The invention relates to the technical field of engine crankshafts, and discloses a
crankshaft structure for a large-cylinder-
diameter engine, a
crankshaft comprises a main journal, a
crank arm and a
crank pin, a
crank pin circular bead is arranged at the crank pin, a main journal circular bead is arranged at the main journal, and the crank pin circular bead and the main journal circular bead are both arranged to be of a concave smooth circular bead structure. The
torsional vibration and the strength of the
crankshaft are improved; a crank arm of the crankshaft is connected with the balance block, a protrusion is arranged in the middle of the top face of the balance block, and the balance block and the crank arm are in
butt joint and fixed through the protrusion. By means of the inwards-concave type fillet structure, the specific crank arm thickness, the specific crank pin
diameter and the specific main journal
diameter, the use requirement for safety of an 8L2842 engine is met; the crankshaft
shock absorber end reduces
oil pressure fluctuation through the oil plug with the throttling hole, and the stability of the
shock absorber is improved. According to the
flywheel end, the
flange is used, the
machining difficulty of the main gear is simplified, the inverted-T-shaped balance block can concentrate
mass points on the outer circle, and the
mass of the balance block is reduced under the condition that balance is achieved.