Patent Publication Number: US-7712231-B2

Title: Shoe

Description:
This application claims priority based on Japanese Patent Application No. 2005-332893 filed on Nov. 17, 2005. All the contents in the Japanese Patent Application are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to shoes suitable for golf, tennis, squash, field hockey, basketball, aerobic exercise or the like. 
     2. Description of the Related Art 
     A shoe comprises an outsole, midsole, insole, upper or the like. A midsole comprises a polymer form including air bubbles. As a base polymer, ethylene-vinyl acetate copolymer (EVA) is used for a normal midsole. A midsole contributes to shock absorbability. JP-U-H2-134003 discloses a shoe comprising a multilayer-structured midsole and being superior in shock absorbability and traction. 
     When hitting a golf ball, a golf player sets an address such that a line connecting the right and the left is almost parallel with a the hitting direction. At the address, the head of a golf club is positioned close to the golf ball. The golf player starts the take-back, pulls the golf club head backward and then swings the golf club upward. The highest position of the head swung upward is referred to as the “top position”. From the top position, the down swing is started and the golf club head is swung downward so that the head impacts the golf ball. After the impact, the golf player swings the right-handed golf club leftward, then follows and finally finishes. 
     From the top position to the finish, the golf player turns the body by setting the left foot as a pivot. At the same time, the golf player kicks the ground with the right foot to transfer the force to the golf ball. In other words, a right-handed golf player uses the left foot as a pivoting foot and the right foot as a kicking foot. A left-handed golf player uses the right foot as a pivoting foot and the left foot as a kicking foot. 
     During the swing, the golf player kicks the ground while applying his or her own body weight to the inside of the kicking foot. The golf player receives his or her own body weight mainly on the inside of the pivoting foot. At this time, force is transferred to the ground via the shoe. A shoe suitable for a golf swing is desired. 
     Also in various sports, a movement in which a player&#39;s body weight is applied to the inside of a foot is observed. In tennis and squash, when a racket is swung, a player&#39;s body weight is applied to the inside of a foot. In field hockey, when a stick is swung, a player&#39;s body weight is applied to the inside of a foot. In basketball and aerobics exercise, a player&#39;s body weight is applied to the inside of a foot during both clockwise and anticlockwise body turns. In these sports, a shoe suitable for movement is desired. 
     The object of the present invention is to provide a shoe in which a wearer&#39;s body weight is easily applied to the inside of a foot. 
     SUMMARY OF THE INVENTION 
     A shoe according to the present invention comprises a bottom part. When the body weight of a wearer is applied to the top surface of the bottom part, downward displacement of the inside of the top surface is larger than downward displacement of the outside of the top surface. 
     In the shoe according to the present invention, when the body weight is applied, the top surface of the bottom part is inclined upward from the inside to the outside. This inclination enables the wearer to apply the body weight to the inside of the foot more easily. 
     Another shoe according to the present invention comprises a bottom part including a midsole. This midsole has a low elastic part, a high elastic part and an inclined surface. There is a low elastic part to the inside of the inclined surface and there is a high elastic part to the outside of the inclined surface. When the body weight of a wearer is applied to the top surface of this bottom part, downward displacement of the inside of the top surface is larger than downward displacement of the outside of the top surface. 
     It is preferable that there is a high elastic part to the inside of the low elastic part. It is preferable that the thickness of the low elastic part becomes gradually larger along the inclined surface in the direction from the outside to the inside. It is preferable that the thickness of the high elastic part becomes gradually larger along the inclined surface in the direction from the inside to the outside. It is preferable that the above-mentioned inclined surface exists at a place of 25% from the tiptoe end toward the heel end. It is preferable that the width of the inclined surface in the left and right directions is 5 mm or more and 100 mm or less. It is preferable that the maximum thickness along the inclined surface of the low elastic part is 30% or more of the thickness of the midsole. It is preferable that the inclined surface is inclined upward in the direction from the inside to the outside. It is preferable that the ratio (HL/HH) of the hardness HL of the above-mentioned low elastic part to the hardness HH of the above-mentioned high elastic part is 0.20 or more and 0.90 or less. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially-cutout side view showing a golf shoe according to an embodiment of the present invention, 
         FIG. 2  is a plan view showing a midsole of a golf shoe illustrated in  FIG. 1 , 
         FIG. 3  is an expanded cross-sectional view taken along the line III-III in  FIG. 2   
         FIG. 4  is an expanded cross-sectional view taken along the line IV-IV in  FIG. 2 , 
         FIG. 5  is an expanded cross-sectional view taken along the line V-V in  FIG. 2 , 
         FIG. 6  is a cross-sectional view explaining an example of a manufacturing method of the midsole illustrated in  FIG. 2 , 
         FIG. 7  is a cross-sectional view explaining another example of a manufacturing method of the midsole illustrated in  FIG. 2 , 
         FIG. 8  is a cross-sectional view showing a midsole of a golf shoe according to a further embodiment of the present invention, 
         FIG. 9  is a cross-sectional view showing a midsole of a golf shoe according to a further embodiment of the present invention, 
