predetermined load input direction ID. As a result, when the porous structure 1 is compressively deformed in the predetermined load input direction ID, the first side surface 51S slides on the second side surface 52S while being guided by the second side surface 52S. Here, the "circumferential direction of the first divided bone part 51" refers to the rotation direction around the central axis of the first divided bone part 51 (indicated by the dashed line in Figs. 9(b) and 10). 9 and 10, the first divided bone part 51 is configured in a columnar shape, and therefore the first side surface 51S forms a convex surface. On the other hand, in the example of Fig. 9 and 10, the second side surface 52S of the second divided bone part 52 is recessed so as to surround the first divided bone part 51 along the circumferential direction of the first divided bone part 51, and forms a concave surface extending along the extension direction of the second divided bone part 52. Furthermore, the second side 52S of the second divided bone portion 52 (and thus the second divided bone portion 52) may be configured non-annularly so as to surround the first side 51S of the first divided bone portion 51 over only a portion of the circumference of the first divided bone portion 51, as in the examples of Figures 9 and 10, or may be configured annularly so as to surround the first side 51S of the first divided bone portion 51 over the entire circumference of the first divided bone portion 51. In addition, when the porous structure 1 is in its natural state, the second side surface 52S of the second divided bone portion 52 may surround the first side surface 51S of the first divided bone portion 51, as in the example of Figure 9, or may not surround the first side surface 51S of the first divided bone portion 51. According to the fourth embodiment, in at least one (preferably all) of the discontinuous bone parts 2BB, the second side surface 52S of the second divided bone part 52 is configured to surround the first side surface 51S of the first divided bone part 51 along the circumferential direction of the first divided bone part 51 at least when the porous structure 1 is compressed and deformed in the predetermined load input direction ID, so that the contact area between the first side surface 51S and the second side surface 52S can be increased compared to the first embodiment, and thus the amount of friction generated between the first side surface 51S and the second side surface 52S can be increased. In addition, when the porous structure 1 is compressed and deformed in the predetermined load input direction ID, the first side surface 51S slides on the second side surface 52S while being guided by the second side surface 52S, so that the first divided bone part 51 and the second divided bone part 52 can rub against each other more stably.

[0058] In the example of Figure 9, in at least one (preferably all) of the discontinuous bone portions 2BB, the first divided bone portion 51 is cylindrical, so that the first side surface 51S forms a convex rib surface that follows the cylindrical shape, and the second side surface 52S of the second divided bone portion 52 forms a concave rib surface that follows the cylindrical shape. However, the shapes of the first side surface 51S and the second side surface 52S are each arbitrary. For example, as in the first modified example shown in Figure 10, at least one (preferably all) of the discontinuous bone portions 2BB may have a first divided bone portion 51 in the shape of a rectangular prism, whereby a first side surface 51S forms a convex surface that follows the rectangular tubular shape, and a second side surface 52S of the second divided bone portion 52 forms a concave surface that follows the rectangular tubular shape.

