METHOD AND DEVICE FOR MOLDING UNEVEN WALL THICKNESS TUBE

摘要

A method of molding an uneven wall thickness tube capable of molding an uneven wall thickness tube having a partially thin-walled peripheral part from a cylindrical raw tube with approximately uneven wall thickness, a method of manufacturing a wheel rim for a vehicle molded from the uneven wall thickness tube, and an uneven wall thickness tube molding device. In the method of molding the uneven wall thickness tube, the uneven wall thickness tube (X) having the thin-walled peripheral part (Y) of a prescribed width is molded by loosely fitting a plurality of pressing rolls (20a) to (20f) having pressing projected parts (22a) to (22f) increased in width stepwise formed on all the periphery thereof to a mandrel roll (2) in the order of increasing in width and pressing the pressing projected parts (22a) to (22f) against the rotating cylindrical raw tube (x) to form thin-walled peripheral parts (y1) to (y6) stepwise. The method of manufacturing the wheel rim comprises a step for molding the uneven wall thickness tube (X). The device (1) materializes the molding method. Thus, the wheel rim with uneven wall thickness can be manufactured while the productivity of normal wheel rims is maintained.