C-Shaped Magnet Segments for Magnetic Circuit Assembly
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Solution Overview
Problem
The manufacturing of cylindrical rare earth sintered magnets for magnetic circuits is challenging due to deformation, cracking, and high sintering costs, which affects the precision and miniaturization of actuators and speakers, and requires complex magnetization processes.
Innovation Solution
The use of C-shaped permanent magnet segments, which are easier to manufacture and magnetize, are magnetically attracted to a cylindrical yoke member with a collar, eliminating the need for adhesives and simplifying the assembly process by using a center rod for positioning and fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cylindrical rare earth sintered magnets are manufactured using powder metallurgy method, then high magnetic intensity is achieved, but the compacted body shrinks and deforms during sintering treatment requiring polishing and increasing manufacturing cost
Solution Approach 1:
The patent divides the cylindrical permanent magnet into multiple C-shaped magnet segments that are assembled together. Each segment is manufactured separately with easier dimensional control, avoiding the shrinkage and deformation problems of large cylindrical magnets. The segments are then assembled using a magnet holder to form the complete cylindrical magnet structure.
2Quantity of substance
If the shape of the magnet is made cylindrical, then the volume relative to weight becomes large, but the number of magnets to be treated at a time decreases increasing sintering cost
Solution Approach 1:
By segmenting the magnet into multiple C-shaped pieces, the patent enables parallel processing of multiple segments during sintering. This increases the number of magnets treated simultaneously, reducing overall sintering costs while maintaining the required magnetic properties.
3Manufacturing precision
If dimensional accuracy in outside and inside diameters of cylindrical rare earth sintered magnet is low, then the area of magnet in contact with yoke becomes very small, but the force of affixing the magnet to yoke is considerably diminished
Solution Approach 1:
The C-shaped magnet segments provide larger contact areas with the yoke compared to a single cylindrical magnet with low dimensional accuracy. The segmented structure allows for better distribution of contact forces and improved affixing strength.
Solution Approach 2:
The patent introduces a magnet holder as an intermediary component that secures the C-shaped magnet segments to the yoke. This magnet holder ensures reliable affixing even when dimensional accuracy of the magnets themselves is not high.
4Shape
If a cylindrical permanent magnet is used in a magnetic circuit, then radial orientation is achieved, but the magnet sustains cracks or chips during sintering resulting in greatly lowered yield
Solution Approach 1:
By dividing the magnet into multiple smaller C-shaped segments, the patent reduces the size of each individual magnet during sintering. This smaller size reduces internal stresses and the likelihood of cracks and chips during the sintering process, significantly improving yield.
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 production of high-performance, miniaturized magnetic circuits with improved yield and reduced manufacturing costs, enhancing the reliability and efficiency of actuators and speakers.
Implementation Method 1
a plurality of permanent magnet segments of a partially circular arc in cross section having respective outer surfaces attracted magnetically to the inner circumferential surface of the cylindrical yoke member and respective one end faces attracted magnetically to the collar of the cylindrical yoke member
Data Source
AI summary
A magnetic circuit is made by magnetically attracting a permanent magnet segment of a partially circular arc in cross section to an outer peripheral surface of a center rod, causing the magnet segment in a magnetically attracted state to face a yoke member, using a nonmagnetic supporter to regulate the magnet segment in position, extracting the center rod from the magnet segment in a position-regulated state, and magnetically attracting and fixing the magnet segment to the yoke member.