[0059] [Fifth embodiment of the porous structure] FIG. 11 is a diagram illustrating a porous structure 1 according to a fifth embodiment of the present invention. In the fifth embodiment, similarly to the first embodiment, the porous structure 1 is configured such that the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other when the porous structure 1 is compressively deformed in the predetermined load input direction ID. This allows friction to occur between the first divided bone portion 51 and the second divided bone portion 52 in the at least one (preferably all) discontinuous bone portion 2BB when the porous structure 1 is compressively deformed in the predetermined load input direction ID. In the fifth embodiment, similarly to the first embodiment, it is preferable that the first divided bone portion 51 and the second divided bone portion 52 each have a columnar shape. In the first embodiment (Figures 1 to 5), as described above, the porous structure 1 is configured so that, when compressed and deformed in a predetermined load input direction ID, the first side surface 51S of the first divided bone portion 51 and the second side surface 52S of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other. In contrast, in the fifth embodiment (Figure 11), in at least one (in the example of the figure, all) discontinuous bone portions 2BB, the first divided bone portion 51 has a first end face 51E at an end (tip portion) 51t in the extension direction of the first divided bone portion 51, which is inclined with respect to the direction perpendicular to the extension direction of the first divided bone portion 51, and the second divided bone portion 52 has a second end face 52E at an end (tip portion) 52t in the extension direction of the second divided bone portion 52, which is inclined with respect to the direction perpendicular to the extension direction of the second divided bone portion 52, the first end face 51E and the second end face 52E are approximately parallel to each other, and the porous structure 1 is configured so that when compressed and deformed in a predetermined load input direction ID, the first end face 51E of the first divided bone portion 51 and the second end face 52E of the second divided bone portion 52 in the at least one (in the example of the figure, all) discontinuous bone portion 2BB rub ​​against each other. As a result, when the porous structure 1 is compressively deformed in a predetermined load input direction ID, friction is generated between the first end face 51E of the first divided bone portion 51 and the second end face 52E of the second divided bone portion 52 in at least one (preferably all) of the discontinuous bone portions 2BB. The "extension direction of the first divided bone portion 51" is a direction parallel to the central axis of the first divided bone portion 51 (shown by a dashed line in FIG. 11(b)). The "extension direction of the second divided bone portion 52" is a direction parallel to the central axis of the second divided bone portion 52 (shown by a dashed line in FIG. 11(b)). When the porous structure 1 is in its natural state, it is preferable that the first end face 51E and the second end face 52E face each other as shown in Fig. 11. When the porous structure 1 is in its natural state, the first end face 51E and the second end face 52E may be in a non-contact state with each other as in the example of Fig. 11, or may be in contact with each other. According to the fifth embodiment, in at least one (in the example shown in the figure, all) discontinuous bone portions 2BB, the first divided bone portion 51 has, at an end portion (tip portion) 51t in the extension direction of the first divided bone portion 51, a first end face 51E inclined with respect to a direction perpendicular to the extension direction of the first divided bone portion 51, and the second divided bone portion 52 has, at an end portion (tip portion) 52t in the extension direction of the second divided bone portion 52, a second end face 52E inclined with respect to a direction perpendicular to the extension direction of the second divided bone portion 52, and since the first end face 51E and the second end face 52E are approximately parallel to each other, the first end face 51E and the second end face 52E can be easily rubbed against each other, and a large contact area between the first end face 51E and the second end face 52E can be secured, and ultimately, a large amount of friction can be secured between the first side face 51S and the second side face 52S.

[0060] [Sixth embodiment of the porous structure] FIG. 12 is a diagram for explaining a porous structure 1 according to a sixth embodiment of the present invention. In the sixth embodiment, as in the first embodiment, the porous structure 1 is configured such that the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other when the porous structure 1 is compressively deformed in the predetermined load input direction ID. This allows friction to occur between the first divided bone portion 51 and the second divided bone portion 52 in the at least one (preferably all) discontinuous bone portion 2BB when the porous structure 1 is compressively deformed in the predetermined load input direction ID. In the sixth embodiment, similarly to the first embodiment, it is preferable that the first divided bone portion 51 and the second divided bone portion 52 each have a columnar shape. In the first embodiment (FIGS. 1 to 5), the extending direction of the first divided bone portion 51 and the extending direction of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB are parallel to each other. In contrast, in the sixth embodiment (FIG. 12), the extending direction of the first divided bone portion 51 and the extending direction of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB are non-parallel to each other. The porous structure 1 is configured such that, when compressively deformed in a predetermined load input direction ID, the first side surface 51S of the first divided bone portion 51 and the edge portion 52D of the second divided bone portion 52 rub against each other in at least one (preferably all) discontinuous bone portion 2BB (at this time, the edge portion 52D scratches the first side surface 51S, or the first side surface 51S scratches the edge portion 52D). As a result, when the porous structure 1 is compressed and deformed in a predetermined load input direction ID, friction occurs between the first side surface 51S and the edge portion 52D of at least one (preferably all) of the discontinuous bone portions 2BB. The "extension direction of the first divided bone portion 51" is a direction parallel to the central axis of the first divided bone portion 51 (shown by a dashed line in FIG. 12(b)). The "extension direction of the second divided bone portion 52" is a direction parallel to the central axis of the second divided bone portion 52 (shown by a dashed line in FIG. 12(b)). In this embodiment, the "first side surface 51S of the first divided bone portion 51" refers to a portion of the side surface of the first divided bone portion 51 that is configured to rub against the edge portion 52D of the second divided bone portion 52. Moreover, the "edge portion 52D" of the second divided bone portion 52 refers to the edge portion between the side surface of the second divided bone portion 52 and the end face of the second divided bone portion 52 on the tip portion 52t side. When the porous structure 1 is in its natural state, the first side surface 51S and the edge portion 52D may be in contact with each other as in the example of FIG. 12, or may be in a non-contact state with each other. According to the sixth embodiment, the extension direction of the first divided bone portion 51 and the extension direction of the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB are non-parallel to each other, and the porous structure 1 is configured so that, when compressed and deformed in a predetermined load input direction ID, in at least one (preferably all) discontinuous bone portion 2BB, the first side surface 51S of the first divided bone portion 51 and the edge portion 52D of the second divided bone portion 52 rub against each other (at this time, the edge portion 52D scratches the first side surface 51S), thereby ensuring a large amount of friction generated between the first side surface 51S and the edge portions 52D.

