Golf ball

• US 20030190968A1
• Filed: 03/21/2003
• Published: 10/09/2003
• Est. Priority Date: 03/29/2002
• Status: Active Grant

• Current Assignee: Bridgestone Sports Co Limited (Bridgestone Corporation)
• Original Assignee: Bridgestone Sports Co Limited (Bridgestone Corporation)
• Inventors: Kasashima, Atsuki
• Granted Patent: US 7,018,308 B2
• Time in Patent Office: Days
• US Class Current: 473/131
• CPC Class Codes: A63B 37/0004 Surface depressions or protrusions
• CPC Class Codes: A63B 37/0012 Dimple profile, i.e. cross-sectional view
• CPC Class Codes: A63B 37/0016 Specified individual dimple volume
• CPC Class Codes: A63B 37/0019 Specified dimple depth
• CPC Class Codes: A63B 37/002 Specified dimple diameter
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0039 characterised by the material
• CPC Class Codes: A63B 37/0043 Hardness
• CPC Class Codes: A63B 37/0045 Thickness
• CPC Class Codes: A63B 37/0075 Three piece balls, i.e. cover, intermediate layer and core
• CPC Class Codes: A63B 37/0084 Initial velocity
• CPC Class Codes: A63B 37/0089 Coefficient of drag
• CPC Class Codes: A63B 37/009 Coefficient of lift
• CPC Class Codes: A63B 37/0096 Spin rate

Abstract

A golf ball includes a multiplicity of dimples on its outer surface. At least one or more of the multiplicity of dimples are each configured to have a convex bottom portion formed by a circular-arc defined by a center positioned inside the ball and a curvature radius “r” mm smaller than a radius “R” mm of the ball but larger than a value (R−0.5) mm. The golf ball specified such that the shapes of the dimples are optimized as described above exhibits high flight characteristics.

Claims

1. A golf ball comprising a multiplicity of dimples on its outer surface, wherein at least one or more of said multiplicity of dimples are each configured to have a convex bottom portion formed by a circular-arc defined by a center positioned inside said ball and a curvature radius “

r”

mm smaller than a radius “

R”

mm of said ball but larger than a value (R-0.5) mm.

2. A golf ball according to claim 1, wherein said dimple having said convex bottom portion is formed into a circular shape in a plan view.

3. A golf ball according to claim 1, wherein said dimple having said convex bottom portion is formed into a non-circular shape in a plan view.

4. A golf ball according to claim 1, wherein a ratio CL/CD of a lift coefficient CL to a drag coefficient CD of said ball during flight thereof is in a range of 0.676 to 0.796 under a condition with a Reynolds number of 200,000 and a spin rate of 2,700 rpm, in a range of 0.813 to 0.933 under a condition with a Reynolds number of 12,000 and a spin rate of 2,400 rpm, and in a range of 0.856 to 0.976 under a condition with a Reynolds number of 80,000 and a spin rate of 2,000 rpm.