SOLE STRUCTURE AND SHOE INCLUDING THE SOLE STRUCTURE

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2024-057695 filed on Mar. 29, 2024, the entire disclosure of which is incorporated by reference herein.

BACKGROUND

The present disclosure relates to a sole structure and a shoe including the sole structure. A known sole structure applicable to a sports shoe for running and the like is disclosed in US Patent Application Publication No. 2023/0035794.

US Patent Application Publication No. 2023/0035794 discloses a sole structure (a sole 10) including a first cushion body (a first cushion body 30) and a second cushion body (a first cushion body 32). The first cushion body has a first hardness. The first cushion body is made of a first foam material. The second cushion body has a second hardness harder than the first hardness (that is, a hardness different from the first hardness). The second cushion body is made of a second foam material different from the first foam material. Part of the first cushion body and part of the second cushion body are stacked together in the top-bottom direction of the sole. The boundary portion of the overlap portion in which the first cushion body and the second cushion body overlap with each other in the top-bottom direction is exposed to the outside on the side surface located on the front side of the sole and the medial side of the sole (see FIGS. 3 and 6 of US Patent Application Publication No. 2023/0035794).

SUMMARY

As described above, the sole structure of US Patent Application Publication No. 2023/0035794 includes the first cushion body and the second cushion body each different in hardnesses and made of a different foam material. Thus, with the sole structure of US Patent Application Publication No. 2023/0035794, physical properties (cushioning properties and rigidity in particular) derived from each foam material can be given depending on each portion of the foot of a person who wears the shoe including the sole structure (hereinafter referred to as “the wearer”).

However, for the sole structure of US Patent Application Publication No. 2023/0035794, for example, when the wearer who is running puts his or her foot on a road surface (hereinafter referred to as “at the time of the foot being put on the ground”), the impact (external force) transmitted from the road surface is applied to the sole structure. This impact may significantly affect part of the sole structure in which the first cushion body and the second cushion body overlap with each other in the top-bottom direction (hereinafter referred to as “the overlap portion”) in particular. Specifically, for example, when the above impact acts on the boundary portion of the overlap portion, the overlap portion might be broken or the like from the boundary portion because stress tends to concentrate on the boundary portion of the overlap portion.

In view of the foregoing, the object of the present disclosure is to obtain physical properties required for a sole structure and to hold the sole structure stable.

In order to achieve the object, a first aspect of the present disclosure is directed to a sole structure. The sole structure includes a first midsole portion made of a first material; a second midsole portion which is made of a second material that is the same as or different from the first material, and at least part of which is stacked above or below the first midsole portion; and an exterior portion made of a third material having higher rigidity than the first material and the second material. A boundary portion of an overlap portion in which the first midsole portion and the second midsole portion overlap with each other in a top-bottom direction includes a first boundary portion defined by a line and located on each of a medial side and lateral side in side view and extending in a foot length direction. The exterior portion covers the first boundary portion from outside of the first midsole portion and the second midsole portion.

The sole structure of the first aspect includes the first midsole portion made of the first material and the second midsole portion made of the second material. Thus, physical properties (for example, cushioning properties, rebound properties, and impact absorbing properties) derived from the first material and the second material can be given depending on each portion of the foot of a person who wears the shoe including the sole structure (hereinafter referred to as “the wearer”).

On the other hand, for example, when the wearer who is running puts his or her foot on a road surface (at the time of the foot being put on the ground), the impact transmitted from the road surface is applied to the sole structure 1. This impact may significantly affect the overlap portion of the sole structure in particular. Specifically, for example, when the above impact acts on the boundary portion of the overlap portion, the overlap portion might be broken or the like from the boundary portion because stress tends to concentrate on the boundary portion of the overlap portion.

In order to solve the problem due to the overlap portion, the sole structure of the first aspect includes the exterior portion made of the third material having higher rigidity than the first material and the second material. The exterior portion covers the first boundary portion from outside of the first midsole portion and the second midsole portion. This configuration allows the exterior portion with relatively high rigidity to serve a function of reinforcing the first boundary portion and protecting the first boundary portion. Thus, even when the impact is applied to the sole structure at the time of the foot being put on the ground, the overlap portion is less likely to be broken or the like from the first boundary portion. That is, the sole structure can be held stable. In addition, the exterior portion made of the third material allows part of the sole structure in which the exterior portion is located to have higher rigidity (physical properties derived from the third material) than the first material and the second material.

Thus, in the first aspect, the sole structure can obtain the necessary physical properties, and the sole structure can be held stable.

A second aspect of the present disclosure is an embodiment of the first aspect. In the second aspect, the exterior portion includes a pair of side wall portions located on the medial side and lateral side, and each of the pair of side wall portions covers the first boundary portion in a lateral direction of the first midsole portion and the second midsole portion.

In the second aspect, the side wall portion serves a function of reinforcing the first boundary portion and protecting the first boundary portion. Thus, even when the impact is applied to the sole structure at the time of the foot being put on the ground, the overlap portion is less likely to be broken or the like from the first boundary portion. Thus, the sole structure can be held stable.

