Thrust Reverser Door Position Sensing Without Shims
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Solution Overview
Problem
Existing door position sensors for thrust reverser doors in aircraft nacelles have limited detection ranges, requiring precise machining and shimming, leading to stress and maintenance challenges, and are either heavy or prone to wear.
Innovation Solution
A position sensor with a target and detector configuration where the detector is fixed relative to a target guide, allowing the target to be positioned within the detection range without shims, reducing stress and maintenance needs, and using a lightweight, flexible blade and non-magnetic guide to facilitate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a proximity sensor with limited detection range is used, then the sensor can detect the door position, but the tolerances between the door and fixed structure must be very small, requiring shims and centering devices which generate significant stresses
Solution Approach 1:
The patent introduces a guide as an intermediary element between the door and the detector. The guide receives the target and positions it within the detector's detection range, mediating the interaction and eliminating the need for precise machining and shimming between the door and fixed structure.
Solution Approach 2:
The patent replaces the mechanical shimming and centering system with a guide mechanism that actively positions the target. This substitution eliminates the need for small clearances and reduces mechanical stresses at the spigots and interfaces.
2Measurement precision
If shims and centering devices are installed to ensure proper sensor functioning, then detection accuracy is maintained, but the device complexity and manufacturing cost increase
Solution Approach 1:
The guide serves as a mediating structure that integrates the positioning function into a single component rather than requiring multiple separate elements (shims, spigots, centering devices). This reduces device complexity while maintaining detection accuracy.
Solution Approach 2:
The guide performs multiple functions: it positions the target within the detection range, protects the target, and eliminates the need for separate shimming and centering operations. This multi-functionality reduces overall device complexity.
3Measurement precision
If the target is positioned close to the detector for accurate detection, then measurement precision improves, but the target is vulnerable to damage and requires protective measures
Solution Approach 1:
The guide acts as a protective intermediary that receives and positions the target close to the detector for accurate detection while simultaneously protecting the target from damage. The guide structure shields the vulnerable target during operation.
Solution Approach 2:
The guide provides beforehand protection for the target, cushioning it from potential damages before they can occur. The target is positioned within the guide structure that prevents damage while allowing detection.
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
The sensor reduces mass and manufacturing costs, minimizes detection errors, and protects the target while ensuring precise positioning, thus simplifying assembly and reducing wear.
Implementation Method 1
The detector can be a magnetic detector emitting a magnetic field, in which case the target is adapted to change the state of this magnetic field when it is substantially opposite the detector
Data Source
Figure 1~3
Figure 4~6
AI summary
The invention relates to a position sensor (18) for an aircraft nacelle thrust reverser door for an aircraft turbojet engine, comprising: - a target (26) to be detected; - a detector (24) having a detection range and comprising a detection head (30) configured to detect the target when it enters its detection range; and - a target guide (28) configured to guide the target in order to position it in the detection range of the detector; wherein the detector is stationary relative to the target guide, and either the target is intended to be positioned on the door, and the detector and the target guide are intended to be positioned on a stationary structure of the thrust reverser, or the target is intended to be positioned on a stationary structure of the thrust reverser, and the detector and the target guide are intended to be positioned on the door.