Shoe member

Abstract

Provided is a shoe member constituted by a three-dimensional lattice structure which has a plurality of support columns and a plurality of connection parts that connect the support columns, wherein: the three-dimensional lattice structure is constituted by a resin composition; the three-dimensional lattice structure is provided with a high-density part in the support columns and / or the connection parts; the high-density part of the support columns has a higher density than the apparent density of the support columns and is a cylindrical body constituting a surface layer part of the support columns; and the high-density part of the connection parts has a higher density than the apparent density of the connection parts, and is a layer-like body constituting a surface layer part of the connection parts.

Description

Shoe member Cross-reference to related applications

[0001] This application claims the priority of Japanese Patent Application No. 2024-229301, and is incorporated by reference into the description of this application.

[0002] This disclosure relates to shoe members.

[0003] Conventionally, it has been considered to use a three-dimensional structure composed of plate-like partition bodies as a buffer (see Patent Document 1 below). Regarding such a three-dimensional structure, it has been considered to use a three-dimensional lattice structure including cell elements including a plurality of struts as a shoe member (see Patent Document 2 below).

[0004] International Publication No. 2017 / 208979 Japanese Patent Application Laid-Open No. 2017-12751

[0005] [[ID=第十七]] In the three-dimensional structure adopted for the shoe member, when compressed, the partition bodies and struts constituting the three-dimensional structure may collide with each other, generating an excessively high repulsive force. Therefore, when this type of three-dimensional structure is adopted, it is difficult to exhibit good cushioning performance in the shoe. An object of the present invention is to provide a shoe member with improved cushioning performance.

[0006] The shoe member according to one aspect of this disclosure is composed of a three-dimensional lattice structure including a plurality of struts and a plurality of connecting portions connecting the struts, the three-dimensional lattice structure is composed of a resin composition, and the three-dimensional lattice structure has at least one of the struts and the connecting portions provided with a high-density portion, the high-density portion of the strut has a density higher than the apparent density of the strut and is a cylindrical body constituting the surface layer portion of the strut, and the high-density portion of the connecting portion has a density higher than the apparent density of the connecting portion and is a layer-like body constituting the surface layer portion of the connecting portion.

[0007] Figure 1A is a schematic perspective view of a shoe equipped with a shoe component according to one embodiment. Figure 1B is a schematic perspective view showing a part of a three-dimensional lattice structure according to one embodiment. Figure 2A is a schematic perspective view showing an example of a lattice used to construct a three-dimensional lattice structure. Figure 2B is a schematic perspective view showing the unit structure of a three-dimensional lattice structure according to one embodiment. Figure 2C is a schematic perspective view showing the shape of the unit structure of a three-dimensional lattice structure according to one embodiment. Figure 3 is a schematic perspective view showing another embodiment of the unit structure of a three-dimensional lattice structure. Figure 4 is a schematic cross-sectional view showing a cross-section of the support column of a three-dimensional lattice structure according to one embodiment (cross-sectional view taken along the line IV-IV in Figure 2B). Figure 5 is a schematic cross-sectional view showing a cross-section of the connection part of a three-dimensional lattice structure according to one embodiment (cross-sectional view taken along the line V-V in Figure 2B). Figure 6A is a schematic perspective view showing the positional relationship of the support columns at the connection part of a three-dimensional lattice structure according to one embodiment. Figure 6B is a schematic plan view showing the positional relationship of the support columns at the connection part of a three-dimensional lattice structure according to one embodiment. Figure 7 is a schematic cross-sectional view of a support column with a hollow section inside. Figure 8A is a schematic plan view showing a support column and a connecting section with ribs. Figure 8B is a schematic cross-sectional view of a support column with ribs (cross-sectional view taken along the line B-B in Figure 8A). Figure 9 is a schematic perspective view of a support column with ribs. Figure 10 is a schematic cross-sectional view of a support column with ribs inside. Figure 11A is a schematic cross-sectional view showing a support column with a foamed interior and ribs. Figure 11B is a schematic cross-sectional view showing a support column with a foamed interior and ribs. Figure 12 is a schematic cross-sectional view of a support column with an elliptical cross-sectional shape. Figure 13 is a schematic cross-sectional view of a support column where the thickness of the high-density section differs in the circumferential direction. Figure 14 is a schematic cross-sectional view of a support column with three ribs so that the protruding direction is radial. Figure 15 is a diagram showing a model of a three-dimensional lattice structure used for evaluation in the embodiment. Figure 16 is a diagram showing the evaluation results using the model in Figure 15. Figure 17 shows the relationship between the degree of foaming inside a three-dimensional lattice structure and its rebound behavior in response to load.

[0008] The following describes one embodiment of a shoe component with reference to the figure. First, the shoe component of one embodiment will be described with reference to shoe 1, which is an example shown in Figure 1A. In the following description, the vertical direction may be referred to as the "height direction DZ," etc. Also, in the following description, among the directions along the horizontal plane, the direction connecting the heel and toe of shoe 1 may be referred to as the "foot length direction DX," etc. And, in the following description, among the directions along the horizontal plane, the direction perpendicular to the foot length direction DX may be referred to as the "foot width direction DY," etc.

[0009] In this disclosure, shoe 1 is a sports shoe. Shoe 1 comprises a sole 2 that supports the wearer's foot from below and an upper 3 that covers the wearer's foot from the top. The sole 2 and upper 3, as illustrated in the figure, are each composed of a three-dimensional lattice structure 10. In this disclosure, shoe 1 may have a shoe body comprising the sole 2 and the upper 3, and an insole that is detachably provided to the shoe body. In this disclosure, the shoe component composed of the three-dimensional lattice structure 10 may be the insole. In this disclosure, the cushioning performance of the shoe component can be improved by having the three-dimensional lattice structure 10, as will be described in detail below.

[0010] The three-dimensional lattice structure 10 that constitutes the shoe sole 2 illustrated in Figure 1A comprises a plurality of support columns 11 and a plurality of connecting parts 12 that connect the support columns 11 to each other, as shown in Figure 1B. The three-dimensional lattice structure 10 in this disclosure is made of a resin composition. The three-dimensional lattice structure 10 is made of unit cells as shown in Figure 2A. In the three-dimensional lattice structure 10, a plurality of unit cells are connected to each other. The three-dimensional lattice structure 10 is made by arranging the unit cells in a three-dimensional direction. In the three-dimensional lattice structure 10, a unit structure C is defined by the support columns 11 and connecting parts 12 of the plurality of unit cells. The three-dimensional lattice structure 10 is made up of a state in which the unit structures C having a parallelepiped shape are repeatedly arranged. The unit cell may be a simple cubic lattice, a body-centered cubic structure, a face-centered cubic lattice, a diamond lattice, an octahedral lattice, etc.

