2. Tooth surface meshing

For high-speed and heavy-load gear transmission, due to the large friction between the tooth surfaces and the high relative speed, the temperature of the meshing area is too high. Once the lubrication conditions are poor, the oil film between the tooth surfaces will disappear, making the metal of the two gear teeth. The surfaces are in direct contact so that mutual bonding occurs. When the two tooth surfaces continue to move relative to each other, the harder tooth surface will tear off part of the material on the softer tooth surface along the sliding direction to form grooves.

3. Fatigue pitting

When the two gear teeth meshing with each other are in contact, the action force and reaction force between the tooth surfaces cause contact stress on the two working surfaces. Since the position of the meshing point changes and the gear moves periodically, the contact stress is According to the pulse cycle change. Under the action of this alternating contact stress on the tooth surface for a long time, small cracks will appear at the tool marks of the tooth surface. As time goes on, the cracks gradually expand laterally on the surface layer. The surface of the tooth produces a small area of ​​spalling to form some fatigue pits.

4. Broken gear teeth

Gears under load in operation engineering are like cantilever beams. When the periodic stress of pulses at the root exceeds the fatigue limit of the gear material, cracks will occur at the root and gradually expand. When the remaining part cannot bear the transmission load, it will occur. Broken teeth. Gears may also be broken due to severe impact, eccentric load and uneven material during work.

5. Plastic deformation of tooth surface

Under the impact load or heavy load, the tooth surface is prone to local plastic deformation, so that the curved surface of the involute tooth profile is deformed.