RELEASE MANDREL FOR CORRECTING DEFORMATION OF HOLE OF PRECISION THIN-WALLED LONG-LENGTH PIPES IN THE PROCESS OF EXTERNAL PROCESSING Russian patent published in 2021 - IPC B23B31/40 

FIELD: pipe making.

SUBSTANCE: mandrel is designed to correct the deformation of a hole of a precision long-length pipe-billet of large diameter during the external alternate processing of sections of the pipe-billet on a lathe, and it contains case 1 with a central hole, in which cone 2 with thread 3, mated to a threaded hole in a case wall, is located with the possibility of rotation and axial movement, and the other end of the cone is mated by groove 24 with rod 4 passing through a hole in spindle 5 of the lathe. In radial guides of the case, made perpendicular to the cone axis and evenly around the circumference, there are spring-loaded sectors 7 resting on the cone, outer ends 9 of which have a segmented cylindrical shape, and cylindrical surfaces of segments are made according to a size of a diameter of the hole of pipe-billet 19. The working length of the cylindrical surface of the mandrel is determined by a given ratio, depending on the length of processed sections of the pipe-billet. The diameter of the mandrel at the divorced position of sectors 7 is made equal to the algebraic sum of the nominal diameter of the hole of the billet and half of the tolerance for this size. The described diameter of the mandrel with sectors reduced to its axis is made 1…3 mm smaller than the smallest possible cross-sectional size of the hole deformed during processing. Cylindrical surfaces 9 of sectors that are in contact with the hole of the pipe-billet can be made of anti-friction and less rigid material relatively to material of the pipe-billet. Rod 4 can be provided from the outside with rod pipe 10, the inner end of which is fixed to the end of branch pipe 11, and at the end of it protruding from the spindle of the lathe, there are flats 28 for a wrench. On fixed mounting bolts 13 in a gap between a nozzle flange and the end face of hub 12 of mandrel case 1, sets of disc springs 14 can be installed with a certain tension, and at an outlet of spindle 5, detachable polyurethane sleeve 17 with an outer cone can be installed and fixed to the rod pipe, while the top of cone is wound into an annular gap between the spindle hole and the outer diameter of the rod pipe. The inner end of rod 4, coupled to groove 24 of the mandrel cone, can be located in rod pipe 10 with gap 15. A long dimension from the outer end to the mandrel can be applied to the outer surface of the rod pipe with the necessary discreteness. The rod pipe and the rod can be made composite in the form of sections 18, each of which contains segments of rod 4 and rod pipe 10 identical in length, and on the outer surface of the rod pipe, there are an ordinal number, the size from the outer end to the mandrel and flats 28 for the wrench.

EFFECT: increase in the processing accuracy is achieved in terms of different thickness and cylindrical nature of precision thin-walled long-length pipes, including large diameter ones.

6 cl, 5 dwg