As the core component of a motor, the injection molded magnetic rotor's mounting method directly impacts the equipment's operational stability and service life. Currently, the industry's mainstream mounting technologies have developed diverse solutions to meet the needs of motors of varying power and operating conditions.
Injection molding integral forming fixation is the preferred solution for small and medium-power motors, accounting for 58% of the market application rate. During the injection molding process, this process tightly bonds the magnets to the rotor core with molten plastic, forming a seamless, integrated structure with radial runout controlled to within 0.03mm. In equipment such as washing machine motors and fans, it can withstand the centrifugal forces of high-speed rotation at 10,000 rpm without requiring additional assembly steps, improving production efficiency by 40%.
Adhesive fixing, due to its flexibility, is widely used for rotors with irregular structures. High-temperature-resistant epoxy adhesive (temperature resistance ≥180°C) is used to bond the magnets to the core surface, and a positioning fixture is used to ensure coaxiality ≤0.05mm. In water pump motors of new energy vehicles, this method can adapt to temperature cycles from -40℃ to 150℃, with a bonding strength of 15MPa, meeting the requirements of vibration tests.
Mechanical buckle + injection molding composite fixation focuses on high-power scenarios. Magnetic steel is pre-positioned through metal buckles, and then injection molding is used to fill gaps, increasing torsional moment resistance to 80N・m, which is 50% higher than that of single methods. Tests by an industrial motor manufacturer show that after 2,000 hours of continuous operation, there is no displacement of magnetic steel in this structure.
| Fixation Methods | Core Advantages | Applicable Scenarios | Reliability Indicators |
| Injection Molding Integral Forming | High efficiency, no assembly gaps | Household appliance motors, small water pumps | No loosening at 10, 000rpm |
| Adhesive Bonding | Adaptable to irregular structures, good temperature resistance | Automotive auxiliary motors, precision instruments | No detachment in -40℃~150℃ cycles |
| Mechanical Buckle + Injection Molding | Strong torsional resistance, high load capacity | Industrial drive motors, new energy motors | No displacement after 2, 000 hours of operation |
As motors develop toward higher speed and miniaturization, the fixation methods of injection molded magnetic rotors are trending toward compounding. For example, in drone motors, the "buckle positioning + laser welding + injection molding sealing" triple fixation is adopted, which not only ensures precision but also improves the protection level to IP68. In the future, the combination of new engineering plastics and magnetic materials will further optimize the balance between cost and performance of fixation processes.
