Magnetic Flux Balancing in Rotation Angle Sensors
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Solution Overview
Problem
Existing rotation angle detecting devices face accuracy issues due to significant bias in magnetic flux densities detected by magnetic sensors, leading to distorted arctan values and increased error in rotation angle detection, especially when the magnetic flux has difficulty passing through the sensor in certain directions.
Innovation Solution
A rotation angle detecting device is designed with a sensor magnet having multiple magnetic poles in the circumferential direction and a pair of magnetic parts that sandwich the magnetic sensor in a direction orthogonal to the sensor's primary detection axis, ensuring balanced magnetic flux density detection and reducing the need for extensive correction processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnetic sensor is arranged in a conventional position relative to the sensor magnet, then the device structure is simple, but the magnetic flux density detection becomes distorted and detection accuracy decreases
Solution Approach 1:
A pair of magnetic parts is introduced as intermediary elements between the sensor magnet and the magnetic sensor. These magnetic parts mediate the magnetic flux transmission, guiding the flux to pass through the magnetic sensor more uniformly in both detection directions, thereby reducing detection distortion and improving measurement precision without fundamentally changing the overall device structure
Solution Approach 2:
The magnetic parts are positioned specifically at locations where magnetic flux guidance is needed, creating localized magnetic flux concentration and uniformity. This local modification optimizes the magnetic field distribution in the critical detection region without requiring global structural changes, thus improving detection accuracy while maintaining structural simplicity
2Measurement precision
If correction processing is applied to compensate for magnetic flux bias, then detection accuracy may be maintained, but the computational load increases and error may increase
Solution Approach 1:
The magnetic parts are pre-positioned to establish optimal magnetic flux paths before detection begins. This preliminary structural arrangement ensures that magnetic flux densities are naturally balanced in both detection directions from the start, eliminating the need for subsequent correction processing and reducing computational complexity
Solution Approach 2:
Instead of treating the magnetic flux directionality issue as a problem requiring correction, the invention uses the magnetic parts to convert this characteristic into a benefit by naturally guiding and balancing the magnetic flux distribution. This transforms what would be a source of detection error into an advantage that simplifies the detection process
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 maintains a nearly linear change in arctan values with respect to rotation angle, decreasing detection errors and computational load, while enhancing the accuracy and ease of rotation angle detection.
Implementation Method 1
a magnetic sensor, overlapped with the sensor magnet when viewed in a predetermined first direction and capable of detecting a magnetic field of the sensor magnet
Implementation Method 2
a pair of magnetic parts, provided to sandwich the magnetic sensor in a second direction intersecting the first direction
Data Source
AI summary
An aspect of the disclosure provides a rotation angle detecting device capable of detecting a rotation angle of a rotation body rotatable about a central axis. The rotation angle detecting device includes: a sensor magnet, having multiple magnetic poles provided side-by side in a circumferential direction about the central axis and installed to the rotation body; a magnetic sensor, overlapped with the sensor magnet when viewed in a predetermined first direction and capable of detecting a magnetic field of the sensor magnet; and a pair of magnetic parts, provided to sandwich the magnetic sensor in a second direction intersecting the first direction.