US20210298416A1

US20210298416A1 - Shoes

Info

Publication number: US20210298416A1
Application number: US17/208,308
Authority: US
Inventors: Shin HIRAI; Kentaro Yahata; Yu TAKEMURA
Original assignee: Mizuno Corp
Current assignee: Mizuno Corp
Priority date: 2020-03-27
Filing date: 2021-03-22
Publication date: 2021-09-30
Also published as: JP2022103359A; DE102021107373A1; JP2021153891A; JP7454602B2; JP7077354B2

Abstract

A sole of a shoe includes a sole body and a plurality of lower protrusions and a plurality of upper protrusions arranged at least in positions each corresponding to a forefoot in the sole body. The sole body is configured such that hardness of a portion corresponding to a midfoot is higher than hardness of a portion corresponding to the forefoot.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2020-057769 filed on Mar. 27, 2020, the entire disclosure of which is incorporated by reference herein.

BACKGROUND

The present disclosure relates to a shoe.
Conventionally, for example, a shoe descried in Japanese Patent Application No. 2019-63491 has been proposed as a shoe that a wearer wears to recognize differences of pressures transmitted to various parts of a sole.
Japanese Patent Application No. 2019-63491 discloses a shoe including a sole supporting an entire planta of a wearer, a plurality of lower protrusions protruding downward from a lower portion of the sole toward the ground and spaced from one another, and a plurality of upper protrusions protruding upward from an upper portion of the sole toward the planta of the wearer, each of the upper protrusions being on an upper side of the sole and overlapping with an associated one of the lower protrusions. The plurality of lower protrusions and the plurality of upper protrusions are arranged in an entire region of the sole both when viewed from the bottom and when viewed from the top.

