Based on the tests of friction characteristics

the equivalent radius of curvature situated in meshing point and the principle of power loss equivalent to frictional work

the experimental principles

qualifications and conclusions from simulated specimens analyzed comparatively.The advantages of dynamic measurement of teeth surface friction coefficients are researched.Based on the test experience and research result

FEM and technology of computational inverse study are applied

then the inverse study method of key friction coefficients based on "calculation-test aggregative model" is raised.The calculation method is a new idea to solve the friction coefficient under complex lubrication conditions.Exactly research friction coefficient is useful for studying on the gear friction principle and reducing the level of decrease noise and vibration of gear.