a. Material, hardness and defects. The material of the gear does not meet the requirements; the main factor affecting the contact fatigue strength of the gear is the low hardness after heat treatment, which cannot ensure the contact fatigue strength of the gear as it should be. In addition, there are defects on the tooth surface or inside, which is also one of the reasons for insufficient contact fatigue strength.


b. Gear precision is poor. Gear processing and assembly accuracy does not meet the requirements, such as meshing accuracy, poor motion accuracy, etc. There is also too much error in the center distance of the housing of the circular gear.



c. Lubricant does not meet the requirements. The grade of the lubricant used is not correct, the viscosity of the oil is low, and the lubrication performance is poor.


d. Oil level is too high. The oil level is too high, the temperature of the oil rises, which reduces the viscosity of the lubricant, destroys the lubricating performance and reduces the working thickness of the oil film.