| 摘要 |
PROBLEM TO BE SOLVED: To provide a spinning forming method which can bring a sufficient increase of wall thickness without pressing a pipe end by a pressing tool. SOLUTION: In the spinning forming method, a forming roller 11 is moved in both a radial and axial directions of a tubular material W while being revolved around it and forms a tapered section Wa which has a gradually reducing diameter toward its tip and a straight section Wb with a small diameter in the end part of the tubular material W. In the initial and middle stages, as shown in figure (1), the forming roller 11 is reciprocatingly moved in the inclining direction to the axis O of the tubular material W to squeeze the end portion W' of the tubular material W into the tapered shape while sufficiently increasing the thickness in the end portion W'. In the final stage, as shown in figure (2), the forming tool 11 is reciprocatingly moved in both parallel and inclining directions to the axis O of the tubular material W to form both the tapered section Wa and the straight section Wb with the small diameter while securing the sufficient thickness in the tapered section Wa, straight section Wb and the boundary section Wc. COPYRIGHT: (C)2004,JPO
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