PURPOSE: To obtain an iron core having a diameter high in dimensional accuracy by detecting the diameter of the iron core while elastic deformation is recovered, feeding back this detected value to a roll guide drive part for regulating the iron core diameter, correcting the position of the roll guide and controlling the diameter of the iron core.
CONSTITUTION: The diameter of the iron core 1' forming a rolling angle, a rolling down force of rolling rolls 2, 2 is set a little larger than a target value. A belt-like sheet 1 is roll-bent by rolling rolls 2, 2 to form a helical iron core 1'. The outer periphery of the iron core 1' is in a free state behind the roll guide 3 for regulating the iron core diameter. The diameter of the iron core 1', that is, the distance of the butted point of the roller guide 3 to a photoelectric element 5 is detected and inputted into a controller part 6. When this detected value is larger than the target value, the applied voltage of a controller part 6 to the piezoelectric element 4 rises to elongate the piezoelectric element, to compress the iron core and to correct the target value. By this method, irrespective of the amount of the elastic deformation, it is possible to manufacture an iron core having a diameter high in dimensional accuracy.
SUZUKI TAKAMICHI
TAKASAKI MITSUHIRO
SUZUKI SHOJI
OCHIAI IZUMI
