SHOE SOLE AND SHOE INCLUDING THE SAME

Abstract

A shoe sole includes a cushion layer, an upper-side plate, and a lower-side plate. The cushion layer includes: a first region configured to support a metatarsophalangeal (MP) joint of a foot of a wearer; and a second region included in a portion located on a rear side with respect to the first region and located on a front side with respect to the rearfoot portion. The second region includes: a third region located in a central portion in a left-right direction; a fourth region located in a medial foot-side end portion in the left-right direction; and a fifth region located in a lateral foot-side end portion in the left-right direction. The fourth region and the fifth region are lower in compression rigidity than the first region, and the third region is lower in compression rigidity than the fourth region and the fifth region.

Claims

1. A shoe sole including: a forefoot portion configured to support a toe portion and a ball portion of a foot of a wearer; a midfoot portion configured to support an arch portion of the foot of the wearer; and a rearfoot portion configured to support a heel portion of the foot of the wearer, the forefoot portion, the midfoot portion, and the rearfoot portion being connected in a front-rear direction corresponding to a foot length direction of the foot of the wearer, the shoe sole having: an upper-side surface configured as a supporting surface for supporting a bottom of the foot of the wearer; and a lower-side surface configured as a ground contact surface, the shoe sole comprising: a cushion layer located to extend in the forefoot portion, the midfoot portion, and the rearfoot portion; an upper-side plate located close to the supporting surface with respect to the cushion layer to cover an upper-side surface of the cushion layer, the upper-side plate being located to extend in at least the forefoot portion and the midfoot portion; and a lower-side plate located close to the ground contact surface with respect to the cushion layer to cover a lower-side surface of the cushion layer, the lower-side plate being located to extend in at least the forefoot portion and the midfoot portion, wherein the cushion layer includes a first region configured to support a metatarsophalangeal (MP) joint of the foot of the wearer, and a second region included in a portion located on a rear side with respect to the first region in the front-rear direction and located on a front side with respect to the rearfoot portion in the front-rear direction, the second region includes a third region located in a central portion in a left-right direction corresponding to a foot width direction of the foot of the wearer, a fourth region located in a medial foot-side end portion in the left-right direction, and a fifth region located in a lateral foot-side end portion in the left-right direction, the fourth region and the fifth region are lower in compression rigidity than the first region, and the third region is lower in compression rigidity than the fourth region and the fifth region.

2. The shoe sole according to claim 1, wherein the cushion layer includes a first cushion member disposed at least in a portion of the cushion layer to form the first region, the portion of the cushion layer being configured to support the MP joint of the foot of the wearer, and a second cushion member disposed to at least extend in a portion included in the midfoot portion of the cushion layer and a portion included in the rearfoot portion of the cushion layer to form the second region, the second cushion member has a shape bifurcating forward in the front-rear direction, the shape including a medial foot-side branch portion extending to the medial foot-side end portion on the front side with respect to the rearfoot portion in the front-rear direction, and a lateral foot-side branch portion extending to the lateral foot-side end portion on the front side with respect to the rearfoot portion in the front-rear direction, the fourth region is formed of the medial foot-side branch portion of the second cushion member, the fifth region is formed of the lateral foot-side branch portion of the second cushion member, and the third region is formed of a gap portion provided between the medial foot-side branch portion and the lateral foot-side branch portion in the second cushion member.

3. The shoe sole according to claim 2, wherein the first cushion member is formed of a three-dimensional structure made of resin or rubber, the three-dimensional structure including a unit structure body having a three-dimensional shape formed by a wall having an outer shape defined by a pair of parallel flat or curved surfaces, the three-dimensional structure being formed of a plurality of the unit structure bodies repeatedly arranged to be adjacent to each other, and the second cushion member is configured of a plate-shaped or block-shaped member formed of a foam material made of resin or rubber.

4. The shoe sole according to claim 3, wherein the unit structure body is formed by adding a thickness to each of divided structure units obtained by dividing a structure unit into two structure units in one of orthogonal three-axis directions, the structure unit being formed of a plurality of flat surfaces disposed to intersect with each other so as to be hollow inside.

5. The shoe sole according to claim 4, wherein the structure unit has one of a Kelvin structure, an octet structure, a cubic structure, and a cubic-octet structure.

6. The shoe sole according to claim 3, wherein the unit structure body is formed by adding a thickness to each of divided structure units obtained by dividing a structure unit having a triply periodic minimal surface into two structure units in one of orthogonal three-axis directions.

7. The shoe sole according to claim 6, wherein the structure unit has one of a Schwartz P structure, a gyroid structure, and a Schwartz D structure.

8. The shoe sole according to claim 1, wherein a first rib extending along a medial foot-side edge portion of the shoe sole is provided in a portion included in a medial foot-side end portion of the midfoot portion on a lower-side surface of the lower-side plate, and a second rib extending along a lateral foot-side edge portion of the shoe sole is provided in a portion included in a lateral foot-side end portion of the midfoot portion on the lower-side surface of the lower-side plate.

9. The shoe sole according to claim 8, wherein each of the first rib and the second rib is formed by forming the lower-side plate to be locally thicker than other portions.

10. The shoe sole according to claim 1, wherein at least one of a portion included in the forefoot portion of the upper-side plate and a portion included in the forefoot portion of the lower-side plate has a curved shape having a central portion bulging downward with respect to the medial foot-side end portion and the lateral foot-side end portion in the left-right direction.

11. The shoe sole according to claim 1, wherein the lower-side plate is a spike plate provided with spikes, and a lower-side surface of the lower-side plate forms the ground contact surface.

12. A shoe comprising: the shoe sole according to claim 1; and an upper provided above the shoe sole.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a perspective view of a shoe according to an embodiment.

[0013] FIG. 2 is a plan view of a shoe sole shown in FIG. 1.

[0014] FIG. 3 is a bottom view of the shoe sole shown in FIG. 1.

[0015] FIG. 4 is a side view of the shoe sole shown in FIG. 1 as viewed from a medial foot side.

[0016] FIG. 5 is a side view of the shoe sole shown in FIG. 1 as viewed from a lateral foot side.

[0017] FIG. 6 is a perspective view of the shoe sole shown in FIG. 1.

[0018] FIG. 7 is an exploded perspective view of the shoe sole shown in FIG. 1.

[0019] FIG. 8A is a perspective view of a cushion member having basically the same structure as that of a first cushion member included in the shoe sole shown in FIG. 1.

[0020] FIG. 8B is a perspective view of a unit structure body of the cushion member shown in FIG. 8A.

[0021] FIG. 9A is a perspective view of a cushion member similar in structure to the first cushion member included in the shoe sole shown in FIG. 1.

[0022] FIG. 9B is a perspective view of a unit structure body of the cushion member shown in FIG. 9A.

[0023] FIG. 10 is a perspective view showing a state of the shoe sole shown in FIG. 1 from which an additional cushion member and an upper-side plate have been removed.

[0024] FIG. 11 is a plan view showing a state of the shoe sole shown in FIG. 1 from which the additional cushion member and the upper-side plate have been removed.

[0025] FIG. 12 is a schematic cross-sectional view of the shoe sole shown in FIG. 1 taken along a line XII-XII shown in FIG. 3.

[0026] FIG. 13A is a schematic cross-sectional view of the shoe sole shown in FIG. 1 taken along a line XIIIA-XIIIA shown in FIG. 3.

[0027] FIG. 13B is a schematic cross-sectional view of the shoe sole shown in FIG. 1 taken along a line XIIIB-XIIIB shown in FIG. 3.

[0028] FIG. 13C is a schematic cross-sectional view of the shoe sole shown in FIG. 1 taken along a line XIIIC-XIIIC shown in FIG. 3.

[0029] FIG. 14 is a schematic plan view showing compression rigidity in each part of a cushion layer included in the shoe sole shown in FIG. 1.

DETAILED DESCRIPTION

[0030] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In the embodiments described below, the same or common portions are denoted by the same reference characters in the drawings, and the description thereof will not be repeated. Note that a shoe and a shoe sole provided therein according to the embodiment described below are a spike shoe intended to be used exclusively for short-distance sports and a shoe sole provided therein.

