| 摘要 |
A hydraulic control valve includes a valve housing defining a valve chamber having first and second axially spaced valve seats of identical diameters, a control cylinder and first and second end cylinders. The valve chamber, the control cylinder and the first and second end cylinders are axially arranged in a series and form a cavity. A first pressure conduit communicates with the control cylinder, a second pressure conduit communicates with the first end cylinder, a third pressure conduit communicates with the second end cylinder; a control conduit communicates with control cylinder; and a discharge conduit communicates with the valve chamber. A plunger body is accommodated in the cavity and is composed of a valve body disposed in the valve chamber for being selectively seated in the valve seats, a control piston disposed in the control cylinder, a first support piston disposed in the first end cylinder and exposed to pressure from the second pressure conduit and a second support piston disposed in the second end cylinder and exposed to pressure from the third pressure conduit. The valve body, the control piston and the first and second support pistons constitute loosely axially serially disposed separate plunger body segments having different geometrical shapes dependent on functions thereof. A closing spring supports the second support piston and urges the valve body towards one of the valve seats.
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