Boot sole

Abstract

To provide a shoe sole that is lightweight, comfortable to wear, and provides stable walking even when used for town use or walking, while preventing the sole from feeling any pressure on the foot when landing when running or jogging, suppressing pronation and enabling quick weight transfer, and also being widely usable for sports requiring weight transfer such as golf, tennis, basketball, soccer and skateboarding. [Solution] The present invention relates to a sole having at least a sole body made of a flexible material and a plate made of a material having a higher flexural modulus than the flexible material constituting the sole body, wherein at least two of the plates are included in the sole body and two of the plates satisfy all of the following conditions 1 to 3. Condition 1: In a bottom perspective view of the sole, one of the two plates is positioned on the medial side and the other plate is positioned on the lateral side of the last center line (called the "PCL"). Condition 2: The long axes of both plates form an angle between 0° and 30° with respect to the PCL. Condition 3: When the tip of the toe side of the sole is set to 1 and the tip of the heel side is set to 0, the entirety of both plates must be within the range of 0.2 to 0.7.

Description

[Technical field]

[0001] The present disclosure relates to shoe soles. [Background technology]

[0002] In recent years, the global spread of coronavirus infection has led to prolonged lockdowns and self-restraint lifestyles, particularly in urban areas, and casual exercise to maintain health has been attracting attention. In particular, more and more people are starting to run, which can be done alone anywhere, and many of them are so-called fun runners, runners who enjoy running for the purpose of maintaining and improving their health. Shoes are an essential sports equipment for them to enjoy running, and they choose from commercially available shoes to wear. Each manufacturer is designing shoes with various ingenuity, such as sole shape, midsole cushioning, and plates, including for advanced runners such as serious runners and athletes.

[0003] In particular, in recent years, thick-soled rocker shoes have been a trend in the shoe industry. The sole is thickened to absorb the impact from the ground, and a rocker shape like a cradle or rocking chair has been proposed to make it easier to move forward. However, because the sole is soft, it does not have the effect of suppressing excessive pronation (the natural movement of the human body in which the sole rotates inward to disperse the impact when touching the ground), which is considered to be one of the causes of running injuries, and because the contact area with the ground is small, the foot is unstable when used in daily life other than exercise, such as for town use.

[0004] A technology has been disclosed in which an elastic material such as a carbon plate is inserted into such a soft sole, causing the sole to function as a spring in the length direction (vertical direction) of the foot, providing forward propulsion.

[0005] For example, as shown in Patent Document 1, a shoe is disclosed in which a flexible elastic member (such as carbon fiber reinforced plastic) extending from the forefoot to the heel is mounted on the midsole. The elastic member is arranged so as to bend together with the bottom of the shoe with each step taken while walking or running in the region of the wearer's forefoot and the bulge at the base of the toes (MTP joint), and stores and releases energy in response to the bending. So-called full carbon shoes, which use carbon fiber reinforced plastic as the elastic member, have very high resilience and have become the standard positioning of top shoes at leading companies for advanced runners who have mastered the forefoot running style (a running style in which the foot lands on the forefoot) and can continue running with a stable form by transferring weight well to the forefoot. However, many beginner runners do not have a stable form from the beginning, and full carbon is hard, so that for fun runners who also run or walk at a relatively slow pace, the function of the shoe cannot be fully utilized, and the comfort of wearing it feels hard, making it unsuitable.

[0006] Shoes with partial plates in the midfoot and heel are also known. Patent Document 2 discloses a shoe with carbon fiber reinforced plastic placed as a spring in the center of the midfoot. Compared to a pull plate, a small, elongated plate has a small area, and CFRP (carbon fiber reinforced plastic) is placed in the small area to efficiently store and release energy, but the impact on running is relatively small compared to a full plate. In addition, it cannot be expected to suppress excessive pronation of the foot, especially when landing on the heel.

[0007] Patent Document 3 proposes a lightweight shoe that suppresses excessive pronation by arranging a wavy plate in the heel and achieving both cushioning and stability when the heel strikes the ground, thereby enabling smooth load (body weight) transfer to the forefoot when the heel strikes the ground. Patent Document 4 discloses a shoe that extends the medial and lateral shank parts of the arch part from the front end of the plate to the forefoot, supporting the arch of the foot and preventing (excessive) twisting with the arch part and collapse of the arch part. Furthermore, Patent Document 5 discloses a technology for suppressing pronation by providing a pair of carbon fiber reinforced plastic pieces from the heel part to the midfoot part. In this way, installing a plate in the heel area provides stabilization when the heel strikes the ground, making it easy for beginners who do not have fully developed calf muscles or Achilles tendons, or who are recommended to use a heel-strike running technique (landing on the heel) to prevent running injuries, to adopt this style. However, because the plate is hard, some people feel a pressure on the soles of their feet when landing, and there was room for improvement in terms of comfort. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent No. 5,052,130 [Patent Document 2] U.S. Patent Application Publication No. 2019-0150563 [Patent Document 3] Patent No. 4399431 specification [Patent Document 4] Patent No. 3403952 specification [Patent Document 5] US Patent Application Publication No. 2016-0316852 Summary of the Invention [Problem to be solved by the invention]

[0009] Therefore, it would be useful to provide a sole that is lightweight, comfortable to wear, and provides stable walking when walking around town, while preventing pressure on the soles of the feet when landing while running or jogging, suppressing pronation and enabling quick weight transfer, and can also be used in a wide range of sports that require weight transfer, such as golf, tennis, basketball, soccer, and skateboarding. [Means for solving the problem]

[0010] Therefore, we provide a sole having at least a sole body made of a flexible material and a plate made of a material having a higher flexural modulus than the flexible material constituting the sole body, wherein at least two of the plates are included in the sole body and two of the plates satisfy all of the following conditions 1 to 3.

[0011] Condition 1: In a bottom perspective view of the sole, one of the two plates is positioned on the medial side and the other plate is positioned on the lateral side of the last center line (hereinafter referred to as "PCL").

[0012] Condition 2: The long axes of both plates form an angle between 0° and 30° with respect to the PCL.

[0013] Condition 3: When the tip of the toe side of the sole is set to 1 and the tip of the heel side is set to 0, the entirety of both plates must be within the range of 0.2 to 0.7. Effect of the Invention

[0014] The shoe sole of the present invention reduces the feeling of pressure on the sole of the foot when landing while running or jogging, suppresses pronation and enables quick weight transfer, while also providing a lightweight, comfortable fit and stable walking when used around town or walking. [Brief description of the drawings]

