US20260041196A1

US20260041196A1 - Sole

Info

Publication number: US20260041196A1
Application number: US19/292,736
Authority: US
Inventors: Kenta Hachiuma; Shin HIRAI; Kohei Mimura
Original assignee: Mizuno Corp
Current assignee: Mizuno Corp
Priority date: 2024-08-09
Filing date: 2025-08-06
Publication date: 2026-02-12
Also published as: DE102025131591A1

Abstract

A boundary portion located between an upper and a midsole in a foot width direction includes a first boundary portion. The first boundary portion is positioned at a portion of the sole corresponding to a lateral side of the wearer's forefoot. An expansion portion is positioned at a portion of the midsole corresponding to the lateral side of the wearer's forefoot. The expansion portion bulges from the first boundary portion toward the lateral side of the sole with respect to the first boundary portion in the foot width direction. An outsole has a roll-up portion protruding upward from a peripheral edge portion of an upper surface of the outsole. The roll-up portion is located at a portion corresponding to the expansion portion of the midsole and covers a peripheral edge portion of the expansion portion from the outside.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2024-133814 filed on Aug. 9, 2024, and Japanese Patent Application No. 2025-078807 filed on May 9, 2025, the entire disclosure of which is incorporated by reference herein

BACKGROUND

The present disclosure relates to a sole of a shoe.
Shoes such as those in Japanese Patent No. 7402230 (Patent Document 1), for example, have been proposed as shoes intended to improve stability at landing during running and walking.
Specifically, Patent Document 1 discloses shoes including an outsole having a ground contact surface, a midsole fixed onto the outsole, and an upper joined to the midsole along the peripheral edge of the midsole.
The midsole has the function of absorbing impact (i.e., cushioning properties). The midsole is made of a material that absorbs impact (i.e., relatively soft elastic material), such as foamed EVA, foamed urethane, GEL, and cork.

