Sole Structure and Shoe Including the Sole Structure

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.

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) including a first cushion body (a first cushion body) and a second cushion body (a first cushion body). 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 (seeof US Patent Application Publication No. 2023/0035794).

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. 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.

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.

shows the whole of a shoe S including a sole structureand an upperfor 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.

As shown in, the sole structureincludes an outsoleand a midsole.

In the embodiment of the present disclosure, the sole structureis shown for a left foot only. Although not shown, the sole structure for a right foot is symmetrical to the sole structurefor a left foot. In the following description, only the sole structurefor a left foot will be described, and the description of the sole structure for a right foot will be omitted.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. The terms “medial side” and “lateral side” in the figures represent a positional relationship of the sole structurein the foot width direction. The terms “front” and “rear” in the figures represent a positional relationship of the sole structurein the foot length direction.

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

As shown in, the outsoleis stacked below the midsole. The outsoleis made of a hard elastic material harder than the midsole.

Specifically, examples of the material for the outsoleinclude 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 outsoleis preferably set to 50 A to 80 A (more preferably 60 A to 70 A), for example.

As shown in, the outsoleincludes a first outsole portion, a second outsole portion, and a third outsole portion.

The first outsole portionis located at part of the sole structurethat corresponds to the forefoot portion F of the foot of the wearer. The first outsole portionis attached to the lower surface of a first midsole portiondescribed later.

The second outsole portionis located at part of the sole structurethat corresponds to the forefoot portion F of the foot of the wearer. The second outsole portionis attached to an exterior portiondescribed later. Specifically, the second outsole portionis attached to the lower surface of a bottom portiondescribed later.

The third outsole portionis located at part of the sole structurethat corresponds to the rear foot portion H of the foot of the wearer. The third outsole portionis attached to the lower surface of a second midsole portiondescribed later.