| 摘要 |
<p>A change-over valve comprising: a valve housing 3 having a valve cylinder 2 which provides with an input port 19 constructed by an annular groove in central portion on said valve cylinder, an input passage 7 communicated with said input port 19, a pair of output ports 17 and 23 constructed by annular grooves besides said input port 19 and a pair of output passages 4 and 8 communicated with said output ports 17 and 23, respectively, and a pair of drain ports 16 and 25 disposed on the opposite ends of said valve cylinder 2; and a spool 18 slidably housed in said valve cylinder 2 and having an annular groove 20 disposed in the central portion on said spool 18 and a pair of small diameter portions on the opposite ends of said spool 18; characterized in that a closing valve 10 is disposed in an internal passage of said spool 18 for connecting and disconnecting one of output ports 23 to a drain port 25 adjacent thereto on a valve cylinder 2 and; ther is provided an actuator for opening said closing valve 10 against a spring force by fluid pressure of the other of said output ports 17.</p> |