SUMMARY

Some indoor sports, such as volleyball or handball, may include intense movements in a foot width direction. Specifically, these indoor sports frequently involve turning movements such as side stepping.
The side stepping is a jumping movement in the foot width direction, performed by applying the wearer's weight to the ball of the little toe (the lateral side of the forefoot) and pushing against the floor. When the ball of the little toe of the wearer's foot (the lateral side of the forefoot) is pushed against the floor during the side stepping, the weight shift occurs from the medial side to the lateral side at a peripheral edge portion of the midsole corresponding to the lateral side portion of the forefoot of the wearer. This weight shift causes a relatively large compressive load (load acting in a compression direction) applied to the peripheral edge portion of the midsole corresponding to the lateral side of the wearer's forefoot.
If the shoes of Patent Document 1 are used in the above indoor sports, and the wearer performs side stepping, the peripheral edge portion of the midsole, made of a relatively soft elastic material, corresponding to the lateral side of the wearer's forefoot is temporarily compressed by the compressive load described above. For this reason, when the wearer performs side stepping, the foot of the wearer excessively tilts toward the lateral side. As a result, the foot of the wearer becomes unstable, making it difficult to jump in the foot width direction. This interferes with side stepping.
The present disclosure has been made in view of the above circumstances, and its object is to stabilize a foot of a wearer performing a turning movement such as side stepping during indoor sports.
In order to achieve the above object, a first aspect of the disclosure relates to a sole for a shoe including an upper. The sole includes: a midsole; and an outsole stacked on a lower side of the midsole and made of a material having a higher rigidity than that of the midsole. With the upper attached to the midsole, the midsole is provided with a boundary portion located between the upper and the midsole in a foot width direction. The boundary portion includes a first boundary portion positioned at a portion of the sole corresponding to a lateral side of a forefoot of a wearer's foot. The midsole has an expansion portion positioned at a portion of the sole corresponding to the lateral side of the forefoot of the wearer's foot. The expansion portion bulges from the first boundary portion toward the lateral side of the sole with respect to the first boundary portion in the foot width direction. The outsole has a roll-up portion protruding upward from a peripheral edge portion of an upper surface of the outsole. The roll-up portion is located at a portion corresponding to the expansion portion of the midsole and covers a peripheral edge portion of the expansion portion from the outside.
According to the first aspect of the disclosure, the sole has the expansion portion in the midsole. Thus, the edge portion on the lateral side of the ground contact surface of the sole is positioned farther laterally than the portion of the sole corresponding to the ball of the little toe (the lateral side of the forefoot) of the wearer's foot. It is thus possible to reduce excessive tilting of the wearer's foot toward the lateral side when the wearer performs side stepping.
Further, the roll-up portion of the outsole enables support of the midsole to reduce tilting effectively. Specifically, the roll-up portion of the outsole is made of the material having a higher rigidity than the midsole, and is therefore less likely to deform as compared to the midsole. The roll-up portion is located at the portion corresponding to the expansion portion of the midsole and covers the peripheral edge portion of the expansion portion from the outside, thereby making it possible to support the midsole and reduce its deformation.
As a result, it is possible to reduce excessive tilting of the wearer's foot toward the lateral side when the wearer performs side stepping. Thus, according to the first aspect of the disclosure, the wearer's foot can be stabilized when the wearer makes a turning movement such as side stepping during indoor sports.
A second aspect of the disclosure is an embodiment of the first aspect. In the second aspect, the expansion portion is positioned at least on a lateral side of a portion of the midsole corresponding to a ball of the little toe of the wearer's foot.
According to the second aspect of the disclosure, owing to the expansion portion, the edge portion on the lateral side of the ground contact surface of the sole is positioned farther laterally than the portion of the sole corresponding to the ball of the little toe of the wearer's foot. It is thus possible to reduce excessive tilting of the wearer's foot toward the lateral side when the wearer performs side stepping. Further, at least the ball of the little toe of the wearer's foot can be appropriately supported by the expansion portion when the wearer performs side stepping. Thus, according to the second aspect of the disclosure, the wearer's foot can be stabilized when the wearer makes a turning movement such as side stepping during indoor sports.
A third aspect of the disclosure is an embodiment of the first aspect. In the third aspect, a maximum dimension of the expansion portion in the foot width direction is a length equal to or greater than a dimension of the ball of the little toe of the wearer's foot in the foot width direction.
According to the third aspect of the disclosure, a maximum dimension of the expansion portion in the foot width direction is a length equal to or greater than a dimension of the ball of the little toe of the wearer in the foot width direction. Thus, owing to the expansion portion, the edge portion on the lateral side of the ground contact surface of the sole is positioned farther laterally than the portion of the sole corresponding to the ball of the little toe of the wearer's foot. It is thus possible to reduce excessive tilting of the wearer's foot toward the lateral side when the wearer performs side stepping. Further, at least the ball of the little toe of the wearer's foot can be appropriately supported by the expansion portion when the wearer performs side stepping. Thus, according to the third aspect of the disclosure, the wearer's foot can be stabilized when the wearer makes a turning movement such as side stepping during indoor sports.
A fourth aspect of the disclosure is an embodiment of the first aspect. In the fourth aspect, a dimension of the expansion portion in the foot width direction is a length of 10 mm or more.
According to the fourth aspect of the disclosure, a dimension of the expansion portion in the foot width direction is a length of 10 mm or more. Thus, owing to the expansion portion, the edge portion on the lateral side of the ground contact surface of the sole is positioned farther laterally than the portion of the sole corresponding to the ball of the little toe (the lateral side of the forefoot) of the wearer's foot. It is thus possible to reduce excessive tilting of the wearer's foot toward the lateral side when the wearer performs side stepping. Further, at least the ball of the little toe of the wearer's foot can be appropriately supported by the expansion portion when the wearer performs side stepping. Thus, according to the fourth aspect of the disclosure, the wearer's foot can be stabilized when the wearer makes a turning movement such as side stepping during indoor sports.
A fifth aspect of the disclosure is an embodiment of the first aspect. In the fifth aspect, a height of the roll-up portion in an upper-lower direction at a position corresponding to part of the midsole corresponding to a lateral side of a metatarsophalangeal joint of the wearer's foot is equal to or greater than half a distance between a lower surface of the outsole and an upper surface of the midsole.
According to the fifth aspect of the disclosure, the height of the roll-up portion in the upper-lower direction is equal to or greater than half the distance between the lower surface of the outsole and the upper surface of the midsole. Thus, the roll-up portion of the outsole can support the midsole and reduce deformation of the midsole. As a result, it is possible to reduce excessive tilting of the wearer's foot toward the lateral side when the wearer performs side stepping. Further, at least the ball of the little toe of the wearer's foot can be appropriately supported by the expansion portion when the wearer performs side stepping. Thus, according to the fifth aspect of the disclosure, the wearer's foot can be stabilized when the wearer makes a turning movement such as side stepping during indoor sports.
A sixth aspect of the disclosure is an embodiment of the first aspect. In the sixth aspect, a height of the roll-up portion in an upper-lower direction at a position corresponding to part of the midsole corresponding to a lateral side of a metatarsophalangeal joint of the wearer's foot is 12 mm or more.
According to the sixth aspect of the disclosure, the height of the roll-up portion in the upper-lower direction is 12 mm or more. Thus, the roll-up portion of the outsole can support the midsole and reduce deformation of the midsole. As a result, it is possible to reduce excessive tilting of the wearer's foot toward the lateral side when the wearer performs side stepping. Further, at least the ball of the little toe of the wearer's foot can be appropriately supported by the expansion portion when the wearer performs side stepping. Thus, according to the sixth aspect of the disclosure, the wearer's foot can be stabilized when the wearer makes a turning movement such as side stepping during indoor sports.
A seventh aspect of the disclosure is an embodiment of the first aspect. In the seventh aspect, a thickness of at least part of a region of the midsole corresponding to a wearer's toe is greater than a thickness of a region of the midsole corresponding to a wearer's metatarsophalangeal joint.
Indoor sports frequently involve not only a turning movement such as side stepping but also a jumping movement in the vertical direction (upward) with a runup. A jumping movement with a runup, in a case of a jump with both feet, is a movement of jumping upward by converting a horizontal force from the runup to an upward force by pushing against the floor by applying weight to the ball of the big toe (inner side of the forefoot) of one foot and to the forefoot F of the other foot, from the ball of the big toe to the ball of the little toe B (outer side of the forefoot) and the toe.
When the ball of the little toe and the toe of the wearer's foot are pushed against the floor during a jump with a runup, the weight shift from the medial side toward the lateral side and the toe occurs at a peripheral edge portion of the midsole corresponding to the lateral side portion of the forefoot of the wearer. This weight shift causes a relatively large compressive load (load acting in the compression direction) applied to the peripheral edge portion of the midsole corresponding to the lateral side of the wearer's forefoot.
According to the seventh aspect of the disclosure, the thickness of at least part of a region of the midsole corresponding to the wearer's toe is greater than the thickness of a region of the midsole corresponding to the wearer's metatarsophalangeal joint. Thus, excessive sinking of the midsole can be reduced even when a relatively large compressive load is applied to the peripheral edge portion of the midsole corresponding to the lateral side of the wearer's forefoot due to the weight shift during a jump with a runup. Thus, according to the seventh aspect of the disclosure, the wearer's foot can be further stabilized during indoor sports.
As can be seen from the foregoing description, it is possible to stabilize the foot of the wearer performing a turning movement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall perspective view of a sole according to a first embodiment of the present disclosure, as viewed from a lateral side.

FIG. 2 is an exploded perspective view of the sole illustrated in FIG. 1 .

FIG. 3 is a plan view of the sole illustrated in FIG. 1 .

FIG. 4 is a side view of the sole illustrated in FIG. 1 , as viewed from the lateral side.

