Aircraft Brake Actuator Shuttle Parking Lock

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Solution Overview

Problem

Existing aircraft brake actuators with parking brake members suffer from continuous electrical consumption and overheating, premature wear due to untimely friction, and efficiency loss when the coil fails, as they require permanent power to maintain the brake engaged.

Innovation Solution

An electromechanical brake actuator with a shuttle-based parking blocking member that moves between blocking and release positions using brief pulses, eliminating the need for continuous power and featuring a torque limiter and a pulse actuator to ensure the shuttle can release even if the impulse actuator fails.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the parking brake member coil remains permanently energized to maintain the brake engaged, then the brake can hold the aircraft in place, but electrical consumption increases and overheating occurs

Engineering Contradiction:
Improvebrake holding capabilityVSAvoidelectrical consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by using brief impulse signals to energize the coil only when needed to move the shuttle between positions, rather than continuous energization. The control unit sends periodic impulse signals that activate the coil temporarily to shift the shuttle, then cut power while maintaining the brake position through mechanical latching.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system implements self-service through the mechanical latching mechanism that maintains the brake engaged position without continuous electrical power. Once the shuttle is moved to the engaged position by an impulse, the mechanical structure itself maintains the position, and the system serves itself by using the brake stack friction and mechanical geometry to hold the position.

Inventive Principle:
Principle #25Self-service

2Reliability

If the parking brake member coil remains permanently energized to maintain the brake engaged, then the brake can hold the aircraft in place, but overheating occurs

Engineering Contradiction:
Improvebrake holding capabilityVSAvoidcoil temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent applies periodic action by using brief impulse signals to energize the coil only when needed to move the shuttle between positions, rather than continuous energization. The control unit sends periodic impulse signals that activate the coil temporarily to shift the shuttle, then cut power while maintaining the brake position through mechanical latching.

Inventive Principle:
Principle #19Periodic action

3Device complexity

If the park unit coil fails, then the system structure remains simple, but the park unit remains engaged causing premature wear and efficiency loss

Engineering Contradiction:
Improvesystem structureVSAvoidbrake efficiency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system implements self-service through the mechanical latching mechanism that maintains the brake engaged position without continuous electrical power. Once the shuttle is moved to the engaged position by an impulse, the mechanical structure itself maintains the position, and the system serves itself by using the brake stack friction and mechanical geometry to hold the position.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent applies inversion by designing the system so that the default state is disengaged and requires active intervention to engage, rather than the conventional approach where the default is engaged and requires active intervention to disengage. This is achieved through the forcing means that push the shuttle toward the disengaged position, reversing the conventional logic.

Inventive Principle:
Principle #13The other way round (Inversion)

4Reliability

If a conventional park unit is used, then the brake can be held engaged, but untimely friction occurs reducing actuator efficiency

Engineering Contradiction:
Improvebrake holding capabilityVSAvoidactuator efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies periodic action by using brief impulse signals to energize the coil only when needed to move the shuttle between positions, rather than continuous energization. The control unit sends periodic impulse signals that activate the coil temporarily to shift the shuttle, then cut power while maintaining the brake position through mechanical latching.

Inventive Principle:
Principle #19Periodic action

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 reduces electrical consumption, prevents overheating, and minimizes wear by allowing brief impulses to control the shuttle, ensuring the brake releases when necessary and maintaining efficiency even in case of actuator failures.

Implementation Method 1

a pulse actuator (21) causing the shuttle (17) to pass from one position to another

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

means for forcing the shuttle towards the release position when the motor of the brake actuator is energized

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP2944521B1Electromechanical brake actuator with park blocking for aircraft.
Publication Date: 2020.01.01 SAFRAN LANDING SYSTEMS
  • EP2944521B1 patent drawingFigure 1
  • EP2944521B1 patent drawingFigure 2~4

AI summary

The invention relates to an electromechanical brake actuator for aircraft wheels, comprising an electric motor (2) with a stator (3) and a rotor (4), a screw/nut assembly, one element of which is driven in rotation by the motor and the other element is constrained to slide without rotation to selectively exert a force on a stack of discs, the actuator comprising a parking locking member (10) adapted to selectively lock the motor rotor at least when the sliding element exerts a force on the stack of discs. The parking locking member comprises a shuttle (17) movable between a stable position of locking the motor rotor and a stable position of releasing it under the action of a pulse actuator (22, 24, 25) moving the shuttle from one position to the other, the brake actuator comprising means (9, 18) for forcing the shuttle towards the release position when the motor of the brake actuator is powered.