Aircraft Actuator Thermal Management via Mechanical Locking

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Solution Overview

Problem

Current thermal management methods for electromechanical actuators in aerospace applications, such as heat sink natural convective cooling, result in larger and heavier components, making them challenging to install in thin wing envelopes and inefficient in terms of weight and size, particularly due to the need for significant heat dissipation.

Innovation Solution

A system that utilizes a mechanical locking device, such as an anti-extension device, to lock the actuator in place when it is not moving, reducing the need for continuous motor power and heat dissipation, by engaging the actuator mechanically when it is in a steady state position, thereby minimizing heat generation in the motor and power drive electronics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heat sink natural convective cooling is used for thermal management, then heat dissipation is achieved, but the size and weight of the actuator increase

Engineering Contradiction:

Improveheat dissipationVSAvoidactuator weight

Core Design Contradiction:

TemperatureVSWeight of stationary object

Solution Approach 1:

The patent applies dynamic thermal management by switching between active cooling (motor running) and passive locking (motor stopped) modes based on operational requirements. The locking device is engaged only when the actuator is stationary, creating a dynamic system that adapts its thermal management strategy to real-time operational states, thereby reducing the need for continuously sized heat sinks.

Inventive Principle:

Principle #15Dynamics

2Temperature

If heat sink natural convective cooling is used for thermal management, then heat dissipation is achieved, but the actuator size increases

Engineering Contradiction:

Improveheat dissipationVSAvoidactuator volume

Core Design Contradiction:

TemperatureVSVolume of moving object

Solution Approach 1:

The system dynamically transitions between active motor mode requiring cooling and passive locking mode with minimal heat generation. This dynamic operation allows for smaller heat sinks compared to continuous operation systems, as cooling is only required during brief motor-active periods rather than continuously.

Inventive Principle:

Principle #15Dynamics

3Stability of the object's composition

If continuous motor power is applied to hold position, then position stability is maintained, but heat generation increases

Engineering Contradiction:

Improveposition stabilityVSAvoidheat generation

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The patent extracts the heat generation problem by separating the position-holding function from the motor. The mechanical locking device takes over the position-holding task entirely, removing the motor from the equation during stationary periods. This extraction eliminates Joule heating from the system while maintaining position stability through pure mechanical means.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the electrical-mechanical system (motor applying continuous torque) with a purely mechanical system (locking device with physical constraint). This substitution eliminates the need for continuous electrical power and associated heat generation, using mechanical interlocking instead of electromagnetic force to maintain position.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach significantly reduces the size and weight of the heat sinks, lowers power consumption, and decreases the internal temperature of the motor and electronics, enhancing aircraft efficiency and reliability by reducing thermal stress on electronic components.

Implementation Method 1

A system for controlling an electromechanical actuator of an aircraft comprises a locking device configured to mechanically lock the actuator in a first fixed position

Methodology Applied

Scientific EffectMechanical locking: Mechanical Fastener

Implementation Method 2

the controller is configured to monitor a position of the actuator during flight and to detect when the actuator has not moved for a set amount of time

Methodology Applied

Scientific EffectPosition monitoring:

Implementation Method 3

The current methods for the thermal management of EMAs for such aerospace applications are based on heat sink natural convective cooling in ambient air

Methodology Applied

Scientific EffectNatural convection cooling: Free Convection

Implementation Method 4

Due to the Joule effect, however, this current being drawn generates heat that must then be dissipated outside the motor and its power drive electronics

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11319058B2EMA thermal management optimization

Publication Date: 2022.05.03 GOODRICH ACTUATION SYST

AI summary

A system for controlling an electromechanical actuator of an aircraft includes a locking device configured to mechanically lock said actuator in a first fixed position and to mechanically unlock said actuator from said first fixed position and a controller configured to be in bi-directional communication with both said locking device and said actuator. The controller is configured to monitor a position of said actuator during flight and to detect when said actuator has not moved for a set amount of time, said controller further being configured to instruct said locking device to lock said actuator in said first, locked position when said set time has been reached. In addition, there is provided a method for controlling the thermal properties of an electromechanical actuator of an aircraft.