Shoe sole, and shoe provided with shoe sole

A shoe sole, to which an upper member is joined, the shoe sole including a bottom receiving part corresponding to a bottom of the upper member, and a rising part that is formed to rise upwardly from an upper side of the bottom receiving part so as to cover an outer surface of a side of the upper member, wherein the bottom receiving part is formed with vent grooves each recessed in a thickness direction from the upper surface of the bottom receiving part, wherein the rising part is formed with vent holes each penetrating therethrough in a thickness direction of the rising part, and wherein the vent hole is formed to have a vertically elongated shape extending from an upper end side to a lower end side of the rising part, and to be in communication with the vent groove.

FIELD

The present invention relates to a shoe sole having a ventilation structure for ensuring the breathability, and a shoe provided with the shoe sole.

BACKGROUND

Conventionally, there has been provided a shoe configured to draw the air into the shoe, while drawing the air out of the shoe, by means of a ventilation structure formed in a shoe sole thereof.

For example, the shoe disclosed in Patent Document 1 is provided with a shoe sole including a midsole having an elasticity, and a plurality of vent grooves extending in a shoe width direction are formed in an upper side of a rear part of the midsole.

According to the aforementioned shoe sole, the rear part of the midsole is compressed and deformed in the thickness direction when the rear part of the midsole is depressed by the wearer who lands on the heel while walking. The compression and deformation causes the volume of the vent grooves to be reduced, and the air in the vent grooves, that is, the air between the sole of the foot of the wearer and the upper side of the midsole, to be drawn out of the shoe through both ends in the longitudinal direction of each of the vent grooves.

Subsequently, once the depression of the rear part of the midsole is released when the wearer lifts the foot, the shape of the rear part of the midsole is restored. This restoration causes the volume of the vent grooves to be restored, and the air outside the shoe to be drawn into the shoe through the both ends of each of the vent grooves.

The aforementioned shoe sole is thus described to be capable of ensuring the breathability of the sole of the foot of the wearer while walking.

Meanwhile, the entire inside of the shoe, that is, not only the sole of the foot of the wearer, but also the medial and lateral sides of the foot are filled with moisture and heat. Thus, according to the aforementioned conventional shoe sole, the air is likely to stay in the regions proximal to the inside and outside of the foot. Therefore, there is a concern that the comfort of wearing is impaired due to the causes such as stuffiness.

CITATION LIST

Patent Literature

Patent Literature 1: JP 3108843 U

SUMMARY

Technical Problem

In view of the aforementioned circumstances, it is an object of the present invention to provide a shoe sole that can improve the breathability in the shoe, and a shoe that includes the shoe sole.

Solution to Problem

A shoe sole of the present invention is a shoe sole, to which an upper member is joined, the shoe sole comprising a bottom receiving part, to which the upper member is directly or indirectly layered, and a rising part that is formed to rise upwardly from an upper side of the bottom receiving part so as to cover an outer surface of the side of the upper member, wherein the bottom receiving part is formed with at least one vent groove that is recessed in a thickness direction from the upper surface of the bottom receiving part, wherein the rising part is formed with at least one vent hole that penetrates therethrough in a shoe width direction of the shoe sole, and wherein the vent hole is formed to have a vertically elongated shape extending from an upper end side to a lower end side of the rising part, and to be in communication with the vent groove.

The shoe sole of the present invention may be configured such that the vent groove comprises a first vent groove extending straight from the vent hole toward a center in the shoe width direction of the shoe sole, and a pair of second vent grooves branching from a medial end in the shoe width direction of the first vent groove.

In this case, the pair of second vent grooves may be configured such that the distance between the pair of second vent grooves in the shoe longitudinal direction increases, as they advance toward the medial side in the shoe width direction.

The shoe sole of the present invention may be configured such that the rising part comprises a medial rising part that is formed on a medial edge side in the shoe width direction of the bottom receiving part, and a lateral rising part that is formed on a lateral edge side in the shoe width direction of the bottom receiving part, wherein the at least one vent hole is composed of a plurality of vent holes, wherein the plurality of vent holes comprise a medial vent hole formed in the medial rising part and a lateral vent hole formed in the lateral rising part, wherein the at least one vent groove is composed of a plurality of vent grooves, wherein the plurality of vent grooves comprise a medial vent groove that is located on the medial edge side of the bottom receiving part and continued to the medial vent hole, and a lateral vent groove that is located on the lateral edge side of the bottom receiving part and continued to the lateral vent hole, and wherein ends of the pair of second vent grooves included in the medial vent groove and ends of the pair of second vent grooves included in the lateral vent groove are respectively in communication with each other in the shoe width direction.

