A Comparison of Current AGMA, ISO and API Gear Rating Methods

摘要

There are many different gear rating methods in use today, and they can give substantially different results for any given gearset. This paper will make it easy to understand the choices and the impact the choices have on gearbox design. Eight standards are included - AGMA 2001; AGMA 6011; AGMA 6013; ISO 6336; API 613; API 617; API 672; and API 677. A brief introduction and history of each standard is presented, and the basic differences between them are highlighted. Two sets of examples are used to illustrate the differences. These examples are presented in both tabular and graphical format, and are fully discussed. The first set contains a wide range of gears, and each gearset is rated by each standard. The second set compares gears designed for a specific set of requirements according to each of these standards. The perils of increasing service factor are mentioned, particularly in regard to high pitch line velocity gears. Finally, there is a discussion of how to make a gearbox more reliable without changing the rating method or service factor. The choice of rating method can have a huge impact on the size of the gearbox, and this paper should help avoid specifying the wrong standard and having an oversized gearbox. It should also be useful as an aid to customers who are unsure of the differences between the standards.