Multi-piece solid golf ball

Abstract

In a golf ball having a core, envelope layer, intermediate layer and cover, the (core diameter) / (ball diameter) value falls within a particular range, the core has a specific hardness profile, and the Shore C hardness relationships among the core center and surface hardnesses and the surface hardnesses of the envelope layer-encased sphere, intermediate layer-encased sphere and ball satisfy the following conditions:(1) core surface hardness<surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere>ball surface hardness,(2) (surface hardness of envelope layer-encased sphere)−(core center hardness)≥28.Also, the intermediate layer and cover have respective thicknesses which satisfy the condition:(3) cover thickness<intermediate layer thickness.This ball enables mid-level and skilled amateur golfers to achieve superior distances on driver shots and on iron shots, and moreover has a soft yet good feel at impact.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 2020-081975 filed in Japan on May 7, 2020, the entire contents of which are hereby incorporated by reference.TECHNICAL FIELD[0002]The present invention relates to a multi-piece solid golf ball composed of four or more layers that include a core, an envelope layer, an intermediate layer and a cover.BACKGROUND ART[0003]Many innovations have been made in designing golf balls with a multilayer construction, and numerous balls that satisfy the needs of not only professional golfers, but also skilled and mid-level amateur golfers, have been developed to date. For example, functional multi-piece solid golf balls in which the surface hardnesses of the respective layers—i.e., the core, envelope layer, intermediate layer and cover (outermost layer)—have been optimized are in wide use. Also, a number of technical disclosures have been published that fo...

AI Technical Summary

Benefits of technology

The patent describes a new golf ball design that has several benefits. It doesn't spin too much on driver shots, which helps the ball go farther. It also has a good feel when hit with a club. This makes it useful for mid-level and skilled golfers. A diagram shows the structure of the ball, and a chart explains how hard the ball is.

Problems solved by technology

That is, these golf balls, even if they are able to retain a good distance on driver (W #1) shots when hit by mid-level to skilled amateur golfers whose head speeds are not as fast as those of professionals, often fall short in terms of their distance on iron shots.

Moreover, with some of these prior-art golf balls, when an attempt is made to obtain a superior distance performance not only on driver shots but also on iron shots, a sufficiently high spin rate on approach shots cannot be achieved, resulting in a ball that does not have a high playability or that has a poor feel at impact on full shots.

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