The shoe sole of the present invention may be configured such that the rising part has an inner surface comprising a joining surface, to which the upper member is joined, and a non-contact surface configured to be in non-contact with the upper member, and wherein the inner surface of the rising part is stepwisely formed so that the joining surface protrudes more on the medial side in the shoe width direction than the non-contact surface.

The shoe sole of the present invention may be configured such that the plurality of vent holes are formed in the rising part at intervals in the shoe longitudinal direction of the shoe sole, and wherein a vertically elongated columnar part extending from a lower end part to an upper end of the rising part is formed by a portion between each adjacent ones of the vent holes in the shoe longitudinal direction.

A shoe of the present invention includes any one of the aforementioned shoe soles, to each of which an upper member is joined.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a shoe sole according to one embodiment of the present invention will be described. In this embodiment, a shoe sole3will be described by taking, for example, a shoe1that includes an upper member2to cover the dorsum of the foot of the wearer and a shoe sole3to which the upper member2is joined, as shown inFIG. 1andFIG. 2.

In this embodiment, the following description will be made by referring to the direction in which the front part and the rear part of the shoe sole3are arranged as the shoe longitudinal direction, referring to the direction corresponding to the width of the shoe sole3as the shoe width direction, and referring to the direction corresponding to the thickness of the shoe sole3as the thickness direction.

The upper member2is configured to cover the foot of the wearer on the shoe sole3. The upper member2according to this embodiment includes a bottom part to be in contact with the sole of the foot of the wearer, and side parts that are continued to the bottom part and cover the sides (a medial side and a lateral side) of the foot of the wearer. A plurality of through holes for ensuring the breathability are formed in the bottom part and the side parts.

The shoe sole3includes a midsole4and an outsole5to be joined to the underside of the midsole4.

The midsole4has an elasticity. As shown inFIG. 3, the midsole4has a bottom receiving part6on which the bottom part of the upper member2is layered, and a rising part7formed to rise from the upper side of the bottom receiving part6so as to cover the outer surface of the side of the upper member2.

In the bottom receiving part6, a plurality of grooves recessed in the thickness direction from the upper surface are formed, and the grooves include vent grooves60extending in the shoe width direction and a longitudinal groove61extending in the shoe longitudinal direction.

Each of the vent grooves60includes a first vent groove62extending from a side edge in the shoe width direction of the bottom receiving part6(a medial edge or a lateral edge in the shoe width direction of the bottom receiving part6) toward a center in the shoe width direction of the bottom receiving part6, and a pair of second vent grooves63branching from one end of the first vent groove62(specifically, one end located close to the center in the shoe width direction of the bottom receiving part6).

The groove width of the first vent groove62(the groove width in the direction orthogonal to the direction in which the center line of the first vent groove62extends) is larger than the groove width of each of the second vent grooves63(the groove width in the direction orthogonal to the direction in which the center line of each of the second vent grooves63extends).

The first vent groove62has a bottom surface including an inclined surface620that is downwardly inclined toward the side edge in the shoe width direction of the bottom receiving part6.

Further, in this embodiment, the distance between the pair of second vent grooves63in the shoe longitudinal direction gradually increases toward the center in the shoe width direction of the bottom receiving part6.

The first vent groove62according to this embodiment extends straight from the side edge of the bottom receiving part6toward the center of the bottom receiving part6. However, for example, both sidewalls in the groove width direction of the first vent groove62may be curved, or may have an uneven surface, provided that the center line of the first vent groove62is formed to extend in the shoe width direction or in the direction intersecting with the shoe width direction.

As shown inFIG. 3, a plurality of vent grooves60are formed at intervals in the shoe longitudinal direction in the bottom receiving part6. More specifically, the plurality of vent grooves60are formed on the side close to the medial edge in the shoe width direction of the bottom receiving part6to be aligned away from each other in the shoe longitudinal direction, and the plurality of vent grooves60are also formed on the side close to the lateral edge in the shoe width direction of the bottom receiving part6to be aligned away from each other in the shoe longitudinal direction. In the following description on this embodiment, the vent groove60on the side close to the lateral edge of the bottom receiving part6may be referred to as a lateral vent groove60, and the vent groove60on the side close to the medial edge of the bottom receiving part6may be referred to as a medial vent groove60.

