| 摘要 |
PURPOSE:To obtain efficiently a nipple for vehicle by inserting a mandrel into a hole of a hollow state cylindrical steel material cut to a fixed size, forming a head part and a drum part by means of ironing and heading, and thereafter, expanding and opening an unloaded hole on the opposite side of the head part by ironing, and working a female screw hole. CONSTITUTION:A material B is obtained by cutting a wire rod having prescribed thickness and a hole (inside diameter) (b) to prescribed length. Subsequently, the material B is held by inserting a mandrel into the hole (b), a head part 11 and a drum part 12 are formed by executing ironing and heading from one side, and a round drum and a square drum are formed simultaneously as a conventional example. Next, the hole (b) is used as a guide and an unloaded hole 16 is expanded and opened by ironing on the opposite side of the head part 11, and thereafter, ironing is executed so that the hole (b) becomes a female screw hole 17. Subsequently, chamfering 15 and tap-finishing of a female screw 18 are executed and an object vehicle use nipple is obtained. According to this method, drill working can be omitted, a workability is improved, also a forging pressure of a heading is reduced, and the life of a metallic die is improved remarkably.
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