Directional control hydraulic valve and system including same

A directional control hydraulic valve, comprising:

• a first valve configured to control a flow of a fluid flowing thereinto from a first input port, by being interlocked with a solenoid valve that is switched to an excited (on) state or non-excited (off) state;
• and
• a second valve connected to the first valve and configured to control a flow of the fluid flowing thereinto from the first valve, by a fluid flowing thereinto from a second input port or a third input port,
• wherein at least a part of the fluid having been passed through the first valve is discharged through a first output port and then flows into the second input port or the third input port, and
• wherein the first valve comprises:
• a first plunger configured to be displaced by the fluid flowing thereto from the first input port or by the solenoid valve;
• a first piston configured to be displaced by the fluid flowing thereto from the first input port or by restoring force of a first elastic body;
• a first body configured to be displaced by the first plunger and the first piston and to determine the flow of the fluid flowing thereinto from the first input port according to an amount of displacement thereof;
• and
• a first seat configured to be brought into contact with the first body as the first body is displaced, thereby determining the amount of displacement of the first body.

A directional control hydraulic valve, comprising:

• a first valve configured to control a flow of a fluid flowing thereinto from a first input port, by being interlocked with a solenoid valve that is switched to an excited (on) state or non-excited (off) state;
• and
• a second valve connected to the first valve and configured to control a flow of the fluid flowing thereinto from the first valve, by a fluid flowing thereinto from a second input port or a third input port,
• wherein at least a part of the fluid having been passed through the first valve is discharged through a first output port and then flows into the second input port or the third input port, and
• wherein the second valve comprises:
• a second plunger configured to be displaced by the fluid flowing thereto from the first input port;
• a second piston configured to be displaced by the fluid flowing thereto from the second input port or by restoring force of a second elastic body;
• a third piston configured to be displaced by the fluid flowing thereto from the third input port or by restoring force of a third elastic body;
• a second body configured to be displaced by at least one of the second plunger, the second piston, and the third piston and to determine a flow of the fluid flowing thereinto from the first valve according to an amount of displacement thereof;
• and
• a second seat configured to be brought into contact with the second body as the second body is displaced, thereby determining the amount of displacement of the second body.