The first vent grooves62of the vent grooves60adjacent to each other in the shoe longitudinal direction are respectively arranged at intervals in the shoe longitudinal direction as shown inFIG. 4. Therefore, a support64(hereinafter referred to as a first support) for supporting the sole of the foot of the wearer is formed between each adjacent ones of the first vent grooves62aligned in the shoe longitudinal direction.

The second vent grooves63of each of the vent grooves60are formed to be aligned in the shoe longitudinal direction with the second vent groove63of another vent groove60adjacent to the each of the vent grooves60in the shoe longitudinal direction. Therefore, the distance in the shoe longitudinal direction between the second vent groove63of the each of the vent grooves60and the second vent groove63of the other vent groove60decreases toward the center part side of the bottom receiving part6.

Further, in this embodiment, one end of the second vent groove63of each of the vent grooves60(one end located on the side close to the center of the bottom receiving part6) is continued to one end of the second vent groove63of the other vent groove60(one end located on the side close to the center of the bottom receiving part6).

Therefore, a support65(hereinafter referred to as a second support) continued to the first support64is formed between the second vent groove63of the each of the vent grooves60and the second vent groove63of the other vent groove60. The second support65is formed so that the width in the shoe longitudinal direction gradually decreases toward the center of the bottom receiving part6. That is, the second support65is tapered toward the center of the bottom receiving part6.

Further, since the pair of second vent grooves63of each of the vent grooves60branch from one end of the first vent groove62to have a distance in the shoe longitudinal direction increasing therebetween toward the center of the bottom receiving part6as described above, a support (hereinafter referred to as a third support)66is also formed between the pair of second vent grooves63of each of the vent grooves60.

The third support66is formed to have a width in the shoe longitudinal direction gradually increasing toward the center of the bottom receiving part6. The third support66has a medial end660in the shoe width direction extending in the shoe longitudinal direction, and a lateral end661in the shoe width direction having a tapered shape.

The upper surfaces of the first support64, the second support65, and the third support66not only constitute the upper surface of the bottom receiving part6, but also serve as the surface to which the bottom part of the upper member2is layered (joined).

The longitudinal groove61is formed to be open at the front end and the rear end in the shoe longitudinal direction of the shoe sole3. In this embodiment, the longitudinal groove61and the second vent grooves63intersect with each other to thereby form intersection spaces67at the center of the bottom receiving part6.

In this embodiment, the bottom part of the upper member2is directly layered (joined) to the upper surface of the bottom receiving part6. However, it is also possible to indirectly layer (join) the bottom part of the upper member2to the upper surface of the bottom receiving part6.

The upper member2is thermally fused to the bottom receiving part6. For example, in the case where the upper member2is layered on the upper surface of the bottom receiving part6having an adhesive agent applied thereon, the breathability in the shoe1is impaired when the adhesive agent enters any of the vent grooves60. However, when the upper member2is thermally fused to the bottom receiving part6as in this embodiment, the inside of each of the vent grooves60can be used entirely as an air flow path.

As shown inFIG. 5andFIG. 6, the rising part7has a vent hole70penetrating therethrough in the thickness direction.

The vent hole70is formed to have a vertically elongated shape extending from the upper end side to the lower end side of the rising part7. The vent hole70is gradually inclined toward the rear side in the shoe longitudinal direction as it advances from the lower end side to the upper end side.

Further, the lower end of the vent hole70is in communication with the other end of the vent groove60opposite to the aforementioned one end. Therefore, the vent hole70is formed to extend upwardly from an open end of the vent groove60.

The rising part7of this embodiment has a plurality of vent holes70formed to be arranged at intervals in the shoe longitudinal direction.

The inner surface of the rising part7(the surface facing toward the center of the bottom receiving part6) includes a joining surface71to which the upper member2is joined, and a non-contact surface72adjacent to the joining surface71in the shoe longitudinal direction. Further, there is a step between the joining surface71and the non-contact surface72since the joining surface71protrudes more on the medial side in the shoe width direction than the non-contact surface72.

