Golf Club Shaft Hoop Layer Disposition for Flexure Return
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Solution Overview
Problem
Existing golf club shafts fail to achieve optimal head speed and directional stability due to suboptimal disposition and specifications of hoop and bias layers, leading to inadequate flexure return and torsional vibration.
Innovation Solution
A golf club shaft design featuring a full-length hoop layer with a fiber elastic modulus of 30-40 tf/mm2 and a high elasticity bias layer with pitch-based carbon fibers, where the hoop layer is disposed outside the bias layer to enhance crushing rigidity and flexure return, while the bias layer with hybrid prepregs of pitch-based and PAN-based carbon fibers improves torsional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional hoop layer with lower fiber elastic modulus is used, then the shaft weight is reduced, but the crushing rigidity and flexure return are insufficient
Solution Approach 1:
The patent changes the fiber elastic modulus parameter of the hoop layer to a specific range (30-40 tf/mm2) to optimize the balance between crushing rigidity and weight. This parameter optimization allows the shaft to achieve sufficient crushing resistance without excessive weight gain.
Solution Approach 2:
The patent uses composite material structure with multiple layers including hoop layer, bias layers, and straight layers with different fiber orientations and material properties. This composite structure achieves both crushing rigidity and weight reduction by distributing functional requirements across different layers.
2Speed
If the hoop layer is disposed inside the bias layer, then the manufacturing process is simpler, but the flexure return and head speed are reduced
Solution Approach 1:
The patent inverts the conventional layer disposition by placing the hoop layer outside the bias layer instead of inside. This inversion optimizes the flexure return characteristics and head speed by allowing the hoop layer to effectively constrain radial deformation during the swing.
3Reliability
If a bias layer with only PAN-based carbon fiber is used, then the manufacturing cost is lower, but the torsional stability and directional stability are insufficient
Solution Approach 1:
The patent uses composite material structure with multiple layers including hoop layer, bias layers, and straight layers with different fiber orientations and material properties. This composite structure achieves both crushing rigidity and weight reduction by distributing functional requirements across different layers.
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 a high head speed and directional stability by optimizing flexure return and reducing torsional vibration, resulting in improved performance and reduced weight.
Implementation Method 1
a high elasticity containing bias layer constituted with a prepreg containing a high elastic pitch-based carbon fiber having a fiber elastic modulus of equal to or greater than 80 (tf/mm2)
Implementation Method 2
a full length hoop layer constituted with a prepreg having a fiber elastic modulus of equal to or greater than 30 (tf/mm2)
Data Source
AI summary
A shaft 6 includes a plurality of layers formed by fiber reinforced resins. The layers include a hoop layer and bias layers. The hoop layer includes a full length hoop layer s9 constituted with a prepreg having a fiber elastic modulus of equal to or greater than 30 (tf/mm2) and having a fiber weight per unit area of equal to or greater than 50 (g/m2) but equal to or less than 80 (g/m2). The bias layers s2, s3, s4, and s5 include high elasticity containing bias layers s4 and s5 constituted with a prepreg contacting a high elastic pitch-based carbon fiber having a fiber elastic modulus of equal to or greater than 80 (tf/mm2). Preferably, the full length hoop layer s9 is disposed outside the high elasticity containing bias layers s4 and s5.