Embodiments

[0031] FIG. 1 is a perspective view of a shoe according to an embodiment. FIGS. 2 and 3 are a plan view and a bottom view, respectively, of a shoe sole according to the embodiment. FIGS. 4 and 5 are side views of the shoe sole as viewed from a medial foot side and a lateral foot side, respectively. FIG. 6 is a perspective view of the shoe sole according to the embodiment, and FIG. 7 is an exploded perspective view of the shoe sole. First, schematic configurations of a shoe 1 and a shoe sole 10 according to the present embodiment will be hereinafter described with reference to FIGS. 1 to 7.

[0032] As shown in FIG. 1, the shoe 1 includes the shoe sole 10 and an upper 60. The shoe sole 10 having a substantially flat shape includes: a supporting surface 10a (see FIGS. 2, 4, 5, and the like) that supports a bottom of a foot of a wearer; and a ground contact surface 10b that lands on the ground during use such as during walking and running. The upper 60 is located above the shoe sole 10 and shaped to cover the substantially entire portion extending from an ankle of the inserted wearer's foot to a distal end. The upper 60 is joined to the shoe sole 10, for example, by bonding or the like.

[0033] In this case, the front-rear direction of the shoe sole 10 is defined as a direction corresponding to the foot length direction of the foot of the wearer who wears the shoe 1 including the shoe sole 10. The left-right direction of the shoe sole 10 is defined as a direction corresponding to the foot width direction of the foot of the wearer wearing the shoe 1. Further, the up-down direction of the shoe sole 10 is defined as a direction orthogonal to both the front-rear direction and the left-right direction.

[0034] As shown in FIGS. 2 to 5, the shoe sole 10 includes a forefoot portion R1, a midfoot portion R2, and a rearfoot portion R3 in the front-rear direction. The forefoot portion R1 is configured to support a toe portion and a ball portion of the wearer's foot, the midfoot portion R2 is configured to support an arch portion of the wearer's foot, and the rearfoot portion R3 is configured to support a heel portion of the wearer's foot.

[0035] The forefoot portion R1, the midfoot portion R2, and the rearfoot portion R3 are defined as follows based on a shoe center SC (see FIGS. 2 and 3) of the shoe 1. In this case, the shoe center SC is an imaginary straight line obtained by projecting a straight line onto the shoe sole 10 in the up-down direction in the state in which a standard wearer having a foot size suitable for the shoe 1 wears the shoe 1, the straight line connecting a central portion of a calcaneus bone (what is called a heel center (the heel center is indicated by a reference character HC in FIGS. 3 and 4)) to a portion between the first toe and the second toe of this standard wearer. The direction in which the shoe center SC extends corresponds to the above-mentioned front-rear direction. As a precondition, the foremost end and the rearmost end of the supporting surface 10a in the front-rear direction that are located on the shoe center SC are referred to as a front-side end position PF and a rear-side end position PR, respectively, and the distance between the front-side end position PF and the rear-side end position PR in the front-rear direction is referred to as a total length of the shoe sole 10.

[0036] More specifically, a first boundary plane P1 denotes an imaginary plane passing through a position of 40% of the entire length of the shoe sole 10 from the front-side end position PF and being orthogonal to the shoe center SC. Also, a second boundary plane P2 denotes an imaginary plane passing through a position of 80% of the entire length of the shoe sole 10 from the front-side end position PF and being orthogonal to the shoe center SC. In this case, the forefoot portion R1 corresponds to a portion included between the front-side end position PF and the first boundary plane P1 in the front-rear direction, the midfoot portion R2 corresponds to a portion included between the first boundary plane P1 and the second boundary plane P2 in the front-rear direction, and the rearfoot portion R3 corresponds to a portion included between the second boundary plane P2 and the rear-side end position PR in the front-rear direction.

[0037] Further, as shown in FIGS. 2 and 3, the shoe 1 is divided into a medial foot-side portion (a portion on the S1 side shown in FIGS. 2 and 3) and a lateral foot-side portion (a portion on the S2 side shown in FIGS. 2 and 3) in the left-right direction in a plan view. In this case, the medial foot-side portion corresponds to the medial side of the foot in anatomical position (i.e., the side close to the midline), and the lateral foot-side portion is opposite to the medial side of the foot in anatomical position (i.e., the side away from the midline).

[0038] As shown in FIG. 1, the upper 60 includes an upper body 61, a shoe tongue 62, and a shoelace 63. Among them, the shoe tongue 62 and the shoelace 63 are both fixed or attached to the upper body 61.

[0039] The upper body 61 has a top-side portion provided with a top-side opening through which a top part of an ankle of the wearer's foot and a part of the instep of the wearer's foot are exposed. Further, the upper body 61 has a bottom-side portion provided with, as one example, a bottom-side opening covered by the shoe sole 10 and, as another example, a bottom portion formed by stitching a lower end of the upper body 61 with French seam or the like.

[0040] The shoe tongue 62 is fixed to the upper body 61 by sewing, welding, bonding, or a combination thereof so as to cover a portion of the top-side opening provided in the upper body 61 through which a part of the instep of the wearer's foot is exposed. For the upper body 61 and the shoe tongue 62, for example, woven fabric, knitted fabric, nonwoven fabric, synthetic leather, resin, or the like may be used. For shoes particularly required to be air permeable and lightweight, a double raschel warp knitted fabric with a polyester yarn knitted therein may be used.

[0041] The shoelace 63 is formed of a member in the form of a string for pulling together, in the foot width direction of the wearer's foot, portions of a peripheral edge of the top-side opening which is provided in the upper body 61 and through which a part of the instep of the wearer's foot is exposed. The shoelace 63 is passed through a plurality of holes provided along the peripheral edge of the top-side opening. When the shoelace 63 is tightened in the state in which the wearer's foot is inserted into the upper body 61, the upper body 61 can be brought into close contact with the foot.

[0042] As shown in FIGS. 1 to 7, the shoe sole 10 includes a cushion layer 20, an upper-side plate 30, a lower-side plate 40, and an additional cushion member 24. The cushion layer 20, the upper-side plate 30, the lower-side plate 40, and the additional cushion member 24 each are located to extend in the forefoot portion R1, the midfoot portion R2, and the rearfoot portion R3. The cushion layer 20 includes a first cushion member 21, a second cushion member 22, and a third cushion member 23.

[0043] The cushion layer 20 is formed entirely in a layered shape as the first cushion member 21, the second cushion member 22, and the third cushion member 23 are arranged side by side in the front-rear direction. As the first cushion member 21, the second cushion member 22, and the third cushion member 23 compressively deform when a foot lands on the ground, the cushion layer 20 mitigates the impact applied at the time of such landing on the ground. Thus, each of the first cushion member 21, the second cushion member 22, and the third cushion member 23 constituting the cushion layer 20 is formed of a soft member with a low elastic modulus. Further, the cushion layer 20 is configured to be relatively thick in order to ensure the deformation margin.

[0044] The upper-side plate 30 serves to obtain forward propulsive force by the restoring force produced in this upper-side plate 30 due to elastic deformation of this upper-side plate 30 upon receipt of a load, for example, when a foot pushes off from the ground. Thus, the upper-side plate 30 is formed of a hard member with a high elastic modulus. Further, the upper-side plate 30 is configured to be relatively thin in order to ensure the amount of deformation.

[0045] The lower-side plate 40 is what is called a spike plate and forms the ground contact surface 10b mentioned above. A cleat 50 is attached to the lower-side plate 40. Similarly to the upper-side plate 30, the lower-side plate 40 elastically deforms upon receipt of a load, for example, when a foot pushes off from the ground. Such elastic deformation causes restoring force in the lower-side plate 40 to thereby make it possible to produce forward propulsive force. Thus, the lower-side plate 40 is formed of a hard member with a high elastic modulus. Further, the lower-side plate 40 is configured to be relatively thin in order to ensure the amount of deformation.

