Shoe sole

Abstract

To provide a sole that can totally support a phase from contact with a ground to start elevation of a heel so as to be capable of promoting a forefoot running method more naturally during running and maintaining more longer time.SOLUTION: When L represents a distance to a toe tip position Se from an original point O which is measured along a sole upper surface 20, where the original point O is a rearmost end position So of the sole upper surface 20; C represents an intersection point between a line passing through a position of 0.45×L from the original point O along the sole upper surface 20 and orthogonal to a reference line S and a sole lower surface 31; and D represents an intersection point between a line passing through a position of 0.60×L from the original point O and orthogonal to the reference line S and the sole lower surface 31; the sole lower surfaces 31 in a heel part and a toe part are separated from a ground surface R at a stable posture in which a sole 1 comes into contact with the ground surface R at the point C and the point D; and θ represents an angle defined by a straight line T connecting between a heel center position 20h in a position of 0.15×L from the original point O and a metatarsophalangeal joint position 20j in a position of 0.68×L and the ground surface R, a sole is set to θ≥5°in the stable posture.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to shoe soles, and more particularly to an improved structure that fully supports the phase from contact with the ground to the start of heel lift, so as to more naturally encourage a forefoot sprint while running and make it more sustainable. [Background technology]

[0002] In recent years, forefoot running, in which the foot lands on the forefoot, has become mainstream for efficient long-distance running. Forefoot running has the advantage of reducing the burden on the knees and shortening the time the foot is on the ground, easing the burden on the muscles. It is believed that forefoot running can achieve efficient movement and excellent running economy by making good use of the spring-like behavior of the Achilles tendon and calf muscles (i.e., muscle contraction / relaxation and Achilles tendon stretching and contraction). Here, running economy is an index of how little energy (oxygen intake) is required to run at a certain speed, and the better (i.e., higher) the running economy, the less oxygen is consumed and the more efficient the running is.

[0003] However, a certain level of skill is required to master the forefoot running technique. Specifically, first, ground contact skills are required to be able to land on the forefoot / midfoot just before the foot strikes the ground, and secondly, leg strength (muscle strength and endurance) is required to prevent the heel from dropping (descent) and withstand the stretching of the muscles and tendons during the ground contact phase, as well as the need to lock the ankle. Therefore, it is not easy for beginner runners to master the forefoot running technique, and whether they can continue to use the forefoot running technique is mainly dependent on the runner's ability.

[0004] Incidentally, soles incorporating a high-rigidity plate (e.g., a CFRP plate) are in practical use to support the heel when the heel drops in. In such soles, when the load is transferred to the forefoot, the forefoot part of the plate is pushed downward, and the heel part of the plate is lifted upward by a seesaw effect, thereby supporting the heel.

[0005] However, such soles with built-in plates are not configured to naturally encourage a forefoot running style as a sole alone, and are insufficient to make a forefoot running style sustainable.

[0006] Therefore, the applicant of the present application has proposed a shoe sole for realizing the forefoot running style as shown in JP 2020-163084 A (see paragraphs

[0020] to

[0024] ,

[0028] to

[0030] , and FIG. 9 in the same publication). In this sole, the position of the rear end of the surface on the sole contact side is set as the origin, the distance to the position of the tip of the toes measured along the surface on the sole contact side is set as L, and the bottom surface of the heel on the surface on the sole contact side is arranged parallel to the horizontal plane. In this state, the sole thickness at a position Sh that is 0.16×L from the origin is set as h, the sole thickness at a position Sm2 that is (0.3 to 0.5)×L is set as m2, the sole thickness at a position Sm1 that is (0.4 to 0.6)×L (however, m1 is arranged forward of Sm2) is set as m1, and the sole thickness at a position Sf that is 0.7×L is set as f. Then, m2≧m1 and m1≧f and When the relational equation m1≧h is satisfied, and θ1 is the angle that the line connecting position Sm1 and position Sh makes with the horizontal plane, Sm1' is the position where a vertical line drawn from position Sm1 intersects with the ground contact surface, and Sh' is the position where a vertical line drawn from position Sh intersects with the ground contact surface, and θ2 is the angle that the line connecting position Sm1' and position Sh' makes with the horizontal plane, the relational equation θ2≧θ1 is satisfied, and the ground contact surface has a downwardly convex curved shape at the forefoot.

[0007] According to the sole described in the above publication, the sole thickness h at the position Sh, which is 0.16×L from the origin, is smaller than the sole thickness m1 at the position Sm1, which is (0.4-0.6)×L from the origin, and the angle θ2 between the line connecting the position Sm1' and the position Sh' and the horizontal plane is larger than the angle θ1 between the line connecting the position Sm1 and the position Sh and the horizontal plane, so that the heel does not touch the ground when landing, preventing heel strike and promoting ground contact at the forefoot when landing. Also, the sole thickness m2 at the position Sm2 is larger than the sole thickness m1 at the position Sm1, so that when the sole initially touches the ground at the position Sm1' on the sole ground contact surface, the sole is prevented from tilting backward and the heel from dropping downward, and the sole can quickly transition to rolling forward after the initial contact. Furthermore, the sole thickness f at position Sf, which is 0.7×L from the origin, is smaller than the sole thickness m1 at position Sm1, and the sole contact surface has a downwardly convex curved shape at the forefoot, which allows the sole to roll forward smoothly. Summary of the Invention [Problem to be solved by the invention]

[0008] The inventors of the present invention have further conducted intensive research into soles that enable the forefoot running style, and as a result, have discovered the following facts. When focusing on the first half of the running phase from initial contact with the ground to when the heel begins to lift, it is up to the runner to decide whether the sole tilts forward (i.e. rolls) or backwards (i.e. rolls) at initial contact with the ground. If it tilts backwards, the heel drops and the center of gravity that has moved toward the heel must be moved back toward the forefoot, resulting in not only a loss of time and power, but also a loss of foot posture, causing discomfort to the runner and leading to foot fatigue.

