soles and shoes equipped with them

Abstract

It provides a sole that offers high cushioning and rebound. [Solution] The sole 2A has a contact surface 2b and a support surface 2a that supports the sole of the wearer's foot, and comprises a first base portion 10 and a core portion 20. The first base portion 10 is made of foam material and consists of layered portions with the vertical direction being the thickness direction. The core portion 20 is located on the contact surface 2b side when viewed from the first base portion and is made of a foam material with lower hardness than the foam material that constitutes the first base portion 10. The core portion 20 has enlarged portions 21a, 21b whose cross-sectional area increases as you move from one of the support surface 2a side and the contact surface 2b side towards the other when the vertical direction is the axial direction. At least a part of the circumferential surface of the enlarged portions 21a, 21b is configured as an open, unrestrained surface that is not covered by other members.

Description

Technical Field

[0004] , , , ,

[0005] , , ,

[0001] The present disclosure relates to a sole and a shoe provided with the same.

Background Art

[0002] Conventionally, in order to improve cushioning, as a sole provided in a shoe, a sole provided with a foam material adjusted to a low hardness has become widespread. Examples of soles provided with a foam material adjusted to a low hardness include those disclosed in Japanese Patent Application Laid-Open No. 2021-105153 (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The sole is compressed by being sandwiched between the wearer's foot and the ground when landing, and is restored to its original shape when the sandwiching is released when taking off. A foam material with a low hardness has a larger amount of deformation when landing and a larger amount of restoration when taking off compared to a foam material with a high hardness. Therefore, a sole provided with a foam material adjusted to a low hardness not only has excellent cushioning but also has high resilience. This high resilience contributes to an improvement in the forward propulsion force during walking and running.

[0005] However, even with a sole equipped with a foam material adjusted to a low hardness, there are limitations to the cushioning and rebound properties that can be obtained when it is incorporated into the sole in a conventionally known manner. For example, even if an attempt is made to increase the amount of deformation upon ground contact by increasing the thickness of the foam material adjusted to a low hardness in order to obtain high cushioning and rebound properties, simply configuring it in this way will result in insufficient compression of the foam material upon landing, and as a result, the cushioning and rebound properties will not be sufficiently improved.

[0006] Therefore, this disclosure aims to provide a sole with improved cushioning and rebound properties, and a shoe equipped with the same. [Means for solving the problem]

[0007] A sole according to one aspect of the present disclosure has a thickness direction perpendicular to both the front-to-back direction, which is the direction corresponding to the length of the wearer's foot, and the left-to-right direction, which is the direction corresponding to the width of the wearer's foot, and its upper surface is configured as a support surface that supports the sole of the wearer's foot, and its lower surface is configured as a contact surface, and comprises a first base portion and a core portion. The first base portion is made of a foam material and consists of layered portions with the thickness direction being the vertical direction. The core portion is located on the contact surface side when viewed from the first base portion and is made of a foam material with lower hardness than the foam material that constitutes the first base portion. The core portion has at least an enlarged portion in which, when the vertical direction is considered as the axial direction, the cross-sectional area increases as it moves from one of the support surface side and the contact surface side toward the other along the axial direction. At least a part of the circumferential surface of the enlarged portion is configured as an open, unrestrained surface that is not covered by other members.

[0008] A shoe according to one aspect of the present disclosure comprises a sole according to the present aspect of the present disclosure and an upper located above the sole. [Effects of the Invention]

[0009] According to this disclosure, it will be possible to provide a sole with improved cushioning and rebound properties, and shoes equipped with the same. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic perspective view of a shoe according to Embodiment 1. [Figure 2] Figure 1 is a schematic side view of the sole as seen from the medial side of the foot. [Figure 3] Figure 1 is a schematic side view of the sole as seen from the outer side of the foot. [Figure 4] Figure 1 is a plan view of the sole. [Figure 5A] This is a schematic cross-sectional view along the VA-VA line shown in Figure 4. [Figure 5B] This is a schematic cross-sectional view along the VB-VB line shown in Figure 4. [Figure 6A] This is a schematic cross-sectional view along the VIA-VIA line shown in Figure 4. [Figure 6B] This is a schematic cross-sectional view along the VIB-VIB line shown in Figure 4. [Figure 7A] This is a schematic cross-sectional view along the VIIA-VIIA line shown in Figure 4. [Figure 7B] This is a schematic cross-sectional view along the VIIB-VIIB line shown in Figure 4. [Figure 8] Figure 1 is an exploded perspective view of the sole from a certain direction. [Figure 9] Figure 1 is an exploded perspective view of the sole from another direction. [Figure 10] Figure 1 is a schematic cross-sectional view showing the state of the shoe immediately after landing. [Figure 11] Figure 1 is a schematic cross-sectional view showing the state of the shoe after a predetermined time has elapsed since it landed on the ground. [Figure 12] This is a schematic plan view showing the case where the upper midsole is virtually removed from the sole, as shown in Figure 11. [Figure 13A] This is a schematic cross-sectional view of the sole near the core portion according to the first modified example. [Figure 13B]It is a schematic cross-sectional view near the core part of the sole according to the second modification example. [Figure 14A] It is a schematic cross-sectional view near the core part of the sole according to the third modification example. [Figure 14B] It is a schematic cross-sectional view near the core part of the sole according to the fourth modification example. [Figure 15A] It is a schematic cross-sectional view near the core part of the sole according to the fifth modification example. [Figure 15B] It is a schematic cross-sectional view near the core part of the sole according to the sixth modification example. [Figure 16] It is a schematic side view of the sole according to Embodiment 2 as viewed from the outside foot side. [Figure 17] It is an exploded perspective view of the sole shown in FIG. 16. [Figure 18A] It is a schematic cross-sectional view near the core part of the sole according to the seventh modification example. [Figure 18B] It is a schematic cross-sectional view near the core part of the sole according to the eighth modification example. [Figure 19] It is a schematic side view of the sole according to Embodiment 3 as viewed from the outside foot side. [Figure 20] It is a schematic plan view of the sole shown in FIG. 19. [Figure 21A] It is a schematic cross-sectional view taken along the line XXIA-XXIA shown in FIG. 20. [Figure 21B] It is a schematic cross-sectional view taken along the line XXIB-XXIB shown in FIG. 20. [Figure 22] It is an exploded perspective view of the sole shown in FIG. 19. [Figure 23] It is a schematic plan view showing the state where the midsole is removed from the sole shown in FIG. 19. [Figure 24] It is a schematic side view of the sole according to Embodiment 4 as viewed from the outside foot side. [Figure 25] It is a schematic plan view of the sole shown in FIG. 24. [Figure 26A] It is a schematic cross-sectional view taken along the line XXVIA-XXVIA shown in FIG. 25. [Figure 26B] It is a schematic cross-sectional view taken along the line XXVIB-XXVIB shown in FIG. 25. [Figure 27] Figure 24 shows an exploded perspective view of the sole. [Figure 28] Figure 24 is a schematic plan view showing the sole with the upper midsole and upper plate removed. [Figure 29] This is a schematic side view of the sole according to Embodiment 5, as seen from the outer foot side. [Figure 30] Figure 29 is a schematic plan view of the sole. [Figure 31A] This is a schematic cross-sectional view along the line XXXIA-XXXIA shown in Figure 30. [Figure 31B] This is a schematic cross-sectional view along the line XXXIB-XXXIB shown in Figure 30. [Figure 32] Figure 29 is an exploded perspective view of the sole. [Figure 33] Figure 29 is a schematic plan view showing the sole with the upper midsole removed. [Figure 34] This is a schematic side view of the sole according to Embodiment 6, as seen from the medial side of the foot. [Figure 35] Figure 34 is a schematic side view of the sole as seen from the outer side of the foot. [Figure 36] Figure 34 is a schematic bottom view of the sole. [Figure 37] This is a schematic side view of the sole according to Embodiment 7, as seen from the outer foot side. [Figure 38] Figure 37 is a schematic perspective view showing the sole with the outsole removed. [Figure 39] This is a schematic cross-sectional view along the line XXXIX-XXXIX shown in Figure 37. [Figure 40] This is a schematic side view of the sole according to Embodiment 8, as seen from the outer foot side. [Figure 41] Figure 40 is a schematic perspective view of the sole. [Figure 42] This is a schematic cross-sectional view along the line XLII-XLII shown in Figure 40. [Figure 43] This is a schematic side view of the sole according to Embodiment 9, as seen from the outer foot side. [Figure 44]Figure 43 is a schematic bottom view of the sole. [Modes for carrying out the invention]

[0011] The embodiments will be described in detail below with reference to the figures. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the figures, and their descriptions will not be repeated.

[0012] <Embodiment 1> Figure 1 is a schematic perspective view of a shoe according to Embodiment 1, and Figures 2 and 3 are schematic side views of the sole shown in Figure 1, viewed from the medial and lateral sides, respectively. Figure 4 is a plan view of the sole shown in Figure 1, and Figures 5A, 5B, 6A, 6B, 7A, and 7B are schematic cross-sectional views along the VA-VA line, VB-VB line, VIA-VIA line, VIB-VIB line, VIIA-VIIA line, and VIIB-VIIB line shown in Figure 4, respectively. Furthermore, Figure 8 is an exploded perspective view of the sole shown in Figure 1, viewed from one direction, and Figure 9 is an exploded perspective view of the sole shown in Figure 1, viewed from another direction. First, the configuration of the shoe 1A and the sole 2A provided therein according to this embodiment will be described with reference to Figures 1 to 9.

[0013] As shown in Figure 1, the shoe 1A comprises a sole 2A and an upper 3. The sole 2A has a substantially flattened shape with its thickness in the vertical direction, and includes an upper surface that defines a support surface 2a (see Figures 2 to 4, etc.) that supports the sole of the wearer's foot, and a lower surface that defines a contact surface 2b that lands on the ground when used during walking, running, etc. The sole 2A is a member that supports the sole of the wearer's foot. The upper 3 is located above the sole 2A and has a shape that covers almost the entire portion of the wearer's foot from the ankle to the distal end.

[0014] As shown in Figures 2 to 4, the sole 2A is divided into a forefoot R1 that supports the toes and ball of the foot, a midfoot R2 that supports the arch of the foot, and a rearfoot R3 that supports the heel of the foot, along the front-to-back direction (left-to-right direction in Figures 2 and 3, and up-to-down direction in Figure 4), which is the direction that coincides with the length of the wearer's foot when viewed from above.

[0015] Here, with the anterior end position PF of the support surface 2a of the sole 2A as the reference point, the first boundary position PB1 is defined as the position corresponding to 40% of the anterior-posterior dimension of the support surface 2a of the sole 2A from the anterior end position PF, and the second boundary position PB2 is defined as the position corresponding to 80% of the anterior-posterior dimension of the support surface 2a of the sole 2A from the anterior end position PF. In this case, the forefoot R1 corresponds to the portion included between the anterior end position PF and the first boundary position PB1 in the anterior-posterior direction, the midfoot R2 corresponds to the portion included between the first boundary position PB1 and the second boundary position PB2 in the anterior-posterior direction, and the rearfoot R3 corresponds to the portion included between the second boundary position PB2 and the posterior end position PR of the support surface 2a of the sole 2A in the anterior-posterior direction.

[0016] Furthermore, as shown in Figure 4, the sole 2A is divided into two parts along the left-right direction (left-right direction in the figure), which corresponds to the width direction of the wearer's foot when viewed from above: the medial foot portion (the S1 side in the figure), which is the midline side of the foot in its anatomical orientation (i.e., the side closer to the midline), and the lateral foot portion (the S2 side in the figure), which is the opposite side of the foot in its anatomical orientation (i.e., the side further from the midline).

[0017] Here, the boundary line that divides the sole 2A into an inner foot portion and an outer foot portion is the so-called shoe center SC. This shoe center SC is a straight line obtained when a standard wearer with feet of a size that fits the shoe 1A wears the shoe, and a straight line connecting the space between the wearer's first and second toes and the center of the calcaneus (the so-called heel center (indicated by the symbol HC in Figure 4, etc.)) is projected vertically onto the sole 2A. The anterior end position PF and posterior end position PR of the support surface 2a of the sole 2A described above are the ends of the support surface 2a of the sole 2A located on this shoe center SC.

[0018] As shown in Figure 1, the upper 3 comprises an upper body 50, a shoe tongue 51, and shoelaces 52. Of these, the shoe tongue 51 and shoelaces 52 are both fixed or attached to the upper body 50.