[0011] The three-dimensional lattice structure 10 is composed of repeated unit structures C, each consisting of multiple support columns 11 and multiple connecting parts 12. In one embodiment, the unit structure C has the shape of a rhombic dodecahedron Cx, as shown in Figures 2B and 2C.

[0012] In one embodiment, the three-dimensional lattice structure 10 includes a row of unit structures C arranged linearly so as to extend in the leg length direction DX. The three-dimensional lattice structure 10 includes a plurality of row of unit structures extending in the leg length direction DX. The direction in which the row of unit structures extends may be parallel to the leg length direction DX. The direction in which the row of unit structures extends does not have to be parallel to the leg length direction DX. The direction in which the row of unit structures extends may be slightly inclined in the up, down, left, and right directions with respect to the leg length direction DX. The shape of the row of unit structures may be linear or curved. The plurality of row of unit structures are arranged closely together in the leg width direction DY. The plurality of row of unit structures arranged in the leg width direction DY constitute a layer of unit structures. In one embodiment, the dimension of the layer of unit structures in the height direction DH is equal to the height of one unit structure C. In other words, the layer of unit structures in one embodiment is composed of a plurality of unit structures arranged in the leg length direction DX and the leg width direction DY. In one embodiment, the three-dimensional lattice structure 10 includes a plurality of unit structural layers. In the three-dimensional lattice structure 10, the plurality of unit structural layers are stacked in the height direction DZ. The sole 2, which is a three-dimensional lattice structure 10 composed of repeating unit structures C in this way, can easily disperse the load when a load is applied by the user's foot.

[0013] The three-dimensional lattice structure 10 may have a one-dimensional structure (columns) in which a normalized unit structure is repeated in at least one direction, a two-dimensional structure (layers) in which the structure is repeated in both a second direction intersecting the first direction and the first direction, or a three-dimensional structure (laminated structure) in which the structure is repeated in a third direction intersecting a virtual plane including the first and second directions, as the overall structure or a partial structure. Incorporating such a structure into the three-dimensional lattice structure 10 makes it easier to design shoe components. In other words, incorporating such a structure into the three-dimensional lattice structure 10 makes it easier to manufacture shoe components of various shapes.

[0014] In space-filling with rhombic dodecahedrons Cx, one vertex CN is shared by six rhombic dodecahedrons Cx, and one edge SD is shared by three rhombic dodecahedrons Cx. Therefore, in the three-dimensional lattice structure 10 of this disclosure, one connection part 12 is shared by six unit structures C, and one support column 11 is shared by three unit structures C. A rhombic dodecahedron Cx has 24 edges SD and 14 vertices CN. Therefore, considering only one unit structure C, the three-dimensional lattice structure 10 is composed of repeating unit structures C, each consisting of 24 support columns 11 and 14 connection parts 12.

[0015] The rhombic dodecahedron Cx is a parallelepiped. Therefore, the unit structure C in this disclosure can fill space without gaps together with other unit structures C having a common shape. The shape of the unit structure C may be a parallelepiped, a parallelepiped prism, a long rhombic dodecahedron, or a truncated octahedron. The three-dimensional lattice structure 10 may consist of two types of unit structures arranged alternately in one direction. The three-dimensional lattice structure 10 may consist of three types of unit structures, each repeated in one direction with other unit structures in between.

[0016] If the three-dimensional lattice structure 10 includes repetitions of two types of unit structures, the shape of each unit structure can be, for example, a regular tetrahedron and a regular octahedron. The two types of unit structures may be, for example, a regular tetrahedron and a truncated tetrahedron. The two types of unit structures may be, for example, a regular octahedron and a truncated hexahedron. The two types of unit structures may be, for example, a regular octahedron and a cuboctahedron. The two types of unit structures may be, for example, a rhombic truncated cuboctahedron and a regular octagonal prism.

[0017] If the three-dimensional lattice structure 10 includes a repetition of three types of unit structures, the shape of each unit structure can be, for example, a truncated tetrahedron, a truncated octahedron, and a cuboctahedron. The three types of unit structures can also be, for example, a truncated tetrahedron, a truncated hexahedron, and a rhombic truncated cuboctahedron. The three types of unit structures can also be, for example, a regular tetrahedron, a cube, and a rhombic cuboctahedron. The three types of unit structures can also be, for example, a cube, a cuboctahedron, and a rhombic cuboctahedron. The three types of unit structures can also be, for example, a cube, a truncated octahedron, and a rhombic truncated cuboctahedron. The three-dimensional lattice structure 10 can also be, for example, made up of four shapes: a cube, a truncated hexahedron, a rhombic truncated cuboctahedron, and a regular octagonal prism.

[0018] In the three-dimensional lattice structure 10 shown in Figure 2A and the like, the connecting portion 12 is a node corresponding to a vertex CN of the rhombic dodecahedron Cx. In this disclosure, the connecting portion 12 of the three-dimensional lattice structure 10 may be plate-like, for example, as shown in Figure 3, corresponding to some faces PL of the rhombic dodecahedron Cx.

[0019] In the three-dimensional lattice structure 10 of this disclosure, at least one of the multiple support columns 11 and the multiple connecting parts 12 has different densities in its surface and interior. The multiple support columns 11 in this disclosure have high-density parts with a density higher than their apparent density. The apparent density of a support column 11 is calculated by separating the support column 11 from the three-dimensional lattice structure 10, measuring its mass with an electronic balance, and measuring its apparent volume with a three-dimensional measuring machine. More specifically, the apparent volume of a support column 11 is determined as the volume of the solid enclosed by the outer surface of the support column 11 and the cut surface when separating it from the three-dimensional lattice structure 10. That is, if the support column 11 is a hollow body with a cavity inside, the apparent volume of the support column 11 also includes the volume of the cavity. The apparent density of the connecting parts 12 is measured in the same way. Apparent density = mass / apparent volume

[0020] 0 As shown in Figure 4, in one embodiment, the support column 11 has a circular cross-sectional shape in a plane perpendicular to the longitudinal direction DL of the support column 11. The support column 11 is cylindrical. The cross-sectional shape of the support column 11 may be a polygon such as a triangle or a quadrilateral. The support column 11 may be a prismatic shape. The cross-sectional shape of the support column 11 may be irregular.

