Rotor Slit Design for Simplified Magnetization Process
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Solution Overview
Problem
In motor systems with permanent magnet embedded rotors, the magnetization process requires strong forces to hold the rotor in place due to attractive and repulsive forces generated during magnetization, complicating the magnetization process and increasing the need for robust holding mechanisms.
Innovation Solution
The rotor design includes a slit on the outer side of the magnet insertion hole in the radial direction, allowing for parallel alignment of magnetization flux and easy magnetization directions during rotation, reducing the force required to hold the rotor and simplifying the magnetization process by minimizing the magnetization flux through already-magnetized parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the rotor is magnetized by rotating it to a different rotational position for uniform magnetization, then the magnetization uniformity is improved, but the force required to hold the shaft increases due to attractive and repulsive forces between the magnetized part and magnetization flux
Solution Approach 1:
The rotor core is divided into two independent rotors (first rotor and second rotor) that can rotate in opposite directions. This segmentation allows each rotor to be magnetized independently, reducing the interaction forces between magnetized parts and magnetization flux, thereby reducing the holding force requirement while maintaining magnetization uniformity.
Solution Approach 2:
Instead of rotating a single rotor in one direction, the invention rotates two rotors in opposite directions simultaneously. This inversion of the rotation approach ensures that the magnetization flux interacts with unmagnetized or oppositely magnetized parts, minimizing attractive and repulsive forces on the shaft during magnetization.
2Stability of the object's composition
If a strong holding force is applied to the shaft during magnetization, then the rotor stability is improved, but the magnetization process becomes more complex and requires stronger jigs
Solution Approach 1:
The magnetization process is segmented into two independent operations on two separate rotors. Each rotor undergoes magnetization independently, allowing for simpler holding mechanisms and reducing the overall complexity of the magnetization process while maintaining rotor stability through controlled rotation.
Solution Approach 2:
The invention introduces dynamic rotation of the rotors during magnetization instead of static holding. By rotating the rotors in opposite directions, the system dynamically manages the magnetic forces, reducing the need for strong static holding forces and simplifying the magnetization equipment requirements.
3Strength
If the rotor is designed without a slit on the outer side of the magnet insertion hole, then the structural integrity is improved, but the magnetization flux cannot be effectively reduced and the force required to hold the shaft remains high
Solution Approach 1:
A slit is introduced on the outer side of the magnet insertion hole, segmenting the magnetic path. This slit allows the magnetic flux to be redirected and reduced, thereby lowering the interaction forces between the magnetized parts and magnetization flux while maintaining sufficient structural integrity of the rotor core.
Solution Approach 2:
The slit extracts or removes a portion of the magnetic flux path that would otherwise contribute to high interaction forces. By taking out this flux path through the slit, the force required to hold the shaft during magnetization is reduced while the rotor maintains its structural integrity.
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 reduces the force needed to hold the rotor, simplifies the magnetization process, enhances magnetizability, and increases output power while maintaining durability by reducing the reluctance torque and leakage magnetic flux.
Implementation Method 1
electric current is supplied to a winding of the stator or the magnetization yoke to generate magnetization flux so that the magnetic member is magnetized to become a permanent magnet
Data Source
AI summary
A rotor includes a rotor core having a magnet insertion hole and a permanent magnet provided in the magnet insertion hole. The rotor core has a slit on an outer side of the magnet insertion hole in a radial direction of the rotor core. The permanent magnet is magnetized by placing the rotor so as to face a tooth around which a winding is wound, rotating the rotor in a first rotating direction from a rotational position where a center of the magnet insertion hole in a circumferential direction of the rotor core faces a middle portion between both ends of the winding in the circumferential direction and supplying electric current to the winding, and rotating the rotor in a second rotating direction opposite to the first rotating direction from the rotational position and supplying electric current to the winding.