Currently, the mainstream design for permanent magnet brushless motors often involves assembling magnet tiles in a radial or embedded manner to form a ring. However, this method of magnet assembly has several drawbacks, including the need for high precision in magnet tile processing, assembly complexity, poor smoothness in magnetic pole transitions, significant motor noise, and the requirement for a framework structure made of soft magnetic materials to secure the magnet tiles. This framework structure leads to substantial magnetic flux losses, greatly impacting the power factor and efficiency of the motor.

Radiation magnetic rings offer significant advantages and effectively address the issues associated with assembled magnetic rings. The advantages of radiation magnetic rings are as follows:

1. Radiation rings are integral magnetic rings, which allows for better control over dimensional accuracy and simplifies the assembly process.
2. The magnetic field on the surface of the radiation ring exhibits a sinusoidal waveform with a uniform distribution. This results in stable motor operation and reduced noise levels, as there is minimal transition zone between magnetic poles.
3. Radiation magnetic rings offer diverse magnetization methods and magnetic field distributions. They can be magnetized with single-pole radiation, multi-pole direct magnetization, or multi-pole oblique magnetization, providing greater flexibility in magnetic circuit design.

These advantages make radiation magnetic rings a superior choice compared to assembled magnetic rings in various applications, particularly in improving motor performance and efficiency.

Radiation magnetic rings can be categorized into adhesive radiation rings, sintered radiation rings, and hot-pressed radiation rings. Due to the mature manufacturing process and cost-effectiveness, adhesive neodymium iron boron (NdFeB) radiation rings have the largest production share. However, adhesive rings have lower density and performance, limiting their use in high-end applications.

On the other hand, high-performance sintered and hot-pressed/hot-deformed NdFeB radiation rings have significant challenges in their production, magnetization, and assembly processes. This is because the shrinkage ratio and thermal expansion coefficient between the easy magnetization axis and hard magnetization axis of NdFeB grains are significantly different. As a result, these high-performance rings are prone to cracking, have lower yield rates, and are generally more expensive.