Self-centering fixture with double conical wedges

The utility model provides a self-centering fixture with double conical wedges. The self-centering fixture comprises a mandrel connected to a machine tool via a flange, and is characterized in that a pull rod is arranged in a cavity of the mandrel, one side, close to the flange, of the pull rod is connected with a piston of a hydraulic cylinder, a fixed conical surface is formed on the mandrel along the outer circumference of the mandrel, a movable conical core sleeves the pull rod, a retaining sleeve sleeves the portion, between the fixed conical surface and the movable conical core, of the pull rod, a front wedge matched with the fixed conical surface is arranged at the front end of the retaining sleeve, a rear wedge matched with the movable conical core is arranged at the rear end of the retaining sleeve, and a connecting disk sleeves the portion, on the outer side of the movable conical core, of the pull rod and is fixed on the pull rod via a plurality of nuts. The self-centering fixture with the double conical wedges has the advantages that the self-centering fixture is capable of positioning radially through an inner hole of a cylinder jacket, and accordingly, clamping is stable, assembly and disassembly of workpieces are facilitated, stress of the cylinder jacket in all directions is uniform, and machining precision is high.