Optimum design of fit clearance of proportional cartridge valve

The fit clearance between the spool and the sleeve has important influences on the performance of the proportional cartridge valve. Too small clearance will cause jam and too much clearance will increase leakage. Therefore, under the precondition of no sticking, the smaller the clearance, the better the performance. The minimum fit clearance is affected by two factors, the machining accuracy and the structure deformation. The structure deformation is related to the working condition and the structure of valve. It is costly and takes much more time to optimize the fit clearance by the trial and error method. According to a specific working condition, the sleeve deformation of a proportional cartridge valve with an 80-mm port is evaluated by the three-dimensional finite element simulation. A series of experiments are carried out under the different fit clearances and the different pressures. The comparison between the simulation results and the experimental results shows that the sleeve deformation under pressure is the decisive factor to optimize the fit clearance of the proportional cartridge valve, and the finite element simulation accuracy can meet the engineering requirements for optimizing the fit clearance.