Golf Ball Layer Hardness and Dimple Volume for High Spin, Low Lift

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Solution Overview

Problem

Existing golf balls face issues with high lift and excessive flying height, leading to an increased number of shots into the out-of-bounds (OB) area, particularly due to unstable swings and golf course features like slopes and obstacles.

Innovation Solution

A golf ball design comprising a spherical core, an intermediate layer, and an outermost cover with specific material hardness, thickness, and dimple configurations that balance spin rate and lift, ensuring a high spin rate without excessive lift, thereby reducing the number of OB shots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the spin rate of the golf ball is increased, then the rolling distance on slopes is reduced, but the lift force increases excessively causing higher flying height

Engineering Contradiction:
Improvespin rateVSAvoidlift force
Core Design Contradiction:
SpeedVSForce

Solution Approach 1:

The patent applies parameter changes by precisely controlling the material hardness values (Shore D hardness) of both the intermediate layer and outermost cover, as well as their thickness ratio. This specific parameter combination allows the golf ball to generate high spin rate while suppressing excessive lift force, resolving the contradiction between rolling control and flight height.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining an intermediate layer and an outermost cover with different material properties. The intermediate layer has a specific Shore D hardness range, and the outermost cover has a different Shore D hardness range, creating a composite structure that balances spin generation and lift control.

Inventive Principle:
Principle #40Composite materials

2Speed

If the material hardness of the intermediate layer and outermost cover are optimized, then the spin rate is increased, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvespin rateVSAvoidhardness control precision
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent defines specific parameter ranges for material hardness (Shore D hardness) of the intermediate layer and outermost cover, along with their thickness ratio. These parameter specifications provide clear manufacturing targets that balance performance optimization with manufacturability, reducing the precision burden while achieving the desired spin rate.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design enhances spin rate while minimizing lift, resulting in a shorter rolling distance on slopes and reduced OB shots, maintaining a controlled flight height and improved flight distance performance.

Implementation Method 1

L1 represents a ratio of a lift force coefficient CL1 which is measured under conditions of a Reynolds number of 1.290×10^5

Methodology Applied
Scientific EffectLift force: Aerofoil

Implementation Method 2

a material hardness Hm (Shore D hardness) of the intermediate layer, a material hardness Hc (Shore D hardness) of the outermost cover, a thickness Tc (mm) of the outermost cover, and a total lower volume Vi (mm^3) of the plurality of dimples satisfy: (Hc/Tc)×(Hm/Vi)≤7.5

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4470635B1Golf ball
Publication Date: 2025.10.15 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4470635B1 patent drawingFigure 1
  • EP4470635B1 patent drawingFigure 2
  • EP4470635B1 patent drawingFigure 3

AI summary

An object of the present disclosure is to provide a golf ball that has a high spin rate but does not fly up in a high maximum flying height, thereby having a reduced number of shots into the OB area on a driver shot. The present disclosure provides a golf ball comprising a spherical core, an intermediate layer and an outermost cover, wherein a material hardness Hm (Shore D hardness) of the intermediate layer, a material hardness He (Shore D hardness) of the outermost cover, a thickness Tc (mm) of the outermost cover, and a total lower volume Vi (mm3) of a plurality of dimples satisfy Vi>365 and (Hc/Tc)×(Hm/Vi)≤7.5.