Rolling Bearing Wear Monitoring via Differential Strain Waveforms

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Solution Overview

Problem

Current bearing monitoring apparatuses are unable to detect the wear state of rolling bearings effectively.

Innovation Solution

A bearing monitoring apparatus that includes a strain gauge with two resistors arranged in the same direction as the rolling elements, generating distorted waveforms and a differential waveform to detect wear by comparing it against a reference value.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a vibration sensor is used to monitor bearing operation states, then the bearing defect peak can be detected, but the wear state of the rolling bearing cannot be detected

Engineering Contradiction:
Improvedetection capabilityVSAvoidwear state detection
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces the conventional vibration sensor (mechanical detection system) with a strain gauge-based electrical measurement system. The strain gauge detects strain on the bearing ring, which is then converted into electrical signals for analysis. This substitution enables the detection of wear states that are not detectable by conventional vibration sensors, while maintaining the ability to detect bearing defect peaks.

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

Solution Approach 2:

The patent changes the detection parameter from vibration amplitude/frequency to strain magnitude and its rate of change. By measuring strain on the bearing ring and analyzing its temporal characteristics, the system can detect both bearing defects and wear states. The strain parameter provides more comprehensive information about the bearing condition, enabling wear detection in addition to defect detection.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If strain gauge with resistors arranged in the same direction as rolling elements is used, then wear state detection is enabled, but device complexity increases

Engineering Contradiction:
Improvewear state detectionVSAvoidstrain gauge configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The strain gauge is divided into multiple resistive elements (first resistor and second resistor) arranged at different positions along the bearing ring. Each resistor detects strain at its specific location, and by comparing the strain signals from different positions, the system can detect wear states. This segmentation approach enables wear detection while keeping each individual resistor simple in structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a signal processing unit that acts as an intermediary between the strain gauge and the analysis system. This intermediary processes the raw strain signals from the resistors, extracting relevant features such as strain magnitude and rate of change. By placing this intermediary processing layer, the complex task of wear detection is simplified into manageable signal processing steps, reducing the overall system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 accurate detection of wear states in rolling bearings, enhancing monitoring capabilities and preventing premature failure.

Implementation Method 1

a strain gauge configured to detect strain of the outer ring or the inner ring, the strain gauge including at least two resistors

Methodology Applied
Scientific EffectStrain detection: Piezoresistive Effect

Data Source

PatentEP3971430B1Bearing monitoring device and bearing monitoring method
Publication Date: 2023.01.11 MINEBEAMITSUMI INC
  • EP3971430B1 patent drawingFigure 1
  • EP3971430B1 patent drawingFigure 2(a)~2(c)
  • EP3971430B1 patent drawingFigure 3

AI summary

A bearing monitoring apparatus includes a rolling bearing. The rolling bearing includes an outer ring and an inner ring disposed coaxially with the outer ring, the inner ring being on an inner peripheral side of the outer ring. The rolling bearing includes multiple rolling elements disposed between the outer ring and the inner ring. The rolling bearing includes a strain gauge configured to detect strain of the outer ring or the inner ring, the strain gauge including at least two resistors, and the resistors being arranged in a same direction as an arrangement direction of the rolling elements so as to correspond to spacing between rolling elements that are next to each other. The bearing monitoring apparatus includes a waveform generator configured to generate a first distorted waveform based on an output of one resistor and to generate a second distorted waveform based on an output of another resistor. The bearing monitoring apparatus includes a subtracting unit configured to subtract the second distorted waveform from the first distorted waveform to generate a differential waveform. The bearing monitoring apparatus includes a comparator configured to compare the differential waveform against a reference value to detect a wear state of the rolling bearing.