Hollow Composite Bicycle Rim with Automated Fiber Bundle Layup
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Solution Overview
Problem
Existing methods for manufacturing fiber-reinforced composite bicycle rims face limitations in stability and strength due to short fiber lengths, leading to increased weight when thicker walls are used, and high costs and labor intensity with prepreg methods.
Innovation Solution
A method involving the use of a fiber structure formed by attaching fiber bundles to a carrier layer, guided and secured mechanically, with a fiber binder to maintain shape, and a filling unit to create a hollow chamber, allowing for automated production with reduced parts and manual labor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If short fibers are used in injection molding, then automated production is achieved, but stability and strength are limited
Solution Approach 1:
The fiber reinforcement is segmented into two distinct components: a base fiber layer providing general reinforcement and additional fiber structures providing targeted reinforcement in specific areas. This segmentation allows automated production of the base layer while enabling selective manual placement of high-strength fiber structures where needed, resolving the contradiction between automation and strength.
Solution Approach 2:
The invention combines different fiber structures (base fiber layer from injection molding with additional fiber structures) to create a composite reinforcement system. This composite approach integrates the advantages of automated short-fiber production with the strength benefits of longer, strategically placed fibers, achieving both automation and high strength.
2Strength
If wall thickness is increased to improve strength, then stability improves, but weight increases
Solution Approach 1:
Instead of uniformly increasing wall thickness throughout the rim, the invention applies additional fiber structures only in specific areas requiring enhanced strength and stability. This local reinforcement approach improves structural performance where needed while minimizing overall material usage and weight increase.
3Strength
If prepregs are used to achieve suitable wall thickness and high quality, then strength improves, but cost and manual labor increase
Solution Approach 1:
The manufacturing process is segmented into an automated injection molding stage for the base fiber layer and a selective manual stage for adding specific fiber structures only where needed. This reduces the overall manual labor compared to traditional prepreg methods that require draping numerous individual fabric pieces, while maintaining high quality and strength.
Solution Approach 2:
The invention merges the advantages of automated injection molding (cost-effective, high productivity) with selective manual fiber placement (high strength where needed). This hybrid approach combines the benefits of both methods while minimizing their respective disadvantages, reducing overall cost and manual labor compared to pure prepreg processes.
Data Source
Figure 1~2
Figure 3a~3d
Figure 4a~5
AI summary
Bicycle rim (50) and method for manufacturing a bicycle rim (50) and bicycle rim (50), wherein the bicycle rim (50) comprises a rim body (1) with at least one cavity (2) integrated therein. The cavity (2) is enclosed all around by a surrounding component wall (4). The rim body (1) extends in a rim plane (52) over a circumference of 360° transverse to its axis of rotation (53). The cavity (2) forms a hollow chamber (3) in the rim body (1). Several component walls (4) are formed, wherein the component walls comprise two lateral rim flanks (54, 55), a radially inner rim base (55), and a radially outer rim bed (56), which delimit the hollow chamber (3). A supporting structure (5) of the rim body (1) is formed by at least one fiber structure (11-14).To produce the fiber structure (11-14), a fiber bundle (15) is attached to a carrier layer (20) with thread elements (19) and guided back and forth on the carrier layer (20) to form a base fiber layer (21) of the fiber structure (11-14). The fiber structure (11-14) is draped in a mold (40). A filling unit (55) is placed in the mold (40) so that the filling unit (45) maintains the volume for the cavity (2) and the cavity (2) is surrounded by the component wall (4).