JP7586860B2 - Soles and shoes - Google Patents

Description

The present invention relates to a shoe sole provided with a shock-absorbing material , and a shoe provided with said sole.

Conventionally, various types of shock absorbing materials are known for absorbing shock, and these various shock absorbing materials are used according to the purpose. For example, in shoes, shock absorbing materials may be provided on the soles to absorb the shock that occurs when landing. The shock absorbing materials provided on the soles are generally made of resin or rubber.

In recent years, shoes have been developed that have lattice or web structured soles to improve cushioning not only in terms of materials but also in terms of structure. For example, U.S. Patent Publication No. 2018/0049514 (Patent Document 1) discloses a shoe with a sole that has a lattice structured sole.

On the other hand, JP2017-527637A (Patent Document 2) describes that it is possible to manufacture three-dimensional objects using three-dimensional additive manufacturing methods, such as polyhedrons with internal cavities and triple periodic minimal surfaces, with thickness added based on their geometric surface structure, and discloses that by constructing the three-dimensional object from an elastic material, it can be used for shoe soles, for example.

US Patent Publication No. 2018/0049514 Special table 2017-527637 publication

The cushioning material, which has a structure in which thickness is added based on the geometric surface structure described above, has the structural characteristic of being easier to achieve high compression rigidity than cushioning materials that include areas with a lattice structure or web structure.

However, when attempting to obtain high compression stiffness in a cushioning material having this structure, the space factor also increases as the wall thickness increases, resulting in a problem of a significant increase in the weight of the cushioning material. In particular, if one wishes to locally increase the compression stiffness of only a portion of the cushioning material and increase the wall thickness of that portion, the increase in weight in that portion becomes significant, making it impossible to avoid an increase in the weight of the cushioning material as a whole, which becomes a major obstacle to weight reduction.

Therefore, the present invention has been made in consideration of the above-mentioned problems, and has an object to provide a sole equipped with a cushioning material that is lightweight and has excellent cushioning performance and can be used for a variety of purposes, and a shoe equipped with such a sole.

The sole according to the first aspect of the present invention comprises a forefoot section supporting the toes and plantar part of the wearer's foot, a midfoot section supporting the arch of the wearer's foot, and a rearfoot section supporting the heel of the wearer's foot, and a ground-contact surface is provided on the underside of the sole. A cushioning material is provided so as to straddle at least the midfoot section and the rearfoot section. The cushioning material includes a three-dimensional structure in which a unit structure is a three-dimensional shape formed by a wall whose outline is defined by a pair of parallel planes or curved surfaces, and the unit structures are regularly and continuously arranged repeatedly in at least one direction. The three-dimensional structure is formed by adding thickness based on a triple periodic minimal curved surface. When the hexahedral space occupied by each of the unit structures is referred to as a unit space, the cushioning material includes a first area which is an area corresponding to the inner part of the midfoot, and which is composed of a plurality of first unit structures, the size of the unit space in a direction parallel to the ground contact surface being a first size, and a second area which is an area corresponding to the outer part of the rear foot and the rear part of the outer side of the midfoot, and which is composed of a plurality of second unit structures, the size of the unit space in a direction parallel to the ground contact surface being a second size larger than the first size.
The sole according to the second aspect of the present invention comprises a forefoot section supporting the toes and plantar part of the wearer's foot, a midfoot section supporting the arch of the wearer's foot, and a rearfoot section supporting the heel of the wearer's foot, and a ground-contact surface is provided on the underside of the sole. A cushioning material is provided so as to straddle at least the midfoot section and the rearfoot section. The cushioning material includes a three-dimensional structure in which a unit structure is a three-dimensional shape formed by a wall whose outer shape is defined by a pair of parallel planes or curved surfaces, and the unit structures are regularly and continuously arranged in at least one direction. The three-dimensional structure is formed by adding thickness based on a plurality of planes arranged to intersect with each other so as to have a cavity inside. When the hexahedral space occupied by each of the unit structures is referred to as a unit space, the cushioning material includes a first area which is an area corresponding to the inner part of the midfoot, and which is composed of a plurality of first unit structures, the size of the unit space in a direction parallel to the ground contact surface being a first size, and a second area which is an area corresponding to the outer part of the rear foot and the rear part of the outer side of the midfoot, and which is composed of a plurality of second unit structures, the size of the unit space in a direction parallel to the ground contact surface being a second size larger than the first size.

The shoe according to the present invention comprises a sole according to the present invention described above and an upper provided above the sole.

According to the present invention, it is possible to provide a shoe sole equipped with a cushioning material that is lightweight and has excellent cushioning performance and that can be used for various purposes, and a shoe equipped with said sole.

FIG. 2 is a partially cutaway perspective view of the cushioning material according to the first embodiment. FIG. 2 is a front view of the cushioning material shown in FIG. FIG. 2 is a cross-sectional view of the cushioning material shown in FIG. 13 is a graph showing the results of simulating the cushioning performance of the cushioning materials according to Verification Examples 1 and 2. FIG. 13 is a partially cutaway perspective view showing the basic configuration of another example of a geometric surface structure based on a curved surface. FIG. 13 is a partially cutaway perspective view showing the basic configuration of yet another example of a geometric surface structure based on a curved surface. FIG. 11 is a partially cutaway perspective view of a cushioning material according to a second embodiment. 13 is a graph showing the results of simulating the cushioning performance of the cushioning materials according to Verification Examples 3 and 4. FIG. 13 is a partially cutaway perspective view showing the basic configuration of another example of a geometric surface structure based on a plane. FIG. 13 is a partially cutaway perspective view showing the basic configuration of yet another example of a geometric surface structure based on a plane. 11 is a perspective view of a shoe sole and a shoe having the same according to a third embodiment. FIG. FIG. 12 is a side view of the sole shown in FIG. 11 . FIG. 12 is a schematic plan view showing the configuration of the shoe sole shown in FIG. 11 . FIG. 12 is a cross-sectional view of the shoe sole shown in FIG. 12 is a schematic diagram showing an example of the arrangement of unit structures of the cushioning material in the sole shown in FIG. 11 . FIG. FIG. 13 is a schematic plan view showing the configuration of a shoe sole according to a fourth embodiment. FIG. 17 is a cross-sectional view of the sole shown in FIG. 16. FIG. 11 is a cross-sectional view of a shoe sole according to a first modified example. FIG. 11 is a cross-sectional view of a shoe sole according to a second modified example. FIG. 11 is a cross-sectional view of a shoe sole according to a third modified example. FIG. 13 is a schematic cross-sectional view showing the configuration of a shoe sole according to a fourth modified example. FIG. 13 is a schematic cross-sectional view showing the configuration of a shoe sole according to a fifth modified example. FIG. 13 is a schematic plan view showing the configuration of a shoe sole according to embodiment 5. FIG. 24 is a cross-sectional view of the sole shown in FIG. 23. FIG. 13 is a cross-sectional view of a shoe sole according to a seventh modified example. FIG. 13 is a cross-sectional view of a shoe sole according to an eighth modified example. FIG. 13 is a schematic plan view showing the configuration of a shoe sole according to a sixth embodiment. FIG. 28 is a schematic cross-sectional view showing the configuration of the shoe sole shown in FIG. 27. FIG. 28 is a schematic cross-sectional view showing the configuration of the shoe sole shown in FIG. 27. FIG. 13 is a schematic plan view showing the configuration of a shoe sole according to embodiment 7. FIG. 31 is a schematic cross-sectional view showing the configuration of the shoe sole shown in FIG. 30.

The following describes in detail the embodiments of the present invention with reference to the drawings. In the embodiments described below, the same or common parts are given the same reference numerals in the drawings, and their description will not be repeated.

(Embodiment 1)
Fig. 1 is a partially cutaway perspective view of a cushioning material according to embodiment 1. Fig. 2 is a front view of the cushioning material as viewed from the direction of arrow II shown in Fig. 1. Fig. 3 is a cross-sectional view of the cushioning material taken along line III-III shown in Fig. 1. Hereinafter, cushioning material 1A according to this embodiment will be described with reference to Figs. 1 to 3.

As shown in Figures 1 to 3, the cushioning material 1A includes a three-dimensional structure S having a plurality of unit structures U (see Figure 1 in particular). Each of the unit structures U has a three-dimensional shape formed by walls 10 whose outer shape is defined by a pair of parallel curved surfaces.

Here, in FIG. 1, for ease of understanding, the reference symbol U is not strictly attached to the unit structure, but to the unit space of a hexahedron shape (particularly a rectangular parallelepiped shape in this embodiment), which is the space occupied by the unit structure.

The multiple unit structures U are regularly and continuously arranged in a repeated manner along each of the width direction (X direction shown in the figure), depth direction (Y direction shown in the figure), and height direction (Z direction shown in the figure). Figures 1 to 3 show four unit structures U adjacent to each other in the width direction and depth direction, and three unit structures U adjacent to each other in the height direction.

In this embodiment, the cushioning material 1A is described as having a large number of unit structures U arranged in each of the width, depth, and height directions, but the number of repetitions of the unit structures U in the width, depth, and height directions is not particularly limited, and it is sufficient that two or more unit structures U are arranged in at least one of these three directions.

The cushioning material 1A in this embodiment is designed to provide a cushioning function in the height direction (the Z direction shown in the figure). Therefore, the axial direction in which the cushioning material 1A provides a cushioning function when subjected to a load coincides with the height direction described above.

