Nested Spring Bearing Cages for Compact Gas Turbine Engine Design

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Solution Overview

Problem

Gas turbine engines face challenges in accommodating multiple rolling-element bearings in confined spaces due to the space requirements of conventional spring centering cages, which are inconsistent with the need for a compact and lightweight engine design.

Innovation Solution

The use of nested, interdigitated spring bearing cages that occupy the space of a single spring bearing cage, allowing independent flexing motion and reducing the axial and radial space needed for multiple bearings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional spring centering cages are used for each bearing, then independent control over harmonic responses is achieved, but the axial and radial space required increases significantly

Engineering Contradiction:

Improveindependent control over harmonic responsesVSAvoidaxial and radial space

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent applies nesting by placing one spring cage inside another, with the inner cage (first bearing cage) positioned within the outer cage (second bearing cage). The spring arms of the inner cage are received between the spring arms of the outer cage, allowing both cages to occupy the same radial and axial space while maintaining independent functionality for controlling harmonic responses of different bearings.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent utilizes the radial dimension by arranging spring arms in an interdigitated pattern where inner cage spring arms are positioned between outer cage spring arms. This dimensional arrangement allows multiple cages to coexist in the same axial space without interfering with each other's flexing motion, effectively packing multiple bearing support functions into a single radial envelope.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If multiple spring centering cages are used for multiple bearings, then each bearing is properly supported, but the engine size and weight increase

Engineering Contradiction:

Improvebearing supportVSAvoidengine weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent merges multiple bearing support functions into a single integrated assembly where two spring cages are combined in a nested configuration. This unified structure provides support for multiple bearings while eliminating the need for separate cage assemblies, thereby reducing overall weight and simplifying the bearing support system without compromising reliability.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If multiple spring centering cages are used for multiple bearings, then each bearing is properly supported, but the device complexity increases

Engineering Contradiction:

Improvebearing supportVSAvoidassembly complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The nested configuration allows the inner bearing cage to be positioned within the outer bearing cage in a systematic manner. The spring arms are arranged in an interdigitated pattern where inner spring arms fit between outer spring arms, creating a organized and repeatable assembly structure that reduces complexity compared to separate cage installations.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 enables the mounting of multiple rolling-element bearings in a compact space, reducing the overall size and weight of the engine while maintaining independent control over harmonic responses and simplifying the assembly and logistics.

Implementation Method 1

an annular array of axially-extending first spring arms interconnecting the first bearing support ring and the mounting flange; and an annular array of axially-extending second spring arms interconnecting the second bearing support ring and the mounting flange, the second spring arms defining spaces therebetween; wherein the first spring arms are received between the second spring arms, and the bearing cages are sized so as to permit independent flexing motion of the first and second spring arms

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS10001028B2Dual spring bearing support housing

Publication Date: 2018.06.19 GENERAL ELECTRIC CO

AI summary

A bearing support housing for a gas turbine engine includes: an annular mounting flange; a first bearing cage including: an annular first bearing support ring; and an annular array of axially-extending first spring arms interconnecting the first bearing support ring and the mounting flange; and a second bearing cage including: an annular second bearing support ring; and an annular array of axially-extending second spring arms interconnecting the second bearing support ring and the mounting flange, the second spring arms defining spaces therebetween. The first spring arms are received between the second spring arms, and the bearing cages are sized so as to permit independent flexing motion of the first and second spring arms.