Magnetic Angle Encoder Using Cylindrical Ring Permanent Magnets
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Solution Overview
Problem
Existing magnetic angle encoders are not compatible with tunneling magnetoresistive sensors due to differences in magnetic field detection orientation and cylindrical permanent magnet designs, which are not suitable for counting wheels in electronic water meters, leading to issues with measurement accuracy and space utilization.
Innovation Solution
A cylindrical ring permanent magnet structure with two permanent magnet units, aligned either oppositely or perpendicularly, is integrated into the counting wheel, allowing tunneling magnetoresistive sensors to detect a magnetic field component that varies linearly with the rotation angle, enabling improved measurement accuracy and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional cylindrical permanent magnets are used in magnetic angle encoders, then the structure is simple, but they are not compatible with tunneling magnetoresistive sensors and cannot be integrated into counting wheels of electronic water meters
Solution Approach 1:
The permanent magnet is divided into two separate permanent magnet units arranged side by side, each generating magnetic fields in different directions. This segmentation allows the magnet system to be compatible with tunneling magnetoresistive sensors while maintaining structural simplicity for integration into counting wheels.
Solution Approach 2:
The patent transitions from a single cylindrical magnet to a two-unit configuration where magnetic fields are generated in different spatial dimensions (one unit for vertical field, one for horizontal field). This dimensional change enables compatibility with tunneling magnetoresistive sensors that require specific field orientations.
2Measurement precision
If existing permanent magnet designs are used, then manufacturing is straightforward, but measurement accuracy is compromised due to non-linear relationship between magnet angle and magnetic field angle
Solution Approach 1:
The patent changes the magnetic field parameters by using two permanent magnet units with different magnetization directions. This allows the magnetic field angle to have a linear relationship with the rotation angle of the permanent magnet, improving measurement accuracy while maintaining ease of manufacture through standard magnetization processes.
3Volume of moving object
If compact designs are pursued for electronic water meters, then space utilization improves, but sensor position sensitivity increases making the system more fragile
Solution Approach 1:
The two permanent magnet units work together to provide both compactness and reduced sensor position sensitivity. The combined magnetic field configuration allows the system to maintain reliability while achieving compact design suitable for electronic water meters.
4Adaptability or versatility
If Hall sensors are used to detect magnetic fields, then the detection orientation is perpendicular to sensor surface, but this is not compatible with tunneling magnetoresistive sensors that require parallel detection
Solution Approach 1:
Each permanent magnet unit is designed with specific local magnetic field characteristics (one for vertical field, one for horizontal field) to match the detection requirements of tunneling magnetoresistive sensors. This local quality approach enables sensor compatibility while keeping the overall system relatively simple.
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 cylindrical ring permanent magnet design enhances measurement accuracy, allows for direct integration into existing counting wheel structures, reduces sensor position sensitivity, and enables smaller size electronic water meters with precise angle detection.
Implementation Method 1
a cylindrical ring permanent magnet structure... allowing tunneling magnetoresistive sensors to detect a magnetic field component that varies linearly with the rotation angle
Implementation Method 2
tunneling magnetoresistive sensors... used to detect the magnetic field produced by permanent magnets
Data Source
AI summary
A magnetic angle encoder comprising counting wheels, with columnar ring-shaped permanent magnets coaxially mounted to the counting wheels, tunneling magnetoresistive angular displacement sensors, and a digital processing circuit. In the magnetic angle encoder, the tunneling magnetoresistive angular displacement sensors are located in a region within detection planes of the permanent magnets with an axial distance and a specific radial distance from the permanent magnets. Within this specific radius range, the rotating magnetic field angle (Φ) of the component of the magnetic field generated by the permanent magnets in the detection planes varies linearly with the rotation phase angle (α) of the permanent magnets. An electronic water meter is also disclosed, and it comprises a plurality of counting units and a digital processing circuit. The counting units contain counting wheels, permanent magnets, and tunneling magnetoresistive angular displacement sensors. The digital processing circuit is connected to each tunneling magnetoresistive angular displacement sensor, and converts the output of the tunneling magnetoresistive angular displacement sensors into a digital code. The magnetic angle encoder and the electronic water meter have the advantages of small size and high measurement accuracy.