Golf ball

Abstract

A golf ball of the present invention includes a core and a cover located outside the core and having a plurality of dimples on a surface thereof. A bottom of each of the dimples has a curved shape protruding toward an outside of the golf ball, and the protruding portion has a spherical crown shape having a radius of curvature R of 20 to 50 mm. A depth d of a center protruding portion of the bottom of the dimple is a perpendicular distance between a line S connecting both ends of an outer periphery of the dimple and a highest point of the protruding portion. A volume occupation ratio VR of the dimple is less than 0.75. A relationship between Shore D hardness H of a material of the cover and the depth d (unit: mm) satisfies the following Formula 1: ( H −78)/(−300)> d   (Formula 1).

What is claimed is: 
     
         1 . A golf ball comprising a core, and a cover located outside the core and having a plurality of dimples on a surface thereof, wherein
 a bottom of each of the dimples has a protruding portion having a curved shape protruding toward an outside of the golf ball;   the protruding portion has a spherical crown shape having a radius of curvature R of 20 to 50 mm;   a depth d of the protruding portion of the bottom of the dimple is a perpendicular distance between a line S connecting both ends of an outer periphery of the dimple and a highest point of the protruding portion;   a volume occupation ratio VR of the dimple is less than 0.75; and   a relationship between Shore D hardness H of a material of the cover and the depth d (unit: mm) satisfies the following Formula 1:
   ( H −78)/(−300)> d   (Formula 1).
 
   
     
     
         2 . The golf ball according to  claim 1 , wherein the Shore D hardness of the material of the cover is 50 to 60. 
     
     
         3 . The golf ball according to  claim 1 , further comprising an intermediate layer between the core and the cover, wherein Shore D hardness of a material of the intermediate layer is 55 or more. 
     
     
         4 . The golf ball according to  claim 3 , wherein the Shore D hardness of the material of the intermediate layer is higher than the Shore D hardness of the material of the cover. 
     
     
         5 . The golf ball according to  claim 1 , further comprising a coating layer located outside the cover, wherein:
 the coating layer contains delustering particles;   average roughness Ra of a surface of the coating layer is 0.5 to 1.0; and   the volume occupation ratio VR of the dimple is less than 0.70.   
     
     
         6 . The golf ball according to  claim 1 , wherein the number of dimples having the protruding portion having the spherical crown shape having the radius of curvature R of 20 to 50 mm is 50% or more of the total number of dimples on a surface of the cover. 
     
     
         7 . The golf ball according to  claim 1 , wherein in addition to the dimples having the protruding portion having the spherical crown shape having the radius of curvature R of 20 to 50 mm, dimples having a protruding portion having a spherical crown shape having a radius of curvature R of 12 mm or less are arranged, and the number of the dimples having the protruding portion having the spherical crown shape having the radius of curvature R of 12 mm or less is 1 to 10% of the total number of dimples on a surface of the cover.