Bicycle Chain Inner Plate Geometry for Low-Wear Sprocket Engagement
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Solution Overview
Problem
Bicycle drive chains with increased sprocket numbers face issues of wear and noise due to reduced dimensions and increased loads, leading to undesirable contact with sprocket components and inefficient engagement of sprocket teeth.
Innovation Solution
The design incorporates inner plates with recessed connection regions and chamfers, allowing for reliable engagement of sprocket teeth and reduced wear by minimizing axial protrusion of chain components and optimizing chamfer angles for smooth tooth passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of sprockets is increased, then the gear range and versatility are improved, but the axial spacing between sprockets is reduced causing chain components to contact adjacent sprockets undesirably
Solution Approach 1:
The patent extracts the protruding chain components (inner plates, chain pins, chain rollers) that cause interference with adjacent sprockets. By removing or reducing these protrusions, the chain is shortened axially, preventing contact with adjacent sprockets while maintaining the multi-sprocket configuration for gear versatility.
Solution Approach 2:
The patent addresses the axial interference problem by modifying dimensions in the axial direction (perpendicular to chain movement). By reducing axial protrusion rather than increasing chain width or height, the solution resolves the conflict between maintaining sprocket proximity for compactness and preventing interference.
2Adaptability or versatility
If the dimensions of chain components are reduced to accommodate closely spaced sprockets, then the adaptability to multi-sprocket arrangements is improved, but the surface pressure and wear on chain pins increase
Solution Approach 1:
The patent applies local quality by selectively modifying specific chain components (inner plates, chain pins, chain rollers) to reduce their axial protrusion. This localized dimensional reduction allows the chain to fit closely spaced sprockets while maintaining adequate dimensions in other directions to distribute loads and reduce wear.
Solution Approach 2:
The patent changes the dimensional parameters of chain components, specifically reducing axial dimensions while maintaining or adjusting radial and longitudinal dimensions. This parameter optimization allows compatibility with closely spaced sprockets while managing surface pressure and wear through balanced dimensional distribution.
3Reliability
If harder materials or surface hardening is used to counteract increased wear, then the durability is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent applies preliminary action by designing the chain components with optimized dimensions and geometries (reduced axial protrusion, modified profiles) that prevent excessive wear through proper engagement with sprockets. This preventive design approach reduces wear before it occurs, eliminating or reducing the need for additional hardening processes.
Solution Approach 2:
The patent changes geometric parameters of chain components (axial dimensions, profiles, engagement surfaces) to optimize wear characteristics. By adjusting these parameters, the chain achieves better load distribution and reduced surface pressure, providing wear resistance through design rather than requiring material hardening.
4Ease of operation
If chamfers are increased to improve tooth engagement, then the ease of operation is improved, but the axial protrusion of chain components increases causing interference with adjacent sprockets
Solution Approach 1:
The patent applies local quality by selectively applying chamfers only to specific regions of chain components where they are needed for tooth engagement, while controlling or limiting chamfer dimensions in areas that would cause axial protrusion. This localized chamfer application maintains engagement functionality while preventing interference with adjacent sprockets.
Solution Approach 2:
The patent uses partial action by applying chamfers to only the necessary portions of chain components rather than uniformly across all surfaces. This selective chamfering provides sufficient tooth engagement assistance while minimizing overall axial protrusion that would cause interference with adjacent sprockets.
Data Source
AI summary
A bicycle chain is used to transmit the drive force to at least one chain wheel and contains chain rollers and inner and outer plates which are connected to each other by means of pins. As a result of a corresponding shaping of the extremely hard inner plate, the wear on the teeth which cooperate with the inner plate can be reduced on the chain wheels or sprockets.