         FIG. 10  is a cross-sectional view showing a midsole of a golf shoe according to a further embodiment of the present invention, 
         FIG. 11  is a cross-sectional view showing a midsole of a golf shoe according to yet another embodiment of the present invention, 
         FIG. 12  is a plan view showing a midsole of a golf shoe according to a further embodiment of the present invention, 
         FIG. 13  is a plan view showing a midsole of a golf shoe according to a further embodiment of the present invention, 
         FIG. 14  is a plan view showing a midsole of a golf shoe according to a further embodiment of the present invention, 
         FIG. 15  is a cross-sectional view showing a midsole of a golf shoe according to Example 9 of the present invention, and 
         FIG. 16  is a cross-sectional view showing a midsole of a golf shoe according to a comparative example. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will be described below in detail based on a preferred embodiment with reference to the drawings. 
     A golf shoe  2  illustrated in  FIG. 1  comprises an upper  4  and a bottom part  6 . The bottom part  6  has an insole  8 , a midsole  10  and an outsole  12 . The insole  8  is laminated with the midsole  10 . The midsole  10  is laminated with the outsole  12 . The outsole  12  has a number of projections  14  protruding downward on the lower surface. The material and structure for the upper  4  are equal to those of known upper. The material and structure for the insole  8  are equal to those of known insole. The material and structure for the outsole  12  are equal to those of known outsole. 
     As shown in  FIG. 2  to  FIG. 5 , the midsole  10  has a base  16  and a side wall  18  which is located on the outer edge of this base  16 . This midsole  10  is designed for a right foot. The shape of the midsole for a left foot is a mirror-reversed shape of the shape illustrated in  FIG. 2 . In  FIG. 3  to  FIG. 5 , the left side direction indicates an inside direction and the right side direction indicates an outside direction. 
     The midsole  10  comprises a polymer form including air bubbles. A typical base polymer of the midsole  10  is an ethylene-vinyl acetate (EVA). A vinyl acetate content of EVA is preferably 10 mass % or more and more preferably 15 mass % or more. The vinyl acetate content of EVA is preferably 40 mass % or less, more preferably 30 mass % or less and particularly preferably 25 mass % or less. It is preferable that an EVA and a polyolefin are used in combination as a base polymer for the midsole. The polyolefin contributes to shock absorbability and rebound performance. From this point, the amount of polyolefin to the total amount of the base polymer is preferably 5 mass % or more and more preferably 10 mass % or more. From the cost and adhesive performance standpoints, the amount of polyolefin is preferably 80 mass % or less, more preferably 70 mass % or less and particularly preferably 15 mass % or less. The preferable polyolefin include an ethylene-octane copolymer, an ethylene-butene copolymer, polypropylene and a polyethylene. 
     The midsole  10  may include independent air bubbles or may include continuous air bubbles. From the view point of the shape recovery force and non-absorption property, it is preferable that independent air bubbles are included. Air bubbles are formed in general by foaming of thermally-decomposed foaming agent. As a thermally-decomposed foaming agent, an azo compound (for example, an azodicarbonamide), nitroso compound (for example, dinitrosopentamethylenetetramine) and a triazole compound are shown. An expansion rate of the midsole  10  is preferably 2 times or more and more preferably 3 times or more. Furthermore, the expansion rate is preferably 30 times or less, more preferably 15 times or less and particularly preferably 10 times or less. 
     This midsole  10  has a low elastic part  20  and a high elastic part  22 . The elastic modulus of the low elastic part  20  is lower than that of the high elastic part  22 . When a compression load is applied to the midsole  10 , the low elastic part  20  is more easily deformed than the high elastic part  22 . The low elastic part  20  may comprise two (2) or more parts having different elastic moduli. The high elastic part  22  may comprise two (2) or more parts having different elastic moduli. 
     Furthermore, this midsole  10  has an inclined surface  24 . The inclined surface  24  forms a part of a boundary between the low elastic part  20  and the high elastic part  22 . The inclined surface  24  is inclined along the horizontal directions. In this embodiment, the inclined surface  24  is inclined upward from the left (the inside) to the right (the outside). The low elastic part  20  is located on the upper side of the inclined surface  24 . The low elastic part  20  is located to the inside of the inclined surface  24 . The high elastic part  22  is located to the lower side of the inclined surface  24 . The high elastic part  22  is located to the outside of the inclined surface  24 . The high elastic part  22  is also located to the inside of the low elastic part  20 . A high elastic part  22  which is located to the inside of the low elastic part  20  is hereinafter referred to as “inner high elastic part  26 ”. The thickness of the low elastic part  20  becomes gradually larger along the inclined surface  24  from the outside to the inside. The thickness of the high elastic part  22  becomes gradually larger along the inclined surface  24  from the inside to the outside. 
     When a golf player wears these golf shoes  2  and the body weight of the golf player is applied to the bottom part  6 , this midsole  10  is compressed. Since the thickness of the low elastic part  20  is larger in the inside, the inside compression deformation is larger. Since the thickness of the high elastic part  22  is larger in the outside, outside compression deformation is smaller. In this midsole  10 , applying the body weight generates unbalanced deformation. Deformation of the midsole  10  displaces the position of an upper surface  28  ( FIG. 1 ) of the insole  8 . The downward displacement of the upper surface  28  in the inside is larger than the downward displacement of the upper surface  28  in the outside. The insole  8  inclines upward from the inside to the outside. The foot of a golf player also inclines upward from the inside to the outside. The body weight of a golf player is mainly applied to the inside. As mentioned above, when a golf player swings, the golf player kicks the ground with the inside of the kicking foot. Since the foot is inclined, the golf player easily transfers the force to the ground. This midsole  10  is suitable for the right foot of a right-handed golf player. These golf shoes  2  contribute to generation of high head speed. The large head speed generates a long flight distance. 
