METHOD AND APPARATUS FOR APPLYING MULTIPOLAR MAGNETIC FIELD TO PLURALITY OF CAVITY DEMARCATED TO MAGNETIC FIELD INJECTION MOLDING DIE

摘要

PURPOSE:To decrease the number of exciting coils, and to take out a large number of resin magnets brought into a multipolar anisotropic state by inducing a magnetic field to a common magnetizing yoke connecting adjacent cavities, distributing the magnetic field into each cavity and feeding back the magnetic field to a closed loop. CONSTITUTION:A plurality of cavities 22 are demarcated in a movable side die 18 in predetermined arrangement, and the adjacent cavities 22, 22 are connected in common by each magnetizing yoke 24. A magnetic field excited by an exciting coil 27 is induced in a path of a yoke 26 for inducing a first magnetic field, a magnetizing yoke 24, a yoke 28 for inducing a second magnetic field, a movable die 30a and a tie bar 30b to form a closed loop of the magnetic field. The number of the exciting coils requiring at least n/2 (n represents the number of magnetizing yokes) per each cavity in conventional devices can be decreased largely.