Shoe sole

The present application claims priority to and is a national stage application, filed under 35 U.S.C. § 371, of International Application No. PCT/JP2013/077630, filed on Oct. 10, 2013, the contents of which fully incorporated herein by reference in its entirety.

The present invention relates to an improvement to a shoe sole having a structure in which an outsole is arranged under a midsole.

A shoe sole is generally required to be light-weight, durable, gripping, shock-absorbing, bendable, etc., and each of these properties needs to be on a certain level or better while some of them are in a tradeoff relationship. In recent years, there has been a demand for better designing the tread surface of a shoe sole and for taking environmental considerations with a shoe sole.

With court shoes, cross-training shoes, etc., for example, the outsole often covers the entire surface of the midsole in view of the durability and the gripping property. However, an outsole, which is made of a non-foamed rubber material or a rubber material with a small expansion ratio, covering the entire surface of the midsole leads to an increase in the weight of the shoe sole. Conversely, if the midsole is partially exposed for a reduced weight, such exposed portions will generate weaknesses in view of durability.

Patent Literature

First Patent Document: JP05-065201Y (front page)

Second Patent Document: JP01-154805Y (front page)

Third Patent Document: JP63-172302Y (front page)

Fourth Patent Document: JP07-136003A (front page)

An object of the present invention is to provide a shoe sole that can be expected to suppress the durability lowering and to be light-weight, gripping and shock-absorbing, as well as being adequately bendable. Moreover, one can also expect that it accommodates a greater design variety while taking environmental considerations.

A shoe sole of the present invention includes:

an outsole 1 made of a rubber having a tread surface 10 and an upper surface 11 ; and

a mid sole 2 having an upper surface 21 and a lower surface 20 , wherein the lower surface 20 is attached to the upper surface 11 of the outsole 1 , and a main (primary) component of the mid sole 2 is a foam body having a thermoplastic resin component, wherein:

the outsole 1 includes:

a plurality of cleats C 1 arranged while being spaced apart from one another in a first direction D 1 ; and

a plurality of cleats C 1 arranged while being spaced apart from one another in a second direction D 2 crossing (intersecting) the first direction D 1 ;

ones of the cleats C 1 (i.e., the cleats arranged in the first and second directions) that are adjacent to each other in a third direction D 3 crossing the first and second directions are continuous with each other in the third direction D 3 via a first connecting portion 12 of the outsole;

ones of the cleats C 1 (i.e., the cleats arranged in the first and second directions) that are adjacent to each other in a fourth direction D 4 crossing the first, second and third directions D 1 to D 3 are continuous with each other in the fourth direction D 4 via a second connecting portion 13 of the outsole;

a plurality of through holes H are provided, each through hole H being defined in an area surrounded by three or more of the cleats C 1 (i.e., the cleats arranged in the first and second directions); and

the lower surface 20 of the mid sole 2 includes:

an attachment surface 22 attached to the upper surface 11 of the outsole 1 , and an exposed surface 23 of the foam body exposed through the through holes H.

According to the present invention, the through holes H of the outsole 1 and the exposed surfaces 23 are adjacent to each other, each being surrounded by three or more cleats C 1 . Therefore, for each cleat C 1 , the deformation independence of the cleat C 1 is exerted because of the through holes H and the exposed surfaces 23 .

That is, the rigidity (stiffness) of each cleat C 1 is not reinforced by the surrounding outsole 1 or by other cleats C 1 but remains flexible. Therefore, each cleat C 1 easily undergoes a shear deformation and a compressive deformation. This will improve the gripping property for catching the ground (floor) surface, and one can also expect an improvement to the shock-absorbing property.

On the other hand, the through holes H formed in the outsole 1 are helpful in reducing the weight of the outsole 1 .

Now, the midsole 2 and the outsole 1 are joined (integrated) together, by being bonded or welded together, thereby increasing the thickness, thus significantly increasing the rigidity (stiffness) against flexure, i.e., the flexural rigidity EI Z (E: Young's modulus, and I Z : moment of inertia of area). The flexural rigidity EI Z is generally in proportion to the thickness of the sole squared. Therefore, the through holes H formed in the outsole 1 contribute to the lowering of the flexural rigidity EI Z , which will improve the bendability of the shoe sole.

