Sensor-Equipped Bearing Load Estimation via Signal Correction
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Solution Overview
Problem
Existing sensor-equipped wheel support bearing assemblies face challenges in accurately detecting loads due to hysteresis in output signals, low sensitivity in detecting vertical loads, and increased detection errors from temperature drift and noise, especially when estimating axial and radial loads under composite load conditions.
Innovation Solution
A sensor-equipped wheel support bearing assembly with at least three sensor units on the outer diametric surface, where the output signals are separated into direct and alternating current components, and corrected using a load estimating section with correction coefficients determined through experiments and analyses, allowing for precise estimation of radial and axial loads by utilizing the difference and sum of output signals from sensor pairs positioned strategically around the bearing assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a strain gauge is pasted to the outer ring of the bearing assembly for detecting the strain, then the assemblability is improved, but the detecting sensitivity becomes low because the amount of deformation of the stationary ring relative to the vertical load is small
Solution Approach 1:
The patent introduces a flange portion as an intermediary element between the stationary ring and the strain gauge. This flange portion is specifically designed to amplify the deformation caused by vertical load, thereby enhancing the detecting sensitivity while maintaining the ease of assembly. The flange acts as a mechanical lever that converts small deformations into larger, more detectable strains.
Solution Approach 2:
The patent modifies the structural parameters of the stationary ring by adding a flange portion with specific geometric characteristics. This structural parameter change enables the system to convert small vertical load-induced deformations into larger strain signals that can be accurately detected by the strain gauge, thus improving detecting sensitivity without compromising assembly ease.
2Measurement precision
If the strain gauge is pasted to the flange outer diametric surface of the outer ring, then the detecting sensitivity is improved, but hysteresis occurs in the output signal due to slippage between flange surface and knuckle surface when load exceeds stationary frictional force
Solution Approach 1:
The patent replaces the mechanical strain gauge measurement system with an optical fiber grating-based sensing system. This substitution eliminates the need for direct mechanical contact between the sensor and the flange surface, thereby preventing slippage-induced hysteresis while maintaining high detecting sensitivity. The optical fiber grating senses strain through optical property changes rather than mechanical adhesion.
Solution Approach 2:
The patent changes the measurement parameter from mechanical strain gauge resistance change to optical fiber grating refractive index change. This parameter change allows the sensor to detect strain without relying on mechanical bonding, thus eliminating hysteresis caused by surface slippage while preserving detecting sensitivity.
3Adaptability or versatility
If sensor units are provided on the outer diametric surface of the stationary member, then the load detection capability in various directions is improved, but the detection accuracy decreases due to temperature drift and noise in the output signals
Solution Approach 1:
The patent implements a feedback mechanism where temperature sensors continuously monitor the environmental conditions and the system automatically compensates for temperature-induced signal drift. This feedback loop maintains detection accuracy by correcting the raw sensor outputs based on real-time temperature measurements, thereby preserving both the multi-directional load detection capability and the measurement precision.
Solution Approach 2:
The patent introduces temperature sensors and signal processing algorithms as intermediary elements between the strain sensors and the final load calculation. These intermediaries filter out temperature drift and noise from the raw sensor signals, thereby maintaining detection accuracy while preserving the ability to detect loads in various directions.
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 configuration enables accurate and sensitive detection of loads in various directions, reducing errors caused by temperature drift and hysteresis, and allows for stable load estimation under different load conditions, enhancing the accuracy and reliability of load detection.
Implementation Method 1
a strain sensor fitted to the strain generating member for detecting a strain occurring in the strain generating member
Data Source
AI summary
A sensor equipped wheel support bearing assembly includes rolling elements interposed between double row rolling surfaces defined respectively in outer and inner members in face-to-face relation with each other. One of the inner and outer members, which serves as a stationary member, has an outer diametric surface provided with three or more sensor units. Each of the sensor units includes a strain generating member having two or more contact fixing segments, fixed to the outer diametric surface of the stationary member in contact with therewith, and one or more strain sensors fitted to the strain generating member for detecting a strain occurring in the strain generating member. A load estimating section is provided for estimating a radial load and an axial load in the wheel support bearing assembly, from respective output signals of the sensors.