Applications and Advantages of Radially Magnetized Ring Magnets in Electric Motors

Radial ring magnets feature magnetic poles oriented radially from the center to the periphery. Their pole positions and pole pair counts depend on the magnetization method, of which there are numerous types. Based on magnetization techniques, they can be categorized into standard radial, multi-stage radial, and multi-pole skewed-angle radial magnets (where the final magnetizing fixture determines the number of poles and skew angle).

Radial ring magnets encompass sintered rare-earth magnets, sintered ferrite magnets, hot-pressed/hot-deformed magnets, and bonded magnets. The radial magnets commonly used and discussed are primarily sintered rare-earth magnets. Radial ring sintered magnets can be categorized by material into NdFeB and SmCo types, with sintered neodymium-iron-boron magnets typically employed in motor rotors.

Applications of Radial Ring Magnets in Motors;

Radially magnetized ring magnets are primarily used in brushless DC motors (BLDC), permanent magnet synchronous motors (PMSM), water pump motors, fan motors, and certain servo and encoder integrated motors. In internal rotor structures, the magnetic ring is typically mounted on the outer surface of the rotor core or shaft. In external rotor structures, it is fixed to the inner wall of the rotor cup. Multi-pole radial magnetization (e.g., 4-pole, 6-pole, 8-pole, and higher pole counts) facilitates smooth commutation and precise position detection in motors.

Advantages of radial magnets (magnetic rings) in motors:

The assembly process for motor assemblies is significantly easier than bonding arc magnets to rings, with substantially lower assembly costs.

Improved magnetic flux uniformity enhances motor efficiency. The assembly precision of radial ring magnets is significantly higher than traditional multi-arc assemblies, thereby improving motor dynamic balance.

Enhanced raw material utilization.

The above covers the relevant introduction to radial ring magnets.