[0015] [Figure 1] FIG. 13 is a diagram for explaining the relationship between the PCL and the angle of the long axis of the plate in a bottom perspective view of the shoe sole. [Diagram 2] FIG. 2 is a bottom perspective view showing an example of a shoe sole according to the present invention. [Diagram 3] FIG. 4 is a bottom perspective view showing another example of a shoe sole according to the present invention. [Figure 4] FIG. 4 is a bottom perspective view showing another example of a shoe sole according to the present invention. [Diagram 5] FIG. 4 is a bottom perspective view showing another example of a shoe sole according to the present invention. [Figure 6] FIG. 4 is a bottom perspective view showing another example of a shoe sole according to the present invention. [Figure 7] FIG. 4 is a bottom perspective view showing another example of a shoe sole according to the present invention. [Figure 8] FIG. 4 is a bottom perspective view showing a comparative example of a shoe sole according to the present invention. [Figure 9] FIG. 4 is a bottom perspective view showing another example of a shoe sole according to the present invention. [Figure 10] FIG. 4 is a bottom perspective view showing another example of a shoe sole according to the present invention. [Figure 11] FIG. 4 is a bottom perspective view showing another example of a shoe sole according to the present invention. [Figure 12] FIG. 4 is a bottom perspective view showing another example of a shoe sole according to the present invention. [Figure 13] FIG. 4 is a bottom perspective view showing another example of a shoe sole according to the present invention. [Figure 14] FIG. 4 is a bottom perspective view showing another example of a shoe sole according to the present invention. [Figure 15] FIG. 4 is a bottom perspective view showing another example of a shoe sole according to the present invention. [Figure 16] FIG. 3 is a cross-sectional view of the sole of the shoe taken along line A-A' of FIG. 2. [Figure 17] FIG. 4 is a cross-sectional view of another example of a shoe sole according to the present invention. [Figure 18] FIG. 4 is a cross-sectional view of another example of a shoe sole according to the present invention. [Figure 19] FIG. 2 is an exploded view illustrating the structure of a shoe using the sole according to the present invention. [Figure 20] FIG. 3 is a side perspective view of the sole of FIG. 2 as seen from the outer instep side. [Figure 21]FIG. 2 is a side perspective view of the sole seen from the outer instep side, illustrating the state in which a plate having a bulging shape relative to the ground is placed. [Figure 22] FIG. 2 is a side perspective view of the sole as viewed from the outer instep side, illustrating the arrangement of the plate in the sole height direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The sole body used in the present invention is made of a flexible material. The flexible material is, for example, a material that can bend and restore when subjected to a force applied during walking at -50°C and 50°C. It is also preferable to use a soft elastic member with good cushioning properties. Specifically, examples of the material include a foam of a thermoplastic synthetic resin such as ethylene-vinyl acetate copolymer (EVA), a foam of a thermosetting resin such as polyurethane (PU), or a foam of a rubber material such as butadiene rubber or chloroprene rubber. In the present invention, it is preferable to use one having a JIS C hardness of 43° to 50°. If the JIS C hardness is less than 43°, the midsole body becomes too soft, and the foot sinks in greatly. In addition, the heel may be too deformed and pronation may not be sufficiently suppressed. On the other hand, if the JIS C hardness of the midsole body exceeds 50°, sufficient cushioning properties may be lost.

[0017] The sole body may be formed by laminating a plurality of members, and in this case, the plurality of members are preferably formed of different flexible materials. For example, it is a preferred embodiment to use rubber as the outsole, layered on the midsole made of the material having a JIS C hardness of 43° to 50°. When rubber is used as the outsole, it is expected that the durability of walking performance will be improved. The outsole may be made of translucent rubber. By using translucent rubber, the plate described later can be visually recognized from the outside, thereby improving the design of the sole. On the other hand, the outsole may be partially or entirely made of black rubber containing carbon black as a reinforcing filler.

[0018] The sole of the present invention has a plate made of a material having a flexural modulus higher than that of the flexible material constituting the sole body.

[0019] The material for the plate is not particularly limited as long as it has a higher flexural modulus than the flexible material for the sole body, but it is preferable to use fiber-reinforced plastic, which can provide a plate that is lightweight and has appropriate rigidity. The reinforcing fibers used in the fiber-reinforced plastic are not particularly limited, but glass fiber, aramid fiber, polyethylene fiber, silicon carbide fiber, and carbon fiber are preferably used. Glass fiber and carbon fiber are particularly preferred because they are lightweight, have high performance, and provide fiber-reinforced composite materials with excellent mechanical properties.

[0020] Further, the plate may be made of glass fiber alone or carbon fiber alone, or, taking into account the balance between performance and cost, both glass fiber and carbon fiber may be used in one plate.

[0021] Here, the glass fiber is not particularly limited, but E glass fiber, S glass fiber, C glass fiber, and D glass fiber are preferably used. From the viewpoint of the balance between cost and strength, E glass fiber is preferably used, S glass fiber is preferably used when high strength is required, C glass fiber is preferably used when acid resistance is required, and D glass fiber is preferably used when low dielectric constant is required. There is no particular limit to the average fiber diameter of the glass fiber, but the average fiber diameter of the glass fiber is preferably 4 to 20 μm, and more preferably the average fiber diameter is 5 to 16 μm. There is no particular limit to the lower limit, and usually, if it is 4 μm or more, sufficient effect can be obtained. If the average fiber diameter exceeds 20 μm, the strength tends to decrease.

[0022] The glass fiber basis weight is preferably 20 to 400 g / m 2 and more preferably 40 to 300 g / m 2 The weight of the glass fiber is 20g / m 2 In the above cases, the weaving properties of the glass fiber fabric are good, and the weight of the glass fiber is 400 g / m2 In the following cases, the resin easily reaches the center in the thickness direction during impregnation with an epoxy resin composition or the like, resulting in a glass fiber reinforced composite material in which unimpregnated portions (voids) are unlikely to remain, resulting in excellent mechanical properties such as compressive strength. In addition, it is preferable to use glass fibers after pretreating them with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, or an epoxy compound, in order to obtain better mechanical strength.

[0023] Next, the carbon fiber is not particularly limited, but polyacrylonitrile carbon fiber, rayon carbon fiber, pitch carbon fiber, etc. are preferably used. Among them, polyacrylonitrile carbon fiber with high tensile strength is particularly preferably used. As the form of carbon fiber, twisted yarn, untwisted yarn, non-twisted yarn, etc. can be used.

[0024] The carbon fiber preferably has a tensile modulus in the range of 180 to 600 GPa. If the tensile modulus is in this range, the fiber-reinforced composite material obtained can have rigidity, and the molded product obtained can be made lighter. Generally, the strength of carbon fiber tends to decrease as the modulus increases, but if the modulus is in this range, the strength of the carbon fiber itself can be maintained. A more preferred modulus is in the range of 200 to 440 GPa, and even more preferably in the range of 220 to 300 GPa. The range may be any combination of the upper and lower limits described above. Here, the tensile modulus of carbon fiber is a value measured according to JIS R7601-2006.

[0025] Commercially available carbon fibers include "TORAYCA (registered trademark)" T300 (tensile strength: 3.5 GPa, tensile modulus: 230 GPa), "TORAYCA (registered trademark)" T300B (tensile strength: 3.5 GPa, tensile modulus: 230 GPa), "TORAYCA (registered trademark)" T400HB (tensile strength: 4.4 GPa, tensile modulus: 250 GPa), "TORAYCA (registered trademark)" T700SC (tensile strength: 4.9 GPa, tensile modulus: 2 30 GPa), "TORAYCA (registered trademark)" T800HB (tensile strength: 5.5 GPa, tensile modulus: 294 GPa), "TORAYCA (registered trademark)" T800SC (tensile strength: 5.9 GPa, tensile modulus: 294 GPa), "TORAYCA (registered trademark)" T830HB (tensile strength: 5.3 GPa, tensile modulus: 294 GPa), "TORAYCA (registered trademark)" T1000GB- (tensile strength: 6.4 GPa, tensile modulus: 294 TORAYCA (registered trademark) T1100GC (tensile strength: 7.0 GPa, tensile modulus: 324 GPa), TORAYCA (registered trademark) M35JB (tensile strength: 4.7 GPa, tensile modulus: 343 GPa), TORAYCA (registered trademark) M40JB (tensile strength: 4.4 GPa, tensile modulus: 377 GPa), TORAYCA (registered trademark) M46JB (tensile strength: 4.2 GPa, tensile modulus: 436 GPa), Examples include "TORAYCA (registered trademark)" M55J (tensile strength: 4.0 GPa, tensile modulus: 540 GPa), "TORAYCA (registered trademark)" M60JB (tensile strength: 3.8 GPa, tensile modulus: 588 GPa), "TORAYCA (registered trademark)" M30SC (tensile strength: 5.5 GPa, tensile modulus: 294 GPa) (all manufactured by Toray Industries, Inc.), and PX35 (tensile strength: 4.1 GPa, tensile modulus: 242 GPa) (all manufactured by ZOLTEK Corporation).

