| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve the direct advancing rolling property by a method wherein on the surface of ground parts which are formed between respectively dimples, very small holes of which the number is larger than that of the dimples, are provided. SOLUTION: For example, on a ground part 2 between dimples 1 of a one- piece ball wherein the number of the dimples 1 is approx. 336, a number, which is not less than the number of the dimples 1, e.g. 432 of very small holes 3 with a diameter of 0.2-1.5mm, and a depth of 30-150μm, are formed. When the carry and total distances of this golf ball, and a golf ball on which the very small holes 3 are not formed, are compared, the ball with the very small holes 3 clearly exceeds the other. Also, an average distance for curving at the time of rolling is smaller for the ball with the very small holes 3. By forming the very small hole 3, a deformation of the ball at the time of impact, and a contact area between the ground part 2 and turf at the time of rolling reduce in response to the diametrical dimension of the very small hole 3. Therefore, the direct advancing rolling property of the ball can be improved.</p> |
