Patent ID: 6942838

Claim:
Parts in an exhaust system comprising: an inner pipe formed from a cylindrical pipe, containing a catalyst carrier in a center portion and having substantially taper-like reduced diameter portions integrally formed in both end portions of the center portion; and an outer pipe formed from a cylindrical pipe, having substantially taper-like reduced diameter portions integrally formed in both end portions of a center portion fitted on the center portion of said inner pipe and provided on an outer periphery of the inner pipe in such a manner as to have a gap between the outer pipe and said inner pipe all along an area including the reduced diameter portions in both end portions, wherein the reduced diameter portions in both end portions of said outer pipe are formed with cylindrical portions at front portions of said reduced diameter portions in accordance with a spinning process, and an inner surface of said front end portion thereof is closely attached to an outer surface of the inner pipe or an interposed material.