[0019] The upper part of the upper body 50 is provided with an upper opening that exposes the upper part of the wearer's ankle and part of the instep. On the other hand, the lower part of the upper body 50 is provided with a lower opening that is covered by the sole 2A, for example, and in other examples, the bottom is formed by sewing the lower end of the upper body 50 into a bag shape.

[0020] The shoe tongue 51 is attached to the upper body 50 by sewing, welding, bonding, or a combination thereof, so as to cover the portion of the upper opening provided in the upper body 50 that exposes a part of the wearer's instep. For the upper body 50 and shoe tongue 51, for example, woven fabric, knitted fabric, nonwoven fabric, synthetic leather, resin, etc., double raschel warp knit fabric woven with polyester yarn is used, especially in shoes where breathability and lightness are required.

[0021] The shoelace 52 is a string-like member used to pull together the edges of the upper body 50 that define the upper opening of the part covered by the tongue 51 in the left-right direction, and is inserted through a plurality of holes provided in the upper body 50 in that part. By tightening the shoelace 52 with the wearer's foot inserted into the upper body 50, the upper body 50 can be made to fit snugly against the foot.

[0022] As shown in Figures 1 to 9, the sole 2A has a midsole 10, a core 20, and an outsole 30. The midsole 10 includes an upper midsole 10A and a lower midsole 10B, and the core 20 includes a first core 20A, a second core 20B, and a third core 20C. The outsole 30 includes a front outsole 30A and a pair of rear outsoles 30B1 and 30B2.

[0023] For ease of understanding, in Figures 1 through 9, excluding Figures 5A through 7B, the midsole 10 is shown in a lighter color and the core 20 in a darker color (the same applies to Figure 12, which will be discussed later).

[0024] The midsole 10 is the base portion of the sole 2A and is continuously positioned from the forefoot R1 to the rearfoot R3 via the midfoot R2. The core 20 is positioned in a predetermined location inside the midsole 10, and the outsole 30 is positioned over almost the entire underside of the midsole 10.

[0025] As shown in Figures 1 to 9, the midsole 10 has a generally flattened, roughly plate-like shape, and its thickness is relatively thicker than that of the outsole 30. The midsole 10 includes an upper midsole 10A as a first base part and a lower midsole 10B as a second base part. The upper midsole 10A is located on the upper part of the sole 2A, and the lower midsole 10B is located on the lower part of the sole 2A.

[0026] Referring particularly to Figures 8 and 9, the upper midsole 10A includes an upper surface 10a1 and a lower surface 10b1, and the lower midsole 10B includes an upper surface 10a2 and a lower surface 10b2. The midsole 10 is formed by joining a predetermined position on the lower surface 10b1 of the upper midsole 10A and a predetermined position on the upper surface 10a2 of the lower midsole 10B by adhesive or the like, so that the upper surface 10a1 of the upper midsole 10A defines the support surface 2a of the sole 2A described above. All or part of the support surface 2a of the sole 2A is joined to the upper body 50, for example by adhesive or the like, so that the sole 2A is fixed to the upper 3 (see Figure 1).

[0027] The upper surface 10a1 of the upper midsole 10A has a shape in which its periphery is raised relative to the surrounding area. As a result, a concave portion is provided on the upper surface 10a1 of the upper midsole 10A, and this concave portion serves as the part that receives the upper 3. The upper surface 10a1 of the upper midsole 10A, excluding the periphery which is the bottom surface of this concave portion, has a smooth curved shape to fit the sole of the wearer's foot.

[0028] Here, as shown in particular in Figures 2 and 3, a recess 11a is provided on the lower surface 10b1 of the upper midsole 10A, and a recess 11b is provided on the upper surface 10a2 of the lower midsole 10B corresponding to the portion where the recess 11a is provided. As a result, a gap is formed at a predetermined position on the sole 2A where the upper midsole 10A and the lower midsole 10B are not joined together, but face each other at a predetermined distance. The core portion 20 will be placed in this gap, but the details of this will be described later.

[0029] The midsole 10, that is, in this embodiment, the upper midsole 10A and the lower midsole 10B, preferably has moderate strength while also having excellent cushioning and resilience. From this viewpoint, the midsole 10 is composed of a polymer foam material. The polymer composition includes a base polymer. The polymer composition may further include one or more selected from foaming agents, inorganic fillers, crosslinking agents, and crosslinking aids.

[0030] The above-mentioned base polymer is not particularly limited, but examples include resins, thermoplastic elastomers, and various types of rubber.

[0031] The above resins are not particularly limited, but for example, ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin block copolymer (OBC), ethylene-α-olefin random copolymer (POE), etc. can be used. These may be used individually as the base polymer, or two or more may be used simultaneously.

[0032] The thermoplastic elastomers mentioned above are not particularly limited, but for example, styrene-based thermoplastic elastomers (TPS), urethane-based thermoplastic elastomers (TPU), olefin-based thermoplastic elastomers (TPO), etc. can be used. These may be used individually as the base polymer, or two or more may be used simultaneously.

[0033] The above-mentioned rubbers are not particularly limited, but examples include natural rubber (NR), nitrile rubber (NBR), ethylene propylene diene rubber (EPDM), urethane rubber (PU), silicone rubber, and fluororubber. These may be used individually as the base polymer, or two or more may be used simultaneously.

[0034] Examples of foaming agents that can be used include organic pyrolysis-type foaming agents, inorganic pyrolysis-type foaming agents, organic foaming agents, and inorganic foaming agents.

[0035] Examples of organic pyrolysis-type blowing agents that can be used include azo compounds such as azodicarbonamide (ADCA), 1,1'-azobis(1-acetoxy-1-phenylethane), dimethyl-2,2'-azobisbutyrate, dimethyl-2,2'-azobisisobutyrate, 2,2'-azobis(2,4,4-trimethylpentane), 1,1'-azobis(cyclohexane-1-carbonitride), and 2,2'-azobis[N-(2-carboxyethyl)-2-methyl-propionamidine]; nitroso compounds such as N,N'-dinitrosopentamethylenetetramine (DPT); hydrazine derivatives such as 4,4'-oxybis(benzenesulfonyl hydrazide) and diphenylsulfon-3,3'-disulfonyl hydrazide; semicarbazide compounds such as p-toruenesulfonyl semicarbazide; and trihydrazinotriazines.

[0036] Examples of the inorganic pyrolysis-type blowing agents mentioned above include bicarbonates such as sodium bicarbonate and ammonium bicarbonate, carbonates such as sodium carbonate and ammonium carbonate, nitrites such as ammonium nitrite, and hydrogen compounds.

[0037] If the foaming agent is a thermal decomposition type foaming agent as described above, the polymer composition may contain foaming agents such as metal oxide-based foaming agents such as zinc oxide, urea-based foaming agents, salicylic acid-based foaming agents, or benzoic acid-based foaming agents.

[0038] Examples of organic blowing agents that can be used include methanol, ethanol, propane, butane, pentane, hexane, and various other aliphatic hydrocarbons.

[0039] Examples of the inorganic blowing agents mentioned above include air, carbon dioxide, nitrogen, argon, and water.

[0040] Examples of the inorganic fillers that can be used include silica particles, alumina particles, talc particles, clay particles, calcium carbonate particles, magnesium carbonate particles, aluminum hydroxide particles, and magnesium hydroxide particles. These inorganic fillers may be used individually or in combination of two or more.

[0041] Examples of crosslinking agents that can be used include organic peroxides such as dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexin-3, 1,3-bis(t-butylperoxyisopropyl)benzene, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(t-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butylperoxybenzoate, t-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, and t-butylcumyl peroxide.

[0042] Examples of crosslinking aids that can be used include divinylbenzene, trimethylolpropane trimethacrylate, 1,6-hexanediol methacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, trimellitic acid trialyl ester, trialyl cyanurate (TAC), trialyl isocyanurate (TAIC), neopentyl glycol dimethacrylate, 1,2,4-benzenetricarboxylic acid trialyl ester, tricyclodecane dimethacrylate, polyethylene glycol diacrylate, and the like.

[0043] The amount of foaming agent, crosslinking agent, etc., in the polymer composition used to form the foam can be appropriately adjusted according to the required foaming ratio, degree of crosslinking, etc.

[0044] Furthermore, the polymer composition may further contain fiber-reinforced materials such as carbon fibers and glass fibers.

[0045] As a result, the midsole 10 is generally made of a soft material with a low Young's modulus. Therefore, the midsole 10 will elastically deform relatively easily when subjected to a compressive load, resulting in excellent cushioning and rebound properties.

[0046] The upper midsole 10A and the lower midsole 10B that make up the midsole 10 may be made of the same material or of different materials.

[0047] As shown in Figures 1 to 3 and Figures 5A to 9, the outsole 30 has a generally flat, roughly plate-like shape and is relatively thinner than the midsole 10. The outsole 30 is assembled to the lower surface of the midsole 10 (more specifically, the lower surface 10b2 of the lower midsole 10B) and has a generally flat, roughly plate-like shape. In this embodiment, the outsole 30 includes a front outsole 30A and a pair of rear outsoles 30B1 and 30B2. The rear outsole 30B1 is positioned on the medial side of the sole 2A, and the rear outsole 30B2 is positioned on the lateral side of the sole 2A. Note that the outsole 30 does not need to be composed of multiple parts, and may be composed of a single component.

[0048] Referring particularly to Figures 8 and 9, the outsole 30 includes an upper surface 30a and a lower surface 30b, of which the lower surface 30b defines the contact surface 2b of the sole 2A described above. A tread pattern may be formed on the lower surface 30b of the outsole 30 by forming holes or irregularities to improve grip. The upper surface 30a of the outsole 30 is joined to the lower surface 10b2 of the lower midsole 10B, for example, by adhesive.

[0049] The outsole 30 preferably has excellent abrasion resistance and grip. From this viewpoint, the outsole 30 may be made of a material that includes, for example, a rubber material as the main component and a plasticizer, reinforcing agent, or crosslinking agent as a secondary component. Butadiene rubber can be suitably used as the rubber material.

[0050] As a result, the outsole 30 is generally made of a material with a high Young's modulus and high rigidity. In other words, the outsole 30 is made of a material with higher rigidity than the midsole 10 and core 20. Therefore, the outsole 30 has excellent durability, such as abrasion resistance.

[0051] As shown in Figures 1 to 4, 5B, 6B, 8 and 9, the core portion 20 includes a first core portion 20A, a second core portion 20B, and a third core portion 20C, each configured as a flattened, roughly ball-shaped structure. These first core portion 20A, second core portion 20B, and third core portion 20C are all held in place by the upper midsole 10A and the lower midsole 10B, respectively.

[0052] More specifically, the lower surface 10b1 of the upper midsole 10A has a recess 11a extending from the front end of the forefoot R1 to approximately the center of the midfoot R2 in the anterior-posterior direction, and the upper surface 10a2 of the lower midsole 10B also has a recess 11b extending from the front end of the forefoot R1 to approximately the center of the midfoot R2 in the anterior-posterior direction. As a result, a gap is formed in the front part of the midsole 10 where the upper midsole 10A and the lower midsole 10B are not joined but are located at a predetermined distance from each other. This gap is included in the part of the sole 2A that supports the toes of the wearer's foot and the part that supports the MP joint of the wearer's foot.

[0053] In particular, as shown in Figure 4, the first core portion 20A is positioned in the part of the sole 2A that supports the MP joint of the wearer's foot (in Figure 4, the part where the MP joint is located when worn is shown by a dashed line and is labeled MP). More specifically, the first core portion 20A is positioned to extend from the medial edge to the lateral edge of the sole 2A along the left-right direction, and its left-right ends further protrude outward from the sole 2A. In addition, the first core portion 20A is positioned to extend from the part near the posterior end of the forefoot R1 to the part near the anterior end of the midfoot R2 along the front-back direction. Thus, the first core portion 20A is positioned to encompass the part of the sole 2A that supports the MP joint of the wearer's foot and its vicinity.

[0054] Furthermore, the second core portion 20B and the third core portion 20C are located in the part of the sole 2A that supports the toes of the wearer's foot. More specifically, the second core portion 20B is located approximately in the center of the forefoot R1 in the anterior-posterior direction and on the medial side, and its medial end protrudes outward from the sole 2A. The area where this second core portion 20B is located roughly corresponds to the part of the sole 2A that supports the first toe of the wearer's foot. On the other hand, the third core portion 20C is located approximately in the center of the forefoot R1 in the anterior-posterior direction and on the lateral side, and its lateral end protrudes outward from the sole 2A. The area where this third core portion 20C is located roughly corresponds to the part of the sole 2A that supports the second, third, fourth, and fifth toes of the wearer's foot.

