Drive Chain and Offset Sprocket Teeth for Smoother Shifting
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Solution Overview
Problem
Drive chain systems with alternating inner and outer links face challenges in smooth engagement with sprocket teeth during shifting operations due to insufficient gap width between link plates, leading to compromised shifting performance and increased noise.
Innovation Solution
The drive chain system incorporates sprocket teeth with laterally offset tips and varying angles of taper and inclination, combined with protrusions on outer link plates, to enhance the engagement and guidance of the chain during shifting, allowing for improved shifting performance and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If protrusions are added to outer link plates to improve chain guidance, then chain guidance is improved, but shifting performance deteriorates due to insufficient gap width
Solution Approach 1:
The patent applies local quality by creating protrusions only on specific outer link plates that engage with chainring teeth, while leaving other outer link plates without protrusions. This localized approach allows improved guidance where needed while maintaining sufficient gap width for shifting operations on other links.
Solution Approach 2:
The chain is segmented into different types of outer link plates - some with protrusions for guidance and some without protrusions for shifting. This segmentation allows the chain to perform different functions at different locations, resolving the contradiction between guidance and shifting performance.
2Manufacturing precision
If chain links have smaller gap width for better engagement, then engagement precision is improved, but shifting capability deteriorates due to insufficient clearance
Solution Approach 1:
The chain is divided into different types of links with different gap widths. Inner chain links have smaller gaps for precise engagement, while outer chain links have larger gaps to accommodate shifting movements. This segmentation allows the chain to simultaneously achieve precise engagement and adequate shifting capability.
Solution Approach 2:
Different portions of the chain have different gap widths tailored to their specific functions. The local quality approach ensures that engagement precision is optimized where needed while maintaining shifting capability where required.
Data Source
AI summary
A drive chain system having a chain with an alternating succession of inner chain links and outer chain links, each inner chain link having a pair of inner link plates and each outer chain link having a pair of two outer link plates contacting the inner link plates of adjacent inner chain links. A pin connects two outer link plates and two inner link plates, wherein the inner surfaces of a pair of opposite outer link plates has protrusions in the area between the adjacent inner link plates. The system has a rear cassette with a multitude of sprockets with a plurality of sprocket teeth, wherein the cassette has sprocket teeth of different tooth types, the teeth of at least one tooth type having a tip laterally offset from the centerplane.