FIG. 5 is a sectional view taken along line V-V of FIG. 3 .

FIG. 6 is an enlarged view of a portion VI in FIG. 5 .

FIG. 7 is a view corresponding to FIG. 4 , illustrating a sole according to a variation of the first embodiment of the present disclosure.

FIG. 8 is a plan view of a sole according to a second embodiment of the present disclosure.

FIG. 9 is a schematic sectional view taken along line IX-IX of FIG. 8 .

FIG. 10 is a schematic sectional view taken along line X-X of FIGS. 8 and 9 .

FIG. 11 is a schematic sectional view taken along line XI-XI of FIGS. 8 and 9 .

FIG. 12 is a schematic sectional view taken along line XII-XII of FIGS. 8 and 9 .

DETAILED DESCRIPTION

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

First Embodiment

In a first embodiment of the present disclosure, only a sole 1 for a left foot will be described as an example. A sole for a right foot is symmetrical to the sole 1 for the left foot. In the following description, only the sole 1 for the left foot will be described, and the description of the sole for the right foot will be omitted.
In the following description, the expressions “above (upper side, upward, top)” and “below (lower side, downward, bottom) represent a positional relationship between components of the sole 1 in the upper-lower direction. The expressions “front (forward)” and “rear (rearward)” represent a positional relationship between the components of the sole 1 in the front-rear direction. The expressions “medial side” and “lateral side” represent a positional relationship between the components of the sole 1 in the foot width direction.
Further, in the sole 1 illustrated in FIG. 3 , an area corresponding to the forefoot of the wearer's foot is indicated by a reference character F; an area corresponding to the midfoot of the wearer's foot is indicated by a reference character M; and an area corresponding to the rearfoot of the wearer's foot is indicated by a reference character R. The wearer's foot is indicated by a reference character ft (dash-dot-dot line) in FIGS. 3 and 4 .

(Sole)

FIG. 1 illustrates the entirety of the sole 1 according to the first embodiment of the present disclosure. The sole 1 is applicable to a sole of a shoe for use in sports of an indoor category, such as volleyball or handball, involving a turning movement such as side stepping.

(Midsole)

As illustrated in FIGS. 1 to 7 , the sole 1 includes a midsole 10. The midsole 10 is configured to support a plantar surface of the wearer. The midsole 10 is stacked on the upper side of an outsole 20 (described later) in a thickness direction. The shoe including the sole 1 has an upper 2 attached, for example, to the midsole 10 for covering the wearer's foot ft.
Specifically, non-limiting examples of a material suitable for the midsole 10 include thermoplastic synthetic resins such as an ethylene-vinyl acetate copolymer (EVA) and foams thereof, thermosetting resins such as polyurethane (PU) and foams thereof, and rubbers such as butadiene rubber and chloroprene rubber and foams thereof. The midsole 10 preferably has a hardness of, for example, 15 C to 65 C on the Asker C scale.

(Boundary Portion)

As illustrated in FIG. 5 , the midsole 10 has a boundary portion 11. With the upper 2 attached to the midsole 10, the boundary portion 11 is located between the upper 2 and the midsole 10 in the foot width direction.
The boundary portion 11 includes a first boundary portion 12. The first boundary portion 12 is positioned at a portion of the sole 1 corresponding to the lateral side of the forefoot F of the wearer's foot ft.
As illustrated in FIGS. 1 to 7 , the boundary portion 11 is provided on the upper surface of the midsole 10. The boundary portion 11 is provided along a peripheral edge portion of the midsole 10.
As illustrated in FIG. 3 , the first boundary portion 12 is disposed at a peripheral edge portion of the midsole 10 near the lateral side. The first boundary portion 12 extends across a portion of the midsole 10 corresponding to the lateral side of the metatarsophalangeal joint MP of the wearer's foot ft. The first boundary portion 12 is disposed in an area from a front end portion of the midsole 10 to a portion of the midsole 10 corresponding to a rear portion of the forefoot F of the wearer's foot ft. Specifically, assuming the length of the midsole 10 in a foot length direction from the heel to the toe is 100%, the first boundary portion 12 is disposed in a region at least from a position 60% from the heel to a position 85% from the heel.

(Expansion Portion)

As illustrated in FIGS. 1 to 6 , the midsole 10 includes an expansion portion 13. The expansion portion 13 is positioned at a portion of the sole 1 corresponding to the lateral side of the forefoot F of the wearer's foot ft.
As illustrated in FIGS. 3, 5, and 6 , the expansion portion 13 bulges from the first boundary portion 12 toward the lateral side of the sole 1 with respect to the first boundary portion 12 in the foot width direction.
As illustrated in FIG. 3 , the expansion portion 13 is positioned at least on the lateral side of a portion of the midsole 10 corresponding to the ball of the little toe B of the wearer's foot ft. The expansion portion 13 bulges toward the lateral side in the foot width direction relative to the first boundary portion 12.
As illustrated in FIGS. 5 and 6 , the maximum dimension of the expansion portion 13 in the foot width direction is defined as a dimension A. As illustrated in FIG. 3 , the dimension of the ball of the little toe B of the wearer's foot ft in the foot width direction is defined as a dimension E. The dimension A is greater than or equal to the dimension E. Specifically, the dimension A is 10 mm or more.
As illustrated in FIG. 3 , the expansion portion 13 is positioned at a portion of the midsole 10 corresponding to the lateral side of the metatarsophalangeal joint MP of the wearer's foot ft. The expansion portion 13 is disposed over an area from the front end portion of the midsole 10 to a portion of the midsole 10 corresponding to a boundary portion between the forefoot F and the midfoot M of the wearer's foot ft. Assuming the length of the sole 1 in the foot length direction from the heel to the toe is 100%, the expansion portion 13 is disposed on the lateral side of a region at least from a position 60% from the heel to a position 85% of the heel.
As illustrated in FIG. 3 , the expansion portion 13 bulges the most to the lateral side at the portion of the midsole 10 corresponding to the lateral side of the metatarsophalangeal joint MP of the wearer's foot ft. The expansion portion 13 bulges less as it approaches the front end portion of the midsole 10. The expansion portion 13 bulges less as it approaches the portion of the midsole 10 corresponding to the rear portion of the forefoot F of the wearer's foot ft.
As illustrated in FIGS. 5 and 6 , the size of the expansion portion 13 in the foot width direction is substantially constant in an upper-lower direction in a portion from the lower surface to the upper surface of the midsole 10. That is, a portion of the expansion portion 13 corresponding to the dimension D has a substantially constant size in the foot width direction along the upper-lower direction. On the other hand, in a portion of the expansion portion 13 from the upper surface of the midsole 10 to a top portion 15, the size of the expansion portion 13 in the foot width direction gradually decreases from the upper surface of the midsole 10 (i.e., from a portion corresponding to the upper end of the dimension D) toward the top portion 15.

