US 11,654,334 B2
Multi-piece solid golf ball
Hideo Watanabe, Saitamaken (JP)
Assigned to BRIDGESTONE SPORTS CO., LTD., Tokyo (JP)
Filed by BRIDGESTONE SPORTS CO., LTD., Tokyo (JP)
Filed on Feb. 25, 2022, as Appl. No. 17/680,470.
Application 17/680,470 is a continuation in part of application No. 17/216,790, filed on Mar. 30, 2021, granted, now 11,291,888.
Claims priority of application No. 2020-081966 (JP), filed on May 7, 2020.
Prior Publication US 2022/0176205 A1, Jun. 9, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. A63B 37/06 (2006.01); A63B 37/00 (2006.01)
CPC A63B 37/0076 (2013.01) [A63B 37/008 (2013.01); A63B 37/0033 (2013.01); A63B 37/0045 (2013.01); A63B 37/0063 (2013.01); A63B 37/0064 (2013.01); A63B 37/00922 (2020.08)] 11 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 or more layer, the envelope layer being formed of a resin material as one or more layer and the intermediate layer and the cover each being formed of a resin material as a single layer,
wherein
the core has a diameter of from 35.1 to 41.3 mm;
the ratio (core diameter)/(ball diameter) has a value of at least 0.825;
the core has a hardness profile in which, letting Cc be the Shore C hardness at a center of the core, Cc+4 be the Shore C hardness 4 mm outward from the core center, Cm be the Shore C hardness at a midpoint M between the core center and a surface of the core, Cm−4 and Cm+4 be the respective Shore C hardnesses at positions 4.0 mm inward and 4.0 mm outward from the midpoint M, Cs be the Shore C hardness at the core surface and Cs−4 be the Shore C hardness 4 mm inward from the core surface and defining the surface areas A to D as follows
surface area A: ½×4×(Cc+4−Cc)
surface area B: ½×4×(Cm−Cm−4)
surface area C: ½×4×(Cm+4−Cm)
surface area D: ½×4×(Cs−Cs−4),
the ratio (surface area C)/(surface area A) has a value of 0.5 or more and Cs−Cc has a value of 20 or more;
the center hardness of the core, surface hardness of the core, surface hardness of the sphere obtained by encasing the core with the envelope layer (envelope layer-encased sphere), surface hardness of the sphere obtained by encasing the envelope layer-encased sphere with the intermediate layer (intermediate layer-encased sphere) and surface hardness of the ball have Shore C hardness relationships therebetween which satisfy the following conditions:
core surface hardness<surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere>ball surface hardness, and  (1)
(surface hardness of envelope layer-encased sphere)−(center hardness of core)≥28;  (2)
and the envelope layer, intermediate layer and cover have respective thicknesses which satisfy the following condition:
cover thickness<intermediate layer thickness  (3)
cover thickness<envelope layer thickness  (4)
envelope layer thickness≥0.8 mm  (5).