Rolling Bearing Thermal Monitoring for Early Damage Detection

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Solution Overview

Problem

Existing methods for detecting damage in large rolling bearings, such as those used in wind turbines, are unreliable, complex, or expensive, particularly due to high frictional torques and uneven load distribution, making it difficult to detect early damage through torque, vibration, or temperature monitoring.

Innovation Solution

A system using multiple temperature sensors positioned strategically around the rolling bearing to measure load, idle, and ambient temperatures, combined with an evaluation device to compare these readings against reference values, allowing for early detection of damage by analyzing temperature differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If torque measurement is used for damage detection in large rolling bearings, then damage can be detected, but the high frictional torques make the measurement difficult and reduce measurement precision

Engineering Contradiction:
Improvedamage detection precisionVSAvoidtorque measurement design complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical torque measurement with thermal field measurement. Instead of measuring mechanical torque directly (which is complicated by high frictional torques), the system measures temperature distribution around the bearing. Damage causes localized friction increases that generate detectable temperature variations, allowing indirect detection of bearing conditions through thermal fields rather than mechanical measurements.

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

Solution Approach 2:

The patent introduces temperature as an intermediary parameter between bearing damage and detection. Rather than directly measuring torque or vibration from damage, the system uses temperature distribution as an intermediate indicator. The evaluation device measures temperatures at multiple points around the bearing, and damage manifests as characteristic temperature patterns that are easier to detect than direct mechanical parameters.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If vibration or noise monitoring is used for early damage detection, then damage can be detected, but the methods require high measurement frequencies and expensive sensors

Engineering Contradiction:
Improveearly damage detection precisionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent substitutes vibration/acoustic measurement systems with thermal measurement systems. Instead of using complex vibration sensors requiring high measurement frequencies, the system uses temperature sensors to detect damage. The thermal field responds to friction changes caused by damage, providing a simpler measurement approach that avoids the complexities of high-frequency vibration analysis.

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

Solution Approach 2:

The patent changes the detection parameter from dynamic mechanical parameters (vibration, noise) to thermal parameters (temperature distribution). This parameter change transforms the detection problem from one requiring high-frequency measurements to one using steady-state or slowly varying temperature fields, which are easier to measure and evaluate with simpler equipment.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If single temperature measurement is used for bearing monitoring, then the system is simple, but the method is highly dependent on sensor position and unreliable

Engineering Contradiction:
Improvetemperature monitoring system complexityVSAvoiddamage detection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the temperature measurement into multiple spatial locations around the bearing. Instead of a single temperature sensor, the system employs multiple sensors positioned at different points (e.g., upper, lower, left, right sides of the bearing). This segmentation allows the system to capture the temperature distribution pattern, making detection reliable even if individual sensor positions vary, as the overall pattern remains characteristic of bearing conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from single-point temperature measurement to multi-point spatial temperature distribution measurement. By adding the spatial dimension to the measurement, the system evaluates temperature patterns across the bearing perimeter rather than at a single location. This dimensional expansion makes the measurement less sensitive to exact sensor positioning and provides more robust damage detection through pattern recognition.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Reliability

If multiple temperature sensors are distributed around the bearing circumference, then measurement reliability improves, but device complexity increases

Engineering Contradiction:
Improvetemperature measurement reliabilityVSAvoidsensor distribution complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent designs the temperature sensor system to serve multiple functions simultaneously. The distributed temperature sensors not only detect damage but also characterize the temperature distribution pattern, identify bearing location, and monitor overall thermal conditions. This multi-functionality justifies the increased sensor count by extracting multiple pieces of information from the same measurement infrastructure.

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

Solution Approach 2:

The patent uses multiple identical temperature sensors positioned at different locations around the bearing. Rather than using different types of sensors or complex measurement devices, the system employs simple, identical temperature sensors replicated at multiple positions. This copying approach maintains measurement reliability through redundancy while keeping individual sensor complexity low and evaluation straightforward through pattern comparison.

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

Provides a reliable, cost-effective method for early detection of damage in large rolling bearings by accurately measuring temperature distributions and comparing them to reference values, reducing unplanned downtime and maintenance costs.

Implementation Method 1

Damage, for example, to the bearing's running surface, always leads to increased friction in the affected area, and thus to a rise in temperature

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4264214B1System and method for thermal monitoring of a large rolling bearing
Publication Date: 2025.08.20 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP4264214B1 patent drawingFigure 1
  • EP4264214B1 patent drawingFigure 2
  • EP4264214B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a system for monitoring a rolling bearing, comprising the rolling bearing (1), at least three temperature sensors, wherein a first temperature sensor (2) is positioned in the surroundings of the rolling bearing (1) to detect an ambient temperature, a second temperature sensor (3) is positioned on a region (9) of the rolling bearing (1) under high load, preferably adjacent to a running surface of the rolling bearing (1), to detect a load temperature, and a third temperature sensor (4) is positioned on a region (10) of the rolling bearing (1) which is under less or no load, preferably adjacent to a running surface of the rolling bearing (1), to detect an idle temperature, and an analysis device (5) which is configured to analyze the state of the rolling bearing (1) on the basis of the temperatures detected.