Bicycle Eccentric Pulley Wheel for Derailleur Upgrade
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing bicycle pulley systems require replacement of the entire rear derailleur pulley set when increasing the size of the pulley wheel, leading to complexity in the replacement process and significant material waste.
Innovation Solution
A bicycle eccentric pulley wheel design that includes a chainring, a bearing, and side covers with an eccentric hole, allowing for the enlargement of the pulley wheel without replacing the entire pulley set, and featuring a hollow disk side cover with an annular flange and a serrated or ridged eccentric hole for enhanced fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of the rear derailleur pulley wheel is increased to improve chain passage smoothness and shifting performance, then the shifting performance is improved, but the original derailleur cage and rear derailleur hanger become incompatible, requiring replacement of the entire pulley set which adds complexity and causes material waste
Solution Approach 1:
The pulley wheel is divided into separable components: the chainring, the bearing, and the side cover assembly. This segmentation allows the side cover with the eccentric hole to be replaced independently from the bearing and chainring, enabling users to upgrade pulley size without replacing the entire pulley set. The modular design resolves the contradiction by making the replacement process simpler while maintaining improved shifting performance.
Solution Approach 2:
The invention introduces an eccentric hole in the side cover that is offset from the center, creating an eccentric structure. This dimensional change allows the pulley wheel to be mounted on the original bearing and cage while achieving a larger effective pulley diameter. The eccentric design enables the chain to engage at a different radius, improving shifting performance without requiring complete replacement of the derailleur components.
2Duration of action of stationary object
If the size of the rear derailleur pulley wheel is increased to reduce wear and tear, then the durability is improved, but the entire pulley set must be replaced which causes significant material waste
Solution Approach 1:
The invention extracts the wear-resistant and adjustable functionality into a separate replaceable side cover component with an eccentric hole. This allows the side cover to be optimized for durability and replaced independently when worn, while the bearing and chainring can be retained. This extraction principle resolves the contradiction by enabling selective replacement that reduces material waste while maintaining improved durability.
Solution Approach 2:
The modular design allows users to discard only the worn side cover component while recovering and reusing the bearing, chainring, and other intact components. This selective discarding approach significantly reduces material waste compared to replacing the entire pulley set, while still achieving the durability benefits of a larger, optimized pulley design.
3Ease of operation
If a larger pulley wheel is designed to improve chain engagement, then the chain passage smoothness is improved, but incompatibility with original derailleur cage and hanger requires complete replacement
Solution Approach 1:
The side cover with the eccentric hole is designed to nest around the original bearing, creating a nested structure where the new eccentric component integrates with the existing bearing and cage. This nesting approach allows the larger pulley wheel design to be compatible with original derailleur components, resolving the contradiction by enabling chain passage improvement while maintaining adaptability to the original system.
Solution Approach 2:
The side cover acts as an intermediary component that bridges the original bearing/cage system and the larger pulley wheel requirement. The eccentric hole in the side cover mediates between the fixed bearing mounting points and the desired larger chain engagement radius, allowing improved chain passage smoothness while maintaining compatibility with the original derailleur components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the enlargement of the pulley wheel to improve shifting performance and reduce wear and tear, while minimizing material usage and simplifying the replacement process, thus enhancing the riding experience and reducing costs.
Implementation Method 1
the inner ring can rotate relative to the outer ring
Data Source
AI summary
A bicycle eccentric pulley wheel having a chainring, a bearing, and at least one side cover. The chainring is rotatably mounted on the bearing, and the side cover is fixed to the bearing. The side cover is a hollow disk and includes an annular flange formed in an axial direction. The inner side of the annular flange includes a raised portion facing towards a center. The raised portion includes an eccentric hole, which is offset from the center defined by the side cover.