AUTOMOBILE MOUNTING PIPE MANUFACTURE METHOD

摘要

A method of manufacturing a mounting pipe for automobile is provided to simplify the manufacturing process, and reduce the manufacturing cost and accomplish quality uniformity of the mounting pipe accordingly by manufacturing a mounting pipe through a simple process capable of forming the mounting pipe using a former only and completing the manufacture of the mounting pipe without additional machining of inner diameter of the mounting pipe. A method of manufacturing a mounting pipe for automobile comprises: an upsetting process of reducing length of a cut workpiece(1) and expand diameter of the workpiece; a preforming process of forming a preliminary groove(2) to a shallow depth on front and rear faces of the workpiece; a simultaneous backward extruding process of extruding the workpiece to form a pipe part(4) by forming a groove(3) on one side face of the workpiece and form a groove(5) having a depth shallower than that of the groove(3) on the other side face of the workpiece at the same time; a piercing process of for forming a complete pipe form by piercing a part of the workpiece between the groove of the onside face and the groove of the other side face; a forward extruding process of contracting outer diameter and inner diameter of one side of the workpiece to form a contraction part(6) and an inclined part(7); and an upsetting process of completing manufacturing of a mounting pipe for automobile by simultaneously forming a step height(8) and forming a diameter expanding part(9) in the contraction part by upsetting.