| 摘要 |
PURPOSE: To provide an improved method for working cylindrical sheet metal parts, a method, capable of preventing elastic deformation due to spring back phenomenon, for working cylindrical sheet metal parts, a method capable of preventing elastic deformation by forming a bump on free end, for working cylindrical sheet metal parts, and a die mold device capable of forming a bump adjacently to free end of the parts. CONSTITUTION: The die mold device for working cylindrical sheet metal parts comprises an inner die and an outer die which are respectively disposed at the inner side and the outer side of a cylindrical work(42), wherein shape of a space formed between the inner die and the outer die when they come close to each other corresponds to a fixed shape of the work; and bump forming parts(71-74) formed at the inner die and the outer die to prevent elastic deformation of a free end of the cylindrical work by forming a completely plastic deformed bump on at least one side of portions adjacent to the free end of the cylindrical work, wherein the work is disposed on a saddle(52), an outer die part(58) and an outer slider(56) are disposed on the cylindrical outer side of the work, an inner ram(53) and an outer ram(54) maintain the ascended state with being spaced from the saddle, an inner slider(55) and an inner die part(57) are spaced from the outer slider and the outer die part, horizontal external force is applied to the inner slider by lowering an inclination plane(53') formed on the inner ram in the state that the inclination plane(53') is contacted with an inclination plane(55') formed on the inner slider, and horizontal external force is applied to the outer slider by lowering an inclination plane(54') formed on the outer ram in the state that the inclination plane(54') is contacted with an inclination plane(56') formed on the outer slider.
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