Method of forming axles with internally thickened wall sections

Abstract

A method for forming a variable wall thickness axle or tube with internally thickened wall sections comprises extruding a tubular metal blank within an elongated die. An elongated punch pushes the blank through the die. The punch has an end abutting and pushing the blank into and through the die and an elongated portion which is spaced from the interior wall surface of the die. Movement of the punch in pushing the blank causes the blank to partially extrude forwardly through the die until stopped and then to extrude rearwardly around the punch elongated portion through the space for forming a tube. A tubular ring is then inserted within the extruded tube at a pre-determined location and is fixed in place to provide a thick, combined tube wall and ring wall, section which extends radially inwardly of the tube. A number of spaced-apart rings may be used to provide spaced-apart thickened wall sections within the tube. The rings may be pre-formed with variable wall thickness around their circumferences for varying the thicknesses of the combined wall sections around the circumference of the tube.