US 11,654,335 B2
Multi-piece solid golf ball
Hideo Watanabe, Saitamaken (JP); and Masanobu Kuwahara, Saitamaken (JP)
Assigned to Bridgestone Sports Co., Ltd., Tokyo (JP)
Filed by Bridgestone Sports Co., Ltd., Tokyo (JP)
Filed on Oct. 13, 2021, as Appl. No. 17/500,546.
Claims priority of application No. JP2020-188080 (JP), filed on Nov. 11, 2020.
Prior Publication US 2022/0143472 A1, May 12, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. A63B 37/06 (2006.01); A63B 37/00 (2006.01)
CPC A63B 37/00922 (2020.08) [A63B 37/009 (2013.01); A63B 37/0043 (2013.01); A63B 37/0063 (2013.01); A63B 37/0064 (2013.01); A63B 37/0076 (2013.01); A63B 37/0087 (2013.01); A63B 37/0096 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A multi-piece solid golf ball comprising a core, an envelope layer, an intermediate layer and a cover, the core being formed of a rubber composition as one layer, the envelope layer being formed of a resin material as one or more layers and the intermediate layer and cover each independently being formed of a resin material as a single layer,
wherein
the core has a surface hardness and a center hardness on the Shore C hardness scale with a difference therebetween of at least 20;
the resin material making up the intermediate layer contains a high-acid ionomer;
the center hardness of the core, surface hardness of the sphere obtained by encasing the core with the envelope layer (envelope layer-encased sphere) and surface hardness of the sphere obtained by encasing the envelope layer-encased sphere with the intermediate layer (intermediate layer-encased sphere) have Shore C hardness relationships therebetween which satisfy the following conditions:
surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere, and  (1)
(surface hardness of intermediate layer-encased sphere)−(center hardness of core)≥40;  (2)
and the ball has a deflection when compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) which is at least 2.7 mm, and
wherein the core has a diameter of from 35.1 to 41.3 mm, and
the core has a hardness profile in which, letting Cc be the Shore C hardness at the core center, Cm be the Shore C hardness at a midpoint M between the core center and the core surface, Cm−2, Cm−4 and Cm−6 be the respective Shore C hardnesses at positions 2 mm, 4 mm and 6 mm inward from the midpoint M, Cm+2, Cm+4 and Cm+6 be the respective Shore C hardnesses at positions 2 mm, 4 mm and 6 mm outward from the midpoint M and Cs be the Shore C hardness at the core surface, and defining the surface areas A to F as follows
surface area A: 1/2×2×(Cm−4−Cm−6)
surface area B: 1/2×2×(Cm−2−Cm−4)
surface area C: 1/2×2×(Cm−Cm−2)
surface area D: 1/2×2×(Cm+2−Cm)
surface area E: 1/2×2×(Cm+4−Cm+2)
surface area F: 1/2×2×(Cm+6−Cm+4),
(surface area E+surface area F)−(surface area A+surface area B) has a value of 2.0 or more.