US2026097268A1PendingUtilityA1

Multi-piece solid golf ball

Assignee: BRIDGESTONE SPORTS CO LTDPriority: Oct 9, 2024Filed: Oct 3, 2025Published: Apr 9, 2026
Est. expiryOct 9, 2044(~18.2 yrs left)· nominal 20-yr term from priority
A63B 37/0089A63B 37/0096A63B 37/009A63B 37/0051A63B 37/00215A63B 37/0063
75
PatentIndex Score
0
Cited by
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Claims

Abstract

Provided is a golf ball including a core, an intermediate layer, a cover, and dimples, in which letting a Shore C hardness of a core surface be H100, Shore C hardnesses at an 87.5% outer position, a 75% outer position, a 62.5% outer position, a 50% outer position, a 37.5% outer position, a 25% outer position, and a 12.5% outer position of a core radius from a core center be H87.5, H75, H62.5, H50, H37.5, H25, and H12.5, respectively, and a Shore C hardness at the core center be H0, the following two conditions are satisfied: 0 ≤ ( H ⁢ 6 2.5 - H ⁢ 50 ) < ( H ⁢ 100 - H 87.5 ) < ( H ⁢ 8 7.5 - H ⁢ 75 ) < ( H ⁢ 75 - H 62.5 ) ≤ 7. and ⁢ ( H ⁢ 100 - H ⁢ 50 ) / ( H ⁢ 50 - H ⁢ 0 ) ≥ 2 . 7 and the golf ball has a specific dimple volume occupancy ratio.

Claims

exact text as granted — not AI-modified
1 . A multi-piece solid golf ball comprising a core, an intermediate layer, and a cover, wherein a large number of dimples are formed on an outside surface of the cover, and in a hardness profile of the core, letting a Shore C hardness at a core surface be H100, a Shore C hardness at a position outside by 87.5% of a core radius from a core center be H87.5, a Shore C hardness at a position outside by 75% of the core radius from the core center be H75, a Shore C hardness at a position outside by 62.5% of the core radius from the core center be H62.5, a Shore C hardness at a position outside by 50% of the core radius from the core center be H50, a Shore C hardness at a position outside by 37.5% of the core radius from the core center be H37.5, a Shore C hardness at a position outside by 25% of the core radius from the core center be H25, a Shore C hardness at a position outside by 12.5% of the core radius from the core center be H12.5, and the Shore C hardness at the core center be H0, the following two conditions are satisfied: 
       
         
           
             
               
                 0 
                 ≤ 
                 
                   ( 
                   
                     
                       H 
                       ⁢ 
                       6 
                       2.5 
                     
                     - 
                     
                       H 
                       ⁢ 
                       50 
                     
                   
                   ) 
                 
                 < 
                 
                   ( 
                   
                     
                       H 
                       ⁢ 
                       100 
                     
                     - 
                     
                       H 
                         
                       87.5 
                     
                   
                   ) 
                 
                 < 
                 
                   ( 
                   
                     
                       H 
                       ⁢ 
                       8 
                       7.5 
                     
                     - 
                     
                       H 
                       ⁢ 
                       75 
                     
                   
                   ) 
                 
                 < 
                 
                   ( 
                   
                     
                       H 
                       ⁢ 
                       75 
                     
                     - 
                     
                       H 
                         
                       62.5 
                     
                   
                   ) 
                 
                 ≤ 
                 7. 
               
               , 
               and 
             
           
         
         
           
             
               
                 
                   ( 
                   
                     
                       H 
                       ⁢ 
                       100 
                     
                     - 
                     
                       H 
                       ⁢ 
                       50 
                     
                   
                   ) 
                 
                 / 
                 
                   ( 
                   
                     
                       H 
                       ⁢ 
                       50 
                     
                     - 
                     
                       H 
                       ⁢ 
                       0 
                     
                   
                   ) 
                 
               
               ≥ 
               
                 2 
                 . 
                 7 
               
             
           
         
         and the dimple has a volume occupancy ratio VR of from 0.75 to 0.89%. 
       
     
     
         2 . The multi-piece solid golf ball of  claim 1 , wherein when a ratio CL1/CD1 of a lift coefficient CL1 at a Reynolds number of 218,000 and a spin rate of 2,300 rpm to a drag coefficient CD1 is denoted by A1, and a ratio CL2/CD2 of a lift coefficient CL2 at a Reynolds number of 158,000 and a spin rate of 3,100 rpm to a drag coefficient CD2 is denoted by A2, the following two conditions are satisfied: 
       
         
           
             
               
                 0.53 
                 ≤ 
                 
                   A 
                   ⁢ 
                   1 
                 
                 ≤ 
                 
                   
                     0 
                     . 
                     6 
                   
                   ⁢ 
                   00 
                 
               
               , 
               and 
             
           
         
         
           
             
               0.695 
               ≤ 
               
                 A 
                   
                 2. 
               