[0021] In one embodiment, the column 11 has different densities at the center and on the outside in the radial direction Dd. In one embodiment, the interior of the column 11 is made of resin foam. As shown in the figure, the high-density portion 11A is arranged to constitute the surface layer of the column 11. The high-density portion 11A that constitutes the surface layer of the column 11 may be made of resin foam with a lower degree of foaming than the interior. In one embodiment, the high-density portion 11A is a non-foamed material made of a non-foamed resin composition. The high-density portion 11A of the column 11 illustrated in the figure is a cylindrical body extending in the longitudinal direction DL of the column 11. The thickness of the high-density portion 11A in the radial direction Dd is uniform in the circumferential direction Dr. The column 11 has a low-density portion 11B made of resin foam. The low-density portion 11B has a lower density than the high-density portion 11A and a lower density than the apparent density of the column 11. The low-density section 11B is provided so as to be in contact with the inner circumferential surface of the high-density section 11A, which is a cylindrical body, from the inside.

[0022] In one embodiment of the three-dimensional lattice structure 10, as shown in Figure 5, the high-density portion 12A is arranged in the connection portion 12 to constitute the surface layer. The high-density portion 12A in the connection portion 12 is a layered body. Similar to the support column 11, the connection portion 12 also has a low-density portion 12B made of resin foam on the central side of the high-density portion 12A. The connection portion 12 in the embodiment illustrated in Figure 5 has a core-shell structure. The core portion of the connection portion 12 is a low-density portion 12B made of resin foam. The shell portion of the connection portion 12 is a high-density portion 12A made of non-foamed material.

[0023] In the three-dimensional lattice structure 10, the non-foamed material constituting the surface layer of one support column 11 is continuous in the longitudinal direction DL of the support column 11 and continues to the non-foamed material of other support columns 11 via the non-foamed material of the connecting portion 12. That is, in one embodiment of the three-dimensional lattice structure 10, a plurality of support columns 11 are connected to a single connecting portion 12. The plurality of support columns 11 include a first support column 11 and a second support column 11. The high-density portion 11A of the first support column 11 and the high-density portion 11A of the second support column 11 are continuous via the high-density portion 12A of the connecting portion 12. In one embodiment of the three-dimensional lattice structure 10, the high-density portions 11A of the plurality of support columns 11 and the high-density portions 12A of the plurality of connecting portions 12 may be connected throughout the entire three-dimensional lattice structure 10.

[0024] In one embodiment, the resin foam constituting the central part of one support column 11 in the three-dimensional lattice structure 10 is continuous in the longitudinal direction DL of the support column 11. In one embodiment of the three-dimensional lattice structure 10, the resin foam constituting the central part of one support column 11 is continuous to the resin foam of other support columns 11 via the resin foam of the connecting portion 12. That is, in one embodiment of the three-dimensional lattice structure 10, a plurality of support columns 11, including a first support column 11 and a second support column 11, are connected to a single connecting portion 12, and the low-density portion 11B of the first support column 11 and the low-density portion 11B of the second support column 11 may be continuous via the low-density portion 12B of the connecting portion 12. In the three-dimensional lattice structure 10, the low-density portions 11B of the plurality of support columns 11 and the low-density portions 12B of the plurality of connecting portions 12 may be connected throughout the entire three-dimensional lattice structure 10.

[0025] One or both of the resin foam constituting the central part of the support column 11 and the resin foam constituting the central part of the connecting part 12 may be open-cell foam having open cells. In one embodiment, the open-cell ratio of the open-cell foam is 50% or more. The open-cell ratio may be 60% or more, 70% or more, or 80% or more. The open-cell ratio is determined on a cell-based basis. The open-cell ratio is calculated, for example, by cutting the support column 11 or the connecting part 12 and counting the number of cells in the resin foam observed in the cross-section that are in communication with adjacent cells. The cross-section is observed with a scanning electron microscope (SEM). The cross-section is photographed at a magnification of 200x. The open-cell ratio is calculated by observing several cells (for example, 100) randomly selected from the obtained microscope photographs and counting the number of cells that are in communication with adjacent cells.

[0026] The support columns 11 and connecting parts 12 are made of open-cell foam resin, allowing air to move within them through interconnected bubbles. The three-dimensional lattice structure 10 may have both support columns 11 and connecting parts 12 made of open-cell foam resin. The three-dimensional lattice structure 10 may allow air to move from one support column 11 connected to one connecting part 12 to another support column 11 through the connecting part 12. The three-dimensional lattice structure 10 may allow air to move throughout its entirety. The support columns 11 and connecting parts 12 may have ventilation holes that connect the external space to the open-cell foam. The ventilation holes may be provided in only one location, or in multiple locations on the three-dimensional lattice structure 10. A three-dimensional lattice structure 10 with ventilation holes can expel air contained in the resin foam to the outside when compressed, and the repulsive force against compressive force will be slower to manifest.

[0027] For purposes such as enabling the three-dimensional lattice structure 10 to exhibit high repulsive force, one or both of the resin foam constituting the central part of the support column 11 and the resin foam constituting the central part of the connecting part 12 may be made of closed-cell foam. The closed-cell ratio of the closed-cell foam is, for example, 50% or more. The closed-cell ratio of the closed-cell foam may be 60% or more, 70% or more, or 80% or more. The closed-cell ratio is obtained by subtracting the aforementioned open-cell ratio value from 100%.

[0028] The three-dimensional lattice structure 10 constituting the sole 2 includes a plurality of connection parts 12 to which a plurality of support columns 11 are connected. The plurality of connection parts 12 include a connection part 12 to which at least one of the plurality of support columns 11 is connected as an upward-extending support column 111 when the three-dimensional lattice structure 10 is arranged so that its thickness direction is the height direction DZ. The plurality of connection parts 12 include a connection part 12 to which at least one of the plurality of support columns 11 is connected as a downward-extending support column 112 when the three-dimensional lattice structure 10 is arranged so that its thickness direction is the height direction DZ. The plurality of connection parts 12 have a connection part to which both the upward-extending support column 111 and the downward-extending support column 112 are connected. One embodiment of the three-dimensional lattice structure 10 has a connection part 12 to which a plurality of upward-extending support columns 111 are connected. Furthermore, the upward-facing support 111 and downward-facing support 112 refer to support columns 11 that extend upward or downward, respectively, when viewed from a single connection point 12. Therefore, when two connection points 12 located separately in the vertical direction are connected by a single support column 11, the support column 11 is an upward-facing support 111 at the lower connection point 12, but a downward-facing support 112 at the upper connection point 12.