[0061] [Seventh embodiment of the porous structure] Fig. 13 to Fig. 15 are drawings for explaining the porous structure 1 according to the seventh embodiment of the present invention. Fig. 13 is a perspective view showing a part of the porous structure 1 according to the seventh embodiment of the present invention in a natural state without compressive deformation. Fig. 14 is a perspective view showing a part of the porous structure 1 of Fig. 13 in a state in which each bridge portion 23 described below is stretched for convenience. Fig. 15 is a perspective view showing the porous structure 1 of Fig. 13 in a state in which it is compressively deformed in a predetermined load input direction ID. In the first embodiment (FIGS. 1 to 5), as described above, the porous structure 1 is configured such that the first divided bone portion 51 and the second divided bone portion 52 in at least one (preferably all) discontinuous bone portion 2BB rub ​​against each other when the porous structure 1 is compressively deformed in the predetermined load input direction ID. In contrast, in the seventh embodiment (FIGS. 13 to 15), the porous structure 1 is configured such that two or more of the cell partitions 21 (specifically, adjacent cell partitions 21 in the two or more cell partitions 21) among the multiple cell partitions 21 included in the skeleton 2 interfere with each other when the porous structure 1 is compressively deformed in the predetermined load input direction ID. More specifically, when the porous structure 1 is compressively deformed in the predetermined load input direction ID, multiple portions in the two or more cell partitions 21 that were previously in a non-contact state come into contact with each other (immediately after the collision, the multiple portions may remain in contact and not move, or may move while in contact). As a result, when the porous structure 1 is compressed and deformed in a predetermined load input direction ID, friction occurs between the two or more cell partitions 21. In the first embodiment (FIGS. 1 to 5), as described above, each annular portion 211 is shared by a pair of cell partitions 21 adjacent to the annular portion 211 (i.e., a pair of cell partitions 21 sandwiching the annular portion 211 therebetween), in other words, a pair of adjacent cell partitions 21 share one annular portion 211. On the other hand, in the example of FIGS. 13 to 15, a pair of adjacent cell partitions 21 configured to interfere with each other do not share one annular portion 211, but each have a separate annular portion 211 in the adjacent portions (FIG. 14), and are configured so that the pair of annular portions 211 interfere with (abut against) each other. When the porous structure 1 is in its natural state, it is preferable that the multiple portions (a pair of annular portions 211 in the example of FIGS. 13 to 15) configured to interfere with each other face each other in a non-contact state. In the examples of Figures 13 to 15, each of the multiple cell partitions 21 provided in the skeletal portion 2 is a cell partition 21A that does not have a discontinuous bone portion 2BB, but some or all of the multiple cell partitions 21 provided in the skeletal portion 2 may be a cell partition 21B that has one or more discontinuous bone portions 2BB in any of the embodiments described in this specification. The seventh embodiment also provides the same effects as the first embodiment.

