Tooth surface analysis method based on thermo-mechanical coupling and its application in prediction of gear dry-running bearing capacity

Abstract

In gear transmission, the continuous meshing of the teeth will lead to an increase in their temperature, which will have a certain impact on the working performance of the tooth surface. In order to explore the failure-bearing capacity of gears under dry-running conditions, temperature effects were considered in existing methods for determining tooth surface failure, making it more suitable for high-temperature working conditions caused by a lack of lubrication. The failure situation of gears within 35 min after losing lubrication was analyzed. The results indicate that when the gear loses lubrication, the tooth surface temperature of the gear pair has exceeded the material melting point after working at an input power of 2000 kW for 12 min. But when the power drops to 1000 kW, the instantaneous temperatures of the driving and driven gear tooth surfaces at the end of 35 min reach 1090 and 995°C, respectively, which are lower than the scuffing temperature of the tooth surface. The cumulative wear depths of the driving and driven gear tooth surfaces at the end of 35 min were 239 and 86.6 um, respectively, which were lower than the failure wear depth of the tooth surface; The allowable contact stress of the gear pair within 35 min is greater than its contact stress, meeting the judgment condition of no pitting failure. This indicates that reducing power can appropriately extend the failure time of gear teeth, thereby improving the ultimate working capacity of gears under dry-running conditions. In addition, a gear dry-running experiment was carried out. By comparing the theoretical calculation results with the measured gear failure degree, it shows that the improved method for determining gear surface failure is effective.