What Are The Advantages And Disadvantages Of Sintered NdFeB Radiating Magnetic Rings For Motors?

Sintered NdFeB radiation (multi-pole) magnetic ring is a new product developed in recent years, and it is another new direction for the development of sintered NdFeB permanent magnet materials. Mainly used for high-performance permanent magnet motors and sensors, it has the advantages of high precision, stable operation and low noise, and is the first choice for high-speed and high-precision control of motors. Widely used in high-speed drive motors, servo motors and other industrial equipment automation, digitalization, intelligent equipment. With the automation and precision of equipment and the development of permanent magnet motor design and control technology, high-performance permanent magnet servo motors using sintered NdFeB multipole radiating magnetic rings have begun to be used in automobiles, CNC machine tools, household appliances, computers, and robots. and other fields, has broad application prospects.

In the application of permanent magnet motors, sintered NdFeB magnet tiles are usually bonded into a ring, which has a series of disadvantages: the processing of tile-shaped magnets belongs to special-shaped processing, and the processing accuracy of angles, inner and outer surfaces, etc. The dynamic balance of the ring is poor, and the resulting transition area between the magnetic poles is large, which makes the motor generate noise and vibration. The installed rotor has been magnetized, making manual grinding more difficult, greatly increasing the amount of labor and the installation cost.

NdFeB radiation (multipole) magnetic ring can be divided into: bonded NdFeB radiation (multipole) magnetic ring, hot extrusion NdFeB radiation (multipole) magnetic ring, powder metallurgy sintered NdFeB radiation (multipole) magnetic ring pole) magnetic ring. Advantages of bonded NdFeB radiating (multi-pole) magnetic rings: no magnetic field limitation, simple molding. Disadvantages: low performance, expensive. Hot-extruded NdFeB radiation (multi-pole) magnetic ring, advantages: no magnetic field limitation, more suitable for preparing radiation rings, disadvantages: high cost.

Radial sintered ring magnets, whose magnetic fields can be aligned in different directions than "normal" neodymium ring magnets, can be produced in a single ring and in multiple directions during the manufacturing process. Radial neodymium rings make it possible to create complex magnetic applications in unusual ways. For example, the classic design of a magnetic rotor is done by placing arc segment magnets on a ring, with each segment magnetically aligned (north or south) in the opposite direction to the next magnet. Using radial sintered rings, opposing magnetic fields (4, 8 and more circular multipole magnets) can be generated in a single magnet in the same process. This is not possible in any other technique, this particular technique requires special tools for each specific magnet (die and magnetic coil for magnetization).

The radiating ring is an integral magnetic ring, which can maintain the consistency of size 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 be radiated and multi-pole magnetized at a certain angle, the transition area between the magnetic poles is small, which can significantly improve the performance of the motor. The surface magnetism of the multi-stage magnetic ring is distributed in the form of a sine wave, and the ultra-high magnetic field can greatly improve the efficiency of the motor, making the motor lightweight and miniaturized.

The sintered NdFeB radiation magnetic ring has a variety of magnetization methods, which can be single-pole magnetized and multi-stage magnetized according to needs. The size factors of the radiation magnetic ring include outer diameter, inner diameter and height. According to the outer diameter and wall thickness (inner diameter ratio), the radiating ring can be divided into the following categories: the outer diameter of 49mm or less is called ultra-small diameter ring, the outer diameter of 50~99mm is called small diameter ring, the outer diameter of 100~149mm is called For the middle diameter ring, the outer diameter of 150~199mm is called the large diameter ring, and the outer diameter of more than 200mm is called the super diameter ring. Chamber wall thickness: inner diameter ratio less than 0.7 is called thick-walled ring, and inner diameter ratio greater than 0.9 is called thin-walled ring.

In conclusion

The production process of sintered NdFeB radiant ring is complex and difficult, so the price is generally high. At present, there are not many manufacturers in the world that can produce large-diameter radiant rings with a diameter of more than 300mm.