[0062] In the seventh embodiment, it is preferable that the skeleton 2 further includes one or more bridge portions 23 that connect the two or more cell partition portions 21 that are configured to interfere with each other. This allows the two or more cell partition portions to be integrated together via the bridge portions 23. Furthermore, when the porous structure 1 is in its natural state, the bridge portions 23 can maintain the positional relationship between the two or more cell partition portions 21 as intended. In addition, the porous structure 1 can be easily shaped by a 3D printer. Each bridge portion 23 is preferably configured in a columnar shape. From the viewpoint of facilitating deformation of bridge portion 23 and thus facilitating interference between the two or more cell partition portions 21, the cross-sectional area of ​​each bridge portion 23 (cross-sectional area in a direction perpendicular to the central axis of bridge portion 23) is preferably smaller than the minimum cross-sectional area of ​​bone portion 2B, but may be equal to or larger than the minimum cross-sectional area of ​​bone portion 2B. 13 to 15, each bridge portion 23 connects a pair of joint portions 2J in a pair of adjacent cell partitions 21 (FIG. 14). This enables each bridge portion 23 to more stably maintain the positional relationship between the pair of cell partitions 21 when the porous structure 1 is in its natural state. However, each bridge portion 23 may connect any portion of a pair of adjacent cell partitions 21.

[0063] The above-described embodiments may be combined as appropriate. For example, the porous structure 1 may employ the configurations of the discontinuous bone portions 2BB in different embodiments among the first to sixth embodiments, in the plurality of different discontinuous bone portions 2BB. Furthermore, the porous structure 1 may have both the configuration of the discontinuous bone portion 2BB in one or more of the first to sixth embodiments and the configuration in the seventh embodiment. Furthermore, in the same single discontinuous bone portion 2BB of the porous structure 1, the multiple protrusions P in the third embodiment may be applied to the first side surface 51S and / or the second side surface 52S in the first, second and fourth embodiments, or may be applied to the first end surface 51E and / or the second end surface 52E in the fifth embodiment, or may be applied to the first side surface 51S in the sixth embodiment.

[0064] [Eighth embodiment of the porous structure] 16 is a diagram for explaining the porous structure 1 according to the eighth embodiment of the present invention. The configuration explained in the eighth embodiment can be suitably applied to the porous structures 1 according to the above-mentioned first to seventh embodiments. In this embodiment, the porous structure 1 includes, in addition to a skeleton 2, one or more membranes 3. The membrane 3 extends on an imaginary plane V1 defined by the annular inner peripheral edge 2111 of the annular portion 211, thereby covering the imaginary plane V1 defined by the annular portion 211. In the porous structure 1 of the example of FIG. 16, at least one of the imaginary planes V1 constituting the skeleton portion 2 is covered with the membrane 3. The membrane 3 is made of the same material as the skeleton portion 2 and is configured integrally with the skeleton portion 2. In the example of FIG. 16, the membrane 3 is configured to be flat. However, the membrane 3 may be configured to be non-flat (for example, curved (curved)). It is preferable that the membrane 3 has a thickness smaller than the width W0 (FIG. 4) of the continuous bone portion 2BA. The membrane 3 prevents the two cell holes C sandwiching the virtual surface V1 from communicating with each other through the virtual surface V1, and ventilation through the virtual surface V1 is not possible, which ultimately reduces the air permeability of the porous structure 1 as a whole. By adjusting the number of virtual surfaces V1 that constitute the porous structure 1 that are covered with the membrane 3, the air permeability of the porous structure 1 as a whole can be adjusted, and various air permeability levels can be achieved according to requirements. It is not preferable that all of the virtual surfaces V1 that constitute the porous structure 1 are covered with the membrane 3; in other words, it is preferable that at least one of the virtual surfaces V1 that constitute the porous structure 1 is not covered with the membrane 3 and is open. As described above, conventional porous structures are manufactured through a process of foaming by chemical reaction, and therefore it is difficult to form the membranes in the communication holes that connect the cells with each other in the desired positions and number. When manufacturing the porous structure 1 with a 3D printer as in this example, it is possible to reliably form the membranes 3 in the desired positions and number by including information on the membranes 3 in advance in the 3D printing data read into the 3D printer. At least one of the small imaginary surfaces V1S constituting the skeleton 2 may be covered with the film 3. And / or at least one of the large imaginary surfaces V1L constituting the skeleton 2 may be covered with the film 3. When the skeletal portion 2 has discontinuous bone portions 2BB, from the viewpoint of preventing the membrane 3 from impeding the rubbing action of the discontinuous bone portions 2BB, it is preferable that each membrane 3 covers a virtual surface V1 defined by an annular portion 211 that does not have a discontinuous bone portion 2BB (i.e., an annular portion 211 in which all bone portions 2B are continuous bone portions 2BA).

