Magnetic Sensor Range Extension via Support Field Segmentation
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Solution Overview
Problem
Existing magneto-sensitive sensor arrangements have a limited functional range due to strong scattering of magnetic field lines, resulting in insufficient detection of field changes at distances greater than 5 mm, which restricts their sensitivity and effective distance for measuring objects.
Innovation Solution
A supporting magnet is placed at a distance from the sensor magnet to bundle magnetic field lines in a preferred direction, allowing the measurement object to be positioned at greater distances, thereby increasing the magnetic flux density and sensitivity of the sensor arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor magnet is spatially enlarged to generate stronger field lines at greater distances, then the magnetic flux density at distance is improved, but the available installation space deteriorates
Solution Approach 1:
The magnetic field generation function is segmented between two separate magnets: the sensor magnet (which remains small and close to the sensor) and the supporting magnet (which is positioned at a distance to extend the field). This segmentation allows the sensor magnet to stay compact while the supporting magnet provides the necessary field extension, resolving the contradiction between field strength at distance and installation space.
Solution Approach 2:
The supporting magnet acts as an intermediary element that mediates the magnetic field between the sensor magnet and the measurement object. By positioning this intermediary magnet at an optimal distance, the magnetic flux density is enhanced at the measurement object location without requiring the sensor magnet itself to be enlarged, thus maintaining compact installation space.
2Length of stationary object
If the distance between sensor magnet and measurement object is increased beyond 5 mm, then the functional range is improved, but the magnetic flux density deteriorates due to strong scattering of field lines
Solution Approach 1:
The magnetic field path is segmented into two zones: near-field (sensor magnet to supporting magnet) and far-field (supporting magnet to measurement object). The supporting magnet is positioned to create a focused field in the far-field zone, compensating for the natural scattering that occurs over distance and maintaining sufficient flux density at extended ranges.
Solution Approach 2:
The spatial parameters of the magnetic field are changed by introducing the supporting magnet at a specific distance and orientation. This alters the field distribution pattern, creating a more directed and less scattered field configuration that maintains higher flux density at greater distances from the sensor magnet.
3Measurement precision
If special magnetic materials are used to achieve stronger field lines with the same magnet size, then the magnetic flux density is improved, but the manufacturing cost and complexity deteriorate
Solution Approach 1:
Instead of using expensive special magnetic materials, the patent uses a configuration of standard magnets that replicates the field-enhancing effect. The supporting magnet creates a field pattern that copies or mimics what would be achieved with enhanced materials, but through geometric arrangement rather than material properties, reducing manufacturing cost and complexity.
Solution Approach 2:
The patent employs conventional, readily available magnetic materials for both the sensor magnet and supporting magnet rather than investing in expensive special materials. This approach uses inexpensive, easily manufactured components to achieve the desired field characteristics through clever positioning and configuration.
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 significantly expands the effective range of the sensor arrangement, enabling detection of field changes at distances up to 20 mm, enhancing sensitivity and flexibility in arranging the magnets and measurement object, while allowing for both linear and rotary movement detection.
Implementation Method 1
field lines F moving from the sensor magnet 2 starting from the north pole N in the direction of the south pole S
Implementation Method 2
an associated magneto-sensitive sensor 3 (for example a Hall sensor)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The arrangement (1) has sensor magnets (2), and a magneto-sensitive sensor (3) e.g. hall sensor, cooperating with the sensor magnets. A measuring object is movably arranged adjacent to the sensor. A support magnet (4) is arranged adjacent to the sensor magnets, where the object is movably arranged between the magnets (2, 4) and in distance to the sensor magnets. The sensor magnets and/or the support magnet is designed as a permanent magnet or an electro magnet and is made of plastic.