As described above, each of the multiple unit structures U has a three-dimensional shape formed by the walls 10. Therefore, by continuously connecting these multiple unit structures U to each other, the three-dimensional structure S is also composed of an assembly of these walls 10.

The three-dimensional structure S included in the cushioning material 1A has a structure in which thickness is added based on a geometric surface structure. In the cushioning material 1A according to this embodiment, the surface structure is a Schwarzian P structure, which is a type of mathematically defined triply periodic minimal surface. Note that a minimal surface is defined as a surface with the smallest area among those having a given closed curve as its boundary.

As shown in FIG. 3, the three-dimensional structure S, which is based on the Schwarz P structure and has a thickness added to it, has a meandering portion 11, which is a portion that has a meandering cross-sectional shape when cut along a specific plane. In this embodiment, the specific plane is a plane that is perpendicular to the paper surface and parallel to line III-III in FIG. 1.

Due to the structure of the three-dimensional structure S, there are three types of serpentine portions 11: those that extend along the width direction, those that extend along the depth direction, and those that extend along the height direction. However, here we focus on the serpentine portions 11 that extend along the height direction (i.e., the Z direction) that appear in the cross section shown in Figure 3.

The meandering section 11 extending in the height direction has a plurality of direction change points 12 located along the height direction, and each of the direction change points 12 has an inside corner 13 and an outside corner 14. Of these, the inside corner 13 is a portion that appears to have a concave shape on the surface of the wall 10 in the above cross-sectional shape, and the outside corner 14 is a portion that appears to have a convex shape on the surface of the wall 10 in the above cross-sectional shape. Here, the meandering section 11 extending in the height direction has a distance between adjacent meandering sections that differs depending on the position in the height direction, and the above-mentioned distance periodically increases and decreases as it moves along the height direction.

As shown in Figures 1 to 3, the cushioning material 1A according to this embodiment includes two types of unit structures UA and UB with different external shapes as unit structures U. The unit space occupied by the unit structure UA is a regular hexahedron, and the unit space occupied by the unit structure UB is a hexahedron that is elongated in the height direction.

The unit structure UA is configured so that, of the three mutually orthogonal sides that define the unit space, the side extending in the height direction (i.e., Z direction) is the first side, the side extending in the width direction (i.e., X direction) is the second side, and the side extending in the depth direction (i.e., Y direction) is the third side, and all of these first to third sides are the same length. That is, referring to FIG. 1, if the width dimension of the unit structure UA is Lx1, the depth dimension of the unit structure UA is Ly1, and the height dimension of the unit structure UA is Lz1, the relationship Lx1=Ly1=Lz1 is satisfied. In FIG. 1, the unit structures UA are arranged in two layers (layers in the range represented by reference symbol LY1) on the upper side of the three-dimensional structure S.

The unit structure UB is configured such that, of the three mutually orthogonal sides that define the unit space, the side extending in the height direction (i.e., Z direction) is the first side, the side extending in the width direction (i.e., X direction) is the second side, and the side extending in the depth direction (i.e., Y direction) is the third side, the second side and the third side are the same length, and the first side is twice the length of the second side and the third side. That is, referring to FIG. 1, when the width dimension of the unit structure UB is Lx2, the depth dimension of the unit structure UB is Ly2, and the height dimension of the unit structure UB is Lz2, the relationship Lx2=Ly2=Lz2/2 is satisfied. In FIG. 1, the unit structure UB is arranged in one layer (layer in the range represented by reference symbol LY2) on the lower side of the three-dimensional structure S.

As a result, in the cushioning material 1A of this embodiment, the unit structures U that have different outer dimensions of the unit space (i.e., the two types of unit structures UA and UB with different outer shapes as described above) are positioned in the axial direction (i.e., height direction) in which the cushioning material 1A exerts its cushioning function when subjected to a load.

In this way, the three-dimensional structure S includes unit structures U each having a different outer dimension of the unit space, making it possible to produce a lightweight cushioning material with excellent cushioning performance, the details of which will be described later.

In addition, among the above-mentioned dimensions of the unit structure U, if the height dimension, which is the axial direction in which the cushioning function is intended to be exerted, is L1, and the longer of the remaining width and depth dimensions is L2, then if at least one of the above-mentioned unit structures UA, UB satisfies the condition 1.1≦L1/L2≦4.0, high compression stiffness can be obtained in the part that satisfies this condition. On the other hand, if at least one of the above-mentioned unit structures UA, UB satisfies the condition 0.1≦L1/L2≦0.9, high deformability can be obtained by reducing the compression stiffness in the part that satisfies this condition. However, the above-mentioned unit structures UA, UB do not necessarily need to satisfy this condition, and it is optional whether or not they satisfy it.

The manufacturing method of the cushioning material 1A is not particularly limited, but the cushioning material 1A can be manufactured, for example, by modeling using a three-dimensional additive manufacturing device.

The material for the buffer material 1A can basically be any material that has elasticity, but it is preferably a resin material or a rubber material. More specifically, if the buffer material 1A is made of resin, it can be a thermoplastic resin such as ethylene-vinyl acetate copolymer (EVA), or a thermosetting resin such as polyurethane (PU). On the other hand, if the buffer material 1A is made of rubber, it can be butadiene rubber, for example.

The buffer material 1A may also be composed of a polymer composition. In this case, examples of the polymer contained in the polymer composition include olefin-based polymers such as olefin-based elastomers and olefin-based resins. Examples of olefin-based polymers include polyethylene (for example, linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), etc.), polypropylene, ethylene-propylene copolymers, propylene-1-hexene copolymers, propylene-4-methyl-1-pentene copolymers, propylene-1-butene copolymers, ethylene-1-hexene copolymers, ethylene-4-methyl-pentene copolymers, ethylene-1-butene copolymers, 1-butene-1-hexene copolymers, 1-butene-4-methyl-pentene, ethylene-methacrylic acid copolymers, ethylene-methyl methacrylate copolymers, ethylene-methacryloyl ester ... Examples of polyolefins include ethyl acrylate copolymer, ethylene-butyl methacrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, propylene-methacrylic acid copolymer, propylene-methyl methacrylate copolymer, propylene-ethyl methacrylate copolymer, propylene-butyl methacrylate copolymer, propylene-methyl acrylate copolymer, propylene-ethyl acrylate copolymer, propylene-butyl acrylate copolymer, ethylene-vinyl acetate copolymer (EVA), and propylene-vinyl acetate copolymer.

The polymer may be an amide-based polymer such as an amide-based elastomer or an amide-based resin. Examples of amide-based polymers include polyamide 6, polyamide 11, polyamide 12, polyamide 66, and polyamide 610.

The polymer may be an ester-based polymer, such as an ester-based elastomer or an ester-based resin. Examples of ester-based polymers include polyethylene terephthalate and polybutylene terephthalate.

The polymer may be a urethane-based polymer, such as a urethane-based elastomer or a urethane-based resin. Examples of urethane-based polymers include polyester-based polyurethanes and polyether-based polyurethanes.

The polymer may be a styrene-based polymer such as a styrene-based elastomer or a styrene-based resin. Examples of styrene-based elastomers include styrene-ethylene-butylene copolymer (SEB), styrene-butadiene-styrene copolymer (SBS), hydrogenated SBS (styrene-ethylene-butylene-styrene copolymer (SEBS)), styrene-isoprene-styrene copolymer (SIS), hydrogenated SIS (styrene-ethylene-propylene-styrene copolymer (SEPS)), styrene-isobutylene-styrene copolymer (SIBS), styrene-butadiene-styrene-butadiene (SBSB), styrene-butadiene-styrene-butadiene-styrene (SBSBS), etc. Examples of styrene-based resins include polystyrene, acrylonitrile styrene resin (AS), acrylonitrile butadiene styrene resin (ABS), etc.

The polymer may be, for example, an acrylic polymer such as polymethyl methacrylate, a urethane acrylic polymer, a polyester acrylic polymer, a polyether acrylic polymer, a polycarbonate acrylic polymer, an epoxy acrylic polymer, a conjugated diene polymer acrylic polymer and its hydrogenated product, a urethane methacrylic polymer, a polyester methacrylic polymer, a polyether methacrylic polymer, a polycarbonate methacrylic polymer, an epoxy methacrylic polymer, a conjugated diene polymer methacrylic polymer and its hydrogenated product, a polyvinyl chloride resin, a silicone elastomer, butadiene rubber (BR), isoprene rubber (IR), chloroprene (CR), natural rubber (NR), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), butyl rubber (IIR), etc.

As described above, the cushioning material 1A according to this embodiment is lightweight and has excellent cushioning performance. This is largely due to the structural features (shape features) of the cushioning material 1A. This point will be explained in detail below based on the results of the first verification test conducted by the inventor.

Figure 4 is a graph showing the results of simulating the cushioning performance of the cushioning materials in verification examples 1 and 2.

In the first verification test, models of the cushioning materials according to verification examples 1 and 2 were specifically designed, and a case was assumed in which an external force was applied to these models in a specific direction, and the behavior in that case was individually analyzed by simulation. More specifically, so-called stress-strain curves were obtained for each of these models.

Here, the cushioning material in verification example 1 has a three-dimensional structure S entirely composed of the unit structures UA described above. More specifically, the cushioning material in verification example 1 has a unit structure UA with a width dimension Lx1, depth dimension Ly1, and height dimension Lz1 of 10 mm, respectively, and the aspect ratio L1/L2 represented by the above-mentioned L1 and L2 is 1.0. The thickness of the wall 10 is 2.36 mm, and the space factor V in this case is approximately 50%.

