To provide a manufacturing method of a winding bush capable of effectively using a lengthy material and simple in manufacturing process at the time of manufacturing the winding bush excellent in performance improved in rigidity by welding an abutting surface.
A lengthy material 10 is cut in a cutting process to sequentially cut it without producing blank chips by providing a small clearance δ between a dice 3 and a punch 4. Consequently, a strip piece 11 on which a rolled-over recessed part 22 is formed is provided. Thereafter, the strip piece 11 is curved and transferred to a curving molding process to mold it in a cylindrical shape. Continuously, it is connected to the inside of the rolled-over recessed part 22 by electronic beam welding so that height of a welding mark stays in this rolled-over recessed part 22. At this time, a return projected piece 23 formed in the cutting process is melted and disappears, and a winding bush not requiring to carry out cutting-down treatment of the welding mark is manufactured.
KAWAMURA KUNIHIKO
SHIBAYAMA TAKAYUKI
