Sole Structure for a Shoe and Method for Manufacturing the Same

Abstract

A sole structure includes a sole body. The sole body is a resin-made box-shaped member with a predetermined thickness and an interior space that is defined by an upper wall portion disposed on an upper side, a lower wall portion disposed on a lower side and spaced apart from the upper wall portion, and a pair of sidewall portions disposed between and interconnecting the upper wall portion and the lower wall portion in a heel region or a forefoot region that respectively corresponds to a heel portion or a forefoot portion of a foot of a shoe wearer. The sidewall portions are elastically deformable in a vertical direction and have a plurality of solid or hollow ribs that extend in a substantially vertical direction between the upper wall portion and the lower wall portion.

Claims

1. A sole structure for a shoe having a heel region or a forefoot region that is adapted to respectively correspond to a heel portion or a forefoot portion of a foot of a wearer, at least in said heel region or said forefoot region, said sole structure comprising: an upper wall portion disposed on an upper side; a lower wall portion disposed on a lower side and spaced apart from said upper wall portion; and a pair of sidewall portions disposed between and interconnecting said upper wall portion and said lower wall portion, wherein said upper wall portion, said lower wall portion, and said sidewall portions form a resin-made box-shaped member with a predetermined thickness and having an interior space formed therein, wherein said sidewall portions are elastically deformable in a vertical direction and have a plurality of solid or hollow protrusions that extend continuously in a substantially vertical direction between said upper wall portion and said lower wall portion.

2. The sole structure according to claim 1, wherein said sidewall portions have a round shape that protrudes sideways between said upper wall portion and said lower wall portion.

3. The sole structure according to claim 1, wherein said protrusions are provided on a medial side and a lateral side of said sidewall portions in said heel region or in a ball-of-the-foot part of said forefoot region.

4. The sole structure according to claim 1, wherein said protrusions are disposed along an entire perimeter of said sidewall portions in said heel region or said forefoot region.

5. The sole structure according to claim 1, wherein said protrusions extend to a lower surface of said lower wall portion and a bottom surface of said protrusions forms a ground contact surface along with said lower surface of said lower wall portions.

6. The sole structure according to claim 1, wherein said lower wall portion includes a tapered part or a round part that extends gradually upwardly toward said sidewall portions in said heel region or medial and lateral sides of said forefoot region.

7. The sole structure according to claim 1, wherein said sidewall portions have a heel counter portion that extend upwardly above an upper surface of said upper wall portion in said heel region and that are disposed along a circumference of said heel region.

8. The sole structure according to claim 7, wherein said heel counter portion includes a plurality of solid or hollow protrusions that extend continuously in a substantially vertical direction.

9. The sole structure according to claim 1, wherein said sole structure includes a vent hole in connection with said interior space.

10. The sole structure according to claim 9, wherein there are provided two or more vent holes and each of said vent holes pierces through either one or more wall portions of said upper wall portion, said lower wall portion and said sidewall portion.

11. The sole structure according to claim 9, wherein said vent hole is in connection with said interior space through said hollow protrusion.

12. The sole structure according to claim 11, wherein said hollow protrusion is opened at an upper end.

13. The sole structure according to claim 1, wherein a three-dimensional elastic fiber structure formed of resin fibers is disposed in said interior space.

14. The sole structure according to claim 13, wherein said three-dimensional elastic fiber structure along with said upper and lower wall portions and said sidewall portions is formed by additive manufacturing.

15. The sole structure according to claim 14, wherein said additive manufacturing is a fused deposition modeling.

16. A method for manufacturing a sole structure for a shoe according to claim 1 comprising: a wearer data acquisition process for acquiring foot data of at least said heel portion or said forefoot portion of said foot of said shoe wearer and personal data including weight of said shoe wearer; a sole designing process for designing a thickness of said upper and lower wall portions and said sidewall portions, a shape of said box-shaped member, a size, structure and array pitch of said protrusions, and a three-dimensional elastic fiber structure, based on the foot data and personal data acquired in said wearer data acquisition process; and a forming process for forming by additive manufacturing said box-shape member and said three-dimensional elastic fiber structure designed in said sole designing process.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] For a more complete understanding of the invention, reference should be made to the embodiments illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention.

[0031] FIG. 1 is a general top perspective medial-side view of a shoe (for a right foot) employing a sole structure according to an embodiment of the present invention, viewed from diagonally behind.

[0032] FIG. 2 is a medial side view of the shoe of FIG. 1.

[0033] FIG. 3 is a heel rear end view of the shoe of FIG. 1.

[0034] FIG. 4 is a top plan view of the shoe of FIG. 1.

[0035] FIG. 5 is a bottom view of the shoe of FIG. 1.

[0036] FIG. 6 is a general top perspective lateral-side view of the sole structure of FIG. 1 in the state that an upper is removed from the shoe of FIG. 1, viewed from diagonally behind.

