The failure form of gear teeth

1.Pitting on tooth surface

Most of the pitting occurred on the root surface near the pitch line.

Tooth surface pitting is one of the main forms of tooth failure in well lubricated closed gear drive.

The pitting resistance of tooth surface is mainly related to the hardness of tooth surface.

Improving the hardness of the tooth surface, reducing the surface roughness of the tooth surface and increasing the viscosity of the lubricating oil are conducive to preventing pitting.

2.Tooth surface wear

Tooth surface wear is one of the main failure modes of open gear transmission which has poor lubrication conditions and is easy to be attacked by dust and its harmful substances.

In order to reduce the wear of tooth surface, the closed drive with good lubrication condition should be adopted as far as possible. At the same time, the hardness of tooth surface should be increased and the surface roughness of gear tooth surface should be reduced.

3.Gluing of tooth surface

Measures such as increasing the hardness of the tooth surface, reducing the surface roughness of the tooth surface, and selecting different materials (small affinity) for the two gears can reduce the occurrence of gluing.

4.Broken teeth

Fatigue fracture and overload fracture

Tooth fracture is one of the main forms of tooth failure in open gear drive and hard face closed gear drive.

Preventive measures: select appropriate modulus and tooth width, use appropriate materials and heat treatment methods to reduce the stress concentration of tooth root, and the fillet of tooth root should not be too small, and there should be a certain required surface roughness, so that the maximum bending stress at the dangerous section of tooth root does not exceed the allowable stress value.

5.Plastic deformation of tooth surface

It is beneficial to prevent or reduce the plastic deformation of the tooth surface by increasing the hardness of the tooth surface and using lubricating oil with high viscosity.

[Conclusion]

  1. Type and characteristics of gear transmission.
  2. Involute properties and meshing characteristics of involute gears.
  3. Names, basic parameters, geometric dimension calculation and correct Meshing Conditions of all parts of the involute standard spur gear.
  4. The tooth shape characteristics and correct Meshing Conditions of helical cylindrical gear and straight bevel gear.
  5. Characteristics of rack and pinion drive.
  6. Failure form, failure reason and preventive measures of gear.
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