Process for forming integral spindle-axle tubes

Abstract

A process for cold forming integral spindle-axle tubes includes placing a tubular blank within an open ended die having an extrusion die throat, and pushing the blank through the die throat with a punch. The punch is formed with a ram portion that applies pressure to the blank for moving it axially through the throat. The punch also has an extension closely fitted within the blank so that as the punch pushes the tube axially, the blank is extruded between the die throat and the extension to form a thin wall tube. After the blank is partially extruded, the punch is removed and a second blank is inserted. This second blank is then located between the punch ram portion and the trailing end of the first blank so that further movement of the punch causes the second blank to push the first blank through the die throat. At that time, a second punch extension, of smaller diameter than the first one, is arranged within the throat so that an inwardly thickened ring-like annular section is extruded within the extruded tube, at a distance from the trailing end of the tube. The die movement continues until the first extension is aligned within the throat and the trailing end portion of the extruded tube is completed. Thereafter, the steps are repeated to form additional extruded tubes. Each extruded tube has its trailing end portion and thickened ring section swaged radially inwardly first, until its outside diameter is less than the outside diameter of the tube, and secondly, until the inside diameter of the thinner wall trailing end portion is formed to the same internal diameter as that of the thickened section to thereby provide the integral spindle-axle tube.