Multi-piece solid golf ball

Abstract

A golf ball is provided that achieves a satisfactory distance on full shots with an iron, is superior in the short game, and has a good feel at impact and a good durability. The golf ball has a core formed of a rubber composition as one or more layer, an envelope layer formed of a resin material as one or more layer, an intermediate layer formed of a resin material as one layer, and a cover formed of a resin material as one layer having a thickness of not more than 1.0 mm. The layers of the ball have Shore C hardnesses at the respective surfaces thereof which together satisfy certain conditions, and the core and the ball have respective deflections which satisfy certain other conditions.

1 . A multi-piece solid golf ball comprising a core, an envelope layer, an intermediate layer and a cover, wherein the core is formed of a rubber composition as one or more layer; the envelope layer is formed of a resin material as one or more layer; the intermediate layer is formed of a resin material as one layer; the cover is formed of a resin material as one layer having a thickness of not more than 1.0 mm; the Shore C hardness at a surface of the core, the Shore C hardness at a surface of the sphere obtained by encasing the core with the envelope layer (envelope layer-encased sphere), the Shore C hardness at a surface of the sphere obtained by encasing the envelope layer-encased sphere with the intermediate layer intermediate layer-encased sphere) and the Shore C hardness at a surface of the ball together satisfy the conditions (Shore C hardness at surface of envelope layer-encased sphere)>(Shore C hardness at core surface) and (Shore C hardness at surface of intermediate layer-encased sphere)>(Shore C hardness at ball surface); and, letting C be the deflection of the core in millimeters when compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) and B be the deflection of the ball in millimeters when compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf), B≥3.0 and 2.5≤C−B≤4.3. 
     
     
         2 . The golf ball of  claim 1 , wherein the Shore C hardness at the surface of the envelope layer-encased sphere and the Shore C hardness at the surface of the intermediate layer-encased sphere together satisfy the condition:
   (Shore  C  hardness at surface of intermediate layer-encased sphere)>Shore  C  hardness at surface of envelope layer-encased sphere).   
     
     
         3 . The golf ball of  claim 1 , wherein the layers have respective thicknesses which together satisfy the condition:
   (cover thickness)<(intermediate layer thickness)≤(total thickness of envelope layer).
   
     
     
         4 . The golf ball of  claim 1 , wherein the layers have respective thicknesses which together satisfy the condition:
   (total thickness of envelope layer)/(cover thickness+intermediate layer thickness)≥1.0.
   
     
     
         5 . The golf ball of  claim 1 , wherein the ball has an initial velocity of at least 76.8 m/s. 
     
     
         6 . The golf ball of  claim 1 , wherein the core has a diameter and the ball has a diameter which together satisfy the condition:
   0.65≤(core diameter)/(ball diameter)≤0.80.
   
     
     
         7 . The golf ball of  claim 1 , wherein the core has an internal hardness which satisfies the condition:
   ( Cs−Cm )/( Cm−Cc )≥1.1,
   
       where Cc is the Shore C hardness at a center of the core, Cs is the Shore C hardness at the core surface, and Cm is the Shore C hardness at the midpoint between the core surface and the core center. 
     
     
         8 . The golf ball of  claim 1 , wherein the envelope layer is formed of at least two layers that include an inner envelope layer and an outer envelope layer. 
     
     
         9 . The golf ball of  claim 8 , wherein the Shore C hardnesses at the surfaces of the respective layers satisfy the condition:
   (Shore  C  hardness at ball surface)<(Shore  C  hardness at surface of intermediate layer-encased sphere)>(Shore  C  hardness at surface of outer envelope layer-encased sphere)≥(Shore  C  hardness at surface of inner envelope layer-encased sphere)>(Shore  C  hardness at core surface).
   
     
     
         10 . The golf ball of  claim 8  which satisfies the condition:
   1.0≤( OE vh+IE vh )/Core  vh≤ 2.3,
 
 
       where Core vh is the product of the core volume (mm 3 ) multiplied by the Shore C hardness Cm at the midpoint between the core surface and the core center, IE vh is the product of the inner envelope layer volume (mm 3 ) multiplied by the Shore C hardness at the surface of the inner envelope layer-encased sphere, and OE vh is the product of the outer envelope layer volume (mm 3 ) multiplied by the Shore C hardness at the surface of the outer envelope layer-encased sphere.