Forming method and device of sintered Nd-Fe-B radiation magnetic ring

Abstract

The invention relates to a sintered Nd-Fe-B radiation magnetic ring, in particular to a static pressure forming method and device of the sintered Nd-Fe-B radiation magnetic ring. The problem that the orientation magnetic field strength and the magnetic ring height can not be considered at the same time in the production process of the sintered Nd-Fe-B radiation magnetic ring at present and the problem that the defective index is too high are solved. The method comprises the following steps that (1) magnetic field orientation preforming is conducted on magnetic powder to obtain preformed magnetic ring blank first; preforming pressure has to meet the demand of forming to fix the orientation of the magnetic powder, the compressed density space is also reserved for the magnetic ring blank, and the height of the magnetic ring blank meets the demand of the needed orientation radiation magnetic field strength; (2) a plurality of pieces of magnetic ring blank obtained in the step (1) are penetrated by one metal core shaft in a clearance fit mode, and a preforming magnetic ring combination is obtained; (3) the magnetic ring combination is subjected to isostatic pressing, the isostatic pressing removes the density space of the magnetic ring blank and the density space among the pieces of magnetic ring blank, and the pieces of magnetic ring blank are combined to a magnetic ring. The static pressure forming method is also suitable for other rare-earth permanent magnet sintered radiation magnetic rings.

Description

technical field [0001] The invention relates to magnetic materials, in particular to a sintered NdFeB radiation magnetic ring, in particular to a forming method and equipment for the sintered NdFeB radiation magnetic ring. Background technique [0002] Sintered NdFeB radiation-oriented magnetic rings can be magnetized not only into radiation magnetic rings but also into any multi-pole magnetic rings, which are suitable for the production of various high-performance permanent magnet motors in terms of magnetic performance and operating temperature. High-performance NdFeB or other rare earth sintered radiation magnetic rings also play an irreplaceable role in the field of national defense. [0003] Since some technological problems have not been resolved, sintered NdFeB magnetic rings have not been widely used so far. In order to fill this vacancy, people use the bonding process to produce NdFeB radiation magnetic rings or multi-pole magnetic rings. Among them, the isotropic ...

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Problems solved by technology

[0004] There are two difficulties encountered in the production process of sintered NdFeB radiation magnetic ring: 1. The first process of sintered magnet molding is magnetic field orientation molding. In order to achieve a high degree of orientation, the orientation magnetic field must reach a certain strength. For parallel magnetic fields There is not much difficulty with the vertical magnetic field, but the radiation magnetic field required for the orientation of the radiation magnetic ring is quite different. Since the magnetic field passing through the inner hole of the magnetic ring is limited by the magnetic saturation of the magnetic core, its magnetic flux is limited , these magnetic fluxes are distributed to the side of the magnetic ring to form a radiated orientation magnetic field. Since the area of ​​the outer surface of the magnetic ring is generally much larger than the area of ​​the inner hole of the magnetic ring, its magnetic field strength is much lower than the saturation magnetic field strength of the magnetic core. To obtain a certain intensity of the orientation magnetic field, we have to reduce the height of the magnetic ring to reduce the outer area of ​​the magnetic ring, which is usually much lower than the actual required height of the magnetic ring

2. The second process of sintered magnet molding is sintering. Since the orientation-molded magnetic ring blanks often have uneven density, most of them are deformed or cracked during the sintering process, and the yield is too low, which greatly improves the sintered NdFe The production cost of boron magnetic rings even makes the large-scale production of sintered NdFeB magnetic rings unfeasible

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