Advances in the Survival Life Research of Aerospace Gear Transmission Systems under Dry Running Conditions

In the field of aerospace, loss of lubricant and resulting lack of oil pose a major threat to gear transmission systems. In such cases, gear scuffing failure becomes the primary factor affecting the service life of aerospace gears. According to research conducted domestically and internationally, this study first analyzes the thermoelastic flow lubrication model of gears and related lubrication characteristics under dry running based on the theoretical framework of thermo-elastohydrodynamic lubrication (TEHL) theory. Subsequently, the distribution characteristics of the temperature field of the gear pair in a dry running state are systematically examined, and three key aspects are investigated, including boundary conditions, the steady-state temperature field, and the transient temperature field. After that, the fatigue life prediction of gear transmission under dry running conditions is summarized from two perspectives: gear bonding assessment and bonding failure time, and the methods for improving the dry running capability of gears are comprehensively explained. Furthermore, current techniques for enhancing gear performance under dry running conditions are systematically reviewed. Finally, the research progress on the service life of gear transmissions under dry running conditions is discussed.