[0026] The number of filaments in the carbon fiber is not particularly limited, but when a woven fabric described below is used for the plate, from the viewpoints of weaving productivity, the required tensile and flexural modulus and strength of the plate, and the design of the plate, the carbon fiber bundle is preferably composed of 1,000 to 70,000 filaments, and more preferably 1,000 to 60,000 filaments.

[0027] Next, the form of the reinforcing fibers used in the plate is not particularly limited, but it is preferable to adopt a unidirectional fiber-reinforced plastic in which the above-mentioned reinforcing fibers are aligned in one direction and combined with a matrix resin described below, or a woven fabric-reinforced plastic in which the above-mentioned reinforcing fibers are processed into a fabric and then combined with a matrix resin described below.

[0028] Here, the above-mentioned woven fabric will be described. The weaving structure of the woven fabric is not particularly limited, but plain weave, twill weave, satin weave, rib weave, sash weave, honeycomb weave, hack weave, imitation weave, and mat weave are preferably used. In the twill weave, 3-ply twill, 4-ply twill, 5-ply twill, 6-ply twill, stretched twill, curved twill, torn twill, jumping twill, chevron twill, mesh twill, overlapping twill, twisted twill, day and night twill, decorative twill, and gradation twill can be exemplified, and can be selected according to the design required for the plate. In addition, in the satin weave, 5-ply twill, 7-ply twill, 8-ply twill, 10-ply twill, irregular twill, spread twill, overlapping twill, mikage weave, day and night twill, and gradation twill can be exemplified, and can be selected according to the design required for the plate. In addition, examples of rib weave include warp rib weave, horizontal rib weave, and variable rib weave, and can be selected according to the design required for the plate. In addition, examples of chevron weave include regular chevron weave, variable chevron weave, irregular chevron weave, variable chevron weave, and opposite chevron weave, and can be selected according to the design required for the plate. Furthermore, the reinforcing fibers constituting the woven fabric may be the glass fiber alone or the carbon fiber alone, as exemplified above, or different types of glass fiber or carbon fiber may be applied. In addition, at least one type of glass fiber and at least one type of carbon fiber may be interwoven in combination, since this is excellent in performance, cost, and design.

[0029] Next, the matrix resin to be combined with the reinforcing fibers constituting the plate used in the present invention will be described. As the matrix resin, a thermosetting resin or a thermoplastic resin is preferably used.

[0030] Here, the thermosetting resin is not particularly limited, but is preferably a thermosetting resin composition selected from an epoxy resin composition, a vinyl ester resin composition, an unsaturated polyester resin composition, and a polyurethane resin composition from the viewpoint of handling, and an epoxy resin composition, a vinyl ester resin composition, and an unsaturated polyester resin composition are more preferable from the viewpoint of plate performance and durability. In addition, the thermosetting resin composition containing these does not need to be a single one, and may be mixed with each other, such as by mixing resin compositions together. Here, examples of the epoxy resin composition include resin compositions containing epoxy resins such as aromatic glycidyl ethers obtained from phenols having multiple hydroxyl groups, aliphatic glycidyl ethers obtained from alcohols having multiple hydroxyl groups, glycidyl amines obtained from amines, epoxy resins having oxirane rings, and glycidyl esters obtained from carboxylic acids having multiple carboxyl groups. Examples of aromatic glycidyl ethers include diglycidyl ethers obtained from bisphenols, such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, diglycidyl ether of bisphenol AD, and diglycidyl ether of bisphenol S; polyglycidyl ethers of novolak obtained from phenols and alkylphenols; diglycidyl ether of resorcinol; diglycidyl ether of hydroquinone; diglycidyl ether of 4,4'-dihydroxybiphenyl; and diglycidyl ether of 4,4'-dihydroxy-3, Examples of such diglycidyl ethers include diglycidyl ether of 3',5,5'-tetramethylbiphenyl, diglycidyl ether of 1,6-dihydroxynaphthalene, diglycidyl ether of 9,9'-bis(4-hydroxyphenyl)fluorene, triglycidyl ether of tris(p-hydroxyphenyl)methane, tetraglycidyl ether of tetrakis(p-hydroxyphenyl)ethane, and diglycidyl ethers having an oxazolidone skeleton obtained by reacting diglycidyl ether of bisphenol A with a bifunctional isocyanate.Examples of aliphatic glycidyl ethers include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol, diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, diglycidyl ether of neopentyl glycol, diglycidyl ether of cyclohexanedimethanol, diglycidyl ether of glycerin, triglycidyl ether of glycerin, diglycidyl ether of trimethylolethane, triglycidyl ether of trimethylolethane, diglycidyl ether of trimethylolpropane, triglycidyl ether of trimethylolpropane, tetraglycidyl ether of pentaerythritol, diglycidyl ether of dodecahydrobisphenol A, and diglycidyl ether of dodecahydrobisphenol F. Examples of glycidyl amines include diglycidyl aniline, diglycidyl toluidine, triglycidyl aminophenol, tetraglycidyl diaminodiphenylmethane, tetraglycidyl xylylenediamine, and their halogen-substituted or alkyl-substituted products and hydrogenated products. Examples of epoxy resins having an oxirane ring include vinylcyclohexene dioxide, dipentene dioxide, 3,4-epoxycyclohexane carboxylate 3,4-epoxycyclohexylmethyl, adipate bis(3,4-epoxycyclohexylmethyl), dicyclopentadiene dioxide, bis(2,3-epoxycyclopentyl)ether, and oligomers of 4-vinylcyclohexene dioxide. Examples of glycidyl esters include phthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, and dimer acid diglycidyl ester. The epoxy resin composition does not necessarily contain a single epoxy resin, and a plurality of epoxy resins may be mixed in the epoxy resin composition.