[0009] Therefore, it was found that conventional soles are not yet sufficient to allow more people to experience forefoot running, and that there is room for further improvement in the soles described in the above publication in order to encourage a more natural forefoot running style while running and to fully support the forefoot running style in an even more sustainable way.

[0010] The present invention has been made in consideration of the above-mentioned conventional situation, and the problem that the present invention aims to solve is to provide a shoe sole that can fully support the phase from contact with the ground to the start of heel lift, so as to encourage a more natural and sustainable forefoot running style when running. [Means for solving the problem]

[0011] The sole of the shoe according to the present invention extends from the heel to the toe, has a sole upper surface and a sole lower surface, and has a reference line S, a straight line connecting the rear end position of the sole upper surface and the position of the tip of the toe, the rear end position being the origin O, and the distance from the origin O to the position of the tip of the toe measured along the sole upper surface being L, and the intersection point C between the line that passes from the origin O along the sole upper surface and passes through a position of 0.45×L and intersects with the reference line S at right angles and the sole lower surface, and a distance C between the origin O along the sole upper surface and a position of 0.60×L. When the intersection point between the line passing through position and perpendicular to reference line S and the underside of the sole is defined as D, and a sole posture in which the sole touches the ground at points C and D is defined as a stable posture, in the stable posture, the underside of the sole at the heel and toe is away from the ground, and θ is the angle that a straight line connecting the heel center position, which is 0.15 × L from the origin O along the top surface of the sole, and the metatarsophalangeal joint position, which is 0.68 × L from the origin O, makes with the ground, θ is set to be ≥ 5° in the stable posture. Also, when the intersection point E is the line that passes from the origin O along the sole upper surface and passes through the position of 0.70×L and intersects with the reference line S at right angles with the sole lower surface, the sole is in contact with the ground at points C, D, and E in the stable posture, point E is located on the medial edge of the sole lower surface, and points C and D are located at least on the lateral edge of the sole lower surface. Furthermore, the area from point C to point D on the lateral edge of the sole lower surface constitutes a flat lateral stability area, point C is located further on the medial edge of the sole lower surface, and the area from point C to point E on the medial edge of the sole lower surface constitutes a flat lateral stability area, and in the stable posture, the medial stability area and the lateral stability area are in contact with the ground.

[0012] According to the present invention, when the sole touches the ground, it touches the ground at two points, namely, point C, which corresponds to a position 0.45×L from the origin O, and point D, which corresponds to a position 0.60×L from the origin O. This prevents the sole from sinking toward the heel after touching the ground, and ensures a stable sole posture (stable posture), thereby preventing time loss and power loss.

[0013] In contrast, with a sole that touches the ground at a single point when the foot touches the ground, although it is possible to minimize heel drop, some degree of drop will occur, resulting in loss of time and power.

[0014] According to the present invention, the bottom surface of the sole of the heel and toe is separated from the ground (i.e., floating) in the stable posture, so that unintended contact of the heel with the ground can be prevented when the foot touches the ground. Furthermore, according to the present invention, the straight line connecting the center of the heel and the metatarsophalangeal joint in the stable posture forms an angle of 5 degrees or more with the ground, so that the heel can be placed above the forefoot in a heel-up state, which matches the forefoot posture.

[0015] Thus, according to the present invention, a stable sole posture (stable posture) can be taken while maintaining the forefoot posture when touching the ground, which allows the runner to easily feel a stable contact with the ground when running with a forefoot stance, and allows the runner to easily roll forward, allowing the runner to transition to the start of heel lift after touching the ground smoothly and efficiently. In this way, the phase from touching the ground to the start of heel lift can be fully supported, so that the forefoot stance can be more naturally promoted and more sustainable when running.

[0016] According to the present invention, when the intersection point E is the line that passes from the origin O along the sole upper surface and passes through the position of 0.70×L and intersects with the reference line S at right angles and the sole lower surface, in a stable posture, the sole lower surface comes into contact with the ground at three points, namely, points C and D, and point E forward of points C and D, so that a more stable sole posture can be taken and the forefoot posture can be further stabilized. In the present invention, point E is located on the medial side edge of the sole lower surface, and points C and D are located on at least the lateral side edge of the sole lower surface, so that when the sole comes into contact with the ground, the sole comes into contact with the ground at three points, namely, points C and D of the lateral side edge, and point E of the medial side edge (i.e., three points that form a triangle), so that a more stable sole posture can be taken and the forefoot posture can be further stabilized. Furthermore, in the present invention, the area on the underside of the sole extending from point C to point D on the lateral edge constitutes a flat lateral stability area, point C is located further on the medial edge of the underside of the sole, and the area on the underside of the sole extending from point C to point E on the medial edge of the sole constitutes a flat medial stability area, and since the medial stability area and the lateral stability area are in contact with the ground in a stable posture, the sole comes into contact with the ground over a wider contact area on the medial and lateral sides, allowing for an even more stable sole posture and making the forefoot posture even more stable.

