Aircraft Servo Control Sealing via Controlled Leakage

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Aircraft hydraulic systems with servo controls face limitations due to dynamic seal leaks, leading to high maintenance costs and reduced performance, as the heating from friction degrades seals and causes unintended leaks, making it difficult to detect dormant failures and maintain the systems effectively.

Innovation Solution

The implementation of a controlled leak servo control system, which features a main sealing means allowing predetermined leaks and is housed in a closed enclosure, eliminating the need for dynamic seals and containing any hydraulic fluid leakage, thereby optimizing maintenance and reducing wear on components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dynamic seals are used in servo controls to prevent fluid leakage, then sealing performance is improved, but the seals deteriorate due to friction heating and cause unintended leaks over time

Engineering Contradiction:
Improvesealing performanceVSAvoidservice life of seals
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent removes dynamic seals from the servo control system entirely. Instead of using seals that contact and friction against moving parts, the invention employs static sealing solutions where the hydraulic fluid is contained through the system architecture and controlled leakage paths, eliminating the root cause of seal deterioration.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent accepts that some fluid leakage is inevitable and converts this potential harm into a beneficial feature by directing the leakage into a closed enclosure. The leaked fluid lubricates other moving parts within the enclosure and is then recovered and reused, transforming a reliability problem into a maintenance benefit.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If dynamic seals are used to contain hydraulic fluid, then fluid containment is improved, but maintenance costs increase due to seal wear and replacement

Engineering Contradiction:
Improvefluid containmentVSAvoidmaintenance cost
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent implements a fluid recovery system where hydraulic fluid that leaks from the servo control is collected in a closed enclosure, filtered, and reused. This eliminates the need for frequent fluid replacement and reduces maintenance costs associated with seal failures.

Inventive Principle:
Principle #34Discarding and recovering

3Reliability

If dynamic seals are installed between moving parts, then sealing effectiveness is improved, but system complexity increases due to seal installation and maintenance

Engineering Contradiction:
Improvesealing effectivenessVSAvoidseal installation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent eliminates dynamic seals from the system, removing the complexity associated with their installation, alignment, and replacement. The servo control assembly becomes simpler without these components, and the closed enclosure design provides sealing through its structure rather than through multiple dynamic seal interfaces.

Inventive Principle:
Principle #2Taking out (Extraction)

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 enhances the reliability and safety of aircraft systems by reducing the risk of unplanned leaks, improving dynamic performance, and allowing for the reuse of hydraulic fluid, thus lowering maintenance costs and extending the lifespan of components.

Implementation Method 1

a main sealing means with controlled leakage allowing a hydraulic fluid to leak outside of said body

Methodology Applied
Scientific EffectControlled leakage:

Implementation Method 2

each body of said servo control being arranged in said enclosure so that said fluid is collected in said enclosure

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Implementation Method 3

the use of the servo-control induces the heating of the dynamic seals by friction

Methodology Applied
Scientific EffectFriction heating: Friction

Data Source

PatentEP2933186B1Hydraulic aircraft system including at least one servo, associated rotor and aircraft
Publication Date: 2016.07.06 EUROCOPTER FRANCE SA
  • EP2933186B1 patent drawingFigure 1~2
  • EP2933186B1 patent drawingFigure 3~5
  • EP2933186B1 patent drawingFigure 6~7

AI summary

A hydraulic system of an aircraft, the system comprising at least one servo-control, each servo-control comprising at least one cylinder together with a drive rod and a piston arranged in each cylinder. Between each cylinder of servo-control and the drive rod of that servo-control, at least one servo-control presents main sealing means with controlled leakage allowing a hydraulic fluid to leak out from the cylinder, the hydraulic system further comprising at least one enclosure, each cylinder of the servo-control being arranged inside the enclosure so that the fluid is collected in the enclosure.