(Protrusion)

As illustrated in FIGS. 1 to 7 , the expansion portion 13 has a protrusion 14. The protrusion 14 protrudes upward from the upper surface of the midsole 10. The protrusion 14 is formed over the entire circumference of a peripheral edge portion of the upper surface of the midsole 10.
As illustrated in FIGS. 4 and 7 , the cross-sectional shape of the protrusion 14 is substantially a triangular shape. The protrusion 14 includes the top portion 15 at the upper portion. The upper 2 is attached to the vicinity of the top portion 15. The protrusion 14 includes a side portion 16 facing the wearer's foot ft. The protrusion 14 includes a first protrusion 17 positioned at a portion of the sole 1 corresponding to the lateral side of the forefoot F of the wearer's foot ft.
As illustrated in FIG. 5 , with the upper 2 attached to the protrusion 14, the protrusion 14 has the boundary portion 11 between the upper 2 and the protrusion 14. As illustrated in FIGS. 5 and 6 , the boundary portion 11 corresponds to a line drawn vertically from the top portion 15. The boundary portion 11 is positioned between the upper 2 and the midsole 10 in the foot width direction. The boundary portion 11 includes the first boundary portion 12 positioned at a portion of the sole 1 corresponding to the lateral side of the forefoot F of the wearer's foot ft.

(Outsole)

As illustrated in FIGS. 1 to 6 , the sole 1 includes the outsole 20. The outsole 20 is stacked on the lower side of the midsole 10. The outsole 20 is made of a material having a higher rigidity than the midsole 10.
The outsole 20 is disposed in a region of the sole 1 corresponding to an area of the wearer's foot ft extending from the forefoot F to the rearfoot R. The upper surface of the outsole 20 is fixed to the lower surface of the midsole 10 with an adhesive or the like, for example.
Examples of the material suitable for the outsole 20 include thermoplastic synthetic resins such as an 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 these materials. The hardness of the outsole 20 is preferably set to, e.g., 50 A to 80 A (more preferably 60 A to 70 A) by a durometer C or A.

(Roll-Up Portion)

As illustrated in FIGS. 2 and 4 to 6 , the outsole 20 includes a roll-up portion 21. The roll-up portion 21 protrudes upward from a peripheral edge portion of the upper surface of the outsole 20. The roll-up portion 21 is positioned at a portion corresponding to the expansion portion 13 of the midsole 10. The roll-up portion 21 covers a peripheral edge portion of the expansion portion 13 from the outside.
Here, as illustrated in FIG. 5 , the height of the roll-up portion 21 in the upper-lower direction is defined as a dimension h. A distance between the lower surface of the outsole 20 and the upper surface of the midsole 10 is defined as a dimension D. Specifically, the dimension h is a dimension corresponding to the portion of the midsole 10 corresponding to the lateral side of the metatarsophalangeal joint MP of the wearer's foot ft. The dimension D is a dimension of a portion of the midsole 10 corresponding to a central portion of the metatarsophalangeal joint MP of the wearer's foot ft in the foot width direction. The dimension h is a height that is at least half of the dimension D. Specifically, the dimension h is a height of 12 mm or more.
As illustrated in FIG. 4 , the dimension h decreases toward the rear side from the portion of the midsole 10 corresponding to the lateral side of the metatarsophalangeal joint MP of the wearer's foot ft. Assuming the length of the sole 1 in the foot length direction from the feel to the toe is 100%, the dimension h is of the lateral side of the outsole 20 in a region at least from a position 60% from the heel to a position 85% from the heel.
As illustrated in FIGS. 5 and 6 , the dimension of the roll-up portion 21 in the foot width direction decreases as the roll-up portion 21 extends upward. The length of a lower portion of the roll-up portion 21 in the foot width direction is defined as a dimension w. Specifically, the dimension w is a dimension of a portion of the outsole 20 corresponding to the lateral side of the metatarsophalangeal joint MP of the wearer's foot ft. A length between the upper surface and the lower surface of the outsole 20 is defined as a dimension t. Specifically, the dimension t is a dimension of a portion of the outsole 20 corresponding to the lateral side of the metatarsophalangeal joint MP of the wearer's foot ft. The dimension w is a length approximately equal to the dimension t.
As illustrated in FIGS. 5 and 6 , the lower portion of the roll-up portion 21 projects to the lateral side.

