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A fluid control valve apparatus comprises logic valve means including a valve housing, a first valve member defined in the valve housing, and an axially movable valve body arranged in the first valve chamber, with the valve body including opposite end portions and a conical surface portion brought i

A fluid control valve apparatus comprises logic valve means including a valve housing, a first valve member defined in the valve housing, and an axially movable valve body arranged in the first valve chamber, with the valve body including opposite end portions and a conical surface portion brought into contact with the conical surface portion when the valve body is moved in a valve closing direction. First and second hydraulic fluid chambers are defined in the valve housing and communicate with each other when the conical surface portion is out of contact with the valve seat and out of communication when the conical surface portion contacts the valve seat. A first pilot chamber in the valve housing, adjacent one end portion of the valve body, biases the valve body in a closing direction by a first pilot pressure signal. A second valve chamber is defined in the valve housing with an extension of the valve body being formed by extending the other end portion of the valve body through the first hydraulic fluid chamber, and is arranged in the second valve chamber for axial movement. An independent second pilot chamber biases the valve body in an opening direction by a second pilot pressure signal.

대표청구항 ▼

A fluid control valve apparatus including: logic valve means comprising: a valve housing; a first substantially circular valve chamber defined in the valve housing; a valve body arranged in the first valve chamber for fluidtight movement in an axial direction, the valve body including opposite end p

A fluid control valve apparatus including: logic valve means comprising: a valve housing; a first substantially circular valve chamber defined in the valve housing; a valve body arranged in the first valve chamber for fluidtight movement in an axial direction, the valve body including opposite end portions and a conical surface portion; a substantially circular valve seat adapted to be brought into fluidtight sealing contact with the conical surface portion of the valve body when the valve body moves in a valve closing direction; a first hydraulic fluid chamber and a second hydraulic fluid chamber defined in the valve housing and adapted to be brought into communication with each other when the conical surface portion of the valve body is released from contact with the valve seat and brought out of communication with each other when the conical surface portion of the valve body is brought into contact with the valve seat; and a first pilot chamber defined in the valve housing adjacent one end portion of the valve body and operative to force the valve body to move in the valve closing direction by a first pilot pressure signal received therein; wherein the logic valve means further comprises: a second substantially circular valve chamber defined in the valve housing; a valve body extension formed by extending the other end portion of the valve body through the first hydraulic fluid chamber and arranged in the second valve chamber for fluidtight movement in an axial direction; and a second pilot chamber defined in the valve housing adjacent an end of the valve body extension and operative to force the valve body extension to move in a valve opening direction by a second pilot pressure signal received therein; said first valve chamber, said second valve chamber and said valve seat being of such diameter that when the conical surface portion of the valve body is brought into contact with the valve seat to bring said first and second hydraulic fluid chambers out of communication with each other, the fluid pressures acting on the valve body in each of said first and second hydraulic fluid chambers are balanced so as to apply no net force in an axial direction of said valve body; said first valve chamber being defined by an inner peripheral surface of a sleeve fitted in said valve housing, said one end portion of the valve body being disposed in said inner peripheral surface of the sleeve for sealing movement in an axial direction; said conical surface portion of the valve body having a portion of the maximum diameter positioned in said second hydraulic fluid chamber, said sleeve having an outer diameter larger than a maximum diameter of the conical surface portion and an inner diameter less than the maximum diameter whereby the valve body can be inserted into and withdrawn out of the valve housing in an axial direction with the sleeve being removed therefrom upon assembly and disassembly of the valve means; and wherein said valve body has a peripheral wall portion defining a pressure regulating chamber positioned between said opposite end portions, and a communicating duct formed therein and communicating said pressure regulating chamber with said first hydraulic fluid chamber, said second valve chamber having a diameter less than the diameter of the valve seat and said peripheral wall portion being configured such that a cross-sectional area thereof is substantially equal to a difference between the square of the diameter of the valve seat and a square of the diameter of the second valve chamber multiplied by p