Further, in the rising part7according to this embodiment, a plurality of vertically elongated vent holes70are formed at intervals in the shoe longitudinal direction as described above, and thus a vertically elongated columnar part73extending from the lower end to the upper end of the rising part7is formed between each adjacent ones of the vent holes70in the shoe longitudinal direction as shown inFIG. 1andFIG. 2. That is, in the rising part7, the vent holes70and the columnar parts75are formed to be alternately arranged each other in the shoe longitudinal direction. The lower end of each of the columnar parts73is continued to the upper surface of the bottom receiving part6.

In the shoe sole3according to this embodiment, one rising part7is formed on each of the medial edge side and the lateral edge side in the shoe width direction of the bottom receiving part6.

Therefore, in this embodiment, the following description will be made by referring to the rising part7formed on the medial edge side of the bottom receiving part6as a medial rising part74, referring to the rising part7formed on the lateral edge side of the bottom receiving part6as a lateral rising part74, referring to the vent hole70formed in the medial rising part74as a medial vent hole700, and referring to the vent hole70formed in the lateral rising part75as a lateral vent hole701.

In the medial rising part74according to this embodiment, the maximum height in the thickness direction is set to about 25 mm from the bottom receiving part6, and the height of the medial vent hole700formed near the top of the medial rising part74is set so that an upper end thereof is located at a height of about 15 mm from the bottom receiving part6.

In the lateral rising part74according to this embodiment, the maximum height in the thickness direction is set to about 18 mm from the bottom receiving part6, and the height of the lateral vent hole701formed near the top of the lateral rising part74is set so that an upper end thereof is located at a height of about 8 mm from the bottom receiving part6.

In the rising part7(the medial rising part74, the lateral rising part75) according to this embodiment, the height of the vent hole70is set to, for example, about 30% or more, preferably 40% or more based on the height of the rising part7at a position corresponding to the position at which the vent hole70is formed. It is more preferable that such a height be set to 50% or more in the medial rising part74provided near an inner arch portion that is likely to have a space where moisture or heat inside the shoe1stay due to the skeletal characteristics of the foot.

When the height of the vent hole70from the bottom receiving part6in the rising part7(the medial rising part74, the lateral rising part75) is set to be higher than the thickness of the material that constitutes a bottom surface part of the upper member2(that is, when the vent hole70extends upwardly from the material that constitutes the bottom surface part of the upper member2), the moisture and the heat staying near the bottom edge part inside the shoe1can be easily ventilated therefrom.

For example, when the upper member2is made by the shoemaking method such as the French seam method or the California method, the thickness of the material that constitutes the bottom surface part of the upper member2is generally about 1.5 mm to 3 mm, and thus the height of the vent hole70from the bottom receiving part is preferably set to 4 mm or more. When such a height is set to 8 mm or more, the moisture and the heat staying at the bottom edge portion inside the shoe1can be easily ventilated.

The configuration of the shoe1according to this embodiment is as described above. According to the shoe1of this embodiment, the mutual communication between the vent hole70having a vertically elongated shape extending from the upper end side to the lower end side of the rising part7and the vent groove60formed in the bottom receiving part6(in this embodiment, the medial vent hole700and the vent groove60on the medial edge side of the bottom receiving part6; and the lateral vent hole701and the vent groove60on the lateral edge side of the bottom receiving part6) thus forms a large space (hereinafter, referred to as a ventilation space) on the sides of the edge in the shoe width direction (the medial edge side and the lateral edge side of the bottom receiving part6) of the bottom receiving part6, the large space being in communication with the outside of the shoe sole3and extending from the bottom receiving part6to the upper end side of the rising part7.

Therefore, the shoe1according to this embodiment enables the air to flow smoothly in the vent groove60through the ventilation space, and thereby can produce an excellent effect of improving the breathability inside the shoe1.

Further, the first vent groove62located closer to the medial edge side or the lateral edge side of the bottom receiving part6than to the second vent groove63in the shoe width direction is formed to have a groove width on the upper end side (a groove width in the direction orthogonal to the direction in which the center line of the first vent groove62extends) larger than the groove width on the bottom side (a groove width in the direction orthogonal to the direction in which the center line of the first vent groove62extends), so that a non-contact portion with the sole of the foot of the wearer, namely, the ventilation space, is broadened on the side edge of the bottom receiving part6in the shoe width direction, and therefore the breathability inside the shoe1is further improved.

The bottom surface of the first vent groove62of this embodiment includes the inclined surface620that is inclined downwardly toward the side edge in the shoe width direction of the bottom receiving part6, and thus the ventilation space is also broadened due to this configuration.

