Used but in excellent condition.
  • Series Designation SM4 – Servovalve, high performance, four-way
  • Valve Size 20 – 22,2 mm (0.875 in) port circle
  • Flow Rating At 70 bar (1000 psi) ∆p P A B T. (15) 57 15.0 US gpm 57 l/m
Eaton Vickers® SM4-20 servo valves can provide system closed loop control with exact positional accuracy, repeatable velocity profiles, and predictable force or torque regulation.
Typical applications include plastic injection molding and blow molding systems, test and simulation equipment, die casting machines, hydraulic press brakes, animation and entertainment equipment, oil exploration vehicles, and lumber machinery.
This model of the high performance SM4 series offers a wide range of rated flows from 3,8 to 76 l/min (1.0 to 20 USgpm) at ∆p of 70 bar (1000 psi).
The SM4 is a two-stage, modular design, flow control valve which can be manifold or subplate mounted. The symmetrical, dual coil, quad air gap torque motor is integrally mounted to the first stage nozzle flapper pilot valve with six screws. The second stage utilizes a four-way sliding spool and sleeve arrangement with a mechanical null adjust. Spool position is fed back to the first stage by means of a cantilever spring. An integral 35 micron (absolute) filter reduces sensitivity to contamination of the first stage.
An SM4 servo valve, when used with a hydraulic cylinder, position transducer, and appropriate electronics, can provide infinite cylinder position control to within 0,025 mm (0.001 in) or better, depending on the components selected, length of stroke, and load characteristics.
When applied with servo hydraulic motors using tachometer feedback and appropriate electronics, the SM4 provides infinite proportional flow control for real-time velocity/acceleration profiles. The resulting closed loop system can be error corrected to within one-tenth of a revolution per minute. With appropriate pressure transducers or load cells in force control applications, the SM4 makes possible exact load pressure/ force control. In addition, excellent system stability with pressure and load to ±1% full scale can be achieved.
The field-proven design of the SM4-20 servo valve, combined with Eaton Vickers® precision manufacturing techniques, provides you with the optimum in system control.