Wheel Bearing Load Estimation via Strain Amplification
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Solution Overview
Problem
Existing sensor-equipped wheel support bearing assemblies face challenges in accurately detecting loads under low-speed or stationary conditions due to small strain deformations and increased complexity and costs with multiple sensors, leading to discontinuous load estimation errors in control systems.
Innovation Solution
A novel load estimating unit is introduced, utilizing a first and second calculating equation based on average and amplitude values of sensor outputs, with parameter switching depending on rotational speed and evaluation values, and a correction mechanism to ensure continuous load estimation by combining results within predetermined regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a strain gauge is pasted to the outer ring of the wheel support bearing assembly to detect load, then the structure is simple, but the detection accuracy is insufficient due to small strain deformation
Solution Approach 1:
A strain generating member is introduced as an intermediary component between the bearing assembly and the sensor. This member amplifies the small strain deformation of the bearing into larger strain that can be accurately detected by the sensor, thereby improving measurement precision while maintaining structural simplicity
Solution Approach 2:
The strain generating member changes the strain parameter by amplifying the deformation magnitude. The member is designed with specific geometric features that convert small bearing strain into larger, more detectable strain values, improving the sensor's ability to accurately measure load
2Measurement precision
If multiple sensor units are disposed at different positions to detect load under various conditions, then the detection accuracy improves, but the device complexity and cost increase
Solution Approach 1:
The strain generating member is divided into multiple contact fixing segments that contact different portions of the bearing assembly. This segmentation allows a single sensor to detect strain from multiple load paths, achieving comprehensive load detection without requiring multiple separate sensors
Solution Approach 2:
The strain generating member serves multiple functions: it amplifies strain, distributes load to multiple contact points, and enables a single sensor to detect various types of loading conditions. This multi-functionality reduces the need for multiple specialized sensors
3Measurement precision
If parameter switching is performed based on rotational speed to improve load estimation accuracy, then the detection accuracy improves, but discontinuous changes may occur causing errors in control systems
Solution Approach 1:
Predetermined regions and transition rules are established in advance for parameter switching. These pre-defined parameters ensure smooth transitions between different operating conditions, preventing discontinuous changes in load estimation that could affect control system reliability
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 reduces load estimation errors and provides continuous, accurate load detection across various conditions, enhancing reliability and compatibility with control systems by correcting non-linear sensor characteristics and minimizing discontinuous changes.
Implementation Method 1
a sensor fitted to the strain generating member for detecting the strain induced in the strain generating member
Data Source
AI summary
A sensor equipped wheel support bearing assembly, in which a continuous estimated load can be obtained depending on various inputted load conditions is provided. The sensor equipped wheel support bearing assembly includes a sensor unit provided in a stationary member, and a load estimating unit. The load estimating unit includes a load estimation calculating section for calculating the load using an estimation calculating equation, an evaluation value calculation section for calculating an evaluation value, which provides a parameter switching index in the estimation calculating equation, from sensor output signals, and a parameter switching section for switching the parameter based on a comparison result of the evaluation value with a threshold value. The load estimation calculating section includes a calculation correcting block for correcting the calculation result on both sides of the threshold value within a predetermined evaluation value region containing the threshold value.