Control valve device

Claim 1

A control valve device for controlling the flow of exhaust gas which flows from an exhaust pipe of an engine to an intake pipe thereof, thereby to reduce harmful components of the exhaust gas emitted from the engine comprising: a valve member having a passage therein connected with both the exhaust pipe and the intake pipe for passing the exhaust gas therethrough, a valve seat formed in the passage, a cup member, a pair of inner and outer bellows which are made of stainless steel, each being fixed to the inner surface of the cup member at one end thereof and each being fixed to the valve member at the other end thereof with a preselected distance remaining between a lower skirt portion of said cup member and the valve member to restrict excessive crumpling action of said bellows, a passage means provided in the cup member opening to a chamber enclosed by the bellows, the cup member, and the valve member for actuating the bellows according to an external pressure signal applied to the chamber therethrough, a valve stem having one end which is fixed to said cup member, said stem being installed through the inner part of the inner bellows and guided by the valve member, a valve body fixed to the other end of the valve stem for being seated on the valve seat by only a resilient expanding force of the bellows when the external pressure signal is not applied, whereby the flow of the exhaust gas is controlled according to the external pressure signal applied to the chamber.