On the other hand, the cushioning material according to verification example 2 has a three-dimensional structure S entirely composed of the unit structure UB described above. More specifically, the cushioning material according to verification example 2 has a unit structure UB with a width dimension Lx2 and a depth dimension Ly2 of 5 mm each, and a height dimension Lz2 of 10 mm, and the aspect ratio L1/L2 represented by the above-mentioned L1 and L2 is 2.0. The thickness of the wall 10 is 1.36 mm, and the space factor V in this case is approximately 50%.

The direction of the external force applied to the cushioning materials in both verification examples 1 and 2 was the height direction, which is the axial direction described above. The material of the cushioning materials in both verification examples 1 and 2 was assumed to be a urethane-based acrylic polymer with an elastic modulus of 0.5 MPa.

Normally, when increasing the compressive rigidity, it is considered to increase the thickness of the wall 10 of the unit structure U. However, when the thickness of the wall 10 is increased, the space factor V also increases accordingly, and the thicker the wall 10, the higher the space factor V becomes, resulting in a heavier cushioning material. In other words, there is a so-called trade-off between ensuring compressive rigidity and reducing weight.

However, as shown in FIG. 4, the cushioning material according to Verification Example 2 has a higher compressive rigidity than the cushioning material according to Verification Example 1, even though the cushioning material according to Verification Example 2 has the same space factor as the cushioning material according to Verification Example 1. This is thought to be because the wall 10 acts more like a screen in the cushioning material according to Verification Example 2, as a result of shortening the width direction length of the unit structure.

Therefore, based on the results of the first verification test described above, it can be seen that by configuring the cushioning material 1A as described above, which includes unit structures with different external dimensions, it is possible to significantly reduce the increase in weight of the cushioning material, compared to a case in which the thickness of the wall 10 in that portion is increased overall in order to obtain locally high compression stiffness.

Therefore, by using the cushioning material 1A according to the present embodiment described above, it is possible to produce a lightweight cushioning material with excellent cushioning performance that can be used for a variety of purposes.

In the present embodiment, as described above, the unit structures U each having a different outer dimension of the unit space are arranged in the axial direction in which the buffer material 1A exerts its buffer function when loaded, but they may be arranged in a direction intersecting the axial direction in which the buffer material exerts its buffer function when loaded. Even when configured in this way, it is possible to obtain a lightweight buffer material with excellent buffer performance that can be used for various purposes.

Here, three-dimensional shapes formed by walls whose outlines are defined by a pair of parallel curved surfaces include those based on the Schwartz P structure described above with added thickness, as well as those based on the gyroid structure with added thickness and those based on the Schwartz D structure with added thickness. These gyroid and Schwartz D structures, like the Schwartz P structure described above, are also types of mathematically defined triply periodic minimal surfaces.

Figure 5 is a partially cutaway perspective view showing the basic configuration of a gyroid structure. In Figure 5, four unit structures U adjacent in the width direction and depth direction, and two unit structures U adjacent in the height direction are shown. Note that the unit structure U shown in Figure 5 is configured such that the unit space occupied by the unit structure U is an elongated hexahedron in the height direction.

Figure 6 is a partially cutaway perspective view showing the basic configuration of the Schwarz D structure. In Figure 6, eight unit structures U adjacent in the width direction and depth direction, and four unit structures U adjacent in the height direction are shown. Note that the unit structure U shown in Figure 6 is configured such that the unit space occupied by the unit structure U is an elongated hexahedron in the height direction.

Although specific illustrations are omitted here, in a cushioning material that includes a three-dimensional structure S as a buffer region, which is based on a gyroid structure or a Schwartz D structure and has been given a thickness, as described above, the three-dimensional structure S may be configured to include unit structures U with different external dimensions of the unit space. Even when configured in this way, it can be a lightweight cushioning material with excellent buffering performance that can be used for a variety of purposes.

(Embodiment 2)
Fig. 7 is a partially cutaway perspective view of a cushioning material according to embodiment 2. Hereinafter, a cushioning material 1B according to the present embodiment will be described with reference to Fig. 7.

As shown in FIG. 7, the cushioning material 1B includes a three-dimensional structure S having a plurality of unit structures U. Each of the unit structures U has a three-dimensional shape formed by walls 10 whose outline is defined by a pair of parallel planes.

Here, in FIG. 7, for ease of understanding, the reference symbol U is not strictly attached to the unit structure, but to the unit space of a hexahedron shape (particularly a rectangular parallelepiped shape in this embodiment), which is the space occupied by the unit structure.

The multiple unit structures U are regularly and continuously arranged in a repeated manner along each of the width direction (X direction shown in the figure), depth direction (Y direction shown in the figure), and height direction (Z direction shown in the figure). In FIG. 7, four unit structures U adjacent to each other in the width direction and depth direction, and three unit structures U adjacent to each other in the height direction are shown.

As described above, each of the multiple unit structures U has a three-dimensional shape formed by the walls 10. Therefore, by continuously connecting these multiple unit structures U to each other, the three-dimensional structure S is also composed of an assembly of these walls 10.

Here, the three-dimensional structure S included in the cushioning material 1B has a structure in which thickness is added based on a geometric plane structure. In the cushioning material 1B according to this embodiment, the plane structure is an octet structure made up of multiple planes arranged to intersect with each other so as to have a cavity inside.

As shown in FIG. 7, the cushioning material 1B according to this embodiment includes two types of unit structures UA and UB with different outer shapes as unit structures U. The unit space occupied by the unit structure UA is a regular hexahedron, and the unit space occupied by the unit structure UB is a hexahedron that is elongated in the height direction.

Here, the unit structure UA is configured so that the first to third sides defining the unit space are all the same length, as in the case of the above-mentioned embodiment 1. In other words, if the width dimension of the unit structure UA is Lx1, the depth dimension of the unit structure UA is Ly1, and the height dimension of the unit structure UA is Lz1, then the relationship Lx1 = Ly1 = Lz1 is satisfied. In FIG. 7, the unit structures UA are arranged in two layers (layers in the range indicated by reference symbol LY1) on the upper side of the three-dimensional structure S.

On the other hand, the unit structure UB is configured in the same way as in the first embodiment described above, so that of the first to third sides that define the unit space, the second and third sides are the same length, and the first side is twice the length of the second and third sides. In other words, if the width dimension of the unit structure UB is Lx2, the depth dimension of the unit structure UB is Ly2, and the height dimension of the unit structure UB is Lz2, the relationship Lx2 = Ly2 = Lz2/2 is satisfied. In FIG. 7, the unit structure UB is arranged in one layer (the layer in the range represented by reference symbol LY2) on the lower side of the three-dimensional structure S.

As a result, even in the cushioning material 1B of this embodiment, unit structures U with different outer dimensions of the unit space (i.e., the two types of unit structures UA and UB with different outer shapes described above) are positioned in the axial direction (i.e., height direction) in which the cushioning material 1B exerts its cushioning function when subjected to a load.

In addition, among the above-mentioned dimensions of the unit structure U, if the height dimension, which is the axial direction in which the cushioning function is intended to be exerted, is L1, and the longer of the remaining width and depth dimensions is L2, then if at least one of the above-mentioned unit structures UA, UB satisfies the condition 1.1≦L1/L2≦4.0, high compression stiffness can be obtained in the part that satisfies this condition. On the other hand, if at least one of the above-mentioned unit structures UA, UB satisfies the condition 0.1≦L1/L2≦0.9, high deformability can be obtained by reducing the compression stiffness in the part that satisfies this condition. However, the above-mentioned unit structures UA, UB do not necessarily need to satisfy this condition, and it is optional whether or not they satisfy it.

Figure 8 is a graph showing the results of simulating the cushioning performance of the cushioning materials according to verification examples 3 and 4. Below, we will refer to this Figure 8 to explain the second verification test that verified the effects obtained when using the cushioning material 1B according to this embodiment.

In the second verification test, models of the cushioning materials according to verification examples 3 and 4 were specifically designed, and a case was assumed in which an external force was applied to these models in a specific direction, and the behavior in that case was individually analyzed by simulation. More specifically, so-called stress-strain curves were obtained for each of these models.

Here, the cushioning material according to verification example 3 has a three-dimensional structure S entirely composed of the unit structures UA described above. More specifically, the cushioning material according to verification example 3 has a unit structure UA with a width dimension Lx1, depth dimension Ly1, and height dimension Lz1 of 20 mm, respectively, and the aspect ratio L1/L2 represented by the above-mentioned L1 and L2 is 1.0. The thickness of the wall 10 is 1.6 mm, and the space factor V in this case is approximately 50%.

On the other hand, the cushioning material according to verification example 4 has a three-dimensional structure S entirely composed of the unit structure UB described above. More specifically, the cushioning material according to verification example 4 has a unit structure UB with a width dimension Lx2 and a depth dimension Ly2 of 10 mm each, and a height dimension Lz2 of 20 mm, and the aspect ratio L1/L2 represented by the above-mentioned L1 and L2 is 2.0. The thickness of the wall 10 is 0.8 mm, and the space factor V in this case is approximately 50%.

The direction of the external force applied to the cushioning materials in Test Examples 3 and 4 was the height direction, which is the axial direction described above. The material of the cushioning materials in Test Examples 3 and 4 was assumed to be a urethane-based acrylic polymer with an elastic modulus of 9 MPa.

