A golf ball having a cover with a plurality of dimples on the surface thereof is provided with a coat of mutually differing properties on dimple areas of the surface and on land areas between the dimples. The dimple areas are formed with a coat having a low coefficient of friction, do not affect the spin performance when the ball is struck and are not prone to staining. The land areas are formed with a coat having a high coefficient of friction, enabling a lower spin rate to be achieved and thus increasing the distance traveled by the ball, particularly when struck with a middle iron, and also help impart a high spin rate and a good controllability on approach shots.

Provided is a spherical polyhedron division structure of a golf ball where dimples are arranged to have a well-defined symmetry and a dimple pattern. In the spherical polyhedron division structure, wherein an arbitrary point on a surface of a spherical body constituting a golf ball is defined as a pole, a great circle dividing the spherical body into a northern hemisphere and a southern hemisphere with respect to the pole as a reference point is defined as an equator, the surface of the spherical body is divided into six areas formed by segments connecting the pole and points obtained by dividing the equator in units of 60°, each area is divided into spherical polygons formed by four spherical rectangles and two spherical triangles having sides with different lengths, and the spherical polygons arranged in different adjacent areas are symmetric with each other.

A golf ball dimple pattern based on a square dipyramid, i.e., two square pyramids connected base-to-base, is disclosed. The dimples are arranged within four substantially identical triangular sections on each of two substantially identical hemispheres of the ball.

The present invention provides a golf ball wherein each hemisphere has a dimple pattern based on a pyramid having dissimilar sides. The resulting overall dimple pattern is not based on preexisting polyhedral, and is not attainable using conventional dimple packing methods.

A golf ball wherein a slide amount Ds is 1.05 mm or less and a post-slide contact time Tc is 600 μs or more in the case where a golf ball 140 is dropped freely from a height position of 3 m above and away from a collision surface 130a inclined 58 degrees with respect to a horizontal direction to collide with the collision surface, the slide amount Ds being a vertical displacement of the golf ball from when the golf ball starts sliding on the collision surface to when the golf ball stops sliding on the collision surface, and the post-slide contact time Tc being a period from when the golf ball stops sliding on the collision surface to when the golf ball leaves the collision surface.

In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the envelope layer is formed into two layers—an inner envelope layer and an outer envelope layer. The inner envelope layer-encased sphere, outer envelope layer-encased sphere, intermediate layer-encased sphere and ball have respective surface hardness that satisfy a specific relationship. The inner envelope layer or outer envelope layer is formed primarily of one or more elastomer, and further the core has a particular hardness profile. This ball has an excellent flight when struck by golfers whose head speeds are not that fast and has a good, soft feel at impact, thus making it highly suitable for amateur golfers,

The present invention provides a method for arranging dimples on a golf ball surface in which the dimples are arranged in a pattern derived from at least one irregular domain generated from a regular or non-regular polyhedron. The method includes choosing control points of a polyhedron, generating an irregular domain based on those control points, packing the irregular domain with dimples, and tessellating the irregular domain to cover the surface of the golf ball. The control points include the center of a polyhedral face, a vertex of the polyhedron, a midpoint or other point on an edge of the polyhedron and others. The method ensures that the symmetry of the underlying polyhedron is preserved while minimizing or eliminating great circles due to parting lines.

The present invention is directed to golf balls having improved aerodynamic performance due, at least in part, to the selection of the plan shapes of the dimples thereon. In particular, the present invention is directed to a golf ball that includes at least a portion of its dimples having a plan shape defined by a periodic triangle wave function mapped along a circular closed path. In addition, the present invention provides methods for designing dimples having a plan shape defined by a periodic triangle wave function mapped along a circular closed path.

In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the intermediate layer is formed into two layers—an inner layer and an outer layer. The surface hardness of the envelope layer-encased sphere, the surface hardness of the inner intermediate layer-encased sphere, the surface hardness of the outer intermediate layer-encased sphere and the surface hardness of the ball together satisfy a specific relationship. This ball has an excellent flight when struck by golfers whose head speeds are not that fast and has a soft yet good feel at impact, thus making it highly suitable for amateur golfers.

A golf ball has a core, an inner cover, an outer cover, and dimples. The golf ball satisfies the following mathematical formulas.

Sa=4500+10(A0.5B2Cs)4000

0.04Sa+16020D0.04Sa+160+20 A: a compression (Atti) of the golfball B: a hardness difference (Shore C) between a surface and a center of the core

Cs: (HiTi+2HoTo)/(Ti+2To) D: a total volume (mm.sup.3) of the dimples Hi: a hardness (Shore D) of the inner cover Ho: a hardness (Shore D) of the outer cover Ti: a thickness (mm) of the inner cover To: a thickness (mm) of the outer cover