Method for manufacturing constant velocity drive shaft

A method for manufacturing a constant velocity drive shaft using a closed cold forging device having a plurality of mold pairs structured with an upper mold and a lower mold, comprising:

• a first process for processing a forming material for forming the constant velocity drive shaft to form a first forming material having at least one first large diameter portion by applying a pressure of 2000 kN to 5000 kN from a first upper mold of a first mold pair and pressures of 2000 kN to 3000 kN from both sides in an axial direction of the forming material;
• a second process for forming a second forming material having at least one second large diameter portion by applying a pressure from a second upper mold of a second mold pair and pressures from both sides in an axial direction of the first forming material with respect to the first forming material having the at least one first large diameter portion being mold-processed in the first process;
• and
• a third process for forming at least one third large diameter portion by applying a pressure from a third upper mold of a third mold pair and pressures from both sides in an axial direction of the second forming material with respect to the second forming material having the at least one first large diameter portion and the at least one second large diameter portion being mold-processed in the second process.