The sealing of the drive shaft assembly of the impact screw drilling tool is very easy to fail under the coupling of high temperature and 3-D compound motion,which limits the popularization and application of the impact screw drilling tool.In order to study the sealing characteristics and parameter sensitivity of the drive shaft assembly under the coupling effect of high temperature,high speed and reciprocating motion,the contact surface formed by the shaft and the slip ring was defined as the main sealing surface,and the contact surface formed by the O-ring and the groove bottom was defined as the secondary sealing surface.Based on the contact pressure of the main sealing surface,numerical simulation was performed on the relevant parameters that affect the sealing characteristics of the combined ring,and the influence of friction coefficient,O-ring diameter,carbon fiber content and reciprocating speed on the sealing performance of the combined ring was studied.Studies have shown that with the increase of friction coefficient,the contact pressure and Mises stress of the primary and secondary sealing surfaces in the pre-compression state increase,the contact pressure of the primary and secondary sealing surfaces in the static seal state decreases,and the Mises stress of the slip ring increases.In the dynamic seal state,when the friction coefficient of left and right stroke is 0.01,0.02,0.03,the contact pressure fluctuation range is small.When the friction coefficient is 0.04,the contact pressure fluctuation range is larger.It is reasonable to recommend that the friction coefficient is less than 0.04.As the diameter of the O-ring and the carbon fiber content increase,the contact pressure of the primary and secondary sealing surfaces and the Mises stress of the O-ring and slip ring in the pre-compression state increase,and the contact pressure and Mises stress of the primary and secondary sealing surfaces in the static and dynamic sealing states increase.With the increase of reciprocating speed,the average contact pressure of the primary and secondary sealing surfaces in the right stroke is larger than that in the left stroke.The contact pressure of the left stroke shows a decreasing trend;on the contrary,the average value of the contact pressure and the stress difference between the left and right strokes increase.The research results provide guidance and reference for the selection and use of sealing rings of impact screw drilling tools in the future.