The invention relates to the technical field of
pipe contracting machines, and discloses a straightening structure of a large
pipe contracting
machine and the large
pipe contracting
machine using the straightening structure. The straightening structure comprises a bottom plate, two adjusting assemblies, two supporting assemblies and a plurality of positioning assemblies; a first sliding groove, a second sliding groove, a third sliding groove and a fourth sliding groove are formed in the side face of the bottom plate, the two supporting assemblies are used for supporting the bottom plate, a straight-through hole is formed in the middle of the bottom plate and used for keeping away from a machined
pipe fitting, and the multiple positioning assemblies are arranged in the circumferential direction of the straight-through hole at equal intervals. The first sliding groove, the second sliding groove, the third sliding groove and the fourth sliding groove are formed in the periphery of the bottom plate and matched with the two active adjusting assemblies and the two elastic supporting assemblies, an adjusting matrix with the self-locking and dynamic balancing capacity is constructed, and the problem that in the
diameter reducing process of large pipes, due to the
dead weight or
machining deviation, the axial lead deviates is solved.