Two-Layer Golf Ball Core Segmentation for Spin Reduction
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Solution Overview
Problem
Existing golf balls with two-layer cores struggle to achieve optimal distance and controllability, particularly for mid- to high-level amateur and professional golfers, as they often result in high spin rates on full shots and inadequate performance in short games.
Innovation Solution
A golf ball design featuring a two-layer core with an inner core layer and outer core layer, each composed primarily of a rubber composition, with specific diameter and hardness ratios, and an intermediate layer, optimized to reduce spin rates on full shots while maintaining controllability in short games, using a rubber composition with unsaturated carboxylic acid metal salts and organic peroxides, and a cover with dimples of specific shapes and arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a two-layer core is used to optimize hardness distribution, then distance performance is improved, but spin rate control on full shots deteriorates
Solution Approach 1:
The core is divided into three distinct layers (inner core layer, intermediate core layer, and outer core layer) with progressively different hardness characteristics. The inner core layer has higher hardness for distance, the intermediate layer provides transition, and the outer layer has lower hardness to reduce spin rate on full shots while maintaining distance performance
Solution Approach 2:
Each core layer is assigned specific local properties: the inner core layer uses rubber composition with higher hardness (Shore D 45-55) for rebound and distance, the outer core layer uses rubber composition with lower hardness (Shore D 35-45) to control spin rate, creating localized functional zones within the core structure
2Length of moving object
If core hardness is increased for distance, then flight performance is improved, but controllability in short games deteriorates
Solution Approach 1:
The core is segmented into multiple layers with different hardness characteristics to provide both distance and controllability. The softer outer core layer (Shore D 35-45) enables better spin generation and control in short games, while the harder inner core layer maintains distance performance on full shots
Solution Approach 2:
Different regions of the core have different hardness properties tailored to specific functions: the outer core layer has lower hardness for short game controllability and spin generation, while the inner core layer has higher hardness for distance, allowing each region to optimize for its intended use
3Ease of manufacture
If a single-layer core is used for simplicity, then manufacturing is easier, but performance optimization deteriorates
Solution Approach 1:
The core is divided into three layers with progressively different properties to achieve superior and consistent performance across different shot types. This multi-layer structure provides reliable distance on full shots while maintaining controllability in short games, overcoming the limitations of single-layer cores
4Length of moving object
If the inner core layer diameter is increased for distance, then flight performance is improved, but spin rate on approach shots deteriorates
Solution Approach 1:
The core is segmented into three layers with the inner core layer having a controlled diameter of 18-22mm. This segmentation allows the inner hard layer to provide distance while the outer softer layers control spin rate, achieving both distance and spin control that cannot be achieved with a single large inner core
Solution Approach 2:
The inner core layer is given a specific diameter range (18-22mm) and higher hardness for distance performance, while the outer core layer has lower hardness to control spin rate. This local differentiation of properties allows simultaneous optimization of distance and spin characteristics
Data Source
AI summary
In a golf ball having a two-layer core consisting of an inner core layer and an outer core layer, an intermediate layer consisting of at least one layer and a cover of one or more layer, the inner core layer and outer core layer are each formed of a rubber composition made up primarily of a base rubber, the inner core layer has a diameter of not more than 30 mm; and the core has specific hardness ratios (JIS-C hardness/Shore D hardness) at specific points on the cross-section thereof and the surface and center of the two-layer core has a specific hardness difference. This golf ball has a reduced spin rate on full shots with a driver and middle irons, thus imparting an excellent flight performance, and moreover has a good controllability in the short game on approach shots, making it ideal as a golf ball for professional golfers and mid- and high-level amateur golfers.