Abstract: A golf ball comprising a core and a cover has a number of dimples in its surface. The ball, when hit with a driver at a head speed of 50 m/s, has an effective contact area A and an apparent contact area B with the club face such that the ratio A/B is from 0.40 to 0.60. The dimple surface coverage is at least 71%. The ball has fully adequate spin and control characteristics and improved flight performance, and is well suited for use by golfers having a head speed of higher than about 40 m/s.

Abstract: A golf ball includes a core, an inner cover formed around the core, and an outer cover formed around the inner cover. A plurality of through-holes are formed in the inner cover, projections are formed on the inner surface of the outer cover at positions corresponding to the through-holes, and the inner cover and the outer cover are joined together in a state in which the projections are received in the through-holes. The ratio a/A between an area a of the core-side end surface of each projection and an area A of the outer-cover-side end surface of the projection falls within the range of 0.04 to 0.80. The ratio s/S between a sum s of the areas A of the outer-cover-side end surfaces of the projections and a surface area S of a virtual spherical surface defined by the outer surface of the inner cover falls within the range of 0.05 to 0.75.

Abstract: A solid golf ball comprises a solid core and a cover of at least one layer, the solid core having a multilayer construction which includes a center core and an outer core layer enclosing the center core. The center core is composed primarily of a thermoplastic resin or elastomer, and has a diameter of 3-18 mm and a Shore D hardness of 15-50. The outer core layer has a Shore D hardness near the interface thereof with the center core which is 1-15 units higher than the Shore D hardness of the center core. The ball has a good feel, excellent durability and good distance.

Abstract: In a golf ball comprising a core, an intermediate layer, and a cover, the core or the cover is provided with a plurality of protrusions penetrating into the intermediate layer, and the material of the protrusions has at least 8 units higher Shore D hardness than the material of the intermediate layer. The protrusions satisfy the applicable range of Euler's buckling formula. The golf ball has improved performance.

Abstract: In a golf ball comprising a core and a cover of at least two layers around the core, the cover layers including the outermost layer which is formed with a plurality of dimples, the cover outermost layer has a Shore D hardness of 30 to less than 51, and the product of the Shore D hardness of the cover outermost layer multiplied by the Shore D hardness of a cover layer disposed inside the cover outermost layer is from 1,000 to 3,500. The plurality of dimples include at least three types of dimples which are different in diameter and the ratio of average diameter to average depth of dimples is from 17 to 26. The overall dimple volume is 280-390 mm3. The ball has an improved overall profile of performance including feel, durability, rebound, approach control and flight characteristics.

Abstract: In a golf ball comprising a solid core, an intermediate layer, and a cover, the solid core or the cover is provided with a plurality of protrusions penetrating into the intermediate layer. Provided the protrusions are spaced apart a distance X (mm) and have a length L (mm), those protrusions satisfying L≦X≦5L account for at least 60% of the entire protrusions. The protrusions penetrating into the intermediate layer optimizes the buckling phenomenon whereby the ball is improved in flight performance, control and feel.

Abstract: A golf ball comprising a core, a cover inner layer and a cover outer layer has a plurality of dimples on the surface. The JIS-C hardness of the ball decreases successively within specific ranges from the cover outer layer to the cover inner layer to the core surface, but is substantially uniform within a central portion of the core. The dimples are of at least three types having different diameters and have an average diameter of 3.3-4.0 mm and an average depth of 0.11-0.17 mm, with the ratio of average diameter to average depth being from 25 to 33. The total number of dimples is from 380 to 450. The ball exhibits a relatively large deflection and a high resilience on impact which enable it to achieve an improved distance, as well as a good feel.

Abstract: In a solid golf ball comprising a solid core and a cover, the solid core has a multilayer construction which includes a center core and an outer core that encloses the center core. The center core is composed primarily of a resin and has a diameter of 3-20 mm and a specific gravity of 0.90-1.50. The center core has a surface Shore D hardness of 40-95 which is at least 10 units greater than the Shore D hardness of an innermost layer of the outer core. The ball has an excellent click and feel.

Abstract: A solid golf ball comprises a solid core and a cover of at least one layer, the solid core having a multilayer construction which includes a center core and an outer core layer enclosing the center core. The center core is composed primarily of a thermoplastic resin or elastomer, and has a diameter of 3-18 mm and a Shore D hardness of 15-50. The outer core layer has a Shore D hardness near the interface thereof with the center core which is 1-15 units higher than the Shore D hardness of the center core. The ball has a good feel, excellent durability and good distance.

Abstract: In a solid golf ball having a solid core and a cover, the solid core is composed of a core-forming material and particles of a different material. In one embodiment the particles have a higher Shore D hardness than the surface of the core. In a second embodiment, the particles also have substantially the same specific gravity as the core. In a third embodiment, the particles account for 0.1-15% of the core volume and are not exposed on the core surface. These features provide the ball with both a good click and feel, as well as excellent durability and symmetry.