[0017] In the present invention, in a stable posture, the underside of the sole is off the ground in a rearward region along the sole top surface from a position 0.25×L from the origin O, and in a forward region along the sole top surface from a position 0.80×L from the origin O.

[0025] In the present invention, a curved plate that extends continuously while curving is disposed inside the sole, and the curved plate extends at least from the center of the heel to the region of the metatarsophalangeal joint, which encourages the heel to lift when weight is transferred to the toes, thereby supporting propulsion during running. Effect of the Invention

[0026] As described above, according to the present invention, it is possible to fully support the phase from contact with the ground to the start of heel lift, so as to more naturally encourage a forefoot sprinting style while running and make it more sustainable. [Brief description of the drawings]

[0027] [Figure 1] 1 is a schematic side view of a shoe incorporating a sole according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic side view of the sole (FIG. 1). [Diagram 3] FIG. 2 is a schematic side view of the sole (FIG. 1). [Figure 4] FIG. 2 is a schematic bottom view of the sole (FIG. 1). [Diagram 5] FIG. 5 is a schematic view of the medial side of the sole (FIG. 4). [Figure 6] FIG. 5 is a schematic view of the outer instep side of the sole (FIG. 4). [Figure 7] FIG. 2 is a diagram for explaining the state of the shoe (FIG. 1) during running, and shows the movement of the shoe relative to the ground in chronological order from (a) to (d). [Figure 8] FIG. 1 is a diagram for explaining the state of conventional shoes when running, and shows the movement of the shoes relative to the ground in chronological order from (a) to (d). [Figure 9]FIG. 4 is a schematic side view of a sole according to a second embodiment of the present invention. [Figure 10] FIG. 10 is a schematic bottom view of the sole (FIG. 9). [Figure 11] FIG. 11 is a schematic side view of a sole according to a third embodiment of the present invention. [Figure 12] FIG. 12 is an overall perspective view of a curved plate provided on the sole (FIG. 11) as viewed from above on the front side. [Figure 13] FIG. 13 is an overall perspective view of the curved plate (FIG. 12) seen from above on the rear side. [Figure 14] FIG. 13 is a side view of the curved plate (FIG. 12). [Figure 15] FIG. 11 is a schematic side view of a sole according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. <First Example> Figures 1 to 8 are diagrams for explaining a sole according to a first embodiment of the present invention and a shoe equipped with the sole. In these diagrams, Figure 1 shows the appearance of the shoe, Figures 2-3 and 5-6 are schematic side views of the sole, Figure 4 is a schematic bottom view of the sole, Figure 7 is a diagram showing the state of the shoe in chronological order when running, and Figure 8 is a diagram showing the state of a conventional shoe in chronological order when running for comparison with Figure 7. Here, sports shoes, particularly running shoes for middle to long distances, are taken as an example of shoes.

[0029] In the following explanation (as well as in the second to fourth embodiments described later), the terms "upper" (top) and "lower" (bottom) refer to the vertical positional relationship of the shoe, the terms "front" (front side) and "rear" (rear side) refer to the front-to-rear positional relationship of the shoe, and the "width direction" refers to the left-to-right direction of the shoe. In other words, in the case of Fig. 1 as an example, the terms "upper" and "lower" refer to the top and bottom of the figure, respectively, the terms "front" and "rear" refer to the right and left of the figure, respectively, and the "width direction" refers to the direction perpendicular to the plane of the figure.

[0030] As shown in FIG. 1, the shoe SH is constructed by a sole 1 and an upper (upper part) U fixed to the upper side of the sole 1 by gluing, sewing, or the like. The sole 1 has a midsole 2 arranged on the upper side and an outsole 3 arranged on the lower side. The upper surface (sole upper surface) 20 of the sole 1 is formed by the surface 20 of the midsole 2 that contacts the sole of the foot, and the lower surface (sole lower surface) 31 of the sole 1 is formed by the ground contact surface 31 of the outsole 3. The outsole 3 is fixed to the lower surface 21 of the midsole 2 by gluing, or the like. The midsole 2 and the outsole 3 extend in the front-rear direction from the heel part of the sole 1 (the left end part in FIG. 1) to the toe part (the right end part in FIG. 1).

[0031] The midsole 2 is preferably made of a soft elastic material, specifically, a thermoplastic synthetic resin such as ethylene-vinyl acetate copolymer (EVA) or a foam thereof, a thermosetting resin such as polyurethane (PU) or a foam thereof, or a rubber material such as butadiene rubber or chloroprene rubber or a foam thereof. The outsole 3 is preferably made of a hard elastic material, specifically, a thermoplastic resin such as thermoplastic polyurethane (TPU) or polyamide elastomer (PAE), a thermosetting resin such as epoxy resin, or rubber. Note that the materials of the midsole 2 and the outsole 3 are not limited to these, and any other appropriate materials may be selected.