According to the shoe sole3of this embodiment, the pair of second vent grooves63are formed closer to the center of the shoe sole3than the first vent groove62, that is, formed in the place where heat and moisture are more likely to stay than in the first vent groove62. However, the air is suppressed from stay in the pair of the second vent grooves63since the pair of second vent grooves63are formed to branch from the inner end of the first vent groove62.

More specifically, the groove width of each pair of second vent grooves63(the groove width in the direction orthogonal to the direction in which the center line of the second vent groove63extends) branched from the inner end of the first vent groove62is smaller than the groove width of the first vent groove62.

Therefore, when the air outside the shoe sole3flows into the second vent groove63through the first vent groove62, the flow speed of the air in the second vent groove63increases, so that the fresh air is easily distributed throughout the inside of the second vent groove63.

The second vent groove63is formed to branch from the inner end of the first vent groove62, so that the volume of the inside thereof is smaller than that of the first vent groove62. Therefore, when the air in the second vent groove63is discharged to the outside of the shoe sole3through the first vent groove62, all the air in the second vent groove63is easily discharged into the first vent groove62without remaining therein.

In this embodiment, since the pair of second vent grooves63is configured to allow a distance therebetween in the shoe longitudinal direction to increase toward the center in the shoe width direction of the shoe sole3, the distribution area of the pair of second vent grooves63is large.

Further, in this embodiment, a plurality of medial vent grooves60are formed to be aligned in the shoe longitudinal direction on the medial edge side in the shoe width direction of the bottom receiving part6, in which each of the plurality of medial vent grooves60includes a first vent groove62extending from the side edge in the shoe width direction of the bottom receiving part6toward the center in the shoe width direction of the bottom receiving part6, and a pair of second vent grooves63branching from the inner end of the first vent groove62with a distance therebetween in the shoe longitudinal direction increasing toward the center in the shoe width direction of the bottom receiving part6.

Thus, on the medial edge side in the shoe width direction of the bottom receiving part6, a plurality of supports64each formed between each adjacent ones of the first vent grooves62in the shoe longitudinal direction and a plurality of second supports65each continued to the inner side (the center part side of the shoe sole3) of each corresponding one of the first supports64are aligned at intervals in the shoe longitudinal direction. Thus, it is possible to suppress a decrease in cushioning properties while improving the breathability.

A third support66having a tapered outer end661is formed between each adjacent ones of the second supports65tapered toward the center of the shoe sole3. That is, the second supports65and the third supports66are alternately arranged in the shoe longitudinal direction on the medial edge side in the shoe width direction of the bottom receiving part6to increase the number of support positions for the sole of the foot to thereby effectively suppress the decrease in cushioning properties.

Similarly, on the lateral edge side in the shoe width direction of the bottom receiving part6, a plurality of the first supports64and a plurality of the second supports65each continued to the inner side of each corresponding one of the first supports64are aligned at intervals in the shoe longitudinal direction, and the second supports65and the third supports66are alternately arranged in the shoe longitudinal direction. Thus, it is possible to effectively suppress a decrease in cushioning properties while improving the breathability.

Further, according to the shoe sole3of this embodiment, the inner surface of the rising part7is stepwisely formed so that the joining surfaces71protrude more on the medial side in the shoe width direction than the non-contact surfaces72, and therefore gaps are formed between the upper member2and thus formed escaping surfaces, and the gaps are opened to the outside by the vent holes70. Accordingly, the gaps allowing the air to flow therethrough are formed between the lateral side of the foot and the inner side of the rising part7, and thereby the breathability on the lateral side of the foot can be improved.

In the rising part7of this embodiment, a plurality of vertically elongated vent holes70are formed at intervals in the shoe longitudinal direction, and thus a vertically elongated columnar part75extending from the lower end part to the upper end of the rising part7is formed by a portion between each adjacent ones of the vent holes70in the shoe longitudinal direction. Thus, a plurality of columnar parts75are also formed in the rising part7to be arranged at intervals in the shoe longitudinal direction, to thereby increase the breathability of the rising part7, while suppressing the decrease in the stiffness of the rising part7by the plurality of columnar parts75.

Further, since the plurality of columnar parts75of the shoe sole3according to this embodiment can suppress the decrease in the stiffness of the rising part7even without taking measures such as separately attaching a reinforcing member to the rising part7, ease of manufacturing can be achieved.

The shoe sole and the shoe of the present invention are not limited to the aforementioned embodiment, and it is matter of course that various modifications can be made without departing from the gist of the present invention.

