Golf ball

Abstract

L1 represents a ratio of a lift coefficient relative to a drag coefficient, the lift coefficient and the drag coefficient being measured under conditions of a Reynolds number of 1.290×105 and a spin rate of 2820 rpm. L2 represents a ratio of a lift coefficient relative to a drag coefficient, the lift coefficient and the drag coefficient being measured under conditions of a Reynolds number of 1.771×105 and a spin rate of 2940 rpm.

1 . (canceled) 
     
     
         2 . A golf ball comprising:
 a core including a center and a mid layer positioned outside the center; and   a cover positioned outside the core; and   a plurality of dimples disposed on an outer surface of the cover, wherein   the center has an amount of compressive deformation of equal to or greater than 3.5 mm but equal to or less than 6.0 mm,   the center has a surface hardness of equal to or greater than 45 but equal to or less than 60 in Shore D hardness,   the mid layer has a thickness of equal to or greater than 1.0 mm but equal to or less than 1.8 mm,   the mid layer has a Shore D hardness of equal to or greater than 55 but equal to or less than 70, and   the core has an amount of compressive deformation of equal to or greater than 3.0 mm but equal to or less than 5.0 mm.   
     
     
         3 . The golf ball according to  claim 1 , wherein
 the cover has a Shore D hardness of equal to or greater than 30 but equal to or less than 50, and   the cover has a thickness of equal to or greater than 0.5 mm but equal to or less than 1.8 mm.   
     
     
         4 . The golf ball according to  claim 1 , wherein
 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≤(( L 1+ L 2)/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. 
     
     
         5 . The golf ball according to  claim 1 , wherein
 the center is a rubber composition including a base rubber and a co-crosslinking agent, and   the co-crosslinking agent is equal to or greater than 15 parts by weight of a base rubber of the rubber composition but equal to or less than 50 parts by weight of the base rubber.   
     
     
         6 . The golf ball according to  claim 5 , wherein
 the base rubber includes polybutadiene, and   the polybutadiene is equal to or greater than 50 percent by weight of the base rubber.   
     
     
         7 . The golf ball according to  claim 5 , wherein
 the base rubber includes an organic sulfur compound, and   the organic sulfur compound is equal to or greater than 0.1 parts by weight of the base rubber but less than or equal to 1.5 parts by weight of the base rubber.   
     
     
         8 . The golf ball according to  claim 5 , wherein
 the mid layer includes a thermoplastic resin composition,   the thermoplastic resin composition includes an ionomer resin, and   the ionomer resin is equal to or greater than 50 percent by weight of a base polymer of the thermoplastic resin composition.   
     
     
         9 . The golf ball according to  claim 1 , wherein a total volume of the plurality of dimples is equal to or greater than 430 mm 3  but equal to or less than 580 mm 3 . 
     
     
         10 . The golf ball according to  claim 4 , wherein the ratio L1 is equal to or greater than 0.85 but equal to or less than 0.93. 
     
     
         11 . The golf ball according to  claim 4 , wherein the ratio L2 is equal to or greater than 0.76 but equal to or less than 0.92. 
     
     
         12 . The golf ball according to  claim 1 , wherein a ratio of a sum of spherical surface areas of the plurality of 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. 
     
     
         13 . The golf ball according to  claim 1 , wherein a total number of the plurality of dimples is equal to or greater than 250 but equal to or less than 450. 
     
     
         14 . The golf ball according to  claim 1 , wherein each dimple of the plurality of dimples has a diameter D m  of equal to or greater than 2.0 mm but equal to or less than 6.0 mm. 
     
     
         15 . The golf ball according to  claim 1 , wherein each dimple of the plurality of dimples has a depth of equal to or greater than 0.10 mm but equal to or less than 0.60 mm.