METHOD FOR MANUFACTURE OF VALVE SLEEVE

摘要

A hoolw cylindrical casing with one closed end is produced by forging. By means of a tapered punch and die pressing the upper part of the open end of the cylindrical casing is expanded outwards to form a conical opening. (2) The internal grooves are cut by means of a downward stroke of a broaching tool. Due to the tapered opening of the casing the cutting edges of the broaching tool engage and commence the cut to a short distance from the open end. The stroke of the broaching cutter is set to terminate the groove before reaching the closed end. (3) A cylindrical punch fitting in the grooved bore forces the casing through a circular die to straighten out the tapered upper section.