SUMMARY

In the shoe of Japanese Patent Application No. 2019-63491, a reaction force from the ground acts on the plurality of lower protrusions and is transferred from the lower protrusions to the wearer's planta via the upper protrusions. Thus, the wearer can recognize differences of pressures transferred to various portions of his or her planta in the respective portions throughout the sole.
Incidentally, when the wearer exercises, a load tends to be applied to a position corresponding to a forefoot of a foot of the wearer in a sole of the shoe. Therefore, it is important to cause the pressures transferred from the lower protrusions and the upper protrusions to concentrate in the forefoot of the foot of the wearer.
However, in the shoe of Japanese Patent Application No. 2019-63491, the plurality of lower protrusions and the plurality of upper protrusions are arranged in the entire region of the sole, and therefore, the pressures transferred from the lower protrusions and the upper protrusions are dispersed throughout the planta of the wearer. That is, it is difficult to cause the pressures to concentrate in the forefoot of the foot of the wearer in the shoe.
In view of the foregoing, the present disclosure has been devised and it is therefore an object of the present disclosure to relatively increase physical feeling to a pressure applied to a forefoot of a foot of a wearer.
In order to achieve the above-described object, a first aspect of the present disclosure relates to a sole for shoes, and the sole includes a sole body, a plurality of lower protrusions arranged at least in a position corresponding to a forefoot of a foot of a wearer in the sole body, each protruding downward from the sole body, and a plurality of upper protrusions arranged at least in a position corresponding to the forefoot of the foot of the wearer in the sole body, each protruding upward from the sole body, each overlapping with an associated one of the plurality of lower protrusions to make a pair of upper and lower protrusions with the lower protrusion in a cross-sectional view. The sole body is configured such that hardness of a portion corresponding to a midfoot of the foot of the wearer is higher than hardness of a portion corresponding to the forefoot of the foot of the wearer.
In the first aspect, each of the upper protrusions overlaps with an associated one of the plurality of lower protrusions to make a pair of upper and lower protrusions with the lower protrusion in a cross-sectional view. Therefore, a reaction force from the ground acts on the lower protrusions and is transferred from the lower protrusions to the wearer's planta via the upper protrusions. Thus, the wearer can recognize differences of pressures transferred to various portions of his or her planta in the respective portions throughout the sole. The sole body is configured such that the hardness of the portion corresponding to the midfoot is higher than the hardness of the portion corresponding to the forefoot. With the above-described configuration, shank breaking is less likely to occur and the pressures transferred from the lower protrusions and the upper protrusions are easily transferred to the planta of the forefoot of the wearer as appropriate. Therefore, according to the first aspect, physical feeling to the pressures transferred to the forefoot of the wearer can be relatively increased.
According to a second aspect of the present disclosure, in the first aspect, the sole body is configured such that a value of bending hardness in the portion corresponding to the midfoot of the foot of the wearer is 0.258 Nm/deg or more.
In the second aspect, the sole body in which shank breaking is less likely to occur can be easily achieved by presetting a lower limit of the bending hardness in the portion of the sole body corresponding to the midfoot.
According to a third aspect of the present disclosure, in the first aspect, an upper surface of the sole body in the position corresponding to the midfoot of the foot of the wearer is formed to be substantially flat.
In the third aspect, the lower protrusions are not provided in the upper surface of the midsole in the position corresponding to the midfoot. Accordingly, stresses are less likely to concentrate in the upper surface. Thus, the bending hardness of the portion of the sole corresponding to the midfoot can be made higher than the bending hardness of the portion of the sole corresponding to the forefoot. As a result, shank breaking can be restrained.
According to a fourth aspect of the present disclosure, in the first aspect, the sole body has an outsole and a midsole arranged on the outsole, and the midsole is configured such that a Young's modulus of a portion corresponding to the midfoot of the foot of the wearer is 0.75 MPa or more.
In the fourth aspect, the bending hardness of the portion of the sole corresponding to the midfoot can be ensured at a level at which shank breaking can be restrained. Accordingly, the physical feeling to the pressures transferred to the forefoot of the wearer can be relatively increased.
According to a fifth aspect of the present disclosure, in the first aspect, a reinforcement body made of a material having higher hardness than the hardness of the sole body is provided in the position corresponding to the midfoot of the foot of the wearer in the sole body, and the reinforcement body extends from a position corresponding to a Lisfranc joint of the foot of the wearer to a position corresponding to a Chopart joint of the foot of the wearer in a foot length direction in the sole body.
In the fifth aspect, with the reinforcement body provided in the portion of the sole body corresponding to the midfoot, the hardness of the portion of the sole body corresponding to the midfoot can be made higher than the hardness of the portion of the sole body corresponding to the forefoot. As a result, shank breaking can be restrained.
A sixth aspect of the present disclosure relates to a sole for shoes, and the sole includes a sole body, a plurality of lower protrusions arranged at least in a position corresponding to a forefoot of a foot of a wearer in the sole body, each protruding downward from the sole body, and a plurality of upper protrusions arranged at least in a position corresponding to the forefoot of the foot of the wearer in the sole body, each protruding upward from the sole body, each overlapping with an associated one of the plurality of lower protrusions to make a pair of upper and lower protrusions with the lower protrusion in a cross-sectional view. The sole body is configured such that a thickness of a portion corresponding to a hindfoot of the foot of the wearer is larger than a thickness of a portion corresponding to the forefoot of the foot of the wearer.
In the sixth aspect, in the sole body, a difference between the thickness of the portion corresponding to the hindfoot and the thickness of the portion corresponding to the forefoot is made, and thus, the foot of the wearer can easily tilt forward. Accordingly, the pressures transferred from the lower protrusions and the upper protrusions are easily transferred to the planta of the forefoot of the wearer as appropriate. Therefore, according to the sixth aspect, physical feeling to the pressures transferred to the forefoot of the wearer can be relatively increased.
According to a seventh aspect of the present disclosure, in the sixth aspect, the sole body is configured such that the difference between the thickness of the portion corresponding to the hindfoot of the foot of the wearer and the thickness of the portion corresponding to the forefoot of the foot of the wearer is 8 mm or more.
In the seventh aspect, the foot of the wearer can be easily maintained in a tilt forward state. As a result, the physical feeling to the pressures transferred to the forefoot of the wearer can be relatively increased.
An eight aspect of the present disclosure relates to a shoe including the sole of the first aspect.
In the eighth aspect, a shoe that exhibits similar advantages to those of the first aspect can be achieved.
A ninth aspect of the present disclosure relates to a shoe including the sole of the second aspect.
In the ninth aspect, a shoe that exhibits similar advantages to those of the second aspect can be achieved.
A tenth aspect of the present disclosure relates to a shoe including the sole of the third aspect.
In the tenth aspect, a shoe that exhibits similar advantages to those of the third aspect can be achieved.
An eleventh aspect of the present disclosure relates to a shoe including the sole of the fourth aspect.
In the eleventh aspect, a shoe that exhibits similar advantages to those of the fourth aspect can be achieved.
A twelfth aspect of the present disclosure relates to a shoe including the sole of the fifth aspect.
In the twelfth aspect, a shoe that exhibits similar advantages to those of the fifth aspect can be achieved.
A thirteenth aspect of the present disclosure relates to a shoe including the sole of the sixth aspect.
In the thirteenth aspect, a shoe that exhibits similar advantages to those of the sixth aspect can be achieved.
A fourteenth aspect of the present disclosure relates to a shoe including the sole of the seventh aspect.
In the fourteenth aspect, a shoe that exhibits similar advantages to those of the seventh aspect can be achieved.
As described above, according to the present disclosure, physical feeling to a pressure applied to a forefoot of a foot of a wearer can be relatively increased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall perspective view of an entire shoe according to a first embodiment.

FIG. 2 is a perspective view of a sole according to the first embodiment illustrating an inner instep side when viewed from above.

FIG. 3 is a plan view of the sole according to the first embodiment.

FIG. 4 is a plan view schematically illustrating the sole according to the first embodiment with a skeleton structure of a foot of a wearer.

