NdFeB magnet with low eddy current loss

Abstract

The invention provides a slotted neodymium-iron-boron magnet. The slotted neodymium-iron-boron magnet comprises a neodymium-iron-boron square magnet which is subjected to permeation treatment or not subjected to permeation treatment; and the groove is arranged on the surface of the neodymium iron boron square magnet. The neodymium-iron-boron square magnet with the slotting structure is flexible and changeable in slotting position and easy to operate, can be applied to different products by meeting the performance requirements of all parts, can reasonably select the slotting position according to the requirements, improves the magnetic performance of different positions, and improves the production efficiency. The motor is greatly helpful for improving torque output capability and reducing loss in high-speed operation, magnetic steel eddy-current loss is reduced, motor efficiency is improved, temperature rise of the rotor is improved, usage amount of heavy rare earth diffusion sources is reduced, and motor cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of NdFeB magnet preparation, relates to a slotted NdFeB magnet, and in particular relates to a NdFeB magnet with low eddy current loss. Background technique [0002] Sintered NdFeB rare earth permanent magnets have excellent hard magnetic properties and are widely used in new energy vehicles, smart communications and wind power generation. In recent years, sintered NdFeB magnets have been continuously improved and have more excellent magnetic properties, especially their strong magnetic field strength, high coercivity, and high temperature resistance are widely used in permanent magnet motors. A permanent magnet material itself has certain defects. [0003] In motor applications, as the speed or power of the motor increases, there is an eddy current effect in the NdFeB magnet, which will cause the temperature to rise. performance. When NdFeB magnets are used in motors, the magnetic properties of NdFeB mag...

AI Technical Summary

Problems solved by technology

[0003] In motor applications, as the motor speed or power increases, there will be eddy current effects in the NdFeB magnets, which will cause a rise in temperature. In the worst case, it may cause demagnetization of the NdFeB magnet materials, thereby greatly reducing the motor performance

When NdFeB magnets are used in motors, the magnetic properties of the NdFeB magnets will attenuate to a certain extent as the motor heats up. Due to the different temperatures at different positions of the motor, the magnetic properties of the NdFeB magnets at different positions will also attenuate. Different, but in the actual production process of NdFeB magnets, in order to ensure the magnetic performance in the highest temperature region, the performance of the whole magnet is often able to meet the magnetic performance attenuation requirements in the highest temperature region, which hinders the NdFeB magnet to a certain extent. Improvement of magnetic steel remanence and reduction of cost

[0004] In the prior art, the permanent magnets of motors are mostly made of NdFeB materials with high coercive force and remanence, which have high electrical conductivity and poor heat resistance. Compared with copper loss and iron loss, the eddy current loss of permanent magnet In most cases, it is not large, but for high-speed, high-power-density motors and closed-structure motors, the eddy current loss of NdFeB permanent magnets will cause a large temperature rise in the rotor part, and even cause irreversible permanent magnets in severe cases. Demagnetization, which is fatal for permanent magnet motors

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