Moreover, since a plurality of through holes H are provided in the outsole 1 , of which the specific gravity is much larger than that of the midsole 2 , it is possible to reduce the weight and it is also more desirable for the environment.

The cleats C 1 of the outsole 1 are continuous with each other in the third direction D 3 and in the fourth direction D 4 via the first connecting portion 12 and the second connecting portion 13 , thus suppressing an increase in the number of components (members) while reducing the weight.

Moreover, the plurality of through holes H are each surrounded by three or more cleats C 1 and are not continuous with each other. Thus, such structure can suppress the lowering of the durability.

The surface of the midsole 2 typically has a different color from the outsole 1 and/or a beautiful texture, and the plurality of exposed surfaces 23 and the outsole 1 forming a contrast in color therebetween will be helpful in increasing the design variety of the shoe sole.

Herein, the outsole 1 made of a rubber is formed by a foamed rubber material (a rubber foam) having a relatively small expansion ratio or a non-foamed rubber material (a non-foam of rubber), and the outsole 1 has a greater specific gravity than the midsole 2 but is superior in wear resistance.

The foam body of the midsole 2 includes a component of the thermoplastic tread surface 10 and any other suitable component. Examples of the thermoplastic resin component may include a thermoplastic elastomer and a thermoplastic resin.

Example types of the thermoplastic elastomer may include a styrene-based elastomer such as styrene-ethylene-butylene-styrene block copolymer (SEBS), and an ethylene-vinyl acetate copolymer (-based) elastomer.

Example types of the thermoplastic resin may include a vinyl acetate-based resin such as ethylene-vinyl acetate copolymer (EVA), polystyrene, and a styrene-butadiene resin. The resin components listed above may be used alone or in combination of two or more.

As used in the present invention, “a main (primary) component being a foam body” means that a half or more of the upper surface 21 or the lower surface 20 of the midsole 2 , or a half or more of the volume of the midsole 2 , is formed by a foam body and that the midsole 2 may partially include gel, pod-like members (pods), and the like.

FIG. 1A is a bottom view of a shoe sole showing one embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line IB-IB of FIG. 1A .

FIG. 2 is a schematic perspective view showing, on an enlarged scale, a main part of the shoe sole of the embodiment.

FIG. 3 is a bottom view of the main part.

FIG. 4A and FIG. 4B are a cross-sectional view taken along line IVA-IVA of FIG. 1A and a cross-sectional view taken along line IVB-IVB of FIG. 1A , respectively.

FIG. 5 is a bottom view showing a relationship between the shoe sole and the foot bone structure.

FIG. 6A and FIG. 6B are schematic bottom views each showing an alternative shape and arrangement of cleats and through holes.

FIG. 7A and FIG. 7B are schematic bottom views each showing an alternative shape and arrangement of cleats and through holes.

FIG. 8A and FIG. 8B are schematic bottom views each showing an alternative shape and arrangement of cleats and through holes.

Preferably, the upper surface 21 of the mid sole 2 is continuous across (over) ones of the plurality of exposed surfaces 23 that are adjacent to each other and the attachment surface 22 attached to the first or second connecting portion 12 , 13 ; and

the outsole 1 is necked (constricted, recessed, or narrowed) as if it were cut out (hollow out, or gouge out) as seen in a plan view at each first or second connecting portion 12 , 13 between cleats C 1 that are adjacent to each other in the third or fourth direction D 3 , D 4 .

In such a case, the outsole 1 is necked as if it were cut out as seen in a plan view at each first or second connecting portion 12 , 13 . This improves the aforementioned deformation independence of the cleats C 1 adjacent to each other. This will further improve the gripping property and the shock-absorbing property.

The necked portions will improve the light-weightness, the bendability, etc.

More preferably, the upper surface 21 of the mid sole 2 is continuous across (over) ones of the plurality of exposed surfaces 23 that are adjacent to each other and the attachment surface 22 attached to the first connecting portion 12 ;

the upper surface 21 of the mid sole 2 is continuous across (over) ones of the plurality of exposed surfaces 23 that are adjacent to each other and the attachment surface 22 attached to the second connecting portion 13 ;

the outsole 1 is necked (constricted, recessed, or narrowed) as seen in a plan view at each first connecting portion 12 between cleats C 1 that are adjacent to each other in the third direction D 3 ; and

the outsole 1 is necked (constricted, recessed, or narrowed) as seen in a plan view at each second connecting portion 13 between cleats C 1 that are adjacent to each other in the fourth direction D 4 .