[0065] [Seat pad with porous structure] As described above, the porous structure 1 according to each embodiment of the present invention can be used in a seat pad (particularly a vehicle seat pad). Hereinafter, with reference to FIG. 17, an example of a seat pad 302 that may include the porous structure 1 according to any embodiment of the present invention will be described. FIG. 17 is a perspective view that shows a schematic example of a vehicle seat 300 including a seat pad 302 (vehicle seat pad) that can be made of the porous structure 1 according to various embodiments of the present invention. As shown by the dashed line in FIG. 17, the vehicle seat 300 includes a cushion pad 310 for a seated person to sit on and a back pad 320 for supporting the back of the seated person. The cushion pad 310 and the back pad 320 are each composed of a seat pad 302. Hereinafter, the cushion pad 310 or the back pad 320 may be simply referred to as the "seat pad 302". The cushion pad 310 and the back pad 320 may each be composed of the porous structure 1 of any embodiment described in this specification. In addition to the seat pads 302 constituting the cushion pad 310 and the back pad 320, the vehicle seat 300 may include, for example, a skin 330 covering the front side (seater side) of the seat pad 302, a frame (not shown) supporting the cushion pad 310 from below, a frame (not shown) installed on the back side of the back pad 320, and a headrest 340 installed on the upper side of the back pad 320 to support the head of the seated person. The surface layer 330 is made of, for example, a breathable material (such as cloth). In the example of Fig. 17, the cushion pad 310 and the back pad 320 are configured separately from each other, but they may be configured integrally with each other. In addition, in the example of FIG. 17, the headrest 340 is configured as a separate body from the back pad 320, but the headrest 340 may be configured as an integral body with the back pad 320. In this specification, as shown in Figure 17, the directions "up," "down," "left," "right," "front," and "rear" when viewed from a person seated in the vehicle seat 300 (and thus the seat pad 302) are simply referred to as "up," "down," "left," "right," "front," and "rear," respectively.

[0066] The cushion pad 310 has a main pad portion 311 configured to support the buttocks and thighs of a seated person from below, and a pair of side pad portions 312 located on both the left and right sides of the main pad portion 311, raised above the main pad portion 311, and configured to support the seated person from both the left and right sides. The main pad portion 311 is made up of a lower thigh portion 311t configured to support the thighs of the seated person from below, and a lower buttock portion 311h located behind the lower thigh portion 311t and configured to support the buttocks of the seated person from below.

[0067] The back pad 320 has a main pad portion 321 configured to support the back of the seated person from the rear side, and a pair of side pad portions 322 located on both the left and right sides of the main pad portion 321, protruding forward more than the main pad portion 321, and configured to support the seated person from both the left and right sides.