[0029] In a connection section 12 where multiple upward-facing support columns 111 are connected, the multiple upward-facing support columns 111 may be connected such that the distance between them increases as they extend upward. In one embodiment, as shown in Figure 6A, the multiple upward-facing support columns 111 extend from the connection section 12 so as to have the same elevation angle θ1 with respect to one of the virtual planes passing through the connection section 12. In one embodiment, the multiple upward-facing support columns 111 extend from the connection section 12 so as to have the same elevation angle θ1 with respect to a virtual plane P1 that intersects the height direction DZ and extends in the leg length direction DX and the leg width direction DY.

[0030] The elevation angle θ1 of the upward support column 111 may be, for example, 10 degrees or more. The elevation angle θ1 may be 15 degrees or more, 20 degrees or more, or 25 degrees or more. The elevation angle θ1 of the upward support column 111 may be, for example, 70 degrees or less. The elevation angle θ1 may be 60 degrees or less, or 50 degrees or less.

[0031] The connection point 12 to which multiple upward-facing support columns 111 are connected so that they share a common elevation angle θ1 may be only a part of the connection point 12 to which multiple upward-facing support columns 111 are connected. When the total number of connection points 12 to which multiple upward-facing support columns 111 are connected is taken as 100%, the number of connection points 12 that share a common elevation angle θ1 may be 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more.

[0032] The three-dimensional lattice structure 10 has a connection section 12 to which a plurality of downward-facing support columns 112 are connected. In one embodiment of the three-dimensional lattice structure 10, a plurality of downward-facing support columns 112 are connected to a connection section 12 to which a plurality of upward-facing support columns 111 are connected. A plurality of downward-facing support columns 112 may be connected to the connection section 12 such that the distance between them increases as they extend downward. In one embodiment of the three-dimensional lattice structure 10, at each of the plurality of connection sections 12, a plurality of downward-facing support columns 112 extend from the connection section 12 such that the distance between them increases as they extend downward. Preferably, the plurality of downward-facing support columns 112 extend from the connection section such that they have the same depression angle θ2 with respect to the virtual plane P1.

[0033] The downward angle θ2 of the downward support column 112 may be, for example, 10 degrees or more. The downward angle θ2 may be 15 degrees or more, 20 degrees or more, or 25 degrees or more. The downward angle θ2 of the downward support column 112 may be, for example, 70 degrees or less. The downward angle θ2 may be 60 degrees or less, or 50 degrees or less.

[0034] The connection point 12 to which multiple downward-facing support columns 112 are connected so that they share a common depression angle θ2 may be only a part of the connection point 12 to which multiple downward-facing support columns 112 are connected. When the total number of connection points 12 to which multiple downward-facing support columns 112 are connected is considered to be 100%, the number of connection points 12 that share a common depression angle θ2 may be 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more.

[0035] The connection point 12 to which multiple upward-facing support columns 111 with a common elevation angle θ1 and multiple downward-facing support columns 112 with a common depression angle θ2 are connected may be a part of all the connection points 12 to which the multiple upward-facing support columns 111 and the multiple downward-facing support columns 112 are connected. The connection point 12 to which both elevation angle θ1 and depression angle θ2 are common may be 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more of all the connection points 12 to which the multiple upward-facing support columns 111 and the multiple downward-facing support columns 112 are connected.

[0036] The elevation angle θ1 of the upward support 111 and the depression angle θ2 of the downward support 112 may or may not coincide.

[0037] In one embodiment, the virtual plane P1 may be a horizontal plane. In that case, the normal direction of the virtual plane P1 is the height direction DZ of the shoe 1. The height direction DZ is the direction in which the user's weight is applied to the sole 2, and is the direction in which a large load is applied. As shown in Figure 6B, in one embodiment, the three-dimensional lattice structure 10 is configured such that, when viewed from the height direction DZ, which is the direction in which the load is applied, a plurality of support columns 11 extend radially from a single connection part 12. In the three-dimensional lattice structure 10 in one embodiment, a plurality of upward support columns 111 and a plurality of downward support columns 112 connected to a single connection part 12 each extend radially from the connection part 12.

[0038] Each of the multiple downward-facing support columns 112 is positioned between adjacent upward-facing support columns 111 in the circumferential direction DC, where DC is defined as the direction along the circle centered on the connection portion 12 to which the upper end of the downward-facing support column 112 is connected.

[0039] Each of the multiple upward-facing support columns 111 and the multiple downward-facing support columns 112 is arranged at equal intervals in the circumferential direction DC. When the number of upward-facing support columns 111 connected to one connection part 12 is n (n≧2), adjacent upward-facing support columns 111 in the circumferential direction DC are arranged at an opening angle of (360 / n) degrees. In the embodiment shown in Figure 6B, two upward-facing support columns 111 and two downward-facing support columns 112 are connected to one connection part 12. In the embodiment shown in Figure 6B, the two upward-facing support columns 111 are connected to the connection part 12 at an opening angle of 180 degrees (360 degrees / 2). Also, in the embodiment shown in Figure 6B, the two downward-facing support columns 112 are connected to the connection part 12 at an opening angle of 180 degrees (360 degrees / 2).

[0040] In the embodiment shown in Figure 6B, each of the multiple downward-facing support columns 112 is located midway between two adjacent upward-facing support columns 111 in the circumferential direction DC. Therefore, adjacent downward-facing support columns 112 and upward-facing support columns 111 in the circumferential direction DC are connected to a single connection 12 at a 90-degree angle. Thus, in one embodiment of the three-dimensional lattice structure 10, the multiple support columns 11 extending from a single connection 12 are arranged to exhibit rotational symmetry with respect to the circumferential direction DC. That is, in one embodiment of the three-dimensional lattice structure 10, the number of multiple upward-facing support columns 111 extending from a single connection 12 is the same as the number of multiple downward-facing support columns 112 (n columns: n≧2), and these support columns 11 are connected to the connection 12 to exhibit rotational symmetry that is n times symmetric in the circumferential direction DC. As a result, the load applied to the three-dimensional lattice structure 10 is uniformly distributed.

[0041] In one embodiment, the cross-sectional shape of the upward support column 111 and the downward support column 112 in a plane perpendicular to the longitudinal direction DL is common at one point in the longitudinal direction DL and at another point different from the aforementioned point.

[0042] In other embodiments, each of the upward support column 111 and the downward support column 112 may have a cross-sectional shape in a plane orthogonal to the length direction DL that is different at one location in the length direction DL and at another location different from the said location. Each of the upward support column 111 and the downward support column 112 may have a shape such that the diameter changes in the length direction DL. Each of the upward support column 111 and the downward support column 112 may have a shape such that the diameter becomes thicker as it moves away from the connection portion 12. Each of the upward support column 111 and the downward support column 112 may have a shape such that the diameter becomes thinner as it moves away from the connection portion 12. Each of the upward support column 111 and the downward support column 112 may have a shape in which the middle portion in the length direction DL is thick and both end portions are thinner than the central portion. Each of the upward support column 111 and the downward support column 112 may have a shape in which both end portions in the length direction DL are thicker than the middle portion.

