Bearing Surface Defect Estimation via Strain Sensors
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Solution Overview
Problem
Existing acceleration-based vibration condition monitoring methods for bearings suffer from poor scalability and reproducibility across different machines and machine designs, and are not robust in real-world conditions due to disturbances and deteriorated vibration transfer paths, making it difficult to accurately evaluate defect severity and detect surface defects.
Innovation Solution
A method using strain sensors to measure strain values caused by rolling element forces, determining cyclostationary contact forces through linear equations and basis functions, and comparing these forces to a detection threshold to estimate the size of surface defects, which provides better visibility of defects and predicts risk of failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acceleration-based vibration sensors are used for condition monitoring, then defect detection capability is provided, but measurement precision deteriorates due to disturbances and deteriorated vibration transfer paths in real-world conditions
Solution Approach 1:
The patent introduces strain sensors as an intermediary measurement device that directly measures mechanical strain at the bearing location, bypassing the problematic vibration transfer path. This mediator (strain sensor) provides a more direct and reliable measurement of bearing condition without being affected by the same transfer path issues that plague acceleration-based vibration sensors.
Solution Approach 2:
The patent replaces the acceleration-based vibration measurement system with a strain-based mechanical measurement system. By substituting the measurement principle from acceleration (which requires complex signal processing and is sensitive to transfer path issues) to direct strain measurement, the system achieves more reliable defect detection in real-world conditions.
2Reliability
If acceleration-based vibration monitoring is implemented, then defect identification is enabled, but reliability decreases due to poor scalability and reproducibility across different machines
Solution Approach 1:
The patent creates a universal monitoring solution based on strain measurement that can be applied across different machine types and bearing configurations. The strain sensor approach provides a standardized measurement method that scales reliably from one machine to another, unlike acceleration-based methods that require machine-specific calibration and show poor reproducibility.
3Measurement precision
If vibration signals are processed to evaluate defect severity, then defect size estimation is attempted, but measurement precision deteriorates due to hidden defect signatures in real conditions
Solution Approach 1:
The patent extracts the critical measurement information (strain) directly from the bearing location using strain sensors, separating the measurement from the problematic vibration signal path. This extraction of the essential mechanical stress information eliminates the information loss that occurs when defect signatures are hidden by disturbances in the vibration transfer path.
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 enhances the accuracy of condition monitoring by effectively detecting and sizing surface defects, improving the robustness of defect severity evaluation and predicting bearing failure risk, even in complex real-world conditions.
Implementation Method 1
measuring, with at least one strain sensor comprising a detection cell, the length of the detection cell of the sensor in a circumferential direction being smaller than the circumferential distance between two adjacent rolling elements projected on the stationary ring, strain values caused by rolling element forces on the stationary ring
Data Source
AI summary
A device (8) for estimating the size of a surface defect of a bearing (6). The device (8) includes a conditioning means (13), a first determining means (14), a second determining means (15), a solving means (16), a comparing means (17), a detecting means (18), and a third determining means (19).