FIG. 5 is a bottom view of the sole according to the first embodiment.

FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 3.

FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 3.

FIG. 8 is a cross-sectional view illustrating a cross-sectional structure of the sole taken along the line VIII-VIII in FIG. 3 with the skeleton structure of the foot of the wearer.

FIG. 9 is a view corresponding to FIG. 8 and illustrating a cross-sectional structure of the sole according to a modified example of the first embodiment with the skeleton structure of the foot of the wearer.

FIG. 10 is a view corresponding to FIG. 8 and illustrating a cross-sectional structure of the sole according to a second embodiment with the skeleton structure of the foot of the wearer.

FIG. 11 is a graph illustrating a load ratio of a forefoot region in a sole of each test body.

DETAILED DESCRIPTION

Embodiments of the present disclosure will now be described in detail with reference to the drawings. The following description of the embodiments are mere examples by nature, and are not intended to limit the scope, application, or uses of the present disclosure.

First Embodiment

FIG. 1 illustrates an entire portion of a shoe S according to a first embodiment of the present disclosure. A pair of the shoes S are used, for example, as athletic shoes for running and various sports, sneakers for daily use, or rehabilitation shoes.
The drawings illustrate only a left shoe S as an example. Since a right shoe is symmetrical to the left shoe, only the left shoe will be described in the following description, and the description of the right shoe will be omitted herein.
In the following description, the expressions “upper side” and “lower side” represent the vertical positional relationship between respective portions of the shoe S, the expressions “front (fore)” and “rear (hind)” represent the positional relationship between respective portions of the shoe S in the foot length direction (a longitudinal direction), and the expressions “inner instep side” and “outer instep side” represent the positional relationship between respective portions of the shoe S in a foot width direction. Herein, a “plantar arch” includes both a plantar arch in an inner instep side of a foot f of the wearer and a plantar arch in an outer instep side of the foot f. Furthermore, a “midfoot M” means a region extending from a position of a Lisfranc joint LF of the foot f of the wearer to a position of a Chopart joint CP of the foot in the foot length direction (see FIG. 4 and FIG. 8).

(Upper)

As illustrated in FIG. 1, the shoe S includes an upper 10 that covers the foot f of the wearer. A knit fabric, a woven fabric, a nonwoven fabric, a synthetic leather, an artificial leather, a natural leather, or the like is suitable as a material of the upper 10. The upper 10 is firmly fixed to a peripheral portion 5 of a midsole 4 which will be described later, for example, with an adhesive.
A foot insertion portion 11 in which the foot f of the wearer is inserted is provided in an upper side of the upper 10. An opening portion 12 communicating with the foot insertion portion 11 and extending in the longitudinal direction is formed in an upper side of the upper 10. An eyelet adornment 13 is provided in the opening portion 12. A tongue-piece portion 15 that puts the opening portion 12 in an open state or a close state is provided in a front edge portion of the opening portion 12.
The eyelet adornment 13 is made of, for example, an artificial leather. The eyelet adornment 13 is arranged in a position corresponding to an instep part of the foot f of the wearer in the upper 10. The eyelet adornment 13 is firmly fixed to the upper 10 by sewing. In left and right edge portions of the eyelet adornment 1, eyelet holes 14 are formed so as to be spaced apart from one another in the foot length direction 3.
The upper 10 is provided with a shoe lace 16. The shoe lace 16 can be inserted through the eyelet holes 14 located in the left and right edge portions of the eyelet adornment 13. The upper 10 can be made to fit the instep part of the wearer by fastening both end portions of the shoe lace 16 located in the foot insertion portion 11.

(Sole)

As illustrated in FIGS. 1 to 3, the shoe S has a sole 1. The sole 1 has a sole body 2. The sole body 2 is formed of an outsole 3 and a midsole 4.
The out sole 3 is made of a hard elastic material with higher hardness than that of the midsole 4. Specifically, as a material of the outsole 3, for example, thermoplastic synthetic resins, such as ethylene-vinyl acetate copolymer (EVA) or the like, thermosetting resins, such as polyurethane (PU) or the like, or rubber materials, such as butadiene rubber, chloroprene rubber, or the like are suitable. Note that the hardness of the outsole 3 is preferably set to, for example, 50 A to 80 A in the Asker A scale.
As illustrated in FIGS. 5 to 8, bottomed lower recesses 3 a recessed upward from a lower surface of the outsole 3 in a cross-sectional view. The lower recesses 3 a are arranged substantially in an entire region of the outsole 3 when viewed from the bottom (see FIG. 5).
As illustrated in FIGS. 6 to 8, the midsole 4 is arranged on an upper side of the outsole 3 in a stacked state, for example, with an adhesive. The midsole 4 is made of a soft elastic material with lower hardness than that of the outsole 3. Specifically, as a material of the midsole 4, thermoplastic synthetic resins, such as ethylene-vinyl acetate copolymer (EVA) or the like, foams thereof, thermosetting resins, such as polyurethane (PU) or the like, foams thereof, rubber materials, such as butadiene rubber, chloroprene rubber, or the like, foams thereof, or the like are suitable. Note that the hardness of the midsole 4 is preferably set to, for example, 15 C to 65 C in the Asker C scale.
As illustrated in FIGS. 3, 6, and 7, a peripheral portion 5 is formed to support a peripheral of the planta of the foot f of the wearer in a peripheral of an upper surface of the midsole 4. As illustrated in FIG. 6, bottomed upper recesses 4 a recessed downward from an upper surface of the peripheral portion 5 in a cross-sectional view are formed between the peripheral portion 5 located in an inner instep side and the peripheral portion 5 located in an outer instep side. The upper recesses 4 a are arranged in a position corresponding to a forefoot F of the foot f of the wearer in the midsole 4 when viewed from the top (see FIG. 4).

