Patent ID: 7367303

Claim:
A crankshaft of an in-line four-cylinder engine, the engine being provided with a cylinder block having bearings, wherein a flywheel is attached to one end of the crankshaft in an axial direction, the crankshaft comprising: five journals each supported by one of the bearings; four crankpins each corresponding to one of the cylinders of the engine; and eight arms alternately coupling the five journals and the four crankpins, each arm being provided with a counterweight, wherein the arm that is closest to the flywheel has a greater average thickness in a direction of the rotation axis of the crankshaft than those of the other arms, and wherein two of the arms that are coupled to both sides of the third journal from the flywheel each have a center of gravity closer to its own counterweight compared to the centers of gravity of the arms that face said two arms with the corresponding crankpins in between.