In the aforementioned embodiment, the vent holes70are formed respectively in the medial rising part74and the lateral rising part75, but the present invention is not limited to this configuration. The vent holes70may be formed in at least one of the medial rising part74and the lateral rising part75.

In the aforementioned embodiment, the rising part7is formed on the medial edge side of the bottom receiving part6and the lateral edge side of the bottom receiving part6, but the rising part7may be formed on at least one of the medial edge side and the lateral edge side.

In the aforementioned embodiment, the medial vent groove60and the lateral vent groove60are formed to face each other in the shoe width direction, but the present invention is not limited to this configuration. For example, the medial vent groove60and the lateral vent groove60may be formed to face each other in a direction inclined with respect to the shoe width direction.

In the aforementioned embodiment, the vent grooves60are formed on each of the medial edge side of the bottom receiving part6and the lateral edge side of the bottom receiving part6, but the vent grooves60may be formed on at least one of the medial edge side and the lateral edge side. The number of the vent grooves60formed to be aligned in the shoe longitudinal direction can be appropriately determined.

Although not specifically mentioned in the aforementioned embodiment, the vent grooves60may be formed on the foot front side or the foot rear foot side with respect to the rising part7.

In the aforementioned embodiment, each pair of second vent grooves63are configured to have a distance therebetween in the shoe longitudinal direction of the shoe sole3increasing toward the center in the shoe width direction of the shoe sole3, but the present invention is not limited to this configuration. For example, each pair of second vent grooves63may be formed to be parallel to each other.

In the aforementioned embodiment, the pair of second vent grooves63of each of the vent grooves60is discontinuous with each other, but the present invention is not limited to this configuration. For example, the pair of second vent grooves63of each of the vent grooves60may be continuous with each other through their one ends on the center in the shoe width direction of the shoe sole3.

In the aforementioned embodiment, each of the vent holes70is inclined gradually toward the rear side in the shoe longitudinal direction as it advances from the lower end side to the upper end side, but may be formed to extend straight upward, or may be inclined gradually toward the front side in the shoe longitudinal direction as it advances from the lower end side to the upper end side.

In the aforementioned embodiment, each of the vent holes70(the medial vent hole700, the lateral vent hole701) is linearly formed, but the present invention is not limited to this configuration. For example, as shown inFIG. 7, each of the vent holes70may have a bent shape (that is, a shape having a bent portion between the lower end and the upper end) or a curved shape. The rising part7may be formed with both of the linear vent hole(s)70having a linear shape and the vent hole(s)70having a bent shape or a curved shape.

In the aforementioned embodiment, each of the vent holes70(the medial vent hole(s)700and the lateral vent hole(s)701) are formed to have an opening width in the shoe longitudinal direction constant or substantially constant from the lower end part to the upper end, but the present invention is not limited to this configuration. For example, the opening width of each of the vent holes70in the shoe longitudinal direction may vary between the lower end and the upper end.

More specifically, for example, each of the vent holes70may be formed so that the opening width of the center (the center in the longitudinal direction of the vent hole70) is larger than the opening width at the upper end or the lower end as shown inFIG. 8, or may be formed so that the opening width at the center is smaller than the opening width at the upper end or the lower end as shown inFIG. 9.

In each of the vent holes70, the opening width at the upper end may be different from the opening width at the lower end, and for example, the opening width may gradually increase as it advances from the upper end to the lower end, or the opening width may gradually decrease as it advances from the upper end to the lower end. Further, the rising part7may be formed with both the vent hole(s)70having a constant or substantially constant opening width and the vent hole(s)70having a non-constant opening width.

Although not specifically mentioned in the aforementioned embodiment, one side of the upper end defining each of the vent holes70and one side of the lower end defining each of the vent holes70may be set to be parallel or substantially parallel to each other, or may be set so that the direction in which one side of the upper end extends and the direction in which one side of the lower end extends intersect with each other. Further, one side defining the vent hole70on the front side in the shoe longitudinal direction and one side defining the vent hole70on the rear side in the shoe longitudinal direction may be set to be parallel or substantially parallel to each other, or may be set to intersect with the direction in which the one side of the front side extends with the direction in which the one side of the rear side extends.

Although not specifically mentioned in the aforementioned embodiment, each of the sides defining the vent hole70may be linear or curved.

REFERENCE SIGNS LIST