[0031] Examples of vinyl ester resin compositions include resin compositions containing vinyl ester resins such as epoxy acrylate resins obtained by reacting epoxy resins with acrylic acid, or epoxy methacrylate resins obtained by reacting epoxy resins with methacrylic acid. The types of epoxy resins that serve as raw materials for these vinyl ester resins are not particularly limited, but examples include aromatic glycidyl ethers obtained from phenols having multiple hydroxyl groups, aliphatic glycidyl ethers obtained from alcohols having multiple hydroxyl groups, glycidyl amines obtained from amines, epoxy resins having oxirane rings, and glycidyl esters obtained from carboxylic acids having multiple carboxyl groups. Aromatic glycidyl ethers that are the raw material for vinyl ester resins include diglycidyl ethers obtained from bisphenols, such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, diglycidyl ether of bisphenol AD, and diglycidyl ether of bisphenol S; polyglycidyl ethers of novolak obtained from phenols and alkylphenols; diglycidyl ether of resorcinol; diglycidyl ether of hydroquinone; diglycidyl ether of 4,4'-dihydroxybiphenyl; and 4,4'-diglycidyl ether of 4,4'-dihydroxybiphenyl. Examples include diglycidyl ether of hydroxy-3,3',5,5'-tetramethylbiphenyl, diglycidyl ether of 1,6-dihydroxynaphthalene, diglycidyl ether of 9,9'-bis(4-hydroxyphenyl)fluorene, triglycidyl ether of tris(p-hydroxyphenyl)methane, tetraglycidyl ether of tetrakis(p-hydroxyphenyl)ethane, and diglycidyl ethers having an oxazolidone skeleton obtained by reacting diglycidyl ether of bisphenol A with a bifunctional isocyanate.Examples of aliphatic glycidyl ethers that can be used as raw materials for vinyl ester resins include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol, diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, diglycidyl ether of neopentyl glycol, diglycidyl ether of cyclohexanedimethanol, diglycidyl ether of glycerin, triglycidyl ether of glycerin, diglycidyl ether of trimethylolethane, triglycidyl ether of trimethylolethane, diglycidyl ether of trimethylolpropane, triglycidyl ether of trimethylolpropane, tetraglycidyl ether of pentaerythritol, diglycidyl ether of dodecahydrobisphenol A, and diglycidyl ether of dodecahydrobisphenol F. Examples of glycidyl amines that are raw materials for vinyl ester resins include diglycidyl aniline, diglycidyl toluidine, triglycidyl aminophenol, tetraglycidyl diaminodiphenylmethane, tetraglycidyl xylylenediamine, and their halogenated or alkyl substituted products and hydrogenated products. Examples of epoxy resins having an oxirane ring that are raw materials for vinyl ester resins include vinylcyclohexene dioxide, dipentene dioxide, 3,4-epoxycyclohexane carboxylate 3,4-epoxycyclohexylmethyl, adipate bis(3,4-epoxycyclohexylmethyl), dicyclopentadiene dioxide, bis(2,3-epoxycyclopentyl)ether, and oligomers of 4-vinylcyclohexene dioxide. Examples of glycidyl esters that are raw materials for vinyl ester resins include phthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, and dimer acid diglycidyl ester.

[0032] An example of the unsaturated polyester resin composition is a resin composition containing an unsaturated polyester resin obtained by reacting a saturated dibasic acid having two carboxyl groups and no double bond, an unsaturated dibasic acid having a double bond, and a dihydric alcohol having two alcoholic hydroxyl groups. The type of saturated dibasic acid used as the raw material for the unsaturated polyester resin is not particularly limited, but examples thereof include phthalic anhydride and isophthalic acid. The type of saturated unsaturated dibasic acid used as the raw material for the unsaturated polyester resin is not particularly limited, but examples thereof include maleic anhydride and fumaric acid. The type of dihydric alcohol used as the raw material for the unsaturated polyester resin is not particularly limited, but examples thereof include ethylene glycol and propylene glycol.

[0033] The vinyl ester resin composition and the unsaturated polyester resin composition may contain a reactive diluent from the viewpoint of handling such as reducing the viscosity. Examples of the reactive diluent include vinyl monomers such as styrene, vinyl toluene, and methyl methacrylate, allyl monomers such as diallyl phthalate, diallyl isophthalate, and triallyl isocyanurate, acrylic acid esters such as phenoxyethyl (meth)acrylate, 1,6-hexanediol (meth)acrylate, trimethylolpropane tri(meth)acrylate, and 2-hydroxyethyl (meth)acrylate, vinylpyrrolidone, and phenylmaleimide.

[0034] Furthermore, the thermoplastic resin is not particularly limited, but may be polyester such as acrylonitrile butadiene styrene (ABS) resin, polyurethane (TPU) resin, polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polytrimethylene terephthalate (PTT) resin, polyethylene naphthalate (PEN) resin, liquid crystal polyester resin, etc., polyolefin such as polyethylene (PE) resin, polypropylene (PP) resin, polybutylene resin, etc., styrene-based resin, polyoxymethylene (POM) resin, polyamide (PA) resin, polycarbonate (PC) resin, polymethylene methacrylate (PMMA) resin, polyvinyl chloride (PVC) resin, polyphenylene sulfide (PPS) resin, polyphenylene ether (PPE) resin, modified PPE resin, The resin may be a fluorine-based resin such as a polyimide (PI) resin, a polyamide-imide (PAI) resin, a polyetherimide (PEI) resin, a polysulfone (PSU) resin, a modified PSU resin, a polyethersulfone resin, a polyketone (PK) resin, a polyetherketone (PEK) resin, a polyetheretherketone (PEEK) resin, a polyetherketoneketone (PEKK) resin, a polyarylate (PAR) resin, a polyethernitrile resin, a phenolic resin, a phenoxy resin, or a polytetrafluoroethylene resin; further, a thermoplastic elastomer such as a polystyrene-based resin, a polyolefin-based resin, a polyurethane-based resin, a polyester-based resin, a polyamide-based resin, a polybutadiene-based resin, a polyisoprene-based resin, or a fluorine-based resin; or a copolymer, a modified product, or a blend of two or more of these resins.

[0035] In particular, from the standpoint of ease of processability into plates, the required tensile and flexural modulus and strength of the plates, and the design of the plates, the following are preferably used: polymethylene methacrylate (PMMA) resin, polyurethane (TPU) resin, polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, acrylonitrile butadiene styrene (ABS) resin, polyamide (PA) resin (particularly PA6, PA66, and PA12), polycarbonate (PC) resin, and PC / ABS resin, which is a blend of polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) resin.

[0036] Here, when coloring is required as one of the design features of the plate, the color is not particularly limited, but the design can be enhanced by coloring the thermoplastic resins listed above with black, red, yellow, green, blue, purple, brown, etc.

[0037] Next, a fiber reinforced plastic plate (hereinafter referred to as FRP mother plate) that is the base of the plate will be described. The method for obtaining the plate used in the present invention is not particularly limited, but an FRP mother plate having an area larger than the plate is machined to the size of the plate using a machining center, a running saw, a sawing machine, or a water jet.

[0038] Here, the FRP mother board will be explained. The FRP mother board is a fiber reinforced plastic that is integrated by combining the above-mentioned reinforcing fibers and the matrix resin. A unidirectional fiber reinforced plastic in which the above-mentioned reinforcing fibers are aligned in one direction and combined with the above-mentioned matrix resin, or a woven fabric reinforced plastic in which the above-mentioned reinforcing fibers are processed into the above-mentioned fabric and then combined with the above-mentioned matrix resin, is preferably used. The ratio of the reinforcing fibers contained in the unidirectional fiber reinforced plastic or the woven fabric reinforced plastic is not particularly limited, but a volumetric fiber content (Vf) of 5 to 70% is preferably used according to the required rigidity, strength, and cost, and 20 to 70% is preferably used when high rigidity and high strength are required. Note that the volumetric fiber content when multiple reinforcing fibers are applied to one unidirectional fiber reinforced plastic or woven fabric reinforced plastic is calculated by adding up the multiple reinforcing fibers.

[0039] First, a method for manufacturing an FRP mother board when a thermosetting resin is applied to the matrix resin will be described. First, the above-mentioned reinforcing fibers are aligned in one direction, or the above-mentioned reinforcing fibers are processed into the above-mentioned woven fabric, and then a prepreg is manufactured by impregnating the resin. The prepreg can be manufactured by a wet method, a hot melt method, extrusion, spraying, printing, or other known methods for impregnating the resin. In the wet method, the resin is dissolved in an organic solvent selected from acetone, methyl ethyl ketone, and methanol to reduce the viscosity, impregnated into the reinforcing fibers, and then pulled up, and the organic solvent is evaporated using an oven or the like to obtain a prepreg. In the hot melt method, a method in which the matrix resin is directly impregnated into the reinforcing fibers by heating, or a release paper sheet with a resin film (hereinafter sometimes referred to as a "resin film") in which the matrix resin is once coated on a release paper or the like is first produced, and then the resin film is layered on the reinforcing fiber side from both sides or one side of the reinforcing fibers, and the matrix resin is impregnated into the reinforcing fibers by heating and pressurizing can be used. Examples of methods for producing prepregs by the hot melt method include the following methods. The first method is a so-called one-stage impregnation hot melt method in which a resin film containing a resin composition is heated and pressurized from both sides or one side to impregnate the matrix resin in a single stage. The second method is a multi-stage impregnation hot melt method in which a matrix resin is applied to a resin film in multiple stages, and the resin film is impregnated by heating and pressurizing the applied resin from both sides or one side. Here, the thickness of a single sheet of prepreg in which reinforcing fibers are impregnated with resin is not particularly limited, but is preferably in the range of 0.05 mm to 5 mm, and more preferably 0.05 mm to 3 mm from the viewpoint of weight reduction and thinning.

