Fiber Composite Fork Column and Aluminum Crown Segmentation
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Solution Overview
Problem
Bicycle forks made from traditional materials like steel and aluminum are heavy, while fiber composite forks face inaccuracies in manufacturing, leading to increased weight and reduced stability due to unnecessary fiber layers.
Innovation Solution
A fork component with a shaft tube unit made from fiber composite material, comprising a fork column and fork crown connected in a torsion-proof manner, allowing for a lighter and more stable design by reducing the number of fiber layers and using a core material for weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If one-piece fiber composite fork production is used, then weight is reduced, but manufacturing precision deteriorates leading to fiber mat displacement and increased weight
Solution Approach 1:
The fork is divided into two separate components: the fork column (made of fiber composite material) and the fork crown (made of aluminum). This segmentation allows each component to be manufactured separately with high precision, avoiding fiber mat displacement issues while maintaining weight reduction benefits. The fork column can use optimized fiber layup without the complexity of one-piece production.
Solution Approach 2:
The fork column and fork crown are connected through a form-fitting connection with interference fit and adhesive bonding. This merging of two separately manufactured components creates a unified fork structure that combines the lightweight benefits of fiber composite material with the manufacturing precision of aluminum, resolving the contradiction between weight reduction and manufacturing accuracy.
2Reliability
If greater wall thicknesses are used at connection points to ensure force transmission, then reliability is improved, but weight increases
Solution Approach 1:
The fork column uses fiber composite material (carbon fiber reinforced plastic) which provides high strength-to-weight ratio. This allows thin-walled construction while maintaining sufficient force transmission capability. The anisotropic properties of composite materials enable optimized fiber orientation to handle specific load directions efficiently.
Solution Approach 2:
The connection between fork column and fork crown is designed with preliminary interference fit and adhesive application. The interference fit creates initial mechanical interlocking, and the adhesive provides additional bonding strength. This preliminary preparation ensures reliable force transmission without requiring excessive wall thickness.
3Stability of the object's composition
If more fiber layers are used to compensate for manufacturing inaccuracies, then stability is improved, but weight increases
Solution Approach 1:
By separating the fork into column and crown components, each can be manufactured with appropriate fiber layer optimization. The fork column uses precisely controlled fiber layup for stability, while the aluminum crown provides structural support. This segmentation eliminates the need for excessive fiber layers to compensate for one-piece manufacturing variations.
Solution Approach 2:
The design changes the material parameter from uniform fiber composite throughout to a hybrid construction: fiber composite fork column for optimized stability with minimal layers, and aluminum fork crown for structural support. This parameter change allows stability to be achieved with fewer fiber layers, reducing weight.
Data Source
Figure 1~2
Figure 3~5
Figure 5a~5d
AI summary
Fork component (1) for a vehicle powered at least partially by muscle power, and in particular a bicycle (100), comprising a steerer tube assembly (3) made of fiber composite material (2). The steerer tube assembly (3) comprises a steerer tube (4) and a fork crown (5), which are designed as two separate parts that are positively connected to each other to form the steerer tube assembly (3).