[0055] In this way, a gap is provided between the upper midsole 10A and the lower midsole 10B in the front portion of the sole 2A where they face each other, and the first core portion 20A, the second core portion 20B, and the third core portion 20C are placed in this gap. By joining these in the portion of the upper midsole 10A and the lower midsole 10B where they face each other but where no gap is provided, a sole 2A having the cross-sectional shape shown in Figures 5A to 7C is constructed.

[0056] In other words, the sole 2A has a configuration in which the upper midsole 10A and the lower midsole 10B are directly joined to each other at the positions marked by the VA-VA line, VIIA-VIIA line, and VIIB-VIIB line in Figure 4 and in their vicinity (i.e., the part near the front end of the forefoot R1, and from the approximately central part of the midfoot R2 in the anterior-posterior direction to the part near the rear end of the rearfoot R3). Furthermore, the sole 2A has a configuration in which the second core part 20B and the third core part 20C are sandwiched and held by the upper midsole 10A and the lower midsole 10B at the positions marked by the VB-VB line in Figure 4 and in their vicinity (i.e., the approximately central part of the forefoot R1 in the anterior-posterior direction).

[0057] Furthermore, the sole 2A has a configuration in which the first core portion 20A is sandwiched and held between the upper midsole 10A and the lower midsole 10B at the position indicated by the VIB-VIB line in Figure 4 and in its vicinity (i.e., from the part of the forefoot R1 closer to the rear end to the part of the midfoot R2 closer to the front end). In addition, the sole 2A has a configuration in which a gap is provided between the upper midsole 10A and the lower midsole 10B at the position indicated by the VIA-VIA line in Figure 4 and in its vicinity (i.e., between the approximately central part of the forefoot in the anterior-posterior direction and the part closer to the rear end). Although not shown in the cross-sectional view, the sole 2A also has a configuration in which a gap is provided between the upper midsole 10A and the lower midsole 10B in a portion of the sole 2A near the front end, and also between the upper midsole 10A and the lower midsole 10B in the space between the midfoot portion R2 of the sole 2A near the front end and approximately in the center in the anterior-posterior direction.

[0058] Here, the portion of the upper midsole 10A with the recess 11a and the portion of the lower midsole 10B with the recess 11b have a layered shape with the vertical direction being the thickness direction. Therefore, the first core portion 20A, the second core portion 20B, and the third core portion 20C are sandwiched between these layered portions of the upper midsole 10A and the lower midsole 10B, respectively.

[0059] On the other hand, as shown particularly in Figures 8 and 9, the first core portion 20A, the second core portion 20B, and the third core portion 20C all have a flattened, roughly ball-shaped form, as described above. As a result, as shown particularly in Figures 3, 4, 5B, and 6B, the first core portion 20A, the second core portion 20B, and the third core portion 20C each have a first enlarged portion 21a at their upper part, where the cross-sectional area increases as it moves from the support surface 2a side to the ground surface 2b side along the axial direction of the sole 2A, and a second enlarged portion 21b at their lower part, where the cross-sectional area increases as it moves from the ground surface 2b side to the support surface 2a side along the axial direction.

[0060] In this embodiment, the cross-sectional areas of the first core portion 20A, the second core portion 20B, and the third core portion 20C are configured to increase continuously along the axial direction toward the ground surface 2b or the support surface 2a. However, this continuous increase is not necessarily required. For example, the increase in cross-sectional area may be partially discontinuous if any of the first core portion 20A, the second core portion 20B, or the third core portion 20C has irregularities on its surface. This also applies to the following embodiments and their modifications.

[0061] Therefore, the first enlarged portion 21a of each of the first core portion 20A, the second core portion 20B, and the third core portion 20C is positioned adjacent to the lower surface 10b1 of the upper midsole 10A, and the second enlarged portion 21b of each of the first core portion 20A, the second core portion 20B, and the third core portion 20C is positioned adjacent to the upper surface 10a2 of the lower midsole 10B.

[0062] Furthermore, as shown in particular in Figures 5B, 6B, and 9, in the portion of the upper midsole 10A where the recess 11a is formed, the portion facing the first core portion 20A, the second core portion 20B, and the third core portion 20C is provided with receiving portions 12a whose shape corresponds to the shape of the apex and vicinity of the first enlarged portion 21a of the first core portion 20A, the second core portion 20B, and the third core portion 20C, respectively. The apex and vicinity of the first enlarged portion 21a of the first core portion 20A, the second core portion 20B, and the third core portion 20C, respectively, are fitted into these receiving portions 12a.

[0063] Furthermore, as shown in particular in Figures 5B, 6B, and 8, in the portion of the lower midsole 10B where the recess 11b is formed, the portion facing the first core portion 20A, the second core portion 20B, and the third core portion 20C is provided with receiving portions 12b whose shape corresponds to the shape of the apex and vicinity of the second enlargement portion 21b of each of the first core portion 20A, the second core portion 20B, and the third core portion 20C, respectively. The apex and vicinity of the second enlargement portion 21b of each of the first core portion 20A, the second core portion 20B, and the third core portion 20C are fitted into these receiving portions 12b.

[0064] As a result, each of the first core portion 20A, the second core portion 20B, and the third core portion 20C is precisely positioned and placed relative to the upper midsole 10A and the lower midsole 10B, and maintains a state in which it is sandwiched and held by the upper midsole 10A and the lower midsole 10B. It is preferable that the contact portions between each of the first core portion 20A, the second core portion 20B, and the third core portion 20C and each of the upper midsole 10A and the lower midsole 10B are joined to each other, for example, by adhesive.

[0065] The core portion 20, i.e., the first core portion 20A, the second core portion 20B, and the third core portion 20C in this embodiment, preferably has moderate strength while also having excellent cushioning and resilience. From this viewpoint, the core portion 20 is composed of a foam material of a polymer composition. The polymer composition includes a base polymer. The polymer composition may further include one or more selected from a foaming agent, an inorganic filler, a crosslinking agent, and a crosslinking aid.

[0066] Here, specific examples of the base polymer, foaming agent, inorganic filler, crosslinking agent, and crosslinking aid are the same as those of the midsole 10 described above. That is, the core portion 20 is made of the same material as the midsole 10, and may be made of the exact same material type as the material that makes up the midsole 10.

[0067] As a result, the core portion 20 is generally composed of a soft material with a low Young's modulus. Therefore, the core portion 20 will elastically deform relatively easily when subjected to a compressive load, thereby providing excellent cushioning and resilience.

[0068] However, the core portion 20 is made of a foam material with lower hardness than the foam material that makes up the midsole 10. Here, "lower hardness" means that the Asker C hardness of one component is lower than the Asker C hardness of another component. In other words, the Asker C hardness of the core portion 20 is lower than the Asker C hardness of the midsole 10.

[0069] "Asker C" is a measuring instrument for measuring hardness, and is one of the durometers (spring-type hardness testers) specified in SRIS0101 (Japan Rubber Association Standard). In this disclosure, "Asker C hardness" refers to the hardness measured using the Asker C hardness tester described above. In measuring Asker C hardness, the average value of the values ​​measured at five measurement points is adopted.

[0070] The first core portion 20A, the second core portion 20B, and the third core portion 20C included in the core portion 20 may be made of the same material or of different materials.

[0071] As shown in Figures 2, 3, 5B to 6B, 8, and 9, the upper midsole 10A and lower midsole 10B that hold the first core portion 20A, the second core portion 20B, and the third core portion 20C all have a layered shape as described above, and the first core portion 20A, the second core portion 20B, and the third core portion 20C have a flattened, roughly ball-like shape. Therefore, voids S are located exclusively around these first core portion 20A, the second core portion 20B, and the third core portion 20C. As a result, the circumferential surfaces of the first core portion 20A, the second core portion 20B, and the third core portion 20C are configured as open, unrestrained surfaces that are not covered by other members.

[0072] Specifically, as shown in Figure 6B, the upper surface of the first core portion 20A, which is the surface near the apex of the first enlarged portion 21a of the first core portion 20A, is in contact with the receiving portion 12a provided on the upper midsole 10A, thereby forming a restrained surface constrained by other members. Furthermore, the lower surface of the first core portion 20A, which is the surface near the apex of the second enlarged portion 21b of the first core portion 20A, is in contact with the receiving portion 12b provided on the lower midsole 10B, thereby forming a restrained surface constrained by other members.

[0073] On the other hand, the circumferential surface of the first core portion 20A, excluding the upper and lower surfaces, is not in contact with the upper midsole 10A and the lower midsole 10B, and is open. In particular, the portion of the circumferential surface of the first core portion 20A that protrudes outward from the inner and outer edges of the sole 2A along the left-right direction is open to the space outside the sole 2A, and the circumferential surface of the first core portion 20A, excluding these portions, is open by facing the void S provided inside the sole 2A. Therefore, the entire circumferential surface of the first core portion 20A is configured as an open, unrestrained surface that is not covered by other members.

[0074] Furthermore, as shown in Figure 5B, the upper surface of the second core portion 20B, which is the surface near the apex of the first enlarged portion 21a of the second core portion 20B, is in contact with the receiving portion 12a provided on the upper midsole 10A, thereby configuring it as a restrained surface constrained by other members. Also, the lower surface of the second core portion 20B, which is the surface near the apex of the second enlarged portion 21b of the second core portion 20B, is in contact with the receiving portion 12b provided on the lower midsole 10B, thereby configuring it as a restrained surface constrained by other members.

[0075] On the other hand, the circumferential surfaces of the second core portion 20B, excluding these upper and lower surfaces, are not in contact with the upper midsole 10A and lower midsole 10B, and are open. In particular, the portion of the circumferential surface of the second core portion 20B that protrudes from the inner foot edge of the sole 2A outward along the left-right direction is open to the space outside the sole 2A, and the circumferential surface of the second core portion 20B, excluding this portion, is open by facing the void S provided inside the sole 2A. Therefore, the entire circumferential surface of the second core portion 20B is configured as an open, unrestrained surface that is not covered by other members.

[0076] Furthermore, as shown in Figure 5B, the upper surface of the third core portion 20C, which is the surface near the apex of the first enlarged portion 21a of the third core portion 20C, is in contact with the receiving portion 12a provided on the upper midsole 10A, thereby configuring it as a restrained surface constrained by other members. Also, the lower surface of the third core portion 20C, which is the surface near the apex of the second enlarged portion 21b of the third core portion 20C, is in contact with the receiving portion 12b provided on the lower midsole 10B, thereby configuring it as a restrained surface constrained by other members.

[0077] On the other hand, the circumferential surface of the third core portion 20C, excluding these upper and lower surfaces, is not in contact with the upper midsole 10A and lower midsole 10B, and is open. In particular, the portion of the circumferential surface of the third core portion 20C that protrudes from the outer edge of the sole 2A towards the outside of the sole 2A along the left-right direction is open to the space outside the sole 2A, and the circumferential surface of the third core portion 20C, excluding this portion, is open by facing the void S provided inside the sole 2A. Therefore, the entire circumferential surface of the third core portion 20C is configured as an open, unrestrained surface that is not covered by other members.

[0078] By configuring it in this way, the sole 2A according to this embodiment and the shoe 1A equipped therewith will not only have high cushioning properties but also high rebound properties. This point will be explained in detail below.

[0079] Figure 10 is a schematic cross-sectional view showing the state of the shoe immediately after landing, as shown in Figure 1. Figure 11 is a schematic cross-sectional view showing the state of the shoe after a predetermined time has elapsed since landing, as shown in Figure 11. Figure 12 is a schematic plan view showing the state in Figure 11 with the upper midsole virtually removed from the sole. Here, "state immediately after landing" means the state just before the sole is compressed by landing, and "state after a predetermined time has elapsed" means the state after the sole has been compressed by landing. Figures 10 and 11 are schematic diagrams that include cross-sections of the sole 2A at different positions in the left-right direction.

[0080] As shown in Figure 10, just before the sole 2A is compressed by landing, the sole 2A is sandwiched between the ground 100 and the wearer's foot 200. However, since no load has yet been applied to the sole 2A, no significant deformation occurs. As time passes from this state, loads are applied to the sole 2A from the ground 100 and the wearer's foot 200, and the sole 2A undergoes compression deformation along the vertical direction as a whole.

[0081] In Figure 11, the direction of displacement occurring particularly in the front portion of the upper surface 10a1 of the upper midsole 10A (i.e., the support surface 2a of the sole 2A) due to this compressive deformation is schematically shown by white arrows. In addition, in Figures 11 and 12, the direction of displacement occurring in the first core portion 20A, the second core portion 20B, and the third core portion 20C due to this compressive deformation is schematically shown by black arrows.