[0040] Next, at least one prepreg obtained by the above-mentioned manufacturing method is laminated to manufacture a prepreg laminate. In this case, the prepreg in which the reinforcing fibers are aligned in one direction and the prepreg in which the reinforcing fibers are processed into a woven fabric may be used alone, or both prepregs may be used in combination. In addition, the lamination angle of each prepreg can be freely selected according to the required stiffness and strength as well as the thickness of the plate. For example, in order to achieve high stiffness and strength in one direction, it is preferable to laminate the prepreg in a direction substantially consistent with other layers. In addition, in order to achieve performance suitable for torsional load and deformation, it is also preferable to laminate the prepreg in a direction 10° to 90° different from at least one other layer. In addition, the thickness of the prepreg laminate is not particularly limited, but is preferably in the range of 0.05 mm to 5 mm, and is preferably in the range of 0.05 mm to 3 mm from the viewpoint of weight reduction and thinning.

[0041] This prepreg laminate is heated and, if necessary, pressurized by press molding, autoclave molding, oven molding, or vacuum oven molding to harden the matrix resin, thereby obtaining an FRP mother board.

[0042] Next, a method for manufacturing an FRP mother board when a thermoplastic resin is applied to the matrix resin will be described. First, after the above-mentioned reinforcing fibers are aligned in one direction, the FRP mother board can be manufactured by a melting method, a powder method, a resin film impregnation method, a mixed weaving method, or other known methods. The melting method is a method in which a thermoplastic resin is melted in an extruder, and the reinforcing fibers are passed through a melt bath to impregnate the inside of the fiber bundle with the resin. The solvent method is a method in which a solution in which a resin is dissolved in a solvent is impregnated into the inside of the fiber bundle. The powder method is a method in which a powder of a thermoplastic resin is attached to the reinforcing fibers, which are then heated to melt and impregnate them. This manufacturing process can produce a prepreg in which the reinforcing fibers are aligned in one direction. On the other hand, at least one of the woven fabric obtained by processing the reinforcing fibers into the above-mentioned woven fabric and the above-mentioned matrix resin processed into a film-like form are simultaneously placed in a pressurizing facility (a so-called press) having a heated metal platen, and the film-like resin is impregnated into the woven fabric by heating and pressing to produce a woven fabric prepreg. Here, the thickness of one sheet of prepreg in which reinforcing fibers are impregnated with resin is not particularly limited, but is preferably in the range of 0.05 mm to 5 mm, and from the viewpoint of weight reduction and thinning, is more preferably 0.05 mm to 3 mm.

[0043] Next, at least one prepreg obtained by the above-mentioned manufacturing method is laminated to manufacture a prepreg laminate. In this case, the prepreg in which the reinforcing fibers are aligned in one direction and the prepreg in which the reinforcing fibers are processed into a woven fabric may be used alone, or both prepregs may be used in combination. In addition, the lamination angle of each prepreg can be freely selected according to the required stiffness and strength as well as the thickness of the plate. For example, in order to achieve high stiffness and strength in one direction, it is preferable to laminate the prepreg in a direction substantially consistent with other layers. In addition, in order to achieve performance suitable for torsional load and deformation, it is also preferable to laminate the prepreg in a direction 10° to 90° different from at least one other layer. In addition, the thickness of the prepreg laminate is not particularly limited, but is preferably in the range of 0.05 mm to 5 mm, and is preferably in the range of 0.05 mm to 3 mm from the viewpoint of weight reduction and thinning.

[0044] This prepreg laminate is integrated by heating and, if necessary, pressurizing using press molding, autoclave molding, oven molding, or vacuum oven molding, and then cooled to obtain an FRP mother board.

[0045] The length and width of the plate used in the present invention can be adjusted according to the desired repulsive force, but the length can also affect the walking comfort. The length of the plate is preferably 2 to 10 cm, and more preferably 4 to 8 cm.

[0046] The plate may have any shape, and examples of the variations are shown in Figs. 3 to 7 and Figs. 9 to 15. Examples include rectangular, bow-shaped, elliptical, circular, triangular, equilateral, wedge-shaped, trapezoidal, arc-shaped, and crescent-shaped. As shown in Fig. 15, the plate may be circular, but in that case, the angle between the long axis of the plate and the PCL is considered to be 0°. In particular, when the plate is rectangular, it is preferable because even a small plate can effectively obtain a repulsive force, and the ratio expressed by the length of the long side / the length of the short side in the case of a rectangle is preferably 2.0 to 5.0, and more preferably 3.0 to 4.0. That is, if this ratio is 2.0 or more, the smooth weight transfer to the forefoot by the plate is less likely to be felt, and if it is 5.0 or less, it is possible to have sufficient strength against deformation in the foot width direction. The corners of this rectangle may be rounded. In addition, it is preferable that the two plates that satisfy conditions 1 to 3 are rectangular with approximately equal widths.

[0047] The stability can be adjusted by placing the plates close to each other or apart on the inner and outer sides of the sole periphery made of a flexible material. In particular, it is preferable to place two plates apart from each other on the inner and outer sides of the sole periphery, and higher stability can be obtained by placing the longer edge of the plate closely along the sole periphery or along the edge of the soft sole material with a small gap of about 0.5 to 1 cm.

[0048] The plate used in the present invention is preferably a fiber-reinforced plastic plate having a width of 1 to 2 cm and a length of 6 to 8 cm, a rectangular plate or a rectangular plate with rounded corners, in which reinforcing fibers are arranged parallel to the long sides of the rectangle, and the reinforcing fibers are preferably continuous from one short side to the other short side of the plate. The use of such a plate is preferable because it can maximize the specific strength and can be easily and efficiently prepared.

[0049] In addition, as shown in Figs. 9 to 12, the plate shape is preferably a triangle. The use of a triangular plate can increase or decrease the level of stability throughout the walking cycle. Specifically, different effects are achieved depending on whether the apex of the triangle is arranged toward the toes or toward the heel. Furthermore, the orientation of the apex of the triangle may be different for the right foot and the left foot. In golf or baseball shoes, for right-handed players, as exemplified in Fig. 9, the apex of the triangle of the right foot is arranged toward the toes, and the apex of the triangle of the left foot is arranged toward the heel, which can efficiently support the body movement involving rotational motion.

[0050] Also, the plate may have holes as shown in Fig. 15. There are no particular restrictions on the shape of the holes, and they may be round or slot-shaped, but by drilling holes, the rigidity of the plate decreases, making it possible to adjust the rigidity.

[0051] The shoe sole of the present invention has at least two plates. A plurality of plates of the same shape may be used, or plates of different shapes may be combined. The number of plates may be three or more, but two is preferable because it simplifies the manufacturing process.

