Sealed Turbofan Enclosure for Modular Disassembly

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Solution Overview

Problem

Current reduction gear systems in turbomachines are incompatible with modular engine designs, requiring disassembly that breaks the seal of the front enclosure, leading to oil drainage and contamination risks during maintenance.

Innovation Solution

A turbofan engine design with a lubrication enclosure that forms a coaxial ring with the turbine shaft, using drive means integrated into the movable sealing walls to allow uncoupling of the LP shaft without breaking the seal, and featuring a drive ring that participates in the sealing, enabling the reduction device to remain sealed during disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the LP shaft is disconnected for modular disassembly, then the engine can be decomposed into separate modules, but the seal of the front enclosure is broken and oil leaks

Engineering Contradiction:
ImprovemodularityVSAvoidsealing
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The front enclosure is segmented into a fixed part and a movable part that can be independently displaced. The movable part is coupled to the LP shaft and can be separated from the fixed part, allowing the LP shaft to be disconnected while the movable part remains in position to maintain the seal. This segmentation enables modular disassembly without compromising the sealing integrity of the front enclosure.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the LP shaft is removed, then maintenance access is improved, but oil drainage and contamination occur

Engineering Contradiction:
Improvemaintenance accessVSAvoidoil contamination
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The movable part of the front enclosure is pre-configured to remain in position and maintain sealing when the LP shaft is removed. By preparing the enclosure structure in advance with a movable part that can be independently positioned, the system prevents oil drainage and contamination before maintenance operations begin, eliminating the need for oil drainage procedures.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If the reduction gear is driven directly by the LP shaft, then the drive connection is simple, but the seal is compromised during shaft removal

Engineering Contradiction:
Improvedrive connectionVSAvoidsealing
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The drive connection is segmented by coupling the movable part of the front enclosure to the LP shaft, allowing the reduction gear to remain driven while the LP shaft can be independently removed. This segmentation separates the drive function from the shaft, enabling shaft removal without compromising the seal or the drive connection to the reduction gear.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3071802B1Front enclosure which is sealed during the modular dismantling of a turbojet with reduction gear
Publication Date: 2020.01.01 SAFRAN AIRCRAFT ENGINES SAS
  • EP3071802B1 patent drawingFigure 1
  • EP3071802B1 patent drawingFigure 2
  • EP3071802B1 patent drawingFigure 3~5

AI summary

The invention relates to a turbofan engine comprising a fan (S) driven, via a fan shaft (3) supported by at least two first bearings (11, 12), by a turbine shaft (4) supported by at least one second bearing (10) comprising a stationary ring (25) and a movable ring (26), said turbine shaft driving said fan shaft (3) through a device for reducing the speed of rotation (7), said device for reducing the speed of rotation and said first and second bearings being housed in a lubrication enclosure (E1) in which the shell comprises stationary portions and movable portions connected to one another by sealing means (29, 30, 31), said reducing device comprising an inducer (27) shaped so as to receive the torque transmitted by said turbine shaft via driving means (8, 9) connected to said movable ring, characterised in that the lubrication enclosure forms a coaxial ring with the turbine shaft and said driving means (8, 9) comprise a girth gear which is part of the movable sealing walls of the shell of the lubrication enclosure (E1).