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US 5,399,311 AGranted
Radial anisotropic ring magnet with a sinusoidal waveform and producing method thereof
AssigneeDaido Tokushuko Kabushiki Kaisha
InventorsYasuaki Kasai, Hiyoshi Yamada, Norio Yoshikawa
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Abstract
A magnet is formed as a ring magnet and magnetized by radial application of a magnetic field while the intensity of the magnetic field is changed periodically along the circumference of the ring magnet to give a circumferentially sinusoidal waveform distribution of magnetic flux density to the ring magnet in the magnetized state of the magnet.
Claims3
A method of producing a rare earth metal radial anisotropic ring magnet, comprising the steps of:
- forming by hot pressing and backward extrusion a ring-shaped preformed material having its wall thickness changed circumferentially and periodically;
- applying plastic working to said ring-shaped preformed material to make the wall thickness of said preformed material even so that the degree of said plastic working changes circumferentially;
- and
- magnetizing said preformed material by radially applying a magnetic field to give predetermined magnetic characteristic correspondingly to the degree of said plastic working to said preformed material so that said radial anisotropic ring magnet having a circumferentially sinusoidal waveform distribution of magnetic flux density is produced.
1 more element
A method of producing a rare earth metal radial anisotropic ring magnet, comprising the steps of:
- press molding a magnetic material powder into a ring while radially applying a magnetic field having an intensity varied circumferentially and periodically to said magnetic material powder;
- sintering said ring of said press molded magnetic material powder;
- and
- magnetizing said ring of said magnetic material powder to produce said radial anisotropic ring magnet having a circumferentially sinusoidal waveform distribution of magnetic flux density.
1 more element
Dependencies are inferred from the claim text.