[0037] FIG. 7 is a medial side view of the sole structure of FIG. 6, corresponding to FIG. 2.

[0038] FIG. 8 is a heel rear end view of the sole structure of FIG. 6, corresponding to FIG. 3.

[0039] FIG. 8A illustrates a variant of FIG. 8.

[0040] FIG. 8B illustrates another variant of FIG. 8.

[0041] FIG. 9 is a top plan view of the sole structure of FIG. 6, corresponding to FIG. 4.

[0042] FIG. 10 is a bottom view of the sole structure of FIG. 6, corresponding to FIG. 5.

[0043] FIG. 11 is a cross sectional schematic view of FIG. 9, 10 (or 17) taken along line XI-XI illustrating the state in which a wearer's foot is placed on the sole structure.

[0044] FIG. 12 illustrates the state in which at the time of impacting the ground an impact load is imparted on a heel region of the sole structure of FIG. 11.

[0045] FIG. 13 shows a variant of FIG. 11, illustrating the state in which a wearer's foot is placed on the sole structure.

[0046] FIG. 14 illustrates the state in which at the time of impacting the ground an impact load is imparted on the heel region of the sole structure of FIG. 13.

[0047] FIG. 15 shows another variant of FIG. 11, illustrating the state in which the wearer's foot is placed on the sole structure.

[0048] FIG. 16 illustrates the state in which at the time of impacting the ground an impact load is imparted on the heel region of the sole structure of FIG. 15.

[0049] FIG. 17 is a cross sectional schematic view of FIG. 11 taken along line XVII-XVII

[0050] FIG. 18 shows a variant of FIG. 17.

[0051] FIG. 19 shows the state in which a resin-fiber-made three-dimensional elastic fiber structure is provided in an interior space of the sole structure of FIG. 17.

[0052] FIG. 20 shows the state in which a resin-fiber-made three-dimensional elastic fiber structure is provided in an interior space of the sole structure of FIG. 18.

[0053] FIG. 21 is a partial top perspective view of the three-dimensional elastic fiber structure of FIGS. 19, 20, viewed from diagonally above.

[0054] FIG. 22 shows a variant of the three-dimensional elastic fiber structure of FIG. 21.

[0055] FIG. 23 shows another variant of the three-dimensional elastic fiber structure of FIG. 21.

[0056] FIG. 24 is a top plan schematic view of a basic module constituting the three-dimensional elastic fiber structure of FIG. 23.

[0057] FIG. 24A is a top plan schematic view of a first pattern of the basic module that is arranged at a topmost layer (a first layer) of the basic module of FIG. 24.

[0058] FIG. 24B is a top plan schematic view of a second pattern of the basic module that is arranged at a lower layer (a second layer) immediately adjacent to the first layer of the basic module of FIG. 24.

[0059] FIG. 24C is a top plan schematic view of a third pattern of the basic module that is arranged at a lower layer (a third layer) immediately adjacent to the second layer of the basic module of FIG. 24.

[0060] FIG. 24D is a top plan schematic view of a fourth pattern of the basic module that is arranged at a lower layer (a fourth layer) immediately adjacent to the third layer of the basic module of FIG. 24.

[0061] FIG. 25 is a flow chart illustrating an example of a manufacturing process of the sole structure for the shoe according to the present invention.

[0062] FIG. 26 is a general top perspective medial-side view of a variant of the sole structure of FIG. 6, viewed from diagonally ahead.

[0063] FIG. 26A is a cross sectional view of FIG. 26, showing the position of the vent holes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0064] The present invention will now be described in detail with reference to embodiments thereof as illustrated in the accompanying drawings.

[0065] Referring to the drawings, FIGS. 1 to 10 show a sole structure and a shoe for the sole structure according to an embodiment of the present invention. Here, a running shoe is taken for an example as a shoe. In the following explanation, “upward (upper side/upper)” and“downward (lower side/lower)” designate an upward direction and a downward direction, respectively, or vertical direction of the shoe, “forward (front side/front)” and “rearward (rear side/rear)” designate a forward direction and a rearward direction, respectively, or longitudinal direction of the shoe, and “a width or lateral direction” designates a crosswise direction of the shoe. For example, in the case where a bottom of the shoe is placed on a horizontal plane as shown in FIGS. 2 and 7, “upward” and “downward” generally designate “upward” and “downward” in FIGS. 2 and 7, respectively, “forward” and “rearward” generally designate “left to right direction” in FIGS. 2 and 7, respectively, and “a width direction” generally designates “out of the page” and “into the page” of FIGS. 2 and 7, respectively.