[0052] In the present invention, at least two of the two plates satisfy all of the following conditions 1 to 3. When three or more plates are used, it is not necessary that all combinations of two plates selected from the three or more plates satisfy the following conditions, but it is sufficient that one of the combinations of two plates satisfies the following conditions.

[0053] FIG. 19 shows an example of a combination of four plates. Two rectangular plates are placed above and below the midsole 16, parallel to the PCL (0°). An outsole 15 is layered on the ground side of the midsole, and an insole 19 is layered on the sole side. An upper 20 is also shown as a reference for how the sole is used. The two plates on the ground side (first plate 1, second plate 2) act as a core under the soft midsole, helping the wearer to transfer their weight smoothly. Meanwhile, the two plates on the sole side (third plate 17, fourth plate 18) prevent excessive deformation of the arch of the wearer's foot, helping the wearer to walk with less fatigue.

[0054] The shoe sole of the present invention satisfies the following three conditions, Condition 1 to Condition 3.

[0055] Condition 1: In a perspective view of the bottom of the sole, one of the two plates is positioned on the medial side and the other plate is positioned on the lateral side of the last center line (PCL).

[0056] Condition 2: The long axes of both plates form an angle between 0° and 30° with respect to the PCL.

[0057] Condition 3: When the tip of the toe side of the sole is set to 1 and the tip of the heel side is set to 0, the entirety of both plates must be within the range of 0.2 to 0.7.

[0058] Here, the last center line (PCL, sometimes abbreviated as "PCL" for Profile Center Line) in the bottom perspective view of the sole is determined as the center line of the bottom gauge of the last (wooden model). The angle between the PCL and the long axis of the plate is determined as follows, as shown in FIG. 1. That is, when the sole is viewed from above, the angle is determined as the angle between the long axis of the plate, i.e., the center line of the plate, and the PCL, and when they are parallel, it is zero degrees. Here, the center line of the plate refers to a line connecting the midpoints of the short sides of the circumscribing rectangle with the smallest area that encompasses the plate. When one end of the center line of the plate on the short side of the circumscribing rectangle is P1 and the other end on the short side of the circumscribing rectangle is P2, the distance between P1 and P2 is L1, the distance between P1 and the PCL is LP1, and the distance between P2 and the PCL is LP2, the angle θ between the long axis of the plate, i.e., the center line of the plate, and the PCL is determined from the following (Equation 1).

[0059] sinθ=|LP1-LP2| / L1 (Equation 1) In addition, from the PCL perspective, the side on which the thumb is placed is the medial side, and the side on which the little finger is placed is the lateral side.

[0060] As shown in Fig. 1, the tip of the toe side and the tip of the heel side are obtained as follows. That is, the tip of the toe side is defined as the tangent point of the line of the perpendicular line to the PCL that is tangent to the bottom perspective view of the sole on the toe side, and the tip of the heel side is defined as the tangent point of the line of the perpendicular line to the PCL that is tangent to the bottom perspective view on the heel side. When the tangent point is a line, the center of the tangent part is defined as the tangent point, and when two or more tangent points are observed on the toe side or heel side, the tangent point on that side is the combination that maximizes the distance between the intersection point of the perpendicular line including the tangent point and the PCL, and when the distances are the same, the point on the side where the tangent point is closer to the PCL is adopted.

[0061] In the present invention, when the tip of the toe side of the sole is 1 (indicated as "1.0" in the drawings) and the tip of the heel side is 0 (indicated as "0.0" in the drawings), the two plates are both present in a region of 0.2 to 0.7 as a whole. In addition, to avoid confusion with the drawing symbols, the numbers are written in decimals and in italics in each drawing. In particular, it is preferable that one end of the two plates is present in a region of 0.4 to 0.7 and the other end is present in a region of 0.2 to 0.4. That is, when a point in an XY coordinate system with the PCL as the Y axis and a straight line perpendicular to the PCL and passing through the heel-side tip as the X axis is expressed as (x, y), the y coordinate value of the tip of the toe side is 1 and the y coordinate value of the tip of the heel side is 0, and the two plates do not have any part at a point where the y coordinate value exceeds 0.7 or is below 0.2. In a preferred embodiment, the y coordinate value of one end of the two plates is in the range of 0.4 to 0.7, and the y coordinate value of the other end is in the range of 0.2 to 0.4. Here, the ends of the plates refer to the points on the plates where the y coordinate value is maximum and the points on the plates where the y coordinate value is minimum.

[0062] The present invention does not require special materials or structures in the heel or tip, and only provides limited support to the midfoot region, thereby making it possible to reduce the weight of the entire sole structure.

[0063] Regarding condition 3, when landing, the cushion in the heel part of the sole structure absorbs the impact from the ground and is compressed and deformed, but since one end of the plate is located at a position where the y coordinate value is 0.2 or more, even if the heel of the foot is pronated or supinated and tries to fall sideways when the heel lands, the heel part is less likely to be compressed and deformed as it approaches the midfoot, so that such lateral deviation of the heel can be prevented and stability when weight is transferred from heel landing to the forefoot is also improved. If a part of the plate is located at a position where the y coordinate value is less than 0.2, a feeling of being pushed up may be felt when landing. In addition, since one end of the plate is located at a position where the y coordinate value is 0.7 or less, the foot can be lifted off the ground without inhibiting the dorsiflexion of the toes, especially the MP joints, when the foot is kicked off following the weight transfer to the forefoot. If a part of the plate is located at a y-coordinate value above 0.7, the plate will start to hang under the MTP joint, and beginner runners, especially those without sufficient sole strength, may feel discomfort in the toes or may be hindered from natural dorsiflexion, so it is essential that the plate is within this range. In this way, the two elongated plates arranged approximately parallel to the midfoot act as a kind of guidance system like parallel skiing only when the midfoot touches the ground, allowing even beginner runners to achieve stable weight transfer with a lightweight shoe while suppressing excessive pronation.

[0064] Regarding condition 2, by satisfying condition 2, in addition to the rapid weight transfer during forward movement, the pronation and supination of the ankle joint between the time the heel lands and the time the foot is lifted off can be suppressed, and stabilization can be achieved. The angle of the long axis of the plate to the PCL is preferably within the range of 0° to 10°, more preferably within the range of 0° to 3°. On the other hand, when a side step or a diagonal change of direction is required, the angle of the long axis of the plate to the PCL may be an angle of 10° to 30°. In particular, when the angle is large, it is preferable to arrange the plates on the left and right shoes so that they are mirror images along the edge of the peripheral part of the sole made of a flexible material. When the plate is arranged along the peripheral part of the sole at an angle of 30°, it can be suitably used in sports involving lateral and diagonal movements such as basketball, handball, and soccer. When the angle of the long axis of the plate to the PCL exceeds 30°, the stability of the lateral movement suppression is inferior.

[0065] Furthermore, if the distance between the two plates is too narrow, the plate may lack stability, and the distance between the center of gravity of the plate and the PCL is preferably 1.0 cm to 4.0 cm, and more preferably 2.5 cm to 3.5 cm.

[0066] Furthermore, the shape of the sole of the present invention is not particularly limited, and the stabilizing effect can be expected widely for shoes with sole thickness that are not particularly oversized (thick-soled shoes), such as flat shoes and traditional leather shoes. Among them, it is desirable to have a rocker shape for applications that require easier forward movement. A rocker shape means a shape in which the midfoot part is not raised and either or both the top (tip of the foot) and the tail (rear) are raised. Since there is less surface area in contact with the ground, it is easy to move forward, and since the toes are raised, it is easy to change direction. Rocker-shaped shoes have existed in the past, but there were problems with the durability of the sole due to the lack of a "core", and while it was easy to move forward, there was also the problem of instability under the feet. By inserting a core plate as in the present invention, both durability and stability can be improved.

