Wheel Bearing Sensor Load Estimation Dynamics
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Solution Overview
Problem
Existing sensor-equipped wheel support bearing assemblies face challenges in accurately estimating loads without causing discontinuous changes in the estimated load value, particularly when wheel rotation speed information is unavailable, leading to detection errors and increased time delays.
Innovation Solution
A sensor-equipped wheel support bearing assembly that includes a strain generator member with multiple fixation contact segments and sensors to estimate loads using both average and amplitude values of sensor output signals, with a summation ratio that adjusts based on wheel rotation speed, allowing for continuous load estimation without relying on rotation speed information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If load estimation is performed using amplitude value of sensor output signals, then load estimation accuracy is improved, but detection time delay increases and discontinuous changes occur at low wheel rotation speeds
Solution Approach 1:
The patent applies dynamics by making the load estimation method adaptive to wheel rotation speed conditions. The ECU dynamically switches between amplitude-value-based estimation (for high-speed accuracy) and average-value-based estimation (for low-speed continuity), ensuring optimal performance across varying operational conditions without fixed limitations.
Solution Approach 2:
The patent changes the parameter used for load estimation based on wheel rotation speed. At high rotation speeds, amplitude value parameters are utilized for accurate load estimation. At low rotation speeds, the system transitions to using average value parameters, preventing discontinuous changes and excessive time delays while maintaining acceptable estimation accuracy.
2Measurement precision
If load estimation relies on wheel rotation speed information, then detection accuracy is improved, but system reliability deteriorates when rotation speed information is unavailable
Solution Approach 1:
The patent extracts the dependency on wheel rotation speed information from the load estimation system. By using amplitude and average values of sensor output signals directly, the system achieves accurate load estimation without requiring external rotation speed data, thereby maintaining reliability even when such information is unavailable.
Solution Approach 2:
The system performs self-service by utilizing its own sensor output signals (amplitude and average values) for load estimation purposes. This self-contained approach eliminates the need for external wheel rotation speed information, ensuring the system can independently determine load conditions under all operational circumstances.
3Device complexity
If strain gauge is affixed on outer ring to sense strain, then device complexity is reduced, but measurement precision deteriorates due to inadequate deformation of stationary member
Solution Approach 1:
The patent introduces an intermediary mechanism (the bearing assembly structure itself) that amplifies and transmits deformation to the strain gauge. By positioning the strain gauge to sense deformation in critical load-bearing components, the system achieves high measurement precision without increasing overall device complexity, as the bearing structure naturally serves as the deformation intermediary.
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 minimizes detection time delays, reduces load estimation errors, and ensures continuous, accurate load calculation even at low wheel rotation speeds or when rotation speed information is unavailable, enhancing control system performance.
Implementation Method 1
a sensor fitted to the strain generating member for detecting a strain occurring in the strain generating member
Data Source
AI summary
Provided is a sensor-equipped wheel support bearing assembly for rotatably supporting a wheel, including a sensor unit associated with one of outer and inner members that serve as a stationary member. The sensor unit includes a strain generator member that has at least three fixation contact segments fixedly in contact with the stationary member and at least two strain sensors mounted on the strain generator member. A first load estimator is provided to estimate load acting on the bearing assembly, using an average value of output signals of the sensors. A second load estimator is provided to estimate load acting on the bearing assembly, using the average value and an amplitude value of output signals of the sensors. An estimated load provider is provided to sum these outputs from the load estimators in a ratio that depends on wheel rotation speed, for outputting an estimated load.