Chain Pin VCN Coating Suppresses Oxide Film Wear
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Solution Overview
Problem
Silent chains and roller chains face durability issues due to abnormal wear under severe lubrication conditions, particularly in next-generation engines where lubricant viscosity is low and load tension is increased, leading to excessive oxide film formation and wear in conventional vanadium carbide-coated pins.
Innovation Solution
A vanadium carbonitride (VCN) coating is applied to the pins, formed by a process of vanadium carbide coating followed by nitrogen permeation, which reduces nitrogen content in a gradient, suppressing excessive oxide film growth and enhancing toughness and hardness, thereby reducing wear and maintaining a mirror surface under high contact pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vanadium carbide (VC) coating is applied to the pin surface to provide high wear resistance, then the surface durability is improved, but under severe lubrication conditions the oxide film becomes excessively thick and soft, leading to increased wear
Solution Approach 1:
The invention changes the chemical composition parameters of the coating by introducing nitrogen to form vanadium carbonitride (VCN) instead of pure vanadium carbide (VC). This parameter change modifies the oxidation behavior of the coating, suppressing excessive oxide film formation while maintaining surface durability and toughness under severe lubrication conditions.
Solution Approach 2:
The invention creates a composite material structure by forming vanadium carbonitride (VCN) that combines characteristics of carbide and nitride phases. This composite structure provides both the wear resistance of carbide and the oxidation resistance of nitride, preventing excessive oxide film formation while maintaining surface durability.
2Use of energy by moving object
If the lubricant viscosity is lowered to improve fuel efficiency, then energy consumption is reduced, but the chain lubrication environment becomes severe leading to boundary lubrication conditions and abnormal wear
Solution Approach 1:
The invention applies preliminary protective action by forming a vanadium carbonitride (VCN) coating on the pin surface before the chain operates under severe lubrication conditions. This pre-applied protective layer prevents excessive oxide film formation and abnormal wear from the outset, enabling the chain to withstand boundary lubrication conditions without degradation.
Solution Approach 2:
The invention changes the coating material parameters from pure vanadium carbide to vanadium carbonitride, which has superior performance in boundary lubrication conditions. This parameter change allows the chain to maintain durability even when lubricant viscosity is lowered for improved fuel efficiency.
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 VCN coating significantly reduces wear elongation and maintains surface roughness, ensuring long-term reliability and durability of the chain even under severe conditions, improving fuel efficiency and sustainability in internal combustion engines.
Implementation Method 1
formed by a process of vanadium carbide coating followed by nitrogen permeation
Implementation Method 2
suppressing excessive oxide film growth
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
At least one member composing a chain bearing (9), e.g., a pin (2), includes a surface layer (21) comprising vanadium carbonitride (VCN) coating on a surface of a base material (20) of the one member (2). An oxide (VO) film (22) having a predetermined thickness is also formed on a surface of the surface layer (21) such that the oxide film (22) is interposed between the surface layer (21) and another member , e.g., a pin hole(3, 7), composing the bearing (9). The VO film (22) is suppressed from being formed excessively by the VCN coating even under a severe environment.