[0032] As shown in FIG. 1 and FIG. 2, a straight line connecting the position So of the rear end (rear end of the heel) of the sole upper surface 20 and the position Se of the tip of the toe is defined as a reference line S. Here, the sole upper surface 20 matches the shape of the bottom surface of the last (shoe mold) used when assembling the shoes SH. Next, the position So of the rear end is defined as the origin O, and the distance from the origin O to the position Se of the tip of the toe measured along the sole upper surface 20 is defined as L. The intersection point between the line passing through the position 20m of 0.45×L from the origin O along the sole upper surface 20 and perpendicular to the reference line S and the sole lower surface 31 is defined as C, and the intersection point between the line passing through the position 20n of 0.60×L from the origin O along the sole upper surface 20 and perpendicular to the reference line S and the sole lower surface 31 is defined as D. In the same figure, the intersection point between the line passing through the position 20m and perpendicular to the reference line S and the reference line S is indicated as Sp, and the intersection point between the line passing through the position 20n and perpendicular to the reference line S and the reference line S is indicated as Sq.

[0033] When the sole 1 is in a stable position in which it comes into contact with the ground R at points C and D, the sole lower surface 31 is separated from the ground R at the heel and toe (i.e., floating).

[0034] Here, point D on the sole underside 31, which is located below position 20n, 0.60×L from the origin O along the sole underside 20, corresponds to the position of the ball of the little toe of the shoe wearer's foot (i.e., near the base of the fifth toe (little toe)).

[0035] As shown in FIG. 2, when the angle (acute angle) that a line T that connects a heel center position 20h, which is located at 0.15×L from the origin O along the sole upper surface 20, and a metatarsophalangeal joint position 20j, which is located at 0.68×L from the origin O, makes with the ground R is θ, in the stable posture, θ≧5° is set to.

[0036] Preferably, as shown in FIG. 3, the sole lower surface 31 is separated from the ground in a rearward (leftward) region from a position 20s that is 0.25×L from the origin O along the sole upper surface 20. The position 20s roughly corresponds to the position of the ankle. More preferably, the sole lower surface 31 is separated from the ground in a rearward region from a position 0.27×L from the origin O (not shown) along the sole upper surface 20. This is to prevent the heel from touching the ground at the initial contact of the sole 1. Also, the sole lower surface 31 is separated from the ground in a frontward (rightward) region from a position 20t that is 0.80×L from the origin O along the sole upper surface 20. Alternatively, the sole lower surface 31 is separated from the ground in a frontward region from a position 0.81×L from the origin O along the sole upper surface 20. This is to facilitate forward rolling of the toe when the load is transferred to the toe.

[0037] As shown in FIG. 4, the heel H, midfoot M, and forefoot F of the sole 1 can be expressed using the distance L from the origin O to the tip of the toes Se measured along the sole upper surface 20 as follows: i) Heel: 0~0.25×L and rear edge of heel ii) Midfoot: 0.25×L~0.60×L iii) Forefoot: 0.60×L~1.00×L

[0038] In the example shown in Fig. 4, points C and D on the sole lower surface (i.e., the ground contact surface of the outsole 3) 31 are located at 0.45 x L and 0.60 x L from the origin O on the outer instep edge (including the position closer to the outer instep edge) and inner instep edge (including the position closer to the inner instep edge) of the outsole 31, respectively. In the example shown in Fig. 4, a recess 21a is formed on the lower surface of the midsole 2, which is located approximately in the center in the width direction, extends in the front-rear direction, and has a certain depth relative to the lower surface of the midsole 2. The outsole 3 is disposed in the area on the lower surface of the midsole 2 excluding the recess 21a, and has a notch 31a corresponding to the recess 21a.

[0039] As shown in Fig. 5 (a side view of the inner instep side of Fig. 4) and Fig. 6 (a side view of the outer instep side of Fig. 4), the midsole 2 of the sole 1 has a standing wall portion 22 rising upward from the sole upper surface (i.e., the surface that contacts the sole of the foot) 20, and the standing wall portion 22 is provided on the outer peripheral edge of the sole upper surface 20 and is disposed so as to surround the sole upper surface 20 along the outer peripheral edge of the sole upper surface 20. Figs. 1 to 3 show an example in which the standing wall portion 22 is omitted.

[0040] Preferably, as shown in the hatched area in Fig. 4 and in Fig. 5 and 6, the area on the sole lower surface 31 extending from a position of 0.45 x L to a position of 0.60 x L from the origin O is formed flat and forms a stable area. In a stable posture in which the sole 1 touches the ground R at points C and D, preferably, the entire hatched area (stable area) on the sole lower surface 31 touches the ground R.

[0041] Next, the effects of this embodiment will be described with reference to FIG. Fig. 7(a) shows the initial contact state of the sole 1. At this time, the sole 1 is in a sole posture in which it is in contact with the ground R at points C and D (Figs. 1 to 3) on the sole underside 31, for example, points C and D (Fig. 4) on the outer instep side of the sole underside 31, and maintains a stable posture.