In such a case, the outsole 1 is necked as if it were cut out (hollow out, or gouge out) as seen in a plan view at each of both the first and second connecting portions 12 and 13 . This will further improve the aforementioned deformation independence of the cleats C 1 adjacent to each other.

Preferably, three or more through holes H are provided, and the cleats C 1 are arranged so that each cleat C 1 is adjacent to the three or more through holes H and the cleat C 1 is surrounded by the three or more through holes H around this cleat.

In such a case, each cleat C 1 is surrounded by through holes H. Therefore, the aforementioned independence of each cleat C 1 will improve.

Preferably, the plurality of exposed surfaces 23 are arranged while being spaced apart from one another in the first direction D 1 and are arranged while being spaced apart from one another in the second direction D 2 ;

ones of the plurality of exposed surfaces 23 that are adjacent to each other in the third direction D 3 are made discontinuous (intermittent) in the third direction D 3 with each other by the second connecting portion 13 of the outsole 1 ; and

ones of the plurality of exposed surfaces 23 that are adjacent to each other in the fourth direction D 4 are made discontinuous (intermittent) in the fourth direction D 4 with each other by the first connecting portion 12 of the outsole 1 .

In such a case, as the exposed surfaces 23 of the midsole 2 are discontinuous with each other, it is possible to suppress the flexural rigidity of the shoe sole becoming locally too small.

Preferably, a level (e.g., height above ground) of the lower surface 14 of the first or second connecting portion 12 , 13 is set to be above the tread surface 10 of the cleats C 1 (i.e., the cleats arranged in the first and second directions).

In such a case, the average thicknesses T 2 and T 3 of the first and second connecting portions 12 and 13 will be smaller than the average thickness T 1 of each of the cleats C 1 , which will improve the aforementioned independence of each cleat C 1 .

Preferably, the plurality of through holes H are provided in a plurality of rows and in a plurality of columns; and

the plurality of exposed surfaces 23 are provided in a plurality of rows and in a plurality of columns.

Rows and columns of through holes H and exposed surfaces 23 will improve the aforementioned independence of the cleats C 1 .

Preferably, a pitch (distance, or frequency) between the plurality of cleats C 1 in each row and in each column is set in a range of 4 to 40 mm; and

a pitch (distance, or frequency) between the plurality of through holes in each row and in each column is set in a range of 4 to 40 mm.

If the pitches are less than 4 mm, the outsole 1 may have a fine mesh-like pattern, which may detract from the aforementioned independence of the cleats.

On the other hand, if the pitches are over 40 mm, the ground contact area of each cleat C 1 increases, and then even if the cleats C 1 appear to be independent of each other, it will detract from the functions derived from the independence.

In view of this, the pitches are more preferably 10 to 40 mm, and most preferably 15 to 35 mm. Note however that there may be some cleats where the pitch therebetween is less than 4 mm or over 40 mm.

Preferably, an opening area (an aperture area) of each of the through holes H is set in a range of 4 to 400 mm 2 .

If the opening area of each through hole H is less than 4 mm 2 , the continuity of the outsole 1 will increase, thereby detracting from the independence of the cleats C 1 .

On the other hand, if the opening area of each through hole H is over 400 mm 2 , there will locally be small-rigidity areas and large-rigidity areas, hindering the stable support of the foot sole.

In view of this, the opening area is preferably 25 to 300 mm 2 , and most preferably 36 to 250 mm 2 . Note however that there may be some through holes H less than 4 mm 2 or over 400 mm 2 .

Preferably, a protruding (projecting) surface 24 protruding downward below (lower than) the attachment surface 22 while being located above (higher than) the tread surface 10 ; and

a non-protruding (non-projecting) surface 25 provided around the protruding surface 24 and being continuous with the attachment surface 22 are included.

In such a case, the protruding surface 24 is formed by the surface of the midsole 2 . This protruding surface 24 will function as a soft cleat.