[0082] As shown in Figure 11, when a load from the wearer's foot 200 is applied to the upper surface 10a1 of the upper midsole 10A, the front portion of the upper surface 10a1 of the upper midsole 10A is displaced toward the ground surface 2b, as indicated by the white arrow in the figure. In addition, a load is applied to the bottom surface 10b2 of the lower midsole 10B from the ground 100 via the outsole 30, but since the ground 100 is stationary, there is virtually no displacement on the bottom surface 10b2 of the lower midsole 10B. As a result, the front portion of the midsole 10 is compressed and deformed so that its thickness in the vertical direction decreases.

[0083] At this time, the first core section 20A, the second core section 20B, and the third core section 20C are subjected to loads along their axial direction (i.e., vertical direction) from both sides in the axial direction, causing the first core section 20A, the second core section 20B, and the third core section 20C to compress and deform so that their thickness in the vertical direction decreases. Consequently, as shown by the black arrows in the figure, the upper surfaces of the first core section 20A, the second core section 20B, and the third core section 20C are displaced toward the ground surface 2b, and the lower surfaces of the first core section 20A, the second core section 20B, and the third core section 20C are displaced toward the support surface 2a.

[0084] In this case, since the circumferential surfaces of the first core portion 20A, the second core portion 20B, and the third core portion 20C are configured as unconstrained surfaces as described above, as shown in Figures 11 and 12, the circumferential surfaces of the first core portion 20A, the second core portion 20B, and the third core portion 20C are displaced outward, thereby promoting the compressive deformation of the first core portion 20A, the second core portion 20B, and the third core portion 20C.

[0085] Furthermore, in this process, the first enlarged portion 21a and the second enlarged portion 21b of the first core portion 20A, the second core portion 20B, and the third core portion 20C, respectively, have a shape in which the cross-sectional area increases as it moves away from the upper and lower surfaces, which are the constraint surfaces of the first core portion 20A, the second core portion 20B, and the third core portion 20C. Therefore, in this respect as well, the first core portion 20A, the second core portion 20B, and the third core portion 20C are efficiently compressed and deformed, and their compression deformation is promoted.

[0086] As described above, the first core portion 20A, the second core portion 20B, and the third core portion 20C included in the core portion 20 are made of a material with lower hardness than the midsole 10 which consists of the upper midsole 10A and the lower midsole 10B. Therefore, in this respect as well, the compressive deformation of the first core portion 20A, the second core portion 20B, and the third core portion 20C is promoted.

[0087] Therefore, by adopting the above configuration, the amount of deformation associated with the compression deformation of the sole 2A increases in the region where the core 20 is located and its vicinity, thereby improving cushioning performance. Furthermore, the amount of recovery during unloading also increases, resulting in improved rebound performance. In other words, by adopting the above configuration, improvements are made not only in terms of materials but also in terms of structure, enabling the realization of unprecedented cushioning and rebound performance.

[0088] In other words, even when attempting to increase the amount of deformation upon contact by increasing the thickness of a low-hardness foam material in order to improve cushioning and rebound properties, simply increasing the thickness of a single layer of foam material will result in insufficient compression of the foam material. However, by adopting a configuration as in this embodiment, the compressive deformation is structurally promoted, and as a result, improvements in cushioning and rebound properties due to the increased thickness of the foam material can be achieved.

[0089] As described above, by using the sole 2A according to this embodiment and the shoe 1A equipped therewith, higher cushioning and rebound properties can be obtained than in conventional designs.

[0090] As described above, in this embodiment, the core portion 20 is positioned in the portion of the sole 2A that supports the MP joint of the wearer's foot and the portion that supports the toes of the wearer's foot. With this configuration, the high rebound force generated by the sole 2A can be appropriately applied to the MP joint and toes of the wearer's foot, which are the parts that strongly push off the ground when pushing off. As a result, forward propulsion is improved, and efficient walking and running can be achieved.

[0091] Furthermore, in order to obtain high propulsion force when pushing off, it is preferable that the support surface of the front part of the sole be lower in height at landing (i.e., a smaller distance from the ground) than the support surface of the rear part of the sole, which supports the heel of the wearer's foot. In the sole 2A and the shoe 1A equipped therewith according to this embodiment, as shown in Figure 10, a core part 20 is provided on the front part of the sole 2A, so that their heights are approximately the same when there is no load.

[0092] However, as shown in Figure 11, when the sole 2A undergoes compression deformation upon landing, as described above, significant compression deformation occurs particularly in the front portion of the sole 2A. Therefore, during push-off, the position of the support surface on the front portion of the sole 2A naturally becomes lower than the position of the support surface on the rear portion of the sole 2A. Consequently, by adopting the above configuration, even when the thickness of the front portion of the sole 2A is increased, it is possible to obtain high propulsion force during push-off, and the weight transfer from landing to push-off becomes smoother.

[0093] In this regard, in the portion where the core portion 20 is provided, the thickness of the core portion 20 relative to the total thickness of the midsole 10 and the core portion 20 can be, for example, 10% or more. Furthermore, if the thickness of the core portion 20 relative to the total thickness of the midsole 10 and the core portion 20 is 30% or more, good cushioning and rebound properties can be obtained, and if it is 50% or more, even better cushioning and rebound properties can be obtained.

[0094] Furthermore, as in this embodiment, by making the shape of the core portion 20 a flattened, roughly ball-like shape, when viewed from above, the core portion 20 deforms to expand upon landing, thus ensuring stability upon landing.

[0095] <Variations 1 through 6> Figures 13A, 13B, 14A, 14B, 15A, and 15B are schematic cross-sectional views of the vicinity of the core portion of the sole according to the first to sixth modified examples, respectively. Hereinafter, the soles 2A1 to 2A6 according to the first to sixth modified examples based on the above-described embodiment 1 will be described with reference to these figures 13A to 15B. Note that the soles 2A1 to 2A6 according to the first to sixth modified examples are provided in the shoe 1A in place of the sole 2A according to the above-described embodiment 1.

[0096] In the embodiment 1 described above, a sole 2A having a core portion 20 having a flattened, substantially ball-shaped form was exemplified. However, the shape of the core portion 20 can be configured in any shape as long as it has an enlarged portion in which the cross-sectional area increases from one of the support surface 2a side and the contact surface 2b side towards the other along the axial direction.

[0097] As shown in Figures 13A and 13B, in the soles 2A1 and 2A2 according to the first and second modified examples, the core portion 20 is configured to have a flattened, semi-ball-shaped form.

[0098] As shown in Figure 13A, in the sole 2A1 according to the first modified example, the core portion 20 is positioned such that the curved portion of the core portion 20 faces the upper midsole 10A side, and the flat portion of the core portion 20 faces the lower midsole 10B side. In this configuration, the core portion 20 has only a first enlarged portion 21a whose cross-sectional area increases as it moves along the axial direction from the support surface 2a side to the contact surface 2b side.

[0099] As shown in Figure 13B, in the sole 2A2 according to the second modified example, the core portion 20 is positioned such that the flat portion of the core portion 20 faces the upper midsole 10A side, and the curved portion of the core portion 20 faces the lower midsole 10B side. In this configuration, the core portion 20 has only a second enlarged portion 21b whose cross-sectional area increases as it moves along the axial direction from the contact surface 2b side to the support surface 2a side.

[0100] As shown in Figures 14A and 14B, in the soles 2A3 and 2A4 according to the third and fourth modified examples, the core portion 20 is configured to have a frustoconical shape.

[0101] As shown in Figure 14A, in the sole 2A3 according to the third modified example, the core portion 20 is positioned such that the smaller of the pair of planar portions of the core portion 20 faces the upper midsole 10A side, and the larger of the pair of planar portions of the core portion 20 faces the lower midsole 10B side. In this configuration, the core portion 20 has only a first enlarged portion 21a whose cross-sectional area increases as it moves along the axial direction from the support surface 2a side to the contact surface 2b side.

[0102] As shown in Figure 14B, in the sole 2A4 according to the fourth modified example, the core portion 20 is positioned such that the larger of the pair of planar portions of the core portion 20 faces the upper midsole 10A side, and the smaller of the pair of planar portions of the core portion 20 faces the lower midsole 10B side. In this configuration, the core portion 20 has only a second enlarged portion 21b whose cross-sectional area increases as it moves along the axial direction from the contact surface 2b side to the support surface 2a side.

[0103] As shown in Figure 15A, in the sole 2A5 according to the fifth modified example, the core portion 20 is configured to have a substantially cylindrical shape with a constricted central portion in the axial direction. In this configuration, the core portion 20 has a first enlarged portion 21a whose cross-sectional area increases as it moves along the axial direction from the support surface 2a to the contact surface 2b, and a second enlarged portion 21b whose cross-sectional area increases as it moves along the axial direction from the contact surface 2b to the support surface 2a. The second enlarged portion 21b is positioned closer to the upper midsole 10A, and the first enlarged portion 21a is positioned closer to the lower midsole 10B.

[0104] As shown in Figure 15B, in the sole 2A6 according to the sixth modified example, the core portion 20 is configured to have a roughly ball-like shape with a constricted central portion in the axial direction. In this configuration, the core portion 20 alternately has a first enlarged portion 21a whose cross-sectional area increases as it moves axially from the support surface 2a side to the contact surface 2b side, and a second enlarged portion 21b whose cross-sectional area increases as it moves axially from the contact surface 2b side to the support surface 2a side. More specifically, these are arranged in the order of first enlarged portion 21a, second enlarged portion 21b, first enlarged portion 21a, second enlarged portion 21b, from the side where the upper midsole 10A is located to the side where the lower midsole 10B is located.

[0105] Even when the core portion 20 is shaped in this way, effects similar to those described in Embodiment 1 above can be obtained. It is also possible to make the core portion 20 spherical, rugby ball-shaped, truncated pyramidal, or the like.

[0106] <Embodiment 2> Figure 16 is a schematic side view of the sole according to Embodiment 2, viewed from the outer foot side, and Figure 17 is an exploded perspective view of the sole shown in Figure 16. For ease of understanding, in Figures 16 and 17, the midsole 10 is colored lightly and the core portion 20 is colored darkly. The shoe 1B according to this embodiment and the sole 2B provided therein will be described below with reference to Figures 16 and 17. The upper (not shown) provided by the shoe 1B according to this embodiment is the same as the upper 3 provided by the shoe 1A according to Embodiment 1 described above.

[0107] As shown in Figures 16 and 17, the sole 2B according to this embodiment differs from the sole 2A according to Embodiment 1 described above mainly in that it further includes an upper plate 40A.

[0108] Specifically, the upper plate 40A, which is a plate-shaped first high-hardness portion, is embedded inside the midsole 10 so as to extend from the part of the forefoot R1 of the sole 2B near the front to the part of the midfoot R2 of the sole 2B. The upper plate 40A is configured to be wide, particularly in the part located from the part of the forefoot R1 near the front to the part of the midfoot R2 near the front, so as to extend to the medial and lateral edges of the sole 2B. This upper plate 40A increases the forward propulsion force during push-off by suppressing dorsiflexion that occurs in the sole, especially during running.

[0109] Unlike in the first embodiment described above, the lower surface 10b1 of the upper midsole 10A does not have a recess 11a (see Figures 2, 3, 9, etc.), and only the upper surface 10a2 of the lower midsole 10B has a recess 11b similar to that in the first embodiment described above. As a result of this recess 11b being provided on the upper surface 10a2 of the lower midsole 10B, a gap is formed in the front part of the midsole 10 where the upper midsole 10A and the lower midsole 10B are not joined but are located at a predetermined distance from each other, and the first core part 20A, the second core part 20B, and the third core part 20C, which constitute the core part 20, are arranged in this gap.

[0110] The upper plate 40A is positioned between the upper midsole 10A and the lower midsole 10B. The upper plate 40A is positioned along the lower surface 10b1 of the upper midsole 10A, so that in the areas where the first core portion 20A, the second core portion 20B, and the third core portion 20C are located, the upper plate 40A is positioned above each of these first core portion 20A, second core portion 20B, and third core portion 20C.

[0111] The upper plate 40A, positioned between the upper midsole 10A and the first core portion 20A, the second core portion 20B, and the third core portion 20C, is joined to the lower surface 10b1 of the upper midsole 10A, for example by adhesive, and the upper ends of the first core portion 20A, the second core portion 20B, and the third core portion 20C are joined to the upper plate 40A, for example by adhesive.