A third aspect of the present disclosure is an embodiment of the second aspect. In the third aspect, the boundary portion of the overlap portion further includes a second boundary portion defined by a line and located at a bottom of the first midsole portion and a bottom of the second midsole portion in bottom view. The exterior portion includes a bottom portion located below the first midsole portion and the second midsole portion. The bottom portion covers the second boundary portion from under the first midsole portion and the second midsole portion.

In the third aspect, the bottom portion of the exterior portion serves a function of reinforcing the second boundary portion and protecting the second boundary portion. Thus, even when the impact is applied to the sole structure at the time of the foot being put on the ground, the overlap portion is less likely to be broken or the like from the second boundary portion facing the road surface at the time of the foot being put on the ground. Thus, the sole structure can be held stable.

A fourth aspect of the present disclosure is an embodiment of the third aspect. In the fourth aspect, the bottom portion extends from a position of a midfoot portion to a position of a forefoot portion of a foot of a wearer in the sole structure.

In the fourth aspect, the bottom portion serves a function of increasing the rigidity of the lower side of the sole structure that ranges from the position of the midfoot portion to the position of the forefoot portion of the foot of the wearer. When the wearer is running, for example, this function of the bottom portion allows the weight shift to be more stabilized while the contact state of the foot of the wearer is shifting from the midfoot portion to the forefoot portion.

A fifth aspect of the present disclosure is an embodiment of the fourth aspect. In the fifth aspect, the bottom portion includes an upper surface on which a first reinforcement portion made of a fourth material having higher rigidity than the third material is provided.

In the fifth aspect, the first reinforcement portion brings a further increase in the rigidity of the lower side of the sole structure that ranges from the position of the midfoot portion to the position of the forefoot portion of the foot of the wearer. Thus, greater stepping force (so-called rocker function) can be produced particularly when the wearer steps off from the road surface using the forefoot portion of the foot.

A sixth aspect of the present disclosure is an embodiment of the first aspect. In the sixth aspect, the first material is a material having higher rebound properties than the second material. The second material is a material having higher impact absorbing properties than the first material and having lower rebound properties than the first material. The first midsole portion is located at part of the sole structure that corresponds to a position of at least a forefoot portion of a foot of a wearer. The second midsole portion is located at part of the sole structure that corresponds to a position of at least a rear foot portion of the foot of the wearer.

In the sixth aspect, the second midsole portion made of the second material is located at part of the sole structure that corresponds to the rear foot portion of the foot of the wearer. Thus, because of the physical properties (impact absorbing properties and low rebound properties) of the second material, higher impact absorbing properties can be achieved when the rear foot portion (a heel portion in particular) of the foot of the wearer is put on the road surface. On the other hand, the first midsole portion made of the first material is located at part of the sole structure that corresponds to the forefoot portion of the foot of the wearer. Thus, because of the physical properties (high rebound properties) of the first material, higher rebound properties can be achieved at a position of the forefoot portion of the foot when the forefoot portion of the foot of the wearer is put on the road surface. Further, the wearer can step forward using the forefoot portion of the foot at a greater acceleration.

A seventh aspect of the present disclosure is an embodiment of the sixth aspect. In the seventh aspect, the overlap portion is located at part of the sole structure that ranges from a position of a midfoot portion to a position of a front portion of the rear foot portion of the foot of the wearer.

In the seventh aspect, at part of the sole structure that ranges from the position of the midfoot portion to the position of the front portion of the rear foot portion of the foot of the wearer, the first midsole portion and the second midsole portion overlap with each other in the thickness direction of the sole structure. Thus, the part that ranges from the position of the midfoot portion to the position of the front portion of the rear foot portion of the foot of the wearer can exhibit the physical properties of both the first material and the second material. As a result, the contact state can be smoothly shifted from when the wearer starts putting the rear foot portion on the road surface to when the wearer steps off from the road surface using the forefoot portion.

An eighth aspect of the present disclosure is an embodiment of the seventh aspect. In the eighth aspect, the first boundary portion extends from a lower side to an upper side of the sole structure while extending from the position of the midfoot portion to the position of the front portion of the rear foot portion of the foot of the wearer in the sole structure.

In the eighth aspect, in the process from when the wearer starts putting the rear foot portion on the road surface to when the wearer steps off from the road surface using the forefoot portion, the physical properties of the first material and the second material can be gradually switched. That is, the contact state can be smoothly shifted from when the wearer starts putting the foot on the road surface to when the wearer steps off from the road surface.

Further, in the eighth aspect, similarly to the first aspect, the exterior portion covers the first boundary portion from outside of the first midsole portion and the second midsole portion. That is, the part of the sole structure that ranges from the position of the midfoot portion to the position of the front portion of the rear foot portion of the foot of the wearer is reinforced and protected by the exterior portion. As a result, when the wearer is running, the weight shift can be stabilized while the contact state of the foot of the wearer is shifting from the rear foot portion to the forefoot portion.