     Even if the body weight of a golf player is applied to the bottom part  6 , the inner high elastic part  26  is not deformed so much. This inner high elastic part  26  does not absorb a force transferred from the foot to the ground so much. A large amount of force is transferred from the foot to the ground through this inner high elastic part  26 . This inner high elastic part  26  contributes to generation of great head speed. 
     A midsole having a mirror-reversed shape of the midsole in  FIG. 3  is suitable for a pivoting foot of a right-handed golf player (that is, the left foot). This midsole inclines the pivoting foot of the golf player upward from the inside to the outside. The gold player tends to receive the body weight on the pivoting foot. This midsole also contributes to long flight distance. 
     In the present invention, the state where the body weight is applied on means that the state where a wearer whose weight is 60 kg applies the weight to the right and left feet uniformly. 
     It is preferable that unbalanced deformation is achieved in both the midsole for the left foot and the midsole for the right foot. The unbalanced deformation may be achieved in either the midsole for the left foot or the midsole for the right foot. 
     In this midsole  10 , thickness of the low elastic part  20  and high elastic part  22  gradually changes along the inclined surface  24 . Accordingly, the compression deformation in the midsole  10  changes continuously along the inclined surface  24  from the inside to the outside. The compression deformation does not change rapidly. The continuous change contributes to stability of swing. A stable swing suppresses variation of flight distance. Furthermore, a stable swing suppresses variation of flight direction of a golf ball. The midsole  10  whose compression deformation changes continuously does not cause discomfort during walking. 
     By applying large expansion rate to the low elastic part  20  and small expansion rate to the high elastic part  22 , a difference between elastic moduli can be achieved. By using a base polymer for the high elastic part  22  and another base polymer for the low elastic part  20 , a difference between elastic moduli can be achieved By adding an amount of an additive agent which is different from the amount of the high elastic part  22  into the low elastic part  20 , a difference between elastic moduli can be achieved. By mixing an additive agent into the low elastic part  20  and another additive agent into the high elastic part  22 , a difference between elastic moduli can be achieved. 
     As clearly shown in  FIG. 2 , the planar shape of the low elastic part  20  is substantially ellipse. In the midsole  10  having the elliptical low elastic part  20 , the compression deformation does not change rapidly even in a back and forth direction. The elliptical low elastic part  20  contributes to stability of swing. A low elastic part whose planar shape is elongated circle also contributes to stability of swing. 
     A chain double-dashed line designated by a reference numeral A in  FIG. 2  is a longitudinal line of the midsole  10 . The longitudinal line A is the longest segment that can be drawn within a contour of the midsole  10 . The longitudinal line A extends from the tiptoe end  30  to the heel end  32 . In  FIG. 2 , the length of the longitudinal line A is designated by a reference numeral L. A chain double-dashed line designated by a reference numeral B in  FIG. 2  is a lateral line. The lateral line B is at right angles to the longitudinal line A. The distance from the tiptoe end  30  to the lateral line B is (L/4). The lateral line B passes through the low elastic part  20 . In other words, the inclined surface  24  is located at the place of 25% of the distance L from the tiptoe end  30  to the heel end  32  along the longitudinal line A. The position to which the maximum loads are applied during swinging is the vicinity of the ball of the thumb. The inclined surface  24  is located on the above-mentioned position, which allows a golf player to transfer the force to the ground easily. The length L is from 150 mm to 320 mm in general. 
     From the point of view that the force is easily transferred to the ground by a golf player, the distance of the inclined surface  24  along the longitudinal line A is preferably 5 mm or more, more preferably 20 mm or more, and particularly preferably 50 mm or more. From the effect standpoint, the upper limit of this distance is not designated. However, it is usually 200 mm or less, or furthermore, 105 mm or less. 
     The length designated by both-oriented arrow Wa in  FIG. 4  is the width of the inclined surface  24  in the left and right directions. The width Wa is measured on a cross-section surface along the lateral line B. The width Wa is preferably 5 mm or more and 100 mm or less. By setting the width Wa to be 5 mm or more, rapid change of compression deformation is suppressed. From this viewpoint, the width Wa is more preferably 20 mm or more and particularly preferably 30 mm or more. In the golf shoes  2  whose width Wa is set to be 100 mm or less, a golf player transfers the force to the ground easily. From this viewpoint, the width Wa is more preferably 80 mm or less and particularly preferably 70 mm or less. The width W of the midsole  10  along the lateral line B is 80 mm or more and 120 mm or less in general. 
