Crankshaft is an eccentric shaft made from casting alloy steel. Herringbone gear ring, connection rod and bearing are mounted on it. The gear ring is herringbone when assembly, the herringbone gear ring and the crankshaft are of interference fit and fastened with bolts and nuts. Big end of connection rod is mounted on three eccentric straps of the crankshaft via single row cylindrical roller bearing. Small end is mounted on crosshead pin via double row long cylindrical roller bearing. Double row radial spherical roller bearings are Mounted at either end of the crankshaft.