Wheel Bearing Sensor Load Detection via Strain Segmentation
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Solution Overview
Problem
Existing sensor-equipped wheel support bearing assemblies face challenges in accurately detecting loads due to hysteresis from slippage and temperature influences, leading to reduced detecting resolution and accuracy.
Innovation Solution
A sensor-equipped wheel support bearing assembly with a strain generating member having multiple contact fixing segments and sensors arranged circumferentially, estimating load by calculating the difference between output signals from these sensors to counterbalance temperature and slippage effects, ensuring accurate load detection without hysteresis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a strain gauge is pasted to the outer ring of the bearing assembly for detecting strain, then the load detection function is achieved, but the assemblability deteriorates
Solution Approach 1:
The bearing assembly is divided into modular components: an outer ring, an inner ring, and a sensor unit. The sensor unit is further segmented into a strain generating member with multiple contact fixing segments and strain sensors. This segmentation allows the sensor unit to be pre-assembled and tested independently, then easily integrated into the bearing assembly, improving assemblability while maintaining detection accuracy.
Solution Approach 2:
A strain generating member is introduced as an intermediary component between the bearing structure and the strain sensors. This mediator converts the mechanical strain in the bearing into measurable strain in the strain generating member, which is then detected by the sensors. This intermediary approach simplifies the manufacturing process by allowing the sensor unit to be assembled separately and facilitates easier integration into the bearing assembly.
2Measurement precision
If the sensor unit is fixed to the stationary ring with contact fixing segments, then the load detection capability is improved, but the output signal fluctuates when rolling elements pass by
Solution Approach 1:
The sensor unit incorporates multiple contact fixing segments distributed around the stationary ring rather than a single fixed point. This segmentation allows the sensor to capture strain information from multiple locations, and by calculating the difference between outputs from sensors at different positions, the system can eliminate periodic fluctuations caused by rolling elements passing by specific locations.
Solution Approach 2:
The system uses the output signals from multiple strain sensors to compute a differential value that represents the actual load while canceling out periodic disturbances. This feedback mechanism continuously monitors and corrects for the fluctuations caused by rolling elements, maintaining signal stability and reliability.
3Measurement precision
If the flange portion deformation is used for load detection, then the load measurement is achieved, but hysteresis occurs in the output signal due to slippage
Solution Approach 1:
The strain generating member acts as an intermediary that is firmly coupled to the stationary ring through multiple contact fixing segments. This intermediary component directly measures the strain at the fixed position without being affected by slippage between the flange and knuckle surfaces, thereby eliminating hysteresis in the output signal while maintaining accurate load measurement capability.
Solution Approach 2:
The invention replaces the mechanical flange-knuckle contact system with a sensor-based measurement system. Instead of relying on the mechanical deformation and contact between flange and knuckle surfaces (which causes slippage and hysteresis), the strain sensors directly measure the strain in the stationary ring through the strain generating member, substituting mechanical contact measurement with direct strain sensing.
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 solution enables precise detection of vertical, driving, and axial loads by eliminating the impact of temperature and slippage, enhancing the accuracy and reliability of load measurement.
Implementation Method 1
a strain sensor fitted to this strain generating member... for detecting a strain induced in the strain generating member
Data Source
AI summary
A sensor-equipped wheel support bearing assembly capable of accurately detecting the load acting on the bearing assembly is provided. The sensor-equipped wheel support bearing assembly includes a sensor unit in an outer member that serves as a stationary member. The sensor unit includes a strain generating member, having two or more contact fixing segments to be fixed to the stationary member, and two or more sensors for detecting strain in the strain generating member. The contact fixing segments are spaced from each other in a direction circumferentially of the stationary member at the same axial positions. An estimating section is provided in the bearing assembly for estimating load thereon based on the difference between respective output signals from the sensors by calculating amplitudes of the output signals or values corresponding to such amplitudes from the difference between the respective output signals.