Floating-Ring Lead-Lag Damper for Shaft Misalignment Stability

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Solution Overview

Problem

Existing shock absorbers or dampers in automotive and aerospace industries are prone to failure due to varying and repeated forces, and there is a need for improved performance in managing center shaft misalignment and fluid exchange to enhance stability and reduce wear.

Innovation Solution

A lead-lag damper with floating annular rings and a secondary spring mechanism that includes guide structures to control fluid exchange and maintain coaxial alignment, using materials like polymeric, rubber, or ceramic to prevent galvanic corrosion, and elastomer bearings for dynamic sealing and volume compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional shock absorbers or dampers are used in automotive and aerospace industries, then basic shock absorption function is provided, but they are prone to failure due to varying and repeated forces

Engineering Contradiction:
ImprovedurabilityVSAvoidresistance to varying and repeated forces
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent employs a floating annular ring that can dynamically adjust its position axially within the damper body. This dynamic element allows the damper to adapt to varying and repeated forces by modifying the fluid exchange gap, thereby improving reliability without compromising strength under dynamic loading conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of fluid exchange gap between chambers by allowing the floating annular ring to move axially. This parameter change enables the damper to respond to varying forces, improving its durability and resistance to repeated stress cycles

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If existing dampers are used, then shock absorption is provided, but center shaft misalignment causes instability and increased wear

Engineering Contradiction:
ImprovestabilityVSAvoidwear resistance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The floating annular ring acts as an intermediary element between the center shaft and the fluid chambers. It compensates for misalignment by adjusting its axial position, thereby maintaining stable fluid exchange and reducing wear on the center shaft while preserving overall system stability

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conventional damper designs are used, then basic damping function is achieved, but fluid exchange consistency deteriorates under misalignment conditions

Engineering Contradiction:
Improvefluid exchange consistencyVSAvoidcoaxial alignment
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The floating annular ring provides dynamic compensation for coaxial alignment deviations. By moving axially in response to misalignment, it maintains a consistent fluid exchange gap, ensuring reliable fluid exchange even when the center shaft is not perfectly aligned

Inventive Principle:
Principle #15Dynamics

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 lead-lag damper provides stable performance by tracking center shaft misalignment, reducing wear, and maintaining consistent fluid exchange, thus enhancing the durability and efficiency of shock absorption.

Implementation Method 1

control a consistent fluid exchange gap, respectively, between the second and third fluid chambers and the third and fourth fluid chambers of the outer tube

Methodology Applied
Scientific EffectFluid exchange:

Implementation Method 2

one or more substantially annular elastomer bearings inside the outer tube

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

the guide structure configured to limit movement of the floating annular ring to a predefined axial position and allow the floating annular ring to translate radially along with the spacer tube in operation

Methodology Applied
Scientific EffectMechanical constraint:

Implementation Method 4

a plunger-spring system inside the inner tube to provide volume compensation fluid exchange between one or both of the second and third fluid chambers and the first fluid chamber

Methodology Applied
Scientific EffectSpring mechanism: Spring

Data Source

PatentEP3917832B1Lead-LAG damper
Publication Date: 2026.04.22 ITT MANUFACTURING ENTERPRISES LLC
  • EP3917832B1 patent drawingFigure 1
  • EP3917832B1 patent drawingFigure 2
  • EP3917832B1 patent drawingFigure 3

AI summary

Technologies are generally described for lead-lag dampers. An example lead-lag may include a single- or two-stage floating annular ring, elastomer bearings, a tension stop, a compression stop, and a plunger/spring volume compensator. The floating annular ring(s) form orifice(s) in conjunction with the remaining damper components may provide stable performance by tracking with any center shaft misalignment during operation. The lead-lag damper may also include a secondary spring system allowing or disallowing fluid flow between chambers based on slow or sudden movement of the shaft.