Patent ID: 7367791

Claim:
A device for producing one of an annular magnet and an arcuate magnet, comprising: a preforming section which includes a first die defining an outer peripheral part of one of an annular cavity and a plurality of arcuate cavities, each facing each other, a first core defining an inner peripheral part of one of said annular cavity and said plurality of arcuate cavities, a first lower punch defining a bottom of one of said annular cavity and said plurality of arcuate cavities, a first upper punch facing said first lower punch, and a rubbing jig which moves on said first die, one of said annular cavity and said plurality of arcuate cavities being charged with a compound as a mixture of an anisotropic magnet powder and a thermosetting resin in an amount which is in accordance with a volume of one of said annular cavity and said plurality of arcuate cavities by moving said rubbing jig, said compound being pressure-formed in one of said annular cavity and said plurality of arcuate cavities with said first upper punch and said first lower punch, thereby obtaining a preformed body; a magnetic field orienting and forming section for obtaining an intermediate formed body, which includes a second die for holding an outer peripheral surface of said preformed body, a second core for holding an inner peripheral surface of said preformed body, a second lower punch for holding a bottom of said preformed body, a second upper punch for facing said second lower punch, magnetic field applying means for applying a magnetic field to said preformed body, and heating means for heating said preformed body, a main forming section for obtaining one of an annular magnet and a plurality of arcuate magnets, which includes a third die for holding an outer peripheral surface of said intermediate formed body, a third core for holding an inner peripheral surface of said intermediate formed body, a third lower punch for holding a bottom of said intermediate formed body, a third upper punch for facing said third lower punch, and heating means for heating said intermediate formed body, and a work transferring section which holds said preformed body, and transfers said preformed body from said preforming section to said magnetic field orienting and forming section, and which also holds said intermediate formed body, and transfers said intermediate formed body from said magnetic field orienting and forming section to said main forming section, servomotors which drive said first through third upper punches, said first through third lower punches and said first through third cores respectively, a mass measuring means for measuring the mass of said preformed body after forming of said preformed body, and a control means which varies the position of said lower punch before pressure-forming with said servomotor, based on said mass of said preformed body, which has been measured with said mass measuring means, and varies a volume of one of said cavity and said cavities, thereby varying a charged amount of said compound.