Moreover, when one steps on a hard projecting object on the through hole H, awkwardness will unlikely be felt on the foot sole.

The amount of dirt or mud to get stuck in the through hole H between the cleats C 1 and C 1 of the outsole 1 will be reduced.

Preferably, the tread surface 10 is protruding in the downward direction below (lower than) the protruding surface 24 by 0.5 to 5 mm.

If the tread surface 10 is protruding in the downward direction past the protruding surface 24 by more than 5 mm, a large amount of dirt may get stuck in the through hole H even with the protruding surface 24 provided.

On the other hand, where the protrusion height by which the tread surface 10 protrudes past the protruding surface 24 is less than 0.5 mm, when the outsole 1 contacts the ground, the protruding surface 24 of the midsole 2 also contacts the ground, in which case the surface of the flexible midsole 2 will likely be scratched, deteriorating the appearance of the shoe sole.

In view of this, these values are preferably 1 to 4 mm, and most preferably about 1.5 to 3 mm.

Preferably, an area of one of the plurality of cleats C 1 (i.e., cleats arranged in the first and second directions) is greater than an area of one of the plurality of protruding surfaces 24 that is adjacent to said one cleat C 1 .

In such a case, the slip-preventing (anti-slip) property from the cleats C 1 will be better exerted. The area of one cleat C 1 means the area surrounded by the outline of the cleat C 1 , of the area surrounded by the plurality of through holes H.

Preferably, an area of one attachment surface 22 to which one of the plurality of cleats C 1 (i.e., cleats arranged in the first and second directions) is attached is greater than an area of one of the plurality of exposed surfaces 23 that is adjacent to said attachment surface 22 .

Where an exposed surface 23 is larger than an adjacent attachment surface 22 , there will be a large area where the rigidity is small. Then, the stable support of the foot sole may be hindered, and awkwardness may more likely be felt when stepping on an object.

Preferably, an area of one attachment surface 22 to which one of the plurality of cleats C 1 is attached is set to 105% to 300% of an area of one of the plurality of exposed surfaces 23 that is adjacent to said attachment surface 22 .

If the area ratio is less than 105%, awkwardness, or the like, may more likely be felt as described above.

On the other hand, if the area ratio is over 300%, the area of the attachment surface 22 for one cleat C 1 will be excessive, in which case the independence discussed above will less likely be exerted even if the cleats appear to be independent of each other.

In view of this, the area ratio between the area of the attachment surface and the area of the exposed surface is preferably 110 to 350%, and most preferably about 120 to 300%.

Preferably, 6 to 60 of the exposed surfaces 23 and 6 to 60 of the cleats C 1 are provided in an intermediate (middle) area α extending between a virtual line L and a calcaneal tuberosity BC, the virtual line L being adjacent to a posterior portion of a ball O 1 of a big toe and extending diagonally forward toward a lateral side of a foot.

In the intermediate area α, as compared to an area anterior or posterior thereto, the outsole 1 is typically less likely to wear out. Therefore, by providing cleats capable of exerting the independence discussed above in the intermediate area α, it is possible to realize the effects discussed above without detracting from the durability of the shoe sole.

Moreover, 6 to 60 exposed surfaces 23 of the midsole 2 will provide a new design for the shoe sole.

In view of the designability, the number of exposed surfaces 23 is preferably 10 to 50, and most preferably about 15 to 45.

Preferably, a Young's modulus of the outsole 1 is greater than a Young's modulus of the midsole 2 .

The hardness of a foamed resin material (foam body of resin) or that of a rubber has a strong correlation with the Young's modulus.

The midsole 2 is typically more flexible than the outsole 1 , and the hardness of the midsole is much smaller than that of the outsole 1 . However, because their hardnesses are measured by using different methods, the concept of Young's modulus is employed instead of their hardness relationship.

Typically, the hardness of the midsole 2 is set to about 40° to 75° in terms of the asker C hardness. On the other hand, the hardness of the outsole 1 is set to about 55° to 70° in terms of the JIS-A hardness. Note that 70° in the JIS-A hardness corresponds to about 86° in the asker C hardness.

