Cold machining process of ultradeep-hole long and thin part and cold extruding stretching mold

Abstract

The invention discloses a cold machining process of an ultradeep-hole long and thin part and a cold extruding stretching mold, and belongs to the technical field of cold extruding. According to the cold machining process, the bar is subjected to alramenting according to part needs, and a hollow short pipe blank is formed; and then a hole protection needle stretches into a center through hole of the hollow short pipe blank, the hollow short pipe blank is cold-extruded and stretched to the length needed by the part and an ultradeep hole of the long and thin part is molded. The invention furtherdiscloses a cold extruding stretching mold for the cold machining process of the ultradeep-hole long and thin part. According to the cold machining process of the ultradeep-hole long and thin part andthe cold extruding stretching mold, the problem that an existing ultradeep-hole long and thin part is large in molding difficulty, poor in precision, low in machining efficiency and the like is solved, the machining efficiency and quality of the ultradeep-hole long and thin part are greatly improved, and the machining adaptability to the part is high; and the cold machining process can be used for cold machining molding of various ultradeep-hole long and thin parts, is theoretically not limited by the draw ratio of the parts, and is especially suitable for machining the ultradeep-hole parts large in draw ratio.

Description

technical field [0001] The invention relates to a cold working process and a cold heading die, more specifically, to a cold working process and a cold extrusion elongating die for ultra-deep hole slender parts. Background technique [0002] Slender parts with holes are a common type of parts in industry, such as figure 1 The hollow hanger screws used in the show bike stem and Figure 4 Hollow piston rods in electric bicycle shock absorbers, etc. Generally, a hole whose depth exceeds 5 times the diameter of the hole is called a deep hole, and the ratio of the depth of the hole to the diameter of the hole is called the "length-to-diameter ratio" or "depth-to-diameter ratio". Relatively speaking, a cylindrical hole with a length-to-diameter ratio of no more than 5 times can be called a "shallow hole", and it is relatively convenient to process and form; while for a deep hole, it is generally processed by boring or drilling, and for the hole depth and It is very difficult to ...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the shortcomings of existing ultra-deep hole slender parts such as the difficulty of cold heading and low efficiency, and provide a cold processing process and cold extrusion elongation die for ultra-deep hole slender parts. The technical solution is to first carry out surface phosphating treatment on the bar according to the needs of the parts to form a hollow short tube blank, and then use the grommet to extend into the central through hole of the hollow short tube blank, and under the protection of the grommet, the hollow short tube The tube blank is cold extruded and elongated to the required length of the part to form the ultra-deep hole of the slender part, which solves the problems of the existing ultra-deep hole slender parts such as difficulty in forming, poor quality, and low processing efficiency, and greatly improves the ultra-deep hole. The processing efficiency and processing quality of deep-hole slender parts, and the processing adaptability to parts, can be used for cold forming of various ultra-deep-hole slender parts. Theoretically, it is not limited by the length-diameter ratio of parts, especially suitable for large Machining of Ultra-deep Hole Parts with Length-diameter Ratio

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