     The length designated by both-oriented arrow Wb in  FIG. 4  is a width of a flat top surface of the inner high elastic part  26 . The width Wb is measured along the lateral line B. The width Wb is preferably 3 mm or more and 25 mm or less. By setting the width Wb to be 3 mm or more, sufficient force is transferred from the foot to the ground. From this viewpoint, the width Wb is more preferably 5 mm or more, still more preferably 7 mm or more and particularly preferably 10 mm or more. By setting the width Wb to be 25 mm or less, the foot is sufficiently inclined. From this viewpoint, the width Wb is more preferably 22 mm or less and particularly preferably 18 mm or less. 
     The length designated by both-oriented arrow Wc in  FIG. 4  is a width of the inner high elastic part  26 . The width Wc is measured along the lateral line B. The width Wc is preferably 13 mm or more and 35 mm or less. By setting the width Wc to be 13 mm or more, sufficient force is transferred from the foot to the ground. From this viewpoint, the width Wc is more preferably 15 mm or more, still more preferably 17 mm or more and particularly preferably 20 mm or more. By setting the width Wc to be 35 mm or less, the foot is sufficiently inclined. From this viewpoint, the width Wc is more preferably 32 mm or less and particularly preferably 28 mm or less. 
     The length designated by both-oriented arrow Wd in  FIG. 4  is a distance between the outside end of the low elastic part  20  and the outside end of the midsole. The distance Wd is preferably 13 mm or more, more preferably 15 mm or more, still more preferably 17 mm or more and particularly preferably 20 mm or more. The distance Wd is preferably 35 mm or less, more preferably 32 mm or less and particularly preferably 28 mm or less. 
     The length designated by both-oriented arrow T in  FIG. 4  is the thickness of the midsole  10 . The thickness T is measured on a cross-section surface along the lateral line B. The thickness T is the maximum thickness among the parts except for the side wall  18 . The thickness T is preferably 2 mm or more and more preferably 5 mm or more. The thickness T is preferably 25 mm or less, more preferably 20 mm or less and particularly preferably 15 mm or less. The length designated by both-oriented arrow t in  FIG. 4  is the maximum thickness of the low elastic part  20 . The thickness t is measured on a cross-section surface along the lateral line B. From the viewpoint that the top surface of the insole  8  is sufficiently inclined, the ratio of the thickness t to the thickness T is preferably 30% or more, more preferably 40% or more, still more preferably 50% or more, and particularly preferably 80% or more. In the embodiment shown in  FIG. 4 , this ratio is designed to be 100%. In other words, the low elastic part  20  is slightly exposed on the bottom surface  34  of the midsole  10 .  FIG. 3  clearly shows that the low elastic part  20  is not exposed on the bottom surface  34  on a cross-section surface along III-III line.  FIG. 5  clearly shows that the low elastic part  20  is not exposed on the bottom surface  34  on a cross-section surface along V-V line. 
     If there is a boundary between the low elastic part  20  and the high elastic part  22  on the bottom surface  34 , this boundary may cause damage such as a crack or the like. From the standpoint of durability of the midsole  10 , it is preferable that there is no boundary on the bottom surface  34 . In other words, it is preferable that the low elastic part  20  is not exposed on the bottom surface  34 . From the standpoint of durability, the ratio of the thickness t to the thickness T is preferably less than 100%, more preferably 98% or less and particularly preferably 95% or less. 
     The angle designated by both-oriented arrows θ in  FIG. 4  is the angle of the inclined surface  24  to the left and right directions (horizontal direction). The angle θ is measured on a cross-sectional surface along the lateral line B. The angle θ is preferably 3 degrees or more and 60 degrees or less. In the golf shoes  2  whose angle θ is set to be 3 degrees or more, a force can be easily transferred to the ground by a golf player. From this viewpoint, the angle θ is more preferably 5 degrees or more and particularly preferably 7 degrees or more. By setting the angle θ to be 60 degrees or less, rapid change in compression deformation is suppressed. From this viewpoint, the angle θ is more preferably 50 degrees or less, more preferably 40 degrees or less and particularly preferably 20 degrees or less. 
     The ratio (HL/HH) of the hardness HL of the low elastic part  20  to the hardness HH of the high elastic part  22  is preferably 0.20 or more and 0.90 or less. By setting the ratio (HL/HH) to be 0.20 or more, rapid change in compression deformation can be suppressed. From this viewpoint, the ratio (HL/HH) is more preferably 0.3 or more and particularly preferably 0.40 or more. By setting the ratio (HL/HH) to be 0.90 or less, a force can be easily transferred to the ground by a golf player. From this viewpoint, the ratio (HL/HH) is more preferably 0.85 or less and particularly preferably 0.80 or less. The hardness HL of the low elastic part  20  is preferably 20 or more and 70 or less. The hardness HH of the high elastic part  22  is preferably 40 or more and 85 or less. The hardness in conformity to the Society of Rubber Industry, Japan Standard is measured by an Asker C hardness meter of Kobunshi Keiki Co., Ltd. 
       FIG. 6  is a cross-sectional view explaining an example of a manufacturing method for the midsole  10  in  FIG. 2 . In this manufacturing method, a first component  36 , a second component  38  and a third component  40  are prepared. Each of the first component  36 , the second component  38  and the third component  40  is polymer former including air bubbles. The elastic modulus of the first component  36  is smaller than that of the second component  38  and the third component  40 . The cross-sectional shape of the first component  36  and the second component  38  is substantially a triangle. The contour of the third component  40  is similar to that of the midsole  10 . The third component  40  has a hole  42  formed by blanking. 