[0043] By changing the cross-sectional shape of the upward support column 111 or the downward support column 112 in the length direction DL, it becomes easy to exhibit the rigidity state and reduce the weight of the three-dimensional lattice structure 10.

[0044] In one embodiment, the support column 11 includes a high-density portion 11A and a low-density portion 11B made of a foam, and the high-density portion 11A is a cylindrical body that covers the low-density portion 11B. By having this high-density portion 11A, the support column 11 is excellent in rigidity. Also, in one embodiment, the connection portion 12 includes a high-density portion 12A and a low-density portion 12B made of a foam, and the high-density portion 12A is a layered body that covers the low-density portion 12B. By having this high-density portion 12A, the connection portion  12 is excellent in rigidity. Since the support column 11 and the connection portion 12 have the high-density portions 11A and 12A, the three-dimensional lattice structure 10 exhibits excellent repulsive force against the applied load.

[0045] When the three-dimensional lattice structure 10 constituting the shoe sole 2 is in use, a compressive load is applied from the height direction DZ. Even when the support columns and the connection portions are made of a non-foamed resin composition throughout, they exhibit high rigidity. However, when the three-dimensional lattice structure is composed of such support columns and connection portions, when compressed to a state where the support columns contact each other, the connection portions contact each other, or the support column and the connection portion contact each other, the repulsive force against the applied load suddenly becomes very high.

[0046] When the three-dimensional lattice structure 10 is compressed to a state where the struts 11 contact each other, the connection parts 12 contact each other, or the strut 11 and the connection part 12 contact each other, in the three-dimensional lattice structure 10 of the present disclosure, since the interior is a foam, the struts 11 and the connection parts 12 are more likely to be further compressed and deformed. Therefore, by adopting the three-dimensional lattice structure 10 of the present disclosure, a shoe member with improved cushioning properties can be provided. Further, in the three-dimensional lattice structure 10 in the aspect shown in FIG. 6B, a plurality of struts 11 extending from one connection part 12 are arranged so as not to overlap when viewed from the direction in which the load is applied (the height direction DZ in FIG. 6B). Therefore, in such an aspect, the cushioning property is further improved.

[0047] In the three-dimensional lattice structure 10 in the aspect shown in FIG. 6B, a plurality of struts 11 extending from one connection part 12 are arranged so as not to overlap vertically when viewed from the direction in which the load is applied (the height direction DZ in FIG. 6B). Therefore, in such an aspect, the cushioning property is further improved.

[0048] The connection part 12 where the upward strut 111 and the downward strut 112 that are connected are connected so as not to overlap vertically when viewed from the height direction DZ may be a part of the connection part 12 where the upward strut 111 and the downward strut 112 are connected. When the total number of the connection parts 12 where the upward strut 111 and the downward strut 112 are connected is taken as 100%, the connection part 12 where the upward strut 111 and the downward strut 112 are connected so as not to overlap may be 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more of them.

[0049] To improve cushioning, the low-density sections 11B and 12B may be simple cavities, as shown in Figure 7. The three-dimensional lattice structure 10 may employ support columns 11 and connecting sections 12 that are hollow on the central side of the high-density sections 11A and 12A, instead of the support columns 11 and connecting sections 12 that have a resin foam interior as exemplified so far. In this embodiment, the support column 11 may be a hollow body (tube) having a cavity in the inner part of the support column 11 in the radial direction Dd that is continuous with the length DL of the support column 11. In this embodiment, the connecting section 12 may be a hollow body (such as a balloon or box) having a cavity on the central side of the high-density section 12A.

[0050] In the three-dimensional lattice structure 10, the cavity in the center of one support column 11 may be continuous in the longitudinal direction DL of the support column 11 and communicate with the cavities of other support columns 11 via the cavities of the connecting portion 12. That is, in one embodiment of the three-dimensional lattice structure 10, a plurality of support columns 11, including a first support column 11 and a second support column 11, are connected to a single connecting portion 12, and the first support column 11, the second support column 11, and the connecting portion 12 connecting them may be hollow bodies, and the cavities inside them may communicate with each other. In the three-dimensional lattice structure 10, the cavities inside the support columns 11 and the connecting portion 12 may communicate throughout the entire three-dimensional lattice structure 10.

[0051] In this case as well, the support column 11 has a high-density section 11A which is a cylindrical body, and the connecting section 12 has a high-density section 12A which is a layered body, resulting in excellent rigidity in each. Furthermore, the three-dimensional lattice structure 10 in this embodiment also exhibits excellent repulsive force against applied loads. In order to make the three-dimensional lattice structure 10 exhibit excellent repulsive force, ribs 11r may be provided on the support column 11 as shown in Figure 8A. The three-dimensional lattice structure 10 may also have ribs 12r on the connecting section 12. The three-dimensional lattice structure 10 may have ribs on both the support column 11 and the connecting section 12.

[0052] Even in a three-dimensional lattice structure 10 with a hollow interior, as shown in Figure 8B, providing ventilation holes 11h in the support columns 11 that connect the internal cavity of the support columns 11 with the external space makes the manifestation of the repulsive force against compressive force more gradual.

[0053] The ribs 11r on the support column 11 may be provided linearly along the length DL of the support column 11, or they may be provided in a spiral pattern around the central axis of the support column 11. Only one rib 11r may be provided on a single support column 11, or multiple ribs may be provided. The ribs 11r may also be provided in a dashed line pattern.

[0054] As shown in Figure 9, assuming a plane P2 passing through the center and the rib 11r, the column 11 exhibits superior rigidity when bent in the direction along the plane P2. On the other hand, when bent in a direction perpendicular to this direction, the column 11 bends relatively more easily than when bent along the plane P2. In other words, by providing the rib 11r, it is possible to make the bending rigidity of the column 11 exhibit anisotropy, and the bending direction of the column 11 can include a high-rigidity direction D1 in which excellent rigidity is exhibited and a low-rigidity direction D2 in which the exhibited rigidity is suppressed compared to the high-rigidity direction D1.

