Magnetoresistive Motion Detection With Segmented Transmitter Magnetization
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Solution Overview
Problem
Existing devices for contactlessly detecting rotational or linear movements face challenges due to geometric constraints, particularly in rolling bearings, where the positioning of the sensor is compromised by strong transverse magnetic fields, leading to unreliable detection of rotational movements.
Innovation Solution
The transmitter sections are magnetized over a length shorter than their extent in the third spatial direction, allowing for adaptable positioning of the sensor to minimize interference from transverse magnetic fields, thus decoupling geometric requirements and enabling reliable detection of movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmitter sections are magnetized over their full extent in the third spatial direction, then the geometric requirements for sealing and structural functions are met, but strong transverse magnetic fields are generated that disrupt sensor detection
Solution Approach 1:
The transmitter sections are segmented in terms of magnetization: only a portion of each section's extent in the third spatial direction is magnetized, creating a magnetized length shorter than the full extent. This segmentation allows the non-magnetized portions to fulfill sealing and structural functions without generating interfering transverse magnetic fields, while the magnetized portions provide the necessary magnetic field for detection.
Solution Approach 2:
Different regions of the transmitter sections are assigned different magnetic properties: the central region is magnetized to produce the detection field, while the edge regions remain non-magnetized to minimize transverse field interference. This local differentiation of magnetic quality resolves the contradiction between detection reliability and transverse field interference.
2Measurement precision
If the sensor is positioned close to the transmitter for accurate detection, then detection precision improves, but the sensor is exposed to stronger transverse magnetic fields that disrupt measurement
Solution Approach 1:
The transmitter's magnetization is segmented to create a magnetic field distribution where the useful field components are strong near the transmitter while the harmful transverse field components are minimized. This allows the sensor to be positioned close to the transmitter for accurate detection without being overwhelmed by interfering transverse fields.
3Reliability
If the transmitter geometry is optimized for sealing functions in rolling bearings, then the sealing performance is improved, but the sensor positioning becomes constrained and detection reliability decreases
Solution Approach 1:
The transmitter sections are segmented into magnetized and non-magnetized regions, allowing the overall geometry to be optimized for sealing functions while only the necessary central portion is magnetized. This enables the transmitter to fulfill both sealing and detection functions simultaneously, resolving the contradiction between sealing performance and detection precision.
Solution Approach 2:
The transmitter exhibits local quality differentiation where the central region provides magnetic field generation for detection while the outer regions provide sealing functionality. This local functional differentiation allows optimal sensor positioning and detection precision without compromising sealing performance.
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 approach allows for flexible sensor positioning and reduced interference from transverse magnetic fields, ensuring reliable detection of rotational or linear movements in various installation situations, including those with complex geometries like rolling bearings.
Implementation Method 1
a stationary magnetoresistive sensor and a transmitter
Implementation Method 2
This creates a magnetic field between the alternatingly magnetized sections, which magnetic field has field components in all spatial directions
Data Source
AI summary
A device for detecting rotational or linear movements includes a transmitter with sections, and a magnetoresistive sensor. The sections are alternatingly inversely magnetized along a trajectory extending in a first spatial direction. The sections includes respective magnetic poles that oppose each other in a second spatial direction, orthogonal to the first spatial direction, and an extent in a third spatial direction orthogonal to the first spatial direction and to the second spatial direction. The sections are magnetized over a length in the third spatial direction that is less than the extent. The magnetoresistive sensor is spaced from the transmitter by a gap in the second spatial direction, and the magnetoresistive sensor is stationary. The spatial directions may be directions in a cylindrical coordinate system or a cartesian coordinate system.