To propose a method for forming an unequal-wall-thickness tube which can form an unequal-wall-thickness tube with a partly thin-walled circumferential portion, from a cylindrical mother tube with a nearly equal wall thickness, a method for manufacturing an automotive wheel rim formed from the unequal-wall-thickness tube, and a device for forming the unequal-wall-thickness tube.
The device for forming the unequal-wall-thickness tube is provided with a plurality of pressing rolls 20a-20f which respectively have, on their circumferential faces, pressing protrusions 22a-22f which increasingly widen the partly thin-walled circumferential portion. The cylindrical mother tube x fitted loosely into a mandrel roll 2 is rotated by the rotation of the mandrel roll 2. Each of the pressing protrusions 22a-22f is pressed against the rotating tube x in a stepwise manner according to the widening sequence so as to form the partly thin-walled circumferential portion y1-y6. The invention relates to the method for forming the unequal-wall-thickness tube X having the thin-walled circumferential portion Y of a prescribed width, the method for manufacturing the wheel rim using the process of forming the unequal-wall-thickness tube X, and the device 1 embodying the forming method. The invention enables wheel rims of unequal wall thicknesses to be manufactured, while such productivity as in manufacturing ordinary wheel rims is retained.
NOJIMA KATSUHIRO
NAGATA KUNIO
NAKANO HIROYUKI
NAGATA AKIHIRO
| JPH0734960B2 | 1995-04-19 | |||
| JPH0891005A | 1996-04-09 |
Yasutoshi Iwata