Sensor Device Dual Magnet Arrangement Stray Field Robustness
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Solution Overview
Problem
Existing sensor devices face challenges in accurately determining the position of a sensor element within a magnetic field, especially in the presence of external stray fields and achieving consistent measurements over large displacements, while maintaining a cost-effective and structurally simple design.
Innovation Solution
The sensor device employs two magnet arrangements with different magnetic field orientations along the direction of movement, allowing for clear position detection through differential signal processing, and incorporates sensors positioned to monitor these arrangements effectively, enabling precise position determination and robustness against external fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single magnet arrangement is used, then the device complexity is low, but the position determination becomes ambiguous in the presence of external stray fields
Solution Approach 1:
The magnet arrangement is segmented into multiple independent magnets with different polarities (first polarity and second polarity) arranged along the direction of movement. Each magnet generates a magnetic field that can be independently detected by the sensors, allowing for more precise position determination through differential measurement while maintaining relatively simple individual magnet structures.
Solution Approach 2:
Different regions of the magnet arrangement have different magnetic pole configurations. The first magnet has a first polarity and the second magnet has a second polarity, creating locally differentiated magnetic field characteristics. This allows the sensors to detect position information by comparing the differential signals from different magnetic field regions, improving measurement precision without requiring a completely complex overall structure.
2Measurement precision
If multiple sensors are used to detect magnetic fields, then the position detection precision improves, but the device complexity and cost increase
Solution Approach 1:
Multiple magnetic field sensors are combined in a differential configuration where they simultaneously detect magnetic fields from multiple magnets. The evaluation unit processes the signals from all sensors differentially, extracting position information from the combined magnetic field patterns. This merging approach achieves high precision position detection while sharing the sensor infrastructure across multiple measurement functions.
Solution Approach 2:
The array of magnetic field sensors serves multiple functions: detecting magnetic fields from different magnets, providing differential measurement capability, and enabling position determination through signal comparison. The same sensor array is used to detect both the first magnetic field and the second magnetic field, making the sensor system multi-functional rather than requiring separate sensor sets for each magnet.
3Measurement precision
If magnets with different polarities are arranged along the movement direction, then the position determination accuracy improves, but the manufacturing complexity increases
Solution Approach 1:
The magnet arrangement is divided into separate, discrete magnet segments (first magnet, second magnet, etc.) that can be manufactured independently using standard magnet manufacturing processes. Each segment has a defined polarity and can be produced using conventional techniques, then assembled in the required sequence along the direction of movement, simplifying the overall manufacturing process compared to creating a single complex magnet structure.
Solution Approach 2:
Each magnet segment is manufactured with a specific local magnetic polarity characteristic (first polarity or second polarity) that is optimized for its position in the array. This allows standard manufacturing processes to produce each segment with its required polarity, and the segments are then assembled in the appropriate sequence to create the overall differential magnetic field pattern, making the manufacturing process more manageable.
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 ensures unambiguous position determination, high resolution, and cost-effective implementation, with the ability to detect both linear and rotary movements, while maintaining a compact and structurally simple design.
Implementation Method 1
at least two magnetic field-sensitive sensors fixed to the housing for determining a position and/or displacement of the sensor element, the sensor element having a first magnet arrangement that varies along the direction of movement of the sensor element aligned magnetic fields
Data Source
Figure 1
AI summary
The invention relates to a sensor device (1) having an encoder element (2), which can be displaced in a direction of movement, and having at least two housing-affixed, magnetic field-sensitive sensors (3) for determining a position and/or movement of the encoder element (2), wherein the encoder element (2) has a first magnet arrangement (6), which has differently aligned magnetic fields along the direction of movement of the encoder element. According to the invention, the encoder element (2) has a second magnet arrangement (7), which has differently aligned magnetic fields along the direction of movement of the encoder element (2).