Pin-Shaped Magnetic Angle Sensor With Ferromagnetic Shielding
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Solution Overview
Problem
Conventional magnetic angle sensors are not optimized for specific dimensions, particularly in pin-shaped configurations, and are susceptible to interference from external magnetic fields, limiting their application in environments with strong interfering fields.
Innovation Solution
A magnetic angle sensor unit with a ferromagnetic shielding that guides the encoder magnet's flux while preventing interfering fields from entering, using a sensor shielding around the sensor element and an encoder shielding that rotates with the encoder magnet, optimized for pin-shaped designs and multi-turn applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional magnetic angle sensors are used without optimization for specific dimensions, then they can be manufactured with standard block-shaped dimensions, but they cannot achieve the required pin-shaped configuration with long axial length and small radial extension
Solution Approach 1:
The sensor unit is segmented into distinct functional components: the sensor element housed in a sensor housing, the encoder magnet on a separate encoder unit, and ferromagnetic shielding components. This segmentation allows independent optimization of each component for its specific function while achieving the overall pin-shaped configuration.
Solution Approach 2:
Ferromagnetic shielding components are introduced as intermediary elements between the sensor element and external environment. These shielding components mediate the magnetic field interactions by guiding the encoder magnet's flux to the sensor element while blocking interfering external magnetic fields, enabling reliable operation in environments with strong interfering fields.
2Reliability
If ferromagnetic shielding is added to block interfering fields, then reliability in interfering field environments improves, but device complexity increases
Solution Approach 1:
The ferromagnetic shielding is applied locally only where needed - specifically around the sensor element and encoder magnet - rather than enclosing the entire sensor unit. This localized shielding approach provides effective protection against interfering fields while minimizing the added structural complexity.
Solution Approach 2:
The ferromagnetic shielding components serve multiple functions simultaneously: they guide the encoder magnet's magnetic flux to the sensor element, block external interfering magnetic fields, and maintain the mechanical structure of the sensor unit. This multi-functionality reduces the need for additional separate components.
3Strength
If the sensor element is completely encapsulated mechanically for protection, then mechanical protection improves, but the magnetic field path from encoder magnet to sensor element may be blocked
Solution Approach 1:
The sensor element is encapsulated in a housing that is mechanically protective but magnetically permeable. This housing acts as a flexible shell that provides mechanical strength and protection while allowing magnetic field lines to pass through freely, thus maintaining both mechanical protection and magnetic field transmission.
Solution Approach 2:
The housing and shielding components are made from ferromagnetic materials that combine mechanical strength with high magnetic permeability. This composite material approach ensures that the encapsulation provides both mechanical protection and optimal magnetic field transmission paths.
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 solution enables reliable operation in environments with strong interfering fields, such as electric motor shafts, by minimizing interference and maintaining signal precision through targeted flux guidance and shielding, allowing for precise angle measurement across multiple turns.
Implementation Method 1
the shielding shall be embodied so that it is as tight as possible against the penetration of interfering fields into the inner cavity of the shielding, so that only the use field generated by the encoder magnet impacts the sensor element
Implementation Method 2
The shielding, furthermore, comprises preferably an encoder shielding, shielding the encoder magnet on the longitudinal sides and on the backside facing away from the sensor element
Implementation Method 3
Hall-effect sensor elements are used or angle sensors operating according to the magneto-resistive principle
Implementation Method 4
rotational angle transfer between the encoder element, which is a magnet in this application and the sensor element, which is provided as an electronic chip (IC), is exclusively performed by means of magnetic field lines
Data Source
AI summary
To provide a thin and slender magnetic angle sensor, a main circuit board is disposed in the direction of the longitudinal axis of the sensor. This sensor element in form of a chip is supported on a sensor circuit board, which is positioned transversely to the main circuit board at the forward narrow side of the main circuit board.