Motor Rotor Magnet Sheet Structure for Expansion and Adhesion
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Solution Overview
Problem
Conventional rotor designs for electric motors face challenges in balancing the expandability and adhesion of the insulating sheet used to fix magnets within the rotor core, where increased expandability leads to higher porosity and reduced adhesion, making it difficult to securely fix magnets, especially in through holes.
Innovation Solution
A rotor design incorporating a sheet with a first contact layer, a second contact layer, and a body layer, where the body layer has a higher porosity than the contact layers, allowing for increased expandability while the contact layers with lower porosity enhance adhesion to the rotor core and magnet surfaces, using materials like glass fibers and resin, and expanding the sheet through heat or chemical reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the sheet expands more to fill the space between the inner surface of the hole and the side surface of the magnet, then the expandability is improved, but the porosity of the expanded sheet increases, decreasing adhesion of the sheet to the inner surface of the hole and the side surface of the magnet
Solution Approach 1:
The sheet is divided into multiple layers with different porosity characteristics. The first sheet (with lower porosity) provides strong adhesion to contact surfaces, while the second sheet (with higher porosity) provides excellent expandability to fill gaps, resolving the contradiction between adhesion and expandability
Solution Approach 2:
Different regions of the sheet structure have different properties: the first sheet has low porosity for high adhesion at contact points, while the second sheet has high porosity for maximum expansion in the gap-filling region, allowing each part to optimize its function locally
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 design effectively improves both the expandability and adhesion of the sheet, ensuring the magnet is firmly fixed within the rotor core, reducing the likelihood of magnet displacement and enhancing cooling efficiency by allowing oil circulation through the porous body layer.
Implementation Method 1
The sheet is constituted of a burnable material and expands its volume when heated after having been inserted along with the magnet into the hole of the rotor core
Implementation Method 2
the body layer including a porous structure and disposed between the first contact layer and the second contact layer
Data Source
AI summary
A rotor for an electric motor may include a rotor core having a hole; a magnet inserted in the hole; and a sheet disposed between an inner surface of the hole and a side surface of the magnet, wherein the side surface faces the inner surface. The sheet may include a first contact layer contacting the inner surface of the hole; a second contact layer contacting the side surface of the magnet; and a body layer including a porous structure and disposed between the first contact layer and the second contact layer. The body layer may have a higher porosity than at least one of the first contact layer and the second contact layer.