[0042] As described above, in a stable posture in which the sole 1 contacts the ground R at two points, points C and D, the sole underside 31 is positioned away from (floating) the ground R at the heel and toe, and more preferably, the sole underside 31 is positioned away from (floating) the ground R in the rear region from a position 0.25×L (more preferably 0.27×L) from the origin O, and in the front region from a position 0.80×L (or 0.81×L) from the origin O.

[0043] This prevents unintended contact of the heel with the ground at the time of initial contact with the ground, naturally encouraging a forefoot running style and stabilizing the forefoot posture, while also allowing for smooth rolling onto the toes, encouraging a more natural forefoot running style.

[0044] In addition, in the stable posture, as described above, when the angle that the line connecting heel center position 20h, which is located 0.15×L from the origin O along sole upper surface 20 in Fig. 2, and metatarsophalangeal joint position 20j, which is located 0.68×L from the origin O, makes with the ground is θ, the inequality θ≧5° is satisfied. As a result, the heel part of sole 1 can be positioned above the forefoot part (i.e., in a heel-up state), matching the forefoot posture.

[0045] 7(b) shows the phase of the intermediate movement after the initial ground contact of the sole 1. At this time, as shown in the figure, the load acts on the sole 1, so that the sole 1 is gradually compressed in the vertical direction, but in this case, not only points C and D on the outer instep side of the sole underside 31 but also points C and D on the inner instep side of the sole underside 31 are in contact with the ground R, so that the stable posture of the sole 1 is maintained and the forefoot posture is maintained.

[0046] In this way, not only can the sole lower surface 31 provide a natural support effect, but it is also possible to eliminate the heel collapse after the initial contact with the ground. As a result, the load on the runner caused by the heel collapse (i.e., the strain on the muscles caused by lifting the heel after the heel collapse) can be reduced, improving running efficiency.

[0047] 7(c) shows the state where the maximum load acts on the sole 1 after the initial contact with the ground. At this time, as shown in the figure, the amount of compressive deformation of the sole 1 is at its maximum, but even in this case, the ground contact state is maintained at points C and D on the outer instep side of the sole lower surface 31 and points C and D on the inner instep side of the sole lower surface 31, so the sole 1 maintains a stable posture and maintains a forefoot posture.

[0048] Next, Fig. 7(d) shows the state after the heel starts to lift. At this time, as shown in the figure, the contact area of ​​the sole lower surface 31 with the ground R has moved toward the toe side. 7In the (c) situation, a stable forefoot position is maintained by contacting the ground at points C and D. 7 The transition to (d) can be done smoothly, allowing the runner to start the lift without any waste or strain while running.

[0049] For comparison, FIG. 8 shows the state of a conventional shoe during running. In this figure, as in FIG. 7, the movement of the shoe against the ground is shown in chronological order from (a) to (d). Each phase (a) to (d) in FIG. 8 corresponds to each phase (a) to (d) in FIG. 7, respectively. Also, in FIG. 8, the same reference numerals as in FIG. 7 indicate the same or corresponding parts.

[0050] 8(a) shows the state of the sole 1' at the initial contact with the ground. For comparison with this embodiment, the figure shows a state in which the sole lower surface 31' contacts the ground R at point C' in the midfoot or forefoot.

[0051] When the sole 1' touches the ground at point C' as shown in Figure 8(a), it can roll either forward or backward. If it rolls backward, the forefoot posture is greatly disrupted, making it difficult to maintain the forefoot running style. Therefore, the runner's skill is required to roll forward from the point C' contact state.

[0052] 8(b) shows a phase of an intermediate movement after the initial contact of the sole 1' with the ground. At this time, as shown in the figure, the heel part of the sole 1' drops (i.e., descends) toward the ground R by a drop (descent) amount d.

[0053] Next, Fig. 8(c) shows the initial contact with the sole 1. ’1 shows the heel lifting phase after the maximum load acts on the heel. In this case, the heel drop (descent) d is large in the phase of FIG. 1(b), so the heel lift amount u is large, and therefore it is not possible to quickly transition from the phase of FIG. 1(b) to the phase of FIG. 1(c) where the heel is lifted. As a result, it is not possible to smoothly transfer from the heel to the forefoot after landing, and it is not possible to achieve a smooth shift of the center of gravity from the heel to the toe. In addition, the large heel d d places a large load on the runner, making it difficult to improve running efficiency.

[0054] Fig. 8(d) shows the state after the heel starts to lift, and at this time, the contact area of ​​the sole lower surface 31' with the ground R moves toward the toe. In this case, the heel has dropped a large amount by the time the state shown in the figure is reached, placing a large burden on the runner, and it is therefore not possible to efficiently and comfortably lead the runner to start lifting while running.

[0055] <Second Example> Figures 9 and 10 are diagrams for explaining a sole according to a second embodiment of the present invention. In these figures, Figure 9 is a schematic side view of the sole, and Figure 10 is a schematic bottom view of the sole, which correspond to Figures 3 and 4 of the first embodiment, respectively. In each figure, the same reference numerals as those in the first embodiment indicate the same or corresponding parts.

[0056] 9, the intersection point E between a line passing through a position 20r of 0.70×L from the origin O along the sole upper surface 20 and perpendicular to the reference line S and the sole lower surface 31 is denoted as E. In the figure, the intersection point between the line passing through the position 20r and perpendicular to the reference line S and the reference line S is indicated as Sr.

