Linear Magnetic Position Sensor Homogeneous Field Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing linear magnetic position sensors face challenges in producing a linear magnetic field due to manufacturing tolerances and susceptibility to thermal influences, requiring complex geometries and precise positioning of permanent magnets.
Innovation Solution
The solution involves spacing permanent magnets apart and connecting them with magnetic conductor elements to form a closed magnetic circuit, creating a homogeneous magnetic field within the measuring section, which simplifies production and reduces thermal influences, while maintaining a linear magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If curved inner sides of permanent magnets are used to generate a linear magnetic field, then measurement precision is improved, but manufacturing precision deteriorates due to tolerance sensitivity
Solution Approach 1:
The magnetic field generating unit is segmented into multiple permanent magnets arranged in a specific pattern. Instead of relying on a single complex curved magnet, the patent uses multiple simpler magnets (e.g., four magnets in a rectangular arrangement) that collectively generate the linear magnetic field, reducing the impact of individual manufacturing tolerances.
Solution Approach 2:
The patent changes the geometric parameters of the permanent magnets from curved surfaces to flat surfaces with simple rectangular or square cross-sections. This parameter change simplifies manufacturing while maintaining the ability to generate a linear magnetic field through proper spatial arrangement and polarization of multiple magnets.
2Measurement precision
If complex curved geometries are used for permanent magnets, then a linear magnetic field is achieved, but device complexity increases
Solution Approach 1:
The system is divided into multiple simple permanent magnets with flat surfaces arranged in a geometric pattern. This segmentation allows each magnet to have a simple geometry while the collective arrangement produces the desired linear magnetic field, reducing overall device complexity.
Solution Approach 2:
Multiple simple permanent magnets are combined in a specific spatial arrangement to achieve the function previously requiring a single complex curved magnet. The merging of multiple simple components creates the linear magnetic field while maintaining manufacturing simplicity.
3Measurement precision
If Hall sensor is positioned close to permanent magnets for accurate measurement, then measurement precision is improved, but susceptibility to thermal influences increases
Solution Approach 1:
The patent introduces an air gap or spacing as an intermediary between the Hall sensor and permanent magnets. This spacing reduces direct thermal coupling while maintaining the magnetic field interaction necessary for measurement, thereby reducing thermal susceptibility.
Solution Approach 2:
The magnetic field distribution is optimized to provide sufficient field strength at the Hall sensor location without requiring direct contact or minimal spacing. The local magnetic field properties are enhanced through the arrangement of multiple magnets, allowing greater physical separation and reduced thermal influence.
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 results in a more accurate and cost-effective position measurement with reduced manufacturing tolerances and thermal susceptibility, enabling a stable and linear magnetic field within the measuring section.
Implementation Method 1
Linear magnetic position sensors work with a Hall sensor which, in a linear measuring section, can be displaced relative to a magnetic field which is generated by means of a permanent magnet. Along the measuring section, the magnetic field changes which is detected by the Hall sensor
Implementation Method 2
In order to be able to carry out a position measurement as exact as possible, a magnetic field as linear as possible within the measuring section is of advantage. In the case of a linear magnetic field, the magnetic field strength changes linearly, thus with a constant gradient.
Implementation Method 3
Via the two magnetic conductor elements, the two permanent magnets are connected to each other so as to form a closed magnetic circuit. The magnetic field generated by means of the magnetic field generating unit is thus located in the longitudinal direction between the permanent magnets and in the transverse direction between the magnetic conductor elements.
Data Source
AI summary
A linear magnetic position sensor may include a magnetic field generating unit having two permanent magnets for generating a magnetic field. A Hall sensor may be disposed in a region of the magnetic field forming a linear measuring section, wherein the Hall sensor and the magnetic field generating unit are linearly displaceable relative to one another along a longitudinal direction in order to position the Hall sensor within the measuring section. The permanent magnets may be polarized in a transverse direction running perpendicular to the longitudinal direction. The permanent magnets may be spaced apart from one another in the longitudinal direction. Each pole of one of the permanent magnets may be connected to a pole of the other permanent magnet via a magnetic conductor element.