Cassette Toothed Wheel Assembly for Lightweight Torque Transfer
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Solution Overview
Problem
Existing toothed wheel assemblies for bicycle cassettes are not lightweight enough without compromising mechanical features, as material cannot be removed from structural components without affecting functionality.
Innovation Solution
The toothed wheel assembly reduces material from non-structural radially inner edges and optimizes connection body placement using spokes to minimize weight while maintaining structural integrity, allowing for further reduction in weight without compromising torque transfer or plastic deformation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If material is removed from toothed wheels to reduce weight, then weight decreases, but structural strength and resistance to plastic deformation deteriorate
Solution Approach 1:
The toothed wheel is divided into functional zones: the radially outer edge retains full thickness for structural strength and chain engagement, while the radially inner edge has reduced thickness since it does not interact with the chain. This segmentation allows weight reduction in non-critical areas while maintaining strength where needed.
Solution Approach 2:
Different radial portions of the toothed wheel have different thicknesses to match their functional requirements. The radially outer edge maintains greater thickness for structural integrity and chain interaction, while the radially inner edge has reduced thickness for weight reduction, creating local quality variations optimized for each zone's specific function.
2Strength
If connection bodies are added to connect toothed wheels axially, then structural integrity improves, but weight increases
Solution Approach 1:
The connection bodies are integrated with the spokes of the toothed wheel assembly. The spokes serve dual functions: providing structural support for the toothed wheels and acting as connection bodies to axially space and connect adjacent toothed wheels. This merging eliminates separate connection components and reduces overall weight.
Solution Approach 2:
The spokes perform multiple functions simultaneously: they provide radial support for the toothed wheels, enable rotational movement, and act as axially-extending connection bodies to connect adjacent toothed wheels. This multi-functionality reduces the need for additional dedicated connection components, thereby reducing weight.
Data Source
AI summary
The invention relates to a toothed wheel assembly for a cassette having a first toothed wheel and a second toothed wheel that are concentric. The second tooth wheel has a greater number of teeth than the first toothed wheel; a radially inner cylindrical portion to engage a sprocket support body; a plurality of spokes comprising respective first constraining portions to the first toothed wheel and second constraining portions to the radially inner cylindrical portion; and a plurality of connection bodies that connect the first. The second toothed wheel has an axially-extending portion with at least one pair of spokes having connection bodies that include axially-extending portions in the circumferential direction and at least partially contained in the minimum circumferential extension a respective spoke.