Magnetic Field Sensor Assembly for Long Path Measurement
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Solution Overview
Problem
Conventional sensor assemblies for measuring long paths or angles require two large magnets, which is not feasible in all construction spaces and is expensive, making it difficult to integrate sensitive magnetic field sensors effectively.
Innovation Solution
A sensor assembly with a small, cost-effective magnet placed in the fixed part of the application, using a combination of an active magnet on the movable component and an auxiliary magnet in the fixed part to generate a rotating and constant magnetic field vector, respectively, allowing for precise measurement with reduced space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two large magnets are used on the movable component to measure long paths, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The magnetic field generation is segmented between two separate magnets: a first magnet on the movable component and a second magnet in the fixed sensor housing. This segmentation allows each magnet to be smaller and more cost-effective while collectively providing the magnetic field necessary for precise long-path measurement.
Solution Approach 2:
The second magnet in the fixed sensor housing acts as an intermediary that provides a stationary magnetic field component. This intermediary magnet enables the movable first magnet to generate a rotating magnetic field vector when the component moves, allowing precise position detection without requiring the movable magnet alone to provide the complete magnetic field.
2Measurement precision
If two large magnets are used on the movable component, then long path measurement is enabled, but installation space requirements increase
Solution Approach 1:
By segmenting the magnetic field generation between a movable first magnet and a fixed second magnet, the volume requirement for the movable component is reduced. The first magnet on the movable component can be smaller since it only needs to interact with the fixed second magnet to generate the necessary magnetic field changes for long-path measurement.
Solution Approach 2:
The solution moves one magnet from the movable dimension to the fixed dimension. The second magnet is positioned in the fixed sensor housing, utilizing the stationary space dimension. This dimensional redistribution allows the movable component to have reduced volume requirements while still enabling long path measurement capability.
3Measurement precision
If conventional magnetic sensor assembly is used, then measurement function is achieved, but cost increases due to large magnets
Solution Approach 1:
Segmenting the magnetic field generation between movable and fixed magnets allows both magnets to be optimized for smaller sizes. This reduces the cost of magnet materials and manufacturing, while still achieving the required path measurement function through their cooperative magnetic field interaction.
Solution Approach 2:
The fixed second magnet in the sensor housing provides a stationary magnetic field component that enables the movable first magnet to generate the necessary magnetic field changes during movement. This self-service arrangement eliminates the need for expensive large magnets on the movable component, reducing overall manufacturing cost while maintaining measurement precision.
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 enables precise measurement of long paths or angles with reduced space and cost, using smaller magnets, and maintains a constant output signal by aligning the auxiliary magnet to maintain the last measured magnetic field direction after the active magnet leaves the measuring region.
Implementation Method 1
spatial components of a magnetic field of a magnet system on the moved component change in their direction over the path that is to be ascertained
Implementation Method 2
Hall sensors, in particular so-called 2D or 3D Hall sensors
Implementation Method 3
xMR sensors, such as for example AMR or GMR sensors
Data Source
AI summary
A sensor assembly for ascertaining the path of a moved part includes a magnetic measuring assembly and a fixed sensitive measure element. The magnetic measuring assembly has a magnetic field with at least one spatial component that is changed by the movement of the part along the path to be ascertained. The position of the moved part is detected in relation to the fixed sensitive measuring element. The magnetic field is generated by at least one effective magnet connected to the moved part, and at least one support magnet arranged in a fixed manner in the measuring region of the sensitive measuring element.