A sawtooth-shaped push head for high-pressure forming in pipes

Abstract

The invention relates to a zigzag push head for tube hydroforming. The zigzag push head comprises a push head body, a zigzag seal head is arranged at the front end of the push head body and comprises a guide head and a zigzag seal segment located behind the guide head, the guide head is a cylinder with the diameter smaller than the inner diameter of a tube blank, and the front end of the guide head is chamfered; the zigzag seal segment comprises N round bosses equal in length, the diameters of the N round bosses are gradually increased in a equal difference mode, the diameter of the first round boss is larger than that of the guide head cylinder, the diameter of the last round boss is smaller than that of the push head body, and the slope of 15-20 degrees is formed between the outer diameter of the first round boss and the last round boss; N is any integer ranging from three to five. The push head is high in airtightness with the end of the tube and can prevent the guide segment from being stuck, and it is avoided that radial force is generated under the action of thrust to cause radial expansion of the tube end, and consequently the tube is stuck in a mold cavity; material feed and supplementary are smoother and more uniform, which is beneficial for tube blank forming.

Description

technical field [0001] The invention relates to a high-pressure forming die, in particular to a zigzag pusher used for high-pressure forming in pipes. Background technique [0002] Pipe internal high pressure forming is a method of filling the pipe with liquid and pressurizing it, and applying lateral thrust in the axial direction to feed the material, forcing the pipe blank to fit into the mold cavity under the pressure of the pressurized medium, so as to realize the tube blank forming. process, the pressure inside the pipe is generally as high as 100MPa-400MPa, and most of the formed parts need to be kept under high pressure for a period of time to achieve a good forming effect, so the sealing structure of the pipe end is good or bad. It is very important for the internal high pressure forming process, which directly affects whether the ultra-high pressure state can be realized, and thus affects whether the forming of pipe parts can achieve the expected effect. [0003] T...

AI Technical Summary

Problems solved by technology

[0004] 1. During the process of pressing the main body of the push head, the feeding resistance of the tube blank is often increased or stuck in the mold cavity, which causes the mold or the push head to be worn, deformed and damaged, which seriously affects the service life and reliability of the mold and push head. ;

[0005] 2. The use of this type of pipe end sealing structure is likely to cause radial expansion of the pipe opening, thereby increasing the difficulty of feeding the pipe blank, resulting in thinning or rupture of the pipe wall during forming. In severe cases, the push head and pipe fittings will be directly stuck in the joint. In the mold cavity

[0006] 3. The sealing structure disclosed in Chinese patent CN101011715, one is that it is easy to cause bulging at the left and right guide holes at both ends, and the other is that the use of this sealing structure requires an additional pusher structure of "with the cavity" and "guide hole". Complicated, poor manufacturing process, high manufacturing cost, and soft rubber, due to the high internal pressure, it is very easy to wear and often needs to be replaced, which not only increases the cost, but also wastes time

[0007] 4. The sealing structure disclosed in Chinese patent CN202097262U is also provided with a tapered sealing surface. Although it is also provided with a thrust table, under the action of a large axial thrust of the push head, the pipe material in contact with the push head thrust table is prone to damage. Collapse, at this time, due to the existence of the conical sealing surface, the radial expansion of the nozzle will also be caused during the process of the push head continuing to feed, which will increase the difficulty of feeding the tube blank, resulting in thinning or rupture of the tube wall during forming; When there are machining errors in the processing of the conical surface sinking of the pipe end, due to the deep depth of the conical surface sinking of the pipe end, it is easy to cause the radial expansion of the pipe opening and the excessive depth of the sinking table of the pipe end, resulting in poor sealing of the conical sealing surface

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