Sumitomo Rubber Industries Limited

Dunlop Sports Company Limited

Hironori Takihara

Takahiro Sajima

Toshiyuki Takubo

Hikaru Nagakura

Kohei Mimura

Kai Hayashi

Kuniyasu Horiuchi

Yosuke Yamamoto

Hidetaka Inoue

Kosuke Tachibana

A golf ballincludes a coreand a coverpositioned outside the core. The coveris formed in a mold having support pins by injection molding. A ratio (V/S) of a volume V (mm) of the coverto an amount of compressive deformation S (mm) of the coreis not less than 1000 and not greater than 1900. The coverhas a shore D hardness of not greater than 62. The golf ballhas a plurality of dimpleson a surface thereof. A total volume W of these dimples is not less than 490 mmand not greater than 620 mm. A ratio (&#x3b1;/P) of a latitude &#x3b1; (degree) of each support pin to a total cross-sectional area P (mm) of the support pins is not less than 0.35 and not greater than 0.60.

Golf ball

An object of the present invention is to provide a golf ball traveling a great flight distance and having a good shot feeling on long iron shots. The present invention provides a golf ball comprising a core, at least one intermediate layer covering the core and a cover covering the intermediate layer, wherein the core is formed from a core rubber composition containing (a) a base rubber containing a polybutadiene, (b) an &#x3b1;,&#x3b2;-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 (d) a terpene-based resin, and a material hardness (Hm) of the intermediate layer is higher than a material hardness (Hc) of the cover, and the material hardness (Hc) of the cover is 50 or more in Shore D hardness.

A golf ball has a plurality of dimplesand a landon a surface thereof. The golf ball further has a large number of minute projectionsformed on surfaces of the dimplesand the land. The surface of the golf ball has an arithmetic average height Sa of not less than 0.5 &#x3bc;m and not greater than 30 &#x3bc;m. An average value Hav of heights H of the minute projectionsis not less than 0.5 &#x3bc;m and not greater than 50 &#x3bc;m. A ratio Pp of a sum of areas of all the minute projectionsto a surface area of a phantom sphere of the golf ball is not less than 7%. An average value Dav of diameters D of the minute projectionsis not less than 5 &#x3bc;m and not greater than 50 &#x3bc;m.

An object of the present invention is to provide a golf ball traveling a great flight distance and having a good shot feeling and durability on driver shots. The present invention provides a golf ball comprising a core, at least one intermediate layer covering the core and a cover covering the intermediate layer, wherein the core is formed from a core rubber composition containing (a) a base rubber containing a polybutadiene, (b) an &#x3b1;,&#x3b2;-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 (d) a terpene-based resin, and a material hardness (Hm) of the intermediate layer and a material hardness (Hc) of the cover satisfy an equation of Hm&#x2264;Hc.

An object of the present invention is to provide a golf ball traveling a great flight distance and having a good shot feeling on long iron shots. The present invention provides a golf ball comprising a core, at least one intermediate layer covering the core and a cover covering the intermediate layer, wherein the core is formed from a core rubber composition containing (a) a base rubber containing a polybutadiene, (b) an &#x3b1;,&#x3b2;-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 (d) a terpene-based resin, and a material hardness (Hm) of the intermediate layer is higher than a material hardness (Hc) of the cover, and the material hardness (Hc) of the cover is less than 50 in Shore D hardness.

A golf ball has a plurality of dimplesand a landon a surface thereof. The golf ball further has a large number of minute projectionsformed on surfaces of the dimplesand the land. The minute projectionsare exposed on the surface of the golf ball. The surface of the golf ball has an arithmetic average height Sa of not less than 0.5 &#x3bc;m and not greater than 30 &#x3bc;m. The surface of the golf ball has a maximum height Sz of not less than 5 &#x3bc;m and not greater than 200 &#x3bc;m.

A golf ball has a main bodyand a paint layerpositioned outside the main body. The main bodyhas a plurality of minute projectionson a surface thereof. The paint layerhas a thickness Tp of not less than 5 &#x3bc;m and not greater than 30 &#x3bc;m. Each minute projectionis embedded in the paint layer. An average value Hav of heights H of the minute projectionsis not less than 0.5 &#x3bc;m and not greater than 80% of the thickness Tp. A ratio Pp of a sum of areas of all the minute projectionsto a surface area of a phantom sphere of the golf ball is not less than 7%. An average value Dav of diameters D of the minute projectionsis not less than 5 &#x3bc;m and not greater than 50 &#x3bc;m.

