Bridgestone Sports Co., Ltd.

Bridgestone Corporation

Junji Umezawa

Hiroshi Higuchi

Shinichi Kakiuchi

Hideo Watanabe

Daisuke Arai

Kae Iizuka

Yasushi Ichikawa

Hirotaka Shimosaka

Hiroyuki Nagasawa

Takashi Maruko

Kazufumi Tabata

Atsuki Kasashima

Rinya Takesue

Kunitoshi Ishihara

Nobuhiko Matsumura

Toru Ogawana

Yutaka Masutani

Takashi Ohira

Shinichi Hinomoto

Katsunori Sato

Jun Shindo

Takuma Nakagawa

Hidekazu Saito

Yoshihiro Yamana

Hiroki Kimura

Shinich Kakiuchi

A multi-piece solid golf ball has a core, an envelope layer encasing the core, an intermediate layer encasing the envelope layer, and an outer layer which encases the envelope layer and has formed on a surface thereof a plurality of dimples. The core is made of an elastomer. The envelope layer is formed of an inner envelope layer and an outer envelope layer, and the intermediate layer is formed of an inner intermediate layer and an outer intermediate layer. Letting the average hardness of the core be expressed by the following formula: average core hardness (Shore D)=[core surface hardness (Shore D)+core center hardness (Shore D)]/2, the outer layer has a hardness (Shore D) which is higher than the average core hardness and each of the envelope layers and the intermediate layers is softer than the outer layer.

Multi-piece solid golf ball

A multi-piece solid golf ball has a core, an envelope layer encasing the core, an intermediate layer encasing the envelope layer, and a cover which encases the intermediate layer and has formed on a surface thereof a plurality of dimples. The envelope layer is formed of an inner envelope layer, an intermediate envelope layer and an outer envelope layer. The inner, intermediate and outer envelope layers, the intermediate layer and the cover are each formed primarily of a resin material which may be of the same or different types, and the core is formed primarily of a rubber material. The golf ball has an excellent flight performance and also excellent controllability in the short game. In addition, it has a good feel on impact and an excellent scuff resistance.

A multi-piece solid golf ball having a core, an envelope layer having an inner envelope layer, intermediate envelope layer and outer envelope layer, an intermediate layer, and a cover having a plurality of dimples formed on a surface thereof, arranged in that order. The three envelope layers, intermediate layer and cover are each formed primarily of a resin material of the same or different types. The core is formed primarily of a rubber material, and has a material hardness higher than the core center hardness. One of the inner layers has a material hardness higher than either or both of the cover material hardness and the average core hardness. The golf ball lowers the spin rate on full shots with a driver, increases the distance traveled by the ball, has good controllability, maintains a straight path particularly on full shots, has a good feel on impact and excellent scuff resistance.

The invention provides a multi-piece solid golf ball having a solid core encased by a cover of one, two or more layers, which ball has specific hardness relationships among various areas on a core cross-section obtained by cutting the solid core in half. The golf ball has a reduced spin rate on shots with a driver (W#1) and thus is able to achieve an increased distance. A good feel on impact can also be obtained.

The invention provides a multi-piece solid golf ball having a solid core encased by a cover of one, two or more layers, which ball has specific hardness relationships among various areas on a core cross-section obtained by cutting the solid core in half. The golf ball has both a reduced spin rate and a good initial velocity on shots, particularly when struck in a high head-speed range, and thus is able to achieve an increased distance. A good feel on impact can also be obtained.

A multi-piece solid golf ball composed of a solid core having an inner core layer and an outer core layer encased by a cover including at least an inner cover layer and an outer cover layer. The inner core layer has a JIS-C cross-sectional hardness of from 60 to 83 at any single point on a cross-section, and has a cross-sectional hardness difference between any two points on the cross-section of within &#xb1;5. The ball has specific relationships between the hardness of the inner core layer 1 mm inside a boundary between the inner core layer and the outer core layer, the hardness of the outer core layer 1 mm outside the boundary, and the surface hardness of the outer core layer. And, the outer cover layer has the specific thickness and Shore D hardness, which is higher than that of the inner cover layer.

A multi-piece solid golf ball has an elastomer core, an envelope layer encasing the core, an intermediate layer encasing the envelope layer, and an outer layer encasing the envelope layer and has dimples formed on a surface thereof. The envelope layer is formed of an inner envelope layer and an outer envelope layer, and the intermediate layer is formed of an inner intermediate layer and an outer intermediate layer. Letting the average hardness of the core be expressed by the formula: average core hardness (Shore D)=[core surface hardness (Shore D)+core center hardness (Shore D)]/2, the outer layer has a hardness (Shore D) which is higher than the average core hardness and each of the envelope layers and the intermediate layers is softer than the outer layer. The multi-piece solid golf ball provides a good, soft feel on impact and excellent flight for golfers not having a very high head speed.

