Epicyclic Reduction Gear Layout for Satellite-Driven Accessories

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Solution Overview

Problem

Conventional planetary gear reducers in turbomachines are not compatible with all architectures, particularly when the turbine shaft is guided relative to the fan shaft upstream of the reduction gear, limiting the arrangement of accessory equipment and increasing the size of the nacelle.

Innovation Solution

A mobile sun gear and satellite configuration with a stationary planet carrier, where the rotor of the equipment is driven by the satellite, allowing for the attachment of accessory equipment and reducing the size of the AGB box, and enabling the rotation of multiple equipment pieces to increase electrical or hydraulic power without increasing the nacelle size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the equipment is driven by the sun gear upstream of the reducer, then the equipment can be moved into the enclosure and the AGB box size is reduced, but this arrangement is not compatible with turbomachine architectures that include guiding the turbine shaft relative to the fan shaft upstream of the reduction gear

Engineering Contradiction:
Improvecompatibility with turbomachine architecturesVSAvoidarrangement complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of driving equipment from the sun gear upstream of the reducer, the invention inverts the arrangement by driving equipment from the satellite downstream of the reducer. This reversal of the drive location resolves the conflict with turbine shaft guiding architectures while maintaining the benefit of compact equipment integration.

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

Solution Approach 2:

The satellite is designed to serve dual functions: it participates in the planetary gear reduction mechanism and simultaneously drives accessory equipment. This multi-functionality allows the same component to serve both reduction and equipment drive purposes, enhancing adaptability across different turbomachine architectures without requiring separate drive systems.

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

2Volume of stationary object

If multiple pieces of equipment are attached to the AGB box, then the AGB box size increases and consequently the nacelle dimensions increase, but attaching equipment to the reducer allows limiting the AGB box size

Engineering Contradiction:
Improvenacelle volumeVSAvoidequipment arrangement flexibility
Core Design Contradiction:
Volume of stationary objectVSAdaptability or versatility

Solution Approach 1:

The invention merges the equipment drive function with the planetary gear reducer by attaching equipment to the satellite carrier or satellite components. This consolidation eliminates the need for a separate AGB box for equipment mounting, reducing overall nacelle volume while maintaining equipment arrangement flexibility through the compact integrated design.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If equipment is driven by the satellite of the reducer, then the arrangement is compatible with more turbomachine architectures, but the satellite must be designed to handle both reduction and equipment drive functions

Engineering Contradiction:
Improvearchitecture compatibilityVSAvoidsatellite design complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The satellite is designed as a universal component that performs both the planetary gear reduction function and the equipment drive function. By integrating these two functions into a single component, the design achieves broad architecture compatibility while the added complexity is confined to the satellite's dual functionality rather than requiring separate systems.

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

Data Source

PatentEP3999729B1Epicyclic reduction gear for a turbomachine
Publication Date: 2023.05.10 SAFRAN TRANSMISSION SYST
  • EP3999729B1 patent drawingFigure 1
  • EP3999729B1 patent drawingFigure 2
  • EP3999729B1 patent drawingFigure 3

AI summary

The invention relates to an epicyclic reduction gear (15) for a turbomachine, comprising: - a sun wheel (16) that is rotatable about a first axis (A); - a ring gear (17) surrounding the sun wheel (16) and being rotatable about the first axis (A); - at least one planetary gear (18) that is rotatable about a second axis (B), the planetary gear (18) being meshed with the sun wheel (16) and the ring gear (17); - an immobile planet carrier (19), the planetary gear (18) being rotatably guided about the second axis (B) with respect to a bearing (29) of the planet carrier (19); - an item of equipment (21) comprising a rotor (22). The invention is characterized in that the item of equipment (21) is fastened to the bearing (29) of the planet carrier (19) and the rotor (22) of the item of equipment (21) is rotatably driven by the planetary gear (18).