Method for manufacturing a vehicle muffler

A method for manufacturing a sound-absorbing tubular body comprising:

• applying a binder to one surface of a nonwoven fabric composed of inorganic fibers each being in a filament form;
• then rolling up the nonwoven fabric into a tubular shape with the surface having the binder applied thereto facing inward;
• infiltrating additional binder into an outer peripheral surface of the nonwoven fabric rolled up into the tubular shape;
• and
• heating the nonwoven fabric infiltrated with the binder to a predetermined temperature to harden the binder.

A method for manufacturing a vehicle muffler comprising:

• forming a pair of half bodies from a nonwoven fabric composed of inorganic fibers each being in a filament form;
• attaching the half bodies in an abutting state to an outer periphery of an inner pipe so as to cover or surround a peripheral surface of the inner pipe, to obtain a tubular body serving as a sound-absorbing material;
• and
• surrounding the tubular body with an outer pipe to constitute the vehicle muffler.

A method for manufacturing each of a pair of half bodies, the pair of half bodies being configured to be attached, in an abutting state, to an outer periphery of an inner pipe of an inner-outer double pipe constituting a vehicle muffler so as to cover the inner pipe, to constitute a tubular body serving as a sound-absorbing material, the method comprising:

• applying a binder to one surface of a first nonwoven fabric composed of inorganic fibers each being in a filament form;
• placing the first nonwoven fabric on an inner surface of an upwardly-open container-shaped jig such that the one surface having the binder applied thereto faces upward and the first nonwoven fabric forms a recessed shape;
• rolling up a plurality of second nonwoven fabrics composed of inorganic fibers each being in a filament form;
• inserting the second, rolled-up nonwoven fabrics into the recessed space formed by the first nonwoven fabric;
• wrapping ends of the first nonwoven fabric around the second, rolled-up nonwoven fabrics disposed in the recessed shape formed by the first nonwoven fabric;
• and
• then closing the container-shaped jig and heating the container-shaped jig to a predetermined temperature to harden the binder.