A steel pipe shrinking die

Abstract

The invention discloses a steel tube necking die. The steel tube necking die comprises a base plate, a lower die assembly, guide shafts, a movable plate, an upper fixed plate, an upper die assembly, guide columns and an upper die plate. The guide shafts are installed between the base plate and the upper fixed plate. The guide columns penetrate through the upper fixed plate, the lower ends of the guide columns are connected with the movable plate, and the upper ends of the guide columns are connected with the upper die plate. The guide shafts are sleeved with the movable plate. The upper die assembly comprises an upper die sleeve, a large necking die body, a small necking die body, a mandrel and a guide sleeve. The upper die sleeve is fixed to the lower end face of the movable plate. The guide sleeve, the large necking die body and the small necking die body are stacked in a mounting hole from bottom to top. The large necking die body and the small necking die body are concentrically provided with a larger necking die cavity and a small necking die cavity. A core rod is fixedly connected with the upper die plate, and the lower end of the core rod extends into the guide sleeve. The lower die assembly is fixed on the base plate and used for installation of a steel tube. The steel tube necking die can achieve two-time necking through one-time downward pressing, it can be guaranteed that the center of the upper die assembly is accurately aligned to the center of the lower die assembly, it is ensured that the upper die assembly vertically press downwards, and the downward pressing stroke of a punch can further be reduced.

Description

technical field [0001] The invention relates to a shrinking die, in particular to a steel pipe shrinking die. Background technique [0002] The steel pipe whose end diameter has been reduced twice is used on the automobile shock absorber. However, the current shrinkage of the steel pipe is generally completed by two sets of shrinking dies. First, the end of the steel pipe is processed on the large shrinking die Neck once, and then shrink the part that has been shrunk twice on another small shrinking die. This method is inefficient, and the second necking is easy to damage the surface of the first necking, reducing the quality of the steel pipe. At present, there is also a necking die that can be pressed down twice to complete the necking. For example, the open text of the patent application number: 201310408181.7 discloses such a necking die. Necking, this structure has the following defects: 1. When the necking die is operated, it is necessary to put the lower end of the ...

AI Technical Summary

Problems solved by technology

This method is inefficient, and the second necking is easy to damage the surface of the first necking, reducing the quality of the steel pipe

At present, there is also a necking die that can be pressed down twice to complete the necking. For example, the open text of the patent application number: 201310408181.7 discloses such a necking die. Necking, this structure has the following defects: 1. When the necking die is operated, it is necessary to put the lower end of the steel pipe into the guide sleeve until the lower end touches the upper necking die; the guide sleeve not only serves as a guide, but more importantly, it assists the vertical Straight, so the machining accuracy is very high. Once the machining accuracy deviates, the concentricity between the upper shrinking die and the guide sleeve will deviate, which will directly cause the steel pipe to not be vertical when necking, thus affecting the necking accuracy.

2. The installation accuracy of the guide sleeve and the mold cover also affects whether the steel pipe is placed vertically and affects the accuracy of the necking

3. During the installation process of the shrinking mold, the concentricity between the upper mold assembly and the lower mold assembly is difficult to align

4. The necking die is unloaded by upward ejection, and at the same time, due to the existence of the guide sleeve, it is necessary to leave the upper necking die and the guide sleeve when taking out the steel pipe. Therefore, the upward movement distance of the upper necking die is longer , at least the sum of the length of the guide sleeve and the necking section, so that the stroke of the punch is longer and the necking speed is low

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