[0068] In this specification, the "extension direction (LD) of the seat pad (302)" refers to a direction perpendicular to the left-right direction and thickness direction (TD) of the seat pad 302, and in the case of the cushion pad 310, refers to the front-rear direction (FIG. 17), and in the case of the back pad 320, refers to the direction in which the main pad portion 321 extends from the lower surface to the upper surface of the main pad portion 321 of the back pad 320 (FIG. 17). In addition, the "thickness direction (TD) of the seat pad (302)" refers to the up-down direction in the case of the cushion pad 310 (FIG. 17), and in the case of the back pad 320, it refers to the direction in which the main pad portion 321 of the back pad 320 extends from the surface (front surface) FS on the side of the seated person to the back surface BS (FIG. 17). Moreover, the "seat occupant side surface (front surface, FS)" of the seat pad (302) refers to the upper surface in the case of the cushion pad 310 (FIG. 17), and refers to the front surface in the case of the back pad 320 (FIG. 17). The "back surface (BS)" of the seat pad (302) is the surface opposite to the seat occupant side surface (FS) of the seat pad (302), and refers to the lower surface in the case of the cushion pad 310 (FIG. 17), and refers to the rear surface in the case of the back pad 320 (FIG. 17). The "side surface (SS)" of the seat pad (302) is the surface between the seat occupant side surface (FS) and the back surface (BS) of the seat pad (302), and refers to any one of the front surface, rear surface, left surface, or right surface in the case of the cushion pad 310 (FIG. 17), and refers to any one of the lower surface, upper surface, left surface, or right surface in the case of the back pad 320 (FIG. 17).

[0069] It is preferable that the porous structure 1 is oriented so that the predetermined load input direction ID coincides with the thickness direction TD of the seat pad 302.

[0070] In the example shown in FIG. 17, the porous structure 1 constitutes the entirety of each of the cushion pad 310 and the back pad 320 of the seat pad 302. However, the porous structure 1 may constitute only one of the cushion pad 310, the back pad 320, and the headrest 340 of the seat pad 302. The porous structure 1 may constitute only a part of the cushion pad 310 of the seat pad 302, only a part of the back pad 320, and / or only a part of the headrest 340. This allows the size of the porous structure 1 to be reduced, and therefore it is possible to manufacture the porous structure 1 using a relatively small 3D printer. In this case, the cushion pad 310, the back pad 320, and the headrest 340 of the seat pad 302 may be constituted of a conventional general porous structure (foam) as described above by being manufactured through a process of foaming by chemical reaction in, for example, mold molding or slab molding. For example, although not shown, the cushion pad 310, the back pad 320, and / or the headrest 340 of the seat pad 302 may each include a plurality of cushion parts that are configured separately from each other, and only a portion (one or more) of the plurality of cushion parts may be constituted by the porous structure 1, and the other cushion parts may be constituted by a porous structure (foam) manufactured through a process of foaming by chemical reaction in, for example, mold molding or slab molding. More specifically, for example, the cushion pad 310, the back pad 320, and / or the headrest 340 of the seat pad 302 may each include an insert consisting of one or more porous structures 1, and a main body portion that is configured separately from the one or more inserts, has a recess for accommodating the one or more inserts, and is made of a porous structure (foam) manufactured through a process of foaming by chemical reaction, for example, in mold molding or slab molding. Alternatively, the cushion pad 310, the back pad 320, and / or the headrest 340 of the seat pad 302 may be composed of a plurality of cushion parts configured separately from each other, and each of the plurality of cushion parts may be composed of the porous structure 1. This also allows the size of the porous structure 1 to be reduced, and therefore it becomes possible to manufacture the porous structure 1 using a relatively small 3D printer. It is preferable that the porous structure 1 constitutes at least a part of the main pad portion 311 , 321 of the cushion pad 310 or the back pad 320 .

