Dual Clutch Coolant Channel Layout for Compact Torque Distribution

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Solution Overview

Problem

Existing double clutch units face challenges in absorbing high forces with minimal installation space and wear, while also maintaining continuous operation with slip, especially in high-temperature conditions where friction disc clutches are exposed and require effective cooling and lubrication.

Innovation Solution

The double clutch unit incorporates a unique coolant distribution system where the first distribution channel supplies coolant to the first disk pack and partially forwards it to the second distribution channel, creating a series connection to ensure efficient cooling and lubrication, with features like axial projections, through-holes, and annular gaps to accommodate speed differences and centrifugal forces, and uses a deflection ring and Archimedean screws for enhanced coolant flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If friction disc clutches are used in dual clutch units, then torque transmission capability is improved, but high temperatures and wear occur during operation

Engineering Contradiction:
Improvetorque transmission capabilityVSAvoidoperating temperature
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent employs a hydraulic cooling system where coolant is pumped through distribution channels in the inner disk carriers and through-holes to cool the friction discs. The coolant flow is controlled by a deflection ring that directs fluid to different channels based on operational conditions, effectively managing heat dissipation during high-power operation.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the physical state and flow parameters of the coolant to optimize cooling efficiency. The coolant flow rate, pressure, and distribution are dynamically adjusted based on operational conditions, with the deflection ring redirecting flow between series-connected channels to match thermal loads during different driving phases.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple disk packs are used for variable torque distribution, then torque control flexibility is improved, but installation space requirement increases

Engineering Contradiction:
Improvetorque distribution flexibilityVSAvoidinstallation space
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent implements a nested configuration where the first and second disk packs are arranged concentrically around a common rotational axis. The inner disk carriers rotate within the outer disk carrier, allowing multiple clutch assemblies to occupy overlapping radial and axial spaces, thereby reducing the overall installation volume while maintaining independent torque control capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a linear arrangement of clutch packs to a three-dimensional concentric configuration. By utilizing radial and axial dimensions simultaneously, the design accommodates multiple disk packs in a compact volume, with coolant distribution channels extending through multiple dimensions to reach all friction surfaces efficiently.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If through-bores are used to connect distribution channels, then coolant flow efficiency is improved, but speed differences between rotating components cause flow disruption

Engineering Contradiction:
Improvecoolant flow efficiencyVSAvoidcoolant flow continuity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent employs dynamic sealing elements within the through-bores that adapt to speed differences between the inner and outer disk carriers. The sealing mechanism maintains fluid connection during relative rotation, allowing the through-holes to remain open and functional across a range of operational speeds without disrupting coolant flow continuity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces an intermediary sealing mechanism in the through-bores that mediates between the rotating inner disk carrier and the stationary or differently-speed outer disk carrier. This intermediary element maintains fluid communication despite differential rotation, ensuring continuous coolant supply to both disk packs.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If series connection of distribution channels is used, then cooling coverage is improved, but pressure loss increases

Engineering Contradiction:
Improvecooling coverageVSAvoidcoolant pressure loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality optimization by varying the cross-sectional area, length, and orientation of coolant channels in different regions of the dual clutch unit. High-flow channels are provided where heat generation is greatest, while pressure loss is minimized in regions with lower thermal loads. The deflection ring creates locally optimized flow paths that balance cooling coverage with pressure conservation.

Inventive Principle:
Principle #3Local quality

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 allows for compact, high-force absorption with reduced wear and continuous operation, ensuring uniform cooling and lubrication of both disk packs, even under varying operational conditions, and enables variable torque distribution to output shafts without the need for a differential gear, improving driving dynamics and stability.

Implementation Method 1

the borehole longitudinal axis of the at least one through-bore encloses a bore angle with the rotation axis

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

uses a deflection ring and Archimedean screws for enhanced coolant flow

Methodology Applied
Scientific EffectArchimedean screw principle: Archimedes Screw

Data Source

PatentEP3794244B1Dual clutch unit and drive assembly comprising such a dual clutch unit
Publication Date: 2024.11.27 GKN AUTOMOTIVE LTD
  • EP3794244B1 patent drawingFigure 1~2
  • EP3794244B1 patent drawingFigure 3~4
  • EP3794244B1 patent drawingFigure 5~7

AI summary

The present invention relates to a dual clutch unit for variable torque distribution over two output shafts, comprising: an outer disc carrier (2) rotatably driveable about a rotation axis (X); a first inner disc carrier (3); a first disk pack (7) for transmitting torque from the outer disc carrier (2) to the first inner disc carrier (3); a second inner disc carrier (4), the first inner disc carrier (3) and the second inner disc carrier (4) being arranged rotatably relative to one another about the rotation axis (X); a second disk pack (8) for transmitting torque from the outer disc carrier (2) to the second inner disc carrier (4); a central oil feed (27) for supplying coolant to the first disk pack (7) and the second disk pack (8); a first distributor channel (41), which is formed in the first inner disc carrier (3) and has an inlet opening (43), via which the first distributor channel (41) is fluidically connected to the central oil feed (27); a second distributor channel (52), which is formed in the second inner disc carrier (4) and is fluidically connected to the central oil feed (27) via the first distributor channel (41); and outlet channels (25), which are formed in the first inner disc carrier (3) for conducting the coolant and/or lubricant into the first disk pack (7) and in the second inner disc carrier (4) for conducting the coolant into the second disk pack (8). The present invention also relates to a drive assembly comprising such a dual clutch unit.