Magnetic Permeability Zones for Propeller Blade Angle Feedback

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Solution Overview

Problem

Existing propeller blade angle feedback systems in featherable aircraft propeller systems suffer from reduced signal quality and complex, costly manufacturing processes, making accurate blade pitch measurement challenging, especially in reverse and low pitch situations.

Innovation Solution

A blade angle feedback assembly featuring magnetically permeable position markers embedded in a feedback device, with sensors configured to detect these markers, providing improved signal quality and reduced manufacturing complexity through a C-shaped cross-section and diamond-shaped magnetic poles, and protective bumpers for durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional feedback devices with raised markers are used, then blade angle measurement is possible, but signal quality is reduced and manufacturing is complex and costly

Engineering Contradiction:
Improveblade angle measurement accuracyVSAvoidmanufacturing complexity and cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The feedback device is segmented into distinct magnetically permeable markers embedded in non-magnetically permeable material, creating discrete detectable features that simplify both manufacturing and signal detection while maintaining measurement precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mechanical raised markers are replaced with magnetically permeable markers detected by magnetic sensors, eliminating the need for complex mechanical structures and reducing manufacturing complexity while improving signal quality

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If complex feedback device structures are used, then measurement accuracy is maintained, but manufacturing cost increases

Engineering Contradiction:
Improveblade pitch measurement accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The invention changes the material parameters of the feedback device by using magnetically permeable markers embedded in non-magnetically permeable material, allowing for simpler manufacturing processes while maintaining the magnetic field interaction necessary for accurate measurement

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The feedback device uses composite construction with magnetically permeable markers embedded in non-magnetically permeable material, combining the advantages of both materials to achieve accurate measurement with simplified manufacturing

Inventive Principle:
Principle #40Composite materials

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 solution enhances signal clarity and precision in measuring propeller blade angle and rotational velocity, reducing manufacturing costs while maintaining accuracy and durability, even in harsh operating conditions.

Implementation Method 1

The sensor has a C-shaped cross section and includes opposite polarities or magnetic poles at opposite ends of the C-shape

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

The feedback device includes a plurality of magnetically permeable position markers embedded therein

Methodology Applied
Scientific EffectMagnetic permeability: Ferromagnetism

Data Source

PatentEP3744630B1Feedback device with differing magnetic permeability zones
Publication Date: 2023.08.02 PRATT & WHITNEY CANADA CORP
  • EP3744630B1 patent drawingFigure 1
  • EP3744630B1 patent drawingFigure 2
  • EP3744630B1 patent drawingFigure 3A~3B

AI summary

A blade angle feedback assembly (200) for an aircraft-bladed rotor (130) is provided. The rotor is rotatable about a longitudinal axis (A) and having an adjustable blade pitch angle. The assembly comprises a feedback device (204) coupled to rotate with the rotor (130) with adjustment of the blade pitch angle, the feedback device (204) comprising a non-magnetically permeable body defining a root surface (304) and a plurality of magnetically permeable position markers (208) circumferentially disposed on the root surface (304), and at least one sensor (206) mounted adjacent the feedback device (204) and configured to detect a passage of the plurality of position markers (208) as the feedback device (204) rotates about the longitudinal axis (A).