Improving the position control performance of a Proportional spool valve, using a 3D CFD modeling

摘要

It is well known that the valve internal geometry, meaning the spool and cores design, can heavily affect a hydraulic valve performance in terms of pressure drop characteristic as well as axial flow forces or spin effects on the spool. The last two interact directly with the position control performance of a direct actuating closed loop control valve, reducing in the worst cases its capability. Based on a proportional 4 way 3 position closed loop control spool valve for basically industrial application, with pressure up to 320 bar and standard flow-rate up to 180 l/min, this paper shows as a tridimensional fluid-dynamic software can help engineers to develop the best core geometry, to minimize the spool spin behavior, reducing the prototyping requirement and finally the time-to-market lead time and development cost. A first core geometry has been evaluated and studied to tune the mathematical model and to validate it comparing its results with the experimental data. Then, the same approach has been applied to investigate several different geometries to define the best one in order to minimize spool spin behavior while maintaining a good pressure drop characteristic. A limited number of solutions have been prototyped and tested to verify the mathematical model predictions. The final result is a lower spin effect on the spool, that reduces the closed loop control effort, with better overall component performance.