Magnetic Encoder Core with Bending Plate for Angle Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic encoders face challenges in achieving high magnetization accuracy for detecting absolute angles, particularly when the number of magnetic poles increases, due to difficulties in producing magnetic tracks with the required precision and minimizing magnetic flux leakage.
Innovation Solution
A magnetic encoder design featuring a core member with a bending plate portion that enhances rigidity and reduces rotational deflection, where the main track with the largest number of poles is positioned closer to the bending plate, and a sub track with fewer poles is used to calculate phase differences, allowing for higher accuracy in angle detection. The magnetization process involves alternately magnetizing N and S poles while shielding adjacent tracks to minimize flux leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of magnetic poles is increased to improve angle detection precision, then measurement precision improves, but manufacturing precision becomes more difficult to achieve
Solution Approach 1:
The magnetic encoder is divided into multiple independent magnetic tracks (main track and sub tracks), each with different numbers of pole pairs. This segmentation allows each track to be magnetized separately with appropriate shielding, making it feasible to achieve high precision even with increased pole pairs by treating each track as an independent manufacturing target.
Solution Approach 2:
Magnetic shields are pre-installed between adjacent magnetic tracks before the magnetization process. This preliminary action prevents magnetic flux leakage during magnetization, ensuring that each track can be magnetized to the required precision without interference from neighboring tracks, thus enabling high manufacturing precision for tracks with many pole pairs.
2Manufacturing precision
If magnetic shields are added to prevent flux leakage between tracks, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The magnetic shields are integrated with the core member structure itself rather than being separate components. The shields form part of the core's magnetic circuit, combining the shielding function with the core structure and reducing overall device complexity while still achieving the necessary flux isolation for high manufacturing precision.
3Measurement precision
If the main track is positioned closer to the bending plate portion to reduce rotational deflection, then measurement precision improves, but ease of manufacture decreases
Solution Approach 1:
The core member is designed with a bending plate portion that creates a localized rigid support structure. By positioning the main track (which requires highest precision) in the region with greatest rigidity (closest to the bending plate), the design applies local quality enhancement exactly where needed for angle detection accuracy, while other regions can have different structural characteristics for ease of manufacture.
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 enables the production of magnetic encoders that can detect absolute angles with improved accuracy and reduced production complexity, maintaining high precision even with increased magnetic pole pairs, by prioritizing the magnetization of the main track with the larger number of poles for higher angular accuracy.
Implementation Method 1
two or more rows of magnetic tracks arranged adjacent to each other on a magnetic member provided on the track formation surface of the core member, each track having N poles and S poles alternately magnetized thereon
Implementation Method 2
A part, of the track formation surface of the core member, which is close to the bending plate portion is formed by bending the core member and therefore has high rigidity and less rotational deflection
Data Source
AI summary
A magnetic encoder having a plurality of rows of magnetic tracks and capable of detecting an absolute angle is easily producible with higher accuracy. The magnetic encoder includes: a core member of annular shape having a bending plate portion that bends and extends from an edge of a track formation surface; and two or more rows of magnetic tracks arranged adjacent to each other on a magnetic member provided on the track formation surface, each track having N poles and S poles alternately magnetized thereon. The magnetic tracks include a main track that has a largest number of magnetic poles and is used for calculating an angle, and a sub track used for calculating a phase difference from the main track. The main track is located on a side closer to the bending plate portion than the sub track.