Segmented Permanent-Magnetic Rotor for Electric Motors
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Solution Overview
Problem
Existing permanent-magnetic rotors for electric motors, particularly internal rotor motors, face challenges in achieving optimal effectiveness and stability due to the presence of short-circuit crosspieces that reduce magnetic flow efficiency and complicate the structure, leading to either reduced effectiveness or limited stability.
Innovation Solution
A permanent-magnetic rotor design featuring a sheet-metal package composed of two types of rotor sheets: holder sheets with connection crosspieces for stability and intermediate sheets without crosspieces, allowing for reduced short-circuit flow and improved magnet utilization, while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If short-circuit crosspieces are provided in all rotor sheets to ensure structural stability, then the rotor stability is improved, but the magnetic flow efficiency deteriorates due to short-circuiting of magnetic flux
Solution Approach 1:
The rotor is divided into different sheet types: holder sheets with connection crosspieces for stability and intermediate sheets without crosspieces for magnetic efficiency. This segmentation allows different functional requirements to be met in different parts of the rotor structure.
Solution Approach 2:
Connection crosspieces are provided only in holder sheets at specific locations where structural stability is needed, rather than uniformly in all rotor sheets. This local application of crosspieces minimizes magnetic short-circuiting while maintaining necessary structural support.
2Loss of energy
If the rotor structure is simplified by removing short-circuit crosspieces to improve magnetic flow, then the magnetic flow efficiency is improved, but the rotor stability deteriorates
Solution Approach 1:
The rotor sheets are segmented into holder sheets and intermediate sheets with different structural characteristics. Holder sheets provide stability through connection crosspieces, while intermediate sheets allow unrestricted magnetic flow without crosspieces.
Solution Approach 2:
Holder sheets act as intermediary structural elements that provide mechanical support and stability without requiring crosspieces in every sheet. These holder sheets mediate between the need for structural integrity and magnetic flow efficiency.
3Ease of manufacture
If uniform rotor sheet design with connection crosspieces is used to ensure stability, then the manufacturing process is simplified, but the permanent magnet utilization deteriorates due to magnetic short-circuiting
Solution Approach 1:
The rotor manufacturing process is segmented into producing different sheet types (holder sheets and intermediate sheets). This allows standardized production of each sheet type while optimizing the overall magnet utilization by alternating between sheets with and without crosspieces.
Solution Approach 2:
Connection crosspieces are applied locally only in holder sheets rather than uniformly across all sheets. This local differentiation maintains ease of manufacture through standardized components while improving permanent magnet utilization by reducing unnecessary magnetic short-circuiting in intermediate sheets.
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 the effectiveness of the motor by optimizing the use of permanent magnets and improving stability without the need for complex connections, resulting in a simple, cost-effective, and stable rotor structure.
Implementation Method 1
permanent magnets are disposed in accommodation pockets formed by recesses of the rotor sheets
Implementation Method 2
connection crosspieces or crosspiece sections... which connect the pole-shoe sections with one another, on the one hand, as well as with the central yoke sheet section
Data Source
AI summary
A permanent magnetic rotor for an electric motor, preferably for an internal rotor motor, includes a laminated core consisting of several rotor sheets that are stacked in the axial direction. Permanent magnets are arranged in receiving pockets formed by recesses of the rotor sheets, the laminated core being composed of at least two differently shaped types of rotor sheets. Several rotor sheets of a first type of rotor sheet are provided as retaining sheets that respectively include a central yoke lamination section that is connected or can be connected to the rotor shaft and respectively one or more external pole shoe sections that are connected to the yoke lamination section by one or more connecting bars or bar sections, and several rotor sheets of a second type of rotor sheet are provided as intermediate sheets without connecting bars.