抄録
Bearing strength of gears needs to be evaluated by considering various failure modes observed on tooth surface. In tempered gears, the load capacity is limited by pitting failure. To avoid pitting failure, we have come to make surface treatment such as carbulizing and nitriding for gear materials, which increases traction transfer capacity of gears significantly. Accordingly, failures such as spolling, scuffing and tooth breakage have come to occur instead of pitting. However, in practice micro-pitting and flaking take place, different from the well-known failure modes. Especially, when we test the gears with flaking occurred, we find that the gear tooth has a high probability of failure. Therefore, we observe the flaking process in gears with an optical microscope.
