Drive Chain Link Geometry for Smoother Chainring Engagement
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Solution Overview
Problem
Existing drive chain systems with alternating inner and outer links face challenges in achieving smooth engagement between chain links and chainrings due to insufficient protrusions, leading to noise and potential chain misalignment.
Innovation Solution
The drive chain system incorporates a chain with inner and outer links where the outer link plates have protrusions that reduce the distance between their inner surfaces, allowing for improved guidance of teeth on the chainring, with tapered and laterally curved teeth that easily engage and stabilize within the link plates, reducing noise and misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If protrusions are added to outer link plates to reduce distance between inner surfaces, then guidance of teeth and noise reduction is improved, but chain structure complexity increases
Solution Approach 1:
The patent applies local quality by adding protrusions only to specific areas of the outer link plates where they are needed for tooth guidance, rather than modifying the entire chain structure. The protrusions are strategically positioned on the inner surfaces of outer link plates to create engagement points for the chainring teeth, providing localized improvement in guidance without requiring complete redesign of the chain architecture.
Solution Approach 2:
The chain structure is segmented into inner link plates and outer link plates with distinct functions. The outer link plates are further segmented by adding protrusions that create discrete engagement points. This segmentation allows the tooth guidance function to be separated from the basic chain link structure, enabling independent optimization of each component.
2Ease of operation
If protrusions are made larger to improve tooth engagement, then engagement smoothness is improved, but the gap between link plates decreases making engagement more difficult
Solution Approach 1:
The patent applies parameter changes by carefully controlling the dimensions of the protrusions relative to the gap between link plates. The protrusions are designed with specific height and width parameters that allow them to provide adequate tooth guidance while maintaining sufficient gap for tooth insertion. The parameters are optimized so that the protrusion height is less than the gap distance, and the protrusion width is proportionate to the tooth dimensions.
3Ease of operation
If teeth are tapered to facilitate engagement with protrusions, then engagement ease is improved, but lateral guidance stability may be reduced
Solution Approach 1:
The patent applies dynamics by designing teeth with a tapered shape that transitions from a wider base to a narrower tip. This dynamic geometry allows the tooth to easily insert between the protrusions during engagement, then provides adequate lateral guidance once engaged. The taper ratio is specifically chosen to balance insertion ease with post-engagement stability.
Data Source
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AI summary
The present invention relates to a drive chain system comprising a chain with 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) 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) comprise protrusions (36) in the area between the adjacent inner link plates (18). The system comprises a chainring (12) with a plurality of teeth (34), which teeth (34) taper laterally towards their respective tip (50).