Hollow Core Magnetic Position Sensor Shielding
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Solution Overview
Problem
Conventional position measurement systems are sensitive to ferrous materials and spurious magnetic fields, leading to distorted magnetic fields and nonlinear output signals due to external interference.
Innovation Solution
A hollow sensor body with a movable magnet inside, coupled with a signal transceiver that generates and receives signals to determine the magnet's position based on impedance discontinuities, and uses magnetic shielding to isolate internal magnetic fields from external interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the magnet is positioned external to the waveguide sensor, then the position measurement system can operate with a simple structure, but the system becomes sensitive to ferrous materials and spurious magnetic fields causing distorted magnetic fields and nonlinear output signals
Solution Approach 1:
The magnet is nested within the hollow sensor body, creating a protected internal environment. This nesting arrangement allows the magnetic field to be contained and controlled within the sensor body, preventing external ferrous materials and spurious magnetic fields from distorting the field while maintaining a relatively simple overall structure.
2Measurement precision
If ferrous material is present in the vicinity of the position measurement system, then the system can detect position, but the magnetic field becomes distorted and the output signals become nonlinear
Solution Approach 1:
The hollow sensor body structure converts the potentially harmful effect of external magnetic fields into a beneficial contained environment. By enclosing the magnet within the hollow body, the system uses the structural enclosure to shield the magnetic field from external interference, thereby eliminating distortion and nonlinearity caused by nearby ferrous materials.
3Ease of operation
If the magnet is moved relative to the hollow sensor body, then position measurement can be performed, but external magnetic fields can affect the permeability and inductance of the waveguide sensor
Solution Approach 1:
The hollow sensor body acts as an intermediary structure between the magnet and the external environment. This intermediate enclosure protects the magnetic field from external magnetic fields, preventing changes in permeability and inductance that would occur if the magnet were exposed to external interference during movement.
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 design reduces distortion and nonlinearities by containing the magnetic field within the hollow sensor body, allowing for accurate position measurement and immunity to external magnetic fields.
Implementation Method 1
The magnet creates an impedance discontinuity in a region of the waveguide sensor proximate to the magnet. A reflection of the pulse is reflected from the point of impedance discontinuity
Implementation Method 2
A reflection of the pulse is reflected from the point of impedance discontinuity, resulting in a reflected pulse
Implementation Method 3
the magnet is configured to generate a magnetic field sufficient to locally saturate a magnetic material associated with the hollow sensor body, the magnetic material configured to cause an impedance discontinuity
Data Source
AI summary
A position sensing system is disclosed. The position sensing system may include a hollow sensor body. A magnet may be disposed in the hollow sensor body. The magnet may be movable within the hollow sensor body.