Sole Structure for a Sports Shoe

Abstract

A sole structure for a sports shoe that controls bendability of a forefoot region of the sole structure. The sole structure includes an upper midsole disposed on an upper side of the forefoot region of the sports shoe and formed of a soft elastic material, a lower midsole disposed under the upper midsole and formed of a soft elastic material, and an outsole that is disposed on a lower surface of the lower midsole and that has sole bent grooves extending substantially in a sole width direction. Both the lower surface of the upper midsole and the upper surface of the lower midsole have corrugated mating surfaces that are formed of wavy shapes extending substantially in a sole longitudinal direction. Ridge lines and trough lines of the wavy shapes of the upper midsole extend substantially in the sole width direction. The ridge lines of the wavy shapes of the upper midsole of a relatively higher hardness are overlapped with the sole bent grooves of the outsole in a vertical direction.

What is claimed is: 
     
         1 . A sole structure for a sports shoe disposed in a forefoot region of said sports shoe comprising:
 an upper midsole that is disposed on an upper side of said forefoot region of said sports shoe and that is formed of a soft elastic material;   a lower midsole that is disposed on a lower side of said forefoot region, that has an upper surface adapted to contact a lower surface of said upper midsole, and that is formed of a soft elastic material; and   an outsole that is disposed on a lower surface of said lower midsole, that has a ground contact surface adapted to contact a ground surface, and that has a sole bent groove extending substantially in a sole width direction,   wherein both said lower surface of said upper midsole and said upper surface of said lower midsole have a corrugated surface that is formed of wavy shapes extending substantially in a sole longitudinal direction, ridge lines and trough lines of said wavy shapes extend substantially in the sole width direction, and said upper midsole and said lower midsole have a hardness difference,   wherein at least a portion of said ridge lines of said wavy shapes of said upper midsole or said lower midsole that has a relatively higher hardness is overlapped with said sole bent groove of said outsole in a vertical direction.   
     
     
         2 . The sole structure according to  claim 1 , wherein said ridge line of said wavy shapes are overlapped with said sole bent groove in the vertical direction either at a medial side part, a lateral side part, or a sole laterally central part of said forefoot region. 
     
     
         3 . The sole structure according to  claim 1 , wherein said bent groove comprises a first sole bent groove and a second sole bent groove that are spaced apart on opposite sides of a metatarsophalangeal joint of a foot of a shoe wearer in the sole longitudinal direction. 
     
     
         4 . The sole structure according to  claim 3 , wherein a third sole bent groove is further disposed between said first sole bent groove and said second sole bent groove and said third sole bent groove is spaced apart from said first sole bent groove and said second sole bent groove in the sole longitudinal direction. 
     
     
         5 . The sole structure according to  claim 1 , wherein said sole bent groove opens at least at either one of a medial side end or a lateral side end of said forefoot region. 
     
     
         6 . The sole structure according to  claim 1 , wherein said sole bent groove closes at both a medial side end and a lateral side end of said forefoot region. 
     
     
         7 . The sole structure according to  claim 1 , wherein said sole bent groove includes a slit that extends through a thickness of said outsole. 
     
     
         8 . The sole structure according to  claim 1 , wherein said sole bent groove includes a recessed groove that is formed on said lower surface of said lower midsole. 
     
     
         9 . The sole structure according to  claim 1 , wherein said ridge lines and trough lines of said wavy shapes extend across an entire width of said forefoot region. 
     
     
         10 . The sole structure according to  claim 1 , wherein said ridge lines and trough lines of said wavy shapes are disposed only at a laterally central side portion of said forefoot region. 
     
     
         11 . A sole structure for a sports shoe disposed in a forefoot region of said sports shoe comprising:
 an upper midsole that is disposed on an upper side of said forefoot region of said sports shoe and that is formed of a soft elastic material;   a lower midsole that is disposed on a lower side of said forefoot region, that has an upper surface adapted to contact a lower surface of said upper midsole, and that is formed of a soft elastic material; and   an outsole that is disposed on a lower surface of said lower midsole, that has a ground contact surface adapted to contact a ground surface, and that has a sole bent groove extending substantially in a sole width direction,   wherein either one of said lower surface of said upper midsole or said upper surface of said lower midsole has a corrugated surface that are formed of wavy shapes extending substantially in a sole longitudinal direction, ridge lines and trough lines of said wavy shapes extend substantially in the sole width direction, and at least a portion of said ridge lines of said wavy shapes is overlapped with said sole bent groove of said outsole in a vertical direction.   
     
     
         12 . The sole structure according to  claim 11 , wherein said ridge line of said wavy shapes are overlapped with said sole bent groove in the vertical direction either at a medial side part, a lateral side part, or a sole laterally central part of said forefoot region. 
     
     
         13 . The sole structure according to  claim 11 , wherein said bent groove comprises a first sole bent groove and a second sole bent groove that are spaced apart on opposite sides of a metatarsophalangeal joint of a foot of a shoe wearer in the sole longitudinal direction. 
     
     
         14 . The sole structure according to  claim 13 , wherein a third sole bent groove is further disposed between said first sole bent groove and said second sole bent groove and said third sole bent groove is spaced apart from said first sole bent groove and said second sole bent groove in the sole longitudinal direction. 
     
     
         15 . The sole structure according to  claim 11 , wherein said sole bent groove opens at least at either one of a medial side end or a lateral side end of said forefoot region. 
     
     
         16 . The sole structure according to  claim 11 , wherein said sole bent groove closes at both a medial side end and a lateral side end of said forefoot region. 
     
     
         17 . The sole structure according to  claim 11 , wherein said sole bent groove includes a slit that extends through a thickness of said outsole. 
     
     
         18 . The sole structure according to  claim 11 , wherein said sole bent groove includes a recessed groove that is formed on said lower surface of said lower midsole. 
     
     
         19 . The sole structure according to  claim 11 , wherein said ridge lines and trough lines of said wavy shapes extend across an entire width of said forefoot region. 
     
     
         20 . The sole structure according to  claim 11 , wherein said ridge lines and trough lines of said wavy shapes are disposed only at a laterally central side portion of said forefoot region. 
     
     
         21 . The sole structure according to  claim 11 , wherein said upper surface of said lower midsole or said lower surface of said upper midsole that does not have said corrugated surface has a planar surface, and wherein there is formed a gap between said planar surface and said lower surface of said upper midsole or said upper surface of said lower midsole.