1.What is a radially oriented magnetic ring?

The Radially oriented magnetic ring is a type of specially oriented annular permanent magnet, which is magnetized in the radial direction around the circumference of the magnetic ring. The sintered NdFeB Radially oriented magnetic ring has a variety of magnetization methods, and can be used for uni-polar magnetization and multi-Poles magnetization as needed. Radially oriented magnetic rings can replace spliced arc magnets and are widely used in servo motors, magnetic drives,magnetic bearings and sensors.

At present, most of the mainstream permanent magnet motors are sintered NdFeb magnetic tiles using surface attachment or embedded splicing into a ring magnetic circuit, this installation has many Shortcomings:

①Splicing magnetic ring requires high precision and difficulty for the assembly of magnetic tiles, which increases the manual installation cost.

② Large transition area between magnetic tiles leads to poor smoothness of magnetic pole transition and serious motor noise.

③The structure requires a soft magnetic material frame structure to fix the magnetic tile, which affects the assembly efficiency.

The main advantages of Radially oriented magnetic rings include:

①The radially oriented ring is an integral magnetic ring, with better control of dimensional accuracy and simplified assembly process;

②The surface magnetic field is sinusoidal, evenly distributed, and the transition area between magnetic poles is small, so the motor operates stably and has low noise;

③ The magnetization methods and magnetic field distribution are diverse. It can be magnetized into uni-pole, multi-poles, and skewed pattern. The magnetic circuit design is more flexible.

The radially oriented magnetic ring is an integral magnetic ring that can maintain dimensional consistency after processing, which can effectively reduce the noise and vibration of the motor and improve the stability of the motor. Since the inner and outer surfaces of the entire magnetic ring can undergo radially oriented magnetization and multi-pole magnetization at a certain angle, and the transition area between magnetic poles is smaller, the performance of the motor can be significantly improved. The surface magnetic field of the multi-poles magnetic ring is distributed in the form of Sinusoidal curve. The ultra-high magnetic field can greatly improve the efficiency of the motor and make the motor lightweight and compact.

3.Manufacturing process type of NdFeB radially oriented magnetic ring:

NdFeB radially oriented magnetic rings are mainly divided into sintered radially oriented magnetic rings, bonded radially oriented magnetic rings and hot-pressed radially oriented magnetic rings according to different manufacturing methods. Due to the relatively mature bonding process and low price, the output of bonded NdFeB radially oriented rings accounts for the largest proportion. However, the density and performance of bonded magnetic rings are low, and high-end application scenarios are limited.

As for high-performance sintered and hot-pressed NdFeB radially oriented magnetic rings, due to the large differences in the shrinkage ratio and thermal expansion coefficient in the directions of the easy magnetization axis and the difficult magnetization axis of NdFeB grains, the preparation, magnetization and assembly processes are extremely difficult. It is easy to break, the yield is low, and the price is generally higher.

4.Regarding the size of the radiating ring:

①The bonded radiating ring is less limited by size;

②Hot-pressed rings are mostly thin-walled magnetic rings, with diameters mostly below 30mm and wall thickness below 3mm;

③Sintered radially oriented magnetic rings can be produced with a maximum outer diameter less than 200mm, a wall thickness exceeding 5mm, and a height less than 60mm. However, due to qualification rate and cost constraints, most of the products on the market are small-diameter magnetic rings with an outer diameter less than 100mm.

5.In conclusion

By reading this article, we hope to help you better understand the sintered NdFeB radially oriented magnetic ring.We have been engaged in the manufacturing of NdFeB magnets since 1994. With nearly 30 years’ production experience, we have developed our own technology to manufacture Nd-Fe-B magnets.

If you want to know more about our products, please see our video and other blogs, or contact us directly.Contact | HQ Magnet (hq-magnet.com)

Sintered NdFeB multi-poles magnetic ring – YouTube