[0046] The additional cushion member 24, which constitutes the supporting surface 10a, mainly serves to allow a more excellent feel of contact for the bottom of the wearer's foot. Similarly to the cushion layer 20, the additional cushion member 24 also compressively deforms when a foot lands on the ground to thereby mitigate the impact applied at the time of such landing on the ground. Thus, the additional cushion member 24 is formed of a soft member with a low elastic modulus. Further, since the additional cushion member 24 mainly serves to allow a more excellent feel of contact for the wearer's foot as described above, the additional cushion member 24 is configured to be thinner than the cushion layer 20.

[0047] The cushion layer 20, the upper-side plate 30, the lower-side plate 40, and the additional cushion member 24 are stacked in the up-down direction. Specifically, the cushion layer 20 is disposed on the lower-side plate 40, the upper-side plate 30 is disposed on the cushion layer 20, and the additional cushion member 24 is disposed on the upper-side plate 30.

[0048] In other words, as shown in FIG. 7, an upper-side surface 41 of the lower-side plate 40, a lower-side wall portion 212 of the first cushion member 21 (the lower-side wall portion 212 will be described later in detail), a lower-side surface 22b of the second cushion member 22, and a lower-side surface 23b of the third cushion member 23 are superimposed on one another and bonded to each other, for example, with an adhesive or the like, so that the cushion layer 20 is fixed onto the lower-side plate 40. Also, an upper-side wall portion 211 of the first cushion member 21 (the upper-side wall portion 211 will be described later in detail), an upper-side surface 22a of the second cushion member 22, an upper-side surface 23a of the third cushion member 23, and the lower-side surface 32 of the upper-side plate 30 are superimposed on one another and bonded to each other, for example, with an adhesive or the like, so that the upper-side plate 30 is fixed onto the cushion layer 20. Further, an upper-side surface 31 of the upper-side plate 30 and a lower-side surface 24b of the additional cushion member 24 are superimposed on one another and bonded to each other, for example, with an adhesive or the like, so that the additional cushion member 24 is fixed onto the upper-side plate 30. Thereby, the cushion layer 20, the upper-side plate 30, the lower-side plate 40, and the additional cushion member 24 are stacked in the order of the lower-side plate 40, the cushion layer 20, the upper-side plate 30, and the additional cushion member 24 from below in the up-down direction.

[0049] With such a configuration, the most part (the part excluding a front end portion in the front-rear direction) of the supporting surface 10a of the shoe sole 10 is formed of an upper-side surface 24a of the additional cushion member 24 while the remaining part (the front end portion in the front-rear direction) thereof is formed of a part of an upper-side surface 23a of the third cushion member 23. Further, with such a configuration, the ground contact surface 10b of the shoe sole 10 is formed of a lower-side surface 42 of the lower-side plate 40.

[0050] As shown in FIGS. 2 to 6, the first cushion member 21 is located to extend in the forefoot portion R1 and the midfoot portion R2. More specifically, the first cushion member 21 is located to extend from a substantially central portion of the forefoot portion R1 in the front-rear direction to a substantially central portion of the midfoot portion R2 in the front-rear direction, and both ends of the first cushion member 21 in the left-right direction reach a medial foot-side side surface and a lateral foot-side side surface of the shoe sole 10. Thereby, as shown in FIG. 2, the first cushion member 21 is disposed to partially include a portion of the shoe sole 10 that supports the MP joint of the wearer's foot (FIG. 2 shows an imaginary line 100 indicating a portion in which the MP joint of the wearer's foot is located when the wearer wears the shoe).

[0051] In this case, referring particularly to FIG. 7, the first cushion member 21 is formed of a three-dimensional structure provided with a plurality of recesses and a plurality of protrusions, unlike the second cushion member 22, the third cushion member 23, and the additional cushion member 24, each of which will be described later in detail.

[0052] FIG. 8A is a perspective view of a cushion member having basically the same structure as that of the first cushion member included in the shoe sole according to the present embodiment. FIG. 8B is a perspective view of a unit structure body of the cushion member. Before describing the detailed structure, material, and the like of the first cushion member 21, the following describes a cushion member 21A having basically the same structure as that of the first cushion member 21 with reference to FIGS. 8A and 8B.

[0053] As shown in FIG. 8A, the cushion member 21A includes a three-dimensional structure S having a plurality of unit structure bodies U. Each of the plurality of unit structure bodies U has a three-dimensional shape formed by a wall W having an outer shape defined by a pair of parallel flat surfaces (see FIG. 8B). Thereby, the three-dimensional structure S also has a three-dimensional shape formed by the wall W having an outer shape defined by a pair of parallel flat surfaces.

[0054] The unit structure body U has a structure obtained by adding a thickness to a base structure unit having a geometrical surface structure. More specifically, the unit structure body U is formed by adding a thickness to each of divided structure units obtained by dividing a structure unit into two structure units in one of its orthogonal three-axis directions, the structure unit being formed of a plurality of flat surfaces disposed to intersect with each other so as to be hollow inside.

[0055] In this case, in the unit structure body U shown in FIG. 8B, the above-mentioned surface structure is a Kelvin structure, and the unit structure body U is formed by adding a thickness to each of divided structure units obtained by dividing a structure unit having a Kelvin structure into two structure units in a height direction (in a Z-axis direction shown in the figure) of the orthogonal three-axis directions.

[0056] More specifically, the unit structure body U includes: one upper-side wall portion 211; four divided lower-side wall portions 212a; and four upright wall portions 213 each connecting the upper-side wall portion 211 and a corresponding one of the lower-side wall portions 212a. Each of the upright wall portions 213 extends to intersect with the upper-side wall portion 211 and a corresponding one of the lower-side wall portions 212a, and is connected at each of its side ends to the adjacent upright wall portion 213. Thus, the four upright wall portions 213 entirely form an annular shape. Note that each of the upper-side wall portion 211, the lower-side wall portions 212a, and the upright wall portions 213 has a flat plate shape.

[0057] Each of the four divided lower-side wall portions 212a included in one unit structure body U is contiguous to, and thereby integrated with, one of the lower-side wall portions 212a included in another unit structure body U adjacent to this one unit structure body U. Thus, in the three-dimensional structure S, each of the lower-side wall portions 212a included in each of the four unit structure bodies U adjacent to each other is contiguous to an adjacent lower-side wall portion 212a included in an adjacent one of these four unit structure bodies U, to thereby form one lower-side wall portion 212 substantially similar in shape to the above-mentioned one upper-side wall portion 211.

[0058] The cushion member 21A is intended to exhibit a shock absorbing function in the above-mentioned height direction. Thus, as shown in FIG. 8A, the plurality of unit structure bodies U are repeatedly arranged in a regular and continuous manner in each of a width direction (an X-axis direction shown in the figure) and a depth direction (a Y-axis direction shown in the figure) of the orthogonal three-axis directions. Thereby, the three-dimensional structure S has a structure in which upwardly protruding portions and downwardly protruding portions are alternately arranged in a plan view. FIG. 8A shows only three unit structure bodies U arranged adjacent to each other in the width direction and the depth direction.

[0059] The material of the cushion member 21A may be basically any material as long as it has appropriate elastic force, but is preferably a resin material or a rubber material. More specifically, when the cushion member 21A is made of resin, for example, the material of the cushion member 21A may be a polyolefin resin, an ethylene-vinyl acetate copolymer (EVA), a polyamide-based thermoplastic elastomer (TPA, TPAE), thermoplastic polyurethane (TPU), and a polyester-based thermoplastic elastomer (TPEE). On the other hand, when the cushion member 21A is made of rubber, for example, butadiene rubber may be used.

[0060] The cushion member 21A can also be formed of a polymer composition. In that case, examples of polymer to be contained in the polymer composition includes olefinic polymers such as olefinic elastomers and olefinic resins. Examples of the olefinic polymers include polyolefins such as polyethylene (e.g., linear low density polyethylene (LLDPE), high density polyethylene (HDPE), and the like), polypropylene, ethylene-propylene copolymer, propylene-1-hexene copolymer, propylene-4-methyl-1-pentene copolymer, propylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-4-methyl-pentene copolymer, ethylene-1-butene copolymer, 1-butene-1-hexene copolymer, 1-butene-4-methyl-pentene, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate 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), propylene-vinyl acetate copolymer, and the like.

