Vibration Isolator with Compliant Base and Dense Fluid

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Solution Overview

Problem

Current vibration isolation systems in aircraft, particularly rotary wing aircraft, face challenges in minimizing size, weight, and conserving engineering resources while effectively isolating harmonic vibrations from propulsion systems, with existing solutions often relying on toxic fluids and requiring radical redesigns.

Innovation Solution

The development of a vibration isolation system utilizing a non-corrosive, high-density, low-viscosity fluid within a piston arrangement with conical flow diverters and elastomeric seals, combined with a compliant base using elastic members, to decelerate fluid flow and reduce vibration transfer, thereby enhancing the system's performance without significant redesign.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dense, low-viscosity fluid is used as the tuning mass to counterbalance oscillating forces, then vibration isolation performance is improved, but the system becomes more sensitive to fluid leakage and contamination

Engineering Contradiction:
Improvevibration isolation performanceVSAvoidfluid leakage and contamination
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the toxic, corrosive mercury fluid with a less critical fluid that can be more easily replaced if contaminated or leaked. This allows the system to use dense, low-viscosity fluid for optimal vibration isolation performance while accepting that the fluid may need periodic replacement rather than requiring indefinite service life.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent introduces seals and containment mechanisms as intermediary elements between the fluid and the external environment. These intermediaries protect the system from fluid leakage and contamination while maintaining the beneficial vibration isolation properties of the dense fluid.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Weight of moving object

If the length, weight, and overall size of the isolation device are minimized, then aircraft payload capacity is improved, but vibration isolation effectiveness may be reduced

Engineering Contradiction:
Improveisolation device weightVSAvoidvibration isolation effectiveness
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent uses a hydraulic system with a dense fluid in a confined chamber to provide vibration isolation. By utilizing the high density of the fluid, the system achieves effective vibration counterbalancing in a compact volume, minimizing the size and weight of the isolation device while maintaining effectiveness.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the physical parameters of the isolation system by using a dense, low-viscosity fluid with specific gravitational properties. This allows the system to achieve effective vibration isolation with minimal mass and volume, as the dense fluid provides strong inertial forces in a compact package.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If incremental improvements are made to existing vibration isolation systems, then engineering resources are conserved, but significant performance breakthroughs may be limited

Engineering Contradiction:
Improveengineering resource conservationVSAvoidperformance breakthrough potential
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies existing vibration isolation system parameters by changing the fluid properties (density and viscosity) and the chamber geometry. These parameter changes provide performance improvements while maintaining compatibility with existing system architectures, requiring only incremental rather than radical redesign.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent essentially creates a modified version of the Halwes isolator design, copying the fundamental concept but improving it by replacing mercury with a less toxic fluid and optimizing the chamber and piston design. This allows incremental improvement without complete redesign.

Inventive Principle:
Principle #26Copying

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 provides a compact, efficient, and reliable vibration isolation system that effectively reduces harmonic vibrations in aircraft, improving performance while avoiding the use of toxic fluids and minimizing weight and size constraints, thus enabling incremental improvements without radical re-engineering.

Implementation Method 1

the inertial characteristics of a dense, low-viscosity fluid, combined with a hydraulic advantage resulting from a piston arrangement, could harness the out-of-phase acceleration to generate counterbalancing forces to attenuate or cancel vibration

Methodology Applied
Scientific EffectInertial characteristics: Inertia

Implementation Method 2

the inertial characteristics of a dense, low-viscosity fluid, combined with a hydraulic advantage resulting from a piston arrangement, could harness the out-of-phase acceleration to generate counterbalancing forces

Methodology Applied
Scientific EffectHydraulic advantage: Hydraulic Press

Implementation Method 3

a piston arrangement with conical flow diverters and elastomeric seals, combined with a compliant base using elastic members, to decelerate fluid flow and reduce vibration transfer

Methodology Applied
Scientific EffectFlow deceleration: Drag

Implementation Method 4

elastomeric seals, combined with a compliant base using elastic members, to decelerate fluid flow and reduce vibration transfer

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2191189B1Method and apparatus for improved vibration isolation
Publication Date: 2015.11.11 BELL HELICOPTER TEXTRON INC
  • EP2191189B1 patent drawingFigure 1~2A
  • EP2191189B1 patent drawingFigure 2B~3
  • EP2191189B1 patent drawingFigure 4A~4B

AI summary

A vibration isolator is disclosed having a housing which defines a fluid chamber. A piston, which is movable to and from a down position, is disposed within the housing. A vibration isolation fluid is disposed within the fluid chamber. A passage having a predetermined diameter extends through the piston to permit the vibration isolation fluid to flow from one fluid chamber to the other. An elastic element is provided for reducing transmission of vibrations from the piston to the housing when the piston is at the down position.