[0066] As shown in FIGS. 1 to 5, Shoe 1 includes a sole structure 2 and an upper 3 provided on the sole structure 2 to cover a foot of a shoe wearer. The sole structure 2 has a heel region H, a midfoot region M and a forefoot region F that correspond to a heel portion, a midfoot portion (or plantar arch portion) and a forefoot portion of the foot, respectively. The sole structure 2 extends longitudinally from a heel rear end to a tiptoe portion and extends laterally from a medial side to a lateral side. In this exemplification, the upper 3 is a sock-type upper in which the entire upper including an access opening is formed of stretchable knit fabric, thus improving fitting property relative to the foot.

[0067] As shown in FIGS. 6 to 10, the sole structure 2 includes a sole body 20 that has the heel region H, the midfoot region M and the forefoot region F. The sole body 20 has a foot sole contact surface 20a on a top surface thereof that comes into direct contact with or indirect contact via an insole (not shown), etc. with the foot sole of the wearer. The foot sole contact surface 20a preferably forms a curved surface that gently curves along the longitudinal direction so as to follow the contour of the shape of the foot sole of the wearer.

[0068] There is provided a heel counterpart 21 mainly at the heel region H of the sole body 20, which is disposed above the sole body 20 and extends along the perimeter of the heel region H. The heel counter part 21 extends upwardly from the foot sole contact surface 20a of the sole body 20 so as to surround and support the circumference of the heel portion of the foot of the wearer, thus improving landing stability at the time of a heel impact. The shoe 1 is so structured as to fixedly attach the lower part of the upper 3 to the foot sole contact surface 20 and the heel counter part 21 via bonding and the like.

[0069] On the bottom surface 20b of the sole body 20, a number of protrusions 20bp of a pillar-shape are provided (see FIG. 5), which are integral with the bottom surface 20b. In this exemplification, as a pillar-shaped protrusion 20bp, a solid cylindrical protrusion of a circular cross sectional shape is used. However, a cross sectional shape of the protrusion 20bp is not restricted to a circle or round. An elliptical or oval cross sectional shape, alternatively, a polygonal cross sectional shape such as hexagonal, octagonal or the like may be used.

[0070] On an outer circumference of the sole body 20, a plurality of ribs (or protrusions) 20p are provided that continuously extend in a pillar-shape in the substantially vertical direction. In this exemplification, the ribs 20p are disposed at an area extending from the heel region H through the midfoot region M to the forefoot region F on both the medial side and the lateral side of the sole body 20, disposed along the perimeter of the heel rear end of the heel region H and the perimeter of the tiptoe part of the forefoot region F. That is, the ribs 20p are provided around the entire perimeter of each region of the heel region H, the midfoot region M and the forefoot region F. Also, in this exemplification, as a rib 20p, a solid cylindrical or hemi-cylindrical protrusion of a circular or semi-circular cross sectional shape is used. However, a cross sectional shape of the rib 20p is not restricted to a circle or semi-circle. An elliptical or oval cross sectional shape, alternatively, a polygonal cross sectional shape such as hexagonal, octagonal or the like may be used.

[0071] As shown in FIG. 7, in this exemplification, the rib 20p extends generally in the vertical direction in an area extending from an anterior part of the heel region H through the midfoot region M to a posterior part of the forefoot region F, inclines gradually forwardly toward the rear side in an area extending from an anterior part of the heel region H to the heel rear end, and inclines gradually rearwardly to the front side in an area extending from an posterior part of the forefoot region F to the tiptoe part. To sum up, the extending direction of the rib 20p is substantially vertical direction in this specification. Also, as shown in FIG. 8, the rib 20p extends generally vertically, viewed from the heel rear end side. Similarly, on an outer circumference of the heel counter part 21, a plurality of ribs (or protrusions) 20p′ are provided that extend substantially vertically in a pillar-shape.

[0072] As shown in FIG. 11, a cross sectional view of FIGS. 9 and 10 taken along line XI-XI, the sole body 20 has an upper wall portion 20A disposed on an upper side, a lower wall portion 20B disposed on a lower side and spaced away from the upper wall portion 20A, and a pair of right and left sidewall portions 20C, 20D that extend substantially in the vertical direction between the upper wall portion 20A and the lower wall portion 20B, that are coupled to the upper wall portion 20A and the lower wall portion 20B, and that extend substantially in the longitudinal direction along the outer peripheries of the upper wall portion 20A and the lower wall portion 20B. FIG. 11 shows an example of a cross section of the sole body 20 passing through the ribs 20p of the sidewall portions 20C, 20D and the pillar-shaped protrusions 20bp of the lower wall portion 20B. In FIG. 11, the heel counter part 21 is omitted. Also, hatching for designating a section is omitted in FIG. 11 for illustration purpose.