[0061] The polymer may be an amide-based polymer such as an amide-based elastomer and an amide-based resin. Examples of the amide-based polymer include polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 610, and the like.

[0062] The polymer may be an ester-based polymer such as an ester-based elastomer and an ester-based resin. Examples of the ester-based polymer include polyethylene terephthalate, polybutylene terephthalate, and the like.

[0063] The polymer may be a urethane-based polymer such as a urethane-based elastomer and a urethane-based resin. Examples of the urethane-based polymer include polyester-based polyurethane, polyether-based polyurethane, and the like.

[0064] The polymer may be a styrene-based polymer such as a styrene-based elastomer and a styrene-based resin. Examples of the styrene-based elastomer include styrene-ethylene-butylene copolymer (SEB), styrene-butadiene-styrene copolymer (SBS), a hydrogenated product of SBS (styrene-ethylene-butylene-styrene copolymer (SEBS)), styrene-isoprene-styrene copolymer (SIS), a hydrogenated product of SIS (styrene-ethylene-propylene-styrene copolymer (SEPS)), styrene-isobutylene-styrene copolymer (SIBS), styrene-butadiene-styrene-butadiene (SBSB), styrene-butadiene-styrene-butadiene-styrene (SBSBS), and the like. Examples of the styrene-based resin include polystyrene, acrylonitrile styrene resin (AS), acrylonitrile butadiene styrene resin (ABS), and the like.

[0065] Examples of the polymer may include acrylic polymers such as polymethylmethacrylate, urethane-based acrylic polymers, polyester-based acrylic polymers, polyether-based acrylic polymers, polycarbonate-based acrylic polymers, epoxy-based acrylic polymers, conjugated diene polymer-based acrylic polymers and hydrogenated products thereof, urethane-based methacrylic polymers, polyester-based methacrylic polymers, polyether-based methacrylic polymers, polycarbonate-based methacrylic polymers, epoxy-based methacrylic polymers, conjugated diene polymer-based methacrylic polymers and hydrogenated products thereof, polyvinyl chloride-based resins, silicone-based elastomers, butadiene rubber (BR), isoprene rubber (IR), chloroprene rubber (CR), natural rubber (NR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butyl rubber (IIR), and the like.

[0066] The method of manufacturing the cushion member 21A is not particularly limited. The cushion member 21A can be manufactured, for example, by molding such as injection molding using a mold, cast molding, sheet molding; additive manufacturing using a three-dimensional additive manufacturing apparatus; or the like. In particular, the cushion member 21A has a relatively simple shape, and therefore, can be manufactured easily by molding using a mold. This eliminates the need to perform additive manufacturing using a three-dimensional additive manufacturing apparatus or perform molding using a complicated mold, so that the manufacturing cost can be significantly reduced.

[0067] In the cushion member 21A configured as described above, compressive deformation occurs when a load is applied in the height direction (in the Z-axis direction shown in the figure). At this time, due to the structure of the cushion member 21A, buckling occurs in the upright wall portion 213. Further, when the above-mentioned application of the load is stopped, the buckling in the upright wall portion 213 is also eliminated, and the cushion member 21A returns to its original shape.

[0068] As shown in FIGS. 1 to 6, the first cushion member 21 included in the shoe sole 10 according to the present embodiment has the same configuration as that of the above-mentioned cushion member 21A except that the shape, thickness, and the like of the unit structure body U are slightly deformed or changed in each part while maintaining the basic structure of the cushion member 21A so as to allow the first cushion member 21 to be provided in the shoe sole 10.

[0069] Thus, the unit structure body of the first cushion member 21 included in the shoe sole 10 according to the present embodiment is also formed by adding a thickness to each of divided structure units obtained by dividing a structure unit having a Kelvin structure into two structure units in the height direction (in the Z-axis direction shown in the figure) of the orthogonal three-axis directions. Thereby, the first cushion member 21 is formed of a three-dimensional structure in which a plurality of the unit structure bodies are repeatedly arranged to be adjacent to each other.

[0070] With such a configuration, in the shoe sole 10 according to the present embodiment, buckling occurs in the first cushion member 21 when a foot lands on the ground. Thereby, the portion of the cushion layer 20 that supports the MP joint of the wearer's foot is to have not only high shock absorbing performance but also high resilience performance. In other words, the first cushion member 21 has the above-described structural characteristics, and thereby, exhibits high shock absorbing performance while still having compression rigidity higher than that of the second cushion member 22 described later.

[0071] In this case, the first cushion member 21 has the unit structure body U formed by adding a thickness to each of divided structure units obtained by dividing a structure unit having a Kelvin structure into two structure units in the height direction. In place of the structure unit having a Kelvin structure, a structure unit having another surface structure may be used. For example, in the case of a cushion member having a three-dimensional shape formed by a wall having an outer shape defined by a pair of parallel flat surfaces similarly to the above-mentioned first cushion member 21, other structure units such as an octet structure, a cubic structure, and a cubic-octet structure can be used in addition to the Kelvin structure.

[0072] Each of the structure units having the surface structures as described above is a structure unit formed of a plurality of flat surfaces disposed to intersect with each other so as to be hollow inside. This structure unit is divided into two structure units in one of the orthogonal three-axis directions, and a thickness is added to each of the divided structure units to thereby form a cushion member. Thereby, the cushion member capable of achieving not only high shock absorbing performance but also high resilience performance can be obtained.

[0073] FIG. 9A is a perspective view of a cushion member similar in structure to the first cushion member included in the shoe sole according to the present embodiment. FIG. 9B is a perspective view of a unit structure body of the cushion member. In this case, in the shoe sole 10 according to the present embodiment, a cushion member 21B as shown in FIG. 9A may be provided as the first cushion member in place of the first cushion member 21 described above. The following describes the cushion member 21B similar in structure to the first cushion member 21 included in the shoe sole according to the present embodiment with reference to FIGS. 9A and 9B.

[0074] The cushion member 21B shown in FIG. 9A has, as its unit structure body U, a structure obtained by adding a thickness to a base structure unit having a geometrical surface structure. More specifically, the unit structure body U is formed by adding a thickness to each of divided structure units obtained by dividing a structure unit having a mathematically defined triply periodic minimal surface into two structure units in one of its orthogonal three-axis directions. Note that a minimal surface is defined as a curved surface that is minimal in area among the curved surfaces each having a given closed curve as a boundary.

[0075] In this case, in the unit structure body U shown in FIG. 9B, the above-mentioned surface structure is a Schwartz P structure, and the unit structure body U is formed by adding a thickness to each of divided structure units obtained by dividing a structure unit having a Schwartz P structure into two structure units in the height direction (in the Z-axis direction shown in the figure) of the orthogonal three-axis directions.

[0076] Similarly to the above-mentioned cushion member 21A, the cushion member 21B configured as described above also compressively deforms when a load is applied thereto in the height direction (in the Z-axis direction shown in the figure). At this time, due to the structure of the cushion member 21B, buckling occurs in the upright wall portion 213. Further, when the above-mentioned application of the load is stopped, the buckling in the upright wall portion 213 is also eliminated, and the cushion member 21B returns to its original shape.

[0077] Therefore, also in the case where a cushion member having basically the same structure as that of the cushion member 21B is used as the first cushion member 21 included in the shoe sole 10 according to the present embodiment in place of the cushion member 21A, buckling occurs in the first cushion member 21 when a foot lands on the ground. Thereby, the portion of the cushion layer 20 that supports the MP joint of the wearer's foot is to have not only high shock absorbing performance but also high resilience performance.

[0078] Further, in place of the above-mentioned structure unit having a Schwartz P structure, a structure unit having other triply periodic minimal surfaces may be used. Examples applicable as a structure unit having other triply periodic minimal surfaces may be a gyroid structure, a Schwartz D structure, and the like. By configuring a shock absorbing member by adding a thickness to each of divided structure units obtained by dividing the above-mentioned structure unit into two structure units in one of the orthogonal three-axis directions, a cushion member capable of achieving not only high shock absorbing performance but also high resilience performance can be obtained.

