US 11,911,665 B2
Golf ball
Hideo Watanabe, Saitamaken (JP); and Atsuki Kasashima, Saitamaken (JP)
Assigned to BRIDGESTONE SPORTS CO., LTD., Tokyo (JP)
Filed by BRIDGESTONE SPORTS CO., LTD., Tokyo (JP)
Filed on May 13, 2022, as Appl. No. 17/743,574.
Claims priority of application No. 2021-087080 (JP), filed on May 24, 2021.
Prior Publication US 2022/0370859 A1, Nov. 24, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. A63B 37/06 (2006.01); A63B 37/00 (2006.01)
CPC A63B 37/0074 (2013.01) [A63B 37/0021 (2013.01); A63B 37/00215 (2020.08); A63B 37/0063 (2013.01); A63B 37/0064 (2013.01); A63B 37/0065 (2013.01); A63B 37/008 (2013.01); A63B 37/0087 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A golf ball comprising a core and a cover, which cover has a plurality of dimples on a surface thereof, wherein the cover is formed primarily of polyurethane and the dimples thereon have a volume occupancy ratio VR within the range of 0.80 to 0.92%, the ball has a diameter of at least 42.8 mm and, in an impact test carried out by hitting the ball with a driver at a head speed of 40 m/s, the sum t1+t2 of the time t1 required from initial contact by the driver with the ball for deformation of the ball to reach a maximum and the time t2 required from the state of maximum ball deformation for the ball and the driver to separate is 660 μsec or less,
wherein the core has a diameter of at least 37.0 mm and a hardness profile in which, letting Cc be the Shore C hardness at a center of the core, Cs be the Shore C hardness at a surface of the core, Cm be the Shore C hardness at a midpoint M between the core center and the core surface, Cm−2, Cm−4, Cm−6 and Cm−8 be the respective Shore C hardnesses at positions 2 mm, 4 mm, 6 mm and 8 mm inward from the midpoint M and 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 defining surface areas X and A to F as follows
surface area X: ½×2×(Cm−6-Cm−8)
surface area A: ½×2×(Cm−4-Cm−6)
surface area B: ½×2×(Cm−2-Cm−4)
surface area C: ½×2×(Cm-Cm−2)
surface area D: ½×2×(Cm+2-Cm)
surface area E: ½×2×(Cm+4-Cm+2)
surface area F: ½×2×(Cm+6-Cm+4),
the core satisfies the condition:
(surface area D+surface area E+surface area F)−(surface area A+surface area B+surface area C)>0, and wherein an intermediate layer made of a resin material is formed between the core and the cover, and the sphere obtained by encasing the core with the intermediate layer (intermediate layer-encased sphere) and the ball satisfy the following surface hardness (Shore C hardness) relationship;
9≤(surface hardness of intermediate layer-encased sphere)−(surface hardness of ball)≤15, and the surface hardness of the intermediate layer-encased sphere is from 70 to 78, expressed on the Shore D hardness scale.