Flux-Concentrating Rotor with Segmented Sheets for Centrifugal Force Management
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Solution Overview
Problem
Existing electrical machines face limitations in achieving higher power density due to the distribution of magnetic fields and the management of centrifugal forces within their structure.
Innovation Solution
The electrical machine design includes a rotor with both central and outer regions featuring permanent magnets, where magnetic fields are directed parallel to the axis of rotation, and form-fitting elements transfer centrifugal forces from the central to the outer regions, using smaller sheets in the outer regions surrounded by a holding device and elastic intermediate layers to optimize force distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If permanent magnets are arranged in both central and outer regions of the rotor, then power density is improved, but centrifugal forces acting on the sheets increase
Solution Approach 1:
The rotor is divided into a central region and outer regions, with permanent magnets arranged in both areas. The sheets are segmented into different sizes corresponding to these regions, allowing differential management of centrifugal forces while maintaining high power density throughout the rotor structure.
Solution Approach 2:
Different regions of the rotor are given different properties: the central region has larger sheets to handle higher centrifugal forces, while the outer regions have smaller sheets. This local differentiation allows the structure to optimize both power density and force management in each specific area.
2Strength
If sheets in outer regions are made smaller, then structural integrity under centrifugal force is improved, but magnetic flux concentration is reduced
Solution Approach 1:
The magnetic flux is directed parallel to the axis of rotation rather than radially outward. This dimensional change in flux direction allows the smaller outer sheets to effectively concentrate magnetic flux along the axial direction, maintaining power density while accommodating the structural constraints of smaller sheet size in outer regions.
3Force
If form-fitting elements are used to transfer centrifugal forces, then force distribution is improved, but device complexity increases
Solution Approach 1:
Form-fitting elements act as intermediaries between the permanent magnets and the sheets, transferring centrifugal forces from the central region to the outer regions. These elements provide a mechanical coupling that distributes forces evenly throughout the rotor structure without requiring complex external reinforcement systems.
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 enhances power density by concentrating magnetic flux and minimizing the air gap between the rotor and stator, while ensuring even force distribution and structural integrity through innovative use of form-fitting elements and elastic layers.
Implementation Method 1
centrifugal forces acting on the sheets arranged in the central region of the rotor are transferred into the sheets arranged in the outer regions of the rotor
Implementation Method 2
a first elastic intermediate layer is arranged between the rods and the sheets. In order to achieve as even a force distribution as possible
Implementation Method 3
the magnetic fields coming from the permanent magnets are directed radially toward the stator viewed in respect of the axis of rotation
Data Source
AI summary
A rotor having a number of tangentially magnetized permanent magnets tangentially evenly distributed and arranged both in the center region and in the outer regions in the axial direction is disclosed. Flux-guiding elements between the permanent magnets guide the magnetic fields of the permanent magnets radially toward the center region of the stator. The flux-guiding elements comprise a plurality of sheets stacked on one another in the axial direction. The sheets in the outer regions are smaller than the sheets in the center region. The sheets arranged in the outer regions are surrounded on their radially outside end by a retaining apparatus. Form-fitting elements transmit centrifugal forces acting on the sheets arranged in the center region are transmitted to the sheets arranged in the outer regions.