Concepts to Extend Servosystem Life and Minimize Performance Degradation

The search to improve the operational life of fluid power servosystems has led to a better understanding of the conditions which cause degradation of performance. A principal factor involved is the dimensional stability of the critical elements within the servovalve itself. A combination of the application of all-fluid techniques with that of superior materials offers promise. This paper discusses work accomplished in the application of tungsten-carbide to critical metering elements in a servovalve. Laboratory tests indicate an improvement of better than 50 times the life of conventional materials. The application of all-fluid techniques mitigates the critical nature of mechanical elements within the valve. A discussion of a closed loop all-fluid servo is presented.