Segmented Magnetic Housing for Electric Machine Shielding
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Solution Overview
Problem
Conventional electric machines with aluminum housings lack electromagnetic shielding, leading to interference and increased wall thickness due to manufacturing requirements and low material strength, while using magnetically conductive materials like steel results in eddy current and hysteresis losses.
Innovation Solution
Designing the housing from a magnetically conductive material like steel with uniformly spaced, magnetically conductive holding elements that match the stator arrangement's phase, reducing magnetic losses and allowing for a thinner design, and incorporating insulating pieces for electrical insulation and cooling medium channels to enhance cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the housing is made of magnetically conductive material like steel, then electromagnetic shielding is improved, but eddy current and hysteresis losses increase
Solution Approach 1:
The housing is divided into multiple magnetically conductive segments (first housing section, second housing section, third housing section) separated by magnetically non-conductive intermediate sections. This segmentation breaks the continuous magnetic path, preventing eddy current loops while maintaining electromagnetic shielding at each segment. The intermediate sections act as magnetic insulators that block flux propagation between segments.
Solution Approach 2:
Magnetically non-conductive intermediate sections are introduced between magnetically conductive housing segments. These intermediate sections serve as mediators that electrically and magnetically isolate the conductive segments, preventing harmful eddy currents while allowing each segment to provide local electromagnetic shielding. The intermediate sections are positioned at strategic locations where magnetic flux would otherwise create closed loops.
2Ease of manufacture
If the housing is made of aluminum, then manufacturing is easier and wall thickness can be reduced, but electromagnetic shielding is lost
Solution Approach 1:
The housing employs a composite structure combining magnetically conductive materials (steel or sheet iron) with magnetically non-conductive materials. The magnetically conductive segments provide electromagnetic shielding, while the composite nature of the housing (with intermediate non-conductive sections) allows for simplified manufacturing compared to solid steel housings. This composite approach enables easier fabrication while maintaining shielding effectiveness.
3Object-affected harmful factors
If the housing is made of magnetically conductive material, then electromagnetic compatibility is improved, but wall thickness must be increased due to manufacturing requirements and material strength
Solution Approach 1:
By segmenting the housing into multiple sections with intermediate non-conductive parts, each magnetically conductive segment can be thinner while collectively providing adequate shielding. The segmentation allows for optimized wall thickness in each section, reducing the overall housing dimensions compared to a solid thick-walled magnetically conductive housing.
Solution Approach 2:
The composite construction with alternating magnetically conductive and non-conductive sections creates a housing that achieves electromagnetic compatibility with reduced wall thickness. The non-conductive intermediate sections contribute to structural integrity while allowing the magnetically conductive segments to be thinner, as they don't need to provide continuous mechanical support over long spans.
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 solution improves electromagnetic compatibility by minimizing magnetic losses and eddy currents, reduces installation space, and enhances cooling efficiency without the need for additional cooling ducts, while maintaining mechanical integrity and thermal expansion compatibility.
Implementation Method 1
Losses due to eddy currents and magnetization reversals occur when there is contact between the stator arrangement and the magnetically conductive housing
Implementation Method 2
Losses due to eddy currents and magnetization reversals occur when there is contact between the stator arrangement and the magnetically conductive housing
Implementation Method 3
The intermediate space can be used for measures to cool the electrical machine
Implementation Method 4
a cooling medium being conducted through the intermediate spaces
Data Source
Figure 1a~1b
Figure 2~3
Figure 4~5
AI summary
The invention relates to an electric machine (1) comprising: - a stator arrangement (2), in particular a circular cylindrical one; - a housing (4) made of a magnetically conductive material, which surrounds the stator arrangement (2), such that a space (5) is formed between the housing (4) and the stator arrangement (2); - retaining elements (6) which are arranged between the stator arrangement (2) and the housing (4), wherein the retaining elements (6) are made of a magnetically conductive material and are arranged circumferentially at a distance from each other corresponding to a full electrical period of the stator arrangement (2) or a multiple thereof.