Golf ball

Abstract

A golf ball 2 has a large number of dimples 10 on a surface thereof. Fifteen axes are assumed for a phantom sphere of the golf ball 2 . 30240 points on a predetermined region of the surface of the golf ball 2 during backspin about each axis are determined. A length L 1 of a perpendicular line that extends from each point to the axis is calculated. A total length L 2 is calculated by summing 21 lengths L 1 calculated based on 21 perpendicular lines arranged in a direction of the axis. A transformed data constellation is obtained by performing Fourier transformation on a data constellation of 1440 total lengths L 2 calculated along a direction of rotation about the axis. A peak value and an order of a maximum peak of the transformed data constellation are calculated. A minimum value of 15 peak values is not less than 95 mm.

What is claimed is: 
     
         1 . A golf ball having a plurality of dimples on a surface thereof, wherein
 a minimum value of 15 peak values obtained by executing steps (a) to (h) for each of 15 axes Ax is not less than 95 mm, when spherical polar coordinates of a point that is located on a surface of a phantom sphere of the golf ball and has a latitude of θ (degrees) and a longitude of ϕ (degrees) are represented by (θ, ϕ), the 15 axes Ax being   (1) a first axis Ax1 passing through a point Pn1 coordinates of which are (75, 270) and a point Ps1 coordinates of which are (−75, 90),   (2) a second axis Ax2 passing through a point Pn2 coordinates of which are (60, 270) and a point Ps2 coordinates of which are (−60, 90)   (3) a third axis Ax3 passing through a point Pn3 coordinates of which are (45, 270) and a point Ps3 coordinates of which are (−45, 90),   (4) a fourth axis Ax4 passing through a point Pn4 coordinates of which are (30, 270) and a point Ps4 coordinates of which are (−30, 90),   (5) a fifth axis Ax5 passing through a point Pn5 coordinates of which are (15, 270) and a point Ps5 coordinates of which are (−15, 90),   (6) a sixth axis Ax6 passing through a point Pn6 coordinates of which are (75, 0) and a point Ps6 coordinates of which are (−75, 180),   (7) a seventh axis Ax1 passing through a point Pn7 coordinates of which are (60, 0) and a point Ps7 coordinates of which are (−60, 180),   (8) an eighth axis Ax8 passing through a point Pn8 coordinates of which are (45, 0) and a point Ps8 coordinates of which are (−45, 180),   (9) a ninth axis Ax9 passing through a point Pn9 coordinates of which are (30, 0) and a point Ps9 coordinates of which are (−30, 180),   (10) a tenth axis Ax10 passing through a point Pn10 coordinates of which are (15, 0) and a point Ps10 coordinates of which are (−15, 180),   (11) an eleventh axis Ax11 passing through a point Pn11 coordinates of which are (75, 90) and a point Ps11 coordinates of which are (−75, 270),   (12) a twelfth axis Ax12 passing through a point Pn12 coordinates of which are (60, 90) and a point Ps12 coordinates of which are (−60, 270),   (13) a thirteenth axis Ax13 passing through a point Pn13 coordinates of which are (45, 90) and a point Ps13 coordinates of which are (−45, 270),   (14) a fourteenth axis Ax14 passing through a point Pn14 coordinates of which are (30, 90) and a point Ps14 coordinates of which are (−30, 270), and   (15) a fifteenth axis Ax15 passing through a point Pn15 coordinates of which are (15, 90) and a point Ps15 coordinates of which are (−15, 270), the steps (a) to (h) being the steps of   (a) assuming a great circle that is present on the surface of the phantom sphere and is orthogonal to the axis Ax,   (b) assuming two small circles that are present on the surface of the phantom sphere, that are orthogonal to the axis Ax, and of which absolute values of central angles with the great circle are each 30°,   (c) defining a region, of the surface of the golf ball, which is obtained by dividing the surface of the golf ball at these small circles and which is sandwiched between these small circles,   (d) determining 30240 points, on the region, arranged at intervals of a central angle of 3° in a direction of the axis Ax and at intervals of a central angle of 0.25° in a direction of rotation about the axis Ax,   (e) calculating a length L 1  of a perpendicular line that extends from each point to the axis Ax,   (f) calculating a total length L 2  by summing 21 lengths L 1  calculated on the basis of 21 perpendicular lines arranged in the direction of the axis Ax,   (g) obtaining a transformed data constellation by performing Fourier transformation on a data constellation of 1440 total lengths L 2  calculated along the direction of rotation about the axis Ax, and   (h) calculating a peak value and an order of a maximum peak of the transformed data constellation,   a minimum value of 15 orders obtained by executing the steps (a) to (h) is not less than 27,   a maximum value of the 15 orders obtained by executing the steps (a) to (h) is not greater than 37, and   an average of the 15 orders obtained by executing the steps (a) to (h) is not less than 30 and not greater than 34.   
     
     
         2 . The golf ball according to  claim 1 , wherein an average of the 15 peak values obtained by executing the steps (a) to (h) is not less than 200 mm. 
     
     
         3 . The golf ball according to  claim 1 , wherein a total volume of the dimples is not less than 450 mm 3  and not greater than 750 mm 3 .