[0112] The upper plate 40A is made of a material that is harder than the materials that make up the midsole 10 and core 20, and its material is not particularly limited. Examples of materials for the upper plate 40A include fiber-reinforced resins using carbon fiber, glass fiber, aramid fiber, Dyneema fiber (registered trademark), Zylon fiber (registered trademark), boron fiber, etc. as reinforcing fibers and epoxy resin, polyester resin, phenolic resin, polyamide resin, polypropylene resin, polyethylene resin, polyurethane resin, etc. as the base material, or non-fiber-reinforced resins made of polymer resins such as urethane thermoplastic elastomer (TPU), amide thermoplastic elastomer (TPA), ethylene-vinyl acetate copolymer (EVA).

[0113] Even when the shoe 1B and sole 2B according to this embodiment described above are used, effects similar to those described in Embodiment 1 above can be obtained, and higher cushioning and rebound performance can be obtained than in the conventional. In particular, when the configuration as in this embodiment is adopted, the rebound performance obtained by providing the core portion 20 made of low-hardness foam material to the sole 2B and the rebound performance obtained by providing the upper plate 40A to the sole 2B combine to make it possible to obtain even higher rebound performance.

[0114] <Variations 7 and 8> Figures 18A and 18B are schematic cross-sectional views of the vicinity of the core portion of the sole according to the seventh and eighth modified examples, respectively. The soles 2B1 and 2B2 according to the seventh and eighth modified examples based on the above-described embodiment 2 will be described below with reference to Figures 18A and 18B. Note that the soles 2B1 and 2B2 according to the seventh and eighth modified examples are provided in the shoe 1B in place of the sole 2B according to the above-described embodiment 2.

[0115] In the above-described embodiment 2, an example was given in which a plate made of a material with higher hardness than the materials constituting the midsole 10 and core portion 20 is placed above the core portion 20. However, the placement position of the plate is not particularly limited to this.

[0116] As shown in Figure 18A, in the sole 2B1 according to the seventh modified example, the lower plate 40B, which is a plate-shaped second high-hardness part, is arranged along the upper surface 10a2 of the lower midsole 10B, and in the portion where the core part 20 is located, the lower plate 40B is located below each of the core parts 20.

[0117] The lower plate 40B, positioned between the lower midsole 10B and the core 20, is joined to the upper surface 10a2 of the lower midsole 10B, for example by adhesive, and the lower end of the core 20 is joined to the lower plate 40B, for example by adhesive.

[0118] Furthermore, the lower plate 40B, like the upper plate 40A described above, only needs to be made of a material with higher hardness than the materials constituting the midsole 10 and core 20, and can be made of the same material as the upper plate 40 described above.

[0119] As shown in Figure 18B, the sole 2B2 according to the eighth modified example comprises an upper plate 40A as a plate-shaped first high-hardness portion and a lower plate 40B as a plate-shaped second high-hardness portion. In this sole 2B2, the upper plate 40A is positioned on the lower surface 10b1 of the upper midsole 10A, and the lower plate 40B is positioned on the upper surface 10a2 of the lower midsole 10B, so that the upper end of the core portion 20 is fixed to the upper plate 40A and the lower end of the core portion 20 is fixed to the lower plate 40B.

[0120] Even when a plate made of a material with higher hardness than the materials constituting the midsole 10 and core portion 20 is placed in such a position, effects similar to those described in Embodiment 2 above can be obtained.

[0121] <Embodiment 3> Figure 19 is a schematic side view of the sole according to Embodiment 3, viewed from the outer foot side, and Figure 20 is a schematic plan view of the sole shown in Figure 19. Figures 21A and 21B are schematic cross-sectional views along the XXIA-XXIA line and XXIB-XXIB line shown in Figure 20, respectively. Figure 22 is an exploded perspective view of the sole shown in Figure 19, and Figure 23 is a schematic plan view showing the sole shown in Figure 19 with the midsole removed. The shoe 1C and the sole 2C provided therein according to this embodiment will be described below with reference to Figures 19 to 23. The upper (not shown) provided by the shoe 1C according to this embodiment is the same as the upper 3 provided by the shoe 1A according to Embodiment 1 described above.

[0122] As shown in Figures 19 to 23, the sole 2C according to this embodiment differs from the sole 2A according to Embodiment 1 described above mainly in that the midsole 10 is not composed of two members, an upper midsole 10A and a lower midsole 10B, but is composed of a single member.

[0123] Specifically, the sole 2B comprises a midsole 10 as the first base portion, a first core portion 20A, a second core portion 20B, and a third core portion 20C as the core portion 20, and a front outsole 30A and a rear outsole 30B as the outsole 30.

[0124] For ease of understanding, in Figures 19 through 23, excluding Figures 21A and 21B, the midsole 10 is shown in a lighter color, and the core 20 is shown in a darker color.

[0125] Referring particularly to Figure 22, the midsole 10 includes an upper surface 10a and a lower surface 10b, of which the upper surface 10a defines the support surface 2a of the sole 2C. Furthermore, the lower surface 10b of the midsole 10 has a recess 11a extending from the part near the front end of the forefoot R1 to approximately the center in the anterior-posterior direction of the midfoot R2.

[0126] As shown in Figures 19 to 23, the first core portion 20A, the second core portion 20B, and the third core portion 20C are all configured in a flat, roughly ball-like shape, and each of them is positioned in a recess 11a provided in the midsole 10 described above. In particular, as shown in Figure 20, the first core portion 20A is positioned in the portion of the sole 2C that supports the MP joint of the wearer's foot, and the second core portion 20B and the third core portion 20C are positioned in the portion of the sole 2C that supports the toes of the wearer's foot.

[0127] As shown in Figures 19 and 21A to 23, the outsole 30 is positioned to cover the lower surface 10b of the midsole 10 and the lower surfaces of the first core portion 20A, the second core portion 20B, and the third core portion 20C, respectively. As a result, the first core portion 20A, the second core portion 20B, and the third core portion 20C are held in place by being sandwiched between the midsole 10 and the outsole 30.

[0128] More specifically, the upper surfaces of the first core portion 20A, the second core portion 20B, and the third core portion 20C are joined to the lower surface 10b of the midsole 10 in the portion where the recess 11a is provided, for example by adhesive, and the lower surfaces of the first core portion 20A, the second core portion 20B, and the third core portion 20C are joined to the upper surface 30a of the outsole 30, for example by adhesive. As a result, the first core portion 20A, the second core portion 20B, and the third core portion 20C are fixed immovably to both the midsole 10 and the outsole 30.

[0129] In this embodiment, the outsole 30 is composed of two components, a front outsole 30A and a rear outsole 30B, as described above. The front outsole 30A is positioned to cover a recess 11 provided on the lower surface 10b of the midsole 10. As a result, the lower surfaces of the first core portion 20A, the second core portion 20B, and the third core portion 20C are fixed to the front outsole 30A. The lower surfaces 30b of the front outsole 30A and the rear outsole 30B each define the contact surface 2b of the sole 2C.

[0130] As shown in Figures 19, 21A, 21B, and 22, the midsole 10 that holds the first core portion 20A, the second core portion 20B, and the third core portion 20C is configured to have a layered shape, and the first core portion 20A, the second core portion 20B, and the third core portion 20C have a flattened, roughly ball-like shape. Therefore, voids S are located around these first core portion 20A, the second core portion 20B, and the third core portion 20C.

[0131] As a result, in the sole 2C according to this embodiment, similar to the first embodiment described above, the circumferential surfaces of the first core portion 20A, the second core portion 20B, and the third core portion 20C are configured as open, unconstrained surfaces that are not covered by other members. Furthermore, these circumferential surfaces of the first core portion 20A, the second core portion 20B, and the third core portion 20C, configured as unconstrained surfaces, are the surfaces of the portions corresponding to the first enlarged portion 21a and the second enlarged portion 21b of the first core portion 20A, the second core portion 20B, and the third core portion 20C.

[0132] Therefore, even when using the shoe 1C and sole 2C provided therein according to the embodiment described above, effects similar to those described in Embodiment 1 above can be obtained, and higher cushioning and rebound performance can be obtained than in the conventional design.

[0133] <Embodiment 4> Figure 24 is a schematic side view of the sole according to Embodiment 4, viewed from the outer foot side, and Figure 25 is a schematic plan view of the sole shown in Figure 24. Figures 26A and 26B are schematic cross-sectional views along the XXVIA-XXVIA and XXVIB-XXVIB lines shown in Figure 25, respectively. Figure 27 is an exploded perspective view of the sole shown in Figure 24, and Figure 28 is a schematic plan view showing the sole shown in Figure 24 with the upper midsole and upper plate removed. The shoe 1D according to this embodiment and the sole 2D provided therein will be described below with reference to Figures 24 to 28. The upper (not shown) provided by the shoe 1D according to this embodiment is the same as the upper 3 provided by the shoe 1A according to Embodiment 1 described above.

[0134] As shown in Figures 24 to 28, the sole 2D according to this embodiment, similar to the sole 2B according to Embodiment 2 described above, includes a midsole 10 consisting of an upper midsole 10A as a first base portion and a lower midsole 10B as a second base portion, a core portion 20 consisting of a first core portion 20A, a second core portion 20B and a third core portion 20C, an outsole 30 consisting of a front outsole 30A and a pair of rear outsoles 30B1 and 30B2, and an upper plate 40A as a plate-shaped first high-hardness portion.

[0135] For ease of understanding, in Figures 24 through 28, excluding Figures 26A and 26B, the midsole 10 is shown in a lighter color, and the core portion 20 is shown in a darker color.

[0136] In the sole 2D according to this embodiment, the core portion 20 is configured to include a first core portion 20A, a second core portion 20B, and a third core portion 20C, each having a flattened, substantially ball-shaped form, similar to the sole 2B according to the second embodiment described above. However, unlike the sole 2B according to the second embodiment described above, the configuration differs in that these first core portion 20A, second core portion 20B, and third core portion 20C are interconnected.

[0137] Specifically, as shown in Figures 25, 27, and 28, the first core portion 20A is positioned in the part of the sole 2D that supports the MP joint of the wearer's foot, the second core portion 20B is positioned in the part that supports the first toe of the wearer's foot, and the third core portion 20C is positioned in the part that supports the second, third, fourth, and fifth toes of the wearer's foot. Of these, the second core portion 20B is connected to the first core portion 20A in the part facing the first core portion 20A, and the third core portion 20C is connected to the first core portion 20A in the part facing the first core portion 20A.

[0138] By configuring it in this way, the core portion 20 is made up of a single component in which the first core portion 20A, the second core portion 20B, and the third core portion 20C are connected to each other. This reduces the number of parts, improving ease of assembly during the manufacturing of the sole 2D, and also improves durability by simplifying the structure.

[0139] Here, as shown in particular in Figures 24, 26A to 28, in the sole 2D according to this embodiment, similar to the second embodiment described above, a gap is provided between the upper midsole 10A and the lower midsole 10B in the front portion of the sole 2D where they face each other, and the first core portion 20A, the second core portion 20B, and the third core portion 20C are arranged in this gap, and a void S is located around these first core portion 20A, the second core portion 20B, and the third core portion 20C, so that their circumferential surfaces are open and unrestrained surfaces that are not covered by other members.

[0140] Furthermore, the circumferential surfaces of the first core portion 20A, the second core portion 20B, and the third core portion 20C, which are configured as unconstrained surfaces, are the surfaces of the portions corresponding to the first enlarged portion 21a and the second enlarged portion 21b of the first core portion 20A, the second core portion 20B, and the third core portion 20C.

[0141] Therefore, even when using the shoe 1D and sole 2D according to the embodiment described above, effects similar to those described in Embodiment 2 above can be obtained, and higher cushioning and rebound performance can be obtained than in the conventional design.

[0142] Furthermore, when connecting the first core section 20A, the second core section 20B, and the third core section 20C to each other, they may be connected by providing, for example, a roughly columnar bridge section between adjacent sections, or, as in this embodiment, they may be connected so that the enlarged sections of adjacent sections are directly continuous without providing such a bridge section.

[0143] <Embodiment 5> Figure 29 is a schematic side view of the sole according to Embodiment 5, viewed from the outer foot side, and Figure 30 is a schematic plan view of the sole shown in Figure 29. Figures 31A and 31B are schematic cross-sectional views along the lines XXXIA-XXXIA and XXXIB-XXXIB shown in Figure 30, respectively. Figure 32 is an exploded perspective view of the sole shown in Figure 29, and Figure 33 is a schematic plan view showing the sole shown in Figure 29 with the upper midsole removed. The shoe 1E according to this embodiment and the sole 2E provided therein will be described below with reference to Figures 29 to 33. The upper (not shown) provided by the shoe 1E according to this embodiment is the same as the upper 3 provided by the shoe 1A according to Embodiment 1 described above.

