Servovalve

A servovalve comprising:

• a fluid transfer valve assembly comprising a housing having channel therethrough fluidly connecting a supply port, a return port and a control port formed in the housing;
• a moveable valve spool located within the channel that regulates flow of fluid between the supply port, the return port and the control port in response to a control signal, wherein the moveable valve spool comprises a first spool part and a second spool part;
• and
• a drive assembly that moves the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow, the drive assembly comprising:
• a piezoelectric actuator positioned between the first and the second spool parts within the channel, the piezoelectric actuator comprising a first piezoelectric actuator element having a first end around which the first spool part is mounted and a second piezoelectric actuator element having a first end around which the second spool part is mounted, and each of the first and the second piezoelectric actuator elements having a second end, the second ends of the first and second piezoelectric actuator elements being connected to each other
• wherein application of the control signal to the piezoelectric actuator causes extension or contraction of the first and second piezoelectric actuator elements according to the polarity of the signal applied to each of the elements and causes corresponding movement of the respective spool parts;
• a first nozzle fluidly connecting the supply port and the channel of the housing;
• and
• a second nozzle fluidly connecting the return port and the channel of the housing, wherein expansion and contraction of the first and second piezoelectric actuator elements axial moves the respective first and second spool parts relative to the first and second nozzles to cover or expose the respective nozzles;
• wherein the second end of the first piezoelectric actuator element is attached to the second end of the second piezoelectric actuator element by means of a connector element;
• wherein the connector element is connected to an adjustment plate that is configured to can be moved relative to the ends of the housing to establish a neutral position of the spool parts.