[0055] If the protruding direction (high-rigidity direction D1) of the ribs 11r of the multiple support columns 11 provided in the three-dimensional lattice structure 10 is randomized, the three-dimensional lattice structure 10 exhibits an improved rebound force regardless of the direction in which it is subjected to a load. If the protruding direction of the ribs 11r of the multiple support columns 11 provided in the three-dimensional lattice structure 10 is aligned to a specific direction, the three-dimensional lattice structure 10 also exhibits anisotropy in rigidity, such as rebound force against load. Therefore, by providing ribs 11r, it becomes easier to design the rigidity of the three-dimensional lattice structure 10.

[0056] When the protruding directions of the ribs 11r are aligned to exhibit anisotropy in the rigidity of the three-dimensional lattice structure 10, only some of the support columns 11 may have ribs 11r protruding in a specific direction. When the total number of support columns 11 with ribs 11r is considered to be 100%, the number of support columns 11 with a common protruding direction of ribs 11r may be 10% or more, 20% or more, 30% or more, 40% or more, or 50% or more.

[0057] The protruding direction of the rib 11r is not limited to outward in the radial direction Dd, but may also be inward in the radial direction Dd, as shown in Figure 10. When multiple ribs 11r are provided on a single support column 11, both inward-facing ribs 11r and outward-facing ribs 11r may be provided. Furthermore, the rib 11r may be provided not only on a support column 11 with a hollow interior, but also when the low-density portion 11B is made of resin foam, as shown in Figures 11A and 11B. In such cases as well, the bending direction of the support column 11 can include both a high-rigidity direction D1 and a low-rigidity direction D2.

[0058] As a method for exhibiting anisotropy in bending stiffness, the cross-sectional shape of the support column 11 may be an oval or ellipse, as shown in Figure 12, with the major axis direction being the high-stiffness direction D1 and the minor axis direction being the low-stiffness direction D2. As a method for exhibiting anisotropy in bending stiffness, the thickness of the high-density section 11A may be varied in the circumferential direction Dr, as shown in Figure 13. The thickness of the high-density section 11A may be made thicker in areas parallel to the direction in which the load is applied than in other areas. This makes the direction in which the load is applied the high-stiffness direction D1. As shown in Figure 14, by providing three or more ribs 11r on a single support column 11 and arranging the ribs 11r so that their protruding direction is radial from the center of the support column 11, the bending stiffness of the support column 11 can be improved while suppressing the exhibiting anisotropy in bending stiffness.

[0059] The function of the rib 11r is the same for the rib 12r provided on the connecting part 12. By improving the rigidity of the support columns 11 and connecting parts 12 in this way, even if the support columns 11 are made thinner or the number of support columns 11 connected to a single connecting part 12 is reduced, the three-dimensional lattice structure 10 can exhibit excellent resilience and cushioning properties. In other words, by improving the rigidity of the support columns 11 and connecting parts 12, the three-dimensional lattice structure 10 can be made lighter. Moreover, by making the support columns 11 thinner or reducing the number of support columns 11 and connecting parts 12, collisions between support columns 11, collisions between connecting parts, and collisions between support columns and connecting parts can be suppressed when a large load is applied. Furthermore, even if such a collision occurs, because the inside of the support columns 11 and connecting parts 12 has low rigidity, a sudden and strong resilience force is not generated after the collision. As a result, the cushioning properties of the shoe component made up of the three-dimensional lattice structure 10 are improved.

[0060] The resin composition used in the construction of the support column 11 and the connecting part 12 can be prepared using, for example, olefin resins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-α-olefin copolymer, and polyolefin-based thermoplastic elastomer; styrene resins such as polystyrene, poly-α-methylstyrene, and styrene-based thermoplastic elastomer; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polylactic acid, and polyester-based thermoplastic elastomer; polyamide resins such as polyamide 6, polyamide 66, polyamide 610, and polyamide-based thermoplastic elastomer; polyurethane resins such as polyurethane and polyurethane-based thermoplastic elastomer; polyvinyl chloride; and various types of rubber. The resin composition may also contain various additives such as fillers, softeners, pigments, weathering agents, anti-aging agents, flame retardants, and antibacterial agents.

[0061] The support column 11 has a diameter of, for example, 0.5 mm or more. The diameter of the support column 11 may be 1.0 mm or more, or 1.5 mm or more. The diameter of the support column 11 is, for example, 10.0 mm or less. If the support column 11 is not cylindrical, the diameter of the support column 11 is determined as the diameter of a cylinder having the same apparent volume as the support column 11 and the same length as the support column 11. The distance (center-to-center distance) between one connection part 12 and the other connection part 12 closest to the aforementioned connection part 12 in the three-dimensional lattice structure 10 is, for example, 3 mm or more. The distance between the connection parts 12 may be 4 mm or more, or 5 mm or more. The distance between the connection parts 12 is, for example, 25 mm or less. The distance between the connection parts 12 may be 20 mm or less.

[0062] The three-dimensional lattice structure 10 can be manufactured, for example, using a 3D printer. If the interior of the support columns 11 and connecting parts 12 of the three-dimensional lattice structure 10 is to be made of foam, it may be manufactured by first forming a non-foamed three-dimensional lattice structure using a 3D printer and then foaming the interior of the three-dimensional lattice structure.

[0063] As a method for foaming the inside of the support columns 11 and connecting parts 12, a method may be used in which a thermal decomposition type chemical blowing agent such as azodicarbonamide (ADCA) or bicarbonate is included in the resin composition that forms the central part of the support columns 11 and connecting parts 12. By creating a non-foaming three-dimensional lattice structure containing the chemical blowing agent and heating the three-dimensional lattice structure, the inside of the support columns 11 and connecting parts 12 can be foamed. As a method for foaming the inside of the support columns 11 and connecting parts 12, a method may be employed in which a physical blowing agent such as carbon dioxide, nitrogen, or hydrocarbon is impregnated into the non-foaming three-dimensional lattice structure under pressure, and the non-foaming three-dimensional lattice structure impregnated with the physical blowing agent is heated and depressurized. As a method for foaming the inside, a method using microballoons may be employed.

[0064] As a method for making the surface layers of the support columns 11 and connecting parts 12 high-density parts 11A and 12A, one can employ a method in which at least the surface layer is composed of a reaction-curable (crosslinkable) resin composition, a curing reaction (crosslinking reaction) is caused in the resin composition constituting the surface layer, making the surface layer less susceptible to softening by heat, and then the three-dimensional lattice structure is heated to make the degree of foaming of the surface layer lower than the degree of foaming of the interior.

[0065] The surface layer may be cured (crosslinked) by irradiation with active energy rays such as ultraviolet rays, electron beams, or X-rays, or by thermal curing (thermal crosslinking) through selective heating of the surface layer.

