Abstract: Solenoid valve is complex heterogeneous system involving multi-physics coupling of mechanics, electronics, magnetics and thermo and so on, whose reliability and life depends largely on the heat generated during the operation. After analyzing the structure and principle of a hydraulic proportional solenoid valve in an automatic transmission, a multi-discipline coupled thermo-mechanics model for the solenoid valve is built up with the two-dimensional axial symmetric finite element method, and the temperature distribution and thermal deformation of the solenoid valve with different currents under two operating environments are simulated. The calculated results show that high temperature and stress caused by operating environment and current are important factors leading to thermal failure of solenoid valves, and furthermore there is a similar linear growth relationship, especially for those operating under the environment with bad heat emission condition, which would lead to much higher temperature and stress quickly and so reduce the life and reliability of the solenoid valve. By comparing the calculated results and the experiment data, the thermo-characteristic model is identified to be feasible with high precision, which is useful for the reliability design of solenoid valves.

Key words: solenoid valve;coupled multi-physics;finite element method;thermo-mechanics;failure mechanism