Lundell Rotor Magnet Retainer Axial Locking
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Solution Overview
Problem
Existing rotary electric machine rotors face issues with magnet retainer displacement due to vibrations, leading to reliability concerns and difficult assembly processes, as current solutions require strong forces to prevent displacement.
Innovation Solution
The rotor design incorporates Lundell-type cores with claw poles and magnet retainers featuring projections on their circumferential side surfaces to restrain axial movement, allowing for secure retention without the need for strong force application during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnet retainers are pressed with strong force against claw poles to prevent displacement, then reliability of fixing magnet retainers is improved, but insertion requires large force and workability deteriorates
Solution Approach 1:
The magnet retainer is divided into a body portion and protruding portions (projections) that extend axially. These projections are inserted into grooves formed on the claw poles, creating a segmented locking mechanism. This segmentation allows the magnet retainer to be secured in the axial direction through the interlocking projections and grooves, eliminating the need for strong pressing forces while maintaining reliable fixation.
Solution Approach 2:
The solution transitions from relying solely on axial pressing force to utilizing the axial dimension through protruding portions that extend into grooves. By adding this dimensional feature (protrusions extending axially into grooves), the magnet retainer achieves reliable fixation in the axial direction without requiring excessive pressing force during assembly, thus resolving the contradiction between reliability and workability.
2Ease of manufacture
If magnet retainers are permitted to have elastic force and partially pressed against claw poles, then assembly force is reduced, but displacement caused by vibration is not sufficiently prevented
Solution Approach 1:
The magnet retainer incorporates protruding portions that are inserted into grooves on the claw poles, creating a segmented interlocking structure. This segmentation provides positive mechanical engagement that prevents displacement due to vibration, while the body portion can still be assembled with moderate force. The grooves and protrusions work together to ensure reliable fixation without requiring excessive assembly force.
Solution Approach 2:
The grooves formed on the claw poles serve as intermediaries that receive and lock the protruding portions of the magnet retainers. This intermediary structure (the groove-protrusion interface) mediates between the magnet retainer and the claw pole, providing reliable anti-displacement fixation while allowing for ease of assembly. The grooves act as receptacles that guide and secure the protrusions, ensuring proper positioning and preventing vibration-induced displacement.
Data Source
AI summary
A rotor for a rotary electric machine includes a pair of Lundell-type cores, a plurality of magnets, and a magnet retainer. The pair of Lundell-type cores includes a plurality of claw poles with flange portions projecting to a circumferential direction of the rotor from an end portion on an outer diameter side of each of the claw poles. The plurality of magnets are arranged between the pair of Lundell-type cores, and are magnetized in a direction of reducing flux leakage. The magnet retainer retains each of the magnets, and has side surfaces in the circumferential direction. At least one of the side surfaces is provided with at least one projection for restraining movement of the magnet retainer in an axial direction along a rotary shaft.