Fork Crown Arm Structure for Bicycle Frame Weight Reduction
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Solution Overview
Problem
Existing vehicle frame components, such as bicycle forks, face challenges in balancing strength and weight, requiring reinforcement to resist twisting and bending forces while maintaining structural integrity, especially as riders advance in skill and terrain demands change.
Innovation Solution
The implementation of topologically optimized designs for components like fork arches and crowns using additive and subtractive manufacturing processes, which redistribute material to achieve minimum weight while meeting stiffness and stress thresholds, incorporating materials like carbon fiber, titanium, and aluminum, and incorporating features like lightening bores and captured voids for enhanced strength and aerodynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional reinforcement methods are used to resist twisting and bending forces, then structural strength is improved, but component weight increases
Solution Approach 1:
The crown arm is divided into multiple regions with different thicknesses and material densities. The topology optimization creates a segmented structure where material is concentrated in high-stress areas and removed from low-stress areas, achieving both strength and weight reduction simultaneously.
Solution Approach 2:
Different regions of the crown arm are given different local properties through variable thickness and material composition. The optimized design creates local reinforcements exactly where needed to resist specific twisting and bending forces, rather than uniformly reinforcing the entire component.
2Strength
If material is added to increase stiffness and strength, then structural integrity is improved, but manufacturing complexity increases
Solution Approach 1:
The invention changes the material distribution parameters through topology optimization, creating a design that is manufactured via additive processes. This allows complex optimized geometries to be produced directly from digital models, reducing manufacturing complexity compared to traditional methods that would require multiple assembly steps.
Solution Approach 2:
The crown arm incorporates composite material structures, particularly carbon fiber reinforced polymers, which provide high strength-to-weight ratio and stiffness. The composite construction allows for complex optimized geometries that would be difficult or impossible to achieve with monolithic materials.
Data Source
AI summary
Disclosed herein is a crown comprising a steerer tube boss, a first upper tube boss, and a second upper tube boss. The first upper tube boss and the second upper tube boss reside on a plane on opposing sides of the upper tube boss, wherein the plane comprises the central axis of the first upper tube boss and the central axis of the second upper tube boss. There is a first arm to connect the first upper tube boss to the steerer tube boss, as well as a second arm to connect the second upper tube boss to the steerer tube boss. At least one of the first arm or the second arm comprises at least one bore that extends in a direction that is substantially normal to the plane.