Magnetostrictive Torque Sensor Magnetic Erasing Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing magnetostrictive torque sensors face accuracy issues due to shaft magnetization, which complicates the arrangement of demagnetization coils and increases the overall size and complexity of the sensor.
Innovation Solution
A magnetic erasing circuit is introduced to demagnetize the shaft using an alternate current generator and a switch to prevent mutual influence with the torque detecting device, ensuring accurate torque detection without affecting the sensor's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If demagnetization coils are added to erase shaft magnetization, then torque detection accuracy is improved, but device complexity and number of parts increase
Solution Approach 1:
The torque detection coils are made to serve dual functions: detecting torque during operation and demagnetizing the shaft when needed. By switching between detection mode and demagnetization mode, the same coils perform both functions, eliminating the need for separate demagnetization coils and reducing device complexity while maintaining torque detection accuracy
Solution Approach 2:
The patent combines the demagnetization function with the torque detection coils by connecting them in parallel through a switch. This merging of functions allows the system to use existing components for multiple purposes, reducing the overall number of parts and simplifying the sensor structure while still achieving accurate torque detection
2Measurement precision
If demagnetization coils are arranged on the shaft, then shaft magnetization is erased, but the overall size of the torque sensor increases
Solution Approach 1:
The torque detection coils perform dual functions as both detection elements and demagnetization coils, eliminating the need for additional dedicated demagnetization coils that would increase the sensor's overall size
Solution Approach 2:
By merging the demagnetization function into the existing torque detection coils, the patent avoids adding separate components that would increase the sensor's volume, thereby maintaining a compact design while achieving accurate torque detection
3Measurement precision
If magnetic erasing coils and torque detecting coils are arranged separately on the shaft, then demagnetization is effective, but the overall construction becomes complex
Solution Approach 1:
The torque detection coils are designed to serve as both detection coils and demagnetization coils by switching between operational modes. This multi-functionality eliminates the need for separate demagnetization coils and their associated mounting structures, thereby simplifying the overall construction while maintaining effective demagnetization and accurate torque detection
Solution Approach 2:
The patent combines the demagnetization function with the torque detection coils through parallel connection and switching. This merging approach consolidates components and simplifies the overall construction by eliminating redundant parts and reducing mounting complexity while achieving both demagnetization and detection functions
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
The solution improves torque detection accuracy, simplifies the sensor structure, and reduces the number of parts required, enhancing the precision and control of electric power steering systems.
Implementation Method 1
Magnetostriction is a well-known property of ferromagnetic materials that changes the shape of the materials due to stress or torque, wherein a magnetic field is changed.
Implementation Method 2
An example of such a magnetic material is Ni—Fe. The magnetostriction of the shaft is known to be erased by providing an alternate current provided to magnetic erasing coils surrounding the shaft.
Data Source
AI summary
A magnetostrictive torque sensor includes a magnetostrictive portion provided on a shaft. At least one torque detection coil is disposed opposite the shaft. The at least one torque detection coil detects a torque applied to the shaft. A demagnetization circuit (C) demagnetizes the shaft via the detecting coil.