Three-jaw chuck for self-centering numerical-control pipe intersecting cutting machine

The utility model discloses a three-jaw chuck for a self-centering numerical-control pipe intersecting cutting machine. The novel technical scheme includes that the three-jaw chuck mainly comprises a chuck body and a rear cover; a cavity is enclosed by the chuck body and the rear cover, a disc-shaped gear is positioned in the cavity, tapered teeth are axially uniformly distributed on a cylindrical surface of the chuck body, the disc-shaped gear is fixed into the cavity of the chuck body by the aid of the tapered teeth, guide grooves are formed in the upper surface of the chuck body, sliders are mounted in the guide grooves, and jaws are arranged on the sliders and are fixed by the aid of fastening bolts. The three-jaw chuck has the advantages that Archimedes spiral grooves are formed in the surface, which is in contact with the sliders, of the disc-shaped gear, threads are arranged on the sliders, accordingly, the three jaws can simultaneously radially move when a bevel pinion rotates by the aid of a wrench, workpieces can be automatically centered and clamped, and the three-jaw chuck is applicable to clamping the workpieces in the shapes of circles or regular triangles or regular hexagons or the like.