     In this manufacturing method, the first component  36  is attached to the second component  38 . The boundary between the first component  36  and the second component  38  is inclined. Next, the first component  36  and the second component  38  are inserted into the hole  42  of the third component  40 . Next, the first component  36 , the second component  38  and the third component  40  are placed into a mold and compressed under high temperature. Each component  36 ,  38  and  40  is joined with each other. In this manufacturing method, the first component  36  forms the low elastic part  20  and the second component  38  and the third component  40  form the high elastic part  22 . After the first component  36  and the second component  38  are compressed, and the third component  40  is also compressed, the first component  36  and the second component  38  may be inserted into this third component  40 . 
       FIG. 7  is a cross-sectional view explaining another example of a manufacturing method of the midsole  10  in  FIG. 2 . In this method, a first component  44  and a second component  46  are prepared. Each of the first component  44  and the second component  46  is a polymer former including air bubbles. The first component  44  and the second component  46  are already compressed. The elastic modulus of the first component  44  is smaller than that of the second component  46 . The cross-sectional shape of the first component  44  is substantially a triangle. The contour of the second component  46  is similar to that of the midsole  10 . The second component  46  has a recessed part  48 . The cross-sectional shape of the recessed part  48  is virtually a triangle. The top surface  50  of the recessed part  48  is inclined. 
     In this manufacturing method, the first component  44  is inserted into the recessed part  48  of the second component  46  and both components are attached. The boundary between the first component  44  and the second component  46  is inclined. In this manufacturing method, the first component  44  forms the low elastic component  20  and the second component  46  forms the high elastic component  22 . 
     By providing the outsole  12  with a low elastic part and a high elastic part, inclination of a foot may be achieved. By designing the density of the projection  14  in the inside smaller than the density of the projection  14  in the outside, inclination of a foot may be achieved. 
       FIG. 8  is a cross-sectional view showing a midsole  50  of a golf shoe according to another embodiment of the present invention. The planar shape of this midsole  50  is equal to that of the midsole  10  shown in  FIG. 2 .  FIG. 8  shows a cross-sectional surface along the lateral line B. In  FIG. 8 , the left side direction indicates an inside direction and the right side direction indicates an outside direction. This midsole  50  has a low elastic part  54 , a high elastic part  56  and an inclined surface  58 . The cross-sectional shape of the low elastic part  54  is substantially trapezoidal. The lower elastic part  54  is located to the upper side of the inclined surface  58 . The lower elastic part  54  is located to the inside of the inclined surface  58 . The high elastic part  56  is located to the lower side of the inclined surface  58 . The high elastic part  56  is located to the outside of the inclined surface  58 . An inner high elastic part  60  is located to the inside of the low elastic part  54 . 
     Also in this midsole  50 , a foot is inclined due to a difference of compression deformation of the low elastic part  54  and the high elastic part  56 . Through this inclination, a golf player can transfer sufficient force to the ground. Also in this midsole  50 , compression deformation changes continuously from the inside to the outside along the inclined surface  58 . The continuous change contributes to stability of swing. The inner high elastic part  60  does not absorb much of the force transferred from a foot to the ground. 
       FIG. 9  is a cross-sectional view showing a midsole  62  of a golf shoe according to a further embodiment of the present invention. The planar shape of this midsole  62  is equal to that of the midsole  10  shown in  FIG. 2 .  FIG. 9  shows a cross-sectional surface along the lateral line B. In  FIG. 9 , the left side direction indicates an inside direction and the right side direction indicates an outside direction. This midsole  62  has a low elastic part  64 , a high elastic part  66 , an inclined surface  68  and a flat surface  70 . The flat surface  70  is continuously connected to the inclined surface  68  and is located to the outside of the inclined surface  68 . The low elastic part  64  is located to the upper side of the inclined surface  68 . The low elastic part  64  is located to the inside of the inclined surface  68 . The high elastic part  66  is located to the lower side of the inclined surface  68 . The high elastic part  66  is located to the outside of the inclined surface  68 . The low elastic part  64  is on the flat surface  70 . The high elastic part  66  is under the flat surface  70 . An inner high elastic part  72  is located to the inside of the low elastic part  64 . 
     Also in this midsole  62 , a foot is inclined due to a difference of compression deformation between the low elastic part  64  and the high elastic part  66 . Through this inclination, a golf player can transfer sufficient force to the ground. Also in this midsole  62 , the compression deformation changes continuously from the inside to the outside along the inclined surface  68 . The continuous change contributes to stability of swing. Also in this midsole  62 , the inner high elastic part  72  does not absorb much of the force transferred from a foot to the ground. 
