Bicycle Frameset Assembly Using Friction Stir Welded Tube Joints
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Solution Overview
Problem
The adoption of friction stir welding (FSW) in consumer products is limited due to the need for significant redesign to accommodate the external, non-consumable tool, which is costly and impractical for many existing products, including bicycle frames and forks, where conventional fusion welding methods dominate.
Innovation Solution
Implementing a novel method and design for assembling bicycle frames and forks using friction stir welding, where tubular components are joined with partial tubular components and structural connector components using a friction stir welding tool, allowing for the construction of high-quality, high-mechanical-property joints without the need for consumables or extensive redesign.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If friction stir welding is adopted for bicycle frames and forks, then manufacturing quality and mechanical properties are improved, but device complexity and redesign costs increase due to the external non-consumable tool requirement
Solution Approach 1:
The patent integrates the FSW tool directly into the bicycle frame structure by nesting the tool housing within the frame tubes. The frame tubes serve dual purposes as both structural components and as the housing for the FSW tool, eliminating the need for external tooling and reducing overall device complexity while maintaining manufacturing precision
Solution Approach 2:
The bicycle frame tubes are designed to perform multiple functions: they serve as structural load-bearing elements and simultaneously house the FSW tool components. This multi-functionality reduces the need for separate external tooling systems, thereby reducing device complexity while enabling high-quality FSW joints
2Stability of the object's composition
If friction stir welding is implemented, then residual stresses and distortion are reduced, but the manufacturing process complexity increases due to tool integration requirements
Solution Approach 1:
The patent merges the FSW tool housing with the bicycle frame tubes, combining two separate systems (welding tool and frame structure) into a single integrated component. This reduces overall process complexity while maintaining the benefits of reduced residual stress and distortion through solid-state welding
3Ease of manufacture
If conventional fusion welding is used, then ease of manufacture is maintained, but harmful factors such as porosity, splatter, and residual stresses increase
Solution Approach 1:
The patent replaces the thermal-melting mechanism of fusion welding with the mechanical-solid state mechanism of friction stir welding. This substitution eliminates harmful factors such as porosity, splatter, and gas fumes associated with molten metal, while the integrated tool design maintains manufacturing ease through direct incorporation into the frame structure
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 approach enables the use of solid-state welding processes for bicycle frames and forks, resulting in reduced residual stresses, distortion, porosity, and splatter, while providing superior mechanical properties and cost benefits, making high-quality bicycle frames and forks feasible with minimal redesign efforts.
Implementation Method 1
one component is rotated in relative motion with respect to the other component and comes into contact with the other component to generate sufficient frictional heating to cause plasticization
Implementation Method 2
Once plasticization occurs, portions of the material are upset from the applied force and a resulting metallurgical bond is formed
Data Source
AI summary
A novel bicycle frameset created from a novel frame assembly and a novel fork assembly, where the components of the frame are joined together via the friction stir welding of the tubular components to partial bracket members and where the joining of the partial bracket members via friction stir welding rigidly connects the tubular components to create the frame, and where the components of the fork are joined together via friction stir welding of tubular components to a fork crown, and where the fork and frame combine form the frameset.