[0079] As shown in FIGS. 2 to 7, the second cushion member 22 is formed of a flat block-shaped member and is located to extend in the midfoot portion R2 and the rearfoot portion R3. More specifically, the second cushion member 22 is located to extend from the substantially central portion of the midfoot portion R2 in the front-rear direction to the rear end portion of the rearfoot portion R3 in the front-rear direction, and both ends of the second cushion member 22 in the left-right direction reach the medial foot-side side surface and the lateral foot-side side surface of the shoe sole 10.

[0080] The second cushion member 22 is preferably excellent in shock absorbing performance while having appropriate strength and is also lower in compression rigidity than the first cushion member 21. From this point of view, the second cushion member 22 can be formed, for example, of a member made of resin or rubber and is suitably formed of a foam material made of resin or rubber. By way of example, the second cushion member 22 can be formed of a foam material or a non-foam material such as a polyolefin resin, an ethylene-vinyl acetate copolymer (EVA), a polyamide-based thermoplastic elastomer (TPA, TPAE), thermoplastic polyurethane (TPU), and a polyester-based thermoplastic elastomer (TPEE).

[0081] As shown in FIGS. 2 to 7, the third cushion member 23 is formed of a flat block-shaped member and located at a front end portion of the forefoot portion R1 in the front-rear direction. Both ends of the third cushion member 23 in the left-right direction reach the medial foot-side side surface and the lateral foot-side side surface of the shoe sole 10.

[0082] The third cushion member 23 is preferably excellent in shock absorbing performance while having appropriate strength and is preferably lower in compression rigidity than the first cushion member 21. From this point of view, similarly to the second cushion member 22, the third cushion member 23 can be formed, for example, of a member made of resin or rubber and is suitably formed of a foam material made of resin or rubber. By way of example, the third cushion member 23 can be formed of a foam material or a non-foam material such as a polyolefin resin, an ethylene-vinyl acetate copolymer (EVA), a polyamide-based thermoplastic elastomer (TPA, TPAE), thermoplastic polyurethane (TPU), a polyester-based thermoplastic elastomer (TPEE), and the like. The third cushion member 23 may be formed of the same material as that of the second cushion member 22 or may be formed of a material different from that of the second cushion member 22.

[0083] As shown in FIGS. 2 to 7, the upper-side plate 30 is made of a member formed to be sufficiently thin in thickness and is located to extend in the forefoot portion R1, the midfoot portion R2, and the rearfoot portion R3. More specifically, the upper-side plate 30 is located to extend from a portion close to the front end of the forefoot portion R1 in the front-rear direction to a substantially central portion of the rearfoot portion R3 in the front-rear direction, and both ends of the upper-side plate 30 in the left-right direction reach the medial foot-side side surface and the lateral foot-side side surface of the shoe sole 10.

[0084] The upper-side plate 30 should only be made of a material harder than the material of the cushion layer 20 and the material thereof is not particularly limited. Examples of the material of the upper-side plate 30 include: a fiber-reinforced resin made using, as reinforcing fibers, carbon fibers, glass fibers, aramid fibers, DYNEEMA fibers, ZYLON fibers, boron fibers, or the like and using, as base materials, an epoxy resin, a polyester resin, a phenol resin, a polyamide resin, a polypropylene resin, a polyethylene resin, a polyurethane resin, or the like; a non-fiber-reinforced resin made of a polymer resin such as a urethane-based thermoplastic elastomer (TPU), an amide-based thermoplastic elastomer (TPA), or an ethylene-vinyl acetate copolymer (EVA); and the like.

[0085] As shown in FIGS. 2 to 7, the additional cushion member 24 is made of a member formed to be sufficiently thin in thickness and is located to extend in the forefoot portion R1, the midfoot portion R2, and the rearfoot portion R3. More specifically, similarly to the upper-side plate 30, the additional cushion member 24 is located to extend from a portion close to the front end of the forefoot portion R1 in the front-rear direction to a substantially central portion of the rearfoot portion R3 in the front-rear direction, and both ends of the additional cushion member 24 in the left-right direction reach the medial foot-side side surface and the lateral foot-side side surface of the shoe sole 10.

[0086] The additional cushion member 24 is preferably excellent in shock absorbing performance while having appropriate strength and is preferably lower in compression rigidity than the first cushion member 21. From this point of view, similarly to the second cushion member 22 and the third cushion member 23, the additional cushion member 24 can be formed, for example, of a member made of resin or rubber and is suitably formed of a foam material made of resin or rubber. By way of example, the additional cushion member 24 may be formed of a foam material or a non-foam material such as a polyolefin resin, an ethylene-vinyl acetate copolymer (EVA), a polyamide-based thermoplastic elastomer (TPA, TPAE), thermoplastic polyurethane (TPU), a polyester-based thermoplastic elastomer (TPEE), and the like. The additional cushion member 24 may be formed of the same material as that of the second cushion member 22 and/or the third cushion member 23, or may be formed of a material different from that of the second cushion member and/or the third cushion member 23.

[0087] As shown in FIGS. 2 to 7, the lower-side plate 40 is made of a member formed to be sufficiently thin in thickness, and is located to extend in the forefoot portion R1, the midfoot portion R2, and the rearfoot portion R3. More specifically, the lower-side plate 40 is located to extend from the front end portion of the forefoot portion R1 in the front-rear direction to a portion close to the rear end of the rearfoot portion R3 in the front-rear direction, and both ends of the lower-side plate 40 in the left-right direction reach the medial foot-side side surface and the lateral foot-side side surface of the shoe sole 10.

[0088] The lower-side plate 40, which is a spike plate as described above, is provided with a plurality of base portions 43 for retaining the cleats 50 (see FIG. 1), the plurality of base portions 43 being provided in portions included in the forefoot portion R1 and the midfoot portion R2 of the lower-side plate 40. Each of the plurality of base portions 43 is formed, for example, by embedding a nut-like component made of metal in the lower-side plate 40. Thereby, a plurality of retaining holes 43a for attaching the cleats 50 are located to be exposed on the lower-side surface 42 (i.e., the ground contact surface 10b) of the lower-side plate 40. Each cleat 50 protrudes in a pin shape from the ground contact surface 10b of the shoe sole 10 to thereby increase the propulsive force occurring when a foot pushes off from the ground.

[0089] A plurality of protrusions 44 are provided at prescribed positions in portions that are included in the forefoot portion R1 and the midfoot portion R2 on the lower-side surface 42 of the lower-side plate 40 and that are not provided with the plurality of base portions 43. Similarly to the plurality of cleats 50 mentioned above, the plurality of protrusions 44 protrude from the ground contact surface 10b of the shoe sole 10 to thereby increase the propulsive force occurring when a foot pushes off from the ground.

[0090] Further, an uneven portion 45 including protrusions and recesses is provided in each of the rear end portion of the midfoot portion R2 and the rearfoot portion R3 on the lower-side surface 42 of the lower-side plate 40. The uneven portion 45 enhances the grip performance exhibited when a foot lands on the ground.

[0091] In addition, a first rib 46 and a second rib 47 are provided on the medial foot-side end portion and the lateral foot-side end portion, respectively, in the midfoot portion R2 on the lower-side surface 42 of the lower-side plate 40. The first rib 46 and the second rib 47 are formed by forming the lower-side plate 40 to be locally thicker than other portions. In this case, the first rib 46 extends along a medial foot-side edge portion of the shoe sole 10, and the second rib 47 extends along a lateral foot-side edge portion of the shoe sole 10. The first rib 46 and the second rib 47 serve to locally increase the rigidity of the shoe sole 10, and their functions will be described later.

[0092] The lower-side plate 40 should only be made of a material harder than the material of the cushion layer 20, but the material thereof is not particularly limited. Examples of the material of the lower-side plate 40 include: a fiber-reinforced resin made using, as reinforcing fibers, carbon fibers, glass fibers, aramid fibers, DYNEEMA fibers, ZYLON fibers, boron fibers, or the like and using, as base materials, an epoxy resin, a polyester resin, a phenol resin, a polyamide resin, a polypropylene resin, a polyethylene resin, a polyurethane resin, or the like; a non-fiber-reinforced resin made of a polymer resin such as a urethane-based thermoplastic elastomer (TPU), an amide-based thermoplastic elastomer (TPA), or an ethylene-vinyl acetate copolymer (EVA); and the like.

