Solid Lubricating Coating for Engine Screw Seizure Resistance
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Solution Overview
Problem
Conventional lubricating coatings for internal combustion engine components, particularly thread portions, often fail to provide sufficient seizure resistance at high temperatures due to flowability issues and deposition problems, leading to impaired workability and reduced bonding performance.
Innovation Solution
A lubricating coating composition comprising an organosilicon polymer with a polycarbosilane skeleton cross-linked by a metallic element, combined with solid lubricants like molybdenum disulfide, boron nitride, and graphite, applied as a solid film to prevent seizure and maintain heat resistance up to 800°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a paste-like lubricant is applied to thread portions, then seizure resistance is improved, but the lubricant flows out from the screw engaged region and insufficient amount remains
Solution Approach 1:
The invention changes the physical state parameter of the lubricant from paste-like to solid coating film. This parameter change eliminates the flowability issue that causes lubricant to drip out during tightening operations, while maintaining effective seizure resistance through the solid film formation on the threaded portions.
Solution Approach 2:
The invention utilizes phase transition by applying a lubricating coating composition that forms a solid coating film upon drying or heating, rather than relying on paste-like lubricants that remain in plastic state. This phase change from liquid/paste to solid ensures the lubricant stays in place during assembly operations.
2Reliability
If an oil-base lubricant is used, then lubrication is provided, but flowability increases as temperature rises causing sagging of the lubricant
Solution Approach 1:
The invention changes the temperature stability parameter by transitioning from oil-base lubricants to solid lubricant-based coating films. Solid lubricants maintain their physical properties at high temperatures (500-800°C) where oil-base lubricants would soften and sag, ensuring consistent seizure resistance across the temperature range.
Solution Approach 2:
The invention employs composite material structure combining solid lubricants (such as molybdenum disulfide, graphite, or boron nitride) with binder resins to create a coating film that provides both lubrication and high-temperature stability, overcoming the limitations of pure oil-base lubricants.
3Reliability
If a high-flow lubricant is used to ensure lubrication, then seizure resistance is improved, but deposition of the lubricant around working sites occurs impairing workability
Solution Approach 1:
The invention changes the flow characteristics parameter from high-flow to zero-flow by using solid coating films instead of liquid or paste lubricants. This eliminates the deposition problem around working sites while maintaining effective lubrication through the solid film on the threaded portions.
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 solid coating film exhibits excellent seizure resistance and workability by preventing flow and deposition, maintaining lubrication performance and bonding strength even at high temperatures, with optimal solid lubricant ratios ensuring effective seizure prevention.
Implementation Method 1
a solid lubricant which is composed of at least one member selected from among molybdenum disulfide, boron nitride, graphite, and mica
Implementation Method 2
an organosilicon polymer having a polycarbosilane skeleton cross-linked by a metallic element
Data Source
Figure 1
Figure 2~3
AI summary
To provide a lubricating coating composition which has excellent workability and which exhibits excellent seizure resistance, and an internal combustion engine attachment component, which has a solid coating film formed through application of the lubricating coating composition. A solid coating film 41 is formed on a surface of a screw member 25 of a temperature sensor 1, serving as an internal combustion engine attachment component, by use of a lubricating coating composition containing, as solid ingredients for forming the coating film 41, an organosilicon polymer having a polycarbosilane skeleton cross-linked by a metallic element, and a solid lubricant composed of at least one member selected from among molybdenum disulfide, boron nitride, graphite, and mica, and an organic solvent serving as the solvent for the solid ingredients. By virtue of the coating film 41, high seizure resistance can be attained.