Segmented Rotor Magnet Fixation for Precise Balance and Cooling
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Solution Overview
Problem
Existing methods for fixing permanent magnets in rotor laminations of electrical machines face challenges in achieving precise alignment and balancing, particularly in high-speed applications, due to manufacturing tolerances and imbalances, which can lead to operational issues over the machine's service life.
Innovation Solution
The use of resin transfer molding with two distinct polymer compositions, one containing magnetic filler particles and the other electrically conductive filler particles, allows for selective magnet fixation and optimal adjustment of physical properties, such as heat dissipation and magnetic holding force, by segregating areas within the rotor pocket to prevent mixing and ensure precise magnet positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single homogeneous material is used for magnetic fixation of permanent magnets, then the manufacturing process is simple, but the precision of magnet alignment and balancing is insufficient
Solution Approach 1:
The patent applies local quality by dividing the magnetic pocket into different regions (first region and second region) and filling each region with a different polymer composition. The first region contains a first polymer composition with specific properties, while the second region contains a second polymer composition with different properties. This allows optimization of magnet alignment precision in specific areas without complicating the entire fixation structure.
Solution Approach 2:
The patent segments the magnetic pocket into multiple regions that can be independently filled with different materials. The magnetic pocket is divided into a first region and a second region, allowing separate injection molding of different polymer compositions into different areas, thereby achieving precise magnet positioning while maintaining a relatively simple overall structure.
2Ease of manufacture
If large manufacturing tolerances are used for economical production, then production cost is reduced, but rotor imbalance increases
Solution Approach 1:
The patent changes the physical and chemical parameters of the polymer compositions used for fixation. By selecting polymer compositions with different viscosities, curing characteristics, and mechanical properties, the system can accommodate manufacturing tolerances in magnet placement while still achieving adequate fixation strength and rotor balance, thus maintaining production economy without sacrificing reliability.
3Temperature
If electrically conductive particles are used in the polymer composition, then heat dissipation is improved, but eddy currents may form
Solution Approach 1:
The patent applies local quality by using electrically conductive particles only in the first polymer composition filled in the first region of the magnetic pocket, while the second polymer composition in the second region uses non-conductive particles. This localized approach enables heat dissipation in areas where it is most needed while avoiding eddy current formation in other regions, thus resolving the contradiction between heat dissipation and eddy current prevention.
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 approach enables precise alignment and long-term operational stability of permanent magnets within rotor pockets, reducing imbalances and enhancing heat dissipation, thus improving the overall performance and reliability of electrical machines.
Implementation Method 1
the first polymer composition in the first region comprises magnetic filler particles
Implementation Method 2
the second polymer composition in the second region comprises electrically conductive filler particles of suitable size to avoid the formation of eddy currents
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a rotor 1 for an electric machine comprising a magnetic pocket 20 and within the magnetic pocket 20 a permanent magnet 10, a first polymer composition comprising magnetic filler particles in a first region 22 and a second polymer composition comprising electrically conductive filler particles that do not cause eddy currents in a second region 24, as well as a method for manufacturing such a rotor 1 and a gating system for carrying out the method.