A ninth aspect of the present disclosure is an embodiment of the first aspect. In the ninth aspect, each of the first material and the second material is a material softer than the third material and having higher rebound properties than the third material. The first midsole portion is located at part of the sole structure that corresponds to a range from the forefoot portion to the front portion of the rear foot portion of the foot of the wearer. The second midsole portion is located at part of the sole structure that ranges from a position of a midfoot portion to a position of the rear foot portion of the foot of the wearer.

In the ninth aspect, because of the positional relationship between the first midsole portion and the second midsole portion, the common physical properties (softness and high rebound) of the first material and the second material can be obtained at part of the sole structure that ranges from the position of the forefoot portion to the position of the rear foot portion of the foot of the wearer.

Further, in the ninth aspect, similarly to the first aspect, the exterior portion covers the first boundary portion from outside of the first midsole portion and the second midsole portion. That is, in the ninth aspect, the part of the sole structure that ranges from the position of the midfoot portion to the position of the front portion of the rear foot portion of the foot of the wearer can be reinforced and protected. As a result, when the wearer is running, the weight shift can be stabilized while the contact state of the foot of the wearer is shifting from the rear foot portion to the forefoot portion.

A tenth aspect of the present disclosure is an embodiment of the first aspect. In the tenth aspect, the first material is a material having higher rigidity than the second material. The second material is a material softer than the first material and having higher rebound properties than the first material. The first midsole portion is located at part of the sole structure that ranges from a position of a forefoot portion to a position of the midfoot portion of the foot of the wearer. The second midsole portion is located at part of the sole structure that ranges from the position of the forefoot portion to the position of the rear foot portion of the foot of the wearer.

In the tenth aspect, the second midsole portion made of the second material is located at part of the sole structure that ranges from the position of the forefoot portion to the position of the rear foot portion of the foot of the wearer. Thus, higher cushioning properties and higher rebound properties can be achieved based on the physical properties (softness and high rebound) of the second material at part that ranges from the position of the forefoot portion to the position of the rear foot portion of the foot of the wearer. On the other hand, the first midsole portion made of the first material is located at part of the sole structure that ranges from the position of the forefoot portion to the position of the midfoot portion of the foot of the wearer. Thus, when the forefoot portion of the foot of the wearer is put on the road surface, greater stepping force (rocker function) can be produced based on the physical properties (rigidity) of the first material particularly when the wearer steps forward using the forefoot portion of the foot.

An eleventh aspect of the present disclosure is an embodiment of the tenth aspect. In the eleventh aspect, the overlap portion is located at part of the sole structure that ranges from a position of a forefoot portion to a position of the midfoot portion of the foot of the wearer. In the overlap portion, the first midsole portion is located below the second midsole portion.

In the eleventh aspect, at part of the sole structure that ranges from the position of the forefoot portion to the position of the midfoot portion of the foot of the wearer, the first midsole portion and the second midsole portion overlap with each other in the thickness direction of the sole structure. Thus, the part that ranges from the position of the forefoot portion to the position of the midfoot portion of the foot of the wearer can exhibit the physical properties of both the first material and the second material. Further, since, in the overlap portion, the first midsole portion is located below the second midsole portion, cushioning properties and rebound properties can be obtained while greater stepping force (rocker function) can be produced in the forward direction, at part that ranges from the position of the forefoot portion to the midfoot portion of the foot of the wearer.

A twelfth aspect of the present disclosure is an embodiment of the eleventh aspect. In the twelfth aspect, the first boundary portion extends from a lower side to an upper side of the sole structure while extending from the position of the midfoot portion to the position of the forefoot portion of the foot of the wearer in the sole structure. The sole structure further includes a second reinforcement portion made of a fourth material having higher rigidity than the third material. The second reinforcement portion is disposed at the first boundary portion and is stacked between the first midsole portion and the second midsole portion.

In the twelfth aspect, the second reinforcement portion brings a further increase in the rigidity of the position of the first boundary portion (the part of the sole structure that ranges from the position of the midfoot portion to the position of the forefoot portion of the foot of the wearer). Thus, greater stepping force (rocker function) can be produced particularly when the wearer steps off from the road surface using the forefoot portion of the foot.

A thirteenth aspect of the present disclosure is directed to a shoe including the sole structure of the first aspect.

In the thirteenth aspect, the shoe providing the same advantage as to those of the sole structure of the first aspect can be obtained.

As described above, in the present disclosure, the sole structure can obtain the necessary physical properties, and the sole structure can be held stable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a shoe including a sole structure according to an embodiment of the present disclosure as viewed from the lateral side.

FIG. 2 is a perspective view of the sole structure as viewed from above.

FIG. 3 is an exploded perspective view of a midsole and an exterior portion as viewed from above.

FIG. 4 is a plan view of the sole structure of FIG. 1 as viewed from above.

FIG. 5 is a bottom view of the sole structure of FIG. 1.

FIG. 6 is a side view of the sole structure of FIG. 1 as viewed from the medial side.

FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 4.

FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 4.

FIG. 9 corresponds to FIG. 1 and shows a shoe including a sole structure according to a second variation.

FIG. 10 corresponds to FIG. 1 and shows a shoe including a sole structure according to a third variation.

