STEUER- BZW. REGELVENTIL

摘要

A control valve having a rotor for communicating outlet port or ports selectively to fluid drain port or to inlet port so as to change flow direction of fluid to be supplied to fluid operated apparatus. The control valve comprises first and second pistons inserted in a hollow space of the rotor and a compression spring arranged between the pistons. At the operation position(s) of the rotor or the valve, the first piston which is biased by the compression spring oscillatingly blocks and reopens fluid passage formed within the rotor outside the first piston for communicating the inlet port to the outlet port(s) under the influence of the compression spring and fluid pressure of the outlet port(s) from which fluid is constantly drained with a small rate through the valve. Fluid pressure of the outlet port may be varied by varying the force of the compression spring by an advance of the second piston. Consequently, by controlling the advance of the second piston, fluid pressure of the outlet port(s), namely fluid pressure applied to the fluid operated apparatus may be controlled. The control valve thus functions not only as a change-over valve but as a valve for controlling fluid pressure applied to fluid operated apparatus.