Helicopter Drive Train Redundant Mount for Housing Rupture

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Solution Overview

Problem

The existing drive train systems for helicopters face challenges in maintaining engine integrity during rupture of the front housing of the reduction gear, leading to increased mass and cost due to over-dimensioned, massive steel components for mechanical strength.

Innovation Solution

A redundant mount is introduced around the output shaft, between the main gearbox and the front housing, creating a secondary load-absorbing path that redirects loads through rolling bearings in case of front housing rupture, thereby maintaining engine integration with the helicopter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a massive steel flange is used to improve mechanical strength and retain the engine integral with the helicopter during front housing rupture, then the reliability and strength are improved, but the weight and cost of the component increase significantly

Engineering Contradiction:

Improveengine retention during front housing ruptureVSAvoidmass of the flange

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent introduces a redundant mount system with energy-absorbing elements (such as deformable connectors or sacrificial structural features) that are pre-configured to activate during front housing rupture. These elements absorb impact energy and prevent engine detachment without requiring an overly massive flange, thus providing the necessary reliability while controlling weight.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent changes the material or structural parameters of the flange by integrating a redundant mount system with energy-absorbing capabilities. This allows the flange to achieve higher effective strength during rupture events without proportionally increasing its mass, as the redundant mount provides additional load-bearing capacity only when needed.

Inventive Principle:

Principle #35Parameter changes

2Strength

If the flange is over-dimensioned to ensure mechanical strength, then the strength and reliability are improved, but the manufacturing cost increases

Engineering Contradiction:

Improvemechanical strength of the flangeVSAvoidmanufacturing cost of the flange

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent segments the engine mounting system into two functional parts: a standard flange for normal operation and a redundant mount system for emergency retention. This segmentation allows the standard flange to be manufactured at normal dimensions and cost, while the redundant mount (separate component or integrated feature) provides additional strength only when needed, reducing overall manufacturing cost compared to an entirely over-dimensioned flange.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the structural parameters of the mounting system by adding a redundant mount with energy-absorbing elements. This allows the primary flange to maintain standard manufacturing specifications and cost, while the redundant mount provides enhanced strength capabilities during rupture events without requiring the entire assembly to be over-dimensioned.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a redundant mount with secondary load-absorbing path is introduced, then the reliability during front housing rupture is improved, but the device complexity increases

Engineering Contradiction:

Improveengine retention during ruptureVSAvoidcomplexity of the mount structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the redundant mount system with the existing flange structure, integrating energy-absorbing elements directly into the mounting assembly rather than adding completely separate components. This merging approach provides the necessary reliability during rupture while minimizing the increase in device complexity by combining multiple functions into a unified structure.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The redundant mount system is designed to serve multiple functions: it provides structural support during normal operation and activates as a secondary load-absorbing path during front housing rupture. This multi-functionality reduces the need for entirely separate emergency retention systems, thereby limiting the increase in device complexity while improving reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10875634B2Drive train

Publication Date: 2020.12.29 SAFRAN TRANSMISSION SYST

AI summary

A drive train for a helicopter, which includes an engine, a reduction gear and a main gearbox, the reduction gear including an output shaft, which are received in assembled front and rear housings, the output shaft being supported and guided rotatably by a plurality of rolling bearings, mounted in the housings. The drive train includes a redundant mount arranged around the output shaft and between a wall of the main gearbox and the front end of the front housing, and the redundant mount is configured, sized and attached to the wall of the main gearbox and to the front end of the front housing so as to create, if the front housing breaks, a secondary path for absorbing loads passing via the redundant mount, via the output shaft of the reduction gear and via the bearings.