As shown in Figure 8, the cushioning material of Verification Example 4 has a higher compression stiffness than the cushioning material of Verification Example 3, even though the cushioning material of Verification Example 4 has the same space factor as the cushioning material of Verification Example 3. This is thought to be because the wall 10 acts more like a screen due to the shortening of the width direction length of the unit structure in the cushioning material of Verification Example 4, thereby increasing the compression stiffness.

Therefore, based on the results of the second verification test described above, it can be understood that by configuring the cushioning material 1B as described above, which includes unit structures with different external dimensions, it is possible to significantly reduce the increase in weight of the cushioning material, compared to a case in which the thickness of the wall 10 in that portion is increased overall in order to obtain locally high compression stiffness.

Therefore, by using the cushioning material 1B according to the present embodiment described above, it is possible to produce a lightweight cushioning material with excellent cushioning performance that can be used for a variety of purposes.

Here, three-dimensional shapes formed by walls whose outlines are defined by a pair of parallel planes include those based on the octet structure described above with added thickness, as well as those based on a cubic structure with added thickness and those based on a cubic octet structure with added thickness. Like the octet structure described above, these cubic and cubic octet structures are also made up of multiple planes arranged to intersect with each other so that they have a cavity inside.

Figure 9 is a partially cutaway perspective view showing the basic configuration of a cubic structure. In Figure 9, only two unit structures U adjacent to each other in the width direction and depth direction are shown. Note that the unit structure U shown in Figure 9 is configured such that the unit space occupied by the unit structure U is an elongated hexahedron in the height direction.

Figure 10 is a partially cutaway perspective view showing the basic configuration of a cubic octet structure. In this figure, only two unit structures U adjacent to each other in the width direction and depth direction are shown. Note that the unit structure U shown in Figure 10 is configured such that the unit space occupied by the unit structure U is an elongated hexahedron in the height direction.

Although specific illustrations are omitted here, in a cushioning material that includes a three-dimensional structure S as a buffer region that is based on these cubic structures or cubic octet structures and has been given a thickness, as described above, the three-dimensional structure S may be configured to include unit structures U with different outer dimensions of the unit space. Even when configured in this way, it can be a lightweight cushioning material with excellent cushioning performance that can be used for a variety of purposes.

(Embodiment 3)
FIG. 11 is a perspective view of a sole according to the third embodiment and a shoe having the sole. FIG. 12 is a side view of the sole shown in FIG. 11. FIG. 13 is a schematic diagram showing the configuration of the sole shown in FIG. 11 when viewed from the direction of the arrow XIII shown in FIG. 12. FIG. 14 is a cross-sectional view of the sole taken along the line XIV-XIV shown in FIG. 13. FIG. 15 is a schematic diagram showing an example of the arrangement of unit structures of the buffer material in the sole shown in FIG. 11. Here, FIG. 15(A) is a schematic cross-sectional view of the sole taken along the line XVA-XVA shown in FIG. 12. Hereinafter, a sole 110A according to the present embodiment and a shoe 100 having the sole will be described with reference to these FIGS. 11 to 15. The sole 110A according to the present embodiment is provided with the buffer material 1A according to the first embodiment described above.

As shown in FIG. 11, the shoe 100 comprises a sole 110A and an upper 120. The sole 110A is a member that covers the bottom of the foot and has a generally flat shape. The upper 120 has a shape that covers at least the entire part of the instep side of the foot into which it is inserted, and is located above the sole 110A.

The upper 120 has an upper body 121, a shoe tongue 122, and shoe laces 123. Of these, the shoe tongue 122 and the shoe laces 123 are both fixed or attached to the upper body 121.

The upper part of the upper body 121 has an upper opening that exposes the upper part of the ankle and part of the instep. On the other hand, the lower part of the upper body 121 has a lower opening that is covered by the sole 110A, for example, and as another example, the bottom is formed by sewn the lower end of the upper body 121.

The shoe tongue 122 is fixed to the upper body 121 by sewing, welding, or bonding, or a combination of these, so as to cover the upper opening of the upper body 121 that exposes part of the instep. The upper body 121 and the shoe tongue 122 are made of, for example, woven or knitted fabric, nonwoven fabric, synthetic leather, resin, etc., and for shoes that require particular breathability and lightness, double raschel warp knit fabric woven with polyester yarn is used.

The shoelace 123 is made of a string-like member that draws together the periphery of an upper opening in the upper body 121, which exposes part of the instep, in the foot width direction, and is inserted through a number of holes provided on the periphery of the upper opening. By tightening the shoelace 123 when the foot is inserted into the upper body 121, the upper body 121 can be made to fit closely to the foot.

As shown in Figures 11 to 14, the sole 110A has a midsole 111, an outsole 112, and a cushioning material 1A. The midsole 111 is located on the top of the sole 110A and is joined to the upper 120. The outsole 112 has a ground contact surface 112a (see Figures 12 and 14) on its underside and is located below the sole 110A. The cushioning material 1A is interposed at a predetermined position between the midsole 111 and the outsole 112.

It is preferable that the midsole 111 has a suitable strength while also having excellent cushioning properties. From this viewpoint, the midsole 111 can be made of, for example, a foam material made of resin or rubber, and particularly preferably, a foam material made of a thermoplastic resin such as ethylene-vinyl acetate copolymer (EVA), a thermosetting resin such as polyurethane (PU), or butadiene rubber.

It is preferable that the outsole 112 has excellent abrasion resistance and grip, and from this viewpoint, the outsole 112 can be made of, for example, rubber. Note that a tread pattern may be provided on the ground surface 112a, which is the lower surface of the outsole 112, from the viewpoint of enhancing the grip described above.

12 and 13, the sole 110A is divided along the longitudinal direction (left-right direction in FIG. 12, up-down direction in FIG. 13) which is the long axis direction in a plan view into a forefoot portion R1 which supports the toes and the plantar portion of the foot, a midfoot portion R2 which supports the arch of the foot, and a rearfoot portion R3 which supports the heel of the foot. Also, as shown in FIG. 13 and 14, the sole 110A is divided along the foot width direction which is the direction intersecting with the long axis direction in a plan view into an inner foot portion (the portion on the S1 side shown in the figure) which is the midline side (i.e. the side closer to the midline) in the anatomical orthogonal position of the foot, and an outer foot portion (the portion on the S2 side shown in the figure) which is the opposite side of the midline side in the anatomical orthogonal position of the foot (i.e. the side farther from the midline).

As shown in FIG. 13, the inner side (S1 side) of the forefoot part R1 of the sole 110A includes a part Q1 that supports the big toe. The outer side (S2 side) of the forefoot part R1 of the sole 110A includes a part Q2 that supports the little toe. Meanwhile, the rear foot part R3, which straddles the inner side (S1 side) and outer side (S2 side) of the sole 110A, includes a part Q3 that supports the calcaneus.

Here, in the shoe 100 according to this embodiment, a cutout portion of a predetermined shape is provided in the midsole 111, and the cushioning material 1A is accommodated in the cutout portion, so that the cushioning material 1A is fixed in a state where it is sandwiched between the midsole 111 and the outsole 112 in the thickness direction of the sole 110A.

12 to 14, the midsole 111 has a cutout portion that is approximately U-shaped in plan view, straddling the midfoot portion R2 and the rearfoot portion R3 along the periphery of the sole 110A, and the cushioning material 1A, which is formed to be approximately U-shaped in plan view as a whole, is arranged to fill the cutout portion. More specifically, the cushioning material 1A is arranged along the inner edge of the midfoot portion R2, the inner edge of the rearfoot portion R3, the rear edge of the rearfoot portion R3, the outer edge of the rearfoot portion R3, and the outer edge of the midfoot portion R2. In FIG. 13, the arrangement area of the cushioning material 1A when the sole 110A is viewed in plan is light-colored to make it easier to understand. That is, the cushioning material 1A has a cushioning area not only on the edge of the sole 110A described above, but also in a part of its inner area.

As explained in the first embodiment above, the material of the buffer material 1A is not particularly limited, but may be, for example, a resin material or a rubber material, and particularly preferably, a thermoplastic resin such as ethylene-vinyl acetate copolymer (EVA), a thermosetting resin such as polyurethane (PU), butadiene rubber, etc. Also, it may be a polymer composition such as an olefin-based polymer, an amide-based polymer, an ester-based polymer, a urethane-based polymer, a styrene-based polymer, or an acrylic-based polymer.

The thickness of the walls 10 constituting the three-dimensional structure S of the cushioning material 1A is not particularly limited, but is preferably 0.1 mm or more and 10 mm or less, and more preferably 1 mm or more and 5 mm or less.

As shown in Figures 12 and 14, the cushioning material 1A is arranged so that its height direction (Z direction in the figures), which is the axial direction mentioned above, is perpendicular to the ground contact surface 112a of the sole 110A. By configuring it in this way, the load applied to the sole 110A from the sole and the ground when landing is absorbed by the cushioning material 1A deforming with a large amount of deformation, reducing the load applied to the sole from the sole 110A, and achieving high cushioning performance.

In this embodiment, the cushioning material 1A is arranged to surround the portion Q3 of the sole 110A that supports the calcaneus of the foot, so that particularly high cushioning performance is obtained in this portion.

