Magnetic Coding for Ceramic Hybrid Bearing Defect Detection

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Solution Overview

Problem

Existing methods cannot continuously monitor ceramic hybrid bearings installed in aircraft engines for defects in ceramic rolling elements and bearing shells during operation without falsifying measurement values.

Innovation Solution

The outer ferromagnetic bearing shell is magnetically coded, and inverse magnetostriction is used to generate a pressure profile measurement, allowing for continuous detection of defects by comparing the pressure signature with known profiles of damaged and undamaged bearings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If vibration sensors are used to monitor ceramic hybrid bearings during operation, then continuous monitoring is enabled, but measurement values are falsified due to damping and frequency distortion through the rigid strut

Engineering Contradiction:
Improvecontinuity of monitoringVSAvoidaccuracy of vibration measurements
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical vibration measurement system with a magnetic field-based measurement system. Instead of using vibration sensors connected through rigid struts that dampen and distort signals, the invention uses magnetically coded bearing shells that generate magnetic field signals. These magnetic field changes are detected by magnetic sensors, providing continuous monitoring without the mechanical transmission path that causes measurement falsification.

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

2Measurement precision

If inverse magnetostriction method is used to detect defects in bearing shells, then defect detection capability is improved, but the bearing shell must be made of ferromagnetic material which limits material selection

Engineering Contradiction:
Improvedefect detection capabilityVSAvoidmaterial selection flexibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by magnetically coding only specific areas of the bearing shell rather than requiring the entire bearing shell to be ferromagnetic. The bearing shell can have ferromagnetic regions with magnetic codes embedded in them, while other parts can remain non-ferromagnetic. This allows defect detection through inverse magnetostriction in the coded regions while maintaining material selection flexibility for the overall bearing structure.

Inventive Principle:
Principle #3Local quality

3Reliability

If magnetic coding is applied to the bearing shell for inverse magnetostriction testing, then defect detection reliability is increased, but device complexity increases due to additional magnetic coding and sensing components

Engineering Contradiction:
Improvedefect detection reliabilityVSAvoidcomplexity of magnetic coding and sensing system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses magnetic coding as a form of information copying. Magnetic codes are embedded in the bearing shell that replicate specific magnetic field patterns. When defects occur, changes in these magnetic field patterns are detected by magnetic sensors. This copying approach allows reliable defect detection through magnetic field changes without requiring complex mechanical or electrical sensing systems, simplifying the overall device while maintaining high reliability.

Inventive Principle:
Principle #26Copying

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

Enables continuous, non-contact monitoring of ceramic rolling elements and bearing shells during operation, effectively identifying potential defects and reducing interference from external magnetic fields.

Implementation Method 1

the pressure profile that the ceramic rolling element in the form of balls, rollers, etc. exerts on the bearing surfaces of the bearing shells is measured over part of the circumference of the bearing shell or the entire circumference of the bearing shell using the inverse magnetostriction method

Methodology Applied
Scientific EffectInverse magnetostriction: Magnetostriction

Data Source

PatentEP2381235B1Method and device for recognising defects in the bearing surfaces of bearing shells and the roller bodies of ceramic-hybrid bearings
Publication Date: 2020.01.15 ROLLS ROYCE DEUT LTD & CO KG
  • EP2381235B1 patent drawingFigure 1
  • EP2381235B1 patent drawingFigure 2
  • EP2381235B1 patent drawingFigure 3

AI summary

The method involves magnetically coding outer or inner ferromagnetic bearing shells i.e. outer- and inner races (11, 12), of a ceramic-hybrid bearing (10). The magnetic coding of the bearing shells is utilized as a generator for testing of bearing surfaces of the bearing shells and a ceramic roller body i.e. ceramic ball (13), using inverse magnetostriction. The entire bearing surfaces and/or complete periphery of the shells are magnetically coded. Magnetic fields i.e. magnetic structures (15), are formed in the shells, run against each other and are spatially separated from each other. An independent claim is also included for a device for detecting errors in bearing surfaces of bearing shells and in roller bodies of ceramic-hybrid bearings.