(Movement of Expansion Portion)

Next, with reference to FIGS. 3 and 6 , a description will be given of how the expansion portion 13 and the roll-up portion 21 support the peripheral edge portion of the midsole 10 corresponding to the lateral side of the forefoot F when the peripheral edge portion tilts in pushing against the floor during side stepping.
For example, some indoor sports, such as volleyball or handball, may include intense movements in a foot width direction. Specifically, these indoor sports frequently involve turning movements such as side stepping.
The side stepping is a jumping movement in the foot width direction, performed by applying the wearer's weight to the ball of the little toe B (the lateral side of the forefoot F) and pushing against the floor. When the ball of the little toe B of the wearer's foot ft (the lateral side of the forefoot F) is pushed against the floor during the side stepping, the weight shift from the medial side to the lateral side occurs at a peripheral edge portion of the midsole 10 corresponding to the lateral side position of the forefoot F of the wearer. This weight shift causes a relatively large compressive load C (load acting in a compression direction) applied to the peripheral edge portion of the midsole 10 corresponding to the lateral side of the wearer's forefoot F.
The compressive load C (load acting in the compression direction) generated by the weight shift of the wearer is input to the midsole 10 from a portion of the sole 1 corresponding to the ball of the little toe B (the lateral side of the forefoot F) of the wearer's foot ft. Here, the load input to the midsole 10 will be described by decomposing the load into a component force Cz in the upper-lower direction and a component force Cy in the foot width direction. The component force Cz in the upper-lower direction, together with a reaction force Rz pushed back from the upper surface of the outsole 20, acts to compress the peripheral edge portion of the midsole 10 on the lateral side in the upper-lower direction.
The component force Cy in the foot width direction acts to cause the side portion 16 of the first protrusion 17 on the lateral side of the midsole 10 to tilt toward the lateral side, using an edge portion on the lateral side of the ground contact surface of the sole 1 as a center of rotation. At this time, since the midsole 10 has the expansion portion 13, the edge portion on the lateral side of the ground contact surface of the sole 1 is positioned farther laterally than the portion of the sole 1 corresponding to the ball of the little toe B (the lateral side of the forefoot F) of the wearer's foot ft. It is thus possible to resist the tilting of the sole 1.
Further, the roll-up portion 21 of the outsole 20 receives the component force Cy in the foot width direction and pushes it back as a reaction force Ry. The roll-up portion 21 is made of the material having a higher rigidity than the midsole 10, and is therefore less likely to deform as compared to the midsole 10. The roll-up portion 21 is located at the portion corresponding to the expansion portion 13 of the midsole 10 and covers the peripheral edge portion of the expansion portion 13 from the outside. It is thus possible to support the midsole 10 and reduce its deformation.
If the expansion portion 13 is formed only of the outsole 20, the rigidity of the sole 1 will be greater than required. This may lead to insufficient cushioning properties of the sole 1.

[Problems of Prior Art]

Shoes such as those in Patent Document 1 have been proposed as shoes intended to improve stability at landing during running and walking.
The shoes of Patent Document 1 include the outsole having the ground contact surface, the midsole fixed onto the outsole, and the upper joined to the midsole along the peripheral edge of the midsole.
The midsole has the function of absorbing impact (i.e., cushioning properties). The midsole is made of a material that absorbs impact (i.e., relatively soft elastic material), such as foamed EVA, foamed urethane, GEL, and cork. The midsole has a bulge. The bulge is shaped such that the outer edge of the bottom surface of the midsole is located on the lateral side relative to the joint portion between the upper and the midsole in plan view.
In the shoes of Patent Document 1, the stability at landing is enhanced by the bulge of the midsole. Particularly, if the bulge is made of the same material as the other portion of the midsole except the bulge (i.e., the “other portion”) and has the same hardness as the other portion, the bulge exhibits cushioning properties equivalent to those of the midsole. As a result, the impact at landing during running and walking is easily absorbed.
Some indoor sports, such as volleyball or handball, may include intense movements in a foot width direction. Specifically, these indoor sports frequently involve turning movements such as side stepping.
The side stepping is a jumping movement in the foot width direction, performed by applying the wearer's weight to the ball of the little toe (the lateral side of the forefoot) and pushing against the floor. When the ball of the little toe of the wearer's foot (the lateral side of the forefoot) is pushed against the floor during the side stepping, the weight shift occurs from the medial side to the lateral side at a peripheral edge portion of the midsole corresponding to the lateral side portion of the forefoot of the wearer. This weight shift causes a relatively large compressive load (load acting in a compression direction) applied to the peripheral edge portion of the midsole corresponding to the lateral side of the wearer's forefoot.
Here, if the shoes of Patent Document 1 are used in the above indoor sports, and the wearer performs side stepping, the peripheral edge portions of the midsole and the bulge, made of a relatively soft elastic material, corresponding to the lateral side of the wearer's forefoot are temporarily compressed by the compressive load described above. For this reason, when the wearer performs side stepping, the foot of the wearer excessively tilts toward the lateral side. As a result, the foot of the wearer becomes unstable, making it difficult to jump in the foot width direction. This interferes with side stepping.
In order to solve the above-described problem of the prior art (Patent Document 1), the sole 1 according to the embodiment of the present disclosure is configured to stabilize the wearer's foot ft when the wearer makes a turning movement such as side stepping during indoor sports.

[Features and Effects of First Embodiment]

