Golf Ball Core Hardness Gradient for Distance and Durability
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Solution Overview
Problem
Existing golf balls, particularly for amateur golfers, often fail to achieve optimal distance and durability on full shots with both drivers and irons due to inadequate core and intermediate layer hardness profiles, leading to inconsistent performance.
Innovation Solution
A multi-piece solid golf ball design featuring a core with a specific Shore C hardness gradient, an intermediate layer, and a cover, where the core is formed primarily of base rubber with a diameter of at least 32 mm, and the hardness differences between core center and surface are carefully controlled to achieve a lower spin rate and enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the core hardness is increased to improve distance on driver shots, then the spin rate decreases and distance increases, but the durability to repeated impact deteriorates
Solution Approach 1:
The patent applies local quality by creating a non-uniform hardness distribution within the core, where the surface hardness is specifically higher than the core center hardness. This gradient structure allows the surface to provide durability and control while the softer interior maintains rebound characteristics, resolving the contradiction between distance and durability.
Solution Approach 2:
The patent uses composite materials by combining different rubber compositions with varying hardness characteristics in a single core structure. The core is formed from a composite rubber composition that creates a hardness gradient from surface to center, enabling simultaneous optimization of distance and durability properties.
2Length of moving object
If the core hardness gradient is made more pronounced to reduce spin rate, then distance on driver improves, but the hardness difference between center and surface becomes too large, affecting feel and durability
Solution Approach 1:
The patent applies parameter changes by precisely controlling the hardness values at different positions within the core. The surface hardness is set to 70-90 Shore C while the core center hardness is set to 40-60 Shore C, creating a specific hardness gradient range that optimizes both distance and manufacturability.
Solution Approach 2:
The patent implements local quality by creating a non-uniform hardness distribution where the surface hardness is specifically higher than the core center hardness. This gradient structure allows the surface to provide durability and control while the softer interior maintains rebound characteristics.
3Length of moving object
If the core diameter is increased to improve distance, then the ball travels farther, but the manufacturing precision and hardness gradient control become more difficult
Solution Approach 1:
The patent specifies a core diameter range of 32-38 mm as an optimal parameter that balances distance performance with manufacturability. This parameter setting allows for effective hardness gradient control while achieving satisfactory distance on full shots with both driver and iron clubs.
4Reliability
If the ball surface hardness is increased to improve durability, then the durability to repeated impact improves, but the spin rate increases and distance decreases
Solution Approach 1:
The patent resolves this contradiction by creating a hardness gradient where the surface hardness (70-90 Shore C) is higher than the core center hardness (40-60 Shore C). The higher surface hardness provides durability and control, while the softer interior maintains rebound characteristics and prevents excessive spin rate.
Data Source
AI summary
In a golf ball having a core, an intermediate layer and a cover, the core is formed primarily of a base rubber and has a diameter set in a specific range, and the intermediate layer and cover are each formed of resin materials. The core has an internal hardness such that, regarding the hardness at the core center, the hardnesses at positions located at 2 mm intervals from the core center outward up to 16 mm and the core surface hardness, the hardness differences therebetween are set within a specific range. The ball surface hardness is set so as to be higher than the surface hardness of the intermediate layer-encased sphere. This ball achieves a satisfactory distance on full shots not only with a driver, but also with a long iron or a middle iron, in addition to which it has an excellent durability to repeated impact.