In a multi-piece solid golf ball having a core, a cover and an intermediate layer therebetween, the core, an intermediate layer-encased sphere and the ball have surface hardnesses which satisfy a specific relationship, and the intermediate layer and the cover have thicknesses which satisfy a specific relationship. Also, the core has a hardness profile in which the hardnesses at the core surface, core center, a position 5 mm from the core center, and a position midway between the surface and center of the core satisfy specific relationships. This golf ball, when used by mid- and high-level amateurs, enables the golfer to maintain an adequate distance on shots with a driver and achieve a good distance on iron shots, has a good spin performance on approach shots and has a good feel on impact. In addition, the ball has an excellent scuff resistance when struck with a grooved wedge.

In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer, and a cover with a plurality of dimples thereon, the core is a two-layer core consisting of an inner core layer and an outer core layer each formed primarily of a base rubber, the envelope layer, the intermediate layer and the cover layer are each composed of at least one layer and formed primarily of a synthetic resin material, and the initial velocities and surface hardnesses of the core, the envelope layer-encased sphere and the intermediate layer-encased sphere are designed within specific ranges. This golf ball satisfies at a very high level the flight and control performances expected for use by professional golfers and skilled amateurs, has the ability to move forward on a straight path particularly on full shots, and also has an excellent scuff resistance.

A golf ball having a core, a cover and at least one intermediate layer therebetween satisfies specific conditions concerning the relative surface hardnesses of the core, the intermediate layer-encased sphere and the ball, and has a specific core hardness profile. Also, the value V/H, where V is the initial velocity of the ball and H is the deflection of the ball under specific loading, is set within a specific range. The ball has a construction which, when used by the ordinary amateur golfer, reduces the spin rate on full shots, enabling good distances to be obtained both on shots with a driver and on shots with an iron. The ball also has a soft yet crisp feel at impact.

The present invention is directed to multi-layer golf balls including a layer formed from a composition comprising a relatively soft or low modulus HNP, a layer formed from a composition comprising a relatively hard or high modulus HNP, an inner cover layer formed from a thermoplastic composition, and an outer cover layer.

In a multi-piece solid golf ball having a rubber two-layer core consisting of an inner layer and an outer layer, a cover, and at least one intermediate layer therebetween, the inner core layer has a diameter of at least 30 mm, the difference in JIS-C hardness between the center of the inner core layer and the surface of the outer core layer is at least 25, the ball satisfies the relationship A/B1.5, where A and B are the deflections of, respectively, the inner core layer and the two-layer core when compressed under specific loading conditions, and the intermediate layer has a higher material hardness than the cover. This ball enables mid- to high-level golfers both to achieve even longer distances and to maintain the spin performance on approach shots at a high level.

The present invention provides a multi-piece solid golf ball including a core, a surrounding layer, an intermediate layer, and a cover, in which a large number of dimples are formed on an outside surface of the cover, the core is formed of a single layer or a plurality of layers of a rubber composition, the surrounding layer is formed of a single layer or a plurality of layers of a resin composition, the intermediate layer and the cover are both formed of a single layer of a resin composition, and a relationship between an initial velocity of an intermediate layer-encased sphere and an initial velocity of the ball satisfies the following condition:

(initial velocity of ball)<(initial velocity of intermediate layer-encased sphere).

Further, a deflection of the ball under a predetermined load is optimized, and a lift coefficient and a drag coefficient at a predetermined Reynolds number and spin rate of the dimples are set within a predetermined range.

A golf ball includes a core, an intermediate layer, and a cover, in which an initial velocity is not more than 76.0 m/s, a deflection when the ball is compressed under a specific load is at least 2.8 mm, and letting a value of (initial velocity of coreweight of core) be Ciw, a value of [(initial velocity of intermediate layer-encased sphereinitial velocity of core)(weight of intermediate layer-encased sphereweight of core)] be Miw, and a value of [(initial velocity of ballinitial velocity of intermediate layer-encased sphere)(weight of ballweight of intermediate layer-encased sphere)] be CViw, the condition is of Ciw+Miw+CViw2,550 is satisfied, thereby to be capable of making a distance for reducing a distance on shots with a driver and an iron by average hitters smaller.

Synergistic pairing of golf clubs with golf balls both with improved aerodynamic properties to help improve the performance of both. In an example, a golf club has a golf club head; a grip; and a shaft having a tip end and a butt end. The golf club head is coupled to the shaft at the tip end, and the grip is coupled to the shaft at the butt end. The golf ball has at least a core and a cover having a plurality of dimples arranged in a dimple pattern.

In a golf ball having a core, a cover and at least one intermediate layer formed therebetween, the core, intermediate layer and cover have respective specific gravities with a standard deviation of not more than 0.07 or less, the cover has a material hardness on the Shore D hardness scale of 52 or less, 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 2.8 mm or less. The amount of deviation in the ball center of gravity is exceedingly small, increasing the straightness with which the ball rolls on putts with a putter.

Multi-layered golf ball core sub-assemblies and the resulting golf balls are provided. The core structure includes an inner core (center) comprising a foam composition, preferably foamed polyurethane. The intermediate and outer core layers are preferably formed from foamed and non-foamed thermoset compositions. For example, the intermediate core can be formed from a thermoset rubber so there are adjoining foam core layers (inner and intermediate) and the outer core layer can be formed from a non-foamed thermoset rubber. The core layers have different hardness and specific gravity levels. The core assembly preferably has a positive hardness gradient extending across the entire assembly. The core structure and resulting ball have relatively good resiliency.