Producing method of wound muffler, and wound muffler

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.

1 . A producing method of a wound muffler formed by inserting a silencer into an inside of a main body formed in a cylindrical shape, the silencer including an expandable part expandable in an axial direction in at least one of an inlet pipe for exhaust gas and an outlet pipe for exhaust gas, the method comprising:
 inserting the silencer into the inside of the main body with the expandable part of the silencer contracted; and   expanding the expandable part of the silencer so as to extend a front end of the at least one of the inlet pipe and the outlet pipe including the expandable part to an outside of the main body.   
     
     
         2 . A wound muffler comprising:
 a main body being formed in a cylindrical shape, and   a silencer being inserted in an inside of the main body, the silencer including an expandable part expandable in an axial direction in at least one of an inlet pipe for exhaust gas and an outlet pipe for exhaust gas.   
     
     
         3 . The wound muffler according to claim wherein
 the expandable part includes mountain-folded portions and valley-folded portions, each mountain-folded portion to be a projecting portion if the expandable part is contracted, and each valley-folded portion to be a recessed portion if the expandable part is contracted, and   the mountain-folded portions and the valley-folded portions are alternately arranged in a direction along a circumferential direction and along the axial direction of the at least one of the inlet pipe and the outlet pipe including the expandable part.