High-strength machine shaft for crane

The high-strength machine shaft for the crane comprises a main shaft, a vertically-through main shaft hole is formed in the center of the main shaft, containing grooves with the diameter larger than that of the main shaft hole are formed in the top end and the bottom of the inner side wall of the main shaft, and reinforcing shafts matched with the containing grooves are arranged on the upper side and the lower side of the main shaft. Reinforcing ribs are circumferentially distributed on the peripheral face of the side, exposed out of the main shaft, of the reinforcing shaft, a first shaft hole penetrating up and down is formed in the center of the reinforcing shaft, a sub-shaft matched with the first shaft hole is inserted into the side, away from the main shaft, of the interior of the first shaft hole, and a plurality of reinforcing strips arranged up and down are circumferentially distributed on the outer side wall of the main shaft. The reinforcing strips are arranged on the outer side of the main shaft, t