US 11,657,939 B2
Magnetic field generator, method for manufacturing magnetic field generator, and linear motor using magnetic field generator
Satoshi Imamori, Hino (JP); and Terukazu Akiyama, Hachioji (JP)
Assigned to FUJI ELECTRIC CO., LTD., Kawasaki (JP)
Filed by FUJI ELECTRIC CO., LTD., Kawasaki (JP)
Filed on Jan. 24, 2022, as Appl. No. 17/582,831.
Claims priority of application No. JP2021-037695 (JP), filed on Mar. 9, 2021.
Prior Publication US 2022/0293320 A1, Sep. 15, 2022
Int. Cl. H01F 7/02 (2006.01); H01F 41/02 (2006.01); H02K 41/03 (2006.01)
CPC H01F 7/0242 (2013.01) [H01F 41/0253 (2013.01); H02K 41/031 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A magnetic field generator comprising:
a yoke; and
a plurality of main magnetic pole magnets and a plurality of secondary magnetic pole magnets, the main magnetic pole magnets and the secondary magnetic pole magnets comprising a rare earth sintered magnet, having magnetic pole orientations different from each other by substantially 90°, and being alternately arranged in a linear Halbach magnet array without gaps and fixed to the yoke,
wherein near contact surfaces of the main magnetic pole magnets and the secondary magnetic pole magnets, a grain boundary diffusion layer is formed in which at least one of Dy or Tb being heavy rare earth elements or a compound of at least one of the Dy or the Tb is diffused into internal grain boundaries from the contact surfaces.