Abstract: In a thread-wound golf ball including a center ball, a thread layer, and a cover, the thread layer is formed of rubber thread and resin thread mixedly wound around the center ball. The resin thread wound around the center ball together with the rubber thread is preferably formed of a resin (such as polyester resin or polyurethane resin) which has relatively high resilience and is softer than rubber thread undergone extension crystallization.

Abstract: In a golf ball comprising a core, an intermediate layer, and a cover, the core or the cover is provided with a plurality of protrusions penetrating into the intermediate layer, and the material of the protrusions has at least 8 units higher Shore D hardness than the material of the intermediate layer. The protrusions satisfy the applicable range of Euler's buckling formula. The golf ball has improved performance.

Abstract: A solid golf ball comprising a core and a cover has a number of dimples in its surface. The core has a deflection of 3.5-5.5 mm when under a load of 100 kg, and has a JIS-C hardness at its surface of at least 70 and a JIS-C hardness at its center which is at least 10 units lower than the hardness at the core surface. The ball, when hit with a driver at a head speed of 50 m/s, has an effective contact area A and an apparent contact area B with the club face such that the ratio A/B is from 0.40 to 0.60. The ball has a soft feel, fully adequate spin characteristics, and excellent control on approach shots, and is well suited for use by golfers having a head speed of less than about 40 m/s.

Abstract: In a multi-piece solid golf ball comprising a solid core, an intermediate layer, and a cover, the intermediate layer has a gage G1 of 0.8-2 mm and a Shore D hardness of 50-65, the cover has a gage G2 of 0.5-1.3 mm and a Shore D hardness of 37-53, and the intermediate layer gage G1 and the cover gage G2 satisfy [G1/(G1+G2)]×100≧45%. Upon full shots with a driver, the ball gains a reduced spin rate and an increased initial velocity, which lead to an increase in travel distance.

Abstract: In a golf ball comprising a solid core, an intermediate layer, and a cover, the solid core or the cover is provided with a plurality of protrusions penetrating into the intermediate layer. Provided the protrusions are spaced apart a distance X (mm) and have a length L (mm), those protrusions satisfying L≦X≦5L account for at least 60% of the entire protrusions. The protrusions penetrating into the intermediate layer optimizes the buckling phenomenon whereby the ball is improved in flight performance, control and feel.

Abstract: A golf ball having a core and a cover of at least two layers around the core, wherein the outermost layer of the cover layers is formed with a plurality of dimples. The core has a deflection of 3.0-6.0 mm under a load of 100 kg. The cover outermost layer has a Shore D hardness of 51 to less than 58, and the product of the Shore D hardness of the cover outermost layer multiplied by the Shore D hardness of a cover layer disposed inside the cover outermost layer is from 1,500 to 4,000. The plurality of dimples include at leas three types of dimples which are different in diameter and the ratio of average diameter to average depth of dimples is from 21 to 28. The overall dimple volume is 270-350 mm3. The ball has an improved overall profile of performance including approach control, feel, durability, rebound and flight characteristics.

Abstract: In a golf ball comprising a core and a cover of at least two layers around the core, the cover layers including the outermost layer which is formed with a plurality of dimples, the core undergoes a deflection of 3.0-6.0 mm under a load of 100 kg, the cover outermost layer has a Shore D hardness of 58-70, and the product of the Shore D hardness of the cover outermost layer multiplied by the Shore D hardness of a cover layer disposed inside the cover outermost layer is 1,500-5,000. The plurality of dimples include at least three types of dimples which are different in diameter and/or depth, and the ratio of average diameter to average depth of the dimples is from 27/1 to 33/1. The overall dimple volume is 260-340 mm3. The ball has an improved overall profile of performance including feel, durability, rebound and flight characteristics.

Abstract: A solid golf ball having a multilayer structure including a S core of one or more layers, an enclosing layer, an intermediate layer, and a cover of one or more layers. The intermediate layer is made of a cis-1,4-polybutadiene base rubber composition, and the enclosing layer is composed primarily of a resin material. The enclosing layer and the intermediate layer have a difference in hardness at the boundary therebetween within ±3 JIS-C hardness units. The ball has excellent durability and a good feel when hit with a golf club.

Abstract: A golf ball includes a core, an intermediate layer, and a cover. At a boundary between the core and the intermediate layer or at a boundary between the intermediate layer and the cover, convex ribs are formed in a network pattern on a first layer such that the convex ribs intrude into a second layer. In addition, columnar projections are formed on the first layer at positions corresponding to the nodes of the network pattern such that the columnar projections intrude into the second layer deeper than the convex ribs.

Abstract: In a solid golf ball of four or multilayer structure comprising a core, an enclosing layer, an intermediate layer, and a cover, the core is comprised primarily of a thermoplastic resin or thermoplastic elastomer and has a diameter of 3-18 mm and a Shore D hardness of 15-50, the enclosing layer is comprised primarily of a thermoplastic resin or thermoplastic elastomer, and the enclosing layer and the intermediate layer have a substantially equal Shore D hardness at a boundary therebetween. The golf ball offers pleasant feel when hit, improved durability, and increased distance.