Golf ball

Abstract

A golf ball 2 includes a core 4 , a mid layer 6 , and a cover 8 . A difference DH in hardness between a surface and a central point of the core 4 , a thickness Tm and a hardness Hm of the mid layer 6 , a thickness Tc and a hardness Hc of the cover 8 , and an amount of compressive deformation Sb of the golf ball 2 meet the following mathematical formulas. ( DH*Hm )/( Hc*c )>80 (( Sb*c )/( Hc*Hm*Tm ))*1000>0.75 The golf ball 2 further includes a plurality of small dimples each having an area of less than 8.0 mm 2 and a plurality of large dimples each having an area of equal to or greater than 8.0 mm 2 .

What is claimed is: 
     
         1 . A golf ball comprising a core, a mid layer positioned outside the core, and a cover positioned outside the mid layer, wherein
 the golf ball has a plurality of dimples on a surface thereof,   the dimples include a plurality of small dimples each having an area of less than 8.0 mm 2  and a plurality of large dimples each having an area of equal to or greater than 8.0 mm 2 ,   a ratio PS of a sum of the areas of the small dimples relative to a surface area of a phantom sphere of the golf ball is less than 2.0%,   a ratio PL of a sum of the areas of the large dimples relative to the surface area of the phantom sphere is equal to or greater than 79.0%, and   a degree of uniformity G of the areas (mm 2 ) of the large dimples is equal to or less than 1.15.   
     
     
         2 . The golf ball according to  claim 1 , wherein a difference DH in Shore C hardness between a surface and a central point of the core, a Shore D hardness Hm of the mid layer, and a thickness Tc (mm) and a Shore D hardness Hc of the cover meet the following mathematical formula (1):
   ( DH*Hm )/( Hc*Tc )>80   (1).
   
     
     
         3 . The golf ball according to  claim 1 , wherein a thickness Tm (mm) and a Shore D hardness Hm of the mid layer, a thickness Tc (mm) and a Shore D hardness Hc of the cover, and an amount of compressive deformation Sb (mm) of the golf ball meet the following mathematical formula (2):
   (( Sb*Tc )/( Hc*Hm*Tm ))*1000>0.75   (2).
   
     
     
         4 . The golf ball according to  claim 1 , wherein a shore D hardness Hc of the cover is equal to or less than 40. 
     
     
         5 . The golf ball according to  claim 1 , wherein a shore D hardness Hm of the mid layer is equal to or greater than 55. 
     
     
         6 . The golf ball according to  claim 1 , wherein the ratio PS is equal to or greater than 0.7%. 
     
     
         7 . The golf ball according to  claim 1 , wherein a number NS of the small dimples is equal to or greater than 6 but equal to or less than 20. 
     
     
         8 . The golf ball according to  claim 1 , wherein a ratio (NS/N) of a number NS of the small dimples relative to a total number N of the dimples is equal to or greater than 0.01 but equal to or less than 0.07. 
     
     
         9 . The golf ball according to  claim 1 , wherein a depth of a deepest part of each dimple from a surface of the phantom sphere is equal to or greater than 0.10 mm but equal to or less than 0.65 mm. 
     
     
         10 . The golf ball according to  claim 1 , wherein a total volume of the dimples is equal to or greater than 450 mm 3  but equal to or less than 750 mm 3 . 
     
     
         11 . The golf ball according to  claim 1 , wherein the ratio PL is equal to or greater than 79.5%, and the degree of uniformity G is equal to or less than 1.10. 
     
     
         12 . The golf ball according to  claim 8 , wherein the ratio PL is equal to or greater than 80.0%, and the degree of uniformity G is equal to or less than 1.05.