Multi-layer Golf Ball Core Hardness Gradient

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Solution Overview

Problem

Existing golf ball designs with multi-layer cores lack optimal combinations of thermoset rubber and thermoplastic materials for achieving desired hardness gradients and compression levels, affecting performance characteristics such as spin rate and initial velocity.

Innovation Solution

A golf ball construction featuring a multi-layer core comprising a thermoset rubber inner core, a thermoset rubber first intermediate core layer, a thermoplastic second intermediate core layer, and a thermoset rubber outer core layer, with specific hardness and thickness specifications for each layer to enhance performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a multi-layer core structure is used with thermoset rubber and thermoplastic materials, then the hardness gradient and compression levels are improved, but the device complexity increases

Engineering Contradiction:

Improvehardness gradientVSAvoidcore structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The core is divided into multiple layers (inner core layer, first intermediate core layer, second intermediate core layer, outer core layer) with different material compositions and hardness levels. This segmentation allows each layer to contribute differently to the overall performance, creating an optimized hardness gradient from center to surface while managing the complexity through systematic layering.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the core are assigned different material properties: the inner core layer uses soft thermoset rubber for compression, the intermediate layers use thermoplastic materials for structural support, and the outer core layer uses harder thermoset rubber for surface durability. This local differentiation of material qualities achieves the desired hardness gradient while addressing specific performance requirements in different zones.

Inventive Principle:

Principle #3Local quality

2Speed

If multiple thermoset rubber and thermoplastic layers are combined, then the spin rate and initial velocity are enhanced, but the manufacturing precision requirements increase

Engineering Contradiction:

Improveinitial velocityVSAvoidlayer thickness control

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The patent specifies precise parameter ranges for each layer including thickness (e.g., inner core layer diameter of 0.500-1.580 inches, outer core layer thickness of 0.010-0.100 inches) and hardness (Shore C and Shore D values). By establishing these parameter specifications, the design balances the need for enhanced performance with manufacturable precision requirements, allowing manufacturers to target specific ranges rather than exact values.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The core combines thermoset rubber materials (providing elasticity and compression characteristics) with thermoplastic materials (providing structural integrity and layer adhesion). This composite approach enables the different layers to work together synergistically, where the thermoplastic intermediate layers bond the thermoset layers while each material type contributes its advantageous properties to the overall performance.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS8137215B2Multi-layer core golf ball

Publication Date: 2012.03.20 ACUSHNET CO

AI summary

Golf balls comprising a multi-layer core and a cover are disclosed. The multi-layer core comprises a thermoset rubber inner core, a thermoset rubber first intermediate core layer, a thermoplastic second intermediate core layer, and a thermoset rubber outer core layer. The inner core is preferably formed from a softer rubber than the first intermediate core layer.