       FIG. 10  is a cross-sectional view showing a midsole  74  of a golf shoe according to a further embodiment of the present invention. The planar shape of this midsole  74  is equal to that of the midsole  10  shown in  FIG. 2 .  FIG. 10  shows a cross-sectional surface along the lateral line B. In  FIG. 10 , the left side direction indicates an inside direction and the right side direction indicates an outside direction. The midsole  74  has a low elastic part  76 , a high elastic part  78 , an inclined surface  80  and a flat surface  82 . The flat surface  82  is continuously connected to the inclined surface  80  and is located to the inside of the inclined surface  80 . The low elastic part  76  is located to the upper side of the inclined surface  80 . The low elastic part  76  is located to the inside of the inclined surface  80 . The high elastic part  78  is located to the lower side of the inclined surface  80 . The high elastic part  78  is located to the outside of the inclined surface  80 . The low elastic part  76  is on the flat surface  82 . The high elastic part  78  is under the flat surface  82 . An inner high elastic part  84  is located to the inside of the low elastic part  76 . 
     Also in this midsole  74 , a foot is inclined due to a difference of compression deformation between the low elastic part  76  and the high elastic part  78 . Through this inclination, a golf player can transfer sufficient force to the ground. Also in this midsole  74 , compression deformation changes continuously from the inside to the outside along the inclined surface  80 . The continuous change contributes to stability of swing. Also in this midsole  74 , the inner high elastic part  84  does not absorb much of the force transferred from a foot to the ground. 
     In this midsole  74 , the low elastic part  76  is not exposed on the bottom surface. In other words, the boundary between the low elastic part  76  and the high elastic part  78  does not exist on the bottom surface. This midsole is superior in durability. From the standpoint of durability, the ratio of the thickness t of the low elastic part  76  to the thickness T of the midsole  74  is preferably less than 100%, more preferably 98% or less and particularly preferably 95% or less. From the viewpoint that the top surface of the insole is sufficiently inclined, this ratio is preferably 30% or more, more preferably 50% or more and particularly preferably 80% or more. 
       FIG. 11  shows a cross-sectional view showing a midsole  86  of a golf shoe according to a further embodiment of the present invention. The planar shape of this midsole  86  is equal to that of the midsole  10  shown in  FIG. 2 .  FIG. 11  shows a cross-sectional surface along the lateral line B. In  FIG. 11 , the left side direction indicates an inside direction and the right side direction indicates an outside direction. This midsole  86  has a low elastic part  88 , a high elastic part  90 , a first flat surface  92 , an inclined surface  94  and a second flat surface  96 . The first flat surface  92  is continuously connected to the inclined surface  94  and is located to the inside of the inclined surface  94 . The second flat surface  96  is continuously connected to the inclined surface  94  and is located to the outside of the inclined surface  94 . The low elastic part  88  is located to the upper side of the inclined surface  94 . The low elastic part  88  is located to the inside of the inclined surface  94 . The high elastic part  90  is located to the lower side of the inclined surface  94 . The high elastic part  90  is located to the outside of the inclined surface  94 . The low elastic part  88  is on the first flat surface  92 . The high elastic part  90  is under the first flat surface  92 . The low elastic part  88  is on the second flat surface  96 . The high elastic part  90  is under the second flat surface  96 . An inner high elastic part  98  is located to the inside of the low elastic part  88 . 
     Also in this midsole  86 , a foot is inclined due to a difference of compression deformation between the low elastic part  88  and the high elastic part  90 . Through this inclination, a golf player can transfer sufficient force to the ground. Also in this midsole  86 , compression deformation changes continuously from the inside to the outside along the inclined surface  94 . The continuous change contributes to stability of swing. Also in this midsole  86 , the inner high elastic part  90  does not absorb much of the force transferred from a foot to the ground. 
     In this midsole  86 , the low elastic part  88  is not exposed on the bottom surface. In other words, the boundary between the low elastic part  88  and the high elastic part  90  does not exist on the bottom surface. This midsole is superior in durability. From the standpoint of durability, the ratio of the thickness t of the low elastic part  88  to the thickness T of the midsole  86  is preferably less than 100%, more preferably 98% or less and particularly preferably 95% or less. From the viewpoint that the top surface of the insole is sufficiently inclined, this ratio is preferably 30% or more, more preferably 50% or more and particularly preferably 80% or more. 
       FIG. 12  is a plan view showing a midsole  100  of a golf shoe of a further embodiment of the present invention.  FIG. 12  shows a longitudinal line A and a lateral line B. This midsole  100  has a base  102  and a side wall  104  located on the outer edge of this base  102 . This midsole  100  is designed for a right foot. A midsole for a left foot has a mirror-reversed shape of the shape shown in  FIG. 12 . 
     The cross-sectional shape along the lateral line B of this midsole  100  is equal to that of the midsole  10  shown in  FIG. 4 . This midsole  100  has a low elastic part  106  and a high elastic part  108 . The boundary between the low elastic part  106  and the high elastic part  108  includes an inclined surface. Also in this midsole  100 , a foot is inclined due to a difference of compression deformation between the low elastic part  106  and the high elastic part  108 . Through this inclination, a golf player can transfer sufficient force to the ground. Also in this midsole  100 , compression deformation changes continuously from the inside to the outside along the inclined surface. The continuous change contributes to stability of swing. Also in this midsole  100 , an inner high elastic part  110  does not absorb much of the force transferred from a foot to the ground. 
     As  FIG. 12  clearly shows, the planar shape of the low elastic part  106  is octagonal. In the midsole  100  which has the octagonal low elastic part  106 , compression deformation does not change rapidly in back and forth directions. The octagonal low elastic part  106  contributes to stability of swing. A low elastic part whose planar shape is hexagonal, heptagonal, enneagonal or decagonal also contributes to stability of swing. 