[0071] [Method for producing a porous structure] Next, a method for manufacturing the porous structure 1 of the present invention will be illustrated with reference to Fig. 18. The method described below is a method for manufacturing the porous structure 1 using a 3D printer, and can be suitably used for manufacturing the porous structure 1 of any embodiment described in this specification. Fig. 18 shows the process of manufacturing the porous structure 1 that constitutes the seat pad. First, three-dimensional shape data (for example, three-dimensional CAD data) representing the three-dimensional shape of the porous structure 1 is created in advance using a computer. Next, using a computer, the above three-dimensional shape data is converted into 3D printing data 500. The 3D printing data 500 is read into the control unit 410 of the 3D printer 400 when the modeling unit 420 of the 3D printer 400 performs modeling, and the control unit 410 is configured to cause the modeling unit 420 to model the porous structure 1. The 3D printing data 500 includes, for example, slice data representing the two-dimensional shape of each layer of the porous structure 1. Next, the porous structure 1 is modeled by a 3D printer 400. The 3D printer 400 may perform modeling using any modeling method, such as a photolithography method, a powder sintering lamination method, a fused deposition modeling (FDM) method, an inkjet method, etc. From the viewpoint of productivity, the photolithography method is preferable. FIG. 18 shows a state where modeling is performed by the photolithography method. The 3D printer 400 includes a control unit 410 including a CPU or the like, a modeling unit 420 that performs modeling under the control of the control unit 410, a support table 430 for placing an object to be modeled (i.e., the porous structure 1), and a container 440 that contains liquid resin LR, the support table 430, and the object. When the modeling unit 420 uses a photo-modeling method as in this example, the modeling unit 420 has a laser irradiator 421 configured to irradiate ultraviolet laser light LL. The container 440 is filled with liquid resin LR. When the liquid resin LR is hit by the ultraviolet laser light LL irradiated from the laser irradiator 421, it hardens and becomes a flexible resin. In the 3D printer 400 configured in this manner, the control unit 410 first reads the 3D modeling data 500, and then controls the modeling unit 420 to irradiate ultraviolet laser light LL based on the three-dimensional shape contained in the read 3D modeling data 500, thereby sequentially modeling each layer. After the modeling by the 3D printer 400 is completed, the model is removed from the container 440. As a result, the porous structure 1 is finally obtained as the model. By manufacturing the porous structure 1 using a 3D printer, the porous structure 1 can be realized simply, precisely, and as desired in a single process. When the porous structure 1 is made of resin, the porous structure 1 as a molded object may be heated in an oven after the molding by the 3D printer 400 is completed. In this case, the bonds between the layers constituting the porous structure 1 are strengthened, and the anisotropy of the porous structure 1 can be reduced, thereby further improving the cushioning properties of the porous structure 1. Furthermore, when the porous structure 1 is made of rubber, the porous structure 1 as a shaped object may be vulcanized after the shaping by the 3D printer 400 is completed. [Industrial Applicability]

[0072] The porous structure and the method for manufacturing the porous structure of the present invention are suitable for use in cushioning materials, for example, in any vehicle seat and any vehicle seat pad (seat pad), and are particularly suitable for use in vehicle seats and vehicle seat pads. [Explanation of symbols]

[0073] 1: Porous structure, 2: Skeleton, 2B: bone portion, 2Be: end portion of bone portion, 2BA: continuous bone portion, 2BB: discontinuous bone portion, 51: first divided bone portion, 51t: tip portion, 51r: base portion, 51S: first side surface, 511: wide side surface, 512: narrow side surface, 51E: first end surface, 52: second divided bone portion, 52t: tip portion, 52r: base portion, 52S: second side surface, 521: wide side surface, 522: narrow side surface, 52E: second end surface, 52D: edge portion, P: protrusion, 2J: Joint part, 21, 21A, 21B: cell partition portion, 211: annular portion, 211L: large annular portion, 211S: small annular portion, 2111: inner peripheral edge portion of the annular portion, 23: Hashibe, 3: Membrane, C: cell hole, O: skeleton line, V1: virtual surface, V1L: large virtual surface, V1S: small virtual surface, ID: predetermined load input direction, 300: Vehicle seats, 302: Seat pad, 310: Cushion pad, 311: Main pad part (seating part), 311t: Lower thigh part, 311h: Lower buttocks part, 312: Side pad part, 320: back pad, 321: main pad section, 322: side pad section, 330: Epidermis, 340: Headrest, FS: surface facing the seated person (front surface), SS: side surface, BS: back surface, TD: thickness direction, LD: extension direction, 400: 3D printer, 410: control unit, 420: modeling unit, 421: laser irradiator, 430: support stand, 440: container, LL: ultraviolet laser light, LR: liquid resin, 500: 3D modeling data

Claims

1. A porous structure made of flexible resin or rubber, The porous structure has a skeleton throughout its entirety, The skeleton portion is A plurality of bones; a plurality of connecting portions each connecting an end portion of the plurality of bone portions to each other; It is equipped with the porous structure is configured such that a plurality of portions of the skeleton interfere with each other when the porous structure is compressively deformed in a predetermined load input direction, At least one of the plurality of bone portions is a discontinuous bone portion including a first divided bone portion and a second divided bone portion, each of which is divided from the other. The porous structure is configured such that the first divided bone portion and the second divided bone portion in the discontinuous bone portion rub against each other when the porous structure is compressively deformed in the specified load input direction.

