Abstract: A manufacturing method for a muffler includes: a trimming step, of cutting out a dogleg shaped muffler body member; a bending processing step of processing the muffler body member into a tube by advancing the muffler body member between an upper roller and a lower roller of a bending machine while adjusting an advancing direction with a guide and by changing a relative position of the upper roller and the lower roller; a first joining step of joining two ends of the tubularly-processed muffler body member in a long side direction; an insertion step of inserting an inner structural member into the inside of the tubularly-processed muffler body member; a second joining step of joining caps to opening portions of the tubularly-processed muffler body member; and a third joining step of joining an air intake joint and an exhaust pipe to the sealed muffler body member.

Abstract: A muffler is a wound muffler formed by inserting a silencer into an inside of a main body formed in a cylindrical shape, the silencer includes an expandable part expandable in an axial direction in an outlet pipe for exhaust gas, and after the silencer is inserted into the inside of the main body with the expandable part of the silencer contracted, the expandable part of the silencer is so expanded as to extend a downstream end of the outlet pipe to an outside of the main body.

Abstract: A manufacturing method for a muffler includes: a trimming step, of cutting out a dogleg shaped muffler body member; a bending processing step of processing the muffler body member into a tube by advancing the muffler body member between an upper roller and a lower roller of a bending machine while adjusting an advancing direction with a guide and by changing a relative position of the upper roller and the lower roller; a first joining step of joining two ends of the tubularly-processed muffler body member in a long side direction; an insertion step of inserting an inner structural member into the inside of the tubularly-processed muffler body member; a second joining step of joining caps to opening portions of the tubularly-processed muffler body member; and a third joining step of joining an air intake joint and an exhaust pipe to the sealed muffler body member.