Golf ball

Abstract

A golf ball 2 includes a spherical core 4, an inner mid layer 6 positioned outside the core 4, an outer mid layer 8 positioned outside the inner mid layer 6, a reinforcing layer 10 positioned outside the outer mid layer 8, and a cover 12 positioned outside the reinforcing layer 10. When distances (%) from a central point of the core 4 to nine points and JIS-C hardnesses at the nine points, which nine points are obtained by dividing a region from the central point of the core 4 to a surface of the core 4 at intervals of 12.5% of a radius of the core 4, are plotted in a graph, R² of a linear approximation curve obtained by a least-square method is equal to or greater than 0.95.

Description

[0001]This application claims priority on Patent Application No. 2011-195635 filed in JAPAN on Sep. 8, 2011. The entire contents of this Japanese Patent Application are hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to golf balls. Specifically, the present invention relates to golf balls that include a solid core, an inner mid layer, an outer mid layer, and a cover.[0004]2. Description of the Related Art[0005]Golf players' foremost requirement for golf balls is flight performance. In particular, golf players place importance on flight performance upon a shot with a driver. Flight performance correlates with the resilience performance of a golf ball. When a golf ball having excellent resilience performance is hit, the golf ball flies at a high speed, thereby achieving a large flight distance. Golf balls that include a core having excellent resilience performance are disclosed in JP61-37178, JP2008-212681 ...

AI Technical Summary

Benefits of technology

[0020]In the golf ball according to the present invention, a hardness distribution is appropriate. In the golf ball, the energy loss is low when being hit. The golf ball has excellent resilience performance. When the golf ball is hit with a driver, the spin rate is low. The great resilience performance and the low spin rate achieve a large flight distance. When the golf ball is hit with a short iron, the spin rate is high. The golf ball has excellent controllability.

Problems solved by technology

In a golf ball that achieves a high trajectory by a high spin rate, a flight distance is insufficient.

When a backspin rate is high, the run is short.

However, a golf ball having a low spin rate has inferior controllability.

The core has a high energy loss when being hit.

This hardness distribution impairs resilience performance.

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