Fibrous Spoke Wheel with Aerodynamic Jacket
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Solution Overview
Problem
Bicycle and motorcycle wheels face a tradeoff between being lightweight and strong due to the limitations of steel spokes, which are heavy and prone to weakening when bent, and existing solutions like multifilament and liquid crystal fiber spokes face manufacturing challenges with alignment and increased costs.
Innovation Solution
The use of fibrous material spokes that are lighter, stronger, flexible, and resilient, allowing them to bend without damage, with an aerodynamic jacket to reduce drag, and requiring fewer spokes for superior strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If steel spokes are made thinner to reduce weight, then the weight decreases, but the strength decreases
Solution Approach 1:
The patent applies composite materials by combining carbon fibers with a resin matrix to create spoke components. The carbon fiber provides high strength-to-weight ratio, while the resin matrix binds the fibers and distributes loads. This composite structure achieves both lightweight and high strength properties that cannot be obtained with traditional steel alone.
Solution Approach 2:
The patent implements local quality by varying the fiber orientation and density in different regions of the spoke. The carbon fibers are arranged with specific orientations (e.g., 0°, 45°, 90° plies) in different layers to optimize strength in specific directions where loads are applied, rather than using uniform material properties throughout the entire spoke.
2Strength
If steel spokes are made thicker to increase strength, then the strength increases, but the weight increases
Solution Approach 1:
The patent uses carbon fiber composite materials that inherently provide superior strength-to-weight ratio compared to steel. The carbon fiber structure allows achieving higher strength without proportional weight increase, as carbon fiber has both high tensile strength and low density.
Solution Approach 2:
The patent segments the spoke into multiple layers with different fiber orientations (e.g., inner layer with 0° fibers for axial strength, outer layers with 45° and 90° fibers for lateral and radial strength). This segmentation allows optimizing strength in specific directions without adding unnecessary material and weight throughout the entire spoke.
3Weight of moving object
If multifilament spokes are used to reduce weight, then the weight decreases, but manufacturing alignment becomes more difficult
Solution Approach 1:
The patent uses a flexible resin matrix that encapsulates and protects the carbon fiber bundles. This matrix allows the fiber structure to be more tolerant of manufacturing variations and alignment tolerances, as the resin can distribute loads and accommodate minor misalignments without causing failure.
Solution Approach 2:
The patent employs a multi-layer construction with different fiber orientations that dynamically adapts to various loading conditions. This dynamic structure compensates for manufacturing variations by redistributing stresses through different fiber layers, reducing the impact of alignment imperfections.
4Weight of moving object
If liquid crystal fiber spokes are used to reduce weight, then the weight decreases, but assembly costs increase due to alignment requirements
Solution Approach 1:
The resin matrix acts as a flexible shell that encapsulates the fiber structure, providing a more forgiving interface for connection to the wheel hub and rim. This flexible encapsulation reduces the precision required for alignment during assembly, simplifying the overall assembly process while maintaining structural integrity.
5Strength
If traditional steel spokes are used, then strength is adequate, but drag increases and weight increases
Solution Approach 1:
The patent applies aerodynamic fairings or covers over the spoke components that are designed to streamline airflow. These fairings reduce turbulence and drag by smoothing the flow of air over the spoke structure, thereby reducing energy loss while maintaining the structural integrity of the carbon fiber spokes.
Data Source
AI summary
A wheel with flexible spokes, including a rim and hub, and spokes between the rim and hub made of fibrous material that causes the spokes to be both lighter in weight and stronger than comparable steel spokes. The spokes are also flexible and resilient such that they can bend while retaining their integrity and strength.