[0093] FIGS. 10 and 11 are a perspective view and a plan view, respectively, showing the state of the shoe sole according to the present embodiment from which the additional cushion member and the upper-side plate have been removed. FIG. 12 is a schematic cross-sectional view of the shoe sole according to the present embodiment taken along a line XII-XII shown in FIG. 3. Further, FIGS. 13A, 13B, and 13C are schematic cross-sectional views of the shoe sole according to the present embodiment taken along lines XIIIA-XIIIA, XIIIB-XIIIB, and XIIIC-XIIIC, respectively, shown in FIG. 3. FIG. 14 is a schematic plan view showing the compression rigidity in each part of the cushion layer included in the shoe sole. Referring to FIGS. 10 to 14, the following describes a more detailed structure of the shoe sole 10 according to the present embodiment and the compression rigidity in each part of the cushion layer 20 included in the shoe sole 10.

[0094] As described above, in the shoe sole 10 according to the present embodiment, the cushion layer 20, the upper-side plate 30, the lower-side plate 40, and the additional cushion member 24 are stacked in the order of the lower-side plate 40, the cushion layer 20, the upper-side plate 30, and the additional cushion member 24 from below in the up-down direction. In other words, the upper-side plate 30 is located on the supporting surface 10a side so as to cover the upper-side surface of the cushion layer 20, and the lower-side plate 40 is located on the ground contact surface 10b side so as to cover the lower-side surface of the cushion layer 20.

[0095] Thereby, the upper-side plate 30 and the lower-side plate 40 are disposed to face each other in the up-down direction. By the upper-side plate 30 and the lower-side plate 40, the first cushion member 21, the second cushion member 22, and the third cushion member 23 that constitute the cushion layer 20 are sandwiched between the upper-side plate 30 and the lower-side plate 40 except for the front end portion of the third cushion member 23.

[0096] As shown in FIGS. 10 to 12 and FIGS. 13A to 13C, the first cushion member 21 is located to extend from the substantially central portion of the forefoot portion R1 in the front-rear direction to the substantially central portion of the midfoot portion R2 in the front-rear direction, the second cushion member 22 is located to extend from the substantially central portion of the midfoot portion R2 in the front-rear direction to the rear end portion of the rearfoot portion R3 in the front-rear direction, and the third cushion member 23 is located at the front end portion of the forefoot portion R1 in the front-rear direction. In other words, the first cushion member 21, the second cushion member 22, and the third cushion member 23 are arranged side by side in the order of the third cushion member 23, the first cushion member 21, and the second cushion member 22 from the front side in the front-rear direction.

[0097] In this case, as shown particularly in FIGS. 10 and 11, the second cushion member 22 has a substantially Y-shape in a plan view including a base end portion 22A, a medial foot-side branch portion 22B, and a lateral foot-side branch portion 22C. The base end portion 22A is located to extend from the substantially central portion of the midfoot portion R2 in the front-rear direction to the rear end portion of the rearfoot portion R3, the medial foot-side branch portion 22B is located to protrude forward from the medial foot-side portion at the front end of the base end portion 22A, and the lateral foot-side branch portion 22C is located to protrude forward from the lateral foot-side portion at the front end of the base end portion 22A. Thereby, the medial foot-side branch portion 22B is located at the medial foot-side end portion in the substantially central portion of the midfoot portion R2 in the front-rear direction, and the lateral foot-side branch portion 22C is located at the lateral foot-side end portion in the substantially central portion of the midfoot portion R2 in the front-rear direction.

[0098] In other words, the second cushion member 22 has a shape bifurcating forward in the front-rear direction, the shape including: the medial foot-side branch portion 22B extending to the medial foot-side end portion on the front side with respect to the rearfoot portion R3 in the front-rear direction; and the lateral foot-side branch portion 22C extending to the lateral foot-side end portion on the front side with respect to the rearfoot portion R3 in the front-rear direction. The base end portion 22A extends from the substantially central portion of the midfoot portion R2 in the front-rear direction to the rear end portion of the rearfoot portion R3 in the front-rear direction. Thus, the second cushion member 22 has a gap portion G between the medial foot-side branch portion 22B and the lateral foot-side branch portion 22C. This gap portion G is located in the substantially central portion of the midfoot portion R2 in the front-rear direction.

[0099] In this case, the rear edge of the first cushion member 21 in the front-rear direction extends substantially in the left-right direction, the rear edge of the first cushion member 21 being adjacent to a front edge of the second cushion member 22 in the front-rear direction where the medial foot-side branch portion 22B, the lateral foot-side branch portion 22C, and the gap portion G are provided. Thus, the above-mentioned gap portion G where no cushion member is provided is located in a portion of the cushion layer 20 that corresponds to the substantially central portion of the midfoot portion R2 in the front-rear direction.

[0100] In the shoe sole 10 according to the present embodiment configured as described above, as shown in FIG. 14, the cushion layer 20 includes: a first region A1 that supports the MP joint of the wearer's foot; and a second region A2 included in a portion on the rear side with respect to the first region A1 in the front-rear direction and on the front side with respect to the rearfoot portion R3 in the front-rear direction. The second region A2 includes: a third region A3 located in a central portion in the left-right direction corresponding to the foot width direction of the wearer's foot; a fourth region A4 located in the medial foot-side end portion in the left-right direction; and a fifth region A5 located in the lateral foot-side end portion in the left-right direction.

[0101] In addition, in the shoe sole 10 according to the present embodiment, the first region A1 is formed of a part of the first cushion member 21 higher in compression rigidity than the second cushion member 22, the fourth region A4 of the second region is formed of the medial foot-side branch portion 22B provided in the second cushion member 22 lower in compression rigidity than the first cushion member 21, and the fifth region A5 of the second region is formed of the lateral foot-side branch portion 22C provided in the second cushion member 22 lower in compression rigidity than the first cushion member 21. Further, the third region A3 of the second region is formed of the gap portion G provided between the medial foot-side branch portion 22B and the lateral foot-side branch portion 22C in the second cushion member 22.

[0102] Thus, in the shoe sole 10 according to the present embodiment, the fourth region A4 and the fifth region A5 each are configured to be lower in compression rigidity than the first region A1, and the third region A3 is configured to be lower in compression rigidity than the fourth region A4 and the fifth region A5.

[0103] With such a configuration, the shoe sole 10 according to the present embodiment can achieve the following effects.

[0104] First, a portion of the cushion layer 20 that supports the MP joint of the wearer's foot, i.e., the first region A1, is formed of the first cushion member 21 higher in compression rigidity than the second cushion member 22 while still exhibiting high shock absorbing performance as described above. Thereby, when a foot pushes off from the ground, not only the resilient force occurring when the upper-side plate 30 and the lower-side plate 40 return to their original shapes can be achieved, but also the resilient force occurring when the buckling of the first cushion member 21 is eliminated can be achieved, without preventing deformation of the upper-side plate 30 and the lower-side plate 40 at the time when the foot lands on the ground. Thereby, a shoe sole increased in forward propulsive force can be obtained. In this case, the above-mentioned portion supporting the MP joint of the wearer's foot, i.e., the first region A1, is a portion where the highest foot pressure is applied to the shoe sole 10 when a foot pushes off from the ground. Thus, the configuration as described above makes it possible to maximize the resilient force occurring in the upper-side plate 30, the lower-side plate 40, and the first cushion member 21.

[0105] Secondly, the second cushion member lower in compression rigidity than the first cushion member 21 is disposed in the portion of the cushion layer 20 that is adjacent to the rear edge of the first cushion member 21 in the front-rear direction. Thereby, when a foot lands on the ground, it becomes difficult to prevent not only the deformation of the upper-side plate 30 and the lower-side plate 40 in the portion including the first cushion member 21 but also the deformation of the first cushion member 21 itself. Thus, the above-described resilient force can be more reliably obtained, so that a shoe sole increased in forward propulsive force can be obtained.

