Segmented Non-Magnetic Covers for Motor Magnet Fixation
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Solution Overview
Problem
Conventional magnet structures face issues such as magnet falling due to centrifugal force, corrosion, and insufficient reduction of eddy currents, which affect the reliability and efficiency of motor performance.
Innovation Solution
A magnet structure featuring permanent magnets fixed on a baseplate with a cover structure made of non-magnetic material, where the covers are positioned to create gaps that reduce eddy currents, absorb thermal expansion stress, and prevent corrosion, while the baseplate can be made of magnetic material to enhance magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single cover structure is used to cover all magnets, then the structure is simple, but eddy currents are not sufficiently reduced
Solution Approach 1:
The single cover structure is divided into multiple separate covers, each covering individual magnets or groups of magnets. This segmentation interrupts the continuous conductive path that would otherwise allow large eddy currents to flow across the entire cover surface, thereby reducing energy losses while maintaining structural simplicity
2Device complexity
If magnets are bonded in an exposed state on the rotor surface, then the structure is simple, but magnets fall due to centrifugal force and corrosion occurs
Solution Approach 1:
Thin cover structures are used to encapsulate and protect the magnets. These covers act as protective shells that prevent magnets from falling due to centrifugal force while also providing corrosion protection, without significantly increasing the overall device complexity
3Temperature
If the baseplate is expanded or contracted by heat, then thermal expansion occurs, but permanent magnets may fracture or crack
Solution Approach 1:
The baseplate is divided into multiple segmented sections with gaps between them. These gaps act as expansion joints that accommodate thermal expansion and contraction of the baseplate, preventing stress concentration that would otherwise lead to magnet fracturing or cracking
4Reliability
If the number of covers is increased to match the number of permanent magnets, then protection is improved, but the number of components increases and productivity decreases
Solution Approach 1:
Multiple covers are designed to span across and cover multiple magnets simultaneously. This merging approach maintains comprehensive protection for all magnets while reducing the total number of cover components, thereby improving assembly efficiency and productivity
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 effectively fixes permanent magnets, reduces eddy currents, enhances magnetic force, and improves the motor's output and durability by preventing corrosion and fracturing, while maintaining a simpler and stronger baseplate design.
Implementation Method 1
As the covers are divided by the gap between the covers, eddy currents can be reduced at the covers to increase output of a motor
Implementation Method 2
When the baseplate (e.g., iron) is expanded or contracted by heat, the gap between the permanent magnets can absorb stress applied to the permanent magnets
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
Provided is a magnet structure (MS) which includes a plurality of permanent magnets (2) fixed onto a baseplate (1), and a cover structure (3) for covering the plurality of permanent magnets (2). The cover structure (3) includes a plurality of covers (3a) that is formed of a non-magnetic material and covers the plurality of permanent magnets (2). A relative position between the plurality of covers (3a) is fixed, and there is a gap (G) between the neighboring covers (3a).