A multi-piece solid golf ball having a two-layer core with an inner core layer and an outer core layer and having a cover of one or more layer with numerous dimples on the surface is characterized in that the hardest cover layer has a specific material hardness and the ball has a specific value obtained by subtracting the surface hardness of the overall core from the surface hardness of the hardest cover layer, a specific deflection, and a specific value obtained by subtracting the initial velocity of the inner core layer from the initial velocity of the sphere consisting of the inner core layer encased by the outer core layer. This golf ball enables relatively low head speed golfers to achieve a good distance on full shots with drivers and iron clubs and also provides a soft, comfortable feel at impact.

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.

An object of the present invention is to provide a golf ball excellent in flying performance, in particular, to provide a golf ball traveling a great flight distance. The present invention provides a golf ball having a spherical core and at least one cover layer covering the spherical core, wherein the spherical core is formed from a rubber composition containing (a) a base rubber, (b) an ,-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, and (d1) an aromatic carboxylic acid or (d2) an aromatic carboxylic acid salt, provided that the rubber composition further contains (e) a metal compound in the case of containing only (b) the ,-unsaturated carboxylic acid having 3 to 8 carbon atoms as the co-crosslinking agent.

The present invention relates to golf balls, specifically to a golf ball comprising an aerodynamic pattern having novel shaped dimple structures which reduce the variation in airflow turning angle thereby improving the golf ball's flight performance. The dimple structures have a conical shaped base with a dimple in the center and reduced or no flat land areas between the dimples.

In a golf ball, dimples are arranged on a spherical polyhedron formed by dividing a surface of a sphere using small circles and great circles only on the equator, without arranging the dimples on a spherical polyhedron formed by dividing a surface of a sphere using great circles. The formed spherical polyhedron includes two spherical regular hexagons centered on a pole, twelve near-pole spherical isosceles triangles, twelve near-equator spherical pentagons, and twelve near-equator spherical isosceles triangles, in which the dimples are arranged. Thus, a dimple area ratio may be improved by 2 to 4%, compared to the prior art in which dimples are arranged in spherical polygons of a cubeoctahedron (or an octahedron) divided by great circles.

A golf ball with an aerodynamic design is disclosed herein. The aerodynamic design has a protrusion at a center of a hex geometry representing an increase in ball radius greater than 0.0005 inches from a minimum ball radius. The minimum ball radius is located between 0.01 and 0.04 inch (11%-46%) from the center of the hex geometry.

A surface of a sphere is divided by using not only great circles but also small circles, forming a spherical polyhedron. The spherical polyhedron includes two spherical regular pentagons, each having a center at the pole, ten spherical isosceles triangles near the pole, ten spherical pentagons near the equator, and ten other spherical isosceles triangles near the equator. Compared to a related art, dimples are accurately arranged in spherical polygons. Thus, a dimple area ratio is improved and the number of dimples is appropriately maintained.

The present invention is directed to golf balls having surface textures with unique appearances and improved aerodynamic characteristics due, at least in part, to the use of curvilinear dimple plan shapes. 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 number of convex or concave arcs that are derived from the vertices of a regular n-sided polygon, for example, an equilateral triangle or square.

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.

A golf ball includes a plurality of dimples on the surface thereof and satisfies the following expression (1):
PS.sub.7/S/H1006.25 (mm.sup.1)(1),
wherein H is a deformation amount, which is expressed by a compressive deformation amount of the golf ball; S is a virtual plane area, which is a surface area of the golf ball determined supposing that no dimple exists on the surface of the golf ball; and PS.sub.7 is a pressurized area, which is an area of the golf ball contacting a plane when a load of 6864 N is applied to the golf ball. The bottom of the dimple includes a center protruding portion with a curved shape protruding toward an outside of the golf ball.