Multi-layer Core Golf Ball Hardness Gradient

Solution Overview

Problem

Current golf balls do not effectively achieve a very high positive gradient core with a very soft, low compression inner core layer formed from an unfoamed composition, which is necessary for durability and spin reduction.

Innovation Solution

A golf ball design featuring a core with an inner core layer made from an unfoamed first thermoplastic composition and an outer core layer formed from a second thermoplastic composition, where the outer core layer has a thickness of 0.200 inches or greater and an outer surface Shore C hardness at least 40 points greater than the inner core layer's center Shore C hardness, creating a steep positive hardness gradient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If a soft inner core layer is used to reduce spin off the driver, then spin reduction is improved, but durability deteriorates

Engineering Contradiction:

Improvespin off driverVSAvoiddurability

Core Design Contradiction:

Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent applies local quality by creating distinct hardness zones within the core structure. The inner core layer has a first hardness (softer) while the outer core layer has a second hardness (harder), with the hardness gradient localized to specific regions. This allows the soft inner core to reduce driver spin while the hard outer core maintains durability, resolving the contradiction between spin reduction and durability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining different thermoplastic compositions in the inner and outer core layers. The inner core layer uses a first thermoplastic composition with specific properties for spin control, while the outer core layer uses a second thermoplastic composition with different properties for durability. This composite approach allows simultaneous optimization of both spin reduction and durability.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a hard outer core layer is used to improve durability, then durability is improved, but spin reduction deteriorates

Engineering Contradiction:

ImprovedurabilityVSAvoidspin off driver

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating distinct hardness zones within the core structure. The inner core layer has a first hardness (softer) while the outer core layer has a second hardness (harder), with the hardness gradient localized to specific regions. This allows the soft inner core to reduce driver spin while the hard outer core maintains durability, resolving the contradiction between spin reduction and durability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining different thermoplastic compositions in the inner and outer core layers. The inner core layer uses a first thermoplastic composition with specific properties for spin control, while the outer core layer uses a second thermoplastic composition with different properties for durability. This composite approach allows simultaneous optimization of both spin reduction and durability.

Inventive Principle:

Principle #40Composite materials

3Object-generated harmful factors

If a high positive gradient core is used to reduce spin, then spin reduction is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvespin off driverVSAvoidcore structure complexity

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the core into distinct inner and outer layers, each with specific hardness ranges and functional properties. The inner core layer (softer) and outer core layer (harder) are manufactured separately and then assembled, simplifying the production of the high positive gradient structure compared to creating a continuous gradient in a single piece.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses an intermediate layer between the inner and outer core layers to facilitate the transition between different hardness zones. This intermediary layer simplifies manufacturing by providing a buffer zone that eases the transition from the soft inner core to the hard outer core, reducing the complexity of achieving a high positive gradient.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9649538B2Multi-layer core golf ball

Publication Date: 2017.05.16 ACUSHNET CO

AI summary

A golf ball comprising a core and a cover, the core consisting of: a solid inner core layer formed from a first unfoamed thermoplastic composition TP1 and having a diameter of 1.10 inch or less and a center Shore C hardness (Hcenter) of 50 or less, one or more optional intermediate core layers, and an outer core layer formed from a second thermoplastic composition TP2 and having a thickness of 0.200 inches or greater and an outer surface Shore C hardness (Houter surface) of 70 or greater, wherein Houter surface>Hcenter, and Houter surface−Hcenter≧40.