Servovalve actuation

A deflector jet servovalve comprising:

• a deflector jet servovalve assembly (100) comprising:
• a header (112),
• an amplifier having an amplifier segment (144) defining an amplifier segment bore in flow communication with an inlet (1020), a first control port (1006), and a second control port (1008),
• a multilayered piezoelectric actuator (130) having a first end and a second end, the first end of the piezoelectric actuator (130) being mounted to the header (112), and
• a flow guide (132) mounted at the second end of the piezoelectric actuator (130), wherein the flow guide (132) is arranged for movement within the amplifier segment bore and includes a flow orifice (140) to direct flow from the inlet (1020) to the first control port (1006) and the second control port (1008), and
• a main stage valve (1000) comprising a spool (1002),
• wherein the first control port (1006) is in fluid communication with a first end of the spool and the second control port (1008) is in fluid communication with a second end of the spool such that movement of the spool is controlled by pressures within the amplifier segment,
• wherein the deflector jet servovalve assembly further comprises a feedback member (136) extending from the flow guide (132) away from the piezoelectric actuator (130), the feedback member configured to be driven by the spool (1002) of the main stage valve (1000),
• the piezoelectric actuator is mounted to the header (112) at a first point (A),
• The flow guide is mounted to the piezoelectric actuator at a second point (B),
• the feedback member attached to the spool of the main stage valve at a third point (C), and
• the first point (A) is located between the second point (B) and the third point (C) in a direction perpendicular to an axis of movement of the spool.

A piezoelectric actuator device for a deflector jet servovalve having an inlet (1020) defining an inlet flow direction, the piezoelectric actuator device comprising:

• a piezoelectric actuator (130) extending along a longitudinal axis, the piezoelectric actuator (130) having a first end;
• and
• a flow guide (132) extending from the first end of the piezoelectric actuator (130), the flow guide comprising a base portion integral with the flow guide, the base portion extending into the piezoelectric actuator;
• wherein the longitudinal axis of the piezoelectric actuator is perpendicular to the inlet flow direction defined by the inlet (1020);
• wherein the flow guide (132) includes a flow orifice (140) through which pressurized fluid from the inlet (1020) flows.

A method of manufacture of a deflector jet servovalve comprising the steps of:

• providing a flow guide having an integral base portion extending therefrom,
• forming an integral actuator/flow guide (132a) by depositing piezoelectric material onto the flow guide to form a piezoelectric actuator extending along a longitudinal axis;
• providing a header (112);
• providing an amplifier having an amplifier segment (144) defining an inlet (1020), a first control port (1006), and a second control port (1008), wherein the inlet (1020) defines an inlet flow direction;
• and
• mounting the integral actuator/flow guide (132a) to the header (112) such that the flow guide is positioned within the amplifier segment to direct flow from the inlet (1020) to the first and second control ports (1006, 1008);
• wherein the longitudinal axis of the piezoelectric actuator is perpendicular to the inlet flow direction defined by the inlet (1020);
• wherein the integral actuator/flow guide (132a) includes a flow orifice (140) through which pressurized fluid from the inlet (1020) flows to the first control port (1006) and the second control port (1008).