Rie Yoshida, NICHIA CORPORATION
Although anisotropic rare-earth bonded magnets are inferior in magnetic properties to NdFeB sintered magnets, but they have higher magnetic properties than ferrite magnets and high flexibility of shape, so it’s expected as a material that lead to downsizing of in-vehicle motors. However, in the case of an anisotropic rare earth bonded magnet, the alignment direction and the its ratio at the time of injection molding affect the subsequent magnetization characteristics. So, it is difficult to expect accurately the surface magnetic flux density in the magnetization analysis from a thermal demagnetization state. Therefore, in this case, as a means of expecting the magnetic flux density of the anisotropic rare earth bonded magnet, while taking an analysis of the speaker magnet developed by our company as an example, we introduce a technique that utilizes alignment characteristics and thick-ness magnetization properties.