Bearing Centering Spring-Damper for Balanced Radial Vibration

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Solution Overview

Problem

Turbomachine bearing centering spring/damper systems face challenges in effectively accommodating radial vibration and inertial loading due to aircraft maneuvering, with existing configurations either requiring excessive fluid supply or having different damping characteristics, and lacking optimal compliance and sealing efficiency.

Innovation Solution

A gas turbine engine design featuring a radial spring and two damper rings with damping chambers, where the radial spring is axially compressed between the damper rings, and fluid communication channels between the chambers provide balanced damping, with seals ensuring efficient fluid retention and compliance through a high open area fraction in the cross-sectional design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a closed damper configuration with two grooves and seals is used, then sealing efficiency is improved, but fluid supply requirements increase

Engineering Contradiction:
Improvesealing efficiencyVSAvoidfluid supply requirements
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent divides the damping system into two separate damping chambers (first damping chamber and second damping chamber) with independent seals, allowing each chamber to be sealed independently. This segmentation enables efficient sealing while reducing overall fluid requirements compared to a single large closed chamber

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different sealing approaches to different locations: the first seal is positioned at the first axial side of the radial spring, and the second seal is positioned at the second axial side. This local differentiation allows optimized sealing efficiency at each location while minimizing fluid retention requirements

Inventive Principle:
Principle #3Local quality

2Reliability

If existing damper configurations are used, then damping function is provided, but compliance and sealing efficiency are not optimized

Engineering Contradiction:
Improvesealing efficiencyVSAvoidcompliance optimization
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a radial spring that is axially compressed between two damper rings, creating a dynamic compliance mechanism. The spring allows radial movement while maintaining axial positioning, optimizing compliance without compromising sealing efficiency. The spring rate can be adjusted to match specific application requirements

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent nests the radial spring within the damping chambers formed by the two damper rings. The spring is positioned between the rings and surrounded by the damping chambers, creating a compact nested structure that optimizes both compliance and sealing efficiency within a confined space

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

The design effectively accommodates radial vibration and maintains efficient damping, reducing fluid requirements and enhancing compliance, while ensuring reliable sealing and balanced damping characteristics, thereby improving the overall performance of turbomachine bearings.

Implementation Method 1

A radial spring extends radially between the ring and the first member

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

A first damping chamber is radially between an outer diameter surface portion of the first damper ring and an inner diameter surface portion of the first member

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP3690267B1Bearing centering spring and damper
Publication Date: 2021.11.17 RTX CORP
  • EP3690267B1 patent drawingFigure 1
  • EP3690267B1 patent drawingFigure 1A
  • EP3690267B1 patent drawingFigure 1B

AI summary

A machine has first (120) and second (40) members. A bearing (52) has an inner race (54) mounted to the second member and an outer race (56) rotatable relative to the inner race about an axis. A ring (110) holds the outer race. A radial spring (102) extends radially between the ring and the first member. First (104A) and second (104B) damper rings extending radially between the ring and the first member at first and second axial sides of the radial spring. First (150A) and second (150B) damping chambers are radially between an outer diameter surface portion of the respective damper rings and an inner diameter surface portion of the first member.