Electrohydraulic servo valve

Servo valves can provide precise control of position, velocity, pressure, and force with good post-movement damping characteristics.

The EHSVs in use during the 1940s were characterized by poor accuracy and slow response times due to the inability to rapidly convert electrical signals into hydraulic flows.

Single-stage servo valves suffer from limitations in flow capability and stability due to torque motor power requirements.

Typically, the valve will move the spool proportionnaly to an electrical signal that it receives, indirectly controlling flow rate.

For instance, some have internal feedback so that the input signal effectively control flow or output pressure, rather than spool position.

These valves are suitable for electrohydraulic position, velocity, pressure or force control systems with extremely high dynamic response requirements.

The twin Moog servo valves are used to deform the shape of the die on this blow molding accessory designed by BMC Controls Limited.