Aircraft Landing Gear Sensor Integrated into Push Rod

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Solution Overview

Problem

Existing sensor devices for determining the state of aircraft landing gear legs face issues with measurement tolerances and are prone to damage and contamination due to external signal generators being exposed to harsh conditions, leading to inaccurate readings.

Innovation Solution

A sensor device with a signal transmitter integrated into the push rod of the landing gear leg, protected by a notch or semicircular grooves, and a signal sensor positioned between shock absorber seals, reduces exposure to damage and contamination, providing more precise measurements by directly measuring the push rod's stroke without secondary parts' tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external signal generators are used on steering arms or auxiliary struts, then the sensor device can determine landing gear leg state, but the signal generators are exposed to damage, icing, and contamination

Engineering Contradiction:
Improvesensor device reliabilityVSAvoiddamage and contamination to signal generators
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The signal generator is extracted from the external steering arms or auxiliary struts and relocated to be integrated directly into the push rod structure. This extraction removes the signal generator from the harmful external environment while maintaining its functional integration in the landing gear system.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The signal generator is merged with the push rod by integrating it into the push rod's basic material or coating. This combining protects the signal generator within the push rod structure, shielding it from damage, icing, and contamination while maintaining its signal transmission function.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If measurements are taken from secondary parts like steering arms or auxiliary struts, then the landing gear leg state can be inferred, but measurement tolerances increase due to tolerances in secondary parts

Engineering Contradiction:
Improvelanding gear leg state measurementVSAvoidtolerances of steering arms or auxiliary struts
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The measurement function is extracted from secondary parts (steering arms, auxiliary struts) and relocated to the push rod itself. This eliminates the tolerance chain introduced by secondary parts, as the signal generator now directly measures the push rod's position without intermediate components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of measuring secondary parts and inferring push rod position, the measurement is inverted to directly monitor the push rod's position through an integrated signal generator. This reversal of the measurement approach eliminates the need for tolerance-based inference.

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

3Object-affected harmful factors

If signal transmitter is integrated into the push rod, then protection against damage and contamination is improved, but additional manufacturing steps are required

Engineering Contradiction:
Improveprotection of signal transmitterVSAvoidsignal transmitter integration
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The signal transmitter is merged with the push rod's basic material or coating, creating a unified structure. This integration protects the signal transmitter within the push rod while utilizing existing manufacturing processes for the push rod, minimizing additional manufacturing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The push rod serves multiple functions: structural support and signal transmission. By making the signal transmitter integral to the push rod, the same component performs both mechanical and sensing functions, reducing the need for separate protected housings or additional manufacturing steps.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design enhances measurement accuracy and reliability by protecting the signal transmitter and sensor from damage and contamination, reducing the tolerance chain and ensuring precise monitoring of the landing gear leg's condition, critical for aircraft safety.

Implementation Method 1

it is common to use inductive proximity sensors

Methodology Applied
Scientific EffectInductive proximity sensing: Electromagnetic Induction

Data Source

PatentEP2818405B1Sensor
Publication Date: 2018.09.05 LIEBHERR AEROSPACE LINDENBERG GMBH
  • EP2818405B1 patent drawingFigure 1a~1c
  • EP2818405B1 patent drawingFigure 2a~2c

AI summary

The present invention relates to a sensor device (1) for determining the state of a landing gear leg of a landing gear of an aircraft, in particular of an airplane, comprising at least one push rod (3), at least one shock absorber housing (2) in which the push rod is movably received, at least one signal transmitter (4) and at least one signal sensor (5), wherein the signal transmitter is arranged on or in the push rod.