The oil leakage under too high temperature which occurred in the course of shock absorber’s work process is not only a key problem which troubled the reliability design of the shock absorber, but also one of important factors to affect the vehicle ride. To investigate the influence rules of thermo-physical properties of the shock absorber on its reliability design, the transmission model of heat transfer rate and physical heat-transfer model of the twin-tube hydraulic gas-charged shock absorber was built and the equations of heat conduction, heat convection, as well as radiation heat transfer were derived, furthermore its thermodynamic model was established by the first law of thermodynamics. The temperature and the work time when the shock absorber had reached the thermal equilibrium were calculated by iterative algorithm, and the effects of thermo-physical properties on its temperature rising were analyzed innovatively, moreover the associated sensitivity analysis was carried on it finally. The simulation results show that four kinds of thermo-physical properties of the shock absorber affect its temperature rising characteristics. The references, which are used to enhance the reliability design of the shock absorber, can be provided from the analysis conclusions.