[0073] The upper and lower wall portions 20A, 20B and the sidewall portions 20C, 20D form a resin-made box-shaped member, and thus the sole body 20 has a box-structure (or an outer-shell structure). Inside the sole body 20, there is formed an interior space S, or an enclosed space, that is surrounded, enclosed and sealed by the wall portions 20A, 20B, 20C and 20D. Such a hollow box-structure is formed not only in the heel region H but also in the midfoot region M and the forefoot region F of the sole body 20, such that thereby the shape retaining characteristics are maintained all over the sole body 20. As resin for forming the sole body 20, for example, thermo plastic resin like nylon, polyester, TPU (thermo plastic polyurethane), PU (polyurethane) and the like or rubber is used.

[0074] The upper and lower wall portions 20A, 20B and the sidewall portions 20C, 20D have a predetermined thickness t, respectively. The thickness t is preferably set to not less than 1 mm and not more than 3 mm. In FIG. 11 and FIG. 17, a cross sectional view of FIG. 11 taken along line XVII-XVII, the inside of the ribs 20p and the pillar-shaped protrusions 20bp is hollow for weight reduction. Similarly, the inside of the ribs 20p′ is hollow, too. The ribs 20p extend downwardly below the lower surface 20b of the lower wall portion 20B. The bottom surfaces of the ribs 20p along with the bottom surfaces of the pillar-shaped protrusions 20bp form the ground contact surface that comes into contact with the ground. Also, as shown in FIG. 17, preferably, an inequality d>e is satisfied, wherein a diameter of the rib 20p, or semicylindrical protrusion, is set to d, and an interval between the adjacent ribs 20p is set to e.

[0075] A top surface of the upper wall portion 20A constitutes the foot sole contact surface 20a. Here, the foot sole contact surface 20a is formed of a concavely curved surface. A lower surface 20b of the lower wall portion 20B is formed with a number of pillar-shaped protrusions 20bp. The sidewall portions 20C, 20D are provided elastically deformable in the vertical direction and preferably have a round shape respectively that protrudes outwardly sideways or laterally outwardly. The round shape of the sidewall portions 20C, 20D extends to the heel rear end side in the heel region H and a heel rear end surface of the sidewall portions 20C, 20D also has a round shape (see FIG. 7). The above-mentioned ribs 20p are provided along the entire perimeter of the sidewall portions 20C, 20D and have a round shape that protrudes outwardly along the round shape of the sidewall portions 20C, 20D. The ribs 20p continuously extend in the vertical direction without being disconnected between the upper wall portion 20A and the lower wall portion 20B. In addition, the above-mentioned heel counter part 21 (FIGS. 7, 8) is so structured as to extend the sidewall portions 20C, 20D in the heel region H upwardly beyond the upper surface (that is, the foot sole contact surface 20a) of the upper wall portion 20A.

[0076] As mentioned above, since the sole structure 2 has a sole body 20 that is formed in a box-shape by the upper and lower wall portions 20A, 20B and the sidewall portions 20C, 20D (see FIG. 11), when the load is imparted from the foot P at the time of impacting the ground, as shown in FIG. 12, the interior space S of the sole body 20 is compressive-deforms and the sidewall portions 20C, 20D elastically deforms in the vertical direction, thereby exhibiting cushioning property.

[0077] Especially, in this case, since the sidewall portions 20C, 20D have a round shape that protrudes laterally outwardly between the upper and lower wall portions 20A and 20B, the sidewall portions 20C, 20D are easy to deform laterally outwardly at the time of impacting the ground and to return to its original position, thus improving cushioning property of the sidewall portions 20C, 20D. Also, since the sole body 20 is formed by the box-shaped member with a predetermined thickness t, at the time of elastic deformation of the sidewall portions 20C, 20D, the upper and lower wall portions 20A, 20B restrain compressive deformation of the sidewall portions 20C, 20D, thus improving landing stability. Moreover, the sole body 20 is so structured as to form the resin-made upper and lower wall portions 20A, 20B and sidewall portions 20C, 20D in a box-shape, thus simplifying the structure and decreasing the manufacturing cost.

[0078] Furthermore, since the sidewall portions 20C, 20D have a plurality of ribs 20p that continuously extend substantially in the vertical direction between the upper and lower wall portions 20A, 20B, such ribs 20p can increase rigidity of the sidewall portions 20C, 20D thus improving durability of the sidewall portions 20C, 20D and thus the entire sole structure. Also, the amount of the elastic deformation of the sidewall portions 20C, 20D can be adjusted by the ribs 20p, such that thereby cushioning property and stability of the sidewall portions 20C, 20D and thus the entire sole structure can be controlled.

[0079] Moreover, the ribs 20p extend to the lower surface 20b of the lower wall portion 20B and the bottom surface of the rib 20p constitutes the ground contact surface along with the lower surface 20b of the lower wall portion 20B. In this case, since the lower surface 20b of the lower wall portion 20B constitutes the ground contact surface, there is no need to provide a ground contact surface separately from the lower wall portion 20B, thus causing the entire sole structure to be simplified. Also, sine the bottom surface of the rib 20p constitutes the ground contact surface, skid-proof capacity and grip performance of the ground contact surface can be improved, an area of the entire ground contact surface can be enlarged, and landing stability can be enhanced.

