Bicycle Sprocket Module Integrating Multiple Gears for Weight Reduction
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Solution Overview
Problem
Conventional bicycle sprocket assemblies are heavy due to the need for multiple sprockets with engagement means to the freewheel body, which can result in a weak design when attempting to reduce weight.
Innovation Solution
A sprocket module comprising at least two sprockets of different diameters, where one sprocket lacks engagement means with the freewheel body and is supported by the other, allowing for reduced weight and increased strength through optimized radial portions and spacer elements, enabling efficient torque transmission and deformation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sprockets with engagement means are used in conventional assemblies, then the assembly can provide multiple gear ratios, but the weight increases significantly
Solution Approach 1:
The patent combines multiple sprockets into a single integrated module where sprockets of different diameters are fixedly coupled together. This merging approach allows multiple gear ratios to be achieved through one compact unit rather than separate heavy assemblies, resolving the contradiction between versatility and weight
Solution Approach 2:
The sprocket module is designed as a universal component that can provide multiple gear ratios through its integrated multi-diameter sprockets. This multi-functional design eliminates the need for separate single-function sprockets, reducing overall weight while maintaining adaptability across different riding conditions
2Weight of moving object
If weight is reduced by using lighter designs, then the sprocket assembly becomes lighter, but the strength and structural integrity decrease
Solution Approach 1:
By merging multiple sprockets into a single fixedly coupled module, the patent creates a unified structural unit that distributes mechanical loads across all sprockets simultaneously. This combined structure achieves superior strength-to-weight ratio compared to separate lighter sprockets, as the integrated design allows load sharing through rigid coupling
3Weight of moving object
If material usage is minimized to reduce weight, then the sprocket module becomes lighter, but deformation resistance under chain stress decreases
Solution Approach 1:
The patent applies local quality optimization by strategically positioning radial portions and spacer elements only where structurally necessary within the sprocket module. Material is concentrated in high-stress areas such as the coupling regions and load-bearing spokes, while minimizing material in low-stress zones, achieving optimal deformation resistance with reduced overall weight
Solution Approach 2:
The sprocket module employs composite construction combining multiple components (sprockets, radial portions, spacer elements) that work together to provide enhanced deformation resistance. The fixed coupling creates a composite structure where each element contributes to overall stiffness and strength, allowing weight reduction while maintaining resistance to chain-induced deformation
Data Source
AI summary
A sprocket module for a bicycle has at least two sprockets fixedly coupled one another. At least one first sprocket of the at least two sprockets comprises engagement portion to a freewheel body of a hub for a bicycle rear wheel. A second sprocket of the module lacks the engagement portion and is supported on the freewheel body through the aforementioned at least one first sprocket. The module allows strong and low-weight sprocket assemblies to be made.