Shoe sole suitable for suppressing pronation
Three or more holes are formed in a lower portion of a first area D 1 in a midsole body 29 separated from one another in a front-rear direction Y, each hole opened in a downward direction and having an inner peripheral surface about an axial line extending in an up-down direction; embedded portions each have an outer peripheral surface about the axial line, and are embedded in the midsole body 29 while being fitted into the holes; the embedded portions are formed by a hard member 4 made of a resin harder than midsole bodies 20 and 29 and outsoles 5 and 5 A; and the hard member 4 includes a connecting portion for connecting together the embedded portions in the front-rear direction Y on the lower surface of the midsole body 29.
1. A shoe sole suitable for suppressing pronation, wherein:
the shoe sole includes a front foot portion, a middle foot portion and a rear foot portion continuous with one another in a front-rear direction of a foot, the shoe sole comprising:
a midsole having an upper surface and a lower surface and absorbing an impact of landing; and
an outsole having a bonded surface to be bonded to the lower surface of the midsole, and a ground contact surface to be in contact with a road surface;
the midsole includes a midsole body formed by a foamed resin;
the midsole body is provided in a first area including a medial side of the middle foot portion and/or a medial side of the rear foot portion, and in a second area including the front foot portion, the middle foot portion and the rear foot portion excluding the first area;
the midsole body has three or more holes in a lower portion of the first area, the holes being separated from one another in the front-rear direction, the holes each opening in a downward direction and having an inner peripheral surface about an axial line extending in an up-down direction;
three or more embedded portions are provided;
the embedded portions each have an outer peripheral surface about the axial line, and are embedded in the midsole body while being fitted into the holes;
the embedded portions each are formed by a hard member made of a resin harder than the midsole body and the outsole; and
the hard member includes a connecting portion for connecting together the embedded portions in the front-rear direction on the lower surface of the midsole body.
2. A shoe sole according to claim 1 , wherein a first hole having a largest cross-sectional area along a cross section perpendicular to the axial line among the holes is placed in a middle portion of the first area in the front-rear direction.
3. A shoe sole according to claim 1 , wherein a first embedded portion having a largest height among the embedded portions is placed in a middle portion of the first area in the front-rear direction.
4. A shoe sole according to claim 1 , wherein:
a first embedded portion having a largest height among the embedded portions is placed on a medial side of a front portion of a calcaneal bone or at a position more medial than the front portion of the calcaneal bone;
the embedded portions other than the first embedded portion have gradually smaller heights in a rearward direction past the first embedded portion; and
the embedded portions other than the first embedded portion have gradually smaller heights in a forward direction past the first embedded portion.
5. A shoe sole according to claim 1 , wherein:
a distance from the bonded surface of the outsole to the upper surface of the midsole increases toward an edge of the medial side of the middle foot portion and an edge of the medial side of the rear foot portion;
the edge on the medial side includes a narrowed portion in the middle foot portion;
five or more embedded portions are provided from the middle foot portion to the rear foot portion; and
the embedded portions are placed on a virtual curved line which is shaped along the edge of the middle foot portion and the edge of the rear foot portion and along the narrowed portion.
6. A shoe sole according to claim 5 , wherein the embedded portions each have a top surface, and the top surface of each of the embedded portions is inclined so as to extend diagonally upward toward the medial edge.
7. A shoe sole according to claim 1 , wherein:
a distance from the bonded surface of the outsole to the upper surface of the midsole increases toward an edge of the medial side of the middle foot portion and an edge of the medial side of the rear foot portion; and
the embedded portions each have a top surface, and the top surface of each of the embedded portions is inclined so as to extend diagonally upward toward the edges.
8. A shoe sole according to claim 7 , wherein:
the midsole body is further provided in an upper portion of the first area which is upward of the lower portion of the first area; and
the top surface is inclined along an upper surface of the midsole body above each of the embedded portions whose top surface is inclined.
9. A shoe sole according to claim 8 , wherein:
on the medial side of the rear foot portion, an auxiliary embedded portion is provided in a portion closer to a center of a calcaneal bone than the embedded portions provided on the medial edge; and
a height of the auxiliary embedded portion is smaller than that of the embedded portions provided on the medial edge.
10. A shoe sole according to claim 1 , wherein two or more of the embedded portions provided on the medial side of the rear foot portion are placed more medial than a portion of a calcaneal bone excluding a sustentaculum talus of the calcaneal bone.
11. A shoe sole according to claim 1 , wherein an upper surface of the connecting portion is secured to the lower surface of the midsole body.
12. A shoe sole according to claim 11 , wherein:
the outer peripheral surface of each of the embedded portions is secured to the midsole body on the inner peripheral surface of each of the holes, thereby suppressing compressive deformation in an up-down direction of the lower portion of the first area around the holes; and
the lower portion of the first area thereby less easily undergoes compressive deformation than the midsole body in an upper portion of the first area and in the second area.
13. A shoe sole according to claim 1 , wherein:
the midsole includes a plate made of a non-foamed resin covering over the embedded portions in the first area; and
the midsole body includes a lower midsole body bonded to a lower surface of the plate, and an upper midsole body bonded to an upper surface of the plate.
14. A shoe sole according to claim 13 , wherein each of the holes runs in an up-down direction through the lower midsole body.
15. A shoe sole according to claim 1 , wherein:
a color of the midsole body is different from a color of the hard member; and
the outsole placed in the first area includes a see-through portion formed by a semitransparent rubber, and the hard member is viewable through the see-through portion from below the outsole.
16. A shoe sole according to claim 15 , wherein:
the outsole is made up of a plurality of parts, and a part placed in the first area includes a frame portion provided in a loop shape along a periphery of the see-through portion, and the see-through portion formed integrally with the frame portion; and
the frame portion is formed by a black rubber in which carbon black is used as a reinforcing filler.
17. A shoe sole according to claim 1 , wherein a JIS-C hardness of a material of the midsole body is set to a value in the range of 45° to 65°, and a JIS-A hardness of the hard member is set to a value in the range of 55° to 95°.