Multi-layer golf ball
View Patent ↗A multi-layer golf ball includes a core, and intermediate layer, and a cover. The core has an outer surface that includes a plurality of depressions extending from a spherical land portion. Each depression has a maximum depth relative to the spherical land portion of between 0.15 mm and 2.0 mm. The intermediate layer surrounds the core and has a radially inward surface that is flush with the outer surface of the core. The cover layer surrounds the intermediate layer and defines an outermost portion of ball.
1. A multi-layer golf ball comprising:
a core defining the innermost portion of the golf ball, the core having an outer surface that includes:
a plurality of circular depressions extending radially inward from and symmetrically disposed about a spherical land portion;
wherein each of the depressions has a maximum depth relative to the spherical land portion of between 0.2 mm and 0.6 mm; and
wherein the spherical land portion has a diameter of between 24 mm and 32 mm;
an intermediate layer surrounding the core and having a radially inward surface that is bonded to the outer surface of the core across the entire outer surface, the intermediate layer having a minimum radial thickness of between 4 mm and 9 mm; and
a cover layer surrounding the intermediate layer and defining an outermost portion of the golf ball.
2. The golf ball of claim 1 , wherein the core is formed from an ionomeric material having a hardness measured on the JIS-C scale of between 34 and 70, and wherein the intermediate layer is formed from a rubber material having a hardness measured on the Shore D scale of between 56 and 64.
3. The golf ball of claim 1 , wherein each of the depressions has: a width measured at the spherical land portion; and a width/maximum depth ratio of between 2 and 8.
4. The golf ball of claim 1 , wherein the cover layer includes one or more of an ionomer resin, a polyethylene, and a polyester resin.
5. The golf ball of claim 1 , wherein the cover layer is formed from a thermoplastic material having a hardness measured on the Shore-D scale of up to about 72.
6. The golf ball of claim 5 , wherein the thermoplastic material is a thermoplastic polyurethane having a flexural modulus of up to about 1000 psi.
7. The golf ball of claim 1 , wherein the intermediate layer is a first intermediate layer, the golf ball further comprising a second intermediate layer disposed between the first intermediate layer and the cover layer.
8. The golf ball of claim 7 , wherein the second intermediate layer has a hardness measured on the Shore-D scale of greater than 63 and greater than a hardness of the cover layer.
9. The golf ball of claim 1 , wherein the core has a 10-130 kg compression deformation of between 3.5 mm and 5.5 mm;
wherein the core and the intermediate layer define an intermediate ball; and
wherein the intermediate ball has a 10-130 kg compression deformation of between 2.7 and 5.5 mm, and less than the 10-130 kg compression deformation of the core.
10. The golf ball of claim 1 , wherein the intermediate layer is bonded to the core through an adhesive layer.
11. The golf ball of claim 10 , wherein the adhesive layer includes an ethylene vinyl acetate copolymer-based adhesive.
12. The golf ball of claim 1 , wherein the core includes an ionomeric material that has a flexural modulus of less than 10,000 psi.
13. The golf ball of claim 1 , wherein the intermediate layer is formed from a rubber material that includes:
a main rubber containing a polybutadiene;
an unsaturated carboxylic acid or a metal salt thereof, or both; and
an organic peroxide.
14. The golf ball of claim 1 , wherein the plurality of depressions includes between 50 and 80 depressions.
15. A multi-layer golf ball comprising:
a single-piece core defining the innermost portion of the golf ball, the core being formed, in whole or in part, from an ionomeric material having a hardness measured on the JIS-C scale of between about 34 and 70, the core having an outer surface that includes:
between about 50 and 80 circular depressions extending radially inward from and symmetrically disposed about a spherical land portion;
wherein each depression has a maximum depth relative to the spherical land portion of between 0.2 and 0.6 mm; and
wherein the spherical land portion has a diameter of between about 24 mm and 32 mm;
an intermediate layer formed, in whole or in part, from a rubber material having a hardness measured on the Shore D scale of between 56 and 64, the intermediate layer surrounding the core and having a radially inward surface that is bonded to the outer surface of the core across the entire outer surface, the intermediate layer having a minimum radial thickness of between about 4 mm and 9 mm; and
a cover layer surrounding the intermediate layer and defining an outermost portion of ball.
16. The golf ball of claim 15 , wherein each of the depressions has: a width measured at the spherical land portion; and a width/maximum depth ratio of between 2 and 8.
17. The golf ball of claim 15 , wherein the cover layer includes one or more of an ionomer resin, a polyethylene, and a polyester resin.
18. The golf ball of claim 15 , wherein the cover layer is formed from a thermoplastic material having a hardness measured on the Shore-D scale of up to about 72.
19. The golf ball of claim 18 , wherein the thermoplastic material is a thermoplastic polyurethane having a flexural modulus of up to about 1000 psi.
20. The golf ball of claim 15 , wherein the intermediate layer is a first intermediate layer, the golf ball further comprising a second intermediate layer disposed between the first intermediate layer and the cover layer.
21. The golf ball of claim 20 , wherein the second intermediate layer has a hardness measured on the Shore-D scale of greater than 63 and greater than a hardness of the cover layer.
22. The golf ball of claim 15 , wherein the core has a 10-130 kg compression deformation of between 3.5 mm and 5.5 mm;
wherein the core and the intermediate layer define an intermediate ball; and
wherein the intermediate ball has a 10-130 kg compression deformation of between 2.7 and 5.5 mm, and less than the 10-130 kg compression deformation of the core.
23. The golf ball of claim 15 , wherein the intermediate layer is bonded to the core through an adhesive layer.
24. The golf ball of claim 23 , wherein the adhesive layer includes an ethylene vinyl acetate copolymer-based adhesive.
25. The golf ball of claim 15 , wherein the rubber material includes:
a main rubber containing a polybutadiene;
an unsaturated carboxylic acid or a metal salt thereof, or both; and
an organic peroxide.
26. A golf ball comprising:
a single-piece core defining an innermost portion of the golf ball, the core having an outer surface that includes a plurality of circular depressions extending radially inward from and symmetrically disposed about a spherical land portion, each of the depressions having a depth relative to the spherical land portion of 0.2 mm to 0.6 mm, the spherical land portion having a diameter of approximately 24 mm to 32 mm;
an intermediate layer surrounding the core and having a radially inward surface that is bonded to the outer surface of the core, the intermediate layer having a radial thickness of approximately 4 mm to 9 mm; and
a cover layer surrounding the intermediate layer and defining an outermost portion of the golf ball, the core having a 10-130 kg compression deformation of approximately 3.5 mm to 5.5 mm,
wherein the intermediate layer and the core collectively define an intermediate ball, the intermediate ball having a 10-130 kg compression deformation of approximately 2.7 mm to 5.5 mm, the 10-130 kg compression deformation of the intermediate ball being less than the 10-130 kg compression deformation of the core.