First Alternative Embodiment

[0080] In the above-mentioned embodiment, an example was shown in which the sole body 20 extends from the heel region H through the midfoot region M to the forefoot region F (see FIGS. 6 to 10), the sole body 20 has only to be disposed at least at the heel region H or at the forefoot region F. That is, the sole body 20 may be disposed only at the heel region H, only at the forefoot region F, only in an area extending from the heel region H to the midfoot region M, or only in an area extending from the forefoot region F to the midfoot region M.

Second Alternative Embodiment

[0081] In the above-mentioned embodiment, an example was shown in which the ribs 20p are provided along the entire perimeter of the sidewall portions 20C, 20D in an area extending from the heel region H through the midfoot region M to the forefoot region F, i.e. over the whole length of the shoe (see FIGS. 6 to 10), the application of the present invention is not restricted to such an example. The ribs 20p may be provided at the entire perimeter or its portion (e.g. only the medial and lateral side area, etc.) of the sidewall portion 20C and/or 20D only in the heel region H. Since the heel region H is a region where the load is applied at the time of the heel impact, provision of the ribs 20p at the sidewall portions 20C, 20D on the medial and lateral sides of the heel region H can effectively increase the rigidity of the sole structure 2 relative to the heel impact thus effectively improving durability.

[0082] Also, the ribs 20p may be provided at the entire perimeter or its portion (e.g. only the medial and lateral side area or only the ball of the foot area, etc.) of the sidewall portion 20C and/or 20D only in the forefoot region F. The ball of the foot area is shown in the hatched area Bf of FIG. 9 in the above-mentioned embodiment and it is a region that includes mainly a thenar eminence and a hypothenar eminence of the foot and their peripheral areas. The ribs 20p may be provided only at the medial side area Bf.sub.1 and/or the lateral side area Bf.sub.2 of the ball of the foot area Bf. Since the ball of the foot area Bf is a region where a large load is applied at the time of impacting on the forefoot region F, provision of the ribs 20p at the sidewall portions 20C, 20D on the medial and lateral sides of the ball of the foot area Bf can effectively increase the rigidity of the sole structure 2 relative to the forefoot impact thus improving durability effectively.

Third Alternative Embodiment

[0083] In the above-mentioned embodiment, the arrangement direction of the ribs 20p was explained using FIGS. 7 and 8, but the arrangement direction is not limited to the direction described in those drawings. The ribs 20p may be arranged in a direction different from the direction of FIGS. 7 and 8, and alternatively, the ribs 20p may be inclined in the same direction. Also, in the above-mentioned embodiment, an example was shown in which the ribs 20p are arranged at a generally constant pitch in the longitudinal direction, but the application of the present invention is not restricted to such an example. By varying the length of the arrangement pitch, for example, the arrangement pitch may be shortened to dispose the ribs 20p densely in the heel region H, the ball of the foot area Bf, and the midfoot region M, alternatively, the arrangement pitch may be lengthened to dispose the ribs 20p sparsely in the other regions. Moreover, in the above-mentioned embodiment, an example was shown in which the diameter d of each of the ribs 20p is generally the same, but the diameter d of the rib 20p may not be the same.

Fourth Alternative Embodiment

[0084] In the above-mentioned embodiment, an example was shown in which provision of a plurality of ribs 20p′ on the outer circumference of the heel counter part 21 disposed above the sole body 20 increases the rigidity of the heel counter part 21 and improves holdability of the heel portion of the foot during exercise (see FIGS. 6 to 9), but as shown in FIG. 8A, these ribs 20p′ can be omitted. Also, as shown in FIG. 8B, the heel counter part 21 per se may not be provided.

Fifth Alternative Embodiment

[0085] In the above-mentioned embodiment, an example was shown in which the lower surface 20b of the lower wall portion 20B (or the bottom surface of the rib 20p and the pillar-shaped protrusion 20bp) extends generally linearly in the sole width direction (see FIGS. 11 and 12, cross sectional view of the sole body 20), but the application of the present invention is not restricted to such an example. The sole body 20 according to the present invention may have a cross sectional shape as shown in FIGS. 13 to 16. In these drawings, the ribs 20p and the pillar-shaped protrusions 20bp are not illustrated for illustration purposes and the upper and lower wall portions 20A, 20B and the sidewall portions 20C, 20D are shown in bold.

[0086] An example shown in FIG. 13 differs from the above-mentioned embodiment in that there are formed tapered parts 20B.sub.1 on the medial and lateral sides of the lower wall portion 20B that extend gradually upwardly toward the sidewall portions 20C, 20D. In this case, when the load is imparted from the foot P at the time of impacting the ground, as shown in FIG. 14, since the tapered parts 20B.sub.1 sink downwardly, the sidewall portions 20C, 20D are easy to elastically deform downwardly thus exhibiting higher cushioning property.