As shown in FIG. 14, the cushioning material 1A is interposed between the midsole 111 and the outsole 112 so that a layer LY1 formed by arranging a plurality of unit structures UA (see FIG. 1, etc.) is disposed on the upper side of the sole 110A, and a layer LY2 formed by arranging a plurality of unit structures UB (see FIG. 1, etc.) is disposed on the lower side of the sole 110A.

Here, layer LY1, which is formed by arranging multiple unit structures UA, has a relatively low compressive stiffness, and layer LY2, which is formed by arranging multiple unit structures UB, has a relatively high compressive stiffness. Therefore, layer LY1 is a relatively soft part, and layer LY2 is a relatively hard part.

Therefore, by adopting this configuration, layer LY2, which is a relatively hard portion, is provided in sole 110A, and the foot can be stably supported, particularly in midfoot portion R2 and rearfoot portion R3, when landing, and layer LY1, which is a relatively soft portion, is located above layer LY2, which significantly improves the feel on the foot.

Therefore, by making the sole 110A according to this embodiment and the shoe 100 equipped with the sole, it is possible to obtain a sole that is lightweight and has excellent cushioning properties, and a shoe equipped with the sole.

The cushioning material 1A may be formed into a generally U-shaped shape in plan view as described above by combining and bonding a number of independent members together, but more preferably, the entire material is formed into a single member to form the generally U-shaped shape in plan view as described above. In particular, when adopting the latter configuration, it is important to determine how to layout the cushioning material 1A, which includes a number of unit structures U each having a rectangular parallelepiped shape, relative to the non-rectangular cutout portion while eliminating unnecessary bias in the cushioning performance for each portion.

Below, with reference to Figures 15(A) to 15(E), we will explain a specific design technique that enables a cushioning material having a plurality of unit structures U that occupy a cubic unit space to be laid out in a non-rectangular shaped area while eliminating unnecessary bias in the cushioning performance between individual parts by only slightly changing the shape of some or all of the plurality of unit structures U without major shape changes.

First, as shown in FIG. 15(A), the region in which the cushioning material is arranged is divided into region A1 in which it is possible to arrange the unit structures U as they are by adjusting the size of the unit structures U and increasing or decreasing the number of the unit structures U in at least one of the width, depth, and height directions, and region A2 in which this is difficult. Specifically, in this embodiment, the region in which the cushioning material 1A is arranged that extends linearly along the periphery of the inner and outer foot sides of the sole 110A corresponds to the region A1, and the region that extends curvedly along the periphery of the rear end side of the sole 110A corresponds to the region A2.

Here, in the region A1, a plurality of unit structures U occupying a unit space having a cubic shape with the lengths of the three sides adjusted to Lx, Ly, and Lz, as shown in FIG. 15(B), are arranged adjacent to each other. As a result, the region A1 is tiled with a plurality of unit structures U whose sizes have been adjusted, without any gaps.

On the other hand, in region A2, a plurality of unit structures U' are arranged adjacent to each other, each of which is configured to occupy a unit space whose shape has been modified so that a specific pair of three opposing faces are non-parallel to each other, as shown in FIG. 15(C). Here, the unit structure U' has been modified in shape to occupy a unit space after adjustment, for example, in which a pair of adjacent sides of the four sides of the unit space extending in the width direction have been adjusted to have a length Lx' that is slightly shorter than the length Lx of the other sides. Such a slight change in shape does not significantly change the cushioning performance of the unit structure.

The unit structures U' having this shape can be arranged side by side while individually adjusting their size and orientation, so that they can be laid out almost without gaps along the curved area A2. Therefore, by making only such a slight change in shape, the same cushioning performance as the area A1 can be achieved in the area A2.

Therefore, by adopting this design method, it becomes possible to lay out a cushioning material having a plurality of unit structures U each occupying a cubic unit space in a non-rectangular shaped area while eliminating unnecessary bias in the cushioning performance between individual parts by only slightly changing the shape of some or all of the plurality of unit structures U without making any major shape changes.

Therefore, if a cushioning material is designed according to this design method and then manufactured based on this design using a three-dimensional additive manufacturing device, it is easy to obtain cushioning materials with various external shapes that are constructed as a single component.

In the above-mentioned design method, when the cushioning material is laid in an area with a more complicated curved shape, it is sufficient to arrange multiple unit structures U1 adjacent to each other, each unit structure U1 being configured to occupy a unit space whose shape has been changed so that two specific pairs of faces out of three pairs of opposing faces are non-parallel to each other, as shown in Figure 15 (D).

Here, the unit structure U1 has been reshaped to occupy the adjusted unit space, for example by adjusting a pair of adjacent sides of the four sides of the unit space extending in the width direction to have a length Lx' that is slightly shorter than the length Lx of the other sides, and further adjusting a pair of adjacent sides of the four sides of the unit space extending in the height direction to have a length Lz' that is slightly shorter than the length Lz of the other sides. Such slight shape changes do not significantly change the cushioning performance of the unit structure.

The unit structures U1 having such a shape can be arranged side by side while individually adjusting their size and orientation, so that they can be laid out almost without gaps along the area of the complex curved shape described above. Therefore, by making only such a slight change in shape, the area can also exhibit the same cushioning performance as the area A1 described above.

In addition, in the above-mentioned design method, when the cushioning material is laid out in a linearly extending area, a plurality of unit structures U2 as shown in FIG. 15(E) may be arranged adjacent to each other instead of the unit structure U as shown in FIG. 15(B). Here, the unit structure U2 has three sets of opposing faces that are parallel, while the shape of a specific set of faces is adjusted to be a parallelogram, and the shape is modified to occupy the unit space after the adjustment.

In the illustrated unit structure U2, for example, a pair of faces located in the height direction are inclined along the width direction by an angle θ, so that the shape of the pair of faces is a parallelogram. Such a slight change in shape does not significantly change the cushioning performance of the unit structure. Therefore, even when the unit structures U2 are laid out, it is possible to layout the cushioning material without gaps while eliminating unnecessary bias in the cushioning performance from one area to another.

(Embodiment 4)
Fig. 16 is a schematic plan view showing the configuration of a sole according to embodiment 4. Fig. 17 is a cross-sectional view of the sole taken along line XVII-XVII shown in Fig. 16. Below, a sole 110B according to this embodiment will be described with reference to Figs. 16 and 17. The sole 110B according to this embodiment is provided in the shoe 100 according to embodiment 3, in place of the sole 110A described above.

16 and 17, the sole 110B has the same configuration as the sole 110A according to the third embodiment described above in that it includes a midsole 111, an outsole 112, and a cushioning material 1A, but the shape of the cushioning material 1A is different. Specifically, the midsole 111 has a cutout portion formed in the part of the midfoot R2 near the rear foot R3 and at a position corresponding to all parts of the rear foot R3, and the cushioning material 1A having a substantially D-shaped outline in a plan view is arranged so as to fill the cutout portion. In FIG. 16, to facilitate understanding, the arrangement area of the cushioning material 1A when the sole 110B is viewed in a plan view is light-colored. In other words, the cushioning material 1A has a cushioning area not only at the edge of the sole 110B but also in the inner area.

Here, the cushioning material 1A provided in the sole 110B is interposed between the midsole 111 and the outsole 112 so that, as described above, the layer LY1 formed by arranging a plurality of unit structures UA is disposed on the upper side of the sole 110B, and the layer LY2 formed by arranging a plurality of unit structures UB is disposed on the lower side of the sole 110B.

Therefore, even with this configuration, as in the case of the above-mentioned third embodiment, it is possible to obtain a lightweight sole with excellent cushioning and a shoe equipped with the sole, and the foot can be stably supported, particularly in the rear foot portion R3, when landing.

(First to fifth modified examples)
Figures 18 to 20 are cross-sectional views of the soles according to the first to third modified examples, respectively. Also, Figures 21 and 22 are schematic cross-sectional views showing the configurations of the soles according to the fourth and fifth modified examples, respectively. In Figures 21 and 22, the boundaries of a plurality of unit structures U (strictly speaking, the above-mentioned unit spaces) arranged in the buffer material are shown by lines. Hereinafter, the soles according to the first to fifth modified examples and the buffer materials 1A1 to 1A5 provided thereon will be described with reference to Figures 18 to 22.

As shown in Figures 18 and 19, the cushioning materials 1A1 and 1A2 provided in the soles of the first and second modified examples have a layer LY1 formed by an arrangement of multiple unit structures UA and a layer LY2 formed by an arrangement of multiple unit structures UB, similar to the cushioning material 1A provided in the sole 110B of the above-mentioned embodiment 4. On the other hand, the cushioning materials 1A1 and 1A2 provided in the sole of the first modified example differ from the cushioning material 1A provided in the sole 110B of the above-mentioned embodiment 4 in that the thicknesses of the layers LY1 and LY2 vary from one location to another.

That is, in the cushioning material 1A1 provided in the sole of the first modified example, the thickness of the layer LY1 is configured to gradually increase from the inner foot side (S1 side) to the outer foot side (S2), and in contrast, the thickness of the layer LY2 is configured to gradually decrease from the inner foot side to the outer foot side.

When configured in this way, it is possible to more stably support the foot, particularly on the medial side, when landing, making it possible to prevent the heel from collapsing inward more than necessary when landing, which is known as overpronation. Therefore, by making a sole according to this modified example and a shoe equipped with the sole, it is possible to provide a sole and a shoe equipped with the sole that are suitable for people who are prone to overpronation.

On the other hand, in the cushioning material 1A2 provided in the sole of the second modified example, the thickness of layer LY1 is large in the center between the inner and outer sides of the foot, while the thickness of layer LY2 is small in the center between the inner and outer sides of the foot.