       FIG. 13  is a plan view showing a midsole  112  of a golf shoe of a further embodiment of the present invention.  FIG. 13  shows a longitudinal line A and a lateral line B. This midsole  112  has a base  114  and a side wall  116  located on the outer edge of this base  114 . This midsole  112  is designed for a right foot. A midsole for a left foot has a mirror-reversed shape of the shape shown in  FIG. 13 . 
     The cross-sectional shape along the lateral line B of this midsole  112  is equal to that of the midsole  10  shown in  FIG. 4 . This midsole  112  has a low elastic part  118  and a high elastic part  120 . The boundary between the low elastic part  118  and the high elastic part  120  includes an inclined surface. The planar shape of the low elastic part  118  is an almost semi-ellipse. Also in this midsole  112 , a foot is inclined due to a difference of compression deformation between the low elastic part  118  and the high elastic part  120 . Through this inclination, a golf player can transfer sufficient force to the ground. Also in this midsole  112 , compression deformation changes continuously from the inside to the outside along the inclined surface. The continuous change contributes to stability of swing. Also in this midsole  112 , the inner high elastic part  122  does not absorb much of the force transferred from a foot to the ground. 
       FIG. 14  is a plan view showing a midsole  124  of a golf shoe of a further embodiment of the present invention.  FIG. 14  shows a longitudinal line A and a lateral line B. This midsole  124  has a base  126  and a side wall  128  located on the outer edge of this base  126 . This midsole  124  is designed for a right foot. A midsole for a left foot has a mirror-reversed shape of the shape shown in  FIG. 14 . 
     The cross-sectional shape along the lateral line B of this midsole  124  is equal to that of the midsole  10  shown in  FIG. 4 . This midsole  124  has a low elastic part  130  and a high elastic part  132 . The boundary between the low elastic part  130  and the high elastic part  132  includes an inclined surface. The planar shape of the low elastic part  130  is oblong. Also in this midsole  124 , a foot is inclined due to a difference of compression deformation between the low elastic part  130  and the high elastic part  132 . Through this inclination, a golf player can transfer sufficient force to the ground. Also in this midsole  124 , compression deformation changes continuously from the inside to the outside along the inclined surface. The continuous change contributes to stability of swing. Also in this midsole  124 , an inner high elastic part  134  does not absorb much of the force transferred from a foot to the ground. 
     EXAMPLES 
     Example 1 
     A midsole which has a cross-sectional shape shown in  FIG. 8  was made. In this midsole, the length L is 290 mm, the width W is 100 mm and the thickness T is 6 mm. This midsole has a low elastic part and a high elastic part. The boundary between the low elastic part and the high elastic part includes an inclined surface. A width Wa of the inclined surface is 50 mm. The high elastic part includes an inner high elastic part. A width Wb of the inner high elastic part is 15 mm. In this midsole, the ratio of the thickness t to the thickness T is 100%. By providing this midsole with an outsole, an insole and an upper, a golf shoe according to Example 1 was obtained. 
     Examples 5 and 6 
     By performing the same procedures as those of Example 1 except for designing the ratio of the thickness t to the thickness T as shown in the following Table 1, a golf shoe according to Examples 5 and 6 was obtained. 
     Examples 4 and 7 
     By performing the same procedures as those of Example 1 except for designing the width Wb of the inner high elastic part as shown in the following Table 1, a golf shoe according to Examples 4 and 7 was obtained. A cross-sectional view of the midsole-according to Example 7 is equal to  FIG. 4 . 
     Examples 2, 3 and 8 
     By performing the same procedures as those of Example 1 except for designing the width Wa of the inclined surface as shown in the following Table 1, a golf shoe according to Examples 2, 3 and 8 was obtained. A cross-sectional view of the midsole according to Example 8 is equal to  FIG. 4 . 
     Examples 9 and 10 
     By performing the same procedures as those of Example 1 except for changing the materials for the low elastic part and the high elastic part, a golf shoe according to Examples 9 and 10 was obtained. The hardnesses for the low elastic part and the high elastic part are shown in the following Table 1. 
     Example 11 
     By performing the same procedures as those of Example 1 except for designing a cross-sectional shape of the midsole as shown in  FIG. 15 , a golf shoe according to Example 11 was obtained. This midsole has a low elastic part  136  and a high elastic part  138 . The boundary between the low elastic part  136  and the high elastic part  138  is perpendicularly extended. The high elastic part  138  includes an inner high elastic part  140 . 
     Comparative Example 
     By performing the same procedures as those of Example 1 except for designing a cross-sectional shape of the midsole as shown in  FIG. 16 , a golf shoe according to Comparative Example was obtained. This midsole consists of only a high elastic part. 
     [Impact Test] 
     A golf player wearing the golf shoes hit a gold ball 10 times with a driver. A head speed, flight distance, variation in flight distance, variation in face angle and variation in flight direction were measured. These results are shown in the following Table 1. In this Table 1, the value of the head speed and flight distance is an average value. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Evaluation results 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 Ex- 
                 Ex- 
                 Ex- 
                 Ex- 
                 Ex- 
                 Ex- 
                 Ex- 
                 Ex- 
                 Ex- 
                   