(Lower Protrusions and Upper Protrusions)

As illustrated in FIGS. 2 to 8, the sole 1 has a plurality of lower protrusions 7 and a plurality of upper protrusions 8. In this embodiment, the lower protrusions 7 are arranged to correspond to the entire planta of the foot f of the wearer in the sole 1 (see FIG. 5). In contrast, the upper protrusions 8 are arranged to correspond to the forefoot F of the foot f of the wearer in the sole 1 (see FIG. 4).
As illustrated in FIG. 5, the lower protrusions 7 are provided in the lower recesses 3 a of the outsole 3. Specifically, as illustrated in FIGS. 6 to 8, each of the lower protrusions 7 protrudes downward from a bottom surface of an associated one of the lower recesses 3 a. Each of the lower protrusions 7 has, for example, a substantially rectangular shape in a cross-sectional view. The lower protrusions 7 are formed to have different thicknesses and different lengths from one another.
As illustrated in FIGS. 2 to 4, the upper protrusions 8 are provided in the upper recesses 4 a of the midsole 4. Specifically, as illustrated in FIG. 6 and FIG. 8, each of the upper protrusions 8 protrudes upward from a bottom surface of an associated one of the upper recesses 4 a. An upper end portion of each of the upper protrusions 8 has, for example, a substantially hemispherical shape. The upper protrusions 8 are formed, for example, to have different thicknesses and different lengths from one another.
As illustrated in FIGS. 6 and 8, each of the upper protrusions 8 is arranged right above an associated one of the lower protrusions 7 in a region of the forefoot F. That is, each of the upper protrusions 8 overlaps with an associated one of the lower protrusions 7 located in the region of the forefoot F to make a pair of upper and lower protrusions with the lower protrusion 7 in a cross-sectional view.

(Hardness of Sole Body)

As a feature structure of this embodiment, the sole body 2 is configured such that hardness of a portion thereof corresponding to a midfoot M of the foot of the wearer is higher than hardness of a portion thereof corresponding to the forefoot F.
Specifically, the sole body 2 is preferably configured such that a value of bending hardness in the portion corresponding to the midfoot M is 0.258 Nm/deg or more. Note that the above-described hardness value is a numerical value that can be obtained in a case where a bending test is performed on the sole body 2 in which a reinforcement body 9 which will be described later is not provided.
Herein, to check whether the sole body 2 has the above-described hardness value, for example, the following measurement method (bending test) is suitable. That is, using an unillustrated general-purpose bending test machine (for example, “Shoe Flexer”, a product manufactured by Exeter Research), a pressing sensor of the test machine is fixed to be pressed against the sole body 2 in a position of the sole body 2 corresponding to the midfoot M of the sole body 2 in which the reinforcement body 9 which will be described later is not provided and, in this fixed state, a rear end portion of the sole body 2 is raised by a predetermined angle (for example, 40 deg) from a horizontal position. At this time, the hardness value output from the bending test machine may be 0.258 Nm/deg or more.
In this embodiment, the upper surface of the midsole 4 in positions corresponding to the midfoot M and a hindfoot H is formed to be substantially flat. That is, in the midsole 4, the upper protrusions 8 are not provided at least in the position corresponding to the midfoot M. Thus, the hardness of a portion of the sole body 2 corresponding to the midfoot M can be relatively increased. It is preferable that a Young's modulus of the portion of the midsole 4 corresponding to the midfoot M is made to be 0.75 MPa or more by forming the upper portion of the midsole 4 in the position corresponding to the midfoot M substantially flat. Note that “substantially flat” as described above expresses not only “completely flat” but also “substantially flat” including “slightly rounded.”