FIG. 11 corresponds to FIG. 1 and shows a shoe including a sole structure according to a fourth variation.

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described in detail with reference to the drawings. The following description of preferred embodiments is merely illustrative in nature and is not intended to limit the present disclosure, its application, or its use.

(Shoe)

FIG. 1 shows the whole of a shoe S including a sole structure 1 and an upper 2 for covering a foot of a wearer according to an embodiment of the present disclosure. The shoe S is suitable for running, for example. The shoe S is not limited to a shoe for running, and can be used as a shoe for various sports competitions.

(Sole Structure)

As shown in FIGS. 1 to 6, the sole structure 1 includes an outsole 10 and a midsole 20.

In the embodiment of the present disclosure, the sole structure 1 is shown for a left foot only. Although not shown, the sole structure for a right foot is symmetrical to the sole structure 1 for a left foot. In the following description, only the sole structure 1 for a left foot will be described, and the description of the sole structure for a right foot will be omitted. FIG. 1 also shows only the shoe S for a left foot.

In the following description, the terms “top” and “bottom” in the figures represent a positional relationship in the thickness direction (the top-bottom direction) of the sole structure 1. The terms “medial side” and “lateral side” in the figures represent a positional relationship of the sole structure 1 in the foot width direction. The terms “front” and “rear” in the figures represent a positional relationship of the sole structure 1 in the foot length direction.

Further, as shown in FIGS. 1 and 4 to 7, the range of the sole structure 1 that corresponds to a forefoot portion of a foot of a wearer is indicated by the reference character F; the range of the sole structure 1 that corresponds to a midfoot portion of a foot of a wearer is indicated by the reference character M; and the range of the sole structure 1 that corresponds to a rear foot portion of a foot of a wearer is indicated by the reference character F. In FIGS. 1 to 3, the reference characters F, M, H are not shown for the sake of simplicity of the figures.

(Outsole)

As shown in FIGS. 1 to 3 and 6, the outsole 10 is stacked below the midsole 20. The outsole 10 is made of a hard elastic material harder than the midsole 20.

Specifically, examples of the material for the outsole 10 include thermoplastic synthetic resins such as ethylene-vinyl acetate copolymer (EVA), thermosetting resins such as polyurethane (PU), rubber materials such as butadiene rubber and chloroprene rubber, and foam materials obtained by foaming of these materials. According to the durometer C or A, the hardness of the outsole 10 is preferably set to 50 A to 80 A (more preferably 60 A to 70 A), for example.

As shown in FIGS. 5 and 7, the outsole 10 includes a first outsole portion 11, a second outsole portion 12, and a third outsole portion 13.

The first outsole portion 11 is located at part of the sole structure 1 that corresponds to the forefoot portion F of the foot of the wearer. The first outsole portion 11 is attached to the lower surface of a first midsole portion 21 described later.

The second outsole portion 12 is located at part of the sole structure 1 that corresponds to the forefoot portion F of the foot of the wearer. The second outsole portion 12 is attached to an exterior portion 30 described later. Specifically, the second outsole portion 12 is attached to the lower surface of a bottom portion 32 described later.

The third outsole portion 13 is located at part of the sole structure 1 that corresponds to the rear foot portion H of the foot of the wearer. The third outsole portion 13 is attached to the lower surface of a second midsole portion 22 described later.

(Midsole)

As shown in FIGS. 1 to 3 and 6, the midsole 20 is stacked above the outsole 10. The upper 2 is attached to the midsole 20 (see FIG. 1).

As shown in FIGS. 1 to 8, the midsole 20 consists of the first midsole portion 21 and the second midsole portion 22. The first midsole portion 21 and the second midsole portion 22 partially overlap with each other in the top-bottom direction.

The upper surface of the first midsole portion 21 and the upper surface of the second midsole portion 22 constitute a foot sole support surface 23 for supporting a foot sole of the wearer. The foot sole support surface 23 may directly support the foot sole of the wearer, or may support the foot sole of the wearer via an insole (not shown).

(First Midsole Portion)

The first midsole portion 21 is made of a first material. The first material of this embodiment is a material having higher rebound properties than a second material described later. Examples of the first material include thermoplastic polyurethane (TPU) foam having the hardness of 40 C according to the Asker C scale.

As shown in FIGS. 4 to 6, the first midsole portion 21 is located at part of the sole structure 1 that ranges from the position of the forefoot portion F to the position of the front portion of the rear foot portion H of the foot of the wearer.

(Second Midsole Portion)

The second midsole portion 22 is made of the second material. In this embodiment, the second material is a material different from the first material. For example, the second material is a material having higher impact absorbing properties than the first material and having lower rebound properties than the first material. Specific examples of the second material include polyurethane (PU) foam having the hardness of 30 C according to the Asker C scale.

As shown in FIGS. 4 to 6, the second midsole portion 22 is located at part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the rear foot portion H of the foot of the wearer. As shown in FIG. 4, in a plan view, the upper surface of the second midsole portion 22 is located at part of the foot sole support surface 23 that corresponds to the rear foot portion H.

