Rotary flow-path exchanging valve

DETAILED DESCRIPTION An object of the present invention is to provide a rotary-flow path exchanging valve which can maintain the necessary strength of the stopper pipe made of a normal material when it is heated to be soldered to the valve seat plate and can satisfy the endurance performance of the stopper pipe with no increase in cost.
In order to attain the above object, there is provided a rotary flow-path exchanging valve comprising: a cylindrical valve housing; a valve seat plate having a low pressure side port secured to said valve housing and connected with a low pressure side conduit, a high pressure side port connected to a high pressure side conduit and an exchanging port; a valve element rotatably provided within the cylindrical valve housing; the valve element being in contact with the valve seat plate in its one end surface so that the exchanging port is selectively communicated with either one of the low pressure side port and the high pressure side port by rotation between a first rotary position and a second rotary position, the valve element having a high pressure communicating groove for communicating said high pressure side port with the exchanging port and a low pressure communicating groove for communicating the low pressure side port with the exchanging port; an electromagnetic solenoid for rotating the valve element; a hard stopper pipe secured to either one of the high pressure side port and the low pressure side port and protruding into the high pressure communicating groove or said low pressure side communicating groove, the stopper pipe abutting on different side walls apart from each other of the high pressure side communicating groove or the low pressure side communicating groove in a rotary direction of said valve element to limit a rotation range of the valve element between the first rotary position and the rotary position (Claim 1).
There is also provided a method for installing a stopper pipe for the rotary flow-path exchanging valve of the above flow-exchange valve comprising the steps: securing the stopper pipe to either one of the high pressure side port and the low pressure side port; and hardening the stopper pipe by plastic deformation (Claim 5)