Golf Ball Core Shallow Hardness Gradient

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Solution Overview

Problem

There is a need for a golf ball with a single-layer core that has a surface hardness differing from its center hardness by up to 10 Shore C, while being inexpensive and efficient to produce, offering unique combinations of compression, feel, spin, and durability.

Innovation Solution

A golf ball with a core formed from a substantially homogenous rubber composition, featuring a carbon-carbon initiator, an intermediate layer, and a cover layer, where the outer surface hardness differs from the geometric center hardness by up to 10 Shore C, achieved through specific curing processes and material compositions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional hard surface to soft center hardness gradient is used in the core, then spin rate and feel are improved, but manufacturing complexity and production time increase due to multiple layers or surface treatments

Engineering Contradiction:

Improvespin rate and feelVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating a hardness gradient within a single-layer core, where the hardness varies from the surface to the center. This is achieved through controlled curing processes that create a softer outer region and a harder inner region, allowing the core to exhibit different mechanical properties at different locations without requiring multiple layers or surface treatments.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent merges the functions of multiple layers into a single-layer core structure. By using a single-layer construction with an integrated hardness gradient, the patent combines what would traditionally require separate core layers or surface treatments into one unified structure, simplifying manufacturing while maintaining the desired spin rate and feel characteristics.

Inventive Principle:

Principle #5Merging (Combining)

2Strength

If multiple layers or surface treatments are applied to create hardness gradient, then compression and durability are improved, but production efficiency decreases and cost increases

Engineering Contradiction:

Improvecompression and durabilityVSAvoidproduction efficiency

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The patent applies parameter changes by controlling the curing conditions (temperature, time, and chemical composition) to create a hardness gradient within a single-layer core. By adjusting these curing parameters, the patent achieves the desired compression and durability characteristics without the need for multiple layers or complex surface treatments, thereby maintaining production efficiency.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent segments the core into regions with different hardness levels (softer outer region and harder inner region) within a single-layer structure. This segmentation is achieved through controlled curing that creates radial variations in crosslinking density, allowing the core to exhibit differentiated mechanical properties while remaining a single integrated layer, thus improving production efficiency.

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If a single-layer core with hardness gradient is used, then production cost and time are reduced, but achieving precise hardness control (up to 10 Shore C difference) becomes more difficult

Engineering Contradiction:

Improveproduction cost and timeVSAvoidhardness control precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies feedback by using a cure-altering agent that responds to conditions during the curing process to automatically adjust and maintain the desired hardness gradient. The agent monitors and regulates the crosslinking reaction, ensuring that the softer outer region and harder inner region achieve the precise hardness difference (up to 10 Shore C) required, while simplifying the manufacturing process.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent uses a cure-altering agent as an intermediary to facilitate the creation of the hardness gradient. This agent mediates the curing process by controlling the rate and extent of crosslinking at different radial positions within the core, enabling precise hardness control while maintaining a simple single-layer construction and efficient production process.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution provides a golf ball with a tailored hardness gradient that enhances compression, feel, and spin, while being cost-effective and efficient in production, offering improved performance characteristics.

Implementation Method 1

a core having an outer surface and a geometric center and being formed from a substantially homogenous rubber composition comprising a carbon-carbon initiator

Methodology Applied

Scientific EffectFree radical crosslinking: Photopolymerisation

Data Source

PatentUS9056227B2Golf ball comprising a core having a shallow hardness gradient

Publication Date: 2015.06.16 ACUSHNET CO

AI summary

A golf ball comprising: a core having an outer surface and a geometric center and being formed from a substantially homogenous rubber composition comprising a carbon-carbon initiator, wherein the outer surface has a hardness that differs from a hardness at the geometric center by up to about 10 Shore C; optionally an intermediate layer disposed about the core; and a cover layer disposed about the core (or intermediate layer where present).