[0057] In a stable position where the sole lower surface 31 is in contact with the ground R at points C and D, the sole lower surface 31 also is in contact with the ground R at point E. In this stable position, similarly to the first embodiment, the sole lower surface 31 at the heel and toe is separated from the ground R (i.e., floating).

[0058] Here, point E on the sole underside 31, which is located below position 20r, 0.70×L from the origin O along the sole underside 20, corresponds to the position of the ball of the shoe wearer's foot (i.e., the bulging part at the base of the first toe (big toe)).

[0059] Similarly to the first embodiment, when a straight line connecting the heel center position (not shown) located at 0.15×L from the origin O along the sole upper surface 20 and the metatarsophalangeal joint position (not shown) located at 0.68×L from the origin O forms an angle (acute angle) θ with the ground R, in the stable posture, θ≧5° is set to.

[0060] Furthermore, similarly to the first embodiment, the sole underside 31 is preferably separated from the ground in a region rearward (leftward in the figure) of a position 20s along the sole upper surface 20 that is 0.25×L from the origin O, and in a region forward (rightward in the figure) of a position 20t along the sole upper surface 20 that is 0.80×L from the origin O.

[0061] Also, as shown in FIG. 10, point C on the sole underside (the contact surface of the outsole 31) 31 is located at a position 0.45×L from the origin O, on the lateral edge (including the position closer to the lateral edge) and medial edge (including the position closer to the medial edge) of the sole underside 31, point D is located at a position 0.60×L from the origin O, on the lateral edge (including the position closer to the lateral edge) of the sole underside 31, and point E is located at a position 0.70×L from the origin O, on the medial edge (including the position closer to the medial edge) of the sole underside 31.

[0062] 10, the area (including points C and D) on the lateral side of the sole lower surface 31 extending from 0.45×L to 0.60×L from the origin O is preferably flat and forms a lateral stable area. In a stable posture in which the sole 1 is in contact with the ground R at points C and D, the entire lateral stable area (slanted area) on the lateral side of the sole lower surface 31 is preferably in contact with the ground R.

[0063] 10, the area extending from 0.45×L to 0.70×L from the origin O on the medial side of the sole lower surface 31 (area including points C and E) is formed flat and constitutes a medial side stable area. In a sole posture in which the sole 1 touches the ground R at points C and E, preferably, the entire medial side shaded area (medial side stable area) of the sole lower surface 31 touches the ground R.

[0064] In this second embodiment, as in the first embodiment, during the initial contact phase of the sole 1, a stable posture is maintained in which the sole underside 31 touches the ground R at points C and D (Figure 10) on the outer instep side, and the sole underside 31 is positioned away from the ground R (floating) at the heel and toe, more preferably in the rear region from a position 0.25×L from the origin O and in the forward region from a position 0.80×L from the origin O. Therefore, during initial contact, unintended contact of the heel with the ground is prevented, promoting a natural forefoot gait and stabilizing the forefoot posture, while also allowing smooth rolling onto the toes, promoting a more natural forefoot gait.

[0065] Furthermore, in the stable posture, as in the first embodiment, when the angle that a straight line connecting the heel center position, which is located 0.15×L from the origin O along the sole upper surface 20, and the metatarsophalangeal joint position, which is located 0.68×L from the origin O, makes with the ground is θ, the inequality θ≧5° is satisfied, so that the heel portion of the sole 1 can be positioned upward with respect to the forefoot portion (i.e., in a heel-up state) to conform to the forefoot posture.

[0066] Next, in the intermediate movement phase after the initial contact of the sole 1 with the ground and in the phase when the maximum load is applied, as in the first embodiment, the load acts on the sole 1, compressing the sole 1 in the vertical direction. In this case, not only the contact state at points C and D on the outer instep side of the sole underside 31, but also the contact state at points C and E on the inner instep side of the sole underside 31 are maintained, so that the sole 1 maintains a stable posture and maintains a forefoot posture.

[0067] This not only provides a natural support effect from the sole underside 31, but also makes it possible to eliminate the heel from collapsing after the initial contact with the ground. As a result, the load on the runner caused by the heel collapsing (i.e., the strain on the muscles caused by lifting the heel after it has collapsed) can be reduced, improving running efficiency.

[0068] Next, when the heel starts to lift, a stable forefoot position is maintained as in the first embodiment, so the heel can be smoothly lifted. This allows the runner to start lifting efficiently and without strain while running.

[0069] <Third Example> Figures 11 to 14 are diagrams for explaining a sole according to a third embodiment of the present invention. In these figures, Figure 11 is a schematic side view of the sole, and Figures 12 to 14 are external views of a curved plate provided on the sole. In these figures, the same reference numerals as those in the first and second embodiments indicate the same or corresponding parts.

[0070] As shown in FIG. 11, in this third embodiment, as in the first and second embodiments, when the sole 1 is in a stable position with the sole 1 in contact with the ground R at points C and D, the sole underside 31 is separated from the ground (floating) at the heel and toe, preferably in the region along the sole upper surface 20 rearward (leftward in the figure) from a position 0.25×L (not shown) from the origin O, and in the region along the sole upper surface 20 forward (rightward in the figure) from a position 0.80×L (not shown) from the origin O.

