Bicycle Chain Outer Link Protrusions for Quieter Chainring Meshing
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Solution Overview
Problem
Existing bicycle chains with alternating inner and outer links face challenges in smooth engagement with chainrings due to insufficient protrusions, leading to noise and poor guidance, as the gap between link plates is too narrow for effective tooth engagement.
Innovation Solution
The chain design features protrusions on the inner surfaces of outer link plates, reducing the distance between these surfaces and enhancing the guidance of teeth on the chainring, with optimized dimensions and shapes to improve engagement and reduce noise, while maintaining structural integrity and weight efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If protrusions are added to reduce clearance between teeth and chain links, then guidance and noise reduction are improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by adding protrusions only at specific locations on the inner surfaces of outer link plates where teeth engagement occurs. These localized protrusions provide enhanced guidance and noise reduction exactly where needed, while leaving the rest of the chain structure simple and unchanged. This resolves the contradiction by improving local engagement quality without globally complicating the chain design.
2Ease of operation
If protrusions are made larger to improve guidance, then engagement smoothness increases, but chain width and weight increase
Solution Approach 1:
The patent applies parameter changes by optimizing the protrusion dimensions to specific ranges: the protrusion diameter is set between 0.4-0.8mm and the height between 0.2-0.5mm. These carefully selected parameters provide sufficient guidance and smooth engagement while minimizing the increase in chain width and weight. The parameter optimization resolves the contradiction by finding the optimal balance between engagement quality and dimensional constraints.
Data Source
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AI summary
The present invention relates to a chain (10) comprising an alternating succession of inner chain links (14) and outer chain links (16), each inner chain link (14) having a pair of inner link plates (18) contacting the lateral faces of two rollers (30) and each outer chain link (16) having a pair of two outer link plates (20, 20') contacting the inner link plates (18) of adjacent inner chain links (14). A pin (32) connects two outer link plates (20) and two inner link plates (18) and a roller (30), wherein the inner surfaces (26) of a pair of opposite outer link plates (20, 20') comprise protrusions (36) in the area between the adjacent inner link plates (18). The circumference and/or diameter of the protrusion is at least 60% and/or maximum 140% the circumference and/or diameter of the eyes (60) of the outer link plate.