Rotor Magnet Housing Gap Structure for Direct Magnet Cooling
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Solution Overview
Problem
The existing manufacturing methods for magnet-embedded motors do not effectively enhance the cooling performance of magnets within the rotor, as the magnet housing holes are completely filled with plastic, preventing direct cooling by cooling mediums.
Innovation Solution
The method involves manufacturing rotor magnet housing holes with an elongated portion that creates a gap between the inner surfaces of the hole and the magnet, allowing for the injection of thermoplastic to fix the magnet while maintaining a gap for cooling medium passage, with the gap dimension being less than or equal to 0.45 mm to prevent plastic flow into it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnet housing holes are completely filled with plastic to fix magnets, then manufacturing precision and reliability are improved, but cooling performance deteriorates because magnets cannot be directly cooled by cooling medium
Solution Approach 1:
The magnet housing hole is designed with non-uniform cross-section, having a larger opening at one end and a smaller opening at the other end. This local variation in geometry allows different regions to serve different functions: the smaller opening region provides adequate plastic filling for reliable magnet fixation, while the larger opening region creates space for cooling medium to contact and cool the magnet directly, thus resolving the contradiction between fixing reliability and cooling performance
Solution Approach 2:
The magnet housing hole is segmented into functional zones along its length - a first region for magnet accommodation and plastic filling, and a second region with larger cross-section for cooling medium passage. This segmentation allows the single hole structure to simultaneously achieve both secure magnet fixation and effective cooling, addressing the technical contradiction
2Ease of manufacture
If magnet housing holes are completely filled with plastic, then manufacturing simplicity is maintained, but thermal management capability deteriorates
Solution Approach 1:
The magnet housing hole features local quality variation with different cross-sectional areas at different positions. This design maintains manufacturing simplicity by using a single-hole structure that can be formed by conventional methods, while the local geometric variation naturally creates cooling passages without requiring additional complex manufacturing steps, thus resolving the contradiction between ease of manufacture and thermal management capability
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 configuration improves the cooling performance of the magnets by allowing direct cooling with a medium, such as cooling oil, through the non-filled regions, enhancing the rotor's thermal management.
Implementation Method 1
injecting thermoplastic into each of magnet housing holes in a core with a magnet accommodated in each magnet housing hole, thereby fixing the magnets
Data Source
AI summary
A method for manufacturing a rotor includes preparing magnets and a core including magnet housing holes. Each magnet housing holes including an elongated hole portion. The elongated hole portion and the magnet are configured such that a difference between a dimension in a width direction of the elongated hole portion and a dimension in the width direction of the magnet when accommodated in the elongated hole portion is greater than 0 and less than or equal to 0.45 mm. The method further includes accommodating the magnets in the elongated hole portions of the magnet housing holes, clamping the core between a first die and a second die in a state in which the magnets are accommodated in the elongated hole portions of the magnet housing holes, and injecting the thermoplastic into the magnet housing holes of the core clamped between the first die and the second die.