(Reinforcement Body)

As illustrated in FIGS. 3 and 4, the sole body 2 is provided with the reinforcement body 9 that further increases the hardness of the portion corresponding to the midfoot M of the wearer. The reinforcement body 9 is formed of a thin layer with higher hardness than that of those of the outsole 3 and the midsole 4 and is preferably made of a hard elastic material.
Specific examples of the hard elastic material include thermoplastic resins, such as thermoplastic polyurethane (TPU), polyamide elastomer (PAE), ABS resin, or the like, and thermosetting resins, such as epoxy resin, unsaturated polyester resin, or the like. Note that fiber-reinforced plastic (FRP) containing carbon fiber, aramid fiber, glass fiber, or the like as fibers for reinforcement and a thermosetting resin or a thermoplastic resin as a matrix resin may be used.
The reinforcement body 9 has a substantially trapezoidal shape when viewed from the top. Specifically, an outer shape of the reinforcement body 9 has a substantially trapezoidal shape whose side located in the inner instep side has a larger length than a length of a side located in the outer instep side when viewed from the top. That is, the reinforcement body 9 is configured such that, in an arch portion of the foot of the wearer, the hardness is higher in a position corresponding to the arch portion of the inner instep side than in a position corresponding to the arch portion of the outer instep side.
As illustrated in FIGS. 4 and 8, the reinforcement body 9 is arranged to correspond to the midfoot M of the foot of the wearer in the sole body 2. That is, the reinforcement body 9 is arranged behind the upper protrusions 8 in the foot length direction. The reinforcement body 9 extends from a position corresponding to the Lisfranc joint LF of the foot f of the wearer to a position corresponding to the Chopart joint CP of the foot fin the sole body 2 in the foot length direction.
As illustrated in FIGS. 7 and 8, the reinforcement body 9 is formed to have a substantially plate shape. In this embodiment, the reinforcement body 9 has a uniform thickness. The reinforcement body 9 is provided between the outsole 3 and the midsole 4 in a stacked arrangement in a cross-sectional view. Specifically, a lower surface of the reinforcement body 9 is firmly fixed to an upper surface of the outsole 3 and an upper surface of the reinforcement body 9 is firmly fixed to a lower surface of the midsole 4. Note that the thickness of the reinforcement body 9 may not be uniform.

Advantages of First Embodiment

As described above, each of the upper protrusions 8 overlaps with an associated one of the lower protrusions 7 to make a pair of upper and lower protrusions with the lower protrusion 7 in a cross-sectional view. Therefore, a reaction force from the ground acts on the lower protrusions 7 and is transferred from the lower protrusions 7 to the planta of the foot f via the upper protrusions 8. Thus, the wearer can recognize the differences of pressures transferred to various portions of the forefoot F.
In general, when a sole of a shoe contacts the ground during exercise, in a foot of a wearer, a load trajectory (so-called load path) of weight shift that passes from an outer instep side of a heel to a toe via substantially center portions of a hindfoot and a midfoot in a foot width direction and an inner instep side of a forefoot is generated. In the load path, when bending hardness of a portion of the sole corresponding to the midfoot is relatively low, a phenomenon (that is, “shank breaking”) that the portion of the sole corresponding to the midfoot is broken (bent) tends to occur. When this shank breaking occurs, in a course of the above-described load path, in particular, weight shift that passes from the midfoot to the toe is hindered. Thus, a timing of weight shift toward the forefoot of the foot of the wearer is delayed and a weight of the wearer is less likely to be applied to a portion of the sole corresponding to the forefoot. As a result, in a sole of a shoe of a related technology (for example, Japanese Patent Application No. 2019-63491), pressures from lower protrusions and upper protrusions are hardly transferred to the planta in the forefoot of the wearer appropriately.
In contrast, the sole body 2 of this embodiment is configured such that the hardness of the portion corresponding to the midfoot M is higher than the hardness of the portion corresponding to the forefoot F. In this configuration, the above-described shank breaking is less likely to occur. As a result, in particular, the timing of weight shift from the midfoot M to the forefoot F is not delayed in the load path and the weight of the wearer tends to be applied to a portion of the sole 1 corresponding to the forefoot F. Thus, pressures from the lower protrusions 7 and the upper protrusions 8 can be easily transferred to the planta of the wearer in the forefoot F. Accordingly, in the sole 1 according to the first embodiment and the shoe S including the sole 1, the physical feeling to the pressures transferred to the forefoot F of the wearer can be relatively increased.
The sole body 2 is configured such that the value of bending hardness in the portion corresponding to the midfoot M is 0.258 Nm/deg or more. As described above, a lower limit of the bending hardness in the portion of the sole body 2 corresponding to the midfoot M is preset, and thus, the sole body 2 in which shank breaking is not likely to occur can be easily achieved.
The upper surface of the midsole 4 in the position corresponding to the midfoot M is formed to be substantially flat. That is, the lower protrusions 7 are not provided in the upper surface of the midsole 4 in the position corresponding to the midfoot M. Accordingly, stresses are less likely to concentrate in the upper surface. Thus, the bending hardness of the portion of the sole 1 corresponding to the midfoot M can be made higher than the bending hardness of the portion of the sole 1 corresponding to the forefoot F. As a result, shank breaking can be restrained.
The midsole 4 is configured such that the Young's modulus of the portion corresponding to the midfoot M is 0.75 MPa or more. In this configuration, the bending hardness of the portion of the sole 1 corresponding to the midfoot M can be ensured at a level at which shank breaking can be restrained. Accordingly, the physical feeling to the pressures transferred to the forefoot F of the wearer can be relatively increased.
Furthermore, with the reinforcement body 9 provided in the portion of the sole body 2 corresponding to the midfoot M, the hardness of the portion of the sole body 2 corresponding to the midfoot M can be easily made higher than the hardness of the portion of the sole body 2 corresponding to the forefoot F. As a result, shank breaking can be restrained.

