Friction Layer Surface Texture for Water-Based Lubrication

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Solution Overview

Problem

Current wet-running multi-plate clutches and brakes rely heavily on oil-based lubricants, which are environmentally incompatible, dependent on the petroleum industry, and have exhausted their potential, while water-based lubricants have shown promise but require further development to improve synchronization and transfer case performance.

Innovation Solution

A friction assembly using a friction element with a highly structured surface and a water-based lubricant and coolant mixture, incorporating solid lubricant particles, which reduces power losses and increases frictional torque, and maintains consistent friction performance despite temperature, pressure, and speed fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If water-based lubricant is used instead of oil-based lubricant, then environmental compatibility is improved, but friction performance and power losses are worsened

Engineering Contradiction:
Improveenvironmental compatibilityVSAvoidpower losses
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The invention changes the chemical composition parameters of the lubricant from oil-based to water-based (glycol-water mixture), and adjusts the solid lubricant particle size parameters (5-50 μm) to optimize friction performance while maintaining environmental compatibility and reducing power losses

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite lubrication system combining water-based glycol lubricant with suspended solid lubricant particles (graphite, MoS2, or PTFE), forming a hybrid lubricant that achieves both environmental compatibility and effective friction reduction

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If water-based lubricant is used instead of oil-based lubricant, then environmental compatibility is improved, but frictional torque is worsened

Engineering Contradiction:
Improveenvironmental compatibilityVSAvoidfrictional torque
Core Design Contradiction:
Object-affected harmful factorsVSForce

Solution Approach 1:

The invention creates a composite lubrication system combining water-based glycol lubricant with suspended solid lubricant particles (graphite, MoS2, or PTFE), forming a hybrid lubricant that achieves both environmental compatibility and effective friction reduction

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the chemical composition parameters of the lubricant from oil-based to water-based (glycol-water mixture), and adjusts the solid lubricant particle size parameters (5-50 μm) to optimize friction performance while maintaining environmental compatibility and reducing power losses

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If friction layer has highly structured surface, then solid lubricant particles can be embedded reducing static friction, but contact area with counter-friction surface is reduced

Engineering Contradiction:
Improvestatic frictionVSAvoidcontact area
Core Design Contradiction:
Loss of energyVSArea of stationary object

Solution Approach 1:

The invention applies local quality by creating a highly structured surface with varying topography where solid lubricant particles are embedded in peaks and valleys, providing localized lubrication zones that reduce static friction while maintaining sufficient contact area for torque transmission

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The highly structured surface creates a porous-like topology that can embed and retain solid lubricant particles, allowing the friction layer to store and release lubricant during operation, reducing static friction without significantly reducing contact area

Inventive Principle:
Principle #31Porous materials

4Loss of energy

If solid lubricant particles are embedded in friction layer surface, then static friction is reduced, but manufacturing complexity increases

Engineering Contradiction:
Improvestatic frictionVSAvoidsurface structure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The invention applies preliminary action by pre-embedding solid lubricant particles into the friction layer surface during manufacturing, so that the lubricant is already in position before operation begins, eliminating the need for complex external lubrication systems and simplifying the overall device structure

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention merges the friction layer structure with solid lubricant particles into a single integrated component, combining the structural function of the friction layer with the lubrication function of embedded particles, thereby reducing the number of separate components and simplifying manufacturing

Inventive Principle:
Principle #5Merging (Combining)

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 achieves reduced power losses, increased frictional torque, and extended service life by incorporating solid lubricant particles into the friction layer, ensuring a stable coefficient of friction and minimizing the contact surface area, thus improving engine efficiency and reducing environmental impact.

Implementation Method 1

a water-based lubricant and coolant mixture, in which solid lubricant particles are suspended

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

water-based lubricant and coolant mixture

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 3

reducing static friction due to the adhesive effect of the water on the friction layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2670999B1Friction material
Publication Date: 2019.05.08 MIBA FRICTEC
  • EP2670999B1 patent drawingFigure 1~3

AI summary

The invention relates to a friction element (1), comprising a main body (2) having a friction layer (5), characterised in that the friction layer (5) has an arithmetic average roughness value Ra according to DIN EN ISO 4287 of at least 3 μm, a wave depth Wt according to DIN EN ISO 4287 of at least 30 μm and a mean groove width Rsm according to DIN EN ISO 4287 of at least 150 μm.