US Patent 7681426 Unitary rear axle housing and method for manufacturing same

A method for manufacturing a one piece axle tube housing with an integral spindle includes providing a tube blank, providing the blank with a region of increased thickness, inserting a mandrel having a reduced diameter profile, passing a reducing die over the tube to conform the tube to the shape of the mandrel; and extraction of the mandrel from the tube to cause outward deformation of the tube at specific locations. A further swaging step may be used to form the final spindle structure.