Golf ball

Abstract

A golf ball 14 has a northern hemisphere N above an equatorial line Eq and a southern hemisphere S below the equatorial line Eq. Each of the northern hemisphere N and the southern hemisphere S has a pole vicinity region 30, an equator vicinity region 32, and a mid region 34. Each of the pole vicinity region 30, the equator vicinity region 32, and the mid region 34 has numerous dimples 20. The dimple pattern of the pole vicinity region 30 includes four units that are rotationally symmetrical to each other about a pole P. The dimple pattern of the equator vicinity region 32 includes six units that are rotationally symmetrical to each other about the pole P. The dimples 20 included in the mid region 34 are arranged along a mid latitude line 28. The number of the dimples 20 included in the mid region 34 is 24.

1 . A golf ball having, in a surface thereof, a northern hemisphere and a southern hemisphere each of which has a pole vicinity region, an equator vicinity region, and a mid region located between the pole vicinity region and the equator vicinity region, wherein
 each of the pole vicinity region, the equator vicinity region, and the mid region has a large number of dimples,   a dimple pattern of the pole vicinity region includes a plurality of units that are rotationally symmetrical to each other about a pole,   a dimple pattern of the equator vicinity region includes a plurality of units that are rotationally symmetrical to each other about the pole,   the number Np of the units of the pole vicinity region is different from the number Ne of the units of the equator vicinity region, and   the dimples included in the mid region are arranged substantially along a latitude line.   
     
     
         2 . The golf ball according to  claim 1 , wherein the latitude line has a latitude of 20° or greater and 40° or less. 
     
     
         3 . The golf ball according to  claim 2 , wherein the latitude of the latitude line is substantially 30°. 
     
     
         4 . The golf ball according to  claim 1 , wherein
 the number Np is equal to or greater than 3 and equal to or less than 6, and   the number Ne is equal to or greater than 3 and equal to or less than 6.   
     
     
         5 . The golf ball according to  claim 1 , wherein the number Nm of the dimples in the mid region is equal to or greater than 18 and equal to or less than 48. 
     
     
         6 . The golf ball according to  claim 1 , wherein the number Nm of the dimples in the mid region is a common multiple of the number Np and the number Ne. 
     
     
         7 . The golf ball according to  claim 1 , wherein
 the dimples included in the mid region have the same diameter, and   these dimples are arranged along the latitude line at regular intervals.   
     
     
         8 . The golf ball according to  claim 7 , wherein a central angle between dimples adjacent to each other is equal to or greater than 7.5° and equal to or less than 20°. 
     
     
         9 . The golf ball according to  claim 1 , wherein the number of dimples that are adjacent to a boundary line between the pole vicinity region and the mid region and included in the pole vicinity region is equal to the number of the dimples that are arranged along the latitude line. 
     
     
         10 . The golf ball according to  claim 1 , wherein the number of dimples that are adjacent to a boundary line between the equator vicinity region and the mid region and included in the equator vicinity region is equal to the number of the dimples that are arranged along the latitude line. 
     
     
         11 . The golf ball according to  claim 1 , wherein a ratio of the number of the dimples that exist in the pole vicinity region to the number of the dimples that exist in each hemisphere is equal to or greater than 20% and equal to or less than 70%. 
     
     
         12 . The golf ball according to  claim 1 , wherein a ratio of the number of the dimples that exist in the equator vicinity region to the number of the dimples that exist in each hemisphere is equal to or greater than 20% and equal to or less than 70%. 
     
     
         13 . The golf ball according to  claim 1 , wherein a dimple pattern of the northern hemisphere is equivalent to a dimple pattern of the southern hemisphere. 
     
     
         14 . The golf ball according to  claim 1 , wherein the total number of the dimples is equal to or greater than 200 and equal to or less than 600. 
     
     
         15 . The golf ball according to  claim 1 , wherein each dimple has a diameter of 2.00 mm or greater and 6.00 mm or less. 
     
     
         16 . The golf ball according to  claim 1 , wherein a ratio of the sum of areas of all the dimples to a surface area of a phantom sphere is equal to or greater than 60% and equal to or less than 88%. 
     
     
         17 . The golf ball according to  claim 1 , wherein the total volume of the dimples is equal to or greater than 250 mm 3  and equal to or less than 400 mm 3 . 
     
     
         18 . The golf ball according to  claim 1 , wherein each dimple has a depth of 0.05 mm or greater and 0.60 mm or less.