scope:

This information sheet describes many of theways in which gear teeth can fail and recommends methods for reducing gear failures. It provides basic guidance for those attempting to analyze gear failures. The information sheet should be used in conjunction with ANSI/AGMA 1010--E95 in which the gear tooth failure modes are defined. Similar definitions can also be found in ISO 10825. They are described in detail to help investigators understand failures and investigate remedies.

The information presented in this document applies to spur and helical gears. However, with some exceptions the information also applies to bevel, worm and hypoid gears. Discussion of material properties is primarily restricted to steel.

System investigations

Gear system dynamic problems are beyond the scope of this information sheet. However, it is important to recognize that many gear failures are influenced by problems with the gear system, such as high loads caused by vibration. When investigating gear failures, it is necessary to consider that the cause may stem from a problem with the system rather than the gears.

Analysis by specialists

It is not the intent of this information sheet to discuss the details of disciplines such as dynamics, material science, corrosion or tribology. It is hoped that the material presented will facilitate communication in the investigation of gear problems.