As described above, the sole 1 according to the first embodiment of the present disclosure includes the midsole 10 and the outsole 20. The midsole 10 has the expansion portion 13. The outsole 20 has the roll-up portion 21. The roll-up portion 21 is located at the portion corresponding to the expansion portion 13 of the midsole 10 and covers the peripheral edge portion of the expansion portion 13 from the outside.
According to this configuration, the sole 1 has the expansion portion 13 in the midsole 10. Thus, the edge portion on the lateral side of the ground contact surface of the sole 1 is positioned farther laterally than the portion of the sole 1 corresponding to the ball of the little toe B (the lateral side of the forefoot F) of the wearer's foot ft. It is thus possible to reduce excessive tilting of the wearer's foot ft toward the lateral side when the wearer performs side stepping.
Further, the roll-up portion 21 of the outsole 20 enables support of the midsole 10 to reduce tilting effectively. That is, the roll-up portion 21 of the outsole 20 receives the component force Cy in the foot width direction. The roll-up portion 21 is made of the material having a higher rigidity than the midsole 10, and is therefore less likely to deform as compared to the midsole 10. The roll-up portion 21 is located at the portion corresponding to the expansion portion 13 of the midsole 10 and covers the peripheral edge portion of the expansion portion 13 from the outside, thereby making it possible to support the midsole 10 and reduce its deformation.
As a result, it is possible to reduce excessive tilting of the wearer's foot ft toward the lateral side when the wearer performs side stepping. Thus, the wearer's foot ft can be stabilized when the wearer makes a turning movement such as side stepping during indoor sports.
The expansion portion 13 is positioned at least on the lateral side of a portion of the midsole 10 corresponding to the ball of the little toe B of the wearer's foot ft. According to this configuration, owing to the expansion portion 13, the edge portion on the lateral side of the ground contact surface of the sole 1 is positioned farther laterally than the portion of the sole 1 corresponding to the ball of the little toe B (the lateral side of the forefoot F) of the wearer's foot ft. It is thus possible to reduce excessive tilting of the wearer's foot ft toward the lateral side when the wearer performs side stepping. Further, at least the ball of the little toe B of the wearer's foot ft can be appropriately supported by the expansion portion 13 when the wearer performs side stepping. Thus, the wearer's foot ft can be stabilized when the wearer makes a turning movement such as side stepping during indoor sports.
The maximum dimension A of the expansion portion 13 in the foot width direction is a length equal to or greater than the dimension E of the ball of the little toe B of the wearer's foot ft in the foot width direction. According to this configuration, owing to the expansion portion 13, the edge portion on the lateral side of the ground contact surface of the sole 1 is positioned farther laterally than the portion of the sole 1 corresponding to the ball of the little toe B (the lateral side of the forefoot F) of the wearer's foot ft. It is thus possible to reduce excessive tilting of the wearer's foot ft toward the lateral side when the wearer performs side stepping. Further, at least the ball of the little toe B of the wearer's foot ft can be appropriately supported by the expansion portion 13 when the wearer performs side stepping. Thus, the wearer's foot ft can be stabilized when the wearer makes a turning movement such as side stepping during indoor sports.
The maximum dimension A of the expansion portion 13 in the foot width direction is a length of 10 mm or more. According to this configuration, owing to the expansion portion 13, the edge portion on the lateral side of the ground contact surface of the sole 1 is positioned farther laterally than the portion of the sole 1 corresponding to the ball of the little toe B (the lateral side of the forefoot F) of the wearer's foot ft. It is thus possible to reduce excessive tilting of the wearer's foot ft toward the lateral side when the wearer performs side stepping. Further, at least the ball of the little toe B of the wearer's foot ft can be appropriately supported by the expansion portion 13 when the wearer performs side stepping. Thus, the wearer's foot ft can be stabilized when the wearer makes a turning movement such as side stepping during indoor sports.
The dimension h of the roll-up portion 21 in the upper-lower direction is a height equal to or greater than half the distance dimension D between the lower surface of the outsole 20 and the upper surface of the midsole 10. According to this configuration, the roll-up portion 21 of the outsole 20 receives the component force Cy in the foot width direction, thereby supporting the midsole 10 and reducing its deformation. It is thus possible to reduce excessive tilting of the wearer's foot ft toward the lateral side when the wearer performs side stepping. Further, at least the ball of the little toe B of the wearer's foot ft can be appropriately supported by the expansion portion 13 when the wearer performs side stepping. Thus, the wearer's foot ft can be stabilized when the wearer makes a turning movement such as side stepping during indoor sports.
The dimension h is a height of 12 mm or more. According to this configuration, the height h of the roll-up portion 21 in the upper-lower direction is 12 mm or more. Thus, the roll-up portion 21 of the outsole 20 receives the component force Cy in the foot width direction, thereby supporting the midsole 10 and reducing its deformation. It is thus possible to reduce excessive tilting of the wearer's foot ft toward the lateral side when the wearer performs side stepping. Further, at least the ball of the little toe B of the wearer's foot ft can be appropriately supported by the expansion portion 13 when the wearer performs side stepping. Thus, the wearer's foot ft can be stabilized when the wearer makes a turning movement such as side stepping during indoor sports.

[Variation of First Embodiment]

In the first embodiment above, the height (dimension h) of the roll-up portion 21 in the upper-lower direction is less than the distance (dimension D) between the lower surface of the outsole 20 and the upper surface of the midsole 10, but is not limited thereto.
For example, as illustrated in FIG. 7 , the roll-up portion 21 of the variation may be configured such that at least part of the roll-up portion 21 (a roll-up extension portion 22 illustrated in FIG. 7 ) covers the peripheral edge portion of the expansion portion 13 entirely from the outside. Specifically, part of the roll-up portion 21 where the roll-up extension portion 22 is located may be configured to have the height dimension h greater than the dimension D in the upper-lower direction. Further, the part of the roll-up portion 21 where the roll-up extension portion 22 is located may extend to the position of the upper 2 in the upper-lower direction (to the position above the top portion 15 illustrated in FIGS. 5 and 6 ).
The roll-up portion 21 of this variation can further enhance the durability of the expansion portion 13 of the midsole 10. That is, the deformation of the midsole 10 (particularly, expansion portion 13) can be further reduced by the roll-up portion 21 having the roll-up extension portion 22. As a result, it is possible to reduce excessive tilting of the wearer's foot ft toward the lateral side when the wearer performs side stepping.

Second Embodiment

FIGS. 8 to 12 illustrate a sole 1 of a second embodiment of the present disclosure. The second embodiment differs from the midsole 10 of the sole 1 according to the first embodiment mainly in the structure of the midsole 10. The other configurations of the sole 1 of the second embodiment are similar to the configurations of the sole 1 of the first embodiment. Therefore, the same reference characters are used to designate the same elements as those illustrated in FIGS. 1 to 7 , and detailed description thereof is omitted herein.

