Electromechanical Actuator Axial Displacement Detection
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Solution Overview
Problem
Existing electromechanical actuators for aircraft brake systems face challenges in reliably detecting applied braking force without incurring high costs or environmental sensitivity issues, particularly with methods like current monitoring and force sensors.
Innovation Solution
The electromechanical actuator detects axial displacement of a nut to determine if a braking force is applied, using a cost-effective solution that minimizes accidental detection, employing a compression spring and contactors to detect axial displacement and determine the presence of a braking force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If current monitoring is used to detect braking force application, then detection capability is provided, but the risk of untimely detection increases
Solution Approach 1:
The patent replaces electrical current monitoring with a mechanical detection system based on axial displacement measurement of the nut. The detection device measures the actual axial displacement of the nut along the pushing direction, which directly correlates to braking force application. This mechanical substitution eliminates the indirect and unreliable current-based detection method while providing direct, accurate measurement of the braking state.
Solution Approach 2:
The patent introduces an intermediary detection mechanism (the detection device measuring nut displacement) that serves as a reliable mediator between the actuator's mechanical action and the control system. This intermediary provides accurate feedback about actual braking force application, allowing the control system to make informed decisions without relying on indirect current measurements that may lead to untimely detection.
2Measurement precision
If a force sensor is integrated directly into the actuator, then accurate braking force detection is achieved, but costs and environmental sensitivity increase
Solution Approach 1:
The patent extracts the detection function from complex force sensing elements and implements it through a simplified mechanism that measures axial displacement of the nut. Instead of integrating expensive and environmentally sensitive force sensors directly into the actuator, the solution extracts the essential information (axial movement) that correlates to braking force, providing accurate detection through a more robust and cost-effective means.
Solution Approach 2:
The patent employs a detection device based on axial displacement measurement that is simpler, more durable, and less environmentally sensitive than integrated force sensors. This approach uses readily available displacement sensing technology rather than expensive force sensing elements, reducing both cost and environmental sensitivity while maintaining accurate detection capability.
3Reliability
If axial displacement of the nut is detected, then reliable and low-cost braking force detection is achieved
Solution Approach 1:
The patent leverages the existing nut component in the actuator mechanism, which already serves the function of converting rotational motor motion to linear pushing motion. By adding detection capability to this existing universal component, the system achieves reliable braking force detection without adding separate complex detection mechanisms. The nut serves both its original mechanical function and as the basis for displacement measurement.
Solution Approach 2:
The detection device utilizes the nut's own axial displacement as the measurement parameter, allowing the existing mechanical component to provide information about braking force application. The system essentially uses the nut's own movement to detect the braking state, eliminating the need for separate sensing elements and reducing overall system complexity while maintaining high reliability.
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 provides a reliable and inexpensive method to detect braking force application, reducing the risk of untimely detection and ensuring accurate monitoring of the actuator's behavior, thus enhancing safety and efficiency in aircraft braking systems.
Implementation Method 1
employing a compression spring and contactors to detect axial displacement
Implementation Method 2
employing a compression spring and contactors to detect axial displacement
Data Source
Figure 1
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Figure 4~6d
AI summary
The invention relates to an electromechanical actuator for a vehicle brake comprising a body (4) in which are arranged an electric motor (5) and a threaded plunger cooperating via a helical linkage with a nut (8) driven in rotation by the electric motor (5). According to the invention, the nut (8) is axially movable within the body (4) of the actuator between a rest position towards which the nut (8) is repelled by elastic means, and an active position towards which the nut is displaced against the elastic means when a braking force is applied, the actuator further comprising means for detecting the axial displacement of the nut.