A multi-piece solid golf ball composed of a solid core having an inner core layer and an outer core layer encased by a cover including at least an inner cover layer and an outer cover layer. The inner core layer has a JIS-C cross-sectional hardness of from 60 to 83 at any single point on a cross-section, and has a cross-sectional hardness difference between any two points on the cross-section of within &#xb1;5. The ball has specific relationships between the hardness of the inner core layer 1 mm inside a boundary between the inner core layer and the outer core layer, the hardness of the outer core layer 1 mm outside the boundary, and the surface hardness of the outer core layer. And, the outer cover layer has the specific Shore D hardness, which is lower than that of the inner cover layer.

The present invention provides a golf ball composed of a core and a cover having an outside surface on which are formed a plurality of dimples. Letting BV and CV be the initial velocity (m/s) of, respectively, the ball and the core as measured by a method using an initial velocity measuring apparatus of the same type as a USGA drum rotation-type initial velocity instrument and letting BE and CE be the deflection (mm) of, respectively, the ball and the core when compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf), the core initial velocity CV is from 70.0 to 78.0 m/s and the ball satisfies the formula &#x2212;1.0&#x2266;(BV/BE)&#x2212;(CV/CE)&#x2266;3.0. The golf ball of the invention has a flight distance that can be reduced compared with official golf balls currently in use, yet has the same good feel on impact and excellent controllability, scuff resistance and durability to repeated impact as a game ball.

Golf ball

A multi-piece solid golf ball composed of a solid core having an inner core layer and an outer core layer encased by a cover including at least an inner cover layer and an outer cover layer. The inner core layer has a JIS-C cross-sectional hardness of from 60 to 83 at any single point on a cross-section, and has a cross-sectional hardness difference between any two points on the cross-section of within &#xb1;5. The ball has specific relationships between the hardness of the inner core layer 1 mm inside a boundary between the inner core layer and the outer core layer, the hardness of the outer core layer 1 mm outside the boundary, and the surface hardness of the outer core layer. And, the difference in Shore D hardness between the inner cover layer and the outer cover layer is within &#xb1;5.

A multi-piece solid golf ball composed of a solid core having an inner core layer and an outer core layer encased by a cover of one or more layer. The inner core layer has a JIS-C cross-sectional hardness of from 60 to 83 at any single point on a cross-section obtained by cutting the inner core layer in half, and has a cross-sectional hardness difference between any two points on the cross-section of within &#xb1;5. The ball has specific relationships between the hardness of the inner core layer 1 mm inside a boundary between the inner core layer and the outer core layer, the hardness of the outer core layer 1 mm outside the boundary, and the surface hardness of the outer core layer.

A multi-piece solid golf ball composed of a solid core having an inner core layer and an outer core layer encased by a cover of one or more layer. The inner core layer has a JIS-C cross-sectional hardness of from 60 to 83 at any single point on a cross-section, and has a cross-sectional hardness difference between any two points on the cross-section of within &#xb1;5. The ball has specific relationships between the hardness of the inner core layer 1 mm inside a boundary between the inner core layer and the outer core layer, the hardness of the outer core layer 1 mm outside the boundary, and the surface hardness of the outer core layer.

A multi-piece solid golf ball having a core, an envelope layer formed of an inner envelope layer, an intermediate envelope layer and an outer envelope layer, an intermediate layer, and a cover having a plurality of dimples on a surface thereof, arranged in that order. The three envelope layers, intermediate layer and cover are each formed primarily of a resin material of the same or different types. The core is formed primarily of a rubber material, and has a material hardness same as or lower than the core center hardness. One of the inner layers has a material hardness higher than the cover material hardness and/or the average core hardness. The golf ball has excellent flight performance, excellent controllability in the short game, a good feel on impact and excellent scuff resistance.

The invention provides a multi-piece solid golf ball composed of a solid core, a cover, at least one intermediate layer situated therebetween, and a plurality of dimples on a surface of the ball. The diameter of the solid core, the deflection of the core when compressed under a final load of 130 kgf from an initial load of 10 kgf, the hardness at the center of the core, the hardness in a region 5 mm to 10 mm from the center of the core, the hardness 15 mm from the center of the core, and the surface hardness are set within specific ranges. The intermediate layer is composed primarily of a material obtained by mixing under applied heat a specific resin composition. The golf ball of the invention has an excellent flight performance, feel, controllability and scuff resistance.

The invention provides a multi-piece solid golf ball composed of a solid core, a cover, at least one intermediate layer situated therebetween, and a plurality of dimples on a surface of the ball. The diameter of the solid core, the deflection of the core when compressed under a final load of 130 kgf from an initial load of 10 kgf, the hardness at the center of the core, the hardness in a region 5 mm to 10 mm from the center of the core, the hardness 15 mm from the center of the core, and the surface hardness are set within specific ranges. The intermediate layer is composed primarily of a material obtained by mixing under applied heat a specific resin composition and the cover is formed primarily of polyurethane. And, the number of dimples and the trajectory volume TVT are set within specific ranges. The golf ball of the invention has an excellent flight performance, feel, controllability and scuff resistance.

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Chichibu, Japan

Junji Umezawa