Golf Ball Core Hardness Gradients for Spin and Feel Tuning
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Solution Overview
Problem
Existing golf balls do not adequately tailor core hardness gradients to meet the diverse performance needs of golfers with varying skill levels, leading to inconsistent spin rates and feel, which affects shot control and comfort.
Innovation Solution
Golf balls with core layers featuring tailored hardness gradients, achieved through specific rubber compositions and curing processes, including water-releasing agents and cross-linking co-agents, to create positive and zero hardness gradients, allowing for customizable spin rates and feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the core hardness gradient is increased to reduce spin rate for recreational players, then shot dispersion is reduced, but professionals and skilled amateurs lose control capability and ability to draw/fade on approach shots
Solution Approach 1:
The patent applies local quality by creating different hardness gradients in different core layers. The inner core layer has a first hardness gradient while the outer core layer has a second hardness gradient, allowing different regions of the core to provide different functional characteristics. This enables the ball to provide both low spin for recreational players and high spin control for professionals through selective layer design.
Solution Approach 2:
The core is segmented into multiple layers with distinct hardness gradient characteristics. By dividing the core into an inner core layer and an outer core layer, each with tailored hardness gradients, the patent enables independent optimization of spin characteristics for different player skill levels without compromising overall ball performance.
2Strength
If the core hardness is increased to improve resiliency and rebounding performance, then Coefficient of Restitution is improved, but the feel of the ball becomes harder and less comfortable for players
Solution Approach 1:
The patent creates local quality differences within the core by implementing varying hardness gradients across different core layers. The inner core layer can be designed with properties that maximize resiliency and rebounding, while the outer core layer is designed to provide a softer feel at the surface, thus simultaneously achieving both high CoR and comfortable feel.
Solution Approach 2:
The core uses a composite structure with multiple layers having different rubber compositions and hardness gradient profiles. This composite approach allows the ball to exhibit both high resiliency from the inner layers and soft feel from the outer layers, resolving the contradiction between strength and ease of operation.
3Ease of manufacture
If a single core design is used for all golfers, then manufacturing is simplified, but it cannot meet the diverse performance needs of golfers with varying skill levels
Solution Approach 1:
The core is segmented into multiple manufacturable layers with standardized materials and processes. Each layer can be produced using conventional rubber composition and curing techniques, maintaining ease of manufacture while enabling performance tailoring through controlled hardness gradients in each layer.
Solution Approach 2:
The multi-layer core structure with controllable hardness gradients provides universal applicability across different player skill levels. By adjusting the hardness gradient parameters of the inner and outer core layers, the same basic construction can serve both recreational players needing low spin and professionals needing high spin control.
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 tailored hardness gradients enhance golf ball performance by providing desired spin rates and feel for both professionals and recreational players, improving shot control and comfort.
Implementation Method 1
the core is formed from a rubber composition cured under heat, the rubber composition including a base rubber, an organic peroxide, a cross-linking co-agent
Implementation Method 2
the core is formed from a rubber composition cured under heat
Implementation Method 3
the water releasing agents are calcium sulfate dihydrate, zinc sulfate heptahydrate, and aluminum sulfate hydrate
Data Source
AI summary
Golf balls having core layers with individual hardness gradients are provided. The cores have at least one layer with an increased “positive” hardness gradient (or a “hard-to-soft” hardness) where the outer surface of the core is harder than the center. The increased positive hardness gradient can be achieved by introducing a water-releasing agent into the core rubber formulation during the curing process. The cores may also have a “zero” hardness gradient in another layer. By utilizing different hardness gradients in the core layers, the present disclosure allows for the properties of the final golf ball to be manipulated to produce desired performance characteristics.