[0087] An example shown in FIG. 15 differs from the above-mentioned embodiment in that there are formed round parts 20B.sub.2 on the medial and lateral sides of the lower wall portion 20B that extend gradually upwardly toward the sidewall portions 20C, 20D. In this case, when the load is imparted from the foot P at the time of impacting the ground, as shown in FIG. 16, since the round parts 20B.sub.2 deform to sink downwardly (or to be more flattened), the sidewall portions 20C, 20D are easy to elastically deform downwardly thus exhibiting higher cushioning property.

Sixth Alternative Embodiment

[0088] In the above-mentioned embodiment, an example was shown in which the ribs 20p are hollow (see FIG. 17), but the application of the present invention is not limited to such an example. As shown in FIG. 18, the ribs 20p may be solid. Similarly, in the above-mentioned embodiment, an example was shown in which the pillar-shaped ribs 20bp are hollow (see FIG. 11, 12), but the pillar-shaped ribs 20bp may be solid. The ribs 20p′ may be also solid.

Seventh Alternative Embodiment

[0089] In the above-mentioned embodiment, an example was shown in which the interior space S of the sole body 20 is hollow, but the application of the present invention is not restricted to such an example. As shown in FIGS. 19 and 20, there may be provided in the interior space S a three-dimensional elastic fiber structure 5 that is formed of resin fiber (or resin filaments). As shown in FIGS. 19 and 20, the three-dimensional elastic fiber structure 5 is a filament structure in which a number of unidirectionally extending resin filaments 5a are arranged and spaced apart in parallel on a horizontal plane and a number of resin filaments 5b intersecting with (e.g. extending generally perpendicular to) the resin filaments 5a are arranged and spaced apart in parallel on the horizontal plane to form one resin layer on the horizontal plane, and such resin layer is then overlayed in the vertical direction to form a multiple of resin layers.

[0090] The three-dimensional elastic fiber structure 5 is preferably molded (formed/3D-printed) by additive manufacturing, preferably through a 3D printer. As a 3D printer, FDM (Fused Deposition Modeling)-method type is preferably used. This method utilizes thermoplastic resin such as nylon, polyester, TPU (thermo plastic polyurethane), PU (polyurethane), thermoplastic elastomer and the like, or rubber and the like, as with the sole body 20. A soft material is preferable and a soft material having the Asker A hardness of 90 A or below is more preferable. In this case, the three-dimensional elastic fiber structure 5 becomes a soft filament structure.

[0091] When forming the three-dimensional elastic fiber structure 5, the sole body 20 is also formed at the same time. That is, at the time of forming the sole body 20 composed of the upper and lower wall portions 2A, 2B and the sidewall portions 2C, 2D, the three-dimensional elastic fiber structure 5 to be disposed inside the sole body 20 is integrally formed with the sole body 20 (i.e. simultaneously printed with the sole body 20), thereby eliminating a working process for disposing the three-dimensional elastic fiber structure 5 in the interior space S of the sole body 20 to fixedly attach the three-dimensional elastic fiber structure 5 to the sole body 20 thus reducing a manufacturing cost. Preferably, at the time of forming the sole body 20, the heel counter part 21 is also integrally formed with the sole body 20 (i.e. simultaneously printed with the sole body 20), such that thereby forming the sole structure 2 at a time by the additive manufacturing through the 3D printer, thus simplifying the manufacturing process and further reducing the manufacturing cost. Moreover, at the time of forming the sole body 20, if forming is conducted based on foot information such as three-dimensional foot data (e.g. foot length, foot width, arch height, foot sole shape, etc.), foot pressure distribution and the like acquired from individual shoe wearers, personal-fit soles that are customized to fit the feet of the individual shoe wearers can be achieved.

[0092] In this case as well, at the time of impacting the ground, when the load is imparted to the sole body 20 from the foot P of a shoe wearer (see FIG. 12), the internal space S is compressive-deformed and the sidewall portions 2C, 2D are elastically compressive-deformed in the downward direction. Thus, cushioning properties can be improved, and a soft landing can be achieved. Also, at the time of elastic deformation of the sidewall portions 20C, 20D, the upper and lower wall portions 20A, 20B restrain a compressive deformation of the entire sole structure, such that thereby not only landing stability can be improved but also a compressive deformation of the entire sole structure can be adjusted by an elastic deformation of the three-dimensional elastic fiber structure 5 disposed in the interior space S. In such a way, cushioning property and stability of the sole structure 2 can be made compatible

Eighth Alternative Embodiment

[0093] The construction of the three-dimensional elastic fiber structure 5 is not restricted to the construction shown in the seventh alternative embodiment, but various constructions can be adopted.