When configured in this way, the center of the cushioning material deforms more when the foot lands, which increases the sense of support, especially for the heel. Therefore, by making a sole according to this modified example and a shoe equipped with the sole, it is possible to obtain a sole and a shoe equipped with the sole that can stably support the heel while improving the feel on the foot.

As shown in FIG. 20, the cushioning material 1A3 provided in the sole of the third modified example differs from the cushioning material 1A provided in the sole 110B of the above-described fourth embodiment in that it is made up of three types of unit structures having different external dimensions arranged in the height direction (i.e., Z direction).

Here, the outer height dimension of the unit structures arranged on the topmost layer LY1 is smaller than the outer height dimension of the unit structures arranged on the middle layer LY2, and the outer height dimension of the unit structures arranged on the middle layer LY2 is smaller than the outer height dimension of the unit structures arranged on the bottommost layer LY3.

As a result, the layer LY1 located at the top has a relatively low compressive stiffness, the layer LY3 located at the bottom has a relatively high compressive stiffness, and the layer LY2 located in the middle has a compressive stiffness between the compressive stiffnesses of the layers LY1 and LY2. Therefore, the layer LY1 is a relatively soft part, and the layer LY3 is a relatively hard part, with the layer LY3 having a hardness between them.

Therefore, even with this configuration, as in the case of the above-mentioned embodiment 4, it is possible to obtain a lightweight sole with excellent cushioning and a shoe equipped with the sole, and the foot can be stably supported, particularly in the rear foot portion R3, when landing.

As shown in Figures 21 and 22, the cushioning materials 1A4 and 1A5 provided in the soles of the fourth and fifth modified examples differ from the cushioning material 1A provided in the sole 110B of the above-mentioned fourth embodiment in that multiple types of unit structures having different external dimensions are arranged in a direction perpendicular to the height direction (i.e., the Z direction).

Here, the cushioning material 1A4 provided in the sole of the fourth modified example is configured such that the boundaries between the multiple unit structures U (strictly speaking, the unit spaces described above) are inclined, so that the unit structures U are configured so that the external dimensions of each unit structure differ from each other. On the other hand, the cushioning material 1A5 provided in the sole of the fifth modified example is configured such that the boundaries between the multiple unit structures U (strictly speaking, the unit spaces described above) are curved, so that the unit structures U are configured so that the external dimensions of each unit structure differ from each other (particularly, the external dimensions of the unit structures located at both ends and the unit structures located in the center shown in the figure are different).

Even with this configuration, as in the case of the above-mentioned fourth embodiment, it is possible to obtain a lightweight sole with excellent cushioning and a shoe equipped with the sole, and the foot can be stably supported, particularly in the rear foot portion R3, when landing. Furthermore, by adopting this configuration, it is also possible to adjust the cushioning performance in various ways for each part.

(Embodiment 5)
Fig. 23 is a schematic plan view showing the configuration of a sole according to embodiment 5. Fig. 24 is a cross-sectional view of the sole taken along line XXIV-XXIV in Fig. 23. Below, a sole 110C according to this embodiment will be described with reference to Figs. 23 and 24. The sole 110C according to this embodiment is provided in the shoe 100 according to embodiment 3, in place of the sole 110A described above.

23 and 24, the shape of the cushioning material 1A of the sole 110C is different from that of the sole 110A according to the third embodiment described above, and the entire midsole 111 is made of the cushioning material 1A. That is, in the sole 110C according to the present embodiment, a midsole made of a separate material from the cushioning material 1A is not provided, and the cushioning material 1A itself constitutes the midsole 111. Therefore, the midsole 111 is configured to cover the upper part of the outsole 112, and its upper part is joined to the upper 120 (see FIG. 11, etc.). In FIG. 23, for ease of understanding, the arrangement area of the cushioning material 1A when the sole 110C is viewed from above is lightly colored. That is, the cushioning material 1A has a cushioning area not only on the edge of the sole 110C but also on the inside of it.

Here, the cushioning material 1A provided on the sole 110C is provided on the outsole 112 so that, as described above, the layer LY1 formed by arranging a plurality of unit structures UA is disposed on the upper side of the sole 110B, and the layer LY2 formed by arranging a plurality of unit structures UB is disposed on the lower side of the sole 110B.

Therefore, even with this configuration, as in the case of the above-mentioned third embodiment, it is possible to obtain a sole that is lightweight and has excellent cushioning properties, and a shoe equipped with the sole, and the entire foot (i.e., all areas of the forefoot R1, midfoot R2, and rearfoot R3) can be stably supported, especially when landing.

(Sixth and Seventh Modifications)
25 and 26 are cross-sectional views of the soles according to the sixth and seventh modified examples, respectively. Hereinafter, the sixth and seventh modified examples of the shoe soles and the cushioning materials 1A6 and 1A7 provided thereon will be described with reference to these Figs. 25 and 26.

As shown in Figures 25 and 26, the cushioning materials 1A6 and 1A7 provided in the soles of the sixth and seventh modified examples are, like the cushioning material 1A provided in the sole of the fifth embodiment described above, the cushioning materials 1A6 and 1A7 themselves constitute the midsole 111, but the internal structure of the cushioning materials 1A6 and 1A7 is different from that of the cushioning material 1A provided in the sole of the fifth embodiment described above.

In other words, in the cushioning material 1A6 provided in the sole of the sixth modified example, the layer LY1 to be placed on the upper side of the sole is composed of an arrangement of multiple unit structures UB (see FIG. 1, etc.), and the layer LY2 to be placed on the lower side of the sole is composed of an arrangement of multiple unit structures UA (see FIG. 1, etc.). As a result, the layer LY1 placed on the upper side of the sole is composed of a relatively high compression stiffness, and the layer LY2 placed on the lower side of the sole is composed of a relatively low compression stiffness. Therefore, the layer LY1 is a relatively hard part, and the layer LY2 is a relatively soft part.

When configured in this way, the curved shape of the sole is more easily maintained when running, which reduces the amount of work done on the ankle joint when pushing off, resulting in an energy-saving sole and a shoe equipped with the sole.

On the other hand, the cushioning material 1A7 provided in the sole of the seventh modified example has a layer LY1 formed by arranging a plurality of unit structures UA and a layer LY2 formed by arranging a plurality of unit structures UB, similar to the cushioning material 1A provided in the sole of the above-mentioned embodiment 5, but in addition to this, a plate-shaped partition portion 50 is provided between these layers LY1 and LY2.

Although this plate-shaped partition portion 50 is not a part of the wall 10 (see FIG. 1, etc.) that defines the unit structures UA, UB included in the cushioning material 1A7, it is integrated with the unit structures UA, UB. As a result, the plate-shaped partition portion 50 embedded inside the cushioning material 1A7 separates unit structures with different external dimensions.

When configured in this way, the partition wall 50 is provided inside the cushioning material 1A7, improving the bending and torsional rigidity of the entire sole, making it possible to create a sole and a shoe equipped with the sole that is particularly suitable for sports that require high-speed running and turning movements.

(Embodiment 6)
Fig. 27 is a schematic plan view showing the configuration of a shoe sole according to the sixth embodiment. Figs. 28 and 29 are cross-sectional views of the shoe sole taken along lines XXVIII-XXVIII and XXIX-XXIX in Fig. 27, respectively. In Figs. 28 and 29, the boundaries of a plurality of unit structures U (strictly speaking, the above-mentioned unit spaces) arranged on the buffer material are shown by lines. Hereinafter, a shoe sole 110D according to this embodiment will be described with reference to Figs. 27 to 29. The shoe sole 110D according to this embodiment is provided in the shoe 100 according to the third embodiment in place of the above-mentioned sole 110A.

As shown in Figures 27 to 29, the sole 110D has a cushioning material 1C with a different configuration from the cushioning material 1A of the sole 110A according to the third embodiment described above. Specifically, the cushioning material 1C is interposed between the midsole 111 and the outsole 112 so as to be located in the entire area of the sole 110D when viewed from above (i.e., all of the forefoot portion R1, midfoot portion R2, and rearfoot portion R3). In Figure 27, for ease of understanding, the area where the cushioning material 1C is located when the sole 110D is viewed from above is light-colored.

Here, the cushioning material 1C provided on the sole 110D has a cushioning region made up of the above-mentioned three-dimensional structure S over its entire area when viewed in a plane, and as shown in Figures 28 and 29, the three-dimensional structure S has an upper layer LY1 and a lower layer LY2. In the upper layer LY1 and the lower layer LY2, unit structures U are arranged side by side in a direction intersecting the height direction (Z direction shown in the figure).

When viewed in a plan view, the cushioning material 1C is roughly divided into three zones SC1 to SC3 based on the difference in its configuration. More specifically, zone SC1 corresponds to the part on the inner side of the midfoot part R2, zone SC2 corresponds to the part on the outer side of the rearfoot part R3 and the rear part on the outer side of the midfoot part R2, and zone SC3 corresponds to the part excluding zones SC1 and SC2.

28, the area SC1 is configured to be a harder area compared to the area SC3 , and specifically, the outer dimensions of the unit structures U included in the area SC1 are different from the outer dimensions of the unit structures U included in the area SC3 . More specifically, in a direction intersecting the axial direction (Z direction shown in the figure), which is the direction in which the cushioning material 1C exerts its cushioning function by receiving a load, the outer dimensions of the unit structures U included in the area SC1 are configured to be smaller than the outer dimensions of the unit structures U included in the area SC3 .

