Permanent Magnet Rotor Core Structure for Damage-Free Insertion
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Solution Overview
Problem
Conventional permanent magnet-type rotary electric machines face issues such as damage to permanent magnets during insertion, peeling of anti-rust coatings, rotor core damage, and increased stress due to centrifugal forces, leading to demagnetization and reduced rotor strength.
Innovation Solution
The rotor core is composed of laminated first and second rotor cores with magnet insertion holes featuring flux barriers and gaps, guide portions, and recessed openings, allowing easy magnet insertion and resin filling to secure the magnets without excessive stress, enhancing rotor strength and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the permanent magnet is press-fitted into the magnet insertion hole to eliminate gaps, then the magnet is securely held in place, but the permanent magnet suffers damage such as cracking and chipping during insertion
Solution Approach 1:
The patent introduces a gap between the permanent magnet and the magnet insertion hole, and fills this gap with resin before the magnet is fully inserted. This resin acts as a cushioning material that absorbs insertion stress and prevents direct contact between the magnet and the hole walls, thereby preventing cracking and chipping during the insertion process while still securing the magnet in place.
2Reliability
If the permanent magnet is press-fitted into the rotor core, then the magnet is securely mounted, but excessive stress is applied to the rotor core causing damage
Solution Approach 1:
The patent introduces resin as an intermediary material between the permanent magnet and the rotor core. The resin fills the gap and provides a compliant mounting medium that secures the magnet while distributing stresses uniformly, preventing concentration of forces that would damage the rotor core laminations.
3Manufacturing precision
If the magnet insertion hole and magnet have a V-shaped configuration, then the magnet positioning is improved, but the guide portions experience increased stress from centrifugal force during rotation
Solution Approach 1:
The resin filling the gap between the magnet and the V-shaped magnet insertion hole acts as a cushioning material that reduces the stress transmitted to the guide portions during rotor rotation. This allows the V-shaped configuration to maintain its positioning function while the resin absorbs the centrifugal forces, preventing excessive stress on the guide portions.
4Reliability
If the permanent magnet is coated with anti-rust coating, then corrosion protection is provided, but the coating peels off and causes rust, and insertion into the magnet insertion hole becomes difficult
Solution Approach 1:
The resin introduced into the gap between the magnet and the magnet insertion hole serves as an intermediary that facilitates insertion. The resin's compliant nature allows it to accommodate the magnet during insertion without requiring excessive force, while still providing a protective environment that complements the anti-rust coating's corrosion protection function.
Data Source
AI summary
The distance formed between surfaces facing in the thickness direction of the permanent magnet is set to be larger than the thickness of the permanent magnet, whereby gaps are formed between the permanent magnet and the magnet insertion holes. The magnet insertion hole of the first rotor core has formed therein a guide portion for positioning the permanent magnet. The magnet insertion hole of the second rotor core has formed therein an opening portion that connects the gap and the flux barrier to each other. The first rotor core and the second rotor core are laminated together in a mixed manner in the axis direction.