[0144] As shown in Figures 29 to 33, the sole 2E according to this embodiment differs from the sole 2A according to Embodiment 1 described above in the configuration of the core portion 20. More specifically, in the sole 2E according to this embodiment, the core portion 20 is composed of an inner foot side first core portion 20A1, an outer foot side first core portion 20A2, a second core portion 20B, a third core portion 20C, and a fourth core portion 20D, and differs from the sole 2A according to Embodiment 1 described above in that a portion of the circumferential surface of each of these is constrained by other members.

[0145] Here, for the sake of ease of understanding, in Figures 29 through 33, excluding Figures 31A and 31B, the midsole 10 is given a light color and the core portion 20 is given a dark color.

[0146] In particular, as shown in Figure 30, the medial first core portion 20A1 and the lateral first core portion 20A2 are located in the part of the sole 2E that supports the MP joint of the wearer's foot. More specifically, the medial first core portion 20A1 is located in the medial part, from the part near the posterior end of the forefoot R1 to the part near the anterior end of the midfoot R2, and the lateral first core portion 20A2 is located in the lateral part, from the part near the posterior end of the forefoot R1 to the part near the anterior end of the midfoot R2. The part where the medial first core portion 20A1 is located corresponds to the part of the sole 2E that supports the medial part of the MP joint of the wearer's foot (i.e., the part on the ball of the big toe side), and the part where the lateral first core portion 20A2 is located corresponds to the part of the sole 2E that supports the lateral part of the MP joint of the wearer's foot (i.e., the part on the ball of the little toe side).

[0147] Furthermore, the second core portion 20B, the third core portion 20C, and the fourth core portion 20D are located in the part of the sole 2E that supports the toes of the wearer's foot. More specifically, the second core portion 20B is located approximately in the center of the forefoot R1 in the anterior-posterior direction and on the medial side, and the third core portion 20C is located approximately in the center of the forefoot R1 in the anterior-posterior direction and on the lateral side. On the other hand, the fourth core portion 20D is located approximately in the center of the forefoot R1 in both the anterior-posterior direction and the lateral direction. The portion where the second core portion 20B is located corresponds to the part of the sole 2E that supports the first toe of the wearer's foot, and the portion where the third core portion 20C is located corresponds to the part of the sole 2E that supports the fourth and fifth toes of the wearer's foot. On the other hand, the area where the fourth core portion 20D is located roughly corresponds to the part of the sole 2E that supports the wearer's second and third toes.

[0148] As shown in Figures 29, 31A to 32, the upper midsole 10A and lower midsole 10B that hold the medial first core portion 20A1, the lateral first core portion 20A2, the second core portion 20B, the third core portion 20C, and the fourth core portion 20D all have a generally layered shape, and the medial first core portion 20A1, the lateral first core portion 20A2, the second core portion 20B, the third core portion 20C, and the fourth core portion 20D all have a flattened, roughly ball-like shape. Therefore, a void S is located mainly around a part of these medial first core portion 20A1, the lateral first core portion 20A2, the second core portion 20B, the third core portion 20C, and the fourth core portion 20D. As a result, the circumferential surfaces of the first core portion 20A, the second core portion 20B, and the third core portion 20C are configured as unrestrained surfaces, with most of them open and not covered by other members.

[0149] More specifically, as shown in Figure 29, the portions of the circumferential surfaces of the medial foot side first core portion 20A1, the outer foot side first core portion 20A2, the second core portion 20B, the third core portion 20C, and the fourth core portion 20D that are located in the front-to-back direction are in contact with the upper midsole 10A and the lower midsole 10B, and are thus configured as restrained surfaces constrained by other members. However, as shown in Figures 31A and 31B, the portions of the circumferential surfaces of the medial foot side first core portion 20A1, the outer foot side first core portion 20A2, the second core portion 20B, the third core portion 20C, and the fourth core portion 20D that are located in the left-to-right direction are open, either facing the outside of the sole 2E or facing a void S provided inside the sole 2E. Therefore, the circumferential surfaces of the inner foot side first core portion 20A1, the outer foot side first core portion 20A2, the second core portion 20B, the third core portion 20C, and the fourth core portion 20D are configured as unrestrained surfaces, with most of them open and not covered by other members.

[0150] Furthermore, the circumferential surfaces of the inner foot side first core portion 20A1, outer foot side first core portion 20A2, second core portion 20B, third core portion 20C, and fourth core portion 20D, which are configured as unconstrained surfaces, are the surfaces of the portions corresponding to the first enlarged portion 21a and the second enlarged portion 21b of the inner foot side first core portion 20A1, outer foot side first core portion 20A2, second core portion 20B, third core portion 20C, and fourth core portion 20D.

[0151] Therefore, even when using the shoe 1E and sole 2E according to the embodiment described above, effects similar to those described in Embodiment 1 above can be obtained, and higher cushioning and rebound performance can be obtained than in the conventional design.

[0152] Furthermore, as in this embodiment, if a portion of the circumferential surfaces of the inner foot side first core portion 20A1, the outer foot side first core portion 20A2, the second core portion 20B, the third core portion 20C, and the fourth core portion 20D are configured as restraining surfaces, it becomes possible to ensure greater stability during landing.

[0153] <Embodiment 6> Figure 34 is a schematic side view of the sole according to Embodiment 6, viewed from the inner foot side, and Figure 35 is a schematic side view of the sole shown in Figure 34, viewed from the outer foot side. Figure 36 is a schematic bottom view of the sole shown in Figure 34. The shoe 1F and the sole 2F provided therein according to this embodiment will be described below with reference to Figures 34 to 36. The upper (not shown) provided by the shoe 1F according to this embodiment is the same as the upper 3 provided by the shoe 1A according to Embodiment 1 described above.

[0154] As shown in Figures 34 to 36, the sole 2F according to this embodiment differs from the sole 2A according to Embodiment 1 described above in the configuration of the midsole 10 and the core portion 20, and also differs in that it does not have an outsole 30 (see Figure 1, etc.). More specifically, in the sole 2F according to this embodiment, the midsole 10 is made of a single member, and the core portion 20 includes an inner foot side first core portion 20A1 and an outer foot side first core portion 20A2.

[0155] For ease of understanding, in Figures 34 to 36, the midsole 10 is shown in a lighter color, and the core portion 20 is shown in a darker color. In this embodiment, the sole 2F does not have an outsole, but this may be provided separately.

[0156] The midsole 10 includes an upper surface 10a and a lower surface 10b. The upper surface 10a defines the support surface 2a of the sole 2F, and the lower surface 10b defines the contact surface 2b of the sole 2F. In addition, the lower surfaces of the medial first core portion 20A1 and the lateral first core portion 20A2 also define the contact surface 2b of the sole 2F.

[0157] The medial first core portion 20A1 and the lateral first core portion 20A2 are both configured in a flat, roughly ball shape and are positioned in the portion of the sole 2F that supports the MP joint of the wearer's foot. More specifically, the medial first core portion 20A1 is located on the medial side, extending from the posterior end portion of the forefoot R1 to the anterior end portion of the midfoot R2, and the lateral first core portion 20A2 is located on the lateral side, extending from the posterior end portion of the forefoot R1 to the posterior end portion of the midfoot R2. The lower surface 10b of the midsole 10 in the portion where these medial first core portions 20A1 and lateral first core portions 20A2 are provided has recesses 11a of corresponding shapes, into which the medial first core portion 20A1 and lateral first core portion 20A2 are fitted.

[0158] The midsole 10 that holds the medial first core portion 20A1 and the lateral first core portion 20A2 has a generally layered shape, and as described above, both the medial first core portion 20A1 and the lateral first core portion 20A2 have a flattened, roughly ball-shaped form. Therefore, both the medial first core portion 20A1 and the lateral first core portion 20A2 have a first enlarged portion 21a and a second enlarged portion 21b, and in particular, the circumferential surfaces of the medial first core portion 20A1 and the lateral first core portion 20A2 corresponding to the lower part of the first enlarged portion 21a and the second enlarged portion 21b are configured as unrestrained surfaces that are not covered by other members.

[0159] Therefore, even when using the shoe 1F and sole 2F according to the embodiment described above, effects similar to those described in Embodiment 1 above can be obtained, and higher cushioning and rebound performance can be obtained than in the conventional design.

[0160] Furthermore, the portion of the outer foot where the outer foot side first core portion 20A2 is located, from the part near the rear end of the forefoot portion R1 to the part near the rear end of the midfoot portion R2, and which is on the outer foot side, is usually the part that first makes contact with the ground during landing, and a relatively large load acts as a reaction force on the wearer's foot in this portion. Therefore, by extending the outer foot side first core portion 20A2 to this portion, cushioning performance can be particularly improved.

[0161] <Embodiment 7> Figure 37 is a schematic side view of the sole according to Embodiment 7, viewed from the outer foot side, and Figure 38 is a schematic perspective view showing the sole shown in Figure 37 with the outsole removed. Figure 39 is a schematic cross-sectional view along the line XXXIX-XXXIX shown in Figure 37. The shoe 1G according to this embodiment and the sole 2G provided therein will be described below with reference to Figures 37 to 39. The upper (not shown) provided by the shoe 1G according to this embodiment is the same as the upper 3 provided by the shoe 1A according to Embodiment 1 described above.

[0162] As shown in Figures 37 to 39, the sole 2G according to this embodiment differs from the sole 2A according to Embodiment 1 described above in the configuration of the midsole 10 and core portion 20, and accordingly the configuration of the outsole 30 also differs.

[0163] Specifically, the sole 2G comprises a midsole 10 consisting of an upper midsole 10A and a pair of lower midsoles 10B1 and 10B2, a core 20 consisting of an inner foot first core 20A1 and an outer foot first core 20A2, and an outsole 30 consisting of a front outsole 30A1 to 30A3 and a rear outsole 30B.

[0164] For ease of understanding, in Figures 37 and 38, the midsole 10 is shown in a lighter color, and the core portion 20 is shown in a darker color.

[0165] The upper midsole 10A includes an upper surface 10a1 and a lower surface 10b1, of which the upper surface 10a1 defines the support surface 2a of the sole 2G. Furthermore, as shown in particular in Figure 37, the lower surface 10b1 of the upper midsole 10A is provided with a recess 11a extending from approximately the center of the forefoot R1 in the anterior-posterior direction to approximately the center of the midfoot R2 in the anterior-posterior direction.

[0166] The medial first core portion 20A1 and the lateral first core portion 20A2 are both configured in a flattened, roughly ball shape, and both are positioned in the recess 11a provided in the upper midsole 10A described above. The medial first core portion 20A1 and the lateral first core portion 20A2 are positioned in the portion of the sole 2G that supports the MP joint of the wearer's foot. More specifically, the medial first core portion 20A1 is located from approximately the center of the forefoot R1 in the anterior-posterior direction to approximately the center of the midfoot R2 in the anterior-posterior direction and is on the medial side, and the lateral first core portion 20A2 is located from approximately the center of the forefoot R1 in the anterior-posterior direction to approximately the center of the midfoot R2 in the anterior-posterior direction and is on the lateral side.

[0167] As shown in Figures 37 to 39, the pair of lower midsoles 10B1 and 10B2 are positioned to cover the lower surfaces of the medial first core portion 20A1 and the lateral first core portion 20A2, respectively. These pair of lower midsoles 10B1 and 10B2 cover only the lower surfaces of the medial first core portion 20A1 and the lateral first core portion 20A2, respectively, and are not joined to the upper midsole 10A.

[0168] As shown in Figures 37 and 39, the front outsole 30A1 is positioned to cover only the lower surface 10b1 of the upper midsole 10A on the side of the recess 11a, and is joined to that part of the upper midsole 10A, for example by adhesive. The front outsoles 30A2 and 30A3 are positioned to cover only the lower surfaces 10b2 of the pair of lower midsoles 10B1 and 10B2, respectively, and are joined to that part of the pair of lower midsoles 10B1 and 10B2, for example by adhesive. The rear outsole 30B is positioned to cover only the lower surface 10b1 of the upper midsole 10A on the side of the recess 11a, and is joined to that part of the upper midsole 10A, for example by adhesive.

[0169] The upper midsole 10A of the portion that holds the medial foot side first core portion 20A1 and the lateral foot side first core portion 20A2 has a generally layered shape, and as described above, both the medial foot side first core portion 20A1 and the lateral foot side first core portion 20A2 have a flattened, roughly ball-shaped form. Therefore, both the medial foot side first core portion 20A1 and the lateral foot side first core portion 20A2 have a first enlarged portion 21a and a second enlarged portion 21b, and their circumferential surfaces are configured as unrestrained surfaces that are open and not covered by other members.