The present invention will be understood more clearly from the following description of preferred embodiments taken in conjunction with the accompanying drawings. Note however that the embodiments and the drawings are merely illustrative and should not be taken to define the scope of the present invention. The scope of the present invention shall be defined only by the appended claims. In the accompanying drawings, like reference numerals denote like components throughout the plurality of figures.

An embodiment of the present invention will now be described with reference to the drawings.

The present embodiment is a shoe sole of a shoe for running or walking, for example.

As shown in FIG. 1B , the shoe sole includes the outsole 1 made of a rubber, and the midsole 2 made of a resin. Note that an upper (not shown) wrapping around the instep is provided on the shoe sole.

A primary component of the midsole 2 is a foamed material of EVA, for example, and the midsole 2 may include a reinforcement unit (not shown). The midsole 2 may be provided with a low-resilience material, a high-resilience material, a groove, etc.

The outsole 1 is a tread bottom having a greater wear resistance than the foam body of the midsole 2 , and typically has a greater hardness and a greater Young's modulus than those of the foam body of the midsole 2 . Note that “made of a rubber” herein means that it contains a component of a natural rubber or a synthetic rubber, and may contain any other suitable component.

The outsole 1 includes the tread surface 10 and the upper surface 11 . The midsole 2 includes the upper surface 21 and the lower surface 20 , and the lower surface 20 is attached to the upper surface 11 of the outsole 1 .

The midsole 2 generally covers the entire surface of the foot sole. On the other hand, the outsole 1 of FIG. 1A includes a base portion 1 B, and many cleats C 1 and many through holes H formed on the base portion 1 B. The lower surface 20 of the midsole 2 protrudes through the through holes H, thereby forming many exposed surfaces 23 .

In the present embodiment, a perimeter (circumferential) edge 26 of the outsole 1 is in a continuous loop shape. Many cleats C 1 are provided in the area delimited (surrounded) by the perimeter edge 26 . Moreover, as shown in FIG. 5 , many exposed surfaces 23 and many cleats C 1 are provided in the intermediate area α extending between the virtual line L and the calcaneal tuberosity BC, the virtual line L being adjacent to a posterior portion of the ball O 1 of the big toe and extending diagonally forward toward the lateral side of the foot.

Note that in the present embodiment, for example, the area ratio of the through holes H with respect to the area of the outsole 1 (the open area ratio) is larger on the lateral side La of the foot than on the medial side Me of the foot. Therefore, it is possible to suppress overpronation.

As shown in FIG. 3 and FIG. 2 on an enlarged scale, the outsole 1 includes a plurality of projecting cleats C 1 (one group of cleats) arranged while being spaced apart from each other in the first direction D 1 . Another plurality of cleats C 1 (another group of cleats) are arranged while being spaced apart from each other in the second direction D 2 crossing the first direction D 1 .

The thin base portion 1 B is provided around each cleat C 1 .

Note that in FIG. 3 and in FIG. 6A to FIG. 8B to be discussed later, areas of the outsole 1 where the cleats C 1 are provided are shaded with large dots, whereas the thin base portion 1 B is shaded with fine dots. In FIG. 2 , the thickness of the thin base portion 1 B is represented by the thickness of the line.

In the present embodiment, a plurality of ridges are provided (accommodated) in each cleat C 1 shown in FIG. 3 , whereas each cleat C 1 is shown in FIG. 2 to have a smooth surface instead of having ridges thereon for the sake of illustration.

As shown in FIG. 2 and FIG. 3 , ones of the cleats C 1 that are adjacent to each other in the third direction D 3 crossing the first and second directions D 1 and D 2 are continuous with each other in the third direction D 3 via the first connecting portion 12 of the outsole 1 .

Ones of the cleats C 1 that are adjacent to each other in the fourth direction D 4 crossing the first, second and third directions D 1 to D 3 are continuous with each other in the fourth direction D 4 via the second connecting portion 13 of the outsole 1 .

That is, in the present embodiment, the cleats C 1 , the first connecting portions 12 and the second connecting portions 13 are formed from a single (one sheet of) outsole 1 .

The first and second connecting portions 12 and 13 are each formed by a portion of the base portion 1 B. That is, the level of the lower surface 14 of the first or second connecting portion 12 , 13 is set to be above the tread surface 10 of the cleats C 1 .

