Golf ball

Abstract

A golf ball has a plurality of dimples, wherein: (1) the dimples have a peripheral edge with a radius of curvature R from 0.5 mm to 2.5 mm; (2) the surface coverage SR of the dimples, expressed as a percentage of the surface area of a hypothetical sphere representing the ball if it had no dimples, is from 60% to 74%; and (3) the ratio ER of a collective number of dimples RA having a radius of curvature R to diameter D ratio (R/D) of at least 20%, divided by a total number of dimples N on the surface of the ball, is from 15% to 95%. This combination of features enables damage to the paint film on the surface of the ball to be minimized, improves the durability of markings on the surface of the ball, and prevents a decline in ball performance.

1 . A golf ball comprising a spherical surface on which a plurality of dimples are formed, wherein the dimples satisfy conditions (1) to (3) below:
 (1) the dimples have a peripheral edge provided with a roundness represented by a radius of curvature R of from 0.5 mm to 2.5 mm;   (2) the surface coverage SR of the dimples, which is the sum of individual dimple surface areas, each defined by a flat plane circumscribed by an edge of the dimple, expressed as a percentage of the surface area of a hypothetical sphere representing the ball were the ball to have no dimples on the surface thereof, is from 60% to 74%; and   (3) the ratio ER of a collective number of dimples RA having a radius of curvature R to diameter D ratio (R/D) of at least 20%, divided by a total number of dimples N on the surface of the ball, is from 15% to 95%.   
     
     
         2 . The golf ball of  claim 1  which further satisfies condition (4) below:
 (4) the ball has thereon a plurality of dimple types of differing diameter, and the ratio DER of a combined number of dimples DE obtained by adding together dimples having an own diameter and an own radius of curvature larger than or equal to a radius of curvature of dimples of larger diameter than said own diameter plus dimples of a type having a largest diameter, divided by the total number of dimples N on the surface of the ball, is at least 80%. 
 
     
     
         3 . The golf ball of  claim 1  which further satisfies condition (5) below:
 (5) the total number of dimples N is not more than 380. 
 
     
     
         4 . The golf ball of  claim 1  which further satisfies condition (6) below:
 (6) each dimple has a spatial volume below a flat plane circumscribed by an edge of the dimple, and the sum of the dimple spatial volumes, expressed as a percentage (VR) of the volume of a hypothetical sphere representing the ball were the ball to have no dimples on the surface thereof, is from 0.8% to 1.7%. 
 
     
     
         5 . The golf ball of  claim 1 , wherein the dimples are spread out over the spherical surface of the ball in a configuration selected from the group consisting of icosahedral configurations, dodecahedral configurations, octahedral configurations, configurations having three-fold symmetry, and configurations having five-fold symmetry.