| 摘要 |
PURPOSE:To produce a permanent magnet having high residual magnetic flux density by pressing anisotropic ferromagnetic powder within the impressed time of pulse magnetic field by an impulsive technique. CONSTITUTION:The pulse magnetic field generated by a method of flowing the instantaneous current generated by the electric discharge of a capacitor to an air core coil or the like are impressed to the powder consisting of fine particles of an anisotropic ferromagnetic material of rare earth metal-cobalt types or the like, and the powder is compression-molded impulsively by impulse compression with an air rifle or the like within the time when said pulse magnetic field exists. The molding is accomplished by shooting the bullet of an air rifle under acceleration with air pressure, disposing a photoelectric cell or the like in the trajectory in a suitable position until the bullet hits the press bar of the dies contg. the fine magnetic particle powder, detecting the passage of the tip of the bullet, triggering an electric power source for generating pulse magnetic fields to start electric discharge in accordance with said detection signal and impressing the pulse magnetic field to the powder prior to arrival of the bullet. |
