Method for manufacturing conical riser of direction column of motorcycle by adopting cold extrusion process

Abstract

The invention relates to a method for manufacturing a conical riser of a direction column of a motorcycle by adopting a cold extrusion process, which comprises the steps of: firstly, performing surface decontamination derusting treatment on a straight steep pipe blank; then cold-extruding the straight steep pipe blank into a conical riser blank; and finally performing end surface chamfering, fine turning of surface bearing positions and thread rolling treatment of thread sections on the conical riser blank to obtain a finished product of the conical riser. The cold extrusion working procedure comprises the steps of: placing the straight steep pipe blank into a cold extrusion mold cavity, then starting a press to ensure that a male mold end on the press aligns with the end surface of the straight steep pipe blank, and only slowly imposing an axial pressure on the straight steep pipe blank to make the straight steep pipe blank extruded and molded into the conical riser blank in the cold extrusion mold cavity, wherein the male mold end is provided with a positioning boss matched with an inner hole of the straight steep pipe blank. The method has the advantages of needing low cost for raw materials, greatly improving the strength of a large end of the produced conical riser, and having no cracks on the large end during the production, thereby improving the qualification rate of products.

Description

technical field [0001] The invention relates to a cold extrusion forming process in the mechanical processing industry, in particular to a method for manufacturing a motorcycle steering column tapered standpipe by using the cold extrusion process. Background technique [0002] Such as figure 1 As shown, the motorcycle steering column tapered riser blank is a piece of outer diameter from large to small, from the large end to the small end, which consists of the largest equal-diameter section (A section), the tapered section (B section), and the smaller The equal-diameter section (C section) and the smallest equal-diameter section (D section) are smoothly transitioned into a tubular member. The tapered standpipe of motorcycle steering column is usually processed by steel pipe, and the most traditional processing technology is forging, that is, firstly, the round steel pipe with equal diameter is heated up, and then the corresponding part of the steel pipe is forged into a con...

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Problems solved by technology

[0004] Compared with the traditional heating forging process, the methods used in the above two patents have significantly improved production efficiency, saved labor, and reduced manufacturing costs. The hole is deformed, so in the selection of the round tube blank, it is necessary to choose a raw material with a wall thickness greater than the wall thickness of the large end of the finished tapered riser. The wall thickness of the raw material should not be too large, because too thick is not conducive to the forming of the small end, so The strength of the big end of the finished conical riser is often low, and the big end is prone to cracks when the hole is reamed, which affects the qualified rate of the finished product

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