| 摘要 |
In order to easily and inexpensively produce parts in an exhaust system in which a gap is formed in series to both of taper-like reduced diameter portions of inner and outer pipes, in the parts in the exhaust system having an inner pipe containing a catalyst carrier in a center portion and having substantially taper-like reduced diameter portions formed in both end portions of the center portion, and an outer pipe having substantially taper-like reduced diameter portions integrally formed in both end portions of a center portion corresponding to the center portion of the inner pipe and provided on an outer periphery of the inner pipe in such a manner as to have a gap all along the area including the reduced diameter portions in both end portions and the center portion, the reduced diameter portions in both end portions of the outer pipe are formed in accordance with a spinning process. Further, in order to produce the parts in the exhaust system, a producing method includes a step of fitting an outer pipe on an outer side of an inner pipe containing a catalyst carrier in a center portion and having substantially taper-like reduced diameter portions formed in both end portions of the center portion with holding a gap therebetween, and a step of applying a spinning process in such a manner as to have a gap between both end portions of the outer pipe and the reduced diameter portion in the inner pipe so as to reduce both end portions of the outer pipe in a substantially taper shape. <IMAGE>
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