A cross-sectional shape of each of dimples 8 of a golf ball 2 is a wave-like curve. The wave-like curve has two first curves 14 , two second curves 16 , two third curves 18 , and one fourth curve 20 . Each first curve 14 and each third curve 18 are upwardly convex. Each second curve 16 and the fourth curve 20 are downwardly convex. Each first curve 14 is connoted to a land 10 at an edge Ed. Each second curve 16 is connected to the first curve 14 at a first inflexion point 22 . Each third curve 18 is connected to the second curve 16 at a second inflexion point 24 . The fourth curve 20 is connected to the third curves 18 at third inflexion points 26 . In the wave-like curve, the upwardly convex curves 14 and 18 and the downwardly convex curves 16 and 20 are alternately arranged.
1. A golf ball having a large number of dimples on a surface thereof, wherein
each dimple has a curved surface,
a cross-sectional shape of the curved surface is a wave-like curve in which a plurality of upwardly convex portions and a plurality of downwardly convex portions are alternately arranged,
the dimple is formed by rotating the wave-like curve around a straight line, and the wave-like curve is symmetrical about the straight line, and
the wave-like curve is obtained by a sine curve and a circular arc being combined with each other.
2. The golf ball according to claim 1 , wherein the number of cycles of the wave-like curve is equal to or greater than 1.5 but equal to or less than 5.5.
3. A golf ball having a large number of dimples on a surface thereof, wherein
each dimple has a curved surface,
a cross-sectional shape of the curved surface is a wave-like curve in which a plurality of upwardly convex portions and a plurality of downwardly convex portions are alternately arranged,
the dimple is formed by rotating the wave-like curve around a straight line, and the wave-like curve is symmetrical about the straight line, and
the wave-like curve is obtained by a cosine curve and a circular arc being combined with each other.
4. The golf ball according to claim 3 , wherein the number of cycles of the wave-like curve is equal to or greater than 2.0 but equal to or less than 6.0.