Bonded Field Magnet Press-Fitting With Softened Alignment Control
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Solution Overview
Problem
Existing methods for manufacturing field magnets using bonded magnets are costly and do not ensure accurate alignment and stability during the press-fitting process, leading to potential deformation and reduced motor performance.
Innovation Solution
A method involving the softening of a cylindrical bonded magnet after thermal curing, allowing relative posture variation during press-fitting into a coupled case with a magnetic fixing portion, which reduces production costs and ensures accurate alignment without excessive stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a bonded magnet is directly pressure-bonded into a yoke using oxidation and expansion by heating, then the manufacturing process is simplified, but the manufacturing precision and alignment accuracy deteriorate
Solution Approach 1:
The bonded magnet is pre-heated and softened before press-fitting into the yoke, allowing it to be inserted with proper alignment. After positioning, the magnet is cooled and hardened in place, ensuring both ease of insertion and high alignment accuracy.
Solution Approach 2:
The patent utilizes temperature parameter changes to control the physical state of the bonded magnet. By heating the magnet to soften it and then cooling it to harden it, the process achieves both ease of manufacturing and high precision alignment without requiring complex oxidation-expansion mechanisms.
2Ease of manufacture
If a molded body is press-fitted directly into a yoke from a cavity using springback, then the production cost is reduced, but the reliability and stability of press-fitting deteriorate
Solution Approach 1:
The patent applies thermal parameter changes by heating the bonded magnet to soften it before press-fitting, and then cooling it to harden and stabilize the magnet in place. This thermal treatment ensures reliable and stable press-fitting while maintaining cost-effectiveness, avoiding the need for expensive precision fixtures or complex springback mechanisms.
3Ease of manufacture
If thermal curing treatment is performed after placing the molded body in the yoke, then the manufacturing process is simplified, but the manufacturing precision and alignment accuracy deteriorate
Solution Approach 1:
The patent performs the opposite sequence: preliminary heating and softening of the bonded magnet before insertion, followed by positioning in the yoke, and then final cooling and hardening. This reversed thermal treatment sequence ensures that alignment is established before the magnet hardens, achieving both process simplicity and high alignment accuracy.
4Ease of manufacture
If the bonded magnet is softened by reheating for press-fitting, then the ease of manufacture improves, but the strength and rigidity temporarily deteriorate
Solution Approach 1:
The patent dynamically adjusts the physical state of the bonded magnet by controlling temperature during the manufacturing process. The magnet is temporarily softened for easy insertion, then quickly hardened in its final positioned state. This dynamic state change ensures ease of manufacture while restoring and maintaining full strength in the finished product.
Solution Approach 2:
The softening by reheating is performed as a preliminary action only during the insertion phase. Once the magnet is properly positioned in the yoke, the heating is stopped and the magnet is allowed to cool and harden, restoring its full strength and rigidity for long-term stability and performance.
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 stabilizes the press-fitting of bonded magnets, ensuring accurate inner surface alignment and reducing production costs while maintaining motor performance specifications.
Implementation Method 1
a softening step for reheating and softening the bonded magnet after thermal curing treatment
Implementation Method 2
a bonded magnet and a yoke are pressure-bonded to each other using a phenomenon that the bonded magnet disposed in the yoke oxidizes and expands by heating
Data Source
AI summary
A field magnet manufacturing method including reheating and softening a bonded magnet after thermal curing; and press-fitting the softened bonded magnet into a case from an opening on one side of the case. The case has a cylindrical portion and a lid portion coupled to another side of the cylindrical portion. The cylindrical portion has a fixing portion for the bonded magnet. At least the fixing portion is formed of a magnetic material. The press-fitting includes feeding the bonded magnet relatively into the cylindrical portion while allowing a relative posture variation between the bonded magnet and the case. This makes it possible to stably feed even the softened bonded magnet into the case, and the inner surface of the bonded magnet has a similar accuracy to that of the inner surface of the case.