To manufacture an exhaust system part for an automobile at low cost by performing spinning with high productivity while preventing increase of a processing time caused by a processing amount limitation per one path to improve production efficiency when forming a diameter-reduced portion at a pipe end of a metal pipe body containing an inner insertion material such as a catalyst carrier, a filter and a silencing material, and while inhibiting occurrence of wrinkle or a crack at the pipe end.
When forming a cone portion and a connection portion by performing diameter-reduction processing while pressing processing rollers against an end of a metal pipe body containing an inner insertion material such as a catalyst carrier, the processing rollers are not reciprocated axially beyond the end of the metal pipe body to be processed and are reciprocated while being turned back in front of the pipe end to form a flare-shaped projection at the pipe end. By performing spinning while eccentrically arranging a pipe axis of the metal pipe body to be processed and a revolution axis of the processing rollers, an eccentric exhaust system part for an automobile can be manufactured at low cost.
NISHIO KATSUHIDE
KUROBE ATSUSHI
NOBATA YASUHIRO
TOYOTA MOTOR CORP