As shown in FIGS. 6 and 7, in this embodiment, part of the second midsole portion 22 is stacked below part of the first midsole portion 21. Specifically, a front part of the second midsole portion 22 is stacked below a rear part of the first midsole portion 21.

(Overlap Portion)

As shown in FIGS. 1 to 8, the sole structure 1 includes an overlap portion 24. The overlap portion 24 corresponds to a portion in which the first midsole portion 21 and the second midsole portion 22 overlap with each other in the top-bottom direction. FIG. 8 shows the components with a larger scale than FIGS. 4 to 7 for the sake of clarity.

In this embodiment, the overlap portion 24 is located at part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the front portion of the rear foot portion H of the foot of the wearer. In the overlap portion 24 of this embodiment, a front portion of the second midsole portion 22 is located below a rear portion of the first midsole portion 21. As shown in FIG. 4, in a plan view, the overlap portion 24 is located at part of the foot sole support surface 23 that corresponds to a front portion of the rear foot portion H of the foot of the wearer.

(First Boundary Portion)

As shown in FIGS. 1, 3, and 6, the overlap portion 24 serves as a boundary portion 25 defined by a line. The boundary portion 25 includes a first boundary portion 26 defined by a line in a side view. The first boundary portion 26 is located on each of the medial side and lateral side in a side view.

The first boundary portion 26 is located to cover part of the sole structure 1 that corresponds to the position of at least the midfoot portion M of the foot of the wearer. In this embodiment, the first boundary portion 26 is located at part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the front portion of the rear foot portion H of the foot of the wearer.

The first boundary portion 26 extends in the foot length direction. Specifically, the first boundary portion 26 of this embodiment extends from the lower side to the upper side of the sole structure 1 while extending from the midfoot portion M to the front portion of the rear foot portion H of the foot of the wearer in the sole structure 1.

(Second Boundary Portion)

As shown in FIG. 5, the boundary portion 25 of the overlap portion 24 includes a second boundary portion 27 defined by a line in bottom view. The second boundary portion 27 is located at a bottom of the first midsole portion 21 and a bottom of the second midsole portion 22 in bottom view.

The second boundary portion 27 is located at part of the sole structure 1 that corresponds to the midfoot portion M of the foot of the wearer in bottom view. Below the first midsole portion 21 and the second midsole portion 22, the second boundary portion 27 is contiguous with the first boundary portion 26.

(Exterior Portion)

As shown in FIGS. 1 to 8, the sole structure 1 includes the exterior portion 30. The exterior portion 30 is made of a third material having higher rigidity than the first material and the second material. Specific examples of the third material include ethylene-vinyl acetate copolymer (EVA) foam having the hardness of 60 C according to the Asker C scale.

The exterior portion 30 is located at part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the rear foot portion H of the foot of the wearer. The exterior portion 30 is attached to the first midsole portion 21 and the second midsole portion 22 with an adhesive, for example.

The embodiment of the present disclosure is characterized in that the exterior portion 30 covers the first boundary portions 26, 26 from outside of the first midsole portion 21 and the second midsole portion 22. The exterior portion 30 of this embodiment is configured so that the whole of the first boundary portions 26, 26 is not exposed to the outside (see FIGS. 1 and 6).

(Side Wall Portion)

As shown in FIGS. 3 to 5, the exterior portion 30 includes a pair of side wall portions 31, 31. The side wall portion 31 is located on each of the medial side and lateral side. The side wall portions 31 are integrated with a rear portion of the bottom portion 32 described later (see FIGS. 3 and 5). The side wall portion 31 extends obliquely upward from the bottom portion 32 while extending rearward from the rear portion of the bottom portion 32.

As shown in FIGS. 6 and 8, the side wall portion 31 on the medial side covers the first boundary portion 26 on the medial side in the lateral direction of the first midsole portion 21 and the second midsole portion 22. As shown in FIGS. 1 and 8, the side wall portion 31 on the lateral side covers the first boundary portion 26 on the lateral side in the lateral direction of the first midsole portion 21 and the second midsole portion 22.

(Bottom Portion)

As shown in FIGS. 3 and 5, the exterior portion 30 includes the bottom portion 32. The bottom portion 32 is located below the first midsole portion 21 and the second midsole portion 22. The bottom portion 32 is contiguous with the pair of side wall portions 31, 31.

As shown in FIGS. 3 and 7, the bottom portion 32 includes an upper surface on which a housing portion 33 is provided to house a first reinforcement portion 41 described later. The housing portion 33 is recessed downward from the upper surface of the bottom portion 32 and has a bottom.

As shown in FIG. 5, the bottom portion 32 extends from the position of the midfoot portion M to the position of the forefoot portion F of the foot of the wearer in the sole structure 1. The bottom portion 32 includes a toe portion tapered, in bottom view, from each of the medial side and lateral side to the substantially center in the foot width direction while extending from the position of the midfoot portion M to the position of the forefoot portion F.