A golf ballincludes a coreand a cover. An amount of compressive deformation Df of the coreis equal to or greater than 4.1 mm. A nominal thickness T of the coveris equal to or less than 1.70 mm. The golf ballhas a plurality of dimpleson a surface thereof. A value V calculated by the following mathematical formula is equal to or less than 290.In the mathematical formula, N represents a total number of the dimples, So represents a ratio of a total area of all the dimplesrelative to a surface area of a phantom sphere of the golf ball, and Bb represents an average (mm) of thicknesses B of the coverimmediately below deepest points of the dimples

Two-piece golf ball

A golf ball () includes a core (), an inner cover (), a main cover (), and an outer cover (). X=Hc&#xd7;Rc&#xd7;0.05, S=Hs&#xd7;Rc&#xd7;0.05, M=Hm&#xd7;Tm, I=Hi&#xd7;Ti, O=Ho&#xd7;To, and Q=(I+O)/2 that are calculated from a radius Rc of the core (), a Shore C hardness Hc at a central point of the core (), a Shore C hardness Hs at a surface of the core (), a thickness Tm of the main cover (), a Shore C hardness Hm of the main cover (), a thickness Ti of the inner cover (), a Shore C hardness Hi of the inner cover (), a thickness To of the outer cover () and a Shore C hardness Ho of the outer cover (), satisfy 15&#x2264;M&#x2212;S&#x2264;100, 0.25&#x3c;Q/M&#x3c;0.5, &#x2212;10&#x2264;I&#x2212;O&#x2264;30, and Q/X&#x3c;0.8.

A golf ballincludes a core, a mid layerpositioned outside this core, and a coverpositioned outside this mid layer. When a total thickness of the mid layerand the coveris denoted by L (mm), a Shore C hardness at a point A away from a surface of the coretoward a central point of the coreby 5L (mm) is denoted by Ha, a Shore C hardness at a point B away from the surface of the coretoward the central point of the coreby 2.5L (mm) is denoted by Hb, and a Shore C hardness at the central point of the coreand Shore C hardnesses of the mid layerand the coverare denoted by H0, Hm, and Hc, respectively; the golf ballsatisfies Hc&#x2212;Hb&#x3e;0, Hm&#x2212;H0&#x3e;0, and Ha&#x2212;Hm&#x3e;0.

A golf ball () includes a core (), an inner cover (), a main cover (), and an outer cover (). X=Hc&#xd7;Rc&#xd7;0.05, S=Hs&#xd7;Rc&#xd7;0.05, M=Hm&#xd7;Tm, I=Hi&#xd7;Ti, O=Ho&#xd7;To, and Q=(I+O)/2 that are calculated from a radius Rc of the core (), a Shore C hardness Hc at a central point of the core (), a Shore C hardness Hs at a surface of the core (), a thickness Tm of the main cover (), a Shore C hardness Hm of the main cover (), a thickness Ti of the inner cover (), a Shore C hardness Hi of the inner cover (), a thickness To of the outer cover () and a Shore C hardness Ho of the outer cover (), satisfy 15&#x2264;M&#x2212;S&#x2264;100, 0.25&#x3c;Q/M&#x3c;0.5, &#x2212;10&#x2264;I&#x2212;O&#x2264;30, and Q/X&#x2265;0.8.

A golf ballincludes a core, one or more mid layers, a cover, and dimples. A central hardness Ho and a surface hardness Hs of the core, a hardness Hm(min) of a layer having a lowest hardness among the mid layers, and a hardness Hc of the coversatisfy the following mathematical formulas (1) to (4).&#x3e;15&#x2003;&#x2003;(1)(min)&#x3e;20&#x2003;&#x2003;(2)&#x2212;10&#x3c;(min)&#x2212;&#x3c;15&#x2003;&#x2003;(3)5&#x3c;&#x3c;20&#x2003;&#x2003;(4)An occupation ratio So and a ratio Rs of a number of the dimpleseach having a diameter of from 9.60% to 10.37% of a diameter of the golf ball, relative to a total number of the dimples, satisfy the following mathematical formula (5).&#x2265;&#x2212;2.5*+273&#x2003;&#x2003;(5).

An object of the present invention is to provide a golf ball traveling a great distance on driver shots and on iron shots. The present invention provides a golf ball comprising a spherical core including an inner layer and an outer layer, and a cover, wherein a difference (H&#x2212;H) between a hardness (H) at a point outwardly away in a radial direction from a boundary between the inner layer and the outer layer of the spherical core by 1 mm and a hardness (H) at a point inwardly away in the radial direction from the boundary between the inner layer and the outer layer of the spherical core by 1 mm is 0 or more in Shore C hardness, a surface hardness (H) of the spherical core is more than 65 in Shore C hardness, an angle &#x3b1; of a hardness gradient of the inner layer is 0&#xb0; or more, a difference (&#x3b1;&#x2212;&#x3b2;) between the angle &#x3b1; and an angle &#x3b2; of a hardness gradient of the outer layer is 0&#xb0; or more, a thickness of the cover is 3 mm or less, a difference (Hc&#x2212;H) between a hardness (Hc) of the cover and the surface hardness (H) of the spherical core is 2 or more in Shore C hardness, and the cover has a highest hardness among the constituent members of the golf ball.

A golf ball has a large number of dimpleson a surface thereof. The dimplesinclude a plurality of small dimplesS each having an area of less than 8.0 mm, and a plurality of large dimplesL each having an area of equal to or greater than 8.0 mm. A ratio PS of a sum of areas of all the small dimplesS to a surface area of a phantom sphere of the golf ball is less than 2.0%. A ratio PL of a sum of areas of all the large dimplesL to the surface area of the phantom sphere is equal to or greater than 79.0%. A degree G of uniformity of areas of the large dimplesL is equal to or less than 1.15.

Growing community of inventors

Kobe, Japan

Hironori Takihara