Abstract: A golf ball 2 includes a spherical core 4 and a cover 6 covering the core 4. The cover 6 includes an inner cover 8 and an outer cover 10 positioned outside the inner cover 8. The core 4 is obtained by a rubber composition being crosslinked. The rubber composition includes a base rubber (a), a co-crosslinking agent (b), a crosslinking initiator (c), and a carboxylate (d). The co-crosslinking agent (b) is: (b1) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms; or (b2) a metal salt of an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms. The amount of the carboxylate (d) is equal to or greater than 1 parts by weight but less than 40 parts by weight per 100 parts by weight of the base rubber (a). A hardness of an innermost layer of the cover is greater than a surface hardness of the core.

Abstract: A golf ball 2 includes a core 4, a mid layer 6 and a cover 8. The golf ball 2 further includes a large number of dimples 10 on a surface thereof. The surface has a northern hemisphere N and a southern hemisphere S. Each of the hemispheres has a high-latitude region 14, a mid-latitude region 18 and a low-latitude region 16. The number of planes that can divide a dimple pattern of the hemisphere so that divided dimple patterns are mirror symmetry to each other is one. Neither a dimple pattern of the high-latitude region 14 nor a dimple pattern of the low-latitude region 16 is rotationally symmetrical. A product THm of a thickness and a hardness for the mid layer 6, and a product THc of a thickness and a hardness for the cover 8 satisfy the following mathematical formula.

Abstract: The present invention provides a golf ball comprising a golf ball body with a spherical core having one or more layers, an intermediate layer disposed outside the spherical core and a cover disposed outside the intermediate layer and a paint film formed on a surface of the golf ball body, and having a friction coefficient calculated using a contact force tester of 0.35 or more and 0.60 or less, wherein the golf ball body has specific plurality of dimples on the surface thereof, at least one layer of the spherical core is a rubber layer having a specific hardness distribution, and the rubber layer has a hardness at the outermost point which is greater than a hardness at the innermost point, and the intermediate layer has a slab hardness (Hm) which is greater than a slab hardness (Hc) of the cover.

Abstract: The surface of a golf ball 2 is divided by four comparting great circles CG into six spherical quadrangles Ss and eight spherical triangles St. The eight spherical triangles St are composed of four first spherical triangles St1 and four second spherical triangles St2. Dimple patterns of the six spherical quadrangles Ss are the same. Dimple patterns of the four first spherical triangles St1 are the same. Dimple patterns of the four second spherical triangles St2 are the same. The dimple pattern of each first spherical triangle St1 is different from the dimple pattern of each second spherical triangle St2. The comparting great circles CG are obtained by projecting the 24 sides of a cuboctahedron inscribed in a phantom sphere of the golf ball 2 on the surface of the phantom sphere.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, a cover 8 and a paint layer 10. The core 4 includes a center 12 and an envelope layer 14. The golf ball 2 satisfies the following mathematical formulas. In the mathematical formulas, Tm represents a thickness of the mid layer, Tcmin represents a minimum thickness of the cover, Tcmax represents a maximum thickness of the cover, and Tp represents a thickness of the paint layer. The golf ball 2 has a large number of dimples 16 on a surface thereof. The number of planes that can divide a pattern of the dimples so that divided patterns are mirror symmetry to each other is one. Tm>Tcmax?Tcmin>Tp (Tcmas?Tcmin)?0.15 mm 0.15?(Tp/Tcmin)?0.

Abstract: A golf ball 2 includes a center 8, a mid layer 10, a cover 6 and dimples 12. The cover 6 has a Shore D hardness of 30-50. The golf ball 2 has an amount of compressive deformation of 3.0-5.0 mm. The ball 2 meets a mathematical formula (I): 0.80?((L1+L2)/2)?0.95??(I). L1 represents a ratio of a lift coefficient CL1 relative to a drag coefficient CD1, the lift coefficient CL1 and the drag coefficient CD1 being measured under conditions of a Reynolds number of 1.290×105 and a spin rate of 2820 rpm. L2 represents a ratio of a lift coefficient CL2 relative to a drag coefficient CD2, the lift coefficient CL2 and the drag coefficient CD2 being measured under conditions of a Reynolds number of 1.771×105 and a spin rate of 2940 rpm.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, a cover 8 and a paint layer 10. The core 4 includes a center 12 and an envelope layer 14. The golf ball 2 satisfies the following mathematical formulas. In the mathematical formulas, Hm represents a Shore D hardness of the mid layer, Hc represents a Shore D hardness of the cover, and Hb represents a Shore D hardness of the surface of the golf ball. The golf ball 2 has a large number of dimples 16 on a surface thereof. The number of planes that can divide a pattern of the dimples so that divided patterns are mirror symmetry to each other is one.