As shown in FIGS. 5 and 7, the bottom portion 32 covers the second boundary portion 27 from the lower side of the first midsole portion 21 and the second midsole portion 22. Specifically, the bottom portion 32 includes a rear portion that overlaps with the second boundary portion 27 in the top-bottom direction (see FIG. 7).

(First Reinforcement Portion)

As shown in FIGS. 3 and 7, the bottom portion 32 includes an upper surface above which the first reinforcement portion 41 is provided. The first reinforcement portion 41 is housed in the housing portion 33 of the exterior portion 30. Specifically, while being housed in the housing portion 33, the first reinforcement portion 41 is stacked between the first midsole portion 21 and the bottom portion 32 of the exterior portion 30 (see FIG. 7). The first reinforcement portion 41 is formed in a substantially plate shape (see FIG. 3).

The first reinforcement portion 41 is made of a fourth material having higher rigidity than the third material. Specific examples of the fourth material include carbon fiber reinforced plastic (CFRP) and polyamide (PA).

Advantages of Embodiment

As described above, the sole structure 1 includes the first midsole portion 21 made of the first material and the second midsole portion 22 made of the second material. With this configuration, physical properties (for example, cushioning properties, rebound properties, and impact absorbing properties) derived from the first material and the second material can be given depending on each portion of the foot of the wearer.

On the other hand, for example, when the wearer who is running puts his or her foot on a road surface (hereinafter referred to as “at the time of the foot being put on the ground”), the impact transmitted from the road surface is applied to the sole structure 1. This impact may significantly affect the overlap portion 24 of the sole structure 1 in particular. Specifically, for example, when the above impact acts on the boundary portion 25 of the overlap portion 24, the overlap portion 24 might be broken or the like from the boundary portion 25 because stress tends to concentrate on the boundary portion 25 of the overlap portion 24.

In order to solve the problem due to the overlap portion 24, the sole structure 1 includes the exterior portion 30 made of the third material having higher rigidity than the first material and the second material. The exterior portion 30 covers the first boundary portion 26 from outside of the first midsole portion 21 and the second midsole portion 22. This configuration allows the exterior portion 30 with relatively high rigidity to serve a function of reinforcing the first boundary portion 26 and protecting the first boundary portion 26. Thus, even when the impact is applied to the sole structure 1 at the time of the foot being put on the ground, the overlap portion 24 is less likely to be broken or the like from the first boundary portion 26. That is, the sole structure 1 can be held stable. In addition, the exterior portion 30 made of the third material allows part of the sole structure 1 in which the exterior portion 30 is located to have higher rigidity (physical properties derived from the third material) than the first material and the second material.

Thus, in the embodiment of the present disclosure, the sole structure 1 can obtain the necessary physical properties, and the sole structure 1 can be held stable.

When the first material and the second material are used to form the first midsole portion 21 and the second midsole portion 22 by two-color molding, for example, the boundary portion 25 of the overlap portion 24 might be visually distorted in a wavy shape. If the boundary portion 25 distorted in this manner is exposed to the outside, the sole structure 1 and the shoe S might be less aesthetic. However, in the sole structure 1 according to the embodiment of the present disclosure, the exterior portion 30 covers the first boundary portion 26 from outside of the first midsole portion 21 and the second midsole portion 22 (that is, the exterior portion 30 prevents the first boundary portion 26 from being exposed to the outside). Thus, even if the boundary portion 25 of the overlap portion 24 is distorted, the sole structure 1 and the shoe S can keep themselves aesthetic.

The exterior portion 30 includes a pair of side wall portions 31, 31 located on the medial side and lateral side. The side wall portion 31 covers the first boundary portion 26 in the lateral direction of the first midsole portion 21 and the second midsole portion 22. This configuration allows the side wall portion 31 to serve a function of reinforcing the first boundary portion 26 and protecting the first boundary portion 26. Thus, even when the impact is applied to the sole structure 1 at the time of the foot being put on the ground, the overlap portion 24 is less likely to be broken or the like from the first boundary portion 26. Thus, the sole structure 1 can be held stable.

The bottom portion 32 of the exterior portion 30 covers the second boundary portion 27 from under the first midsole portion 21 and the second midsole portion 22. This configuration allows the bottom portion 32 to serve a function of reinforcing the second boundary portion 27 and protecting the second boundary portion 27. Thus, even when the impact is applied to the sole structure 1 at the time of the foot being put on the ground, the overlap portion 24 is less likely to be broken or the like from the second boundary portion 27 facing the road surface at the time of the foot being put on the ground. Thus, the sole structure 1 can be held stable.

The bottom portion 32 extends from the position of the midfoot portion M to the position of the forefoot portion F of the foot of the wearer in the sole structure 1. This configuration allows the bottom portion 32 to serve a function of increasing the rigidity of the lower side of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the forefoot portion F of the foot of the wearer. When the wearer is running, for example, this function allows the weight shift to be more stabilized while the contact state of the foot of the wearer is shifting from the midfoot portion M to the forefoot portion F.

