Tandem Thrust Bearing Preload for Gas Turbine Stability

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Solution Overview

Problem

Existing high speed rolling element bearing systems for gas turbine engines face challenges in handling varying and intermittent thrust loads, particularly when the thrust load reverses or is no longer acting, leading to instability and reduced bearing life, as tandem mounted bearings can only carry thrust in one direction and require additional bearings to manage axial loads, increasing weight, cost, and reliability concerns.

Innovation Solution

A preload generating device is introduced to apply an axial preload thrust load between tandem mounted thrust bearings, allowing continued operation during thrust load reversal without additional bearings, using a spring-based preload generator that adjusts the distance between bearing rings to load one bearing against the other upon removal of primary thrust, ensuring equal load sharing and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tandem mounted bearings are used to carry thrust load in one direction, then the bearing system can handle primary thrust load effectively, but the system becomes unstable and bearing life reduces when thrust load reverses or is removed

Engineering Contradiction:
Improvebearing lifeVSAvoidoperational stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The preload generator applies a preliminary axial thrust preload to the tandem mounted bearings before the primary thrust load is applied or reversed. This preliminary action ensures that the bearings remain loaded and stable throughout the entire operating cycle, preventing instability when the primary thrust load is removed or reverses direction, thereby extending bearing life and maintaining operational stability

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If additional bearings are added to manage axial loads in both directions, then the bearing system can handle thrust load reversal, but the weight, cost, and device complexity increase

Engineering Contradiction:
Improvethrust load handling capabilityVSAvoidbearing system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of adding additional bearings to handle thrust load reversal, the invention uses a preload generator to apply a preliminary axial preload that maintains bearing stability throughout the entire operating cycle. This approach achieves adaptability to thrust load reversal without increasing device complexity, as the preload generator can be integrated into the existing bearing arrangement

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The preload generator enables the existing tandem mounted bearings to serve dual purposes: handling primary thrust load in one direction and maintaining stability during thrust load reversal or removal. The bearings essentially serve themselves by remaining loaded through the preload mechanism, eliminating the need for additional dedicated bearings for reverse thrust handling

Inventive Principle:
Principle #25Self-service

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

The preload generator ensures operational stability and increased bearing life by maintaining load sharing between bearings during thrust load changes, eliminating the need for additional bearings and reducing weight and cost, while maintaining efficient load distribution across the bearing system.

Implementation Method 1

using a spring-based preload generator that adjusts the distance between bearing rings to load one bearing against the other upon removal of primary thrust

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2519727B1Gas turbine engine and high speed rolling element bearing system
Publication Date: 2020.02.05 ROLLS ROYCE CORP
  • EP2519727B1 patent drawingFigure 1~2
  • EP2519727B1 patent drawingFigure 3~4

AI summary

One embodiment of the present invention is a unique gas turbine engine. Another embodiment is a unique gas turbine engine high speed rolling element bearing system. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and high speed rolling element bearing systems for gas turbine engines. Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall become apparent from the description and figures provided herewith.