发明名称 BENT PIPE AND MANUFACTURE OF BENT TUBE BY PLASTIC WORKING
摘要 PROBLEM TO BE SOLVED: To manufacture a pipe which is hard to leave chips and sand on the inner wall-surface of a hole by forming an expanded part on the pipe by plastic working and bending that part at a prescribed angle. SOLUTION: A piece 31 of a solid base stock is formed into a thing having a blind hole 33 whose cross section is circular in a round bar 32. Two holes 35, 36 having different diameters are formed inside a cylindrical base stock 34 by forging the round bar 32. A pipe stock 37 having the same outside diameter, inside diameter and thickness is made by cold forging the cylindrical base stock 34. Using six dies 38-43, the pipe 44 is formed. The pipe 44 has the expanded part 44a formed by plastic working in the middle part and linear parts 44b, 44c on both sides. In the expanded part 44a, the shape and thickness on the upper and lower sides are different. By bending the pipe 44 having the expanded part 44a with bending dies 51-56, a bent part is formed. It is preferable to form the bent part in a state where the part is heated to 650-800 deg.C.
申请公布号 JP2000094042(A) 申请公布日期 2000.04.04
申请号 JP19980280503 申请日期 1998.09.17
申请人 KONDOO SEIKOO KK 发明人 TANABE KEIJI
分类号 B21D7/00;B21D7/16;B29C53/08;F16L43/00;(IPC1-7):B21D7/00 主分类号 B21D7/00
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