| 摘要 |
<p>In a golf ball whose outer layer cover is harder than the inner layer cover, convex ribs are formed on the inner surface of the outer layer cover such that the convex ribs intrude into the inner layer cover. When the apexes of each spherical triangle of a hypothetical octahedron or icosahedron assumed on the inner surface of the outer layer cover are each represented by A, the center of the triangle is represented by B, the midpoint of each side of the triangle is represented by C, and a point on a line connecting the center B and each apex A is represented by D, a convex rib is arranged along each of a line between point A and point D, a line between point B and point D, and a line between point C and point D.</p> |
