BACK PRESSURE DEVICE FOR PROGRESSIVE DIE DEVICE AND PROGRESSIVE DIE DEVICE COMPRISING IT AS WELL AS BACK PRESSURE CONTROLLING METHOD IN PROGRESSIVE DIE DEVICE

摘要

PROBLEM TO BE SOLVED: To generate pertinent back pressure upon an iron core thin plate while preventing projection of the iron core thin plate with a simple construction in a back pressure device for progressive die device.SOLUTION: A back pressure device 6 for a progressive die device comprises: a receiving table 31 which is arrange in an elevatable manner in an iron core holding member holding an iron core thin plate 2 punched from belt-shaped thin steel plate W in the progressive die device 1 and on which the iron core thin plate 2 is serially loaded; a support unit 32 supporting the receiving table; an elevation motor 33 providing elevation action to the receiving table via the support unit; and a controlling device 34 controlling rotation action of the elevation motor. The controlling device sets a plurality of torque limit values for limiting output torque of the elevation motor according to action of the progressive die device. When punching of the iron core thin plate, output torque is limited based on the maximum torque limit value in the plurality of torque limit values.SELECTED DRAWING: Figure 1