[0066] The resin composition constituting the surface layer does not need to be fully cured (fully crosslinked) before the interior is foamed. It may be partially cured first and then fully cured when the interior is foamed, or a separate post-curing step may be provided after foaming is complete to complete the curing reaction. The three-dimensional lattice structure 10 can be manufactured by various methods other than those described above.

[0067] The disclosures outlined above are merely illustrative examples, and the shoe components described in this disclosure are not limited to these examples. The above disclosures include the following:

[0068] (1) A shoe component in one embodiment is composed of a three-dimensional lattice structure comprising a plurality of support columns and a plurality of connecting parts connecting the support columns, wherein the three-dimensional lattice structure is made of a resin composition, and the three-dimensional lattice structure is provided with a high-density portion in at least one of the support columns and the connecting parts, wherein the high-density portion of the support column has a density higher than the apparent density of the support column and is a cylindrical body constituting the surface layer of the support column, and the high-density portion of the connecting part has a density higher than the apparent density of the connecting part and is a layered body constituting the surface layer of the connecting part. In such an embodiment of the shoe component, since the high-density portion is provided in at least one of the plurality of support columns and the plurality of connecting parts, improved cushioning performance is achieved.

[0069] (2) In the shoe component of (1), the three-dimensional lattice structure may be composed of a repeating unit structure consisting of the plurality of support columns and the connecting parts. In such an embodiment, the sole 2, which is the three-dimensional lattice structure 10, can easily distribute the load when a load is applied by the user's foot. In such an embodiment of the shoe component, the three-dimensional lattice structure 10 can be easily manufactured. In addition, in such an embodiment of the shoe component, the three-dimensional lattice structure 10 can be made homogeneous overall.

[0070] (3) In the shoe component of (1) or (2), when the thickness direction of the three-dimensional lattice structure is the vertical direction, the three-dimensional lattice structure is provided with a connecting portion to which a plurality of the support columns are connected, and the connecting portion is connected to a downward support column which is a support column extending downward from the connecting portion and an upward support column which is a support column extending upward from the connecting portion, and a plurality of the upward support columns are connected, and the plurality of upward support columns may be connected to the connecting portion such that the distance between them increases as they go upward. In such an embodiment, the concentration of load applied to the shoe component when the shoe is used is suppressed, and comfort can be improved.

[0071] (4) In the shoe member of (3), the plurality of upward-facing supports may be connected to the connection portion such that they have the same elevation angle with respect to one of the virtual planes passing through the connection portion to which the plurality of upward-facing supports are connected. In such an embodiment, the load applied to the shoe member can be distributed more effectively.

[0072] (5) In the shoe component of (3) or (4), a plurality of downward-facing supports are connected to the connection portion, and the plurality of downward-facing supports may be connected to the connection portion such that the distance between them increases as they extend downward. In such a configuration, the concentration of load applied to the shoe component when the shoe is used at a specific location is suppressed, and comfort can be improved.

[0073] (6) In the shoe member of (5), the plurality of downward-facing supports may be connected to the connection portion such that they have the same downward angle with respect to one of the virtual planes passing through the connection portion to which the plurality of downward-facing supports are connected. In such an embodiment, the load applied to the shoe member can be distributed more effectively.

[0074] (7) In the shoe member of (6), when the plurality of upward support columns and the plurality of downward support columns are viewed from the direction of the normal to the virtual plane, the plurality of upward support columns and the plurality of downward support columns each extend radially from the connection portion, and each of the plurality of downward support columns may be located between adjacent upward support columns in the circumferential direction when the direction along the circle centered on the connection portion is defined as the circumferential direction. In such an embodiment, when a load is applied to the shoe member, collision between the upward support columns and the downward support columns can be avoided, and good cushioning can be achieved.

[0075] (8) The shoe member of (7) may have the same number of upward support columns as the number of downward support columns, and each of the upward support columns and the downward support columns may be arranged at equal intervals in the circumferential direction. In such an embodiment, the load applied to the shoe member can be distributed more evenly.

[0076] (9) The multiple support columns in the shoe components of (1) to (8) may have different cross-sectional shapes at one point in the longitudinal direction and at another point different from the aforementioned point. In such a configuration, the rigidity design and weight reduction of the shoe components may be facilitated.

[0077] (10) The shoe components of (1) to (9) may have ribs provided in the high-density portion. In such a configuration, the rigidity of the shoe component is improved.

[0078] (11) The shoe components of (1) to (10) are such that the plurality of support columns have the high-density portion, the plurality of support columns are hollow bodies with a cavity radially inward from the high-density portion, and in the plurality of support columns, the cavity may be continuous in the longitudinal direction of the support column. In such a configuration, even if a large load is applied and the support columns collide with each other or with the connection portion, the support columns can be easily compressed and deformed, thus improving the cushioning performance of the shoe component.

[0079] (12) The shoe components of (1) to (11) may have the plurality of connecting parts having the high-density parts, and the plurality of connecting parts may be hollow bodies with cavities on the central side of the high-density parts. In such a configuration, even if a large load is applied and the connecting parts collide with each other or the support column and the connecting parts collide, the connecting parts can be easily compressed and deformed, thereby improving the cushioning performance of the shoe components.

[0080] (13) The shoe components of (1) to (11) are such that the plurality of connecting parts have the high-density parts, and the plurality of connecting parts are hollow bodies having cavities on the central side of the high-density parts, and the cavity of one of the plurality of support columns and the cavity of the other support columns are in communication through the cavity of the connecting part. In such a configuration, the compressive deformability of the support columns and connecting parts is improved by the movement of air inside, and the cushioning performance of the shoe component is improved.

[0081] (14) The support column or the connecting portion of the shoe component of (11) to (13) may be provided with a ventilation hole that connects the external space and the cavity. In such a configuration, the internal air can be discharged to the external space, improving the compressive deformability of the support column and the connecting portion, and improving the cushioning performance of the shoe component.

[0082] (15) At least one of the support column and the connecting portion in the shoe components of (1) to (14) may be made of resin foam in at least a part. In such an embodiment, both the lightness and rigidity of the shoe component can be improved.

[0083] (16) The shoe components of (1) to (10) may have the plurality of support columns having the high-density portion, and the plurality of support columns may be made of resin foam at least radially inward from the high-density portion. In such a configuration, both the lightness and rigidity of the shoe component can be improved.

[0084] (17) The shoe components of (1) to (10) and (16) may have the plurality of connecting parts having the high-density parts, and the plurality of connecting parts may be made of resin foam at least on the central side of the high-density parts. In such a configuration, both the lightness and rigidity of the shoe component can be improved.

[0085] (18) The shoe components of (15) to (17) may have open-cell resin foam. In such a configuration, the cushioning properties of the shoe components can be improved.