First Variation of First Embodiment

In the first embodiment, an embodiment in which the reinforcement body 9 is provided in the sole body 2 is described, but the present disclosure is not limited to this embodiment. For example, as in a variation illustrated in FIG. 9, the reinforcement body 9 may not be provided in the sole body 2.
Even in this variation, the value of bending hardness in the portion of the sole body 2 corresponding to the midfoot M may be 0.258 Nm/deg or more. As another option, the upper surface of the midsole 4 in the position corresponding to the midfoot M may be formed to be substantially flat. As still another option, the Young's modulus of the portion of the midsole 4 corresponding to the midfoot M may be 0.75 MPa or more. That is, in the sole body 2, as long as the hardness of the portion corresponding to the midfoot M is made higher than the hardness of the portion corresponding to the forefoot F, similar to the first embodiment, the physical feeling to the pressures transferred to the forefoot F of the wearer can be relatively increased.

Second Embodiment

FIG. 10 illustrates a sole 1 according to a second embodiment of the present disclosure. In the second embodiment, as compared to the first embodiment, the sole 1 has a different configuration. Note that other than the following differences, a configuration according to the second embodiment is similar to the configuration of the sole 1 according to the first embodiment. Therefore, in the following description, the same component as a corresponding component of in FIGS. 1 to 8 will be denoted by the same reference sign as that of the corresponding component, and detailed description thereof will be omitted.
In this embodiment, a sole body 2 is configured such that a thickness of a portion corresponding to a hindfoot H is larger than a thickness of a portion corresponding to a forefoot F. Specifically, in the sole body 2, a difference between the thickness of the portion corresponding to the hindfoot H and the thickness of the portion corresponding to the forefoot F is preferably set to 8 mm or more. Note that, in the sole body 2 of this embodiment, the reinforcement body 9 described in the first embodiment is not provided.
Specifically, a heel support portion 20 is provided in a position in the sole body 2 corresponding to the hindfoot H which is described in the first embodiment. The heel support portion 20 is made of, for example, the same material as that of a midsole 4. The heel support portion 20 is formed to have a substantially plate shape in a cross-sectional view. The heel support portion 20 preferably has a thickness of 8 mm. A lower surface of the heel support portion 20 is firmly fixed to an upper surface of the midsole 4, for example, with an adhesive.
In this embodiment, in the sole body 2, a difference between the thickness of the portion corresponding to the hindfoot H and the thickness of the portion corresponding to the forefoot F is made, and thus, a foot f of a wearer can easily tilt forward. As a result, in a load path, a timing of weight shift from the hindfoot H to the forefoot F is not delayed and a weight of the wearer tends to be applied to a portion of the sole 1 corresponding to the forefoot F. Thus, pressures from the lower protrusions 7 and the upper protrusions 8 can be easily transferred to the planta of the wearer in the forefoot F, as appropriate. Accordingly, even in this embodiment, the physical feeling to the pressures transferred to the forefoot F of the wearer can be relatively increased.
The sole body 2 is configured such that the difference between the thickness of the portion corresponding to the hindfoot H and the thickness of the portion corresponding to the forefoot F is 8 mm or more. With this configuration, the foot f of the wearer can be easily maintained in a tilt forward state. As a result, the physical feeling to the pressures transferred to the forefoot F of the wearer can be relatively increased.

