OPTIMAL DESIGN OF FAST SWITCHING VALVES IN DIGITAL DISPLACEMENT MACHINE

The digital displacement(DD) machine is a highefficiency intelligent hydraulic machine. The DD machine works in three modes which is controlled by the working sequence of the fast switching valve. The fast switching valve used in DD machine requires both less switching time and power loss. The dynamic model and control method of the DD machine is built assuming the loss of the DD machine occurs in the valve switching only. Then, the efficiency map with the normalized switching time and flow coefficient is drawn to get the requirements for the valve. For a type of poppet valve, the fluid field of the valve is optimized based on the angle of sleeve and the radius of the optimal spool. Using the computer fluid design(CFD) instead of the real experiments, it's easy to get a optimal field geometry of the valve in the set of valve parameters. Finally a fast switching valve is manufactured according to the selected optimized parameters of the valve.