Study on the Fatigue Performance Test and Contact Strength of Automatic Transmission Gear with Coating

Abstract

The contact condition of gear surface can be improved by preparing the antifriction coating， and then strengthen the fatigue life of gear. The influence of antifriction coating on contact strength of gear is studied. Firstly， the antifriction coating is prepared on SRV standard specimen surface， the friction coefficients of coated specimens are obtained through friction-wear test. Then， the fatigue endurance tests are carried out for uncoated and coated automatic transmission gear in automotive transmission， the surface morphology characteristics of the gear are obtained by measuring. Lastly， an analysis model of contact strength on rough surface is established based on nonlinear elastic-plastic contact theory of gear. The effect of antifriction coating on improving the contact fatigue strength of gear is obtained. The results show that the manganese phosphate coating can improve the fatigue endurance life of gears by reducing the contact stress， the maximum contact stress of gear decreases first and then increases with the roughness， which provides theoretical guidance for strength designing of the coated gears.

Keywords

• Automotive gear