Title:
ANISOTROPIC PLASTIC-BONDED MAGNET
Document Type and Number:
WIPO Patent Application WO/1991/001562
Kind Code:
A1
Abstract:
Hard ferrite magnetic powder of, e.g., barium ferrite or strontium ferrite, or rare earth magnetic powder of the Sm-Co or Nd-Fe-B is crystallized in a direction of crystal axis (C-axis) so that it may have the aspect ratio of the length of the crystal axis (C-axis) to the length of crystal face (C-plane) of 1:1 to 1:5. The crystalline magnetic powder possesses the effects of crystalline anisotropy and shape anisotropy. Three kinds of magnetic powders, i.e., a magnetic powder of 3 to 5 m$g(m) (0.05 to 0.1 m$g(m)) having the effects of crystalline anisotropy and shape anisotropy as a matrix, a magnetic powder of 1 to 3 m$g(m) (0.03 to 0.05 m$g(m)), and a magnetic powder of smaller than 1 m$g(m) (0.03 m$g(m)), are mixed together at a ratio that gives desired magnetic properties. The mixed powder may or may not be surface-treated with a silane coupling agent. This powder is then mixed with a small amount of a plasticizer and a parting agent, kneaded together with a thermoplastic resin or a thermosetting resin, and then pelletized. The pellets have a higher residual magnetic flux density (Br) and a smaller coercive force (Hc) than those of the general ones. Further, a rare earth permanent magnet such as Sm�x?Co�y? (Sm�1?Co�5?, Sm�2?Co�17?), Nd-Fe-B is buried in a metal mold, and is anisotropically oriented during the molding. Then, the pellets are injection-molded or compression-molded using a metal mold for polar anisotropic plastic magnet that has a coil wound in the metal mold to form the polar anisotropy as well as to effect the magnetization in the same metal mold, and to remagnetize the buried permanent magnet that is demagnetized.
Inventors:
MATSUYAMA YOSHIHIKO (JP)
Application Number:
PCT/JP1990/000827
Publication Date:
February 07, 1991
Filing Date:
June 26, 1990
Export Citation:
Assignee:
YUUGEN KAISHA KANEX (JP)
International Classes:
H01F1/055; H01F1/057; H01F1/113; H01F41/02; H02K15/03; (IPC1-7): H01F1/08; H01F1/113
Foreign References:
| JPS5589462A | 1980-07-07 | |||
| JPS6010278A | 1985-01-19 | |||
| JPS61170002A | 1986-07-31 | |||
| JPS6448402A | 1989-02-22 | |||
| JPH01131259A | 1989-05-24 |
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