Patent ID: 6907892

Claim:
An exhaust apparatus comprising an exhaust pressure adjusting unit for adjusting an opening area of an exhaust pipe variably, wherein: said exhaust pressure adjusting unit having: a switching valve, provided rotatably in said exhaust pipe, for varying an opening area of said exhaust pipe; a rotating shaft, extending from inside to outside of said exhaust pipe, for rotating said switching valve fixed thereon; a rotating shaft takeoff connection, provided in said exhaust pipe, for supporting a portion of said rotating shaft, said portion being located between an inner portion and an outer portion of said exhaust pipe; and gas introduction means for introducing purge gas into a gap between said rotating shaft takeoff connection and said rotating shaft, and wherein said gas introduction means includes a purge gas introduction hole provided in said rotating shaft such that one end portion of said hole faces an inner side of said exhaust pipe and another end portion of said hole faces an outer side of said exhaust pipe.