AMR Sensor Array Magnetic Design for Air Gap Tolerance
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Solution Overview
Problem
Conventional Anisotropic Magnetoresistive (AMR) position sensing systems experience decreased performance and repeatability due to changes in the air gap between the magnet and sensors, affecting the accuracy of position detection.
Innovation Solution
An AMR array magnetic position sensing system is designed with a pair of magnets enclosed in a magnet carrier, generating uniform magnetic flux lines that are sensed by external AMR position sensors, reducing susceptibility to air gap variations and improving sensor flexibility and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the air gap between the magnet and AMR position sensors is changed, then the sensor flexibility and adaptability are improved, but the measurement precision and repeatability deteriorate
Solution Approach 1:
The patent changes the magnetic flux distribution parameters by using a pair of magnets arranged in specific configurations (e.g., alternating polarity patterns) to create a magnetic field where flux lines remain substantially perpendicular to the AMR sensor runners across varying air gaps. This parameter change in magnetic field geometry resolves the contradiction by maintaining measurement precision while allowing air gap variation for sensor flexibility.
Solution Approach 2:
The patent transitions from a single magnet configuration to a pair of magnets arranged in a specific spatial dimension, creating a magnetic field pattern that extends uniformly across the sensor array. This dimensional change in magnetic field architecture ensures that flux lines remain perpendicular to sensor runners regardless of air gap changes, simultaneously achieving adaptability and precision.
2Device complexity
If conventional single magnet configuration is used, then the device complexity is reduced, but the reliability under varying air gap conditions deteriorates
Solution Approach 1:
The patent divides the magnetic field generation function into multiple segments by using a pair of magnets instead of a single magnet. Each magnet is positioned to contribute to a unified magnetic field pattern where flux lines remain perpendicular to the AMR sensor runners across varying air gaps, thereby improving reliability while maintaining reasonable device complexity.
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 system enhances the accuracy and reliability of position sensing by minimizing the impact of air gap changes on the sensor output signals, maintaining consistent performance across varying distances.
Implementation Method 1
Anisotropic Magnetoresistance (AMR) is the property of a material in which the electrical resistance can change depending on the angle between the direction of electrical current and orientation of magnetic field is observed.
Implementation Method 2
The magnet 110 generates magnetic flux lines 120 while moving in the direction as indicated by arrow 140.
Data Source
AI summary
An AMR array magnetic position sensing system for improved sensor flexibility and improved air gap performance is disclosed. A pair of magnets can be enclosed in a magnet carrier that moves along a path and located above an array of AMR position sensors. The magnets are generally magnetized through the length of the magnets, and the magnets are positioned in the carrier such that an angle between the magnets exists in a manner similar to an angle made by AMR runners on a surface of the AMR positions sensors to create magnetic flux lines thereof. The AMR position sensors come into contact with the uniform magnetic flux lines to sense a change in linear and angular position associated with the magnet carrier. The output signal generated by the AMR position sensors have less susceptibility to variations in air gap as the angles of the magnetic flux lines generated by the magnets do note change with respect to air gap variation.