[0094] In an example shown in FIG. 21, there is formed a gap between the vertically adjacent resin filaments. In an example shown in FIG. 22, there is no gap formed between the vertically adjacent resin filaments, vertically extending wall members are provided, and a number of wall members are intersected with each other. In an example shown in FIG. 23, a resin layer composed of resin filaments arranged in a polygonal-shape on the horizontal plane is vertically overlayed to be multiple layers.

[0095] FIG. 24 is a top plan schematic view to explain a basic module 50 constituting the three-dimensional elastic fiber structure 5 shown in FIG. 23. Different basic modules other than this module are conceivable, but the basic module 50 is taken as an example for convenience sake apart from a manufacturing process. The basic module 50 is composed of a first pattern 51 disposed at a topmost layer (a first layer) and shown by a solid line (see FIG. 24A), a second pattern 52 disposed at a second lower layer immediately adjacent the first layer and shown by a dash-and-dot-line (see FIG. 24B), a third pattern 53 disposed at a third lower layer immediately adjacent the second layer and shown by a double dotted line (see FIG. 24C), and a fourth pattern 54 disposed at a fourth lower layer immediately adjacent the third layer and shown by a dotted line (see FIG. 24D). The first to fourth patterns 51 to 54 are formed of resin filaments (resin fibers). A resin filament with a diameter of for example 0.3 to 0.5 mm may be used.

[0096] As shown in FIG. 24A, the first pattern 51 has a pair of octagonal frame bodies 51a spaced away from each other and a square frame body 52a disposed between the frame bodies 51a. Opposite sides of the frame body 52a are shared with the sides of the frame bodies 51a. As shown in FIG. 24B, the second pattern 52 has a pair of square frame bodies 51b spaced away from each other and chamfered at every apex and a square frame body 52b disposed between the frame bodies 51b. Opposite sides of the frame body 52b are shared with the sides of the frame bodies 51b. As shown in FIG. 24C, the third pattern 53 has a pair of square frame bodies 51c spaced away from each other and a square frame body 52c disposed between the frame bodies 51c and chamfered at every apex. Opposite sides of the frame body 52c are shared with the sides of the frame bodies 51c. As shown in FIG. 24D, the fourth pattern 54 has a pair of square frame bodies 51d spaced away from each other and an octagonal frame body 52d disposed between the frame bodies 51d. Opposite sides of the frame body 52d are shared with the sides of the frame bodies 51d.

[0097] The first to fourth layers of the three-dimensional elastic fiber structure 5 are so structured as to dispose the first to fourth patterns 51 to 54 to cover and spread in each layer. The three-dimensional elastic fiber structure 5 is so structured as to overlay the first to fourth layers in the vertical direction and to contact and attach the vertically adjacent layers with each other via the resin filaments. Also, with regard to regions below the fourth layer, from the third pattern 53 to the second pattern 52 in order, and thereafter the first to fourth patterns 51 to 54 are repeated in ascending order and descending order.

[0098] In such a manner, in the three-dimensional elastic fiber structure 5, the thin resin filaments extend laterally and longitudinally at predetermined spaces to form each layer in a horizontal plane. Then, each layer is overlaid to be connected to each other through the filaments in the vertical (i.e. thickness) direction to constitute a three-dimensional fiber structure 5. Therefore, in every direction as well as longitudinal, lateral and vertical directions, favorable elasticity can be achieved and dramatic weight-reduction is made possible compared to prior-art material such as EVA, rubber and the like.

[0099] Next, an example of a manufacturing process of the sole structure 2 containing the above-mentioned three-dimensional fiber structure 5 will be explained using a flowchart shown in FIG. 25.

[0100] The flowchart is processed in accordance with a program that was pre-installed into a memory (not shown) of for example, a personal computer.

[0101] When the program starts, at step S1 of FIG. 25, a wearer's data is acquired that includes foot data of at least the heel portion or the forefoot portion of the foot of the shoe wearer and a personal data of wearer's weight, etc. Such foot data may include three-dimensional foot data (e.g. foot length, foot width, arch height, foot sole shape, etc.), foot pressure distribution and the like. Such personal data may include a wearer's running style (e.g. a heel-striker-type, midfoot-striker-type, or a forefoot-striker-type) in addition to his/her weight.

[0102] Then, at step S2, a sole structure is designed based on the wearer's data acquired at step S1. In this process, in addition to a size and shape of the sole; a thickness (e.g. 1 mm) of an upper wall portion, a lower wall portion and a sidewall portion constituting the sole; a shape of the box-shaped member; a size (e.g. 3 mm in diameter), structure (e.g. solid/hollow) and an array pitch of the protrusions; and a three-dimensional elastic fiber structure inside the sole are designed. When designing the three-dimensional elastic fiber structure, not only static information on a standing posture of the shoe wearer but also dynamic information (e.g. tendency for pronation/supination, etc.) on for example, running may be considered. Then, at step S3, the sole and the three-dimensional elastic fiber structure that have been designed at step S2 are formed/3D-printed by additive manufacturing, preferably through a 3D printer. In addition, during forming by a 3D printer, a horizontal posture in which the bottom surface of the sole structure is disposed on the horizontal plane may be employed, and alternatively, a standing posture in which the heel rear end surface of the sole structure is disposed on the horizontal plane such as a vertical or oblique posture may be employed.

