Miniaturized hydraulic valve, and applications thereof in robot systems

An electrohydraulic valve comprising:

• a valve manifold having an inlet port and an outlet port;
• a valve housing having a common chamber defined therein, a metering port in communication with the common chamber, and a first end coupled to the valve manifold;
• a first nozzle in fluid communication with the inlet port, the first nozzle having a first nozzle tip portion disposed within the common chamber, the first nozzle tip portion including a first orifice;
• a second nozzle in fluid communication with the outlet port, the second nozzle having a second nozzle tip portion disposed within the common chamber, the second nozzle tip portion including a second orifice;
• a first valve plug disposed within the common chamber and positioned in opposing relation to the first orifice;
• a first valve actuator coupled to the first valve plug and operable to move the first valve plug between a closed position in which the first valve plug contacts the first nozzle tip portion and closes the first orifice and an open position in which the first valve plug is offset from the first nozzle tip portion and a first gap is created between the first valve plug and the first orifice for passage of fluid from the first orifice to the common chamber;
• a second valve plug disposed within the common chamber and positioned in opposing relation to the second orifice;
• a second valve actuator coupled to the second valve plug and operable to move the second valve plug between a closed position in which the second valve plug contacts the second nozzle tip portion and closes the second orifice and an open position in which the second valve plug is offset from the second nozzle tip portion and a second gap is created between the second valve plug and the second orifice for passage of fluid from the common chamber to the second orifice;
• and
• a first stroke adjustment coupled to the first valve plug and operable to adjust a position of the first valve plug relative to the first nozzle tip portion, wherein the first stroke adjustment comprises a first adjustment head coupled to the first valve plug and a first adjusting screw threadedly coupled to the first adjustment head, wherein rotation of the first adjusting screw causes translation of the first adjustment head along the first adjusting screw;
• and
• wherein the first valve actuator comprises a first piezo actuator having a first piezo element and a first flexure element, and wherein the first flexure element is coupled at a first end to the first valve plug and at a second end to the first adjustment head.