Gear Assembly Support Torque Reacting Flex Portions

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Solution Overview

Problem

Current gear assembly supports in gas turbine engines face challenges in balancing cost, weight, and torque transfer efficiency, as they aim to reduce weight and cost while maintaining optimal functional requirements.

Innovation Solution

The proposed gear assembly support includes a spline engagement with the engine case, a flex portion with a torque reacting portion, and radially extending flanges to provide a balanced interference fit and torque transmission, allowing for independent adjustments to optimize moment loading and reduce material thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the flexible support configuration is optimized for torque transfer, then torque transmission efficiency is improved, but weight and cost increase

Engineering Contradiction:
Improvetorque transfer efficiencyVSAvoidsupport structure weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The flexible support is divided into three distinct portions: a first portion for interference fit with the case, a second portion for interference fit with the gear assembly, and a torque reacting portion with flex portions connecting them. This segmentation allows each portion to be optimized for its specific function, enabling weight reduction in non-critical areas while maintaining torque transfer efficiency in critical paths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the flexible support have different structural characteristics tailored to their specific functions. The first and second portions have interference fit configurations for secure mounting, while the torque reacting portion has flex portions with specific thicknesses and geometries optimized for torque transmission. This local optimization allows the support to achieve high torque transfer efficiency without requiring excessive material throughout the entire structure.

Inventive Principle:
Principle #3Local quality

2Reliability

If the flexible support configuration is optimized for torque transfer, then torque transmission efficiency is improved, but manufacturing cost increases

Engineering Contradiction:
Improvetorque transfer efficiencyVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By segmenting the flexible support into distinct functional portions, each can be manufactured using optimized processes for its specific requirements. The interference fit portions can be precision-machined, while the flex portions can be formed using cost-effective methods such as forging or additive manufacturing, reducing overall manufacturing cost while maintaining torque transfer efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention allows for adjustment of geometric parameters such as the thickness of the torque reacting portion, the dimensions of the flex portions, and the interference fit tolerances. These parameters can be optimized to balance manufacturing cost with torque transfer efficiency, enabling cost-effective production while achieving the required performance level.

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If material thickness is reduced to decrease weight, then weight is reduced, but structural integrity and torque transfer capability deteriorate

Engineering Contradiction:
Improvesupport structure weightVSAvoidstructural integrity
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The flexible support features locally optimized thickness distributions: the torque reacting portion has sufficient thickness to maintain structural integrity and torque transfer capability, while other portions can be thinner to reduce weight. The flex portions have specific thicknesses tailored to their bending and torque transmission requirements, ensuring structural adequacy only where needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention may utilize composite material constructions or hybrid material approaches in the flexible support, combining materials with different properties to achieve high strength-to-weight ratio. This allows reduced overall material thickness while maintaining the structural integrity and torque transfer capability required for reliable operation.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3019726B1Gear assembly support for a gas turbine engine, corresponding turbofan engine and method of supporting a gear assembly within a gas turbine engine
Publication Date: 2020.09.02 RTX CORP
  • EP3019726B1 patent drawingFigure 1
  • EP3019726B1 patent drawingFigure 2
  • EP3019726B1 patent drawingFigure 3

AI summary

A gear assembly support for a gas turbine engine includes a first portion engageable to a case of the gas turbine engine and a second portion configured for supporting a gear assembly. The support includes a torque reacting portion for transferring torque from the second portion to the first portion, a forward flange disposed forward of the torque reacting portion, the forward flange defining a first interface to the case and an aft flange disposed aft of the torque reacting portion, the aft flange defining a second interface to the case.