[0071] Similarly to the first and second embodiments, when a straight line connecting the heel center position 20h, which is located at 0.15×L from the origin O along the sole upper surface 20, and the metatarsophalangeal joint position (not shown), which is located at 0.68×L from the origin O, forms an angle (acute angle) θ with the ground R, in a stable posture, θ≧5° is set to.

[0072] This third embodiment differs from the first and second embodiments in that a curved plate P is provided inside the midsole 2 of the sole 1, as shown in Fig. 11. The curved plate P is a member that extends continuously in the front-rear direction while being curved up and down (see Figs. 12 to 14). Here, for convenience of illustration, the curved plate P is shown by a thick line. Also, in this example, the side surface of the curved plate P is shown on the side surface of the midsole 2, but, unlike this, the curved plate P may be built into the midsole 2 so that the side surface of the curved plate P does not appear on the side surface of the midsole 2.

[0073] As shown in Fig. 11, the curved plate P starts at the heel center position 20h, which is located 0.15 x L from the origin O, and extends in the front-rear direction while curving to a region that terminates at a position 0.90 x L from the origin O (near the toes). That is, the curved plate P extends gently diagonally downward from the position 20h while curving substantially linearly or slightly upwardly convexly toward the front, changes to a downwardly convex shape at or near the position 20m, and extends toward the end while curving substantially linearly or slightly downwardly convexly toward the front. The curved plate P has elasticity in the up-down direction.

[0074] The curved plate P is a thin sheet-like member having a thickness of, for example, about 1 to 2 mm. The curved plate P is attached to the inside of the midsole 2 by, for example, insert molding. When the midsole 2 is composed of two layers, an upper and a lower midsole, the curved plate P may be bonded to the interface between the midsole layers.

[0075] The curved plate P is made of, for example, a thermoplastic resin such as thermoplastic polyurethane (TPU), polyamide elastomer (PAE), ABS resin, etc., which are relatively elastic materials, or a thermosetting resin such as epoxy resin, unsaturated polyester resin, etc. Also, the material of the curved plate P may be fiber reinforced plastic (FRP) using, for example, carbon fiber, aramid fiber, glass fiber, etc. as reinforcing fibers and a thermosetting resin or thermoplastic resin as a matrix resin.

[0076] As shown in Figs. 12 and 13, the curved plate P may have, at approximately the center in the width direction and the center in the front-rear direction, raised portions (or ribs) Pb that rise upward like a mountain and extend in the front-rear direction.

[0077] In this third embodiment, as in the first embodiment, during the initial contact phase of the sole 1, a stable posture can be maintained with the sole 1 in contact with the ground R at points C and D, stabilizing the forefoot posture and naturally encouraging a forefoot running style. Additionally, during the intermediate movement phase after initial contact and the phase when maximum load is applied, not only can the underside of the sole 31 provide a natural support effect, but it is also possible to eliminate sagging of the heel after initial contact.

[0078] In this case, since a curved plate P is provided inside the midsole 2, the load on the heel portion of the sole 1 can be reliably supported, and since the curved plate P is provided with a raised portion Pb, the rigidity of the curved plate P is increased, so that the load on the heel portion can be supported even more reliably.

[0079] Next, as in the first embodiment, when the heel begins to lift, a stable forefoot posture is maintained, so that the transition to the lift phase is smooth, allowing the runner to begin to lift efficiently and without strain while running.

[0080] In this case, when the load is shifted to the forefoot side, the runner steps on the forefoot side of the curved plate P, causing the rear end side of the curved plate P to rise upward due to a seesaw effect, thereby restricting the descent of the heel. In this way, a smooth shift of the center of gravity toward the toes can be achieved. Also, in this case, since the curved plate P extends to the area near the toes, when the toes push off, the elastic repulsive force of the curved plate P allows the runner to powerfully kick the ground R and obtain propulsion.

[0081] <Fourth Example> 15 is a schematic side view of a sole for explaining a sole according to a fourth embodiment of the present invention, in which the same reference numerals as those in the first to third embodiments denote the same or corresponding parts.

[0082] In this fourth embodiment, a curved plate P is provided inside the midsole 2 as in the third embodiment, but the length of the curved plate P is shorter than that of the third embodiment, and the position of the starting end of the curved plate P is the same as in the third embodiment, but the position of the end is 0.68×L from the origin O (the metatarsophalangeal joint position). That is, in this case, the curved plate P extends from the center of the heel to the metatarsophalangeal joint position.

[0083] The fourth embodiment is similar to the third embodiment except that the curved plate P does not extend to the toe portion, and provides substantially the same effects as the third embodiment.

[0084] <First Modification> In the first embodiment, point C corresponding to a position 0.45×L from the origin O and point D corresponding to a position 0.60×L from the origin O are both located on the outer shell side edge (including a position closer to the outer shell side edge (same below)) and the inner shell side edge (including a position closer to the inner shell side edge (same below)), but the application of the present invention is not limited to this.

[0085] Point C and point D may be arranged slightly inward in the width direction from the medial side edge and the lateral side edge (i.e., toward the center in the width direction). Alternatively, either point C or point D may be arranged at the medial side edge and the lateral side edge, and either point C or point D may be arranged slightly inward in the width direction from the medial side edge and the lateral side edge.

