Minimum recommended backlash values for gears based on the standards for AGMA, DIN and ISO. Backlash values are a reccomendation, It is important to understand what goes into deciding a backlash value, the standards are very helpful and are required reading.
Minimum recommended backlash from ANSI/AGMA 2002-B88 standard.
Backlash = 0.06 + 0.0005 × centerDistance + 0.03 × module
DIN backlash is based on the reference diameter and the application. It uses tables 1 and 2 from DIN 3967 to determine the tooth thinning and then normal backlash value must be calculated from them. The reference tooth thinning values are proposed by Niemann.
| Application | Recommended backlash (Niemann) |
|---|---|
| Casted rims | a29, a30 |
| Rims (normal backlash) | a28 |
| Rims (tight