Anti-deformation inner rounding tool for thin-walled cylinder

The invention discloses an anti-deformation inner rounding tool for a thin-walled cylinder. Through mutual cooperation of a square head arranged on a supporting disc rotating rod and a square hole formed in the center of a supporting disc, circumferential movement of supporting circular beads arranged on the supporting disc in deep gradient grooves formed in inner molded faces of segmented arc supports is achieved; and through interaction of segmented arc support guiding frames and guiding grooves formed in the surfaces of the corresponding sides of the segmented arc supports, movement of thesegmented arc supports in the circumferential diameter direction is achieved. When the supporting circular beads rotate around inflection points of the deep gradient grooves formed in the inner moldedfaces of the segmented arc supports, the outer molded faces of the segmented arc supports are closely attached to inner molded face of the cylinder, the cylinder is rigidly rounded, enough rigidity is provided for the thin-wa