[0170] Therefore, even when using the shoe 1G and sole 2G according to the embodiment described above, effects similar to those described in Embodiment 1 above can be obtained, and higher cushioning and rebound performance can be obtained than in the conventional design.

[0171] In this embodiment, as described above, the pair of lower midsoles 10B1 and 10B2 are not joined to the upper midsole 10A, but rather cover only the lower surfaces of the medial first core portion 20A1 and the lateral first core portion 20A2, respectively. This configuration increases the mobility of the pair of lower midsoles 10B1 and 10B2, and consequently, the medial first core portion 20A1 and the lateral first core portion 20A2 to which they are fixed. Therefore, by adopting the configuration of this embodiment, it is possible to obtain a sole and a shoe equipped with it that is particularly suitable for walking or running on rough terrain with significant unevenness and undulations.

[0172] <Embodiment 8> Figure 40 is a schematic side view of the sole according to Embodiment 8, viewed from the outer foot side, and Figure 41 is a schematic perspective view of the sole shown in Figure 40. Figure 42 is a schematic cross-sectional view along the line XLII-XLII shown in Figure 40. The shoe 1H according to this embodiment and the sole 2H provided therein will be described below with reference to Figures 40 to 42. The upper (not shown) provided by the shoe 1H according to this embodiment is the same as the upper 3 provided by the shoe 1A according to Embodiment 1 described above.

[0173] As shown in Figures 40 to 42, the sole 2H according to this embodiment differs from the sole 2A according to Embodiment 1 described above in the configuration of the midsole 10 and the core portion 20, and also differs in that it does not have an outsole 30 (see Figure 1, etc.). More specifically, in the sole 2H according to this embodiment, the midsole 10 includes an upper midsole 10A and a lower midsole 10B, and the core portion 20 is composed of a single member sandwiched between these upper midsole 10A and lower midsole 10B.

[0174] For ease of understanding, in Figures 40 and 41, the midsole 10 is shown in a lighter color, and the core portion 20 is shown in a darker color. In this embodiment, the sole 2H does not have an outsole, but this may be provided separately.

[0175] The upper midsole 10A includes an upper surface 10a1 and a lower surface 10b1, of which the upper surface 10a1 defines the support surface 2a of the sole 2H. The lower midsole 10B includes an upper surface 10a2 and a lower surface 10b2, of which the lower surface 10b2 defines the contact surface 2b of the sole 2H. The medial and lateral portions of the lower midsole 10B are provided with slit-shaped holes extending along the front-to-back direction.

[0176] The core portion 20 is configured in a flat, roughly ball shape and is positioned to extend roughly from the medial edge to the lateral edge of the sole 2H along the left-right direction, and from the front end of the forefoot portion R1 to the rear end of the rearfoot portion R3 along the front-back direction. The lower surface 10b1 of the upper midsole 10A is provided with a recess 11a that corresponds to the shape of the upper surface of the core portion 20, and the upper surface 10a2 of the lower midsole 10B is provided with a recess 11b that corresponds to the shape of the lower surface of the core portion 20. As a result, the core portion 20 is sandwiched and held by the upper midsole 10A and the lower midsole 10B, and is positioned over almost the entire area of ​​the sole 2H, excluding the outer peripheral edge when viewed in plan.

[0177] The upper midsole 10A and lower midsole 10B that hold the core portion 20 have a generally layered shape, and as described above, the core portion 20 has a flattened, roughly ball-shaped form. Therefore, the core portion 20 has a first enlarged portion 21a and a second enlarged portion 21b, and their circumferential surfaces are configured as unrestrained surfaces that are not covered by other members.

[0178] Therefore, even when using the shoe 1H and sole 2H provided therein according to the embodiment described above, effects similar to those described in Embodiment 1 above can be obtained, and higher cushioning and rebound performance can be obtained than in the conventional design.

[0179] Furthermore, in this embodiment, the core portion 20 is also positioned in the portion of the sole 2H configured to support the heel of the wearer's foot. Therefore, with this configuration, the cushioning effect on the heel of the wearer's foot, which is the part that receives a relatively large load in reaction force upon landing, is improved, and a sole with even greater cushioning properties and a shoe equipped therewith can be obtained.

[0180] <Embodiment 9> Figure 43 is a schematic side view of the sole according to Embodiment 9, viewed from the outer foot side, and Figure 44 is a schematic bottom view of the sole shown in Figure 43. Hereinafter, the shoe 1I according to this embodiment and the sole 2I provided therewith will be described with reference to Figures 43 and 44. The upper (not shown) provided by the shoe 1I according to this embodiment is the same as the upper 3 provided by the shoe 1A according to Embodiment 1 described above.

[0181] As shown in Figures 43 and 44, the sole 2I according to this embodiment differs from the sole 2A according to Embodiment 1 described above in the configuration of the midsole 10 and the core portion 20, and also differs in that it does not have an outsole 30 (see Figure 1, etc.). More specifically, in the sole 2I according to this embodiment, the midsole 10 includes an upper midsole 10A and a pair of lower midsoles 10B1, 10B2, and the core portion 20 includes medial foot core group 20E1~20E4 and lateral foot core group 20F1~20F4.

[0182] For ease of understanding, in Figures 43 and 44, the midsole 10 is shown in a lighter color, and the core portion 20 is shown in a darker color. In this embodiment, the sole 2I does not have an outsole, but one may be provided separately.

[0183] The upper midsole 10A includes an upper surface 10a1 and a lower surface 10b1, of which the upper surface 10a1 defines the support surface 2a of the sole 2I. Furthermore, the lower surface 10b1 of the upper midsole 10A is provided with a recess 11a extending from the front end of the forefoot R1 to the rear end of the rearfoot R3.

[0184] The lower midsole 10B1 is located on the medial side of the sole 2I and extends along the anterior-posterior direction. The lower midsole 10B2 is located on the lateral side of the sole 2I and extends along the anterior-posterior direction. Each of the pair of lower midsoles 10B1 and 10B2 includes an upper surface 10a2 and a lower surface 10b2, of which the lower surface 10b2 defines the support surface 2a of the sole 2I. Furthermore, the upper surface 10a2 of the pair of lower midsoles 10B1 and 10B2 is provided with a recess 11b extending from the anterior end of the forefoot R1 to the posterior end of the rearfoot R3.

[0185] The medial core groups 20E1 to 20E4 are all configured in a flattened, roughly ball shape, and each of them is held in place by being sandwiched between the medial portion of the upper midsole 10A and the lower midsole 10B1 while positioned in the aforementioned recesses 11a and 11b. More specifically, the medial core groups 20E1 to 20E4 are positioned along the front-to-back direction on the medial portion of the sole 2I, and their size and orientation are appropriately adjusted.

[0186] The outer foot core groups 20F1 to 20F4 are all constructed in a flattened, roughly ball shape, and each of them is held in place by being sandwiched between the outer foot portion of the upper midsole 10A and the lower midsole 10B2 while positioned in the aforementioned recesses 11a and 11b. More specifically, the outer foot core groups 20F1 to 20F4 are positioned along the front-to-back direction on the outer foot portion of the sole 2I, and their size and orientation are appropriately adjusted.

[0187] The upper midsole 10A and lower midsoles 10B1, 10B2 of the portion that holds the medial foot core group 20E1~20E4 and the lateral foot core group 20F1~20F4 generally have a layered shape, and as described above, each of the medial foot core group 20E1~20E4 and the lateral foot core group 20F1~20F4 has a flattened, roughly ball-shaped form. Therefore, each of the medial foot core group 20E1~20E4 and the lateral foot core group 20F1~20F4 has a first enlarged portion 21a and a second enlarged portion 21b, and their circumferential surfaces are configured as unrestrained surfaces that are open and not covered by other members.

[0188] Therefore, even when using the shoe 1I and sole 2I according to the embodiment described above, effects similar to those described in Embodiment 1 can be obtained, and higher cushioning and rebound performance can be obtained than in the conventional design.

[0189] <Summary of disclosures in Embodiments 1 to 9 and their variations> The characteristic configurations disclosed in the embodiments 1 to 9 described above and their modified forms can be summarized as follows.

[0190] [Note 1] A sole having a thickness direction perpendicular to both the front-to-back direction, which is the direction that matches the length of the wearer's foot, and the left-to-right direction, which is the direction that matches the width of the wearer's foot, and having an upper surface configured as a support surface that supports the sole of the wearer's foot, and a lower surface configured as a contact surface, It consists of a foam material, a layered first base portion with the vertical direction as the thickness direction, The first base portion is located on the contact surface side when viewed from the first base portion, and comprises a core portion made of a foam material with lower hardness than the foam material constituting the first base portion. The core portion described above has at least an enlarged portion whose cross-sectional area increases as it moves along the axial direction from either the support surface side or the ground surface side, when the vertical direction is considered as the axial direction. A sole in which at least a portion of the circumferential surface of the enlarged portion is configured as an open, unrestrained surface that is not covered by other members.

[0191] By adopting the configuration described in Appendix 1 above, when the sole is compressed in the vertical direction, the core portion deforms easily. As a result, the amount of deformation due to compression deformation of the sole and the amount of recovery upon unloading are increased in the area where the core portion is located and in its vicinity. Therefore, a sole with unprecedented cushioning and rebound properties can be achieved.

[0192] [Note 2] The sole as described in Appendix 1, wherein the core portion includes, as the enlarged portion, a first enlarged portion whose cross-sectional area increases as it moves along the axial direction from the support surface side to the ground surface side, and a second enlarged portion whose cross-sectional area increases as it moves along the axial direction from the ground surface side to the support surface side.

[0193] By adopting the configuration described in Appendix 2 above, the acceleration of the deformation of the core portion described above can be easily achieved with a simple configuration.

[0194] [Note 3] The sole as described in Appendix 2, wherein the core portion has a ball-like shape with the first enlarged portion on its upper part and the second enlarged portion on its lower part.

[0195] By adopting the configuration described in Appendix 3 above, the deformation of the core portion described above can be maximized with a simple configuration, resulting in a sole with high cushioning and rebound properties.

[0196] [Note 4] The sole according to any one of the appendices 1 to 3, wherein the above-mentioned unrestrained surfaces are located on both sides of the core portion in the left-right direction.

[0197] By adopting the configuration described in Appendix 4 above, the acceleration of the deformation of the core portion described above can be easily achieved with a simple configuration.

[0198] [Note 5] The sole according to any one of the appendices 1 to 3, wherein the above-mentioned unrestrained surfaces are located on both sides of the core portion in the above-mentioned front-to-back direction.

[0199] By adopting the configuration described in Appendix 5 above, the acceleration of the deformation of the core portion described above can be easily achieved with a simple configuration.

[0200] [Note 6] The sole according to any one of the appendices 1 to 3, wherein the above-mentioned unrestrained surface is located around the entire circumference of the core portion.

[0201] By adopting the configuration described in Appendix 6 above, the acceleration of the deformation of the core portion described above can be maximized, resulting in a sole with high cushioning and rebound properties.

[0202] [Note 7] The sole according to any one of the appendices 1 to 6, wherein a void is provided inside the sole so as to face the core portion, and the circumferential surface of the core portion in the portion facing the void is configured as the unrestrained surface.

[0203] By adopting the configuration described in Appendix 7 above, the deformation of the core portion described above can be maximized, resulting in a sole with high cushioning and rebound properties.

[0204] [Note 8] The first high-hardness plate-shaped part is further made of a material with higher hardness than the foam material constituting the first base part and the core part described above, The first high-hardness portion is disposed between the first base portion and the core portion. The sole according to any one of the appendices 1 to 7, wherein the upper end of the core portion is fixed to the first high-hardness portion.

[0205] By adopting the configuration described in Appendix 8 above, it becomes possible to obtain not only the rebound properties obtained by providing a core, but also the rebound properties obtained by providing a plate-shaped high-hardness section, resulting in a sole with even greater rebound properties.

[0206] [Note 9] The above-mentioned core portion is located on the contact surface side and further comprises a layered second base portion with the vertical direction as the thickness direction, The sole according to any one of the appendices 1 to 7, wherein the second base portion is made of a foam material with higher hardness than the foam material constituting the core portion.

[0207] Even when the configuration described in Appendix 9 above is adopted, the core portion will easily deform when the sole is compressed in the vertical direction. As a result, the amount of deformation due to compression deformation of the sole and the amount of recovery upon unloading will be large in the area where the core portion is located and in its vicinity. Therefore, it is possible to create a sole with unprecedented cushioning and rebound properties.