The bottom portion 32 includes an upper surface on which the first reinforcement portion 41 made of the fourth material having higher rigidity than the third material is provided. This first reinforcement portion 41 brings a further increase in the rigidity of the lower side of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the forefoot portion F of the foot of the wearer. Thus, greater stepping force (rocker function) can be produced particularly when the wearer steps off from the road surface using the forefoot portion F of the foot.

In this embodiment, the first material is a material having higher rebound properties than the second material. The second material is a material having higher impact absorbing properties than the first material and having lower rebound properties than the first material. In this embodiment, the second midsole portion 22 made of the second material is located at part of the sole structure 1 that corresponds to the rear foot portion H of the foot of the wearer. Thus, because of the physical properties (impact absorbing properties and low rebound properties) of the second material, higher impact absorbing properties can be achieved when the rear foot portion H (a heel portion in particular) of the foot of the wearer is put on the road surface. On the other hand, the first midsole portion 21 made of the first material is located at part of the sole structure 1 that corresponds to the forefoot portion F of the foot of the wearer. Thus, because of the physical properties (high rebound properties) of the first material, higher rebound properties can be achieved at a position of the forefoot portion F of the foot when the forefoot portion F of the foot of the wearer is put on the road surface. Further, the wearer can step forward using the forefoot portion F of the foot at a greater acceleration.

In this embodiment, the overlap portion 24 is located at part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the front portion of the rear foot portion H of the foot of the wearer. That is, at part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the front portion of the rear foot portion H of the foot of the wearer, the first midsole portion 21 and the second midsole portion 22 overlap with each other in the thickness direction of the sole structure 1. Thus, the part that ranges from the position of the midfoot portion M to the position of the front portion of the rear foot portion H of the foot of the wearer can exhibit the physical properties of both the first material and the second material. As a result, the contact state can be smoothly shifted from when the wearer starts putting the rear foot portion H on the road surface to when the wearer steps off from the road surface using the forefoot portion F.

The first boundary portion 26 extends from the lower side to the upper side of the sole structure 1 while extending from the position of the midfoot portion M to the position of the front portion of the rear foot portion H of the foot of the wearer in the sole structure 1. Thus, in the process from when the wearer starts putting the rear foot portion H on the road surface to when the wearer steps off from the road surface using the forefoot portion F, the physical properties of the first material and the second material can be gradually switched. That is, the contact state can be smoothly shifted from when the wearer starts putting the foot on the road surface to when the wearer steps off from the road surface. Further, in this embodiment, the part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the front portion of the rear foot portion H of the foot of the wearer is reinforced and protected by the exterior portion 30. As a result, when the wearer is running, the weight shift can be stabilized while the contact state of the foot of the wearer is shifting from the rear foot portion H to the forefoot portion F.

First Variation of Embodiment

In the above embodiment, the second material is a material different from the first material, but the configuration is not limited thereto. For example, the second material may be the same material as the first material.

Specifically, as a first variation of the embodiment, each of the first material and the second material may be a material softer than the third material and having higher rebound properties than the third material. Specific examples of the first material and the second material of this variation include polyester-based thermoplastic elastomer (TPEE) foam having the hardness of 40 C according to the Asker C scale.

In the first variation, similarly to the embodiment, the first midsole portion 21 is located at part of the sole structure 1 that ranges from the position of the forefoot portion F to the position of the front portion of the rear foot portion H of the foot of the wearer, whereas the second midsole portion 22 is located at part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the rear foot portion H of the foot of the wearer.

In this variation, because of the positional relationship between the first midsole portion 21 and the second midsole portion 22, the common physical properties (softness and high rebound) of the first material and the second material can be obtained at part of the sole structure 1 that ranges from the position of the forefoot portion F to the position of the rear foot portion H of the foot of the wearer.

Further, in this variation, the part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the front portion of the rear foot portion H of the foot of the wearer is reinforced and protected by the exterior portion 30. As a result, when the wearer is running, the weight shift can be stabilized while the contact state of the foot of the wearer is shifting from the rear foot portion H to the forefoot portion F.

Second Variation of Embodiment

In the embodiment, the overlap portion 24 is located at part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the front portion of the rear foot portion H of the foot of the wearer, but the configuration is not limited thereto. For example, a second variation may be configured as shown in FIG. 9. In this variation, the boundary portion 25 of the overlap portion 24 does not include the second boundary portion 27 described in the embodiment.

As shown in FIG. 9, the overlap portion 24 is located at the whole part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the rear foot portion H of the foot of the wearer. That is, the first midsole portion 21 and the second midsole portion 22 overlap with each other in the top-bottom direction at the whole part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the rear foot portion H of the foot of the wearer. Thus, the physical properties of both the first material and the second material can be given to the whole part that ranges from the position of the midfoot portion M to the position of the front portion of the rear foot portion H of the foot of the wearer.

Further, unlike the embodiment, the first boundary portion 26 of this variation may extend from the position of the midfoot portion M to the position of the rear portion of the rear foot portion H over the position of the front portion of the rear foot portion H of the foot of the wearer in the sole structure 1. Further, the exterior portion 30 of this variation may be located in side view at part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the rear portion of the rear foot portion H of the foot of the wearer. Thus, the rigidity of the exterior portion 30 made of the third material can be obtained at part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the rear foot portion H of the foot of the wearer.

