Analysis on Over-leakage of a Solenoid Valve

Aiming at the fault of over-leakage of a certain type solenoid valve, influence of the total leakage is studied based on the formula of annular gap flow. Firstly, internal leakage ways of the solenoid valve under the power-on and power-off conditions are analyzed. Secondly, factors affecting overlap of the key valve port are explored, including the axial dimension tolerance of the spool and the sleeve, and size of the compensating groove of the spool. Finally, improvement measures are obtained, including changing the axial dimension tolerance of valve rand from symmetrical tolerance (±0.1 mm) into positive tolerance (0, + 0.2 mm), and widening the distance between the control edge and the compensating groove. The improvement measures eliminated the fault of excessive leakage of solenoid valve.