PURPOSE: To provide a forging method of a drum with middle shaft which can improve the material yield, reduce the forging force, improve the life of die, and shorten the cutting time of cutting part.
CONSTITUTION: A die 22 having a forming recessed part 22 on its center part and a punch 32 having a cylinder part 31 to insert into this forming recessed part 21 forge and form a drum with a middle shaft consisting of the middle shaft 2 at the center part, a drum part 3 of its outer circumference and an end wall part 4 connecting the middle shaft 2 and the drum part 3. An annular taper surface 35 that its outer circumferential side is higher than its inner side is pre-formed on the outer circumferential side part, at least, of the lower end surface of the cylinder part 31 of the punch 32, and in a forging time, the flow of forming raw material into the drum part 3 through the annular taper surface 35 of the punch 32 is promoted.
ITO YOSHIMASA
TACHIBANA HIDEKI
ITO KAZUYA
