Dual Torque Path Coupling for Jam-Tolerant Hybrid Drives

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Solution Overview

Problem

Existing mechanical connection devices in hybrid motor installations, such as those in aircraft, face challenges with internal blocking of electric machines and the risk of fire due to short-circuits, which can lead to mechanical device blocking and safety hazards.

Innovation Solution

A bidirectional mechanical connection device with a free wheel and a claot link, where the free wheel transmits engine torque during the engine mode and the claot link transmits generator torque during the electric generator mode, along with a fuse section to dissociate the electric machine from the mechanical device in case of blocking or short-circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical connection device is used to connect the electric machine to the mechanical device, then the electric machine can be disconnected in case of internal jamming, but the risk of fire due to short-circuits remains and mechanical device blocking can still occur

Engineering Contradiction:
Improveprotection against internal jammingVSAvoidfire risk and mechanical blocking
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The mechanical connection device is segmented into two independent torque transmission paths: a first path for motor mode and a second path for generator mode. This segmentation allows each path to be independently protected against failures, so that a jamming or short-circuit in one path does not necessarily block the entire mechanical device.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A fuse section is introduced as an intermediary element in the first torque transmission path. This fuse section acts as a sacrificial component that breaks under excessive load or short-circuit conditions, isolating the electric machine from the mechanical device and preventing fire hazards while allowing the mechanical device to continue operating through the second torque transmission path.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If a single torque transmission path is used, then the device structure is simpler, but the mechanical device can be blocked if the electric machine jams

Engineering Contradiction:
Improveconnection device structureVSAvoidresistance to mechanical blocking
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The torque transmission path is divided into two separate paths with distinct mechanical connections. The first path includes a first shaft and fuse section, while the second path includes a second shaft. This segmentation ensures that a jamming in the electric machine affects only one path, allowing the mechanical device to continue operating through the other path.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fuse section is designed as a predetermined weak point that will fail before the electric machine or mechanical device suffers catastrophic damage. This beforehand cushioning protects the system by sacrificing a relatively simple component (the fuse section) to prevent more serious failures.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If the electric machine is directly connected to the mechanical device, then the connection is more straightforward, but short-circuits can cause fire hazards and mechanical blocking

Engineering Contradiction:
Improveconnection implementationVSAvoidfire hazard from short-circuits
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The fuse section serves as an intermediary protective element between the electric machine and the mechanical device. In the event of a short-circuit, the fuse section breaks the electrical and mechanical connection, preventing fire hazards while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The connection is segmented into two independent paths, allowing the system to maintain ease of manufacture while incorporating safety features. Each path can be manufactured separately and then assembled, reducing complexity despite the added safety mechanisms.

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

This solution effectively prevents mechanical device blocking by allowing the free wheel to desynchronize and potentially break the fuse section in case of electric machine blocking, while ensuring safe operation during electric generator mode by isolating the mechanical device from potential short-circuits.

Implementation Method 1

a free wheel (35) to only transmit a motor torque from the first shaft (25) to the second shaft (30) during the motor mode

Methodology Applied
Scientific EffectFree wheel mechanism: Ratchet

Implementation Method 2

The connecting device (20) has a fusible section (45) to separate the electric machine (9) from the mechanical device (4) in the event of this first shaft (25) becoming blocked

Methodology Applied
Scientific EffectFusible section failure: Fracture Mechanics

Data Source

PatentEP4530490A1System having a mechanical connection device with two mechanical torque transmission paths
Publication Date: 2025.04.02 EUROCOPTER FRANCE SA
  • EP4530490A1 patent drawingFigure 1
  • EP4530490A1 patent drawingFigure 2~3
  • EP4530490A1 patent drawingFigure 4~5

AI summary

The present invention relates to a system comprising a linkage device (20) having a first shaft (25) and a second shaft (30), the linkage device (20) comprising a freewheel (35) interposed between the first shaft (25) and the second shaft (30) capable of transmitting only motor torque from the first shaft (25) to the second shaft (30) in motor mode. The linkage device (20) comprises a coupler (40), the coupler (40) being provided with a fusible section (45), the linkage device (20) comprising a dog clutch (50) capable of transmitting only motor torque from the coupler (40) to the first shaft (25) in electric generator mode.