The wear of tooth surface is caused by metal particles, dust and sand entering into the working surface of tooth.
Uneven tooth surface and poor lubrication are also the causes of tooth surface wear.
In addition, misalignment, coupling wear and torsional resonance will cause greater torque change at the gear engagement point, or increase the impact, which will accelerate the wear.
After the gear is worn, the thickness of the gear becomes thinner, the profile of the gear is deformed, and the side clearance becomes larger, which will increase the dynamic load of the gear, not only increase the vibration and noise, but also possibly lead to the broken teeth.
The scuffing (scratch) of tooth surface is caused by the rupture of oil film when the meshing tooth surface is sliding relative to each other, and the tooth surface is in direct contact. Under the action of friction and pressure, the contact area will generate instantaneous high temperature, and the metal surface will be damaged by local fusion welding adhesion and peeling.
Scuffing often occurs under the conditions of too low viscosity of lubricating oil, too high operating temperature, too large load per unit area on the tooth surface, too high relative sliding speed, too small contact area, too low rotation speed (oil can not be brought up), etc.
When the gear surface is glued, it will accelerate the wear of the gear surface and make the gear transmission tend to failure quickly.