Magnetized Piston Rod With Linear Radial Field Gradient
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Solution Overview
Problem
Existing position measurement methods for moving machine parts, such as those using potentiometers, inductive sensors, or incremental encoders, are not sufficiently reliable due to complexity in magnetic coding, especially for applications like piston rods.
Innovation Solution
A magnetized rod with a non-zero, constant gradient radial magnetic field component along its axial direction, allowing for a simple linear relationship between the magnetic field and position, and a position measurement device comprising this rod and magnetic field sensors to detect the radial component for accurate axial position measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If incremental encoders with periodic material measure are used for magnetic position measurement, then position measurement capability is achieved, but the magnetic coding of the piston rod becomes complex
Solution Approach 1:
The patent changes the magnetic field parameter distribution along the rod axis to create a linear gradient of the radial magnetic field component. This simple linear parameter variation replaces complex periodic magnetic coding patterns, achieving position measurement through the linear relationship between radial field strength and axial position while significantly reducing coding complexity
Solution Approach 2:
The patent creates a specific local magnetic field quality along the rod axis where the radial component has a constant non-zero gradient. This localized linear gradient region provides a simplified measurement zone that eliminates the need for complex periodic coding structures while maintaining measurement precision
2Measurement precision
If conventional position measurement methods (potentiometers, inductive sensors) are used, then position measurement is achieved, but reliability is insufficient
Solution Approach 1:
The patent replaces mechanical measurement systems (potentiometers, inductive sensors) with a magnetic field-based measurement system. The magnetized rod with its linear radial field gradient provides a non-contact, wear-free measurement method that is inherently more reliable than mechanical or traditional inductive systems while maintaining measurement precision
3Ease of operation
If a linear relationship between radial magnetic field component and axial position is achieved, then measurement simplicity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary magnetization treatment to the rod during or after manufacturing to establish the linear radial magnetic field gradient. By pre-establishing the required magnetic field distribution through controlled magnetization processes, the system achieves measurement simplicity without requiring complex manufacturing of the rod structure itself
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 provides a reliable and straightforward method for position measurement, reducing interference from external fields and enabling precise axial position determination with a linear correlation between the radial magnetic field component and position, enhancing the reliability of position measurement devices.
Implementation Method 1
a radial component of the magnetic field of the rod having a non-zero, constant gradient within an axial region of the rod as a function of the axial position
Implementation Method 2
at least one magnetic field sensor for outputting a signal dependent on the radial magnetic field component
Data Source
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AI summary
The magnetized rod according to the invention has a magnetic field measurable outside the rod, wherein a radial component of the magnetic field of the rod within an axial region of the rod has a non-zero gradient, in particular a constant gradient, depending on the axial position. Furthermore, the invention relates to a device for position measurement using the magnetized rod according to the invention and to a method for magnetizing a magnetizable and electrically conductive rod.