Abstract: A golf ball has a large number of dimples on a surface thereof. The golf ball meets the following mathematical formula (I): 1.320?L1?1.420 (I), where L1 represents a ratio of a lift coefficient CL1 which is measured under conditions of a Reynolds number of 1.290×105 and a spin rate of 2820 rpm, relative to a lift coefficient CL2 which is measured under conditions of a Reynolds number of 1.290×105 and a spin rate of 1740 rpm.

Abstract: A golf ball 2 includes a large number of dimples 10 on a surface thereof. The surface has a northern hemisphere N and a southern hemisphere S. Each of the hemispheres has a high-latitude region 14, a mid-latitude region 18 and a low-latitude region 16. The high-latitude region 14 has a latitude range of 40° or greater but 90° or less. The mid-latitude region 18 has a latitude range of 20° or greater but less than 40°. The low-latitude region 16 has a latitude range of 0° or greater but less than 20°. The number of planes that can divide a dimple pattern of the hemisphere so that divided dimple patterns are mirror symmetry to each other is one. Neither a dimple pattern of the high-latitude region 14 nor a dimple pattern of the low-latitude region 16 is rotationally symmetrical.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, and a cover 8. The core 4 includes a center 10 and an envelope layer 12. The ratio of the volume Ve of the core 4 to the volume of a phantom sphere of the golf ball 2 is equal to greater than 76%. The ratio (Co/Ce) of an amount of compressive deformation Co of the center 10 to an amount of compressive deformation Ce of the core 4 is greater than 2.0 but less than 3.0. The ratio (Vo/Ve) of the volume Vo of the center 10 to the volume Ve of the core 4 is equal to or greater than 0.01 but equal to or less than 0.13.

Abstract: A golf ball that enhances flight performance is provided. A golf ball according to the present invention includes a spherical core, at least one cover member that covers the core, and a coating layer that covers the cover member configuring the outermost layer. A plurality of dimples are formed in the cover member configuring the outermost layer. Roughness is formed on a surface of the coating layer such that a relationship between a drag coefficient CD1 and a lift coefficient CL1 when a golf ball is hit with a Reynolds number of 1.771×105 and a spin amount of 2280 rpm satisfies CD1×CL1<0.0370.

Abstract: A golf ball that enhances flight performance is provided. A golf ball according to the present invention includes a spherical core, at least one cover member that covers the core, and a coating layer that covers the cover member configuring the outermost layer. A plurality of dimples are formed in the cover member configuring the outermost layer. The thickness of the coating layer is 5.0 ?m or more. Roughness is formed on the surface of the coating layer after coating the cover member configuring the outermost layer. The maximum height Rz and the arithmetic average roughness Ra of the surface of the coating layer satisfy the relationship Rz?Ra×6.0.

Abstract: An object of the present invention is to provide a golf ball having an improved controllability and shot feeling while maintaining a flight distance on driver shots. The present invention provides a golf ball having a core, an intermediate layer disposed around the core, and a cover disposed around the intermediate layer, wherein the core has a center and an envelope layer disposed around the center, and has a specific hardness distribution, and the intermediate layer is formed from an intermediate layer composition comprising, as a resin component, (A) a modified polyester elastomer and (B) a binary ionomer resin, and having a flexural modulus ranging from 150 MPa to 450 MPa, a maximum loss factor (tan ?) between ?20° C. and 0° C. of 0.08 or less, a repulsive modulus of 55% or more, and a slab hardness ranging from 60 to 90 in JIS-hardness.