[0106] Thirdly, a shoe sole that can be suppressed from twisting and improved in stability of a foot landing on the ground can be provided. In other words, in the configuration in which the upper-side plate 30 and the lower-side plate 40 are disposed to face each other, the cushion layer 20 located therebetween is prevented from deforming in each part by a different amount according to the pressure of the foot landing on the ground. Accordingly, the cushion layer 20 deforms entirely more uniformly, which causes a concern that the stability of the foot landing on the ground may be significantly impaired. By the configuration as described above, however, in a portion between the first region A1 that supports the MP joint of the wearer's foot and the rearfoot portion R3, the second region A2 is provided in which the compression rigidity is lower in the central portion (corresponding to the third region A3) in the left-right direction and higher in the medial foot-side end portion (corresponding to the fourth region A4) and the lateral foot-side end portion (corresponding to the fifth region A5) in the left-right direction. Thereby, twisting of the shoe sole 10 can be suppressed while the stability of the foot landing on the ground is increased. Thus, the wearer's foot can be prevented from collapsing toward the medial foot side or the lateral foot side.

[0107] Therefore, the shoe sole 10 according to the present embodiment and the shoe 1 including the same make it possible to improve the stability of a foot landing on the ground without impairing the forward propulsive force occurring when the foot pushed off from the ground, while adopting the configuration in which the upper-side plate 30 and the lower-side plate 40 are disposed to face each other with the cushion layer 20 being interposed therebetween.

[0108] In addition, in the shoe sole 10 according to the present embodiment and the shoe 1 including the same, the first rib 46 and the second rib 47 are provided on the medial foot-side end portion and the lateral foot-side end portion, respectively, of the midfoot portion R2 on the lower-side surface 42 (i.e., the ground contact surface 10b) of the lower-side plate 40, as described above. With such a configuration, the rigidity becomes higher in the medial foot-side portion and the lateral foot-side portion of the lower-side plate 40 than in the central portion of the lower-side plate 40 in the left-right direction. Thereby, twisting of the shoe sole 10 can be suppressed, so that the stability of a foot landing on the ground is also increased in this aspect. As shown in FIG. 11, the first rib 46 and the second rib 47 are preferably provided to overlap with the fourth region A4 and the fifth region A5, respectively. Such a configuration makes it possible to further enhance the effect of suppressing the twist.

[0109] Further, in the shoe sole 10 according to the present embodiment and the shoe 1 including the same, as shown in FIG. 13A, a portion included in the forefoot portion R1 of the upper-side plate 30 has a curved shape such that its central portion in the left-right direction bulges downward in the up-down direction with respect to the medial foot-side end portion and the lateral foot-side end portion. Such a configuration makes it possible to increase the amount of deformation of the upper-side plate 30 at the time when a foot lands on the ground. Thus, larger resilient force can be obtained as the upper-side plate 30 returns to its original shape when the foot pushes off from the ground. Therefore, the forward propulsive force occurring when the foot pushes off from the ground can be increased.

[0110] In addition, in the shoe sole 10 according to the present embodiment and the shoe 1 including the same, as shown in FIG. 13A, a portion included in the forefoot portion R1 of the lower-side plate 40 has a curved shape such that its central portion in the left-right direction bulges downward in the up-down direction with respect to the medial foot-side end portion and the lateral foot-side end portion, similarly to the upper-side plate 30. Such a configuration makes it possible to increase the amount of deformation of the above-mentioned portion in the lower-side plate 40 at the time when a foot lands on the ground, so that larger resilient force can be obtained as the lower-side plate 40 returns to its original shape when the foot pushes off from the ground. Therefore, the forward propulsive force occurring when the foot pushes off from the ground can be further increased.

[0111] In addition, as a degree at which the portions included in the forefoot portion R1 of the upper-side plate 30 and the lower-side plate 40 are curved with respect to the left-right direction, the radius of curvature of each curve is preferably 150 mm or more and 400 mm or less. This is because each radius of curvature smaller than 150 mm may prevent sufficient resilient force from being obtained, and each radius of curvature larger than 400 mm may impair the stability of a foot landing on the ground.

[0112] In this case, as described above, in the shoe sole 10 according to the present embodiment and the shoe 1 including the same, the first rib 46 and the second rib 47 are provided on the medial foot-side end portion and the lateral foot-side end portion, respectively, in the portions included in the midfoot portion R2 of the lower-side plate 40. In such a configuration, the portions curved with respect to the left-right direction that are located in the forefoot portion R1 of the upper-side plate 30 and the lower-side plate 40 are not prevented by the first rib 46 and the second rib 47 from deforming when a foot lands on the ground. In other words, when the portion included in the midfoot portion R2 of the lower-side plate 40 is increased in entire thickness to thereby increase the rigidity of this portion in order to suppress twisting, such increased rigidity may prevent the deformation of the portions located in the forefoot portion R1 of the upper-side plate 30 and the lower-side plate 40. However, such a problem can be avoided by locally increasing the rigidity of only the medial foot-side end portion and the lateral foot-side end portion in the portion included in the midfoot portion R2 of the lower-side plate 40, as described above.

[0113] Further, in the shoe sole 10 according to the present embodiment and the shoe 1 including the same, the forefoot portion R1 is configured such that the distance between the upper-side plate 30 and the lower-side plate 40 gradually decreases toward the front side in the front-rear direction, as shown in FIG. 12. In other words, in the forefoot portion R1, the cushion layer 20 is configured to be gradually thinner toward the front side in the front-rear direction. Such a configuration makes it possible to more smoothly shift the body weight toward the front side when a foot lands on the ground, so that forward propulsive force can be further increased.

Summary of Disclosure in Embodiments

[0114] The following summarizes the characteristic configurations of the shoe sole according to the above-described embodiment and the shoe including the same.

[Supplementary Note 1]

[0115] A shoe sole including: a forefoot portion configured to support a toe portion and a ball portion of a foot of a wearer; a midfoot portion configured to support an arch portion of the foot of the wearer; and a rearfoot portion configured to support a heel portion of the foot of the wearer, the forefoot portion, the midfoot portion, and the rearfoot portion being connected in a front-rear direction corresponding to a foot length direction of the foot of the wearer, the shoe sole having: an upper-side surface configured as a supporting surface for supporting a bottom of the foot of the wearer; and a lower-side surface configured as a ground contact surface, the shoe sole including: [0116] a cushion layer located to extend in the forefoot portion, the midfoot portion, and the rearfoot portion; [0117] an upper-side plate located close to the supporting surface with respect to the cushion layer to cover an upper-side surface of the cushion layer, the upper-side plate being located to extend in at least the forefoot portion and the midfoot portion; and [0118] a lower-side plate located close to the ground contact surface with respect to the cushion layer to cover a lower-side surface of the cushion layer, the lower-side plate being located to extend in at least the forefoot portion and the midfoot portion, wherein [0119] the cushion layer includes [0120] a first region configured to support a metatarsophalangeal (MP) joint of the foot of the wearer, and [0121] a second region included in a portion located on a rear side with respect to the first region in the front-rear direction and located on a front side with respect to the rearfoot portion in the front-rear direction, [0122] the second region includes [0123] a third region located in a central portion in a left-right direction corresponding to a foot width direction of the foot of the wearer, [0124] a fourth region located in a medial foot-side end portion in the left-right direction, and [0125] a fifth region located in a lateral foot-side end portion in the left-right direction, [0126] the fourth region and the fifth region are lower in compression rigidity than the first region, and [0127] the third region is lower in compression rigidity than the fourth region and the fifth region.

[0128] The configuration described in the above Supplementary Note 1 makes it possible to provide a shoe sole that can be significantly improved in stability of a foot landing on the ground without impairing the forward propulsive force occurring when the foot pushes off from the ground, while adopting a configuration in which the upper-side plate and the lower-side plate are disposed to face each other with the cushion layer being interposed therebetween.

