Backup Hydraulic Pump High Pressure for Actuator Size Reduction

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Solution Overview

Problem

Aircraft actuator hydraulic systems face challenges in reducing the size of high-output actuators to fit within thinned wings while maintaining reliability and avoiding significant cost increases due to the need for high-pressure adaptations throughout the hydraulic system.

Innovation Solution

The system includes a backup hydraulic pump with a higher maximum discharge pressure than the primary pumps, allowing a single actuator to drive the control surface in case of central hydraulic power source failure, and a controller to operate the backup pump during high output conditions, enabling reduced actuator size without full system high-pressure adaptation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the aircraft central hydraulic power sources are adapted to high pressure to reduce actuator size, then the actuator size can be reduced, but the cost increases significantly due to the need for special high-pressure materials throughout the entire hydraulic system

Engineering Contradiction:
Improveactuator sizeVSAvoidsystem cost
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The patent applies local quality by providing high pressure capability only where needed - specifically in the backup hydraulic pump and the actuator - while the rest of the hydraulic system continues to operate at standard pressure. This allows the actuator to be small (using high pressure locally) without requiring expensive high-pressure materials throughout the entire hydraulic system, thus resolving the contradiction between actuator size reduction and system cost.

Inventive Principle:
Principle #3Local quality

2Reliability

If a backup hydraulic pump with higher discharge pressure is installed to enable single actuator operation during failure, then reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvecontrol surface drive reliabilityVSAvoidhydraulic system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The backup hydraulic pump is designed with multi-functionality: it serves as a backup power source during central hydraulic system failure, and simultaneously provides high pressure capability during normal operation to enable single actuator operation. This universal design reduces the need for separate dedicated components, thereby improving reliability while limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Power

If the maximum discharge pressure of the backup hydraulic pump is set higher than the primary pumps, then high output can be achieved with reduced actuator size, but the difficulty of detecting and measuring pressure increases

Engineering Contradiction:
Improveactuator outputVSAvoidpressure measurement difficulty
Core Design Contradiction:
PowerVSDifficulty of detecting and measuring

Solution Approach 1:

The backup hydraulic pump is designed with variable discharge pressure capability, dynamically adjusting its output pressure based on operational requirements. During normal operation, it provides high pressure for single actuator operation; during dual-actuator operation or when connected to the failed central system, it adjusts to match system requirements. This dynamic pressure adjustment enables high power output when needed while simplifying pressure management and measurement compared to a fixed ultra-high pressure system.

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

This configuration ensures high reliability and size reduction of actuators at a low cost, allowing them to be installed within thinned wings, while providing high output during normal and failure conditions.

Implementation Method 1

The pump of this hydraulic system is provided so as to be able to raise the pressure of the pressure oil discharged from the actuators and supply the pressure oil to the actuators

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP2457825B1Aircraft actuator hydraulic system
Publication Date: 2018.04.11 NABTESCO CORP
  • EP2457825B1 patent drawingFigure 1
  • EP2457825B1 patent drawingFigure 2
  • EP2457825B1 patent drawingFigure 3

AI summary

A first actuator (14a) drives a control surface (103a) by being operated by supply of pressure oil from a first aircraft central hydraulic power source (104) including a first aircraft central hydraulic pump (104a) . A second actuator (14b) drives the control surface by being operated by supply of pressure oil from a second aircraft central hydraulic power source (105) including a second aircraft central hydraulic pump (105a) . A backup hydraulic pump (18) is installed inside a wing (102a) of the aircraft (100) and is provided so as to be able to supply pressure oil to the first actuator (14a) when a loss or degradation in a function of at least one of the first aircraft central hydraulic power source (104) and the second aircraft central hydraulic power source (105) occurs. A maximum discharge pressure of the backup hydraulic pump (18) is set to be greater than maximum discharge pressures of the first aircraft central hydraulic pump (104a) and the second aircraft central hydraulic pump (104b).