Segmented Friction Plate with Tapered Grooves for Clutch Cooling

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Solution Overview

Problem

Wet clutches in limited slip differential systems experience low cooling efficiency due to passive splash cooling methods, where it is difficult for sufficient oil to reach the clutch interface, leading to thermal degradation and reduced reliability.

Innovation Solution

A friction plate design with segmented friction material and tapered grooves that act as fluid paths to enhance oil flow and cooling, featuring a core plate with ears and a friction lining made of high-strength fibers and resin, optimized for alternating arrangement with separator plates to maximize cooling efficiency and load capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If passive splash cooling is used, then device complexity is reduced, but cooling efficiency deteriorates

Engineering Contradiction:
Improvecooling system complexityVSAvoidclutch interface temperature
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The friction material is divided into multiple segments with grooves between them, creating channels for oil flow. This segmentation allows passive splash cooling to be more effective by providing dedicated pathways for cooling oil to reach the friction interface, resolving the contradiction between simple cooling system design and adequate cooling efficiency.

Inventive Principle:
Principle #1Segmentation

2Temperature

If forced cooling with oil channels is used, then cooling efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveclutch interface temperatureVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The grooves in the friction material segments serve dual purposes: they maintain the friction material structure and simultaneously function as self-contained cooling channels. The design eliminates the need for separate forced cooling systems with pumps and complex fluid channels, as the friction material itself provides the cooling pathways through its segmented structure.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If friction material is made as single piece, then manufacturing is simplified, but cooling efficiency deteriorates

Engineering Contradiction:
Improvefriction material manufacturingVSAvoidclutch interface temperature
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The friction material is manufactured as multiple segments with grooves between them, creating inherent channels for oil flow. While this segmentation adds manufacturing steps compared to a single-piece design, it enables effective passive cooling by allowing oil to flow through the grooves to the friction interface, thereby resolving the contradiction between manufacturing simplicity and cooling efficiency.

Inventive Principle:
Principle #1Segmentation

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 design improves cooling efficiency by directing oil flow through the grooves, reducing thermal degradation and maintaining clutch reliability under high sliding speeds and pressures, while maintaining sufficient load capacity and traction.

Implementation Method 1

A plurality of grooves are disposed between said plurality of friction segments, wherein each segment has tapered sides so that the grooves have a first width adjacent the first outer diameter and a second width, which is smaller than the first width, adjacent the inner diameter

Methodology Applied
Scientific EffectFluid flow through grooves:

Data Source

PatentEP2791526B1Segmented friction material for clutches
Publication Date: 2019.12.11 EATON CORP
  • EP2791526B1 patent drawingFigure 1
  • EP2791526B1 patent drawingFigure 2A~2C
  • EP2791526B1 patent drawingFigure 3~4

AI summary

A friction plate for a clutch assembly includes a core plate and a plurality of friction segments made of a friction material. A plurality of grooves are disposed between said plurality of friction segments. Each segment has tapered sides so that the grooves have a first width adjacent the outer diameter of the core plate and a smaller second width smaller adjacent the inner diameter of the core plate. This tapered groove structure directs oil from the outside the clutch assembly to the inside to improve cooling efficiency.