Golf Club Shaft Flexural Rigidity Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current golf club shafts experience inadequate flexure release during a swing, leading to reduced ball directionality and speed, as the flexural rigidity distribution does not effectively enhance both flexure amount and release.
Innovation Solution
A golf club shaft with a laminate of fiber-reinforced resin layers, featuring a specific distribution of flexural rigidity and surface polishing, where the thinnest part is positioned between 50% and 75% of the shaft's length, with a flexural rigidity ratio of EIc/EIm between 2 and 3, and a polishing amount difference of at least 0.01 mm, to optimize flexure and release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the flexural rigidity distribution is optimized to increase flexure amount, then the shaft can achieve larger flexure, but the release of flexure becomes insufficient leading to poor ball directionality
Solution Approach 1:
The shaft employs different flexural rigidity values at different axial positions. The thinnest part is strategically positioned between 50%-75% of the shaft length from the tip, creating localized flexibility variations. This allows the shaft to have optimal flexure characteristics in the mid-section while maintaining sufficient release capability through the rear portion, resolving the contradiction between maximizing flexure and ensuring proper release for ball directionality.
Solution Approach 2:
The shaft's flexural rigidity distribution is designed to dynamically respond to the swing phases. During the downswing, the thinnest part region provides enhanced flexure accumulation. As the swing progresses to impact, the rigidity distribution facilitates progressive release of stored elastic energy, ensuring the shaft returns to its neutral position at the optimal moment for consistent ball directionality.
2Speed
If the shaft is designed for large flexure, then head speed can be increased, but the flexure release becomes insufficient reducing overall performance
Solution Approach 1:
The invention specifies precise parameters for the shaft design: the thinnest part position (50%-75% from tip) and the flexural rigidity ratio (EIc/EIm between 2-3). These parameter optimizations ensure that the shaft accumulates sufficient flexure during the downswing to maximize head speed, while the rigidity distribution parameters guarantee timely and complete release at impact, preventing any loss of performance.
3Strength
If the thinnest part is positioned to maximize flexure, then flexure amount increases, but the flexural rigidity ratio becomes unbalanced affecting release characteristics
Solution Approach 1:
The shaft design creates a localized thinnest part region positioned between 50%-75% of the shaft length from the tip, rather than uniform thinning. This local quality variation allows maximum flexure in the critical mid-section while the rear portion maintains higher rigidity (EIc/EIm ratio of 2-3) to ensure stable and controlled release characteristics, balancing both objectives.
Solution Approach 2:
The shaft exhibits asymmetric thickness distribution along its length, with the thinnest part strategically positioned in the mid-section (50%-75% from tip) rather than at the center or ends. This asymmetric design, combined with the controlled flexural rigidity ratio, enables the shaft to achieve optimal flexure in the flexing region while maintaining structural stability and proper release characteristics through the asymmetric rigidity distribution.
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
This design enhances the shaft's ability to achieve a large flexure amount and its proper release, resulting in increased head speed and improved ball directionality, thereby increasing flight distance and reducing the likelihood of slice or hook.
Implementation Method 1
A golf club shaft flexes during a swing. In particular, in the early stage of a downswing, the flexure of the shaft is caused by the inertia of a head.
Implementation Method 2
In particular, in the early stage of a downswing, the flexure of the shaft is caused by the inertia of a head.
Implementation Method 3
The angular acceleration of the shaft decreases gradually from the downswing to the impact to release the flexure of the shaft. This release of the flexure accelerates the speed of the head to obtain a large flight distance.
Data Source
AI summary
A shaft 6, which is a tubular body, includes a laminate of fiber reinforced resin layers. This fiber reinforced resin layer includes a matrix resin and a fiber. When a portion with a minimum thickness in the entire shaft is defined as a thinnest part, the entire thinnest part exists in a range of a first position to a second position. The first position is a position where an axial distance from a tip of the shaft is 50% of a full length of the shaft. The second position is a position where the axial distance from the tip of the shaft is 75% of the full length of the shaft. In this shaft 6, a flexural rigidity value EIc (N/m2) of the shaft at a point which is 175 mm away from a rear end of the shaft is two times or greater and three times or less of a flexural rigidity value EIm (N/m2) of the thinnest part.