Layered Wet Friction Material for Clutch Pressure Cycle Durability
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Solution Overview
Problem
Friction materials used in vehicle powertrains face performance degradation and delamination under aggressive conditions due to the addition of tung oil, which increases flexibility but decreases dynamic friction coefficient and leads to higher operating temperatures, and existing materials crack or wear away under pressure cycles.
Innovation Solution
A friction material composition with a fiber material and filler material, where tung oil is saturated in one portion of the thickness and phenolic resin in another, with no blending at the surfaces, allowing controlled saturation to enhance strength and flexibility without performance loss, using specific methods of application and curing to maintain phenolic resin at the exposed surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tung oil is added to phenolic resin to increase flexibility and durability, then pressure cycle durability is improved, but dynamic friction coefficient decreases and operating temperature increases
Solution Approach 1:
The friction material is divided into distinct regions: a first region containing fiber material saturated with tung oil, and a second region containing fiber material saturated with phenolic resin. This segmentation allows each resin to perform its specialized function without negative interactions, resolving the contradiction between durability improvement and temperature control.
Solution Approach 2:
Different regions of the friction material have different resin compositions tailored to specific functional requirements. The tung oil-saturated region provides flexibility and pressure cycle durability, while the phenolic resin-saturated region maintains appropriate friction characteristics and temperature control. This local differentiation resolves the contradiction by optimizing each region for its specific purpose.
2Strength
If tung oil is added to increase flexibility, then durability in pressure cycles improves, but low speed and static friction coefficients increase and dynamic friction coefficient decreases
Solution Approach 1:
The friction material is divided into distinct regions: a first region containing fiber material saturated with tung oil, and a second region containing fiber material saturated with phenolic resin. This segmentation allows each resin to perform its specialized function without negative interactions, resolving the contradiction between flexibility improvement and friction coefficient stability.
Solution Approach 2:
Different regions of the friction material have different resin compositions tailored to specific functional requirements. The tung oil-saturated region provides flexibility and durability, while the phenolic resin-saturated region maintains appropriate friction characteristics. This local differentiation resolves the contradiction by optimizing each region for its specific purpose.
3Strength
If phenolic resin is used as glue to hold fibrous paper together, then durability increases, but material becomes brittle under aggressive conditions
Solution Approach 1:
The friction material is divided into distinct regions: a first region containing fiber material saturated with tung oil, and a second region containing fiber material saturated with phenolic resin. This segmentation allows the phenolic resin to provide strong bonding without being forced to provide flexibility, resolving the contradiction between bond strength and material stability.
Solution Approach 2:
Different regions of the friction material have different resin compositions tailored to specific functional requirements. The phenolic resin-saturated region provides strong bonding and durability, while the tung oil-saturated region provides flexibility and stability. This local differentiation resolves the contradiction by allowing each resin to excel at its specialized function.
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 friction material exhibits improved pressure cycle fatigue life and performance at higher temperatures, with reduced thickness loss and maintained integrity, as demonstrated by cyclic pressure testing, showing enhanced durability and flexibility without compromising friction characteristics.
Implementation Method 1
The tung oil is saturated within the fiber material from the first surface through a first portion of the thickness
Implementation Method 2
the phenolic resin is saturated within the fiber material from the second surface through a second portion of the thickness
Implementation Method 3
Some known friction materials delaminate under aggressive conditions, e.g., shearing of layers. Additionally, some known friction materials crack or wear away.
Data Source
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AI summary
A friction material for a clutch pad, including a fiber material and a filler material. The fiber material includes a first surface, a second surface opposite the first surface and a thickness between the first and second surfaces. The filler material includes tung oil and phenolic resin. The tung oil is saturated within the fiber material from the first surface through a first portion of the thickness, while the phenolic resin is saturated within the fiber material from the second surface through a second portion of the thickness.