Kabushiki Kaisha Sankyo Seiki Seisakusho

Sankyo Seiki Mfg. Co., Ltd

Shigeru Nishida

Takafumi Kuwazawa

Tetsuo Hoshina

A motor having rotor has a good balance of inertia and a magnetic characteristic that match the specifications of the motor with which those rotors are to be used. A rare-earth containing iron-base resin-bonded magnet is molded from an iron-base magnetic powder containing a rare earth metal such as neodymium and praseodymium in powder, a thermoplastic or thermosetting resin and additive. A density and magnetic characteristic is proportionally changed by adjusting a mixing ratio of a filler powder. Specifically, when a mixing ratio of filler powder containing tungsten having a density 19.1 g/cm.sup.3 is in 13 vol % is injected, or a mixing ratio of alloy powder containing tungsten an nickel, or tungsten and chromium having a density 10.5 g/cm.sup.3 is compression-mold, its magnetic flux assume the same value as those of compression-molded Sm--Co magnets.

Rare-earth containing iron-base resin bonded magnets

A method of manufacturing a resin bound magnet comprising, mixing and kneading a powdered magnetic material and a rubber modified epoxy resin obtained from the addition polymerization of an epoxy resin and a butadiene or nitrile rubber and thereafter molding and setting the kneading mixture into a desired shape. The magnets prepared by the present invention exhibit permanent deformation under low compressive force, are soft and heat resistant and yet highly elastic and possess low dynamic exothermic properties and excellent low temperature characteristics. In addition, the inventive magnets exhibit excellent radial compression strength and other mechanical properties.

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Nagano, Japan

Shigeru Nishida