Method for manufacturing rare earth permanent magnet ring by adopting hot pressing-thermal deformation process and special die

Abstract

The invention provides a method for manufacturing a rare earth permanent magnet ring by adopting a hot pressing-thermal deformation process. The method comprises the following steps of a hot pressingtreatment step: putting a rare earth permanent magnet powder into a hot pressing mold for hot pressing treatment to obtain an isotropic permanent magnet; and a thermal deformation treatment step: carrying out thermal deformation treatment on the isotropic permanent magnet to manufacture a radial rare earth permanent magnet ring. The method has the following advantages that 1) the adopted hot pressing-thermal deformation forming process is beneficial to uniform distribution of a high-temperature flow stress on the magnet and the magnetic ring, and is beneficial to improving formability and uniformity of the radiation orientation permanent magnet ring; 2) the internal stresses in the magnet and the magnetic ring can be effectively released in real time through an intermittent mode in the hotpressing and thermal deformation processes; and 3) a thermal deformation process link is directly entered into after hot pressing so that a cooling link after hot pressing and a heating link before thermal deformation are avoided, a friction degree between the magnet and the die is reduced, and stress reduction, grain refinement, process takt improvement, cost reduction and the like are facilitated.

Description

technical field [0001] The invention belongs to the field of manufacturing and processing of rare earth permanent magnet materials, and in particular relates to a method and a special mold for preparing rare earth permanent magnet rings by adopting a hot pressing-thermal deformation process, and is especially suitable for the preparation of thermally deformable high-performance anisotropic permanent magnet rings. Background technique [0002] Radiation-oriented rare earth permanent magnet rings have been applied in motors, such as brushless motors, AC servo motors, etc. There are many ways to prepare permanent magnet rings, such as splicing and bonding permanent magnets into permanent magnet rings. Inhomogeneity of the magnetic field occurs in the bonded splicing area; the rare earth permanent magnetic powder is bonded into a permanent magnetic ring by using an adhesive such as epoxy resin, but due to the existence of the adhesive, the magnetic performance is low. Therefore,...

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Problems solved by technology

However, the formation of the hot-pressed-hot-deformed magnet texture is closely related to the plastic deformation of the material. Due to the distribution of the loading force and the friction between the mold and the plastic deformation process from the magnetic powder particles to the block, the magnet deformation process The stress distribution is uneven. At the same time, due to the heating-cooling process from the magnetic powder to the magnetic ring, it is inevitable to generate obvious internal stress, which leads to the magnetic ring being easy to crack or the magnetic properties are uneven. The existing technology is still difficult to solve the release of internal stress. , then, how to release the internal stress during the hot pressing of the powder and the thermal deformation of the ring body has become a key technology to avoid cracking of the thermally deformed magnetic ring and improve the qualified rate of the magnetic ring

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