| 摘要 |
A method and a device for cold forging of an automatic transmission shaft plant carrier with an involute spline are provided to obtain improved tooth accuracy, tooth strength and tooth durability by cold forging the forming material while maintaining a metal flow of a forming material, and reduce maintenance cost by increasing strength and durability in a boundary portion between a flange part and a body part. A method for cold forging of an automatic transmission shaft plant carrier with an involute spline comprises: a step(S1) of forming a first preform in which a cylindrical groove is formed by descending a top mold including a first outer punch and a first inner punch and pressing a forming material, thereby flowing the forming material into an empty space between the first inner punch and a first forming member of a lower mold and flowing the forming material into an empty space between the first outer punch and the first inner punch; a step(S2) of forming a second preform in which a flow of a metal material is maintained in a boundary part between the flange part and the body part, and a flow of the metal material is maintained in the body part by descending a top mold including a second punch and pressing the first preform, thereby forming the first preform into a flange part and a body part and forming the body part in two stages; a step(S3) of forming a third preform in which a hollow part passing through a flange part and a body part is formed by descending a top mold including a third inner punch, thereby pressing the second preform; and a step(S4) of forming a final form having improved tooth accuracy of the involute spline by descending a top mold including a fourth inner punch and a fourth outer punch and pressing the third preform, thereby forming an involute spline in the body part such that a flow of the metal material is maintained in the involute spline and inserting the fourth inner punch into the third preform such that a hollow part of the third preform maintains a constant inner diameter when the third preform is pressed. |
