Rolling Device Lubrication Diagnosis via Impedance and Dielectric Sensing
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Solution Overview
Problem
Existing methods for diagnosing the lubrication state of rolling devices, such as bearings, can only measure oil film thickness and struggle to accurately assess other critical factors like metal contact ratio and dielectric constant, limiting their effectiveness in maintaining optimal lubrication.
Innovation Solution
A diagnostic method that applies an AC voltage to an electric circuit including the outer and inner members of a rolling device, measures impedance and phase angle, calculates the dielectric constant of the lubricant, and determines wear powder concentration to comprehensively assess the lubrication state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an AC voltage is applied to measure oil film thickness using electrostatic capacity, then the oil film thickness can be measured, but other elements affecting lubrication state such as metal contact ratio and dielectric constant cannot be grasped
Solution Approach 1:
The measurement process is segmented into multiple independent measurement steps: first measuring impedance to obtain oil film thickness, then measuring phase angle to obtain dielectric constant, and combining these with metal contact ratio to comprehensively assess lubrication state. This segmentation allows each parameter to be measured and analyzed separately while contributing to the overall diagnostic picture.
Solution Approach 2:
The invention transitions from a single-dimensional measurement (electrostatic capacity for oil film thickness) to a multi-dimensional measurement approach by incorporating impedance magnitude and phase angle as additional measurement dimensions. This enables extraction of multiple lubrication parameters (oil film thickness, dielectric constant, metal contact ratio) from the same measurement system, comprehensively characterizing the lubrication state.
2Device complexity
If only electrostatic capacity is measured to estimate oil film state, then the measurement method is simple, but the diagnosis of lubrication state is insufficient
Solution Approach 1:
The impedance measurement system is designed to perform multiple diagnostic functions using the same hardware configuration. By measuring both the magnitude (impedance) and phase angle of the impedance, the system can simultaneously determine oil film thickness, dielectric constant, and metal contact ratio, making the measurement system universally applicable for comprehensive lubrication state assessment without requiring additional specialized equipment.
Solution Approach 2:
The invention utilizes changes in electrical parameters (impedance magnitude and phase angle) in response to variations in lubrication conditions. As the lubrication state changes (oil film thickness, dielectric constant, metal contact ratio), the impedance parameters change accordingly. By monitoring these parameter changes, the system can reliably diagnose the lubrication state while maintaining a relatively simple measurement approach.
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 method allows for a more accurate diagnosis of the lubrication state by considering oil film thickness, metal contact ratio, and dielectric constant, enabling better maintenance timing and reducing wear-related issues.
Implementation Method 1
measuring an impedance and a phase angle of the electric circuit when the AC voltage is applied
Implementation Method 2
measuring a dielectric constant of a lubricant at least one of between the outer member and the rolling element and between the inner member and the rolling element based on the measured impedance and the measured phase angle
Implementation Method 3
an AC voltage is applied to a rotating wheel of a rolling device in a non-contact state, and an electrostatic capacity of the oil film is measured
Data Source
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AI summary
A method for diagnosing a rolling device (10) including an outer member (1), an inner member (3), and rolling elements (5) includes: applying an AC voltage to an electric circuit including the outer member (1), the rolling elements (5), and the inner member (3); measuring an impedance and a phase angle of the electric circuit when the AC voltage is applied; and measuring a dielectric constant of a lubricant at least one of between the outer member (1) and the rolling elements (5) and between the inner member (3) and the rolling elements (5) based on the measured impedance and the measured phase angle.