The valve matching rig was developed to assist in the production, assembly and testing of aerospace servo valve spool and bushing assemblies.
The spool and bushing are fitted to generic tooling which simulates the servo valve assembly. The spool is attached to a stepper motor drive with linear encoder feedback which moves the spool within the bushing. At the same time the control software measures the flow and pressures across the valve and determines the position of the lands. From this a calculation is made to determine if the lands are in the correct position or if they need to be machined.
Normally these units consist of a spool operating in two bushings, one being the control ports and the other being the switch bypass mechanism.
Once the machining has been completed, a range of tests are carried out, such as general flow plots, leakage tests, pressure gain and spool transfer load.
The machine was initially developed to run one variant, but due to customer requirements it has now been expanded to run eight variants. This was made possible by the flexibility in the mechanical design and software structuring.