Overall composite mechanical spiral type bulging device for car drive axle

The invention relates to an overall composite mechanical spiral type bulging device for a car drive axle. The bulging device comprises a bulging inner die, a bulging outer die and two thrust hydraulic cylinders, wherein the bulging inner die comprises an upper die block and a lower die block, and an auxiliary pressure device is arranged between the upper die block and the lower die block. Two ends of the upper die block and the lower die block are respectively hinged with the piston rods of the two thrust hydraulic cylinders through link mechanisms. The link mechanisms comprise hinge mounts, and the hinge mounts are hinged with the upper die block and the lower die block through connecting rods. A spin screw mechanism is arranged between the two hinge mounts and comprises a screw, one end of the screw is installed on one hinge mount, and the other end of the screw is installed a spiral base arranged on the other hinge mount. The screw and the spiral base mutually rotate under the action of force, and the length of the screw is automatically regulated. The bulging outer die comprises a support mechanism positioned on the transitional surface of an axle shell pipa bag. The piston rods of the two thrust hydraulic cylinders are oppositely arranged, and a quick-detached connecting structure is arranged on the piston rod of one thrust hydraulic cylinder.