Minebea Company, Limited

Shinsaku Nishimura

Noboru Menjo

Fumitoshi Yamashita

Toshihiko Miura

There is provided the manufacturing method of a laminated magnet film end product, including the steps of: a first step of preparing magnet films, each of the magnet films having a thickness of 40 &#x3bc;m to 300 &#x3bc;m, and having a nanocrystalline structure which is magnetically isotropic; a second step of applying a self-bonding resin composition with film formability on each of the magnet films so as to prepare a plurality of self-bonding magnet films, each being composed of a magnet film and a self-bonding layer; a third step of mechanically processing each of the plurality of the self-bonding magnet films so as to be solid or hollow disc; a fourth step of preparing a laminated magnet film by laminating the plurality of self-bonding magnetic films; a fifth step of melting each self-bonding layer of the laminated magnet film and then cooling and solidifying each self-bonding layer so as to integrally rigidify the laminated magnet film; and a sixth step of magnetizing the rigidified laminated magnet film.

Manufacturing method of laminated magnet film end product with self-bonding layer

A micro rotor is disclosed and includes a plurality of circular or annular plate-shaped thick film magnets which each include an isotropic magnet with a thickness thaving an in-plane remanence Mr of 0.95 T or more and a coercivity HcJ of 400 kA/m or more and a non-magnetic material with a thickness tadapted to isolate two adjacent isotropic magnets where the ratio of t/tis eight or more and which are stacked on one another in multiple layers in the rotation axis direction, wherein at least two pole pairs are provided and a mean magnetic path of in-plane direction having a permeance (B/&#x3bc;oH) of five or more achieved by the magnet alone is provided, whereby eddy current is reduced. Also disclosed are a radial gap type brushless DC motor, a PM stepping motor and an electric generator which incorporate the above described micro rotor.

Micro rotor and rotary electric machine incorporating same

In a rare earth bonded magnet comprising a mixture of rare earth magnetic powder, thermosetting resin, and lubricant, the lubricant is constituted by amino-acid compound, specifically either N-lauroyl-L-lysine or N-lauroyl-asparaginic acid. The content of the amino-acid compound as lubricant in the mixture is set to range between 0.01 wt % and 1.0 wt % of the magnetic powder. Since the amino-acid compound has a high decomposition point, the resultant magnet after heat-curing treatment has a sufficient mechanical strength. Also, the amino-acid compound is nonhygroscopic, and therefore oxidation resistance and humidity resistance are good enough. Further, since the amino-acid compound produces a small amount of outgas, the resultant magnet can be suitably and reliably used in a hard disk drive which has stringent requirements, especially on outgas.

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Kitasaku-gun, Japan

Shinsaku Nishimura