Plain Bearing Wear Monitoring via Gear Meshing Noise

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Solution Overview

Problem

Existing methods for monitoring the state of wear in plain bearings are complex, expensive, and face challenges due to limited installation space and the inability to effectively use structure-borne noise analysis, as plain bearings emit minimal noise and liquid friction interferes with noise-based damage detection.

Innovation Solution

A method that utilizes structure-borne noise from the meshing of gear wheels to assess the operating state of plain bearings by measuring and filtering noise signals with standard sensors placed outside the bearing, correlating the signals with physical parameters like bearing clearance, and using simulation models to determine the wear state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensors are placed directly in the plain bearing for temperature measurement or gap determination, then measurement precision is improved, but device complexity and installation space requirements worsen

Engineering Contradiction:
Improvewear state detection accuracyVSAvoidsensor installation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses structure-borne noise from gear meshing as an intermediary indicator to indirectly assess plain bearing wear. Instead of placing sensors directly in the bearing, the system measures noise generated by gear tooth contact, which is influenced by bearing gap changes. This mediator approach allows wear detection without direct bearing intervention, reducing installation complexity while maintaining diagnostic capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical sensing inside the bearing with acoustic/vibration-based measurement outside the bearing. By substituting mechanical contact sensors with structure-borne noise measurement, the system eliminates the need for intrusive installation while capturing wear-related changes through the mechanical chain from bearing gap to gear meshing noise

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

2Device complexity

If structure-borne noise measurement is used for plain bearing monitoring, then device complexity is reduced, but measurement precision worsens due to minimal noise emission and liquid friction interference

Engineering Contradiction:
Improvesensor installation simplicityVSAvoidwear state detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces gear meshing structure-borne noise as an intermediary that amplifies and transmits the effects of plain bearing wear. The gear meshing process generates characteristic noise patterns that are sensitive to bearing gap changes, serving as a natural amplifier that makes subtle bearing wear detectable through standard noise measurement techniques

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system establishes a feedback relationship where gear meshing noise provides continuous information about bearing wear state. By monitoring changes in structure-borne noise characteristics over time, the system creates a feedback loop that tracks bearing degradation, enabling precision measurement through cumulative pattern recognition rather than relying on strong single-point signals

Inventive Principle:
Principle #23Feedback

3Ease of manufacture

If standard sensors are used for structure-borne noise measurement, then manufacturing cost is reduced, but measurement precision worsens compared to specialized sensors

Engineering Contradiction:
Improvesensor availability and costVSAvoidwear state detection accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent makes the gear meshing process itself serve the measurement function by generating the structure-borne noise signal needed for wear detection. The normal operational meshing of gears, which would otherwise just transmit power, automatically produces the diagnostic signal, eliminating the need for specialized sensors while utilizing the system's own operational characteristics for self-diagnosis

Inventive Principle:
Principle #25Self-service

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 approach simplifies the assessment of plain bearing wear by using readily available sensors and filtering techniques, allowing for accurate determination of wear states without the need for specialized sensors or direct installation, while accounting for variables like gear speed and temperature.

Implementation Method 1

structure-borne noise occurs in the tooth meshing, that is to say in the meshing teeth of the first gear wheel and the second gear wheel. Structure-borne noise is sound that propagates in a body. In the present case, the structure-borne noise propagates in the first gear wheel and the second gear wheel and is transmitted to the surrounding transmission parts

Methodology Applied
Scientific EffectStructure-borne noise propagation: Sound

Data Source

PatentEP3775828B1Condition monitoring for plain bearings by means of structure-borne noise
Publication Date: 2022.09.07 ZF FRIEDRICHSHAFEN AG
  • EP3775828B1 patent drawingFigure 1

AI summary

The invention relates to a method for determining the operating condition of at least one plain bearing (107a, 107b), wherein: - a first gear (101) is rotatably mounted by means of the plain bearing (107a, 107b) and meshes with a second gear (103); and - structure-borne noise from toothed engagement of the first gear (101) and the second gear (103) is measured by means of a sensor (109). A quantity that correlates to an operating condition of the plain bearing (107a, 107b) is associated with a signal of the sensor (109).