The through holes H are each defined in an area surrounded by four of the cleats C 1 . Note that as shown in FIG. 1 and FIG. 3 , some through holes H are each defined by being surrounded by three cleats C 1 and the perimeter edge 26 .

The lower surface 20 of the midsole 2 includes attachment surfaces 22 of FIG. 4A attached to the upper surface 11 of the outsole 1 , and exposed surfaces 23 of a foamed material exposed through the through holes H.

As shown in FIG. 2 and FIG. 3 , the plurality of through holes H are provided in a plurality of rows (preferably in three rows or more) and in a plurality of columns (preferably in three columns or more). Therefore, the plurality of exposed surfaces 23 are provided in a plurality of rows (preferably in three rows or more) and in a plurality of columns (preferably in three columns or more).

Moreover, the plurality of cleats C 1 arranged in the first and second direction are provided in a plurality of rows (columns, lines, queues, or alignments) (preferably in three or more rows) and in a plurality of columns (rows, lines, queues, or alignments) (preferably in three or more columns). Thus, the plurality of cleats C 1 and the plurality of through holes H are arranged alternating with each other in the first direction D 1 , and the plurality of cleats C 1 and the plurality of through holes H are arranged alternating with each other in the second direction D 2 . Thus, the cleats C 1 and the exposed surfaces 23 form a lattice pattern.

As shown in FIG. 4A and FIG. 4B , the upper surface 21 of the midsole 2 is continuous across ones of the plurality of exposed surfaces 23 that are adjacent to each other and the attachment surface 22 attached to the first connecting portion 12 .

As shown in FIG. 1A and FIG. 1B , the upper surface 21 of the midsole 2 is continuous across ones of the plurality of exposed surfaces 23 that are adjacent to each other and the attachment surface 22 attached to the second connecting portion 13 .

As shown in FIG. 1 and FIG. 3 , the outsole 1 is necked as if it were cut out as seen in a plan view at each first connecting portion 12 between cleats C 1 that are adjacent to each other in the third direction D 3 .

The outsole 1 is necked as if it were cut out as seen in a plan view at each second connecting portion 13 between cleats C 1 that are adjacent to each other in the fourth direction D 4 .

Thus, many cleats C 1 with the deformation independence discussed above are molded altogether as an integral piece of a single outsole member, for example.

Note that the meaning of “as seen in a plan view” is generally equal to as seen in a bottom view.

The width W value of each of the connecting portion 12 and 13 is preferably 0.8 to 10 mm, more preferably 1 to 7 mm, and even more preferably 1.5 to 6 mm. In such a case, it is possible to exert the deformation independence of the cleats C 1 , and it will be unlikely that the first and second connecting portions 12 and 13 are cut off when being molded.

As shown in FIG. 1 to FIG. 3 , the plurality of exposed surfaces 23 are arranged while being spaced apart from each other in the first direction D 1 , and are arranged while being spaced apart from each other in the second direction D 2 .

Note that as shown in FIG. 4B , on (along) the upper surface 21 of the midsole 2 , a pair of the exposed surfaces 23 are continuous with each other via the attachment surface 22 .

Ones of the plurality of exposed surfaces 23 that are adjacent to each other in the third direction D 3 are made discontinuous in the third direction D 3 with each other by the second connecting portion 13 of the outsole 1 ; and

ones of the plurality of exposed surfaces 23 that are adjacent to each other in the fourth direction D 4 are made discontinuous in the fourth direction D 4 with each other by the first connecting portion 12 of the outsole 1 .

As shown in FIG. 2 , each exposed surface 23 includes a protruding surface 24 and a non-protruding surface 25 . The protruding surface 24 protrudes in the downward direction below the attachment surface 22 while being located above the tread surface 10 .

The non-protruding surface 25 is provided around the protruding surface 24 and being continuous with the attachment surface 22 .

As shown in an enlarged view of FIG. 4B , the tread surface 10 protrudes in the downward direction below the protruding surface 24 by 0.5 to 5 mm, for example.

As shown in FIG. 3 , in the present embodiment, each of the first and second connecting portions 12 and 13 is formed between corners Cc of adjacent cleats C 1 . Thus, the first and second connecting portions 12 and 13 substantially necked, making it more likely that the aforementioned deformation independence of the cleats C 1 is exerted.