             
           
         
       
     
     
         3 . The multi-piece solid golf ball of  claim 1 , wherein the following condition is satisfied: 
       
         
           
             
               
                 
                   ( 
                   
                     
                       H 
                       ⁢ 
                       100 
                     
                     - 
                     
                       H 
                         
                       87.5 
                     
                   
                   ) 
                 
                 / 
                 
                   ( 
                   
                     
                       H 
                         
                       87.5 
                     
                     - 
                     
                       H 
                       ⁢ 
                       75 
                     
                   
                   ) 
                 
               
               ≤ 
               
                 
                   0 
                   . 
                   9 
                 
                 ⁢ 
                 
                   0 
                   . 
                 
               
             
           
         
       
     
     
         4 . The multi-piece solid golf ball of  claim 1 , wherein values of the following eight conditions are all positive values: 
       
         
           
             
               
                 
                   
                     
                       
                         H 
                         ⁢ 
                         100 
                       
                       - 
                       
                         H 
                           
                         87.5 
                       
                     
                     , 
                   
                 
               
               
                 
                   
                     
                       
                         H 
                           
                         87.5 
                       
                       - 
                       
                         H 
                         ⁢ 
                         75 
                       
                     
                     , 
                   
                 
               
               
                 
                   
                     
                       
                         H 
                         ⁢ 
                         75 
                       
                       - 
                       
                         H 
                           
                         62.5 
                       
                     
                     , 
                   
                 
               
               
                 
                   
                     
                       
                         H 
                           
                         62.5 
                       
                       - 
                       
                         H 
                         ⁢ 
                         50 
                       
                     
                     , 
                   
                 
               
               
                 
                   
                     
                       
                         H 
                         ⁢ 
                         50 
                       
                       - 
                       
                         H 
                           
                         37.5 
                       
                     
                     , 
                   
                 
               
               
                 
                   
                     
                       
                         H 
                           
                         37.5 
                       
                       - 
                       
                         H 
                         ⁢ 
                         25 
                       
                     
                     , 
                   
                 
               
               
                 
                   
                     
                       
                         H 
                         ⁢ 
                         25 
                       
                       - 
                       
                         H 
                           
                         12.5 
                       
                     
                     , 
                     and 
                   
                 
               
               
                 
                   
                     
                       H 
                         
                       12.5 
                     
                     - 
                     
                       H 
                         
                       0. 
                     
                   
                 
               
             
           
         
       
     
     
         5 . The multi-piece solid golf ball of  claim 1 , wherein the core is formed of a rubber composition including the following components (a) to (e):
 (a) a base rubber,   (b) an α,β-unsaturated carboxylic acid and/or a metal salt thereof as a co-crosslinking agent,   (c) an organic peroxide,   (d) water or a moisture-providing agent, and   (e) a hindered phenol-based antioxidant having a substituent having a thioether structure, the moisture-providing agent being a substance that contains a water component other than free water in a structure thereof and desorbs moisture by heating, or a substance that releases a water component by thermal decomposition by heating, a compounding amount of the component (e) being at least 0.2 parts by weight per 100 parts by weight of the component (a).   
     
     
         6 . The multi-piece solid golf ball of  claim 5 , wherein the hindered phenol-based antioxidant serving as component (e) has a chemical structure having at least one methyl group at an ortho position. 
     
     
         7 . The multi-piece solid golf ball of  claim 5 , wherein the hindered phenol-based antioxidant serving as component (e) has at least two substituents having a thioether structure. 
     
     
         8 . The multi-piece solid golf ball of  claim 1 , wherein a deflection when the core is compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) is not more than 3.8 mm. 
     
     
         9 . The multi-piece solid golf ball of  claim 1 , wherein when a deflection when the core is compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) is A (mm), and a deflection when the golf ball is compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) is B (mm), a value of A−B is less than 1.0 mm. 
     
     
         10 . The multi-piece solid golf ball of  claim 1 , wherein a relationship between a surface hardness of a sphere (intermediate layer-encased sphere) obtained by encasing the core with the intermediate layer and a surface hardness of the ball satisfies the following condition: 
       
         
           
             
               
                 
                   ( 
                   
                     
                       Shore 
                       ⁢ 
                           
                       D 
                       ⁢ 
                           
                       hardness 
                       ⁢ 
                           
                       of 
                       ⁢ 
                           
                       surface 
                       ⁢ 
                           
                       of 
                       ⁢ 
                           
                       intermediate 
                       ⁢ 
                           
                       layer 
                     
                     - 
                     
                       encased 
                       ⁢ 
                           
                       sphere 
                     
                   
                   ) 
                 
                 - 
                 
                   ( 
                   
                     Shore 
                     ⁢ 
                         
                     D 
                     ⁢ 
                         
                     hardness 
                     ⁢ 
                         
                     of 
                     ⁢ 
                         
                     surface 
                     ⁢ 
                         
                     of 
                     ⁢ 
                         
                     ball 
                   
                   ) 
                 
               
               ≥ 
               3.

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