                   
                   
               
               
                   
                 ample 
                 ample 
                 ample 
                 ample 
                 ample 
                 ample 
                 ample 
                 ample 
                 ample 
                 Example 
                 Example 
                 Compa. 
               
               
                   
                 2 
                 3 
                 4 
                 5 
                 6 
                 1 
                 7 
                 8 
                 9 
                 10 
                 11 
                 Example 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 Lateral cross-section 
                 FIG. 8 
                 FIG. 8 
                 FIG. 8 
                 FIG. 10 
                 FIG. 10 
                 FIG. 8 
                 FIG. 4 
                 FIG. 4 
                 FIG. 8 
                 FIG. 8 
                 FIG. 15 
                 FIG. 16 
               
               
                 Width Wa (mm) 
                 5 
                 30 
                 50 
                 30 
                 50 
                 50 
                 50 
                 70 
                 50 
                 50 
                 0 
                 — 
               
               
                 Width Wb (mm) 
                 15 
                 15 
                 5 
                 15 
                 15 
                 15 
                 25 
                 15 
                 15 
                 15 
                 15 
                 — 
               
               
                 Width Wc (mm) 
                 25 
                 25 
                 15 
                 25 
                 25 
                 25 
                 35 
                 25 
                 25 
                 25 
                 25 
                 — 
               
               
                 (t/T) * 100 (%) 
                 100 
                 100 
                 100 
                 40 
                 80 
                 100 
                 100 
                 100 
                 100 
                 100 
                 100 
                 — 
               
               
                 Angle θ (degree) 
                 50 
                 11 
                 7 
                 5 
                 6 
                 7 
                 7 
                 5 
                 7 
                 7 
                 90 
                 — 
               
               
                 Hardness HL (Asker C) 
                 40 
                 40 
                 40 
                 40 
                 40 
                 40 
                 40 
                 40 
                 30 
                 56 
                 40 
                 — 
               
               
                 Hardness HH (Asker C) 
                 60 
                 60 
                 60 
                 60 
                 60 
                 60 
                 60 
                 60 
                 75 
                 70 
                 60 
                 60 
               
               
                 HL/HH 
                 0.67 
                 0.67 
                 0.67 
                 0.67 
                 0.67 
                 0.67 
                 0.67 
                 0.67 
                 0.40 
                 0.80 
                 0.67 
                 — 
               
               
                 Head speed (m/s) 
                 40.9 
                 41.1 
                 41.2 
                 41.0 
                 41.1 
                 41.2 
                 41.1 
                 41.3 
                 41.3 
                 41.0 
                 40.9 
                 40.2 
               
               
                 Flight distance (m) 
                 208 
                 212 
                 216 
                 210 
                 213 
                 214 
                 211 
                 216 
                 213 
                 212 
                 208 
                 201 
               
               
                 Variation of flight 
                 27 
                 26 
                 24 
                 23 
                 22 
                 21 
                 25 
                 20 
                 23 
                 22 
                 29 
                 26 
               
               
                 distance (m) 
               
               
                 Variation of face 
                 5 
                 4 
                 5 
                 4 
                 4 
                 3 
                 4 
                 3 
                 5 
                 4 
                 7 
                 6 
               
               
                 angle (degree) 
               
               
                 Variation of flight 
                 34 
                 29 
                 32 
                 27 
                 25 
                 23 
                 26 
                 22 
                 28 
                 27 
                 40 
                 39 
               
               
                 direction (m) 
               
               
                   
               
            
           
         
       
     
     As table 1 clearly shows, a high head speed and a large flight distance can be obtained by using the golf shoe according to Examples. Particularly, the golf shoe according to Example 1 to Example 10 contributes to flight distance and stability of flight direction. These evaluation results clearly show the advantage of this invention. 
     A shoe which enables a foot to be inclined is also suitable for various sports. The above-mentioned explanations are only illustrative and various arrangements within the scope of the present invention can be made.