Other Embodiments

In each of the above-described embodiments, the sole 1 includes the sole body 2 formed of the outsole 3 and the midsole 4, but the present disclosure is not limited thereto. For example, the sole body 2 may be formed of the outsole 3.
In each of the above-described embodiments, the upper protrusions 8 are arranged only in the position of the midsole 4 corresponding to the forefoot F, but the present disclosure is not limited thereto. For example, in the first embodiment and the variation thereof, the upper protrusions 8 may be arranged in both the position of the sole body 2 corresponding to the forefoot F and the position of the sole body 2 corresponding to the hindfoot H. In contrast, in the second embodiment, the upper protrusions 8 may be arranged in the position of the sole body 2 corresponding to the forefoot F and the position of the sole body 2 corresponding to the midfoot M and/or the hindfoot H.
In each of the above-described embodiments, the lower protrusions 7 are arranged substantially in the entire portion of the lower surface of the outsole 3, but the present disclosure is not limited thereto. That is, each of the upper protrusions 8 may overlap with an associated one of the lower protrusions 7 to make a pair of upper and lower protrusions with the lower protrusion 7 in a cross-sectional view, and the lower protrusions 7 may not be arranged substantially in the entire portion of the lower surface of the outsole 3.
In each of the above-described embodiments, the lower protrusions 7 are formed to have different thicknesses and different lengths from one another, but the present disclosure is not limited thereto. That is, the lower protrusions 7 may be formed to have the same thickness and the same length. Similar applies to the upper protrusions 8.
In the first embodiment and the variation thereof, the upper surface of the sole body 2 in the position corresponding to the midfoot M is formed to be substantially flat, but the present disclosure is not limited thereto. That is, when the value of bending hardness in the portion of the sole body 2 corresponding to the midfoot M is 0.258 Nm/deg or more, the upper surface of the sole body 2 in the position corresponding to the midfoot M may not be formed to be substantially flat.
In the first embodiment, the reinforcement body 9 has a substantially trapezoidal shape when viewed from the top, but the present disclosure is not limited thereto. That is, the reinforcement body 9 may have various shapes, such as a circular shape, a triangular shape, a pentagonal shape, or the like when viewed from the top.
In the first embodiment, the reinforcement body 9 is provided between the outsole 3 and the midsole 4 in a stacked arrangement, but the present disclosure is not limited thereto. For example, the reinforcement body 9 may be embedded in the outsole 3 or in the midsole 4. As another option, the upper surface of the reinforcement body 9 may be stacked on the lower surface of the outsole 3. As still another option, the lower surface of the reinforcement body 9 may be stacked on the upper surface of the midsole 4.
In the second embodiment, the reinforcement body 9 described in the first embodiment is not provided in the sole body 2, but the present disclosure is not limited thereto. That is, even in the second embodiment, the reinforcement body 9 can be provided in the sole body 2.
In the second embodiment, the heel support portion 20 formed as one member is provided in the position in the sole body 2 corresponding to the hindfoot H, but the present disclosure is not limited thereto. For example, a member (not illustrated) in which the heel support portion 20 is integrally formed with the sole body 2 may be used. That is, in the second embodiment, as long as a difference between the thickness of the portion corresponding to the hindfoot H and the thickness of the portion corresponding to the forefoot F is made in the sole body 2, whether the heel support portion 20 is formed as a separate member from the sole body 2 does not matter.
Embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above, and various changes and modifications may be made without departing from the scope of the present disclosure.

Examples

Examples of a sole according to the second embodiment described above and a shoe including the sole will be described below. Specifically, a test subject wore four shoe test bodies and the test subject's foot pressure when the test subject wore each of the four shoe test bodies was measured. A load ratio of a portion of the sole corresponding to a forefoot (which will be hereinafter referred to merely as a “load ratio”) was calculated from results of the measurement, and then, calculated load ratios were compared and examined. Note that the present disclosure it not limited to the examples.

[Test Bodies and Measurement Conditions]

In Table 1 blow, major configurations of respective soles applied to the four shoe test bodies used in the measurement and a difference between a thickness of a portion of each of the soles corresponding to the forefoot and a thickness of a portion of the each of the soles corresponding to the hindfoot are illustrated. In Table 1 below, all conditions under which the measurement was performed are illustrated. Note that a member corresponding to the reinforcement body described in the first embodiment is not provided in the soles of the test bodies indicated in Table 1.

TABLE 1

		Difference between
	Major Configurations of Soles	Thicknesses of Portions

		Heel Support	Corresponding to	Load Ratio X
Test Body (Shoes)	Sole Body	Portion	Forefoot and Hindfoot	(%)

No. 1	Sample (1)	None	4 mm	44.3%
(Comparative Example)
No. 2	Sample (1)	Sample (2)	6 mm	44.5%
(Comparative Example)		(Thickness: 2 mm)
No. 3	Sample (1)	Sample (3)	8 mm	50.8%
(Example)		(Thickness: 4 mm)
No. 4	Sample (1)	Sample (4)	10 mm	54.1%
(Example)		(Thickness: 6 mm)

	TABLE 2

	Condition Items	Contents

	Test Subject	One Adult Mail
		(Height: 177.6 cm,
		Weight: 65.4 kg)
	Posture of Test Subject	Static Standing Posture
	during Measurement
	Measurement Position	Left Foot of Test Subject
	Used Device	X4 Foot & Gait
		(Name of Manufacturer:
		XSENSOR)
	Measurement Time	5 seconds
	Sampling Frequency	100 Hz

[Method for Calculating Load Ratio]