[0103] According to the present invention, since the sole and the three-dimensional elastic fiber structure disposed therein are designed based on the shoe wearer's data including the actual foot data and personal data of the wearer, a personal-fit sole structure that is customized according to individual feet of the shoe wearers can be achieved. Also, since the sole and the three-dimensional elastic fiber structure are formed integrally with (simultaneously printed with) each other by the additive manufacturing, preferably through a 3D printer, a manufacturing cost can be decreased.

Ninth Alternative Embodiment

[0104] FIG. 26 shows an alternative embodiment of the present invention, which corresponds to FIG. 6 in the above-mentioned embodiment. As shown in FIG. 26, on the foot sole contact surface 20a of the sole body 20, there is formed one or a plurality of vent holes 20h.sub.1 in connection with the interior space S. Likewise, on the outer circumferential surface, there is formed one or a plurality of vent holes 20h.sub.2 in connection with the interior space S. As shown in FIG. 26A, the vent holes 20h.sub.1 pass through the upper wall portion 20A, and the vent holes 20h.sub.2 pass through the sidewall portion 20D. The lower wall surface 20B has one or a plurality of vent holes 20h3 formed therethrough in connection with the interior space S. FIG. 26A shows a cross section of FIG. 26, but the whole vent holes are shown in one cross sectional view for illustration purposes. Also, an upper end of the hollow ribs 20p is opened so that an opening at the upper end can function as a vent hole 20h4. At this time, the vent hole 20h4 provides a connection with the interior space S through an inner passage of the hollow ribs 20p.

[0105] There is no need to provide all these vent holes 20h.sub.1, 20h.sub.2, 20h.sub.3 and 20h.sub.4. At least either one of the vent holes 20h.sub.1, 20h.sub.2, 20h.sub.3 and 20h.sub.4 may be provided. Therefore, at least one vent hole may be provided at least at either one of the upper wall portion 20A, the lower wall portion 20B, the sidewall portion 20C/20D or the rib 20p.

[0106] According to this embodiment, at the time of compressive-deformation of the sole body 20, air in the interior space S is discharged to the outside through the vent hole (in this case, the vent hole acts as a discharge hole), whereas at the time of returning deformation of the sole body 20, the outside air is introduced into the interior space S through the vent hole (in this case, the vent hole acts as an intake hole). Therefore, in the event that for example, the foot sole contact surface 20a has the vent hole 20h.sub.1 formed therethrough in the forefoot region F and the heel region H has the vent hole 20h.sub.1 formed therethrough, at the time of impacting the ground at the heel region H, when the interior space S of the heel region H compressive-deforms, air in the interior space S of the forefoot region F is discharged through the vent hole 20h.sub.1 at the forefoot region F to the outside, thus ventilating the inside of the forefoot region F. Then, as the load is transferred to the forefoot region F, when the interior space S at the forefoot region F compressive-deforms, air in the interior space S of the heel region H is discharged through the vent hole 20h.sub.1 at the heel region H to the outside, thus ventilating the inside of the heel region H.

[0107] As for the vent hole 20h.sub.4, since the vent hole 20h.sub.4 is disposed outside the upper of the shoe, entry of a fresh outside air into the inside of the upper can be facilitated. Also, since the vent hole 20h.sub.4 is disposed at an upper end of the sole structure 2, entry of soil, sand, water or the like into the upper can be prevented. In addition, the upper end of the vent hole 20h.sub.4 does not need to be opened at the time of molding the rib 20p. When molding the rib 20p, the upper end of the vent hole 20h.sub.4 is kept closed, and thereafter the upper end may be opened by cutting or heat-melting the upper end through a postprocessing.

Other Application

[0108] In the above-mentioned embodiments and alternative embodiments, an example was shown in which the sole structure of the present invention was applied to the running shoe, but the application of the present invention is not limited to such an example. The present invention also has application to walking shoes, other sports shoes or shoes including sandals.

[0109] As mentioned above, the present invention is useful for a sole structure for a shoe that can not only improve cushioning property and stability with a simplified structure but also enhance durability.

[0110] Those skilled in the art to which the invention pertains may make modifications and other embodiments employing the principles of this invention without departing from its spirit or essential characteristics particularly upon considering the foregoing teachings. The described embodiments and examples are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. Consequently, while the invention has been described with reference to particular embodiments and examples, modifications of structure, sequence, materials and the like would be apparent to those skilled in the art, yet fall within the scope of the invention.