Chain Link Geometry for Stable Meshing and Fast Gear Shifts
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Solution Overview
Problem
Conventional bike, scooter, and motorcycle chains experience noise and instability due to wobbling and sluggish gear changes, primarily caused by mismatched meshing spaces and pulley teeth sizes, leading to inefficient gear shifting and potential chain loss.
Innovation Solution
A chain mechanism featuring alternating inner and outer link units with specifically designed waist sections, protruding, and recessed parts, along with connecting rods, forms meshing spaces that accommodate teeth of varying sizes, ensuring stable meshing and smooth gear transitions by maintaining optimal tension and preventing wobbling.
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 chain can move more freely, but the chain becomes unstable and wobbles perpendicular to the rotating direction
Solution Approach 1:
The outer meshing space is designed with non-uniform width: the first opening (proximal to chainwheel) has a larger width for easy chain engagement, while the second opening (distal to chainwheel) has a smaller width to prevent excessive chain movement. This local variation in dimensional quality resolves the contradiction between movement freedom and stability.
2Ease of operation
If the chain meshing space width is increased to allow smooth tooth entry, then gear shifting becomes easier, but the chain cannot be instantaneously moved by the guide pulley
Solution Approach 1:
The outer meshing space features a width gradient along the chain movement direction, with the first opening being wider to facilitate smooth tooth entry during gear shifting, and the second opening being narrower to enable rapid chain response to guide pulley action. This localized dimensional variation resolves the contradiction between shifting smoothness and response speed.
3Object-generated harmful factors
If flange portions are added to prevent chain from striking adjacent chainwheels, then noise is reduced, but the chain structure becomes more complex
Solution Approach 1:
The flange portion is integrated directly into the outer chain plate structure, merging the noise-reduction function with the existing chain component rather than adding a separate element. This combination reduces noise by preventing chain from striking adjacent chainwheels while minimizing structural complexity.
4Ease of operation
If protruding portions are added to facilitate tooth entry into meshing spaces, then gear meshing becomes smoother, but the manufacturing complexity increases
Solution Approach 1:
The protruding portion is designed as a localized feature on the outer chain plate, creating a width variation in the outer meshing space that facilitates smooth tooth entry. This local modification achieves improved gear meshing while maintaining relatively simple manufacturing by modifying only specific regions of existing components rather than redesigning the entire chain structure.
Data Source
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AI summary
A transmission mechanism (2) includes a chain (3) that includes a plurality of inner link units (4) and a plurality of outer link units (5). Each of the inner link units (4) includes two inner chain plates (41) each of which has an inner waist section (43). At least one of the outer link units (5) includes two outer chain plates (5) each of which has an outer waist section (53) that has a protruding part (56) and a recessed part (57). A distance between the inner waist sections (43) of each of the inner link units (4) is smaller than a distance between the protruding parts (56) of the outer chain plates (51) of the at least one of the outer link units (5), and is equal to or smaller than a distance between the recessed parts (57) of the at least one of the outer link units (5).