Next, a method for calculating the load ratio will be described below.
First, based on foot pressure data obtained by the foot pressure measurement, a position (which will be hereinafter referred to as a “toe position”) in which a toe (a forefoot front end) of a foot of the test subject contacted a sole of each test body and a position (which will be hereinafter referred to as a “heel position”) in which a heel (a hindfoot rear end) of the foot of the test subject contacted the sole of the test body are specified. Thus, a distance (which will be hereinafter referred to as a “foot length distance”) in a foot length direction in the foot of the test subject contacting the sole of each test body is specified. Then, assuming that the foot length distance is 100%, a position separated from the heel position in a forward direction by a distance of 55.8% of the foot length distance is defined as a position of the forefoot rear end in the foot of the test subject. Thus, a region (which will be hereinafter referred to as a “forefoot region”) of the forefoot in the foot of the test subject contacting the sole of each test body is specified.
Second, a first total value A for the foot pressure applied to the forefoot region and a second total value B for the foot pressure applied to a region ranging from the toe position to the heel position are calculated. Then, a load ratio X (%) for the foot pressure applied to the forefoot region is calculated according to an expression X=(A/B)×100. Note that an average value obtained when the above-described measurement continued for five seconds is set as a representative value of the load ratio X (%) in the sole of each test body.

[Comparison and Examination]

The load ratio X (%) of each test body obtained by the above-described measurement is illustrated in Table 1 (see the right column in Table 1) and FIG. 11. With reference to Table 1 and FIG. 11, for test bodies No. 1 and No. 2, the load ratio X is less than 50%. That is, when the difference between the thickness of the portion corresponding to the forefoot and the thickness of the portion corresponding to the hindfoot in the sole was 4 mm and 6 mm, the foot pressure on the forefoot region of the sole was relatively low. In contrast, for test bodies No. 3 and No. 4, the load ratio X is 50% or more. That is, when the difference between the thickness of the portion corresponding to the forefoot and the thickness of the portion corresponding to the hindfoot in the sole was 8 mm or more, the foot pressure on the forefoot region of the sole was relatively high.
According to the comparison and examination, it was found that the foot pressure on the forefoot region of the sole can be made relatively high by configuring the sole body such that the difference between the thickness of the portion corresponding to the hindfoot and the thickness of the portion corresponding to the forefoot in the sole is 8 mm or more. Thus, it was found that, in the shoes (the test bodies No. 3 and No. 4) of the examples, the foot of the test subject (wearer) can be easily maintained in a tilt forward state and the physical feeling to the pressure on the forefoot of the wearer can be relatively increased.
The present disclosure is industrially applicable to, for example, soles applied to sport shoes used in various kinds of sports such as running and ball games, sneakers for daily use, and shoes for rehabilitation, and shoes using the soles.

Claims

What is claimed is:

1. A sole for shoes, comprising:

a sole body;

a plurality of lower protrusions arranged at least in a position corresponding to a forefoot of a foot of a wearer in the sole body, each protruding downward from the sole body; and

a plurality of upper protrusions arranged at least in a position corresponding to the forefoot of the foot of the wearer in the sole body, each protruding upward from the sole body, each overlapping with an associated one of the plurality of lower protrusions to make a pair of upper and lower protrusions with the lower protrusion in a cross-sectional view, wherein

the sole body is configured such that a hardness of a portion corresponding to a midfoot of the foot of the wearer is higher than a hardness of a portion corresponding to the forefoot of the foot of the wearer.

2. The sole of claim 1, wherein

the sole body is configured such that a value of bending hardness in the portion corresponding to the midfoot of the foot of the wearer is 0.258 Nm/deg or more.

3. The sole of claim 1, wherein

an upper surface of the sole body in the position corresponding to the midfoot of the foot of the wearer is formed to be substantially flat.

4. The sole of claim 1, wherein

the sole body has an outsole and a midsole arranged on the outsole, and

the midsole is configured such that a Young's modulus of a portion corresponding to the midfoot of the foot of the wearer is 0.75 MPa or more.

5. The sole of claim 1, wherein

a reinforcement body made of a material having higher hardness than the hardness of the sole body is provided in the position corresponding to the midfoot of the foot of the wearer in the sole body, and

the reinforcement body extends from a position corresponding to a Lisfranc joint of the foot of the wearer to a position corresponding to a Chopart joint of the foot of the wearer in a foot length direction in the sole body.

6. A sole for shoes, comprising:

a sole body;

the sole body is configured such that a thickness of a portion corresponding to a hindfoot of the foot of the wearer is larger than a thickness of a portion corresponding to the forefoot of the foot of the wearer.

7. The sole of claim 6, wherein

the sole body is configured such that a difference between the thickness of the portion corresponding to the hindfoot of the foot of the wearer and the thickness of the portion corresponding to the forefoot of the foot of the wearer is 8 mm or more.

8. A shoe comprising:

the sole of claim 1.

9. A shoe comprising:

the sole of claim 2

10. A shoe comprising:

the sole of claim 3.

11. A shoe comprising:

the sole of claim 4.

12. A shoe comprising:

the sole of claim 5.

13. A shoe comprising:

the sole of claim 6.

14. A shoe comprising:

the sole of claim 7.