Electro-Hydrostatic Pilot Circuit for Stable Aircraft Mode Switching
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Solution Overview
Problem
Existing electro-hydrostatic circuits for aircraft control surfaces face challenges in reducing power consumption and weight while preventing unintended switching of operation modes due to pressure variations in pilot hydraulic pressure.
Innovation Solution
The electro-hydrostatic circuit employs a solenoid valve in the pilot hydraulic line to control pilot hydraulic pressure, combined with a check valve and sealing material to prevent leaks, and a relief valve to manage overpressurization, allowing for a downsized solenoid valve and stable operation mode switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solenoid valve is used to switch the switching valve line, then the switching operation is reliable, but the power consumption and weight of the solenoid valve increase
Solution Approach 1:
A pilot hydraulic line is introduced as an intermediary between the solenoid valve and the switching valve. The solenoid valve controls the pilot hydraulic pressure in this intermediate line, which then acts on the switching valve to enable line switching. This mediator approach allows the solenoid valve to be smaller while maintaining reliable switching operation.
Solution Approach 2:
The invention uses hydraulic pressure in the pilot hydraulic line to control the switching valve. The solenoid valve regulates the pilot hydraulic pressure, which then energizes or de-energizes the switching valve's elastic body to achieve line switching. This hydraulic control mechanism reduces the size and power consumption requirements of the solenoid valve.
2Weight of moving object
If pilot hydraulic pressure is used to switch the switching valve line, then power consumption and weight are reduced, but unintended switching may occur due to pressure variations
Solution Approach 1:
A check valve is disposed in the pilot hydraulic line to prevent reverse flow of hydraulic fluid. This preliminary protective measure ensures that pressure variations cannot cause unintended switching by blocking the path through which pressure fluctuations might otherwise trigger erroneous valve actuation.
Solution Approach 2:
The system uses feedback control where the solenoid valve continuously adjusts the pilot hydraulic pressure based on the required switching state. The solenoid valve receives control signals and modulates the hydraulic pressure accordingly, ensuring that switching occurs only when intended and maintaining stable operation against pressure variations.
3Weight of moving object
If the solenoid valve is downsized to reduce weight and power consumption, then the circuit becomes more efficient, but the solenoid valve output force may be insufficient
Solution Approach 1:
The invention employs hydraulic amplification through the pilot hydraulic line. The downsized solenoid valve generates a small pilot hydraulic pressure that acts on a larger surface area of the switching valve's elastic body, generating sufficient force for switching. This hydraulic force multiplication allows a small solenoid to control a larger switching valve effectively.
Solution Approach 2:
The pilot hydraulic pressure acts as a counterbalancing force against the elastic body's restoring force in the switching valve. By controlling the pilot hydraulic pressure, the downsized solenoid valve can overcome the elastic body's energizing force and achieve reliable switching without requiring the solenoid itself to generate large direct force.
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 reduces the weight and power consumption of the circuit, prevents unintended switching, and protects against overpressurization, ensuring reliable operation of the aircraft's control surfaces.
Implementation Method 1
there is known an electro-hydrostatic circuit configured to switch operation modes such as a normal mode, a bypass mode, and a damping mode depending on a situation... there is known a solenoid valve that switches a line of a switching valve by using energizing force of an elastic body and electromagnetic force of a solenoid
Implementation Method 2
a check valve that is disposed in the pilot hydraulic line... by preventing the pilot hydraulic pressure from leaking out with the check valve and the sealing material
Implementation Method 3
a sealing material that is disposed in the switching valve to seal the hydraulic fluid with the pilot hydraulic pressure... by preventing the pilot hydraulic pressure from leaking out with the check valve and the sealing material
Implementation Method 4
a relief valve that is disposed in the pilot hydraulic line on a downstream side of the check valve in the circulating direction to release the pilot hydraulic pressure of the pilot hydraulic line... the relief valve suppresses overpressurization in the pilot hydraulic line
Implementation Method 5
a supply line that connects between a hydraulic supply device that supplies hydraulic fluid and a driving part to be driven by a hydraulic pressure of the hydraulic fluid
Data Source
AI summary
An electro-hydraulic circuit includes a supply line that connects between a hydraulic supply device that supplies hydraulic fluid and a driving part to be driven by a hydraulic pressure of the hydraulic fluid; a switching valve disposed in the supply line to switch between switching lines for the hydraulic fluid supplied to the driving part; a pilot hydraulic line connected to the switching valve to supply the hydraulic fluid for switching between the switching lines; a check valve disposed in the pilot hydraulic line; a solenoid valve disposed in the pilot hydraulic line to change a supply state of the hydraulic fluid to the switching valve; a sealing material disposed in the switching valve to seal the hydraulic fluid; and a relief valve disposed in the pilot hydraulic line to release the pilot hydraulic pressure