Double Concentric Clutch Oil Distribution in Tight Axial Space

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Solution Overview

Problem

In sports car transaxles with limited axial packaging space, ensuring effective oil distribution through double clutches is challenging, especially when stationary, and current designs face issues with assembly complexity and cost, while maintaining performance and reliability.

Innovation Solution

A double clutch unit design with concentrically arranged clutch packs and an oil distributor between them, where the oil distributor ensures centrifugal oil distribution even when the vehicle is stationary, and the use of spline connections and seals for easier assembly and maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a multi-plate clutch with forced oil lubrication is used to cool the clutch, then thermal management is improved, but oil distribution is lost when the vehicle is stationary

Engineering Contradiction:
Improveclutch thermal managementVSAvoidoil distribution reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent introduces a stationary oil distribution mechanism that operates independently of clutch rotation. The oil distributor is connected to the housing and uses stationary channels to deliver oil to the clutch packs, ensuring reliable lubrication and cooling whether the clutch is rotating or stationary.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces a stationary oil distributor as an intermediary component between the oil supply and the clutch packs. This distributor uses stationary channels and openings to mediate oil flow, ensuring reliable delivery to the clutch friction plates and separator plates regardless of clutch rotation state.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of stationary object

If two concentric clutches are used to fit within limited axial space, then packaging space is reduced, but assembly complexity increases

Engineering Contradiction:
Improveaxial packaging spaceVSAvoidassembly complexity
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent combines the oil distribution function with the clutch structure by integrating the oil distributor into the housing and making it common to both inner and outer clutch packs. This shared oil distribution system reduces the number of separate components and simplifies assembly compared to having separate oil distribution systems for each clutch.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The stationary oil distributor serves multiple functions: it distributes oil to both the inner and outer clutch packs, provides structural support, and maintains proper spacing between components. This multi-functionality reduces the overall number of parts needed in the assembly.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If the inner clutch pack input side is rotated relative to the outer clutch pack input side, then oil distribution is improved during rotation, but the clutch structure becomes more complex

Engineering Contradiction:
Improveoil distributionVSAvoidclutch structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of rotating the oil distribution mechanism with the clutch (as in conventional designs), the patent inverts the approach by making the oil distributor stationary and fixed to the housing. This stationary configuration simplifies the structure while maintaining effective oil distribution through properly positioned channels and openings.

Inventive Principle:
Principle #13The other way round (Inversion)

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

This design reduces packaging space, improves oil distribution, simplifies assembly, and maintains performance and reliability by ensuring consistent lubrication and torque transfer across gear changes, while allowing for easier maintenance and repair.

Implementation Method 1

Oil distribution into and through the clutches plates relies in part on centrifugal forces

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3969771B1Power flow in a double concentric clutch
Publication Date: 2024.02.14 TRANSMISIONES Y EQUIPOS MECANICOS S A DE
  • EP3969771B1 patent drawingFigure 1
  • EP3969771B1 patent drawingFigure 2
  • EP3969771B1 patent drawingFigure 3

AI summary

The present invention relates to a double concentric clutch for a transmission comprising a power flow to both clutches that extends around an outer drive drum, and for an inner via an oil distributor. Parts are assembled using splines, and axial movements are limited using retaining rings which increases ease of assembly and disassembly.