Bound magnet, its manufacture and driving device using the same


Application Number: 00108873
Application Date: 2000.05.19
Publication Number: 1274933
Publication Date: 2000.11.29
Priority Information: 1999/5/19 JP 138597/99; 1999/12/20 JP 361781/99
International: H01F1/08
Applicant(s) Name: Toshiba K. K.
Address:
Inventor(s) Name: Nakagawa Katsutoshi;Kawashima Fumiyuki;Nakagawa Katsutoshi
Patent Agency Code: 31100
Patent Agent: liu libeng
Abstract The invention improves magnetic characteristics, such as maximum energy product, etc., of a bonded magnet, using a magnet material containing a TbCu7 crystal phase as the main phase and the corrosion resistance of the magnet by further increasing the molded-body density of the magnet. The bond magnet comprises a molded body in which a mixture of flake of magnet material comprising rare earth element-iron-nitrogen as main component, TbCu7 type crystal phase as a principal phase and a thickness of less than 200 mum a binder is compression molded. A molded body constituting a bond magnet has a density of 6×10<3> kg/m<3> or more. In the step of compression molding a mixture of magnet material and binder, pressure is applied a plurality of times, or pressure is applied while rotating a punch and die, or the binder is cured while applying pressure to obtain such a bond magnet with good reproducibility. Such a bond magnet has excellent magnetic properties and corrosion resistance.