| 摘要 |
PROBLEM TO BE SOLVED: To easily and inexpensively increase the surface roughness of the peripheral surface of a gear through window by forming the through window which is penetrating between a boss and a rim by hot forging or warm forging and formed smaller than the regular finish dimension to the regular finish dimension by old coining. SOLUTION: A steel bar is cut, heated to the temperature suitable for the hot forging, pressed for swaging, and formed in the shape of a gear, in particular a transmission gear, to obtain a stock similar in contour in which no through window is formed. The stock is bottom-punched in the hot forging process, a through window smaller than the regular finish dimension is formed in the window-punching process, the through window is expanded through the cold coining in the cold forging process after the annealing process, etc., to form a through window of the regular finish dimension. The through window smaller than the regular finish dimension may be formed in the warm forging process according to applications or materials.
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