Golf ball

Abstract

A golf ball 2 includes a center 8 , a mid layer 10 , a cover 6 and dimples 12 . The cover 6 has a Shore D hardness of 30-50. The golf ball 2 has an amount of compressive deformation of 3.0-5.0 mm. The ball 2 meets a mathematical formula (I): 0.80≦((L1+L2)/2)≦0.95  (I). L1 represents a ratio of a lift coefficient CL1 relative to a drag coefficient CD1, the lift coefficient CL1 and the drag coefficient CD1 being measured under conditions of a Reynolds number of 1.290×10 5 and a spin rate of 2820 rpm. L2 represents a ratio of a lift coefficient CL2 relative to a drag coefficient CD2, the lift coefficient CL2 and the drag coefficient CD2 being measured under conditions of a Reynolds number of 1.771×10 5 and a spin rate of 2940 rpm.

What is claimed is: 
     
         1 . A golf ball comprising a core and a cover positioned outside the core, wherein
 the golf ball has a large number of dimples on a surface thereof,   the cover has a Shore D hardness of equal to or greater than 30 but equal to or less than 50,   the golf ball has an amount of compressive deformation of equal to or greater than 3.0 mm but equal to or less than 5.0 mm, the amount of compressive deformation being measured under conditions of an initial load of 98 N and a final load of 1274 N, and   the golf ball meets the following mathematical formula (I):
   0.80≦((L1+L2)/2)≦0.95  (I),
 
   
       where: L1 represents a ratio (CL1/CD1) of a lift coefficient CL1 relative to a drag coefficient CD1, the lift coefficient CL1 and the drag coefficient CD1 being measured under conditions of a Reynolds number of 1.290×10 5  and a spin rate of 2820 rpm; and L2 represents a ratio (CL2/CD2) of a lift coefficient CL2 relative to a drag coefficient CD2, the lift coefficient CL2 and the drag coefficient CD2 being measured under conditions of a Reynolds number of 1.771×10 5  and a spin rate of 2940 rpm. 
     
     
         2 . The golf ball according to  claim 1 , wherein a total volume of the dimples is equal to or greater than 430 mm 3  but equal to or less than 580 mm 3 . 
     
     
         3 . The golf ball according to  claim 1 , wherein the cover has a thickness of equal to or greater than 0.3 mm but equal to or less than 1.8 mm. 
     
     
         4 . The golf ball according to  claim 1 , wherein the ratio L1 is equal to or greater than 0.85 but equal to or less than 0.93. 
     
     
         5 . The golf ball according to  claim 1 , wherein the ratio L2 is equal to or greater than 0.76 but equal to or less than 0.92. 
     
     
         6 . The golf ball according to  claim 1 , wherein a ratio of a sum of spherical surface areas of the dimples relative to a surface area of a phantom sphere of the golf ball is equal to or greater than 0.780 but equal to or less than 0.950. 
     
     
         7 . The golf ball according to  claim 1 , wherein a total number of the dimples is equal to or greater than 250 but equal to or less than 450. 
     
     
         8 . The golf ball according to  claim 1 , wherein each dimple has a diameter Dm of equal to or greater than 2.0 mm but equal to or less than 6.0 mm. 
     
     
         9 . The golf ball according to  claim 1 , wherein each dimple has a depth of equal to or greater than 0.10 mm but equal to or less than 0.60 mm.