[0067] In addition, the sole of the present invention has no particular restrictions on the arrangement of the two plates that satisfy conditions 1 to 3 in the height direction within the sole, and there are multiple options. One is on the contact surface with the ground, between the outsole 15 and the midsole 16 as shown in FIG. 20, the lower half of the midsole, the upper half of the midsole, or between the midsole 16 and the insole 19 as shown in FIG. 22. As the arrangement position of the plate in the height direction increases, it approaches the sole of the person's foot, so that the stabilizing effect on the arch of the foot increases, and conversely, the closer it is to the ground, the greater the stability of the shoe when it touches the ground, so that it is possible to adjust which function to focus on. In terms of improving stability between the ground and the shoe, it is preferable that the plates are arranged in a range of 0.05×H or more and 0.5×H or less when the thickness of the sole is H in a cross-sectional view of the vertical cross section of the sole including the center of gravity of the plates, as shown in FIG. 20. It is also preferable that both of the plates are arranged in this range. If the distance from the bottom surface of the sole to the plate is 0.05×H or more of the thickness of the sole in the cross section, the plate can be prevented from being damaged by impact from the ground or by pebbles. If the distance is 0.5×H or less, the impact from the ground can be stably absorbed. The distances from the bottom surface of the sole of the two plates may be the same or different. For example, for a person with overpronation, whose heel rotates inward too much when landing, it is preferable to set the plate on the medial side (arch side) a little higher, and conversely, for a person with underpronation, whose heel falls to the opposite side, it is preferable to set the plate on the lateral side (outside of the foot) a little higher. The thickness H of the sole is to be obtained for each plate at the location of the center of gravity of the plate for which the position in the sole height direction is to be obtained.

[0068] The edge of the plate may be inclined toward the ground. For example, as shown in FIG. 18, the outer side of the outer shell is made higher toward the outside, while the inner side is also made slightly higher toward the outside, which can further increase stability. The edge may be set perpendicular to the ground. This can reduce the amount of plates, and even a narrow plate can provide high rigidity and efficiently achieve stability.

[0069] The plates used in the present invention may be flat, but it is preferable that at least one of them has a shape that bulges out from the ground, as shown in Figure 21. A shape that bulges out from the ground means a shape that has a curved surface that is convex toward the ground, and includes an arch shape. By using such a shape, the area that receives a reaction from the ground during movement can be reduced, making it easier to move forward.

[0070] At least one of the plates used in the present invention is desirably corrugated as shown in Fig. 17. A corrugated shape refers to a plurality of parallelly arranged projections and recesses, and is usually formed by press processing or roll forming. By giving the plate a corrugated shape, a thin and strong structure can be created, and by increasing the bonding area with the midsole or outsole material, the durability of the sole as a whole can be improved, particularly against horizontal displacement of the shoe.

[0071] Example 1: 2 and 20 show the first embodiment.

[0072] As shown in FIG. 2, the first plate 1 and the second plate 2 are disposed in the midfoot and are disposed parallel to the PCL. In addition, when the tip of the toe side of the sole is 1 and the tip of the heel side is 0, the tip of the first plate is disposed at 0.52, the tip of the second plate is disposed at 0.52, the rear end of the first plate is disposed at 0.27, and the rear end of the second plate is disposed at 0.27. The distance between the center of gravity of the first plate and the PCL is 2.7 cm, and the distance between the center of gravity of the second plate and the PCL is 3.0 cm. The plates are made of carbon fiber reinforced plastic, and both the first plate and the second plate are 7.62 cm long, 1.27 cm wide, and 1.27 mm thick, and have a rectangular shape with rounded corners.

[0073] Figure 20As can be seen from the above, the sole of this example has a rocker shape with no lift in the midfoot area and both the top (tip) and tail (rear) raised, and both the first plate and the second plate are positioned between the midsole and the outsole, and are positioned at a height of 0.12×H.

[0074] Example 2: FIG. 3 shows Example 2.

[0075] In FIG. 3, the first plate 1 and the second plate 2 are disposed in the midfoot, and the angle θ between the long axis of the first plate and the PCL is 10°, and the angle θ between the long axis of the second plate and the PCL is 5°. In addition, when the tip of the toe side of the sole is 1 and the tip of the heel side is 0, the tip of the first plate is 0.52, the tip of the second plate is 0.52, the rear end of the first plate is 0.27, and the rear end of the second plate is 0.27. The distance between the center of gravity of the first plate and the PCL is 2.6 cm, and the distance between the center of gravity of the second plate and the PCL is 3.0 cm. The plates are made of carbon fiber reinforced plastic, and both the first plate and the second plate are 7.62 cm long, 1.27 cm wide, and 1.27 mm thick, and have a rectangular shape with rounded corners. As in Example 1, the sole has a rocker shape with no lift in the midfoot area and both the top (tip) and tail (rear) raised, and both the first plate and the second plate are positioned between the midsole and outsole, and are positioned at a height of 0.12 x H.

[0076] Example 3 Figure 4 shows Example 3. In Figure 4, a first plate 1 and a second plate 2 are disposed at the midfoot, and both plates are arc-shaped. Since the shapes are arcs, to find the angle, as shown in Figure 4, a circumscribing rectangle 12 of the first plate and a circumscribing rectangle 13 of the second plate are drawn, and the line connecting the midpoints of the short sides is found to be the plate center line, i.e., the long axis of the plate.

[0077] The angle θ between the long axis of the first plate and the PCL is 0°, and the angle θ between the long axis of the second plate and the PCL is 0°. In addition, when the total length of the sole is 1 and the rear end of the heel is 0, the tip of the first plate is 0.56, the tip of the second plate is 0.56, the rear end of the first plate is 0.25, and the rear end of the second plate is 0.25. The distance between the center of gravity of the first plate and the PCL is 3.5 cm, and the distance between the center of gravity of the second plate and the PCL is 3.5 cm. The plates are made of carbon fiber reinforced plastic, and the circumscribing rectangle 12 of the first plate and the circumscribing rectangle 13 of the second plate are both 9.30 cm long and 1.62 cm wide, and the thickness of both the first plate and the second plate is 1.27 mm. As in Example 1, the sole has a rocker shape with no lift in the midfoot area and both the top (tip) and tail (rear) raised, and both the first plate and the second plate are positioned between the midsole and outsole, and are positioned at the same 0.12×H position in the height direction as in Example 1.

[0078] Example 4 FIG. 5 shows Example 4.

[0079] In FIG. 5, the first plate and the second plate are disposed in the midfoot, and the angle θ between the long axis of the first plate and the PCL is 17°, and the angle θ between the long axis of the second plate and the PCL is 8.5°. When the total length of the sole is 1 and the rear end of the heel is 0, the tip of the first plate is 0.61, the tip of the second plate is 0.70, the rear end of the first plate is 0.37, and the rear end of the second plate is 0.20. The distance between the center of gravity of the first plate and the PCL is 3.5 cm, and the distance between the center of gravity of the second plate and the PCL is 3.6 cm. The plates are made of carbon fiber reinforced plastic, and the first plate is 7.62 cm long and 1.27 cm wide, and the second plate is 15.5 cm long and 1.27 cm wide, and both are 1.27 mm thick, and have a rectangular shape with rounded corners. As in Example 1, the sole has a rocker shape with no lift in the midfoot area and both the top (tip) and tail (rear) raised, and both the first plate and the second plate are positioned between the midsole and outsole, and are positioned at 0.12 x H in the height direction, the same as in Example 1.

[0080] Example 5 FIG. 6 shows Example 5.