[0086] (19) The support column or the connecting portion of the shoe component in (18) may be provided with a ventilation hole that connects the external space with the open air bubble. In such an embodiment, the cushioning performance of the shoe component can be improved.

[0087] (20) In the shoe components of (15) to (17), the resin foam may be a closed-cell foam. In such a configuration, the rigidity of the shoe component can be improved.

[0088] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0089] Three types of three-dimensional lattice structures were fabricated, as shown in Figure 15. Sample 1 is a model in which the entire structure is made of non-foamed resin with a column thickness (diameter) of 2 mm. Sample 2 is a model in which the entire structure is made of non-foamed resin with a column thickness (diameter) of 1 mm. Sample 3 is a variation of Sample 1 in which the central part of the columns and connections is foamed to create a high-density area on the surface.

[0090] Figure 16 shows the results of evaluating the relationship between apparent density and compressive modulus for each sample. As can be seen from these results, simply reducing the diameter may reduce weight, but it results in insufficient rigidity, making it difficult to achieve sufficient cushioning. On the other hand, when a high-density layer is provided on the surface, it is possible to achieve both lightness and cushioning by suppressing the decrease in elastic modulus.

[0091] Next, the degree of foaming was varied, and the relationship between rebound stress and strain in response to the load was evaluated. The results are shown in Figure 17. From this, it was found that the greater the decrease in density, the greater the specific stress and maximum strain. Furthermore, it was found that a delay effect on the abrupt rise of stress occurs with decreasing density.

[0092] From the above, it can be seen that the shoe component disclosed herein is effective in improving cushioning.

[0093] 1: shoe, 2: sole, 3: upper, 10: three-dimensional lattice structure, 11: support, 11A: high-density section, 11B: low-density section, 11r: rib, 11h: ventilation hole, 111: upward support, 112: downward support, 12: connection section, 12A: high-density section, 12B: low-density section, 12r: rib, C: unit structure, CN: vertex, D1: high-rigidity direction, D2: low-rigidity direction, Dd: radial direction, Dr: circumferential direction, Dx: foot length direction, Dy: foot width direction, Dz: height direction, DL: length direction, P1: virtual plane, P2: plane, PL: surface, SD: edge, θ1: elevation angle, θ2: depression angle

Claims

1. A shoe component comprising a three-dimensional lattice structure having a plurality of support columns and a plurality of connecting parts connecting the support columns, wherein the three-dimensional lattice structure is made of a resin composition, and the three-dimensional lattice structure is provided with a high-density portion in at least one of the support columns and the connecting parts, wherein the high-density portion of the support column has a density higher than the apparent density of the support column and is a cylindrical body constituting the surface layer of the support column, and the high-density portion of the connecting part has a density higher than the apparent density of the connecting part and is a layered body constituting the surface layer of the connecting part.

2. The shoe member according to claim 1, wherein the three-dimensional lattice structure is composed of a repeating unit structure consisting of the plurality of support columns and the connecting portion.

3. The shoe member according to claim 1 or 2, wherein, when the thickness direction of the three-dimensional lattice structure is the vertical direction, the three-dimensional lattice structure is provided with a connecting portion to which a plurality of the support columns are connected, and the connecting portion is connected to a downward support column which is a support column extending downward from the connecting portion and an upward support column which is a support column extending upward from the connecting portion, and a plurality of the upward support columns are connected, and the plurality of upward support columns are connected to the connecting portion such that the distance between them increases as they go upward.

4. The shoe member according to claim 3, wherein the plurality of upward-facing support columns are connected to the connection portion such that they have the same elevation angle with respect to one of the virtual planes passing through the connection portion to which the plurality of upward-facing support columns are connected.

5. The shoe member according to claim 3, wherein a plurality of downward-facing support columns are connected to the connection portion, and the plurality of downward-facing support columns are connected to the connection portion such that the distance between them increases as they extend downward.

6. The shoe member according to claim 5, wherein the plurality of downward-facing supports are connected to the connection portion such that they have the same downward angle with respect to one of the virtual planes passing through the connection portion to which the plurality of downward-facing supports are connected.

7. The shoe member according to claim 6, wherein when the plurality of upward-facing supports and the plurality of downward-facing supports are viewed from the direction of the normal to the virtual plane, the plurality of upward-facing supports and the plurality of downward-facing supports each extend radially from the connection portion, and each of the plurality of downward-facing supports is located between adjacent upward-facing supports in the circumferential direction when the direction along the circle centered on the connection portion is defined as the circumferential direction.

8. The shoe member according to claim 7, wherein the number of the plurality of upward support columns is the same as the number of the plurality of downward support columns, and each of the plurality of upward support columns and the plurality of downward support columns is arranged to be equally spaced in the circumferential direction.

9. The shoe member according to claim 1, wherein the plurality of support columns have different cross-sectional shapes at one point in the longitudinal direction and at another point different from the aforementioned point.

10. The shoe component according to claim 1, wherein ribs are provided in the high-density portion.

11. The shoe member according to claim 1, wherein the plurality of support columns have the high-density portion, the plurality of support columns are hollow bodies having a cavity radially inward from the high-density portion, and in the plurality of support columns, the cavity is continuous in the longitudinal direction of the support column.

12. The shoe member according to claim 1, wherein the plurality of connecting portions have the high-density portion, and the plurality of connecting portions are hollow bodies having a cavity on the central side of the high-density portion.

13. The shoe member according to claim 11, wherein the plurality of connecting portions have the high-density portion, the plurality of connecting portions are hollow bodies having a cavity on the central side of the high-density portion, and the cavity of one of the plurality of support columns and the cavity of another support column are in communication through the cavity of the connecting portion.

14. The shoe component according to claim 13, wherein the support column or the connecting portion is provided with a ventilation hole that connects the external space and the cavity.

15. The shoe component according to claim 1, wherein at least one of the support column and the connecting portion is made of resin foam in at least a portion thereof.

16. The shoe component according to claim 1, wherein the plurality of support columns have the high-density portion, and at least the portion radially inward of the plurality of support columns is made of resin foam.

17. The shoe component according to claim 1, wherein the plurality of connecting portions have the high-density portion, and at least the portion of the plurality of connecting portions that is closer to the center than the high-density portion is made of resin foam.

18. The shoe component according to claim 16 or 17, wherein the resin foam has open cells.

19. The shoe component according to claim 18, wherein the support column or the connecting portion is provided with a ventilation hole that connects the external space with the open air bubble.

20. The shoe component according to claim 16 or 17, wherein the resin foam is a closed-cell foam.

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