| 摘要 |
A tube bulger for producing an enlarged ring-like bulge in the material around an end portion of a metal tube includes upper and lower die sections. When the upper and lower die sections are mated together, a cylindrical hole is formed. The end portion of the tube to be bulged extends into the hole. A ring-like, outwardly oriented enlargement of the cylindrical hole in the mated die sections forms a bulge cavity into which the bulge moves as it is being formed. An elongated mandrel extends through the opposite end of the cylindrical hole and into the open end of the tube. First and second sealing rings disposed about the mandrel on opposite sides of the bulge cavity prevent leakage of pressurized oil between the die and the mandrel. An oil conducting channel has an opening between the sealing rings. A high pressure oil source forces oil through the channel, out of the opening, thereby applying high pressure to the inner wall of the tube between the first and second sealing rings, causing an initial outward bulging of the tube into the bulge cavity. An enlarged shoulder of the mandrel abuts the open end of the tube, and is moved inward toward the recess, sliding the extreme end portion of the tube toward the bulge cavity. The partially formed bulge engages the wall of the bulge cavity, preventing sliding of the portion of the tube on the opposite side of the bulge cavity. Additional tube material then moves into the bulge cavity while the high pressure continues to be applied. Additional bulging occurs, causing enlargment of the bulge until it fills up the bulge cavity without excessive thinning of tube material in the bulge.
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