[Supplementary Note 2]

[0129] The shoe sole according to Supplementary Note 1, wherein [0130] the cushion layer includes [0131] a first cushion member disposed at least in a portion of the cushion layer to form the first region, the portion of the cushion layer being configured to support the MP joint of the foot of the wearer, and [0132] a second cushion member disposed to at least extend in a portion included in the midfoot portion of the cushion layer and a portion included in the rearfoot portion of the cushion layer to form the second region, [0133] the second cushion member has a shape bifurcating forward in the front-rear direction, the shape including [0134] a medial foot-side branch portion extending to a medial foot-side end portion on the front side with respect to the rearfoot portion in the front-rear direction, and [0135] a lateral foot-side branch portion extending to the lateral foot-side end portion on the front side with respect to the rearfoot portion in the front-rear direction, [0136] the fourth region is formed of the medial foot-side branch portion of the second cushion member, [0137] the fifth region is formed of the lateral foot-side branch portion of the second cushion member, and [0138] the third region is formed of a gap portion provided between the medial foot-side branch portion and the lateral foot-side branch portion of the second cushion member.

[0139] The configuration described in the above Supplementary Note 2 makes it possible to more easily configure a shoe sole that can be significantly improved in stability of a foot landing on the ground without impairing the forward propulsive force occurring when the foot pushes off from the ground.

[Supplementary Note 3]

[0140] The shoe sole according to Supplementary Note 2, wherein [0141] the first cushion member is formed of a three-dimensional structure made of resin or rubber, the three-dimensional structure including a unit structure body having a three-dimensional shape formed by a wall having an outer shape defined by a pair of parallel flat or curved surfaces, the three-dimensional structure being formed of a plurality of the unit structure bodies repeatedly arranged to be adjacent to each other, and [0142] the second cushion member is configured of a plate-shaped or block-shaped member formed of a foam material made of resin or rubber.

[0143] With the configuration described in the above Supplementary Note 3, the first cushion member deforms to buckle, which makes it possible to obtain not only the resilient force occurring when the upper-side and lower-side plates return to their original shapes but also the resilient force occurring when the buckling of the first cushion member is eliminated, so that a shoe sole further increased in forward propulsive force can be obtained.

[Supplementary Note 4]

[0144] The shoe sole according to Supplementary Note 3, wherein the unit structure body is formed by adding a thickness to each of divided structure units obtained by dividing a structure unit into two structure units in one of orthogonal three-axis directions, the structure unit being formed of a plurality of flat surfaces disposed to intersect with each other so as to be hollow inside.

[0145] The configuration described in the above Supplementary Note 4 makes it possible to further increase the resilient force occurring when the buckling of the first cushion member is eliminated, so that a shoe sole further increased in forward propulsive force can be obtained.

[Supplementary Note 5]

[0146] The shoe sole according to Supplementary Note 4, wherein the structure unit has one of a Kelvin structure, an octet structure, a cubic structure, and a cubic-octet structure.

[0147] The configuration described in the above Supplementary Note 5 makes it possible to reliably increase the resilient force occurring when the buckling of the first cushion member is eliminated.

[Supplementary Note 6]

[0148] The shoe sole according to Supplementary Note 3, wherein the unit structure body is formed by adding a thickness to each of divided structure units obtained by dividing a structure unit having a triply periodic minimal surface into two structure units in one of orthogonal three-axis directions.

[0149] The configuration described in the above Supplementary Note 6 makes it possible to further increase the resilient force occurring when the buckling of the first cushion member is eliminated, so that a shoe sole further increased in forward propulsive force can be obtained.

[Supplementary Note 7]

[0150] The shoe sole according to Supplementary Note 6, wherein the structure unit has one of a Schwartz P structure, a gyroid structure, and a Schwartz D structure.

[0151] The configuration described in the above Supplementary Note 7 makes it possible to reliably increase the resilient force occurring when the buckling of the first cushion member is eliminated.

[Supplementary Note 8]

[0152] The shoe sole according to any one of Supplementary Notes 1 to 7, wherein [0153] a first rib extending along a medial foot-side edge portion of the shoe sole is provided in a portion included in a medial foot-side end portion of the midfoot portion on a lower-side surface of the lower-side plate, and [0154] a second rib extending along a lateral foot-side edge portion of the shoe sole is provided in a portion included in a lateral foot-side end portion of the midfoot portion on the lower-side surface of the lower-side plate.

[0155] With the configuration described in the above Supplementary Note 8, the rigidity is higher in the medial foot-side portion and the lateral foot-side portion of the lower-side plate than in the central portion of the lower-side plate in the left-right direction, so that twisting of the shoe sole can be suppressed to thereby increase the stability of a foot landing on the ground.

[Supplementary Note 9]

[0156] The shoe sole according to Supplementary Note 8, wherein each of the first rib and the second rib is formed by forming the lower-side plate to be locally thicker than other portions.

[0157] The configuration described in the above Supplementary Note 9 makes it possible to more reliably suppress twisting of the shoe sole.

[Supplementary Note 10]

[0158] The shoe sole according to any one of Supplementary Notes 1 to 9, wherein at least one of a portion included in the forefoot portion of the upper-side plate and a portion included in the forefoot portion of the lower-side plate has a curved shape having a central portion bulging downward with respect to the medial foot-side end portion and the lateral foot-side end portion in the left-right direction.

[0159] The configuration described in the above Supplementary Note 10 makes it possible to increase the amount of deformation of the upper-side plate and/or the lower-side plate at the time when a foot lands on the ground, so that larger resilient force can be obtained, and therefore, the forward propulsive force occurring when the foot pushes off from the ground can be further increased.

[Supplementary Note 11]

[0160] The shoe sole according to any one of Supplementary Notes 1 to 10, wherein [0161] the lower-side plate is a spike plate provided with spikes, and [0162] a lower-side surface of the lower-side plate forms the ground contact surface.

[0163] The configuration described in the above Supplementary Note 11 makes it possible to significantly improve the stability of a foot landing on the ground, particularly in the case of a shoe sole for a spike shoe, without impairing the forward propulsive force exhibited when the foot pushes off from the ground.

[Supplementary Note 12]

[0164] A shoe including: [0165] the shoe sole according to any one of Supplementary Notes 1 to 11; and [0166] an upper provided above the shoe sole.

[0167] The configuration described in the above Supplementary Note 12 makes it possible to provide a shoe that can be significantly improved in stability of a foot landing on the ground without impairing the forward propulsive force occurring when the foot pushes off from the ground.

Other Modifications

[0168] The above embodiment has been described with regard to an example of the shoe sole and the shoe, the shoe sole having the second region provided in the substantially central portion of the midfoot portion in the front-rear direction, but the position where the second region is formed is not limited thereto. In other words, the second region should only be formed to be included at least in a portion on the rear side in the front-rear direction with respect to the first region supporting the MP joint of the wearer's foot and on the front side with respect to the rearfoot portion in the front-rear direction. Also, only a part of the above-mentioned portion may be formed as the second region, or the above-mentioned portion may be entirely formed as the second region.

[0169] Further, the above embodiment has been described with regard to an example of the shoe sole and the shoe, the shoe sole having a configuration in which the first cushion member is disposed to extend from the substantially central portion of the forefoot portion in the front-rear direction to the substantially central portion of the midfoot portion in the front-rear direction such that the same compression rigidity is achieved not only in the first region supporting the MP joint of the wearer's foot but also in the regions located on the front and rear sides of the first region. However, the region where the first region is disposed can be changed as appropriate. In other words, the region having the same compression rigidity as that in the first region can be increased or decreased in area as appropriate in the front-rear direction, and accordingly, the second region can also be increased or decreased in area or shifted in position as appropriate in the front-rear direction.

[0170] Further, the above embodiment has been described with regard to an example in which the first cushion member is formed of a three-dimensional structure provided with a plurality of protrusions and a plurality of recesses, but the first cushion member can also be formed of a foam material or a non-foam material made of resin or rubber similar to those of the second and third cushion members.

[0171] Further, the above embodiment has been described with regard to an example of the case in which the features of the present disclosure are applied to a spike shoe intended to be used exclusively for short-distance sports and a shoe sole provided therein, but the features of the present disclosure may of course be also applicable to shoes for other intended uses and shoe soles provided therein.

[0172] Although the embodiments of the present disclosure have been described, it should be understood that the embodiments disclosed herein are illustrative and not restrictive in every respect. The scope of the present disclosure is defined by the terms of the claims, and is intended to include any modifications within the meaning and scope equivalent to the terms of the appended claims.