29, the area SC2 is configured to be a softer area than the area SC3 , and specifically, the outer dimensions of the unit structures U included in the area SC2 are different from the outer dimensions of the unit structures U included in the area SC3 . More specifically, in the axial direction (Z direction shown in the figure), which is the direction in which the cushioning material 1C exerts its cushioning function by receiving a load, the outer dimensions of the unit structures U included in the area SC2 are configured to be larger than the outer dimensions of the unit structures U included in the area SC3 , while in the direction intersecting the axial direction, the outer dimensions of the unit structures U included in the area SC2 are configured to be larger than the outer dimensions of the unit structures U included in the area SC3 .

Therefore, by configuring it in this way, the compression stiffness of the cushioning material 1C can be changed for each area, and the compression stiffness can be increased relatively in the order of area SC2, area SC3, and area SC1.

As a result, the compressive stiffness of the medial side of the midfoot portion R2 around the area Q3 of the sole 110D that supports the calcaneus bone is relatively high, while the compressive stiffness of the lateral side rear portion of the midfoot portion R2 and the lateral side portion of the rearfoot portion R3 is relatively low.

This configuration makes it possible to prevent the occurrence of so-called overpronation, in which the heel collapses inward more than necessary when landing. In other words, when a person who is prone to overpronation wears a shoe 100 equipped with a sole 110D according to this embodiment, the sole of the foot can be stably supported by the rear part of the medial side of the midfoot R2, which in turn makes it possible to distribute the pressure acting on the midsole 111 and prevent excessive deformation of the midsole 111, thereby preventing the occurrence of overpronation.

In addition, with this configuration, as described above, it is possible to stably support the sole of the foot at the rear part on the medial side of the midfoot portion R2, which in turn makes it possible to distribute the pressure acting on the midsole 111 and prevent excessive deformation of the midsole 111. When a person with flat feet wears a shoe 100 equipped with the sole 110D of this embodiment, they can avoid the concentration of pressure on the medial side of the foot when landing.

On the other hand, by configuring it as described above, the cushioning material 1C deforms more significantly when landing in the rear part on the outside side of the midfoot part R2 and the outside side of the rear foot part R3, making it possible to significantly reduce the impact on the sole of the foot when landing.

Therefore, by making the sole 110D according to this embodiment and the shoe 100 equipped with the sole, it is possible to obtain a sole and a shoe equipped with the sole that is particularly suitable for people who are prone to overpronation or people with flat feet, has excellent stability when landing, feels good on the foot, and is lightweight.

(Seventh embodiment)
Fig. 30 is a schematic plan view showing the configuration of a sole according to the seventh embodiment. Fig. 31 is a cross-sectional view of the sole along the line XXXI-XXXI shown in Fig. 30. Note that in Fig. 31, the boundaries of a plurality of unit structures U (strictly speaking, the above-mentioned unit spaces) arranged in the buffer material are shown by lines. Below, a sole 110E according to this embodiment will be described with reference to Figs. 30 and 31. Note that the sole 110E according to this embodiment is provided in the shoe 100 according to the third embodiment in place of the above-mentioned sole 110A.

As shown in Figures 30 and 31, the sole 110E has a cushioning material 1D with a different configuration from the cushioning material 1A that the sole 110A according to the third embodiment has. Specifically, the cushioning material 1D is interposed between the midsole 111 and the outsole 112 so as to be located in the entire area of the sole 110E when viewed from above (i.e., all of the forefoot portion R1, midfoot portion R2, and rearfoot portion R3). In Figure 30, to make it easier to understand, the area where the cushioning material 1D is located when the sole 110E is viewed from above is light-colored.

Here, the cushioning material 1D provided on the sole 110E has a cushioning region made up of the above-mentioned three-dimensional structure S over its entire area when viewed in a plane, and as shown in FIG. 30, the three-dimensional structure S has an upper layer LY1 and a lower layer LY2. In the upper layer LY1 and the lower layer LY2, unit structures U are arranged side by side in a direction intersecting the height direction (Z direction shown in the figure).

When viewed from above, the cushioning material 1D is roughly divided into two areas SC1 and SC2 based on the difference in its configuration. More specifically, area SC1 corresponds to the rear part on the outer side of the forefoot part R1, the outer side of the midfoot part R2, and the front part on the outer side of the rearfoot part R3, and area SC2 corresponds to the part excluding area SC1.

As shown in FIG. 31, area SC1 is configured to be a harder area than area SC2, and specifically, the outer dimensions of the unit structures U included in area SC1 are different from the outer dimensions of the unit structures U included in area SC2. More specifically, in the direction intersecting the axial direction (Z direction shown in the figure), which is the direction in which the cushioning material 1D exerts its cushioning function by receiving a load, the outer dimensions of the unit structures U included in area SC1 are configured to be smaller than the outer dimensions of the unit structures U included in area SC2.

Therefore, by configuring it in this way, the compression stiffness of the cushioning material 1D can be changed for each zone, and the compression stiffness can be increased relatively in the order of zone SC2 and zone SC1.

As a result, in the sole 110E, around the area Q3 that supports the calcaneus bone and the area Q2 that supports the little toe, the compression stiffness of the rear part on the outside side of the forefoot part R1, the outside side of the midfoot part R2, and the outside side of the rearfoot part R3 is relatively high, while the compression stiffness of the part on the inside side of the forefoot part R1 is relatively low.

This configuration makes it possible to prevent the occurrence of so-called underpronation, in which the heel does not collapse sufficiently inward when landing. In other words, when a person who is prone to underpronation wears a shoe 100 equipped with the sole 110E of this embodiment, the sole of the foot can be stably supported on the outer side of the foot, and as a result, the pressure acting on the midsole 111 can be dispersed, preventing excessive deformation of the midsole 111, and as a result, preventing the occurrence of underpronation.

In addition, by configuring it in this way, as described above, it is possible to stably support the sole of the foot on the outer side, and accordingly, it is possible to distribute the pressure acting on the midsole 111 and prevent excessive deformation of the midsole 111. Therefore, when a person with bow legs wears the shoe 100 equipped with the sole 110E according to this embodiment, it is possible to avoid the concentration of stress on the outer side of the foot when landing.

On the other hand, by configuring it as described above, the cushioning material 1D deforms more significantly on the inner side of the foot when the foot lands, making it possible to significantly reduce the impact on the sole of the foot when the foot lands.

Therefore, by making the sole 110E according to this embodiment and the shoe 100 equipped with the sole, it is possible to obtain a sole and a shoe equipped with the sole that is particularly suitable for people who are prone to underpronation or people with bow legs, and that has excellent stability when landing, a good feel on the foot, and is lightweight.

(Summary of the contents disclosed in the embodiments, etc.)
The characteristic configurations disclosed in the above-mentioned first to seventh embodiments and their modifications can be summarized as follows.

The cushioning material according to one aspect of the present disclosure includes a three-dimensional structure in which unit structures are three-dimensional shapes formed by walls whose outer shape is defined by a pair of parallel planes or curved surfaces, and the unit structures are arranged regularly and continuously in at least one direction. In the cushioning material according to the present invention, when the hexahedral space occupied by each of the unit structures is referred to as a unit space, the three-dimensional structure includes unit structures in which the outer dimensions of the unit spaces are different.

In a cushioning material according to a certain aspect of the present disclosure, the unit structures having different outer dimensions of the unit space may be located at least in the axial direction in which the cushioning material exerts its cushioning function by receiving a load.

In a cushioning material according to a certain aspect of the present disclosure, the unit structures having different outer dimensions of the unit space may be located in a direction that intersects at least the axial direction in which the cushioning material exerts its cushioning function by receiving a load.

In a cushioning material according to an aspect of the present disclosure, a partition wall portion that does not correspond to the wall that defines the unit structure may be provided between unit structures that have different outer dimensions of the unit space.

In a cushioning material according to a certain aspect of the present disclosure, when the outer dimension of the unit space in the axial direction in which the cushioning material exerts a cushioning function by receiving a load is L1, and the larger outer dimension of the outer dimensions of the unit space in two axial directions perpendicular to the axial direction is L2, at least one of the unit structures having different outer dimensions of the unit spaces may satisfy the condition 1.1≦L1/L2≦4.0.

In a cushioning material according to a certain aspect of the present disclosure, when the outer dimension of the unit space in the axial direction in which the cushioning material exerts a cushioning function by receiving a load is L1, and the larger outer dimension of the outer dimensions of the unit space in two axial directions perpendicular to the axial direction is L2, at least one of the unit structures having different outer dimensions of the unit spaces may satisfy the condition 0.1≦L1/L2≦0.9.

In a cushioning material according to an embodiment of the present disclosure, the three-dimensional structure may be configured by adding thickness based on a triple periodic minimal surface.

In a cushioning material according to an embodiment of the present disclosure, the three-dimensional structure may have a Schwartz P structure, a gyroid structure, or a Schwartz D structure.

In a cushioning material according to a certain aspect of the present disclosure, the three-dimensional structure may be configured with a thickness based on a plurality of planes arranged to intersect with each other so as to have a cavity inside.

In a cushioning material according to an embodiment of the present disclosure, the three-dimensional structure may have an octet structure, a cubic structure, or a cubic octet structure.

The cushioning material according to one aspect of the present disclosure may be made of either a resin material or a rubber material.

