Speed reducer shell structure for reducing radiation noise of drive axle

The invention provides a speed reducer shell structure for reducing radiation noise of a drive axle. The speed reducer shell structure comprises a flange body, driven bevel gear containing bodies, a bearing seat supporting body, a drive bevel gear bearing supporting body and a differential bearing supporting body which are mutually connected into an integral body, and is characterized in that eight reinforcing ribs are arranged on the outer surface of the shell; the reinforcing ribs fully extend from the peripheral edge of the bearing seat supporting body onto the edge of the flange body; five reinforcing ribs are parallelly arranged, wherein two pairs of reinforcing ribs are in the same plane; and the other three reinforcing ribs are scattered and extend onto the flange body in the circumferential direction with the bearing seat supporting body adopted as the center, and form certain angles with the former five reinforcing ribs. According to the speed reducer shell structure, the parallel ribs and the scatte