Method for manufacturing constant velocity drive shaft
The prevent invention proposes to provide a method for manufacturing a constant velocity drive shaft, which can manufacture especially a constant velocity drive shaft among other drive shafts with efficiency and stable high accuracy. The 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, comprises a first process for processing a forming material for forming the constant velocity drive shaft to form a first forming material having first large diameter portions by applying a pressure from a first upper mold of a first mold pair and pressures from both sides of the forming material, a second process for forming a second forming material having second large diameter portions by applying a pressure from a second upper mold of a second mold pair and pressures from both sides of the first forming material with respect to the first forming material being mold-processed in the first process, and a third process for forming third large diameter portions by applying a pressure from a third upper mold of a third mold pair and pressures from both sides of the second forming material with respect to the second forming material being mold-processed in the second process.
1 . 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.
2 . The method for manufacturing the constant velocity drive shaft according to claim 1 , wherein
the first mold pair has at least one first cavity having a concave shape for forming the at least one first large diameter portion, and walls on both sides of the concave shape of the at least one first cavity has a tapered shape.
3 . The method for manufacturing the constant velocity drive shaft according to claim 1 , wherein
the second mold pair has at least one second cavity having a concave shape for forming the at lease one second large diameter portion, and at least one first cavity for maintaining the shape of the at least one first large diameter portion contained in the first forming material,
and walls on both sides of the concave shape of the at least one second cavity has a tapered shape.
4 . The method for manufacturing the constant velocity drive shaft according to claim 1 , wherein
the third mold pair has at least one third cavity having a concave shape for forming the at least one third large diameter portion, and at least one first cavity and at least one second cavity for maintaining the shapes of the at least one first large diameter portion and the at least one second large diameter portion contained in the second forming material,
and the at least one third cavity has a tapered shape only on one side of the concave shape.