The buffer material according to an embodiment of the present disclosure may be composed of a polymer composition containing one or more polymers selected from the group consisting of olefin-based polymers, amide-based polymers, ester-based polymers, urethane-based polymers, styrene-based polymers, acrylic polymers, and methacrylic polymers.

The sole according to one aspect of the present disclosure is provided with the cushioning material according to one aspect of the present disclosure described above.

In a sole according to one aspect of the present disclosure, the cushioning material may be arranged so that the axial direction in which the cushioning material exerts its cushioning function when loaded is perpendicular to the ground surface.

A shoe according to an embodiment of the present disclosure comprises a sole according to an embodiment of the present disclosure described above and an upper provided above the sole.

(Other forms, etc.)
In the above-mentioned first to seventh embodiments and their modified examples, the case where the buffer material is constituted only by a three-dimensional structure as a buffer region has been described as an example, but a support part having, for example, a plate shape may be provided separately at an end of the three-dimensional structure located in the axial direction where the buffer material exerts a buffer function by receiving a load. The support part may be provided only at one of a pair of ends located in the axial direction, or may be provided at both of them. In this case, the support part may be a separate member from the three-dimensional structure part and assembled to the three-dimensional structure by adhesion or the like, or may be molded integrally with the three-dimensional structure.

Here, in the soles and shoes as shown in the above-mentioned embodiments 3 to 7 and their modified examples, when a support part is provided as described above, the support part may be fixed by adhesion or the like to the midsole, outsole, upper body, etc. that will be disposed opposite it. On the other hand, when a support part as described above is provided on the ground-contact surface side of the cushioning material, the support part itself may function as an outsole, thereby eliminating the need to provide an outsole made of a separate member.

In addition, the three-dimensional structure serving as the buffer region may be provided locally with an irregularly shaped portion that does not correspond to the wall that defines the unit structure. By providing this irregularly shaped portion, the compression performance and deformability can be adjusted for each part of the buffer material. This irregularly shaped portion may be provided at the end of the buffer material, or in an area inside the end. For example, when providing an irregularly shaped portion at the end of the buffer material, a cover-like irregularly shaped portion can be provided to block some or all of the multiple openings located at the end of the buffer material. With this configuration, the compression performance and deformability can be adjusted at the end of the buffer material.

Therefore, by adjusting the outer dimensions of the unit structures for each part of the cushioning material and providing irregularly shaped parts in specific parts of the cushioning material, it is possible to manufacture cushioning materials with various cushioning functions with a high degree of design freedom by changing the combinations in various ways. In particular, for cushioning materials to be provided in shoe soles, it is possible to easily manufacture cushioning materials with the desired cushioning functions by adjusting the outer dimensions of the unit structures for each part of the cushioning material and by changing the presence or absence, shape, thickness, etc. of the cover-like irregularly shaped parts described above at the ends of the cushioning material.

In the above-mentioned third to seventh embodiments and their modified examples, the cushioning material is provided on all or part of the sole in plan view, but the location of the cushioning material is not limited to the layouts specifically exemplified in these embodiments and modified examples. For example, depending on the type of sport or purpose for which the shoe is used, the cushioning material may be provided only on either the inner or outer part of the sole, or only on a partial area along the edge of the sole (the partial area may be provided independently of each other). The cushioning material may also be provided between the midsole and the upper. Here, when the cushioning material is provided on the entire surface of the sole, the entire sole may be replaced with the cushioning material instead of the midsole.

In the above-mentioned third to seventh embodiments and their modified examples, a cushioning material configured to be stacked in multiple layers in the axial direction in which the cushioning material exerts its cushioning function when loaded, has been described as being applied to a sole and a shoe equipped with the same. However, a cushioning material configured to be only one layer without being stacked along the axial direction can also be applied to a sole and a shoe equipped with the same. In that case, it is sufficient if the layer includes unit structures having partially different external dimensions. As an example, the unit structures may be configured to have different external dimensions on the inner foot side and the outer foot side of the sole, or the unit structures may be configured to have different external dimensions on the forefoot, midfoot, and rearfoot parts of the sole.

In particular, in the fourth and fifth modified examples and the sixth and seventh embodiments described above, the boundaries of the multiple unit structures arranged on the cushioning material are all configured in straight lines (see Figures 21, 22, 28, 29, 31, etc.), but the boundaries do not necessarily have to be straight lines and can be modified in various ways to suit the use and design of the cushioning material (particularly the design of the sole when applied to shoes), and as one example, they can be curved.

The thickness of the wall of the cushioning material may be varied depending on the placement position on the sole, and the surface structure of the cushioning material may be varied depending on the placement position on the sole. For example, a cushioning material with a Schwarz P surface structure may be placed in one part of the sole, and a cushioning material with a gyroid surface structure may be placed in another part of the sole.

In addition, in the above-mentioned third to seventh embodiments and their modified examples, the present invention has been described as being applied to a shoe that has a shoe tongue and shoe laces, but the present invention may also be applied to shoes that do not have these features (such as shoes with a sock-like upper) and the soles that are provided therefor.

Furthermore, in the above-mentioned third to seventh embodiments and their modifications, the cushioning material according to the present invention has been described as being applied to the soles of shoes, but the cushioning material according to the present invention can be used for other cushioning purposes. For example, the cushioning material according to the present invention can be used for various purposes such as packaging material, flooring material for buildings (such as houses), surface material for paved roads, surface material for sofas and chairs, tires, etc.

Furthermore, the characteristic configurations disclosed in the above-mentioned embodiments 1 to 7 and their variations can be combined with each other without departing from the spirit of the present invention.

As such, the above-described embodiments and their variations disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the claims, and includes all modifications that are equivalent in meaning and scope to the claims.

1A-1D, 1A1-1A7: Cushioning material, 10: Wall, 11: Serpentine section, 12: Turning point, 13: Inside corner, 14: Outside corner, 50: Partition, 100: Shoe, 110A-110E: Sole, 111: Midsole, 112: Outsole, 112a: Ground surface, 120: Upper, 121: Upper body, 122: Shoe tongue, 123: Shoelace, Q1: Part supporting the big toe, Q2: Part supporting the little toe, Q3: Part supporting the calcaneus, R1: Forefoot, R2: Midfoot, R3: Rearfoot, S: Three-dimensional structure, U, U', UA, UB, U1, U2: Unit structure.

Claims (7)

A shoe sole comprising a forefoot portion supporting the toes and plantar fascia of a wearer's foot, a midfoot portion supporting the arch of the wearer's foot, and a rearfoot portion supporting the heel of the wearer's foot, the sole having a ground contact surface on the underside thereof,
A cushioning material is provided at least across the midfoot portion and the rearfoot portion,
The buffer material includes a three-dimensional structure in which a unit structure is a three-dimensional shape formed by a wall whose outer shape is defined by a pair of parallel planes or curved surfaces, and the unit structures are regularly and continuously arranged in at least one direction;
The three-dimensional structure is formed by adding a thickness to a triply periodic minimal curved surface,
When a hexahedral space occupied by each of the unit structures is referred to as a unit space, the cushioning material is
a first region that is a region corresponding to an inner part of the midfoot portion and that is configured with a plurality of first unit structures, the size of the unit space in a direction parallel to the ground surface being a first size;
the size of the unit space in a direction parallel to the ground contact surface being a second size larger than the first size, and a second area corresponding to an outer side portion of the rear foot portion and a rear part of the outer side of the midfoot portion. The cushioning material is
The sole of claim 1, further comprising a third region, the third region being a region corresponding to the midfoot and rearfoot portions excluding the first region and the second region, and being composed of a plurality of third unit structures, the size of the unit space in a direction parallel to the ground contact surface being a third size that is larger than the first size and smaller than the second size. The shoe sole according to claim 1 , wherein the three-dimensional structure has a Schwarz P structure, a gyroid structure, or a Schwarz D structure. A shoe sole comprising a forefoot portion supporting the toes and plantar fascia of a wearer's foot, a midfoot portion supporting the arch of the wearer's foot, and a rearfoot portion supporting the heel of the wearer's foot, the sole having a ground contact surface on the underside thereof,
A cushioning material is provided at least across the midfoot portion and the rearfoot portion,
The buffer material includes a three-dimensional structure in which a unit structure is a three-dimensional shape formed by a wall whose outer shape is defined by a pair of parallel planes or curved surfaces, and the unit structures are regularly and continuously arranged in at least one direction;
The three-dimensional structure is formed by adding thickness to a plurality of planes arranged to intersect with each other so as to have a cavity therein,
When a hexahedral space occupied by each of the unit structures is referred to as a unit space, the cushioning material is
a first region that is a region corresponding to an inner part of the midfoot portion and that is configured with a plurality of first unit structures, the size of the unit space in a direction parallel to the ground surface being a first size;
the size of the unit space in a direction parallel to the ground contact surface being a second size larger than the first size, and a second area corresponding to an outer side portion of the rear foot portion and a rear part of the outer side of the midfoot portion. The cushioning material is
The sole of claim 4, further comprising a third region, the third region being a region corresponding to the midfoot and rearfoot portions excluding the first region and the second region, and being composed of a plurality of third unit structures, the size of the unit space in a direction parallel to the ground contact surface being a third size that is larger than the first size and smaller than the second size. The sole according to claim 4 , wherein the three-dimensional structure has an octet structure, a cubic structure, or a cubic octet structure. A shoe sole according to any one of claims 1 to 6 ,
and an upper provided above the sole.

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