Polishing device for automobile driving shaft

The invention relates to the technical field of polishing devices, and discloses a polishing device for an automobile driving shaft. A mounting plate is fixed to the upper portion of the right side of a polishing bin, a first motor is fixed to the right side of the front face of the mounting plate, a cam is coaxially fixed to a rotor of the first motor, and a limiting cavity is fixed to the left side of the front face of the mounting plate; an extrusion plate is arranged on the right side of an inner cavity of the limiting cavity, and a connecting rod is fixed to the center of the left side of the extrusion plate. An additionally-arranged first motor drives a cam to rotate, when the protrusion of the cam makes contact with an extrusion plate, a movable rod drives a sliding block to move, a top plate can also move along with the cam, when the plane of the cam faces the extrusion plate, the extrusion plate can be reset under the extrusion force of a telescopic spring, the top plate is reset, and the cam rotates