Ferritic Nitrocarburized Brake Surface Transfer Layer
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Solution Overview
Problem
Friction materials in vehicle braking systems face issues with wear and corrosion due to graphite flakes, which reduce the coefficient of friction and lead to pitting and roughness, compromising brake performance and durability.
Innovation Solution
Ferritic nitrocarburization of the rotational member's friction surface, combined with a transfer layer comprising materials like glass, rubber, carbon, aramid fiber, or high-temperature resin, to enhance the friction coefficient and reduce wear, while removing graphite flakes to prevent corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If graphite flakes are present in friction material, then the material provides lubrication and reduces wear, but the coefficient of friction decreases and pitting and roughness occur on the brake surface
Solution Approach 1:
The patent removes graphite flakes from the friction material composition to eliminate the harmful effects of reduced friction coefficient and surface pitting, while maintaining wear resistance through alternative material formulations and surface treatments
Solution Approach 2:
The patent applies ferritic nitrocarburization surface treatment to the rotational member, which fundamentally changes the surface properties to provide both high friction coefficient and wear resistance without relying on graphite flakes
2Duration of action of moving object
If graphite flakes are present in friction material, then the material provides lubrication, but corrosion and pitting occur on the brake surface
Solution Approach 1:
The patent extracts graphite flakes from the friction material to eliminate the corrosion and pitting they cause on brake surfaces, while maintaining protective lubrication through the ferritic nitrocarburized surface layer
Solution Approach 2:
The ferritic nitrocarburized surface layer acts as an intermediary between the friction material and the base metal, providing both lubrication and corrosion protection without the harmful effects of graphite flakes
3Force
If a transfer layer is formed on the friction surface, then the apparent friction coefficient increases to 0.33-0.36, but the surface becomes more complex with multiple material layers
Solution Approach 1:
The ferritic nitrocarburization surface treatment is applied in advance to the rotational member before friction engagement, pre-establishing the conditions for optimal transfer layer formation and high friction coefficient without requiring complex multi-layer construction
Solution Approach 2:
The patent creates a composite surface structure through ferritic nitrocarburization that combines multiple material properties (hardness, friction, wear resistance) in a single integrated surface layer, achieving high friction coefficient without the complexity of manually applied multi-layer coatings
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 increases the apparent friction coefficient to a range of 0.33 to 0.36, maintaining effective brake engagement and retarding capabilities while reducing wear and corrosion, thus improving brake performance and longevity.
Implementation Method 1
nitrocarburizing the friction surface wherein the friction surface comprises a porous oxide layer
Implementation Method 2
Frictionally engaging the friction surface with the friction material wherein the frictional engagement forms a transfer layer at the friction surface
Data Source
AI summary
One variation includes a friction material and method of manufacture thereof wherein the friction material includes a transfer layer on a ferritically nitrocarburized component, wherein the transfer layer may be fabricated from glass, rubber, carbon, aramid fiber, filler material, abrasive, or a high-temperature resin.