Patent ID: 6129332
Filing Date: 2000-10-10
Classification: F02M

Abstract:
A hydraulic control valve comprising(a) a valve housing having an axis and defining(1) a valve chamber having first and second axially spaced valve seats having identical diameters;(2) a control cylinder;(3) first and second end cylinders; said valve chamber, said control cylinder and said first and second end cylinders being axially arranged in a series and forming a cavity; said first and second end cylinders together flanking said valve chamber and said control cylinder;(4) a first pressure conduit communicating with said valve chamber;(5) a second pressure conduit communicating with said first end cylinder;(6) a third pressure conduit communicating with said second end cylinder;(7) a control conduit communicating with said control cylinder; and(8) a discharge conduit communicating with said valve chamber;(b) a plunger body accommodated for axial displacements in said cavity and being composed of separate plunger body segments having at least two different geometrical shapes and being loosely axially serially disposed in an end-to-end relationship; said separate plunger body segments including(1) a valve body disposed in said valve chamber for selectively assuming a seated position in said first and second valve seats and for controlling communication between said discharge conduit and said first pressure conduit through said valve chamber;(2) a control piston disposed in said control cylinder;(3) a first support piston disposed in said first end cylinder and exposed to pressure from said second pressure conduit; and(4) a second support piston disposed in said second end cylinder and exposed to pressure from said third pressure conduit; said first and second support pistons having identical diameters; the pressures supplied by said second and third pressure conduits to said first and second end cylinders form means for urging together said valve body segments into a unitary structure for movement as a one-piece component; and(c) a closing spring supporting said second support piston and urging said valve body towards one of said valve seats.