Patent ID: 7294068

Claim:
A multi-piece solid golf ball, comprising a solid core, an envelope layer that encloses the solid core, an intermediate layer that encloses the envelope layer, and a cover that encloses the intermediate layer and has a plurality of dimples on a surface thereof, wherein the solid core has a diameter of 34.0 to 41.0 mm, a center hardness expressed as the Shore D hardness of 15 to 45, a surface hardness expressed as the Shore D hardness of 40 to 63, and a hardness difference between the center and surface, expressed in Shore D hardness units, of 10 to 40; the envelope layer has a thickness of 0.2 to 1.2 mm and the material of which it is made has a Shore D hardness of 45 to 65; the intermediate layer has a thickness of 0.5 to 1.5 mm, the material of which it is made has a Shore D hardness of 55 to 75, and the intermediate layer is formed so as to be harder than the envelope layer and the cover; the cover has a thickness of 0.6 to 1.5 mm and the material of which it is made has a Shore D hardness of 30 to 60; and the combined thickness of the envelope layer, intermediate layer and cover is from 1.5 to 3.5 mm, wherein the envelope layer and intermediate layer are made primarily of a thermoplastic resin selected from among ionomer resins, polyester elastomers, polyamide elastomers, polyurethanes, and mixtures thereof.