Further, in the exterior portion 30 of this variation, the outer line of the peripheral edge portion located on each of the upper side and the lower side of the side wall portion 31 is formed in a curved shape that is wavy with respect to the extending direction of the first boundary portion 26. The side wall portion 31 with this shape has higher rigidity.

Even if, like this variation, the rear portion of the first boundary portion 26 (the rear portion of the first boundary portion 26 located close to the rear end of the sole structure 1 as shown in FIG. 9) is exposed to the outside, the advantage of the exterior portion 30 (the side wall portion 31) described in the embodiment can be fully achieved as long as the exterior portion 30 (the side wall portion 31) covers most of the first boundary portion 26.

Third Variation of Embodiment

As another variation of the embodiment, the positional relationship between the first midsole portion 21 and the second midsole portion 22 described as the second variation (see FIG. 9) may be reversed in the top-bottom direction as a third variation shown in FIG. 10. Specifically, as shown in FIG. 10, the whole of the second midsole portion 22 may be located above the first midsole portion 21.

Fourth Variation of Embodiment

As a fourth variation of the embodiment above, the configurations described in the embodiment: the physical properties of the first material and the second material; the positional relationship between the first midsole portion 21 and the second midsole portion 22; the position and area of the overlap portion 24; and the position of the exterior portion 30, may be changed to the following as shown in FIG. 11.

Specifically, in this variation, the first material is a material having higher rigidity than the second material. Specific examples of the first material of this variation include ethylene-vinyl acetate copolymer (EVA) foam having the hardness of 50 C according to the Asker C scale. The first material of this variation is a material having lower rigidity than the third material.

The second material is a material softer than the first material and having higher rebound properties than the first material. Specific examples of the second material of this variation include polyether block amide (PEBA) foam having the hardness of 40 C according to the Asker C scale.

As shown in FIG. 11, the first midsole portion 21 is located at part of the sole structure 1 that ranges from the position of the forefoot portion F to the position of the midfoot portion M of the foot of the wearer. On the other hand, the second midsole portion 22 is located at part of the sole structure 1 that ranges from the position of the forefoot portion F to the position of the rear foot portion H of the foot of the wearer.

In the sole structure 1 of this variation, the second midsole portion 22 can provide higher cushioning properties and higher rebound properties based on the physical properties (softness and high rebound) of the second material at part that ranges from the position of the forefoot portion F to the position of the rear foot portion H of the foot of the wearer. On the other hand, when the forefoot portion F of the foot of the wearer is put on the road surface, the first midsole portion 21 enables greater stepping force (rocker function) to be produced based on the physical properties (rigidity) of the first material particularly when the wearer steps forward using the forefoot portion F of the foot.

As shown in FIG. 11, the overlap portion 24 is located at part of the sole structure 1 that ranges from the position of the forefoot portion F to the position of the midfoot portion M of the foot of the wearer. In the overlap portion 24, the first midsole portion 21 is located below the second midsole portion 22. That is, at part of the sole structure 1 that ranges from the position of the forefoot portion F to the position of the midfoot portion M of the foot of the wearer, the first midsole portion 21 and the second midsole portion 22 overlap with each other in the thickness direction of the sole structure 1.

Thus, the part that ranges from the position of the forefoot portion F to the position of the midfoot portion M of the foot of the wearer can exhibit the physical properties of both the first material and the second material. Further, since, in the overlap portion 24, the first midsole portion 21 is located below the second midsole portion 22, cushioning properties and rebound properties can be obtained while greater stepping force (rocker function) can be produced in the forward direction, at part that ranges from the position of the forefoot portion F to the midfoot portion M of the foot of the wearer.

Further, as shown in FIG. 11, the first boundary portion 26 extends from the lower side to the upper side of the sole structure 1 while extending from the position of the midfoot portion M to the position of the forefoot portion F of the foot of the wearer in the sole structure 1.

The sole structure 1 of the fourth variation includes a second reinforcement portion 42 made of the fourth material having higher rigidity than the third material. The second reinforcement portion 42 is disposed at the first boundary portion 26 and is stacked between the first midsole portion 21 and the second midsole portion 22. Similarly to the embodiment, specific examples of the fourth material of this variation include carbon fiber reinforced plastic (CFRP) and polyamide (PA).

This second reinforcement portion 42 brings a further increase in the rigidity of the position of the first boundary portion 26 (the part of the sole structure 1 that ranges from the position of the midfoot portion M to the position of the forefoot portion F of the foot of the wearer). As a result, greater stepping force (rocker function) can be produced particularly when the wearer steps off from the road surface using the forefoot portion F of the foot.

OTHER EMBODIMENTS

In the embodiment, the configuration with the first reinforcement portion 41 is shown, but the configuration is not limited thereto. That is, in the embodiment, the first reinforcement portion 41 may be omitted.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications can be made within the scope of the present disclosure.

The present disclosure is industrially applicable to a sole structure for a running shoe and a shoe including the sole structure.