2. In the discontinuous bone portion, The first split bone portion has a first side surface, The second split bone portion has a second side surface, The porous structure described in claim 1, wherein the porous structure is configured such that, when compressed and deformed in the specified load input direction, the first side surface of the first split bone portion and the second side surface of the second split bone portion in the discontinuous bone portion rub against each other.

3. The porous structure according to claim 2 , wherein at least one of the first divided bone portion and the second divided bone portion in the discontinuous bone portion is strip-shaped.

4. The porous structure according to claim 2 , wherein at least one of the first side surface and the second side surface of the discontinuous bone portion has a plurality of protrusions.

5. The porous structure described in claim 2, wherein in the discontinuous bone portion, the second side is configured to surround the first side along the circumferential direction of the first split bone portion when the porous structure is compressively deformed in the specified load input direction.

6. In the discontinuous bone portion, the first divided bone portion has a first end surface inclined with respect to a direction perpendicular to the extension direction of the first divided bone portion at an end portion in the extension direction of the first divided bone portion, the second divided bone portion has a second end surface at an end in an extension direction of the second divided bone portion, the second end surface being inclined with respect to a direction perpendicular to the extension direction of the second divided bone portion, the first end surface and the second end surface are substantially parallel to each other, The porous structure according to claim 1, wherein the porous structure is configured such that, when compressed and deformed in the specified load input direction, the first end face of the first split bone portion in the discontinuous bone portion and the second end face of the second split bone portion rub against each other.

7. The porous structure according to claim 1 , wherein an extension direction of the first divided bone portion and an extension direction of the second divided bone portion in the discontinuous bone portion are non-parallel to each other.

8. A porous structure made of flexible resin or rubber, The porous structure has a skeleton throughout its entirety, The skeleton portion is A plurality of bones; a plurality of connecting portions each connecting an end portion of the plurality of bone portions to each other; It is equipped with the porous structure is configured such that a plurality of portions of the skeleton interfere with each other when the porous structure is compressively deformed in a predetermined load input direction, the skeleton has a plurality of cell partitions that partition cell pores therein, Each of the cell partitions is composed of a plurality of the bone portions and a plurality of the joint portions, the porous structure is configured such that, when compressively deformed in the predetermined load input direction, two or more of the plurality of cell partitions interfere with each other, The scaffold further comprises one or more bridges connecting the two or more cell compartments.

9. the skeleton has a plurality of cell partitions that partition cell pores therein, Each of the cell partitions has a plurality of annular portions each configured in an annular shape, the plurality of annular portions constituting the cell partition are connected to each other such that imaginary planes defined by the respective inner circumferential side edges do not intersect with each other, Each of the annular portions is composed of a plurality of the bone portions and a plurality of the connection portions, Each of the virtual surfaces is substantially flat, The porous structure according to any one of claims 1 to 8, wherein the cell holes are defined by the plurality of annular portions and a plurality of the imaginary surfaces defined by the plurality of annular portions, respectively.

10. the plurality of annular portions constituting the cell partition include one or more small annular portions and one or more large annular portions, Each of the small annular portions defines a small substantially flat imaginary surface by its inner peripheral edge portion, The porous structure according to claim 9 , wherein each of the large annular portions defines, by its inner peripheral edge, a large imaginary surface which is substantially flat and has an area larger than that of the small imaginary surface.

11. The porous structure according to claim 10 , wherein the small imaginary surface and the large imaginary surface have different shapes.

12. The porous structure according to any one of claims 9 to 11, wherein each of the cell holes has a shape of a substantially Kelvin tetrahedron.

13. The porous structure according to any one of claims 1 to 12, which is used as a cushioning material.

14. The porous structure according to any one of claims 1 to 13, wherein the porous structure is formed by a 3D printer.

15. A method for producing a porous structure, comprising the steps of: producing the porous structure according to any one of claims 1 to 13 using a 3D printer.

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