[0086] Similarly, in the second embodiment, point C is located on the medial side edge and the lateral side edge, point D is located on the lateral side edge, and point E, which corresponds to a position of 0.70×L from the origin O, is located on the medial side edge, but the application of the present invention is not limited to this.

[0087] Point C may be located slightly inward in the width direction from the medial and lateral edges, point D may be located slightly inward in the width direction from the lateral edges, and point E may be located slightly inward in the width direction from the medial edge. Alternatively, any one or two of points C, D, and E may be located on the medial and lateral edges, and the remaining one or two of points C, D, and E may be located slightly inward in the width direction from the medial and lateral edges.

[0088] <Second Modification> In the first embodiment, an example is shown in which the foot touches the ground at points C and D on the outer instep during the initial contact, and then touches the ground at four points, namely points C and D on the outer instep and points C and D on the inner instep, during the intermediate movement phase after the initial contact. However, the foot may also touch the ground at three points, namely points C and D on the outer instep and point D on the inner instep (i.e., three points that form a triangle), during the intermediate movement phase.

[0089] Similarly, in the second embodiment, an example is shown in which the foot is grounded at points C and D on the outer instep during initial contact, and then at four points, namely points C and D on the outer instep and points C and E on the inner instep during the intermediate movement phase after initial contact; however, the foot may be grounded at three points, namely points C and D on the outer instep and point E on the inner instep (i.e., three points that form a triangle), during the intermediate movement phase.

[0090] <Third modified example> In the first and second embodiments, an example was shown in which a recess 21a was formed on the underside of the midsole 2 and a notch 31a corresponding to the recess 21a was formed in the outsole 3, but these recesses 21a and notches 31a may be omitted.

[0091] <Other Modifications> The above-described embodiment and each modification should be considered in all respects as merely illustrative of the present invention, and not restrictive. Those skilled in the art to which the present invention pertains may, when considering the teachings above, construct various modifications and other embodiments that incorporate the principles of the present invention without departing from the spirit and essential characteristics of the present invention, even if not expressly described herein. [Industrial Applicability]

[0092] As described above, the present invention is useful for a shoe sole that can more naturally encourage a forefoot sprint while running and fully support the phase from contact with the ground to the start of heel lift in a more sustainable manner. [Explanation of symbols]

[0093] 1: Sole 2: Midsole 20: Surface that comes into contact with the sole of the foot (top of sole) 20h: Heel center position 20j: Metatarsophalangeal joint position 3: Outsole 31: Ground surface (underside of sole) S: Reference line So: The rearmost position Se: Toe tip position L: Journey C, D, E: Intersection P: Curved plate SH: Sports shoes (shoes) R: Ground [Prior art documents] [Patent documents]

[0094] [Patent Document 1] JP 2020-163084 A (see paragraphs

[0020] to

[0024] ,

[0028] to

[0030] , and FIG. 9)

Claims

1. A sole of a shoe, The shoe extends from the heel to the toe, has a sole upper surface and a sole lower surface, When a straight line connecting the rearmost end position of the sole upper surface and the position of the tip of the toe is defined as a reference line S, the position of the rearmost end is defined as an origin O, a distance measured from the origin O to the position of the tip of the toe along the sole upper surface is defined as L, a point of intersection between a line passing from the origin O along the sole upper surface to a position of 0.45×L and perpendicular to the reference line S and the sole lower surface is defined as C, and a point of intersection between a line passing from the origin O along the sole upper surface to a position of 0.60×L and perpendicular to the reference line S and the sole lower surface is defined as D, and a sole posture in which the sole touches the ground at points C and D is defined as a stable posture, In the stable posture, the bottom surface of the sole at the heel portion and the toe portion is separated from the ground, When an angle formed by a straight line connecting a heel center position, which is located at 0.15×L from the origin O along the upper surface of the sole, and a metatarsophalangeal joint position, which is located at 0.68×L from the origin O, and the ground is θ, in the stable posture, θ≧5° is set to When a line that passes from the origin O along the sole upper surface and passes through a position of 0.70×L and is perpendicular to the reference line S and an intersection point E is defined as a point E between the sole lower surface and the line, in the stable posture, the sole lower surface is in contact with the ground at points C, D, and E, Point E is located on the medial side edge of the sole lower surface, and points C and D are located on at least the lateral side edge of the sole lower surface; The area on the underside of the sole extending from point C to point D of the outer instep edge constitutes a flat outer instep stability area, point C is located on the inner instep edge of the underside of the sole, and the area on the underside of the sole extending from point C to point E of the inner instep edge constitutes a flat inner instep stability area, and in the stable posture, the inner instep stability area and the outer instep stability area are in contact with the ground. A shoe sole characterized by:

2. In claim 1, In the stable posture, the sole lower surface is separated from the ground in a rear region from a position of 0.25×L from the origin O along the sole upper surface and in a front region from a position of 0.80×L from the origin O along the sole upper surface. A shoe sole characterized by:

3. In claim 1, A curved plate is disposed inside the sole and extends continuously while being curved, and the curved plate extends at least from the center position of the heel to the region of the metatarsophalangeal joint position. A shoe sole characterized by:

Images