Golf Ball Coating Roughness for Drag Reduction

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Solution Overview

Problem

Golf balls tend to pop up when hit with a middle iron, resulting in reduced flight-distance, and existing dimple designs have not adequately addressed this aerodynamic performance issue.

Innovation Solution

A golf ball with a spherical core, cover member, and a coating layer featuring dimples and surface roughness, where the arithmetic average roughness is 0.5 µm or more and maximum height is 4.0 µm or more, optimized to achieve a specific relationship between drag and lift coefficients at various spin rates, enhancing aerodynamic performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If conventional dimple designs are used, then the golf ball achieves basic aerodynamic performance, but the ball pops up when hit with middle iron resulting in reduced flight-distance

Engineering Contradiction:
Improveflight-distanceVSAvoidflight stability
Core Design Contradiction:
Duration of action of moving objectVSEase of operation

Solution Approach 1:

The patent applies parameter changes by introducing surface roughness with specific quantitative parameters (arithmetic average roughness Ra of 0.5 µm or more and maximum height Rz of 4.0 µm or more) on the coating layer. This modifies the aerodynamic parameters (drag coefficient CD and lift coefficient CL) to achieve optimal flight performance that prevents pop-up while extending flight-distance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by creating localized surface roughness on specific regions of the coating layer rather than uniformly modifying the entire ball surface. The roughness is formed through selective particle spraying or surface treatment methods, creating localized aerodynamic modifications that stabilize flight without affecting overall ball performance.

Inventive Principle:
Principle #3Local quality

2Duration of action of moving object

If surface roughness is added to the coating layer, then aerodynamic performance is enhanced and flight-distance is extended, but manufacturing complexity increases

Engineering Contradiction:
Improveflight-distanceVSAvoidmanufacturing process
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by forming the roughness on the coating layer during the manufacturing process itself, rather than as a separate post-processing step. The coating layer is applied with embedded particles or surface treatment is performed while the coating is still in a manageable state, integrating the roughness formation into the existing manufacturing workflow.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies porous materials by incorporating minute particles into the coating layer to create a controlled porous or rough surface structure. This roughness is formed by embedding particles with specific size distributions during coating application, creating a surface topology that enhances aerodynamic performance while using readily available particulate materials.

Inventive Principle:
Principle #31Porous materials

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 golf ball design significantly extends flight-distance by optimizing the relationship between drag and lift coefficients, reducing the likelihood of the ball popping up and improving overall flight performance across different spin conditions.

Implementation Method 1

The dimples disturb airflow around the golf ball during flight and cause turbulent separation. This phenomenon is referred to as 'turbulence'. Turbulence causes a separation point of air from the golf ball to shift rearward, and thus drag is reduced.

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 2

turbulence promotes the displacement between an upper separation point and a lower separation point due to backspin, and thus lift acting on the golf ball is enhanced

Methodology Applied
Scientific EffectMagnus effect: Magnus Effect

Data Source

PatentEP2889059B1Golf ball and method for producing the same
Publication Date: 2017.08.23 DUNLOP SPORTS CO LTD
  • EP2889059B1 patent drawingFigure 1~2
  • EP2889059B1 patent drawingFigure 3
  • EP2889059B1 patent drawing

AI summary

A golf ball that enhances flight performance is provided. A golf ball according to the present invention includes a spherical core, at least one cover member that covers the core, and a coating layer that covers the cover member configuring the outermost layer. A plurality of dimples are formed in the cover member configuring the outermost layer. Roughness is formed on a surface of the coating layer such that a relationship between a drag coefficient CD1 and a lift coefficient CL1 when a golf ball is hit with a Reynolds number of 1.77×105 and a spin amount of 2280 rpm satisfies CD1×CL1<0.0370.