[0081] As shown in FIG. 6, the first plate 1 and the second plate 2 are disposed in the midfoot and are disposed parallel to the PCL. In addition, when the tip of the toe side of the sole is 1 and the tip of the heel side is 0, the tip of the first plate is disposed at 0.52, the tip of the second plate is disposed at 0.52, the rear end of the first plate is disposed at 0.27, and the rear end of the second plate is disposed at 0.27. The distance between the center of gravity of the first plate and the PCL is 1.6 cm, and the distance between the center of gravity of the second plate and the PCL is 1.6 cm. The plates are made of carbon fiber reinforced plastic, and both the first plate and the second plate are 7.62 cm long, 1.27 cm wide, and 1.27 mm thick, and have a rectangular shape with rounded corners. As in Example 1, the sole has a rocker shape with no lift in the midfoot area and both the top (tip) and tail (rear) raised, and both the first plate and the second plate are positioned between the midsole and outsole, and are positioned at a height of 0.12 x H.

[0082] Example 6 FIG. 7 shows Example 6.

[0083] As shown in FIG. 7, the first plate 1 and the second plate 2 are disposed in the midfoot and are disposed parallel to the PCL. In addition, when the tip of the toe side of the sole is 1 and the tip of the heel side is 0, the tip of the first plate is disposed at 0.52, the tip of the second plate is disposed at 0.52, the rear end of the first plate is disposed at 0.27, and the rear end of the second plate is disposed at 0.27. The distance between the center of gravity of the first plate and the PCL is 0.99 cm, and the distance between the center of gravity of the second plate and the PCL is 0.99 cm. The plates are made of carbon fiber reinforced plastic, and both the first plate and the second plate are 7.62 cm long, 1.27 cm wide, and 1.27 mm thick, and have a rectangular shape with rounded corners. As in Example 1, the sole has a rocker shape with no lift in the midfoot area and both the top (tip) and tail (rear) raised, and both the first plate and the second plate are positioned between the midsole and outsole, and are positioned at a height of 0.12 x H.

[0084] Comparative Example 1 A plateless sole with a rocker-shaped EVA midsole.

[0085] Comparative Example 2 In FIG. 8, the first plate and the second plate are disposed in the midfoot and are disposed parallel to the PCL. In addition, when the total length of the sole is 1 and the rear end of the heel is 0, the tip of the first plate is disposed at 0.70, the tip of the second plate is disposed at 0.70, the rear end of the first plate is disposed at 0.16, and the rear end of the second plate is disposed at 0.16. The distance between the center of gravity of the first plate and the PCL is 3.5 cm, and the distance between the center of gravity of the second plate and the PCL is 3.5 cm. The plates are made of carbon fiber reinforced plastic, and both the first plate and the second plate are 16.5 cm long, 1.27 cm wide, and 1.27 mm thick, and have a rectangular shape with rounded corners.

[0086] The sole has a rocker shape with no lift in the midfoot area and both the top (tip) and tail (rear) raised, and the first plate and the second plate are both positioned between the midsole and outsole, and are positioned at a height of 0.12 x H.

[0087] Details of the items measured in each experiment are as follows:

[0088] Exercise condition 1 (running): Eight male subjects wore shoes using the soles of each embodiment and comparative example and ran on a floor reaction force recorder at a pace of 8 minutes / mile. The floor reaction force (N / kg) for the impact at heel landing (impact at heel landing), the propulsive force of kicking off (propulsive force of kicking off), and the stability of left and right swing from landing to foot lifting (stability) were measured, and the average of the eight subjects was used. The smaller the floor reaction force for the impact at heel landing, the better, which means excellent shock absorption. In addition, the smaller the floor reaction force, which corresponds to the stability of left and right swing until foot lifting, the better. On the other hand, the greater the propulsive force of kicking off, the better the shoe characteristics.

[0089] Exercise condition 2 (walking): Eight male subjects walked wearing shoes with soles made from each of the examples and comparison examples, and the impact when the heel strikes the ground (impact when the heel strikes the ground), the propulsive force of the push-off (propulsive force of the push-off), and the sense of stability of left and right sway from landing to lifting the foot (stability) were measured, as well as the floor reaction force (N / kg).

[0090] Subjective evaluation: A questionnaire was given to the above eight male subjects, who were then given scores for the following items, and the average score for the eight subjects was calculated for each Example and Comparative Example. The items were overall comfort, cushioning at heel strike, and cushioning in the forefoot. Scoring was 4: acceptable, with seven levels of scores: 3: poor, 2: very poor, 1: fairly poor, 5: good, 6: very good, and 7: extremely good.

[0091] Table 1 summarizes the plate arrangement relationship in the examples and comparative examples.

[0092] Table 2 shows the test results for exercise conditions 1 and 2.

[0093] Table 3 shows the subjective evaluation scores by eight subjects.

[0094] [Table 1-1]

[0095] [Table 1-2]

[0096] [Table 2-1]

[0097] [Table 2-2]

[0098] [Table 3]

[0099] It can be seen from Table 2 that the examples of the present invention have a smaller impact when the heel lands compared to the comparative examples, do not impair the propulsive force of the push-off, and are excellent in stability (particularly when walking) from landing to lifting off. Also, as shown in Table 3, the subjective evaluation was also superior to the comparative examples. It can be seen that the examples are excellent in stability and quick weight transfer in the desired direction under each exercise condition. [Industrial Applicability]

[0100] The present invention is lightweight and comfortable to wear, making it suitable for use around town, and is also suitable for a wide range of sports including, but not limited to, running and jogging, golf, tennis, basketball, soccer, and skateboarding. [Explanation of symbols]

[0101] 1. Plate (first plate) 2. Plate (second plate) 3. PCL 4.P1 5.P2 6.Plate centerline 7.L1 8.LP1 9.LP2 10.θ 11. Tip of the toes 12. Tip of the heel 13. Circumscribing rectangle of first plate 14. Circumscribing rectangle of the second plate 15. Outsole 16. Midsole 17. Plate (third plate) 18. Plate (fourth plate) 19. Insoles 20. Upper 21. Shoe sole contact surface 22. The upper sole of the shoe sole corresponding to the arrangement position of plate 2

Claims

1. The sole comprises at least a sole body made of a flexible material and a plate made of a material having a higher flexural modulus than the flexible material constituting the sole body, wherein at least two of the plates are included in the sole body, and two of the plates satisfy all of the following conditions 1 to 3. Condition 1: In a bottom perspective view of the sole, one of the two plates is positioned independently on the medial side and the other on the lateral side with respect to the last center line (hereinafter referred to as "PCL"). Condition 2: The long axes of the two plates both form an angle in the range of 0° to 30° with respect to the PCL. Condition 3: When the tip of the toe side of the sole is 1 and the tip of the heel side is 0, the two plates in question are both entirely within the range of 0.2 to 0.7, with one end of the plates being within the range of 0.4 to 0.7 and the other end being within the range of 0.2 to 0.

4.

2. 2. The shoe sole according to claim 1, wherein the shape of the sole is a rocker shape.

3. 2. The sole according to claim 1, wherein the two plates are both arranged in a range of 0.05×H or more and 0.5×H or less, when viewed in a vertical cross section of the sole including the major axis of the plate, where H is the thickness of the sole.

4. The shoe sole according to claim 1 , wherein at least one of the two plates has a shape that bulges outward from the ground.

5. The shoe sole according to claim 1 , wherein at least one of the two plates has a corrugated shape.

6. 2. The sole according to claim 1, wherein the material having a flexural modulus higher than that of the flexible material constituting the sole body is a fiber-reinforced plastic.

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