[0208] [Note 10] The first high-hardness plate-shaped part is further made of a material with higher hardness than the foam material constituting the first base part and the core part described above, The first high-hardness portion is disposed between the first base portion and the core portion. The sole as described in Appendix 9, wherein the upper end of the core portion is fixed to the first high-hardness portion.

[0209] By adopting the configuration described in Appendix 10 above, it becomes possible to obtain not only the rebound properties obtained by providing a core, but also the rebound properties obtained by providing a plate-shaped high-hardness section, resulting in a sole with even greater rebound properties.

[0210] [Note 11] The system further comprises a plate-shaped second high-hardness portion made of a material with higher hardness than the foam material constituting the core portion and the second base portion, The above-mentioned second high-hardness portion is disposed between the above-mentioned core portion and the above-mentioned second base portion. The sole as described in Appendix 9, wherein the lower end of the core portion is fixed to the second high-hardness portion.

[0211] By adopting the configuration described in Appendix 11 above, it becomes possible to obtain not only the rebound properties obtained by providing a core, but also the rebound properties obtained by providing a plate-shaped high-hardness section, resulting in a sole with even greater rebound properties.

[0212] [Note 12] A plate-shaped first high-hardness portion made of a material with higher hardness than the foam material constituting the first base portion and the core portion, The system further comprises a plate-shaped second high-hardness portion made of a material with higher hardness than the foam material constituting the core portion and the second base portion, The first high-hardness portion is disposed between the first base portion and the core portion. The above-mentioned second high-hardness portion is disposed between the above-mentioned core portion and the above-mentioned second base portion. The upper end of the core portion is fixed to the first high-hardness portion. The sole as described in Appendix 9, wherein the lower end of the core portion is fixed to the second high-hardness portion.

[0213] By adopting the configuration described in Appendix 12 above, it becomes possible to obtain not only the rebound properties obtained by providing a core, but also the rebound properties obtained by providing a plate-shaped high-hardness section, resulting in a sole with even greater rebound properties.

[0214] [Note 13] It is made of a material with higher hardness than the foam material that constitutes the core portion, and further comprises an outsole that constitutes the contact surface. The sole according to any one of the appendices 1 to 8, wherein the outsole is fixed to the core so as to cover the lower end of the core.

[0215] Even when the configuration described in Appendix 13 above is adopted, the core portion will easily deform when the sole is compressed in the vertical direction. As a result, the amount of deformation due to compression deformation of the sole and the amount of recovery upon unloading will be large in the area where the core portion is located and in its vicinity. Therefore, it is possible to create a sole with unprecedented cushioning and rebound properties.

[0216] [Note 14] The sole according to any one of the appendices 1 to 13, wherein the core portion is located in the part of the sole configured to support the MP joint of the wearer's foot.

[0217] By adopting the configuration described in Appendix 14 above, it becomes possible to appropriately apply the high rebound force generated by the sole to the MP joint of the wearer's foot, which is the part that strongly pushes off the ground when kicking off, resulting in a sole with improved forward propulsion.

[0218] [Note 15] The sole according to any one of the appendices 1 to 13, wherein the core portion is located in the part of the sole configured to support the toes of the wearer's foot.

[0219] By adopting the configuration described in Appendix 15 above, it becomes possible to appropriately apply the high rebound force generated by the sole to the toes of the wearer's foot, which is the part that strongly pushes off the ground when kicking off, resulting in a sole that improves forward propulsion.

[0220] [Note 16] The sole according to any one of the appendices 1 to 13, wherein the core portion is located in the part of the sole configured to support the heel of the wearer's foot.

[0221] By adopting the configuration described in Appendix 16 above, the cushioning effect on the heel of the wearer's foot, which is the part that receives a relatively large load in reaction force upon landing, is improved, and the cushioning effect of the sole as a whole can be further enhanced.

[0222] [Note 17] The above core section comprises multiple units, The sole according to any one of the appendices 1 to 16, wherein the above-mentioned multiple core parts are arranged in a line along a direction intersecting the above-mentioned vertical direction.

[0223] Even when the configuration described in Appendix 17 above is adopted, when the sole is compressed in the vertical direction, the multiple core parts will easily deform. As a result, the amount of deformation due to compression deformation of the sole and the amount of recovery when unloaded will be large in the region where these multiple core parts are located and in their vicinity. Therefore, it is possible to create a sole with unprecedented cushioning and rebound properties.

[0224] [Note 18] The sole as described in Appendix 17, wherein the above-mentioned multiple core parts include at least two core parts connected to each other.

[0225] By adopting the configuration described in Appendix 18 above, the number of parts is reduced, improving ease of assembly, and the simplified structure also improves durability.

[0226] [Note 19] The above-mentioned core portion includes the first core portion, the second core portion and the third core portion as the plurality of core portions, The first core portion described above is positioned in the part of the sole that is configured to support the MP joint of the wearer's foot. The second core portion described above is positioned in the part of the sole that is configured to support the medial side of the toe area of ​​the wearer's foot. The third core portion described above is positioned in the part of the sole that is configured to support the outer foot portion of the toe area of ​​the wearer's foot. The first core unit and the second core unit are connected. The sole described in Appendix 18, wherein the first core portion and the third core portion are connected.

[0227] By adopting the configuration described in Appendix 19 above, the high rebound force generated by the sole can be appropriately applied to the MP joint and toe area of ​​the wearer's foot, which are the parts that strongly push off the ground during push-off. This not only improves the forward propulsion of the sole, but also improves ease of assembly by reducing the number of parts, and improves durability by simplifying the structure.

[0228] [Note 20] The sole described in any of the notes 1 to 19, A shoe featuring an upper positioned above the sole.

[0229] By adopting the configuration described in Appendix 20 above, when the sole is compressed in the vertical direction, the core portion deforms easily. As a result, the amount of deformation due to compression deformation of the sole and the amount of recovery upon unloading are increased in the area where the core portion is located and in its vicinity. Therefore, it is possible to create a shoe with a sole that has unprecedented cushioning and rebound properties.

[0230] <Other forms, etc.> The number, shape, size, and position of each part disclosed in the embodiments and their variations described above are not limited to those disclosed and can be modified in various ways. For example, the number, shape, size, and position of the core parts can be changed as appropriate and are not limited to those disclosed in the embodiments and their variations described above.

[0231] In the embodiments and their variations described above, shoes with an upper equipped with a tongue and shoelaces were used as examples, but the upper configuration is not limited to this. In other words, various configurations can be used for the upper, and for example, shoes with a sock-like upper made of knit material may also be used.

[0232] Furthermore, the characteristic configurations shown in the embodiments described above and their modified forms can be combined with each other without departing from the spirit of this disclosure.

[0233] Thus, the embodiments and their variations disclosed herein are illustrative in all respects and not restrictive. The technical scope of the present invention is defined by the claims and includes all modifications within the meaning and scope equivalent to the claims. [Explanation of symbols]

[0234] 1A~1I Shoe, 2A~2I, 2A1~2A6, 2B1, 2B2 Sole, 2a Support surface, 2b Contact surface, 3 Upper, 10 Midsole, 10A Upper midsole, 10B, 10B1, 10B2 Lower midsole, 10a, 10a1, 10a2 Top surface, 10b, 10b1, 10b2 Bottom surface, 11, 11a, 11b Recess, 12a, 12b Receiving part, 20 Core part, 20A First core part, 20A1 Medial first core part, 20A2 Outer first core part, 20B Second core part, 20C Third core part, 20D Fourth core part, 20E1~20E4 Medial core part group, 20F1~20F4 Outer core part group, 21a 1st enlargement section, 21b 2nd enlargement section, 30 outsole, 30A, 30A1~30A3 front outsole, 30B, 30B1, 30B2 rear outsole, 30a top surface, 30b bottom surface, 40A upper plate, 40B lower plate, 50 upper body, 51 tongue, 52 shoelaces, 100 ground, 200 foot, PB1 first boundary position, PB2 second boundary position, PF front end position, PR rear end position, R1 forefoot, R2 midfoot, R3 rearfoot, S gap, SC shoe center.

Claims

1. A sole having a thickness direction perpendicular to both the front-to-back direction, which is the direction that matches the length of the wearer's foot, and the left-to-right direction, which is the direction that matches the width of the wearer's foot, and having an upper surface configured as a support surface that supports the sole of the wearer's foot, and a lower surface configured as a contact surface, It consists of a foam material, a layered first base portion with the vertical direction as the thickness direction, The first base portion is located on the contact surface side when viewed from the first base portion and comprises a core portion made of a foam material with lower hardness than the foam material constituting the first base portion. The core portion has at least an enlarged portion whose cross-sectional area increases as it moves along the axial direction from one of the support surface side and the ground surface side to the other, when the vertical direction is considered as the axial direction. A sole in which at least a portion of the circumferential surface of the enlarged portion is configured as an open, unrestrained surface that is not covered by other members.

2. The sole according to claim 1, wherein the core portion includes, as the enlarged portion, a first enlarged portion whose cross-sectional area increases as it moves along the axial direction from the support surface side to the ground surface side, and a second enlarged portion whose cross-sectional area increases as it moves along the axial direction from the ground surface side to the support surface side.

3. The sole according to claim 2, wherein the core portion has a ball-like shape with the first enlarged portion at its upper part and the second enlarged portion at its lower part.

4. The sole according to claim 1, wherein the unrestrained surfaces are located on both sides of the core portion in the left-right direction.

5. The sole according to claim 1, wherein the unrestrained surfaces are located on both sides of the core portion in the front-rear direction.

6. The sole according to claim 1, wherein the unrestrained surface is located around the entire circumference of the core portion.

7. The sole according to claim 1, wherein a void is provided inside the sole so as to face the core, and the circumferential surface of the core in the portion facing the void is configured as the unrestrained surface.

8. The first high-hardness plate-shaped portion is further made of a material with higher hardness than the foam material constituting the first base portion and the core portion. The first high-hardness portion is disposed between the first base portion and the core portion. The sole according to claim 1, wherein the upper end of the core portion is fixed to the first high-hardness portion.

9. The second base portion is further provided, which is located on the contact surface side when viewed from the core portion and has a layered shape with the vertical direction as the thickness direction, The sole according to claim 1, wherein the second base portion is made of a foam material with higher hardness than the foam material constituting the core portion.

10. The first high-hardness plate-shaped portion is further made of a material with higher hardness than the foam material constituting the first base portion and the core portion. The first high-hardness portion is disposed between the first base portion and the core portion. The sole according to claim 9, wherein the upper end of the core portion is fixed to the first high-hardness portion.

11. The system further comprises a plate-shaped second high-hardness portion made of a material with higher hardness than the foam material constituting the core portion and the second base portion, The second high-hardness portion is disposed between the core portion and the second base portion. The sole according to claim 9, wherein the lower end of the core portion is fixed to the second high-hardness portion.

12. A plate-shaped first high-hardness portion made of a material with higher hardness than the foam material constituting the first base portion and the core portion, The system further comprises a plate-shaped second high-hardness portion made of a material with higher hardness than the foam material constituting the core portion and the second base portion, The first high-hardness portion is disposed between the first base portion and the core portion. The second high-hardness portion is disposed between the core portion and the second base portion. The upper end of the core portion is fixed to the first high-hardness portion. The sole according to claim 9, wherein the lower end of the core portion is fixed to the second high-hardness portion.

13. The core portion is made of a material with higher hardness than the foam material, and the outsole further comprises the contact surface. The sole according to claim 1, wherein the outsole is fixed to the core portion such that it covers the lower end of the core portion.

14. The sole according to claim 1, wherein the core portion is located in a portion of the sole configured to support the MP joint of the wearer's foot.

15. The sole according to claim 1, wherein the core portion is positioned in a portion of the sole configured to support the toes of the wearer's foot.

16. The sole according to claim 1, wherein the core portion is positioned in a portion of the sole configured to support the heel portion of the wearer's foot.

17. The system comprises multiple of the aforementioned core sections, The sole according to claim 1, wherein the plurality of core portions are arranged in a line along a direction intersecting the vertical direction.

18. The sole according to claim 17, wherein the plurality of core portions include at least two core portions connected to each other.

19. The core portion includes a first core portion, a second core portion, and a third core portion as the plurality of core portions, The first core portion is positioned in the part of the sole that is configured to support the MP joint of the wearer's foot. The second core portion is positioned in the part of the sole that is configured to support the medial portion of the toes of the wearer's foot. The third core portion is positioned in the part of the sole that is configured to support the outer foot portion of the toes of the wearer's foot. The first core portion and the second core portion are connected, The sole according to claim 18, wherein the first core portion and the third core portion are connected.

20. A sole according to any one of claims 1 to 19, A shoe comprising an upper located above the sole.

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