| 摘要 |
PROBLEM TO BE SOLVED: To provide a gear forming method in which underfill of a tooth portion is hard to occur.SOLUTION: There is disclosed a forming method by the forging of a gear. In the forming method, a tooth form is formed by a forming die 74, a lower punch, and an upper punch in the outer peripheral surface or the inner peripheral surface of a raw material 76. The upper punch has a first upper punch 66 and a second upper punch 68. The lower punch has a first lower punch 70 and a second lower punch 72. The forming method includes a first step in which the upper punch depresses the raw material toward the lower punch, and a second step in which, after the first step, while the first upper punch 66 depresses the raw material 76 toward the first lower punch 70, the second upper punch 68 is set back in regard to the first upper punch 66, and at the same time, the second lower punch 72 is set back in regard to the first lower punch 70. |