The area of one of the plurality of cleats C 1 is greater than the area of one of the plurality of protruding surfaces 24 that is adjacent to this one cleat C 1 .

The area of one attachment surface 22 to which one of the plurality of cleats C 1 is attached, i.e., the area of one cleat C 1 plus the area of the base portion 1 B around this cleat C 1 , is greater than the area of one of the plurality of exposed surfaces 23 that is adjacent to this attachment surface 22 .

The area of one attachment surface 22 to which one of the plurality of cleats C 1 is attached is set to 105% to 300%, for example, of the area of one of the plurality of exposed surfaces 23 that is adjacent to that attachment surface 22 .

The pitch between the plurality of cleats C 1 in each row and in each column is set in the range of 4 to 40 mm, for example. The pitch between the plurality of through holes in each row and in each column is set in the range of 4 to 40 mm.

The opening area of each through hole H is set in the range of 4 to 400 mm 2 , for example.

Next, alternative (other) embodiments will be described.

The shape of the cleats C 1 may be triangular as shown in FIG. 6A , hexagonal as shown in FIG. 6B , circular as shown in FIG. 7A , or may include different shapes (heteromorphic) as shown in FIG. 7B .

The first and second connecting portions 12 and 13 connecting the cleats C 1 together may not be formed by the base portion 1 B as shown in FIG. 6A . For example, the first and second connecting portions 12 and 13 may each be formed by a corner Cc of a cleat C 1 and a side (straight line or curved line) CL of a cleat C 1 as shown in FIG. 6B , or may each be formed by a curve contacting another curve as shown in FIG. 7A .

Nevertheless, if the first and second connecting portions 12 and 13 are each formed between corners Cc of cleats C 1 as in the embodiments shown in FIG. 2 or FIG. 6A , a substantially necked portion is formed between cleats C 1 and C 1 , making it more likely that the deformation independence of the cleats C 1 is exerted.

Note that in FIG. 6A , locations of the first connecting portion 12 and those of the second connecting portions coincide (overlap) with each other.

In the embodiment of FIG. 8A , each cleat C 1 arranged between two through holes H will exert the independence discussed above. Moreover, cleats C 1 that are adjacent to one through hole H will exert the independence discussed above to some extent. On the other hand, it may be unlikely that any cleat C 2 surrounded by such cleats C 1 exerts the independence discussed above.

Note that in the embodiment of FIG. 8B , the cleats C 1 and the cleats C 2 may have an even lower level of the independence discussed above as compared with FIG. 8A .

While preferred embodiments have been described above with reference to the drawings, various obvious changes and modifications will readily occur to those skilled in the art upon reading the present specification.

For example, small depressed (concave) portions or protruding (convex) portions may be formed on the surface of the cleats, instead of ridges formed in the cleats. Moreover, cleats may be formed in a two-step shape.

The protruding surfaces of the midsole may not be provided in the through holes.

Triangular cleats may be arranged, instead of triangular through holes, along the perimeter edge of the outsole. Cutouts (notches), each of which is surrounded by three cleats, may be provided along the perimeter edge of the outsole.

The outsole and/or the midsole may be formed by a plurality of layers of outsole material (member) and a plurality of layers of midsole material (member), respectively.

Thus, such changes and modifications are deemed to fall within the scope of the present invention, which is defined by the appended claims.

The present invention is applicable to the shoe sole of shoes for a stroll and shoes of daily use, as well as to the shoe sole of athletic shoes, such as running shoes and walking shoes.

1 : Outsole, 10 : Tread surface, 11 : Upper surface, 12 : First connecting portion, 13 : Second connecting portion, 14 : Lower surface

2 : Midsole, 20 : Lower surface, 21 : Upper surface, 22 : Attachment surface, 23 : Exposed surface, 24 : Protruding surface, 25 : Non-protruding surface, 26 : Perimeter edge

BC: Calcaneal tuberosity

C 1 : Cleat, C 2 : Cleat, Cc: Corner, CL: Side

D 1 : First direction, D 2 : Second direction, D 3 : Third direction, D 4 : Fourth direction

H: Through hole

L: Line

O 1 : Ball of big toe

α: Intermediate area