Stamping of One-Piece Automobile Steel Wheels from Tube
A multi-stage stamping process of one-piece automobile steel wheels from tubes was developed to decrease the loss of material for the blanking. In this process, the tube is nosed into a cup with a central hole, and then the taper bottom and side wall of the cup are formed into disk and rim portions of the wheel, respectively. The tube is produced by bending a rectangular sheet into a tube and by welding both edges of the bent sheet to prevent the loss of material for the blanking. The stamping sequence of the one-piece wheels was designed by finite element simulation. The central hole of the cup was decreased to a desired diameter of the hub hole without buckling and wrinkling by a 5-stages nosing operation. The taper bottom of the cup was reversely drawn, and then was flared without folding by 2 stages. The wall thickness of the formed wheel was thick and thin in the disk and rim portions, receptively, and thus the requirement of strength of wheels is satisfied. A one-piece wheel having a hub hole was successfully formed by the designed sequence in a miniature experiment.