Multi-piece Golf Ball Hardness Gradient for Spin Control
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Solution Overview
Problem
Multi-piece solid golf balls struggle to achieve both excellent distance performance and spin performance on approach shots, particularly for professional golfers and skilled amateurs, due to inadequate spin rate control and trajectory maintenance during high head-speed shots.
Innovation Solution
A golf ball design with a core, envelope layer, and cover structure featuring specific hardness profiles and layer thicknesses, where the cover is hard on the inside and soft on the outside, and the intermediate layer is harder than the cover, with optimized initial velocities and hardness gradients to reduce spin rates and maintain a straight trajectory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cover is made soft to improve spin performance on approach shots, then spin rate increases, but distance performance on driver shots decreases
Solution Approach 1:
The cover is designed with non-uniform hardness distribution, being harder at the equator region and softer at the polar regions. This local differentiation allows the equatorial hardness to reduce spin on driver shots for distance, while the polar softness maintains spin performance on approach shots
Solution Approach 2:
The cover is divided into functionally distinct regions (equatorial and polar) with different hardness characteristics. This segmentation allows each region to independently optimize for its specific function: distance on driver shots and spin on approach shots
2Speed
If the core hardness is increased to reduce spin rate on driver shots, then distance performance improves, but controllability on approach shots deteriorates
Solution Approach 1:
The core features a non-uniform hardness profile with different hardness values at the center versus the outer regions. This local hardness variation allows the core to provide the spin rate-lowering effect needed for distance on driver shots while maintaining sufficient softness for controllability on approach shots
3Stability of the object's composition
If the intermediate layer is made harder to improve flight stability, then trajectory control improves, but spin performance on approach shots decreases
Solution Approach 1:
The intermediate layer is designed with non-uniform hardness distribution, being harder at the equator and softer at the poles. This local differentiation allows equatorial hardness to stabilize flight trajectory while polar softness preserves spin performance on approach shots
Data Source
AI summary
In a multi-piece solid golf ball having a core, an envelope layer encasing the core, an intermediate layer encasing the envelope layer, and an outermost layer encasing the intermediate layer, the envelope layer-encased sphere, the intermediate layer-encased sphere and the ball have surface hardnesses which satisfy a specific relationship, the intermediate layer and the cover have thicknesses which satisfy a specific relationship, and the core has a hardness profile in which the hardnesses at the core surface, core center, a position 5 mm from the core center, and a position midway between the core surface and center satisfy specific relationships. This golf ball satisfies at a high level the flight and control performances desired for use by professional golfers and skilled amateurs. In particular, it holds down the spin rate on full shots and follows a straight trajectory, thus having a superior flight performance, and moreover is endowed with an excellent scuff resistance.