Cold hammering manner null of collar attaching

摘要

PURPOSE: To make the metal flow in a housing continuation by forming a columnar blank to an intermediate blank having a circular flange part and opening holes at both end parts, successively pressing a bottom part in the opening hole direction at the reverse flange part side and forming to the cupped housing with the flange. ;CONSTITUTION: The round bar material having the almost same diameter as the diameter (except the flange part 11) of the housing W2 with the flange part is cut off to the necessary length and the necessary volume of the columnar blank W0 is prepared. In a first process, the columnar blank W0 is formed to the intermediate blank W1 providing the circular flange part 11 on the outer periphery at one side of end part and the bottom part 12 in the inner periphery at the intermediate part in the axial direction and having the opening holes 13, 14 at both ends by closed forging with a punch and upper and lower dies. In a second process, the bottom part 12 in the intermediate blank W1 is pressed in the opening hole direction at the reverse flange part with the punch to form this blank to the cupped housing W2 with the flange. By this method, the good product having high quality with continuation of the metal flow is obtd. and as this formation is executed by cold forging, the yield is good.;COPYRIGHT: (C)1994,JPO