Machine shaft for crane

The utility model relates to the technical field of machine shafts, in particular to a machine shaft for a crane, which comprises a shaft body and a part main body, a mounting hole matched with the shaft body is arranged on the part main body, shaft shoulders are arranged on the shaft body and on two sides of the part main body, and the shaft shoulders and the part main body are arranged at intervals. An upper limiting piece and a lower limiting piece are arranged on the shaft body between the shaft shoulder and the part body, one side of the upper limiting piece and one side of the lower limiting piece abut against the shaft shoulder, the other side of the upper limiting piece and the other side of the lower limiting piece abut against the side wall of the part body, and the upper limiting piece and the lower limiting piece are of symmetrical semi-arc structures. The upper limiting piece and the lower limiting piece are arranged on the shaft shoulder and matched with each other to wrap the outer surface of t