Two-Wheeler Chain Coating for Low-Wear Drive Assemblies
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Solution Overview
Problem
High-performance two-wheeler chains require frequent lubrication and maintenance, which is inconvenient, costly, and affects aesthetic appearance due to wear and contamination issues, especially with road dirt and moisture.
Innovation Solution
A drive arrangement with a closed chain coated with pure diamond-like carbon (ta-C) on sleeves and rollers, maintaining specific surface roughness and layer thickness, combined with a friction-reducing coating on sealing rings, reduces friction and wear, allowing for extended maintenance intervals without additional lubrication efforts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional chains are used without special coatings, then the structure is simple and manufacturing is easy, but frictional wear is high requiring frequent lubrication and maintenance
Solution Approach 1:
The patent applies a composite material structure by coating the outer surfaces of sleeves and rollers with diamond-like carbon (ta-C). This creates a composite system where the steel base material provides structural strength while the ta-C coating provides wear and friction resistance. The coating layer thickness is controlled at 0.5-5 μm to optimize performance while maintaining simplicity.
Solution Approach 2:
The patent changes the surface parameters of the chain components by applying ta-C coating with specific properties: hardness of 70-100 GPa, friction coefficient of 0.05-0.15, and controlled surface roughness (Ra: 0.03-0.2 μm, Rz: 0.3-2 μm). These parameter changes significantly reduce frictional wear and eliminate the need for frequent lubrication.
2Reliability
If frequent lubrication is applied to reduce wear, then frictional wear is reduced, but maintenance effort and time increase significantly
Solution Approach 1:
The ta-C coated chain components provide self-lubricating properties due to the low friction coefficient (0.05-0.15) of the coating. The smooth surface finish and inherent lubricity of diamond-like carbon reduce friction without requiring external lubrication, allowing the chain to maintain low wear for extended periods without maintenance intervention.
Solution Approach 2:
The ta-C coating provides continuous wear protection throughout the service life of the chain components. The coating maintains its protective properties continuously without interruption from lubrication cycles, ensuring consistent low-friction operation and extended maintenance intervals of 10,000 km or more.
3Reliability
If lubricant is applied frequently to maintain chain function, then wear is reduced, but aesthetic appearance deteriorates due to contamination and soiling
Solution Approach 1:
The ta-C coated chain components provide self-lubricating properties due to the low friction coefficient (0.05-0.15) of the coating. The smooth surface finish and inherent lubricity of diamond-like carbon reduce friction without requiring external lubrication, allowing the chain to maintain low wear for extended periods without maintenance intervention.
Solution Approach 2:
The ta-C coating provides continuous wear protection throughout the service life of the chain components. The coating maintains its protective properties continuously without interruption from lubrication cycles, ensuring consistent low-friction operation and extended maintenance intervals of 10,000 km or more.
4Reliability
If sprayed lubricant is used for short intervals, then some lubrication effect is achieved, but centrifugal force flings off the lubricant causing contamination
Solution Approach 1:
The ta-C coated chain components provide self-lubricating properties due to the low friction coefficient (0.05-0.15) of the coating. The smooth surface finish and inherent lubricity of diamond-like carbon reduce friction without requiring external lubrication, allowing the chain to maintain low wear for extended periods without maintenance intervention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces frictional wear and maintenance needs, improving the efficiency and service life of two-wheeler components, reducing lubricant consumption, and enhancing the aesthetic appearance by eliminating the need for frequent relubrication, with maintenance intervals extended to 10,000 km or more.
Implementation Method 1
The ta-C coatings are to be formed using a PVD process
Implementation Method 2
a layer of pure ta-C. The coatings contain no other chemical elements besides carbon
Data Source
AI summary
The invention relates to a drive assembly for a two-wheeled vehicle, wherein a closed chain is guided around a drive pinion and a sprocket for the output. The chain is formed by pins, on each of which a bush rotatable about the center longitudinal axis of the pin in question is arranged, a roller being provided on each bush, which roller is arranged for rotation around the bush and has play, and the pins being connected to each other at two opposite end faces by means of plates. The outer surface of each of the bushes and of each of the rollers is coated with a coating of pure ta-C, and there are no further chemical elements in the coatings except for the unavoidable trace elements resulting from production in a PVD method by means of which the coatings have been formed. An Ra roughness of between 0.03 µm and 0.2 µm and/or an Rz roughness of between 0.3 µm and 2 µm is adhered to at the surface of the coatings. The surfaces of the pinion and of the sprocket that are in contact with the rollers of the chain do not have a coating of diamond-like carbon.