Golf Ball Core Hardness Gradient for Iron Shot Control
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Solution Overview
Problem
Existing golf balls struggle to maintain controllability on iron shots due to increased backspin rates, which lead to higher flying heights and susceptibility to wind, making it difficult for average golfers to control the flight distance.
Innovation Solution
A golf ball design featuring a spherical core made from a rubber composition containing polybutadiene rubber and butyl rubber, with specific hardness distributions and a predetermined amount of butyl rubber, combined with an intermediate layer and outermost cover with controlled hardness differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the backspin rate is increased to improve spin performance and controllability, then the golf ball achieves better stopping ability at target points, but the maximum flying height increases making the golf ball more susceptible to wind
Solution Approach 1:
The patent applies parameter changes by precisely controlling the butyl rubber content (10-60 mass%) in the base rubber and specifying the hardness distribution parameters (H0, H2.5, H5.0, H7.5, H10, H12.5, H15) to achieve optimal spin performance while managing flight characteristics. This resolves the contradiction by finding the right parameter range that balances backspin rate and flying height
Solution Approach 2:
The patent uses composite materials by combining polybutadiene rubber and butyl rubber in specific proportions to create a base rubber composition. This composite approach allows the core to achieve both the spin performance improvement and the flight stability needed to reduce wind susceptibility
2Reliability
If the butyl rubber amount is increased to control hardness distribution and improve spin performance, then the golf ball achieves better controllability, but the core composition complexity increases
Solution Approach 1:
The patent simplifies the composition complexity by establishing clear parameter ranges: butyl rubber at 10-60 mass% of base rubber and specific hardness differences (H10-H0 ≥ 10 Shore C). These defined parameters provide a straightforward formulation guide that achieves controllability without excessive complexity
Solution Approach 2:
The patent applies local quality by creating a specific hardness distribution pattern within the core through controlled butyl rubber placement. The hardness varies at different radial distances (H0, H2.5, H5.0, H7.5, H10, H12.5, H15) to optimize spin performance while maintaining manageable composition complexity
3Object-affected harmful factors
If the hardness difference between intermediate layer and cover is controlled to reduce flying height, then wind susceptibility decreases, but the manufacturing precision requirements increase
Solution Approach 1:
The patent manages manufacturing precision by specifying the hardness relationship as slab hardness of intermediate layer composition > slab hardness of cover composition, along with core hardness parameters. These clear parameter specifications provide actionable manufacturing guidelines that balance precision requirements with achievable production standards
Data Source
AI summary
An object of the present disclosure is to provide a golf ball having improved controllability on iron shots. The present disclosure provides a golf ball 2 comprising a spherical core 4, an intermediate layer 6 and an outermost cover 8, wherein the spherical core 4 is formed from a rubber composition containing a polybutadiene rubber and a butyl rubber in a predetermined amount, a center hardness (H0) of the spherical core 4 and hardnesses (H2.5, H5.0, H7.5, H10, H12.5, H15) at points having a radial distance of 2.5 mm, 5.0 mm, 7.5 mm, 10 mm, 12.5 mm, 15 mm from a center of the spherical core satisfy a relationship of H0<H2.5<H5.0<H7.5<H10<H12.5<H15, a hardness difference (H10−H0) is 10 or more in Shore C hardness, and a slab hardness of an intermediate layer composition forming the intermediate layer 6 is greater than a slab hardness of a cover composition forming the outermost cover 8.