Abstract: A golf ball has a large number of dimples on a surface thereof. The golf ball meets the following mathematical formula (I): Su?9.0*So?6.04??(I), Where: So represents a ratio of a sum of spherical surface areas of all the dimples to a surface area of a phantom sphere of the golf ball; and Su represents a standard deviation (mm2) of the spherical surface areas of all the dimples. Preferably, the ratio So is equal to or greater than 0.780. Preferably, the standard deviation Su is equal to or less than 2.150 mm2. Preferably, a number of the dimples is equal to or greater than 300 but equal to or less than 390. Preferably, an average Sa of the spherical surface areas s of all the dimples is equal to or greater than 14.00 mm2.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, and a cover 8. The core 4 includes a center 10 and an envelope layer 12. The ratio (Do/De) of an amount of compressive deformation Do of the center 10 to an amount of compressive deformation De of the core 4 is equal to or greater than 1.5 but equal to or less than 2.5. The ratio (Do/Dc) of the amount of compressive deformation Do of the center 10 to an amount of compressive deformation Dc of the golf ball 2 is equal to or greater than 1.8. The diameter of the center 10 is equal to or less than 20 mm. The difference (He?Ho) between a surface hardness He of the core 4 and a central hardness Ho of the center 10 is equal to or less than 40.

Abstract: A golf ball 2 includes a spherical core 4, a mid layer 6 outside the core 4, and a cover 8 outside the mid layer 6. The core 4 includes a spherical center 10 and an envelope layer 12 outside the center 10. At all points P included in a zone that extends over a distance range from equal to or greater than 1 mm to equal to or less than 15 mm from the central point of the core 4, the following mathematical formula is satisfied. ?5<H2?H1<5 In the mathematical formula, H1 indicates the JIS-C hardness at a point P1 located radially inward of each point P at a distance of 1 mm from the point P, and H2 indicates the JIS-C hardness at a point P2 located radially outward of each point P at a distance of 1 mm from the point P.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, and a cover 8. The core 4 includes a center 10 and an envelope layer 12. The ratio of the volume Ve of the core 4 to the volume of a phantom sphere of the golf ball 2 is equal to greater than 76%. The ratio (Co/Do) of an amount of compressive deformation Co of the center 10 to the diameter Do of the center 10 is equal to or greater than 0.085 but equal to or less than 0.130. The ratio (Ce/De) of an amount of compressive deformation Ce of the core 4 to the diameter De of the core 4 is equal to or greater than 0.015 but equal to or less than 0.020.

Abstract: Mold 2 includes a pair of mold halves (upper mold half 4 and lower mold half 6). A spherical cavity is formed by mating upper mold half 4 and lower mold half 6. A large number of pimples 10 are provided on the cavity face of the upper mold half 4 and lower mold half 6. The upper mold half 4 and the lower mold half 6 have flat plane 14, protrusion 16 and recess 18, respectively. The protrusion 16 projects from the equator Eq. The recess 18 is depressed from the equator Eq. The protrusion 16 includes a part of the pimple 10. The proportion P1 of the number of the protrusion 16 that is adjacent to other protrusion 16 belonging to other mold half distinct from the mold half to which itself belongs, to the total number of the protrusions 16 is equal to or greater than 50%. The proportion Pw of the sum total of the widths of the protrusions 16 measured along the equator, to the entire length of the equator is equal to or greater than 35%.

Abstract: A golf ball has, on a surface thereof, a rugged pattern composed of a land and a large number of dimples. A method for designing the rugged pattern includes the steps of: (1) assuming a large number of circles on a surface of a phantom sphere; (2) assuming a large number of generating points 16 based on positions of the large number of circles; (3) assuming a large number of Voronoi regions 18 on the surface of the phantom sphere by a Voronoi tessellation based on the large number of generating points 16; and (4) assigning a dimple and a land to the surface of the phantom sphere based on contours of the large number of Voronoi regions 18.

Abstract: Golf ball wherein, at all points Pa included in zone “A” away from the central point of its core at a distance of ?1 mm and <5 mm, this mathematical expression is satisfied: Ha2?Ha1<5, wherein Ha1 and Ha2 each represents hardness at a point located respectively inside a point Pa and outside the point Pa. Also, at any point Pb included in zone “B” away from the central point of its core at a distance of ?5 mm and ?10 mm, this mathematical expression is satisfied: Hb2?Hb1?5, wherein Hb1 and Hb2 each represents hardness at a point located respectively inside a point Pb and outside the point Pb. This hardness distribution provides a golf ball with reduced energy loss when hit with a driver, and with excellent control performance when hit with a short iron.