Golf Ball Core Hardness Gradient for Flight Distance
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Solution Overview
Problem
Golf balls fail to achieve optimal flight distance performance, particularly when hit with a driver, due to inadequate resilience and spin control, despite advancements in core and cover designs.
Innovation Solution
A golf ball design featuring a core with a center and envelope layer, both formed from crosslinked rubber compositions including a base rubber, co-crosslinking agent, crosslinking initiator, and acid or salt, with specific hardness distributions and organic sulfur compounds, to enhance resilience and control spin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a golf ball uses a high spin rate to achieve high trajectory, then trajectory height is improved, but flight distance becomes insufficient
Solution Approach 1:
The patent changes the physical parameters of the core by controlling the crosslinking degree through specific additives (carboxylic acid or salt, co-crosslinking agent) to achieve an optimal hardness distribution. The core hardness is controlled within 50-80 degrees Shore A, with a specific gradient from center to surface, which optimizes the balance between spin rate and launch angle for maximum flight distance
Solution Approach 2:
The patent applies local quality by creating a non-uniform hardness distribution within the core. The core has a softer center region that deforms more easily to generate backspin, while the outer region has higher hardness to maintain structural integrity. This radial gradient in hardness (achieved through controlled crosslinking) allows different regions to perform different functions during impact
2Productivity
If a golf ball uses an outer-hard/inner-soft structure to achieve low spin rate and high launch angle, then flight distance is improved, but manufacturing precision becomes more difficult
Solution Approach 1:
The patent uses carboxylic acid or salt and co-crosslinking agents as intermediary substances that facilitate controlled crosslinking during the core formation process. These additives act as mediators between the rubber composition and the desired hardness profile, enabling the outer-hard/inner-soft structure to be achieved through a single-molding process rather than requiring multiple layers or post-processing
Solution Approach 2:
The patent controls the crosslinking reaction parameters by specifying the types and amounts of carboxylic acid/salt and co-crosslinking agent. By adjusting these chemical parameters during manufacturing, the desired hardness gradient (50-80 Shore A overall, with specific center-to-surface variation) is achieved consistently, making the manufacturing process precise and repeatable
3Speed
If a golf ball core uses high resilience performance materials, then flight speed is improved, but spin control becomes inadequate
Solution Approach 1:
The patent applies local quality by creating distinct regions within the core with different hardness characteristics. The softer central region (lower crosslinking degree) provides high resilience and elastic recovery for maximum flight speed, while the harder outer region (higher crosslinking degree) provides friction and deformation control for optimal spin generation. This spatial differentiation of material properties resolves the contradiction between speed and spin control
Solution Approach 2:
The patent uses a composite rubber composition in the core that combines base rubber with controlled amounts of carboxylic acid/salt and co-crosslinking agents. This creates a composite material system where the crosslinked and non-crosslinked regions coexist, providing both the resilience needed for high flight speed and the surface characteristics needed for spin control during driver impact
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves low energy loss and appropriate hardness distribution, resulting in improved flight distance and resilience performance when hit with a driver, while suppressing spin and maintaining durability.
Implementation Method 1
The center is formed by a rubber composition being crosslinked. The envelope layer is formed by a rubber composition being crosslinked.
Data Source
Figure 1
Figure 2
AI summary
A golf ball 2 includes a core 4 and a cover 6. The core 4 includes a center 8 and an envelope layer 10 each of which is formed by a rubber composition being crosslinked. At least one of the rubber compositions of the center 8 and the envelope layer 10 includes a base rubber (a), a co-crosslinking agent (b), a crosslinking initiator (c), and an acid and/or a salt (d). The co-crosslinking agent (b) is: (b1) an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms; or (b2) a metal salt of an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms. A hardness H (Ie) at an innermost portion of the envelope layer 10 is greater than a hardness H(Sc) at an outermost portion of the center 8. A hardness Ho of the cover 6 is greater than a hardness Hs at a surface of the core 4.