US2017182371A1PendingUtilityA1

Golf ball

Assignee: DUNLOP SPORTS CO LTDPriority: Dec 24, 2015Filed: Nov 28, 2016Published: Jun 29, 2017

Est. expiryDec 24, 2035(~9.5 yrs left)· nominal 20-yr term from priority

Inventors:Kohei Mimura Kazuya Kamino Kosuke Tachibana

A63B 37/0031A63B 37/0045A63B 37/0076A63B 37/0033A63B 37/0043A63B 37/0017A63B 37/0064A63B 37/008A63B 37/0018A63B 37/004A63B 37/0044A63B 37/0019A63B 37/0063A63B 37/006A63B 37/002A63B 37/0062A63B 37/0092A63B 37/0021A63B 37/0004A63B 37/00622A63B 37/00621

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Claims

Abstract

A golf ball 2 includes an inner core 4 , an outer core 6 , a mid layer 8 , a cover 10 , and dimples 12 . A diameter D1, a volume V1, a hardness H1o at a central point, a boundary inside hardness H1in, and a hardness difference De1 of the inner core 4 ; a volume V2 (mm 3 ) and a hardness difference De2 of the outer core 6 ; a thickness Tm and a hardness Hm of the mid layer 8 ; and a thickness Tc and a hardness Hc of the cover 10 meet the following mathematical formulas. 1.0< V 2/ V 1<7.0 De 2− De 1<0 600<( H 1 o*H 1 in )*( D 1/2)/2<1000 620< Tc*Hc*Hm/Tm <900 The dimples 12 include a plurality of small dimples each having an area of less than 8.0 mm 2 .

Claims

exact text as granted — not AI-modified

What is claimed is: 
     
         1 . A golf ball comprising an inner core, an outer core positioned outside the inner core, a mid layer positioned outside the outer core, and a cover positioned outside the mid layer, wherein
 the golf ball has a plurality of dimples on a surface thereof,   the dimples include a plurality of small dimples each having an area of less than 8.0 mm 2  and a plurality of large dimples each having an area of equal to or greater than 8.0 mm 2 ,   a ratio PS of a sum of the areas of the small dimples relative to a surface area of a phantom sphere of the golf ball is less than 2.0%,   a ratio PL of a sum of the areas of the large dimples relative to the surface area of the phantom sphere is equal to or greater than 79.0%, and   a degree of uniformity G of the areas (mm 2 ) of the large dimples is equal to or less than 1.15.   
     
     
         2 . The golf ball according to  claim 1 , wherein
 a volume V1 (mm 3 ) of the inner core and a volume V2 (mm 3 ) of the outer core meets the following mathematical formula (1),
   1.0&lt; V 2/ V 1&lt;7.0  (1).
 
   
     
     
         3 . The golf ball according to  claim 2 , wherein the golf ball meets the following mathematical formula:
   2.0&lt; V 2/ V 1&lt;6.0.   
     
     
         4 . The golf ball according to  claim 1 , wherein
 a difference De1 between a boundary inside hardness H1in (Shore C) and a hardness H1o (Shore C) at a central point of the inner core; and a difference De2 between a surface hardness H2s (Shore C) and a boundary outside hardness H2out (Shore C) of the outer core meets the following mathematical formula (2),
     De 2− De 1&lt;0  (2).
 
   
     
     
         5 . The golf ball according to  claim 1 , wherein
 a diameter D1 (mm), a hardness H1o (Shore C) at a central point, and a boundary inside hardness H1in (Shore C) meets the following mathematical formula (3),
   600&lt;( H 1 o+H 1 in )*( D 1/2)/2&lt;1000  (3).
 
   
     
     
         6 . The golf ball according to  claim 5 , wherein the golf ball meets the following mathematical formula:
   700&lt;( H 1 o+H 1 in )*( D 1/2)/2&lt;900.   
     
     
         7 . The golf ball according to  claim 1 , wherein
 a thickness Tm (mm) and a hardness Hm (Shore D) of the mid layer; and a thickness Tc (mm) and a hardness Hc (Shore D) of the cover meets the following mathematical formula (4),
   620&lt; Tc*Hc*Hm/Tm&lt; 900  (4).
 
   
     
     
         8 . The golf ball according to  claim 7 , wherein the golf ball meets the following mathematical formula:
   640&lt; Tc*Hc*Hm/Tm&lt; 800.   
     
     
         9 . The golf ball according to  claim 1 , wherein the ratio PS is equal to or greater than 0.7%. 
     
     
         10 . The golf ball according to  claim 1 , wherein a number NS of the small dimples is equal to or greater than 6 but equal to or less than 20. 
     
     
         11 . The golf ball according to  claim 1 , wherein a ratio (NS/N) of a number NS of the small dimples relative to a total number N of the dimples is equal to or greater than 0.01 but equal to or less than 0.07. 
     
     
         12 . The golf ball according to  claim 1 , wherein a depth of a deepest part of each dimple from a surface of the phantom sphere is equal to or greater than 0.10 mm but equal to or less than 0.65 mm. 
     
     
         13 . The golf ball according to  claim 1 , wherein a total volume of the dimples is equal to or greater than 450 mm 3  but equal to or less than 750 mm 3 . 
     
     
         14 . The golf ball according to  claim 1 , wherein the ratio PL is equal to or greater than 79.5%, and the degree of uniformity G is equal to or less than 1.10. 
     
     
         15 . The golf ball according to  claim 14 , wherein the ratio PL is equal to or greater than 80.0%, and the degree of uniformity G is equal to or less than 1.05.

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