PURPOSE: To straighten the band of a crank shaft by deburring the blank material for the blank shaft forged by forging dies then rolling and pressing the same with rolling rolls having rolls conforming to the journal parts of the crank shaft.
CONSTITUTION: A round steel is heated and is forged to a blank material 11 for a crank shaft by forging dies. The burrs produced in this forging stage are removed by trimming dies. A bend is generated in the journal parts 12 of the material 11 from the devicated load and the uneven temp. distribution during cooling and the correction of the shape is required. Such material 11 is put between rolling rolls 9a, 9a rotated by a motor 6 and rolling rolls 9b as driven rolls and is rotated. The rolls 9a, 9b have the recessed grooves in the positions opposite to the journal parts 12 of the material 11 and the driven rolls 9b are pressed to said parts via a sliding head 5 by a hydraulic cylinder 4, whereby the bend in the journal parts 12 of the material 11 is straightened and the crank shaft having good accuracy in the balance is obtd.
NAGATSUMA NOBUYOSHI
NAKAMURA MITSUTERU
