Patent ID: 10005121

Abstract:
In a forming apparatus, stationary journal dies (10U, 10B) and movable journal dies (11U, 11B) each hold and retain rough journal portions (Ja) of a preform blank (4) therebetween, and crank pin dies (12) contacts rough crank pin portions (Pa) thereof, and in this state, the movable journal dies (11U, 11B) are moved axially toward the stationary journal dies (10U, 10B) and the crank pin dies (12) are moved in the same axial direction and in an eccentric direction. With this, weighted rough arm portions (Aa) are axially compressed to reduce their thickness to that of weighted arms of a forged crankshaft, and the rough crank pin portions (Pa) are pressed in the eccentric direction to increase the amount of eccentricity to that of the crank pins of the forged crankshaft.