Golf Ball Hardness Profile for Distance and Spin Balance

Solution Overview

Problem

Existing golf balls with flexible covers achieve excellent controllability but compromise resilience and flight distance, while those with high resilience impair spin and controllability, failing to meet the diverse performance needs of skilled golfers.

Innovation Solution

A golf ball design featuring a spherical core with specific hardness distributions and a mid layer that balances resilience, spin, and controllability, using a core with an outer hard/inner soft hardness profile and a flexible cover to enhance flight performance and maintain spin control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a flexible cover is used to achieve soft feel at impact, then feel at impact is improved, but resilience performance deteriorates

Engineering Contradiction:

Improvefeel at impactVSAvoidresilience performance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies local quality by creating different hardness zones within the core structure. The core has a first hardness region and a second hardness region with different Shore-C hardness values, allowing the inner portion to provide resilience while the outer portion works with the flexible cover to provide soft feel at impact. This spatial differentiation of material properties resolves the contradiction between resilience and soft feel.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining different rubber compositions with distinct hardness characteristics in a single core structure. The first rubber composition provides resilience and the second rubber composition provides complementary properties, creating a composite core that simultaneously supports both resilience performance and soft feel when paired with the flexible cover.

Inventive Principle:

Principle #40Composite materials

2Productivity

If core structure is improved to enhance flight performance, then flight distance is improved, but controllability and spin performance deteriorate

Engineering Contradiction:

Improveflight distanceVSAvoidcontrollability

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The patent applies local quality by creating different hardness zones within the core structure. The core has a first hardness region and a second hardness region with different Shore-C hardness values, allowing the inner portion to provide resilience while the outer portion works with the flexible cover to provide soft feel at impact. This spatial differentiation of material properties resolves the contradiction between resilience and soft feel.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses parameter changes by systematically varying the Shore-C hardness values of different core regions and adjusting the composition ratios of rubber materials. By optimizing these parameters, the core achieves the right balance between providing flight performance and maintaining controllability and spin characteristics when combined with the flexible cover.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12623120B2Golf ball

Publication Date: 2026.05.12 SUMITOMO RUBBER INDUSTRIES LTD

AI summary

A golf ball can include a core, a mid layer, and a cover. In the golf ball, a hardness Ho at a central point of the core, a core surface hardness Hs, a hardness H1 at a point to which a distance from the central point of the core can be equal to 25% of a radius of the core, a hardness H2 at a point to which a distance from the central point of the core can be equal to 75% of the radius of the core, a hardness Hm of the mid layer, and a hardness Hc of the cover can satisfy all of the following relational expressions:Ho≤H⁢1≤H⁢2≤Hs(1)Ho<Hs(2)(Hm-Hc)≤(Hs-Ho)(3)(Hs-Hc)≤(Hm-Hs).(4)