Golf Ball Core Hardness Gradient for Distance and Spin Control

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Solution Overview

Problem

Current golf ball designs fail to optimize flight distance on driver shots, particularly for average golfers, due to excessive spin rates caused by soft intermediate layer hardness.

Innovation Solution

The golf ball features a spherical core with a two-layered construction, an intermediate layer, and a cover, where the hardness gradients of the core layers and the intermediate layer are optimized to increase initial velocity and suppress excessive spin rates, resulting in a greater flight distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the intermediate layer hardness is soft, then the shot feeling is improved, but the spin rate increases excessively reducing flight distance

Engineering Contradiction:
Improveshot feelingVSAvoidexcessive spin rate
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating distinct hardness zones within the core structure. The inner layer core is made softer (50-85 Shore C) to provide cushioning and good shot feeling, while the outer layer core is made harder (70-90 Shore C) to reduce spin rate and increase flight distance. This spatial variation in hardness allows simultaneous optimization of shot feeling and distance performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining different rubber compositions with varying hardness characteristics in a single core structure. The inner layer uses a softer rubber composition while the outer layer uses a harder rubber composition, creating a composite core that delivers both good shot feeling and reduced spin rate, thereby increasing flight distance.

Inventive Principle:
Principle #40Composite materials

2Length of moving object

If the core hardness is increased, then the flight distance is improved, but the spin rate increases reducing trajectory control

Engineering Contradiction:
Improveflight distanceVSAvoidspin rate
Core Design Contradiction:
Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating distinct hardness zones within the core structure. The inner layer core is made softer (50-85 Shore C) to provide cushioning and good shot feeling, while the outer layer core is made harder (70-90 Shore C) to reduce spin rate and increase flight distance. This spatial variation in hardness allows simultaneous optimization of shot feeling and distance performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining different rubber compositions with varying hardness characteristics in a single core structure. The inner layer uses a softer rubber composition while the outer layer uses a harder rubber composition, creating a composite core that delivers both good shot feeling and reduced spin rate, thereby increasing flight distance.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If the core structure is simplified, then the manufacturing is easier, but the resilience performance is insufficient

Engineering Contradiction:
Improvecore construction complexityVSAvoidresilience performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies segmentation by dividing the core into two distinct layers with different hardness characteristics. The inner layer core and outer layer core are manufactured as separate components that are then assembled together, allowing each layer to be optimized independently for its specific function while maintaining overall manufacturing feasibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by creating distinct hardness zones within the core structure. The inner layer core is made softer (50-85 Shore C) to provide cushioning and good shot feeling, while the outer layer core is made harder (70-90 Shore C) to reduce spin rate and increase flight distance. This spatial variation in hardness allows simultaneous optimization of shot feeling and distance performance.

Inventive Principle:
Principle #3Local quality

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 optimized hardness distribution and layer configuration enhance resilience and reduce spin rates, leading to improved flight distance and shot feeling on driver shots.

Implementation Method 1

a spherical core, an intermediate layer positioned outside the spherical core, and a cover positioned outside the intermediate layer

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the hardness gradients of the core layers and the intermediate layer are optimized to increase initial velocity and suppress excessive spin rates

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3088060B1Golf ball
Publication Date: 2019.04.10 SUMITOMO RUBBER INDUSTRIES LTD
  • EP3088060B1 patent drawingFigure 1~2
  • EP3088060B1 patent drawingFigure 3~4
  • EP3088060B1 patent drawingFigure 5~6

AI summary

An object of the present invention is to provide a golf ball traveling a great distance on driver shots. The present invention provides a golf ball comprising a spherical core including an inner layer and an outer layer, an intermediate layer and and a cover, wherein a difference (HX+1-HX-1) between a hardness (HX+1) at a point outwardly away in a radial direction from a boundary between the inner layer and the outer layer of the spherical core by 1 mm and a hardness (HX-1) at a point inwardly away in the radial direction from the boundary between the inner layer and the outer layer of the spherical core by 1 mm is 0 or more in Shore C hardness, a surface hardness (HX+Y) of the spherical core is more than 70 in Shore C hardness, an angle α of a hardness gradient of the inner layer is 0º or more, a difference (α-β) between the angle α and an angle β of a hardness gradient of the outer layer is 0º or more, the intermediate layer has a material hardness (Hm) ranging from 65 to 80 in Shore D hardness, and the intermediate layer has a highest hardness among the constituent members of the golf ball.