Angular Sector Magnet for Precision Position Sensing
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Solution Overview
Problem
Existing magnetic angular position sensor systems face challenges in accuracy due to complex magnetization requirements and the presence of ferromagnetic parts, making them difficult to produce and integrate in constrained spaces with limited volume.
Innovation Solution
A method using a magnetized body in the form of an angular sector with a magnetization vector parallel to a fixed magnetization plane, allowing for a simpler production process and improved accuracy by using a network of parallel electrical conductors to generate a magnetizing magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetized body with complex variable direction magnetization is used to achieve accurate angular position measurement, then measurement precision is improved, but manufacturing complexity increases significantly
Solution Approach 1:
The patent changes the magnetization parameters from complex variable direction to simpler configurations. Specifically, it uses radially directed magnetization or alternating north-south polarity patterns that can be achieved with standard magnetization equipment, while still producing accurate angular position measurements through the magnetic field variations detected by the measurement cell
Solution Approach 2:
The patent employs inexpensive ferrite permanent magnets with simplified magnetization patterns instead of expensive rare-earth magnets requiring complex magnetization. The simplified magnetization structure allows use of lower-cost materials and equipment while maintaining measurement functionality
2Strength
If high current is used to generate strong magnetizing magnetic field, then magnetization strength is improved, but energy consumption and cost increase
Solution Approach 1:
The patent applies preliminary magnetization to the permanent magnet during the manufacturing process using optimized magnetization circuits and pole piece arrangements. This preliminary action creates sufficient residual magnetization that does not require high continuous current during operation, reducing energy consumption while maintaining measurement accuracy
Solution Approach 2:
The patent replaces the need for continuous high-current electromagnetic fields with a permanently magnetized structure that generates the required magnetic field passively. This substitution eliminates ongoing energy consumption while maintaining the magnetic field strength needed for accurate measurement
3Measurement precision
If complex magnetization geometry is implemented to achieve variable direction magnetization, then measurement accuracy is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent segments the magnetized body into discrete regions with uniform magnetization polarity (north and south poles). This segmentation allows each region to be magnetized independently using simple, uniform magnetic fields during manufacturing, avoiding the need for complex continuous variable direction magnetization while still creating the necessary magnetic field patterns for accurate measurement
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 approach enables the determination of relative angular position with enhanced precision and ease of production, optimizing the magnetization angle and reducing the need for high current and expensive electronics.
Implementation Method 1
circulation of an electric current in the bundles of electrical conductors, the direction of circulation of the current... forming one or more outward bundles in which the current circulates according to a first direction... the current circulating in the bundles being able to generate, around the network and in the body of magnetizable material, a magnetizing magnetic field
Implementation Method 2
a magnetized body in the form of an angular sector... having a magnetization whose magnetization vector... has a continuously variable direction in the magnetization plane as a function of the position of the point of the magnetized body
Implementation Method 3
at least a first measurement cell at a first measurement point, delivering two electrical signals respectively representative of a primary component and a secondary component of the magnetic field created by the magnetic body at the measurement point of the cell considered
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
The invention relates to a method for determining a relative angular position between two parts about an axis of rotation (A) using a magnetised body (10) in the form of an angular sector curved about the axis of rotation (A), characterised in that the magnetisation plane (PM) of the magnetised body is parallel to the axis of rotation (A). The invention relates to a sensor system comprising such a magnetised body and to a method for producing such a magnetised body.