Chain Link Waist Geometry for Stable Meshing and Fast Shifting
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Solution Overview
Problem
Conventional bike, scooter, and motorcycle chains experience noise and instability due to wobbling and misalignment when rotating, and sluggish gear changes due to mismatched meshing spaces between chain links and pulleys.
Innovation Solution
A chain design featuring alternating inner and outer link units with specific waist sections and openings, and a connecting rod unit, forming a closed-loop mechanism that stabilizes meshing and facilitates smooth gear changes by ensuring proper alignment and tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the first opening of the outer meshing space is made larger to facilitate chain movement, then the ease of operation is improved, but the chain becomes unstable and wobbles during rotation
Solution Approach 1:
The outer chain plate is designed with non-uniform thickness: the first portion (near the first opening) has greater thickness than the second portion (near the second opening). This local quality variation allows the first opening to be larger for easy chain engagement while the thicker first portion provides lateral support to prevent chain wobble during rotation.
2Ease of manufacture
If the chain structure is simplified to reduce complexity, then the ease of manufacture is improved, but the ability to prevent chain wobble is reduced
Solution Approach 1:
Instead of adding complex external components, the solution modifies the local geometry of the outer chain plate by varying its thickness in different regions. This maintains manufacturing simplicity while achieving the dual function of easy chain engagement and wobble prevention.
3Adaptability or versatility
If the outer meshing space width is increased to accommodate guide pulley movement, then the adaptability is improved, but the chain responds sluggishly during gear changes
Solution Approach 1:
The variable thickness design allows the outer meshing space to have appropriate width for guide pulley accommodation while the thicker first portion of the outer chain plate provides lateral rigidity. This ensures rapid chain response during gear changes without compromising guide pulley compatibility.
Data Source
AI summary
A transmission mechanism includes a chain. The chain includes a plurality of inner link units and a plurality of outer link units. Each of the inner link units includes two inner chain plates. Each of the inner chain plates has an inner waist section. At least one of the outer link units includes two outer chain plates. Each of the outer chain plates has an outer waist section that has a protruding part and a recessed part. A distance between the inner waist sections of each of the inner link units is smaller than a distance between the protruding parts of the outer chain plates of the at least one of the outer link units, and is equal to or smaller than a distance between the recessed parts of the at least one of the outer link units.