(Midsole)

Reference character MA illustrated in FIGS. 8 and 9 denotes a region of the midsole 10 of the sole 1 which corresponds to the metatarsophalangeal joint MP of the wearer. Assuming the length of the midsole 10 in the foot length direction from the heel to the toe is 100%, the length of the region MA in the foot length direction corresponds to the length from a position 60% from the heel to a position 75% from the heel. Reference character TA illustrated in FIGS. 8 and 9 denotes a region of the midsole 10 corresponding to the wearer's toe T. Assuming the length of the midsole 10 in the foot length direction from the heel to the toe is 100%, the length of the region TA in the foot length direction corresponds to the length from a position 75% from the heel to 100% from the heel.
As illustrated in FIG. 9 , the thickness of part of the region TA is greater than the thickness of the region MA. Preferably, assuming the length of the midsole 10 in the foot length direction from the heel to the toe is 100%, part of the region TA that is from a position 75% from the heel to a position 98% from the heel has a thickness greater than the thickness of the region MA. Specifically, a difference between the thickness dimension of the region TA and the thickness dimension of the region MA is greater than the 0 mm and 5 mm or less.
If the difference between the thickness dimension of part of the region TA and the thickness dimension of the region MA is greater than 5 mm, the wearer's foot ft is easily dorsiflexed. The dorsiflexion is a movement in which an ankle joint is bent toward the instep of the foot. When the wearer's foot ft is dorsiflexed, movements of the ankle joint are restricted, causing difficulties in walking, for example.
The thickness dimension of the region MA is 15 mm or more and 30 mm or less. Preferably, the thickness dimension of the region MA is 20 mm or more and 25 mm or less.
Indoor sports frequently involve not only the turning movement such as side stepping described in the first embodiment but also a jumping movement in the vertical direction (upward) with a runup. The jumping movement with a runup is a movement of jumping upward. In order to exhibit higher performance in the jumping movement with a runup, the thickness dimension of the region MA is preferably 15 mm or more. On the other hand, for stable performance in, for example, side stepping during the indoor sports, the thickness dimension of the region MA is preferably 30 mm or less.
The thicknesses of the midsole 10 at the positions of an X-X cross-sectional line, an XI-XI cross-sectional line, and an XII-XII cross-sectional line are described as an example. The X-X cross-sectional line is a cross-sectional line including the ball of the little toe B and extending along the foot width direction. The XI-XI cross-sectional line is a cross-sectional line including the distal phalanx of the little toe and extending along the foot width direction. The XII-XII cross-sectional line is a cross-sectional line including the distal phalanx of the second toe and extending along the foot width direction.
As illustrated in FIG. 10 , at the position of the X-X cross-sectional line of the region MA, the thickness dimension t10 a of the midsole 10 on the lateral side is set to, for example, 27 mm. The thickness dimension t10 b of the midsole 10 on the medial side is set to, for example, 26 mm. The thickness dimension t10 c of a middle portion of the midsole 10 between the lateral side and the medial side is set to, for example, 23 mm.
As illustrated in FIG. 11 , at the position of the XI-XI cross-sectional line of the region TA, the thickness dimension t10 a of the midsole 10 on the lateral side is set to, for example, 28 mm. The thickness dimension t10 b of the midsole 10 on the medial side is set to, for example, 28 mm. The thickness dimension t10 c of a middle portion of the midsole 10 between the lateral side and the medial side is set to, for example, 25 mm.
As illustrated in FIG. 12 , at the position of the XII-XII cross-sectional line of the region TA, the thickness dimension t10 a of the midsole 10 on the lateral side is set to, for example, 27 mm. The thickness dimension t10 b of the midsole 10 on the medial side is set to, for example, 26 mm. The thickness dimension t10 c of a middle portion of the midsole 10 between the lateral side and the medial side is set to, for example, 26 mm.
As illustrated in FIG. 9 , the lower surface (lower surface of the outsole 20) of the region of the sole 1 corresponding to the wearer's midfoot M is formed flat. That is, the lower surface of the region of the sole 1 corresponding to the wearer's midfoot M is not arch-shaped. Thus, the material forming the midsole 10 can be arranged at a portion of the sole 1 corresponding to the wearer's midfoot M in the upper-lower direction of the sole 1. This configuration improves the cushioning properties of the sole 1 in the region of the sole 1 corresponding to the wearer's midfoot M. This can increase an upward jumping force in a jumping movement.

[Specific Problem to be Solved by Second Embodiment]

As mentioned above, indoor sports frequently involve not only a turning movement such as side stepping but also a jumping movement in the vertical direction (upward) with a runup. In a jump with both feet, the wearer's weight is applied to the ball of the big toe of one foot and to the other foot from the ball of the big toe to the ball of the little toe B and the toe T to push against the floor. By pushing against the floor, a horizontal force from the runup is converted into an upward force.
When the wearer performs a jump with a runup, the ball of the little toe B and the toe T of the wearer are pushed against the floor. In the pushing against the floor, the weight shift from the ball of the big toe to the ball of the little toe B and the toe T occurs at the peripheral edge portion of a part of the midsole 10 corresponding to the lateral side of the wearer's forefoot F. This weight shift causes a relatively large compressive load (load acting in the compression direction) CT (see FIG. 9 ) applied to the peripheral edge portion of the part of the midsole 10 corresponding to the lateral side of the wearer's forefoot F.
Here, a configuration assuming that the above-described shoes of Patent Document 1 are used for the indoor sports will be studied (hereinafter simply referred to as a “hypothetical configuration”). In the hypothetical configuration, the thickness of a portion of the midsole corresponding to the forefoot of the wearer is not disclosed. If the thickness of the midsole is constant over the entire midsole in the foot length direction from the heel to the toe, it may interfere with a jump with a runup. This is because when the wearer performs a jump with a runup, the peripheral edge portion of a part of the midsole corresponding to the lateral side of the forefoot of the wearer and a region of the midsole 10 corresponding to the toe are temporarily compressed by the compressive load described above. Thus, when the wearer performs a jump with a runup, the wearer's foot excessively tilts from the ball of the big toe toward the ball of the little toe B and the toe T. As a result, the foot of the wearer becomes unstable, making it difficult to jump upward.
In order to solve the above-described problem of the prior art (the hypothetical configuration), the sole 1 according to the second embodiment of the present disclosure is configured to stabilize the wearer's foot ft when the wearer makes a jumping movement with a runup during indoor sports.

[Features and Effects of Second Embodiment]

The compressive load CT generated by the weight shift of the wearer is input to the midsole 10 from a portion of the sole 1 corresponding to the toe T of the wearer's foot ft, as illustrated in FIG. 9 . The compressive load CT is a downward load. The compressive load CT, together with a reaction force RT pushed back from the upper surface of the outsole 20, acts to compress the region TA of the midsole 10 in the upper-lower direction.
As a characteristic configuration according to the second embodiment of the present disclosure, the thickness of at least part of the region TA of the midsole 10 corresponding to the toe T of the wearer is greater than the thickness of the region MA corresponding to the metatarsophalangeal joint MP of the wearer. This configuration does not interfere with a jump with a runup. This is because when the wearer performs a jump with a runup, the peripheral edge portion of a part of the midsole 10 corresponding to the lateral side of the forefoot F of the wearer and the region TA of the midsole 10 corresponding to the toe T are temporarily compressed by the compressive load CT. The thickness of at least part of the region TA of the midsole 10 is greater than the thickness of the region MA. Thus, even when compressed by the compressive load CT, the region TA of the midsole 10 can maintain a sufficient thickness. It is thus possible to reduce the excessive tilting of the wearer's foot ft from the ball of the big toe toward the ball of the little toe B and the toe T. As a result, the wearer's foot ft is stabilized when the wearer performs a jump with a runup.

[Variation of Second Embodiment]

Although not illustrated, the entire thickness of the region TA of the midsole 10 corresponding to the toe T of the wearer may be greater than the thickness of the region MA corresponding to the metatarsophalangeal joint MP of the wearer. This configuration makes it possible to stabilize the wearer's foot ft when the wearer performs a jump with a runup, as in the second embodiment.

Other Embodiments

In the above embodiments, the dimension h decreases toward the rear side from the portion of the midsole 10 corresponding to the lateral side of the metatarsophalangeal joint MP of the wearer's foot ft, but is not limited thereto. For example, the dimension h may be a constant height from the portion of the midsole 10 corresponding to the lateral side of the metatarsophalangeal joint MP of the wearer's foot ft to the rear.
In the embodiments above, the cross-sectional shape of the protrusion 14 is substantially a triangular shape, but is not limited thereto. For example, the cross-sectional shape of the protrusion 14 may be another shape such as a rectangle and a fan-like shape.
The present disclosure can be industrially applicable to a sole of a shoe for use in indoor sports such as volleyball and handball.

DESCRIPTION OF REFERENCE CHARACTERS

- 1 Sole
- 2 Upper
- 10 Midsole
- 11 Boundary Portion
- 12 First Boundary Portion
- 13 Expansion Portion
- 20 Outsole
- 21 Roll-Up Portion
- A Dimension of Expansion Portion in Foot Width Direction
- B Ball of Little Toe
- D Distance between Lower Surface of Outsole and Upper Surface of Midsole
- E Dimension of Ball of Little Toe in Foot Width Direction
- ft Foot of Wearer
- h Height of Roll-Up Portion in Upper-Lower Direction
- MP Metatarsophalangeal Joint of Wearer
- MA Region of Midsole Corresponding to Metatarsophalangeal Joint of Wearer
- T Toe of Wearer
- TA Region of Midsole Corresponding to Toe of Wearer

Claims

What is claimed is:

1. A sole for a shoe including an upper, the sole comprising:

a midsole; and an outsole stacked on a lower side of the midsole and made of a material having a higher rigidity than that of the midsole,

with the upper attached to the midsole, the midsole being provided with a boundary portion located between the upper and the midsole in a foot width direction,

the boundary portion including a first boundary portion positioned at a portion of the sole corresponding to a lateral side of a forefoot of a wearer's foot,

the midsole having an expansion portion positioned at a portion of the sole corresponding to the lateral side of the forefoot of the wearer's foot,

the expansion portion bulging from the first boundary portion toward the lateral side of the sole with respect to the first boundary portion in the foot width direction,

the outsole having a roll-up portion protruding upward from a peripheral edge portion of an upper surface of the outsole,

the roll-up portion being located at a portion corresponding to the expansion portion of the midsole, the roll-up portion covering a peripheral edge portion of the expansion portion from an outside.

2. The sole of claim 1, wherein

the expansion portion is positioned at least on a lateral side of a portion of the midsole corresponding to a ball of the little toe of the wearer's foot.

3. The sole of claim 1, wherein

a maximum dimension of the expansion portion in the foot width direction is a length equal to or greater than a dimension of the ball of the little toe of the wearer's foot in the foot width direction.

4. The sole of claim 1, wherein

a dimension of the expansion portion in the foot width direction is a length of 10 mm or more.

5. The sole of claim 1, wherein

a height of the roll-up portion in an upper-lower direction at a position corresponding to part of the midsole corresponding to a lateral side of a metatarsophalangeal joint of the wearer's foot is equal to or greater than half a distance between a lower surface of the outsole and an upper surface of the midsole.

6. The sole of claim 1, wherein

a height of the roll-up portion in an upper-lower direction at a position corresponding to part of the midsole corresponding to a lateral side of a metatarsophalangeal joint of the wearer's foot is 12 mm or more.

7. The sole of claim 1, wherein

a thickness of at least part of a region of the midsole corresponding to a wearer's toe is greater than a thickness of a region of the midsole corresponding to a wearer's metatarsophalangeal joint.