Forging of Long-Stroke Crankshafts by the TR Method
SourceThe manufacture of long-stroke crankshafts lends itself to new methods of forging and equipment. Lately, at the Metal Forming Institute in Poznan, Poland, a very efficient method and the necessary equipment have been developed for single throws for semibuilt, shrink-fitted crankshafts. Furthermore, the method also is well-adapted for forging single crank throws carrying a half main journal on each side. The method enables the forging of single crank throws with the optimal shape of crank webs and with minimum weight. Thanks to a special design development, the horizontal upsetting force is about 2.5 times larger than the nominal press capacity. Such a very high-efficiency forging device permits the forging of large crank throws on a relatively small forging press. Furthermore, with a background of accumulated experience, a new forging method for fully forged, long-stroke crankshafts has been developed at the Metal Forming Institute. By this method, each crank arm is formed separately in new, specially designed forging equipment.