Bicycle Chain Chamfer Geometry for Smoother Sprocket Shifting
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Solution Overview
Problem
Bicycle chains experience inefficiencies in shifting performance due to design limitations, leading to suboptimal engagement with sprockets and chain-holding capabilities.
Innovation Solution
The bicycle chain design incorporates specific geometries and chamfers on inner and outer link plates, including a first chamfer that improves shifting performance by optimizing the engagement with sprockets and enhancing chain-holding through precise radial distances and chamfer configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional chain design is used, then manufacturing is simpler, but shifting performance is insufficient
Solution Approach 1:
The patent applies local quality by introducing a chamfer specifically at the inner-link end edge where it contacts the sprocket tooth. This localized geometric modification improves shifting performance at the critical engagement point without complicating the overall chain structure. The chamfer creates a smooth transition surface that guides the chain onto the sprocket during shifting operations.
Solution Approach 2:
The patent employs asymmetry by designing the inner-link end edge with a chamfer that is not symmetrically distributed. The chamfer is positioned specifically on one side of the link plate end edge to optimize contact with the sprocket tooth during the shifting motion. This asymmetric feature enhances the directional engagement between chain and sprocket, improving shifting performance.
2Reliability
If conventional chain design is used, then structure is simpler, but chain-holding capability is suboptimal
Solution Approach 1:
The patent applies local quality by modifying specific geometric parameters of the link plate, including the chamfer angle and radius at the inner-link end edge. These localized geometric optimizations enhance the chain's ability to hold onto the sprocket teeth during operation, improving chain-holding capability without requiring a complete redesign of the entire link plate structure.
3Productivity
If conventional chain design is used, then engagement with sprockets is less efficient, but manufacturing is easier
Solution Approach 1:
The patent applies parameter changes by optimizing the chamfer geometry parameters, specifically the chamfer angle and radius at the inner-link end edge. By carefully selecting and adjusting these geometric parameters, the patent improves the engagement efficiency between the chain and sprocket during shifting operations. The optimized parameters facilitate smoother chain-sprocket interaction while remaining manufacturable with standard precision capabilities.
Data Source
AI summary
A bicycle chain comprises a first inner link plate and a second inner link plate. The first inner link plate comprises a first inner-link end portion, a second inner-link end portion, and a first inner-link intermediate portion. The second inner link plate comprises a third inner-link end portion, a fourth inner-link end portion, and a second inner-link intermediate portion. A first inner-link end edge has a first chamfer extending about the first inner-link center axis such that a part of the first chamfer is disposed in a first circumferential area defined from a first inner-link longitudinal centerline to a first reference line when viewed in an axial direction of the first inner-link center axis. The first circumferential area is smaller than 14 degrees.