To provide a method for manufacturing highly accurate reinforcing ring for run-flat tires at a low cost and with high productivity.
A die 6 having a forming plane on the inner side and a plurality of grooves 3-5 for forming beads formed in the forming plane along the circumferential direction is arranged on the outer circumferential side of a tubular material ring 1 made of an aluminum alloy and a coil body 7 for electromagnetic forming is arranged on the side of the inner circumferential side of the tubular ring 1. In such a state, a large instantaneous current is fed to the coil body 7 for electromagnetic forming, the tubular material ring 1 is enlarged in diameter and pressed against the forming plane of the die 6, thus, performing electromagnetic forming into a shape corresponding to the forming plane. The reinforcing ring 17 consisting of parallel parts 12, 13 at both ends and beads 14-16 which are swelled to the side of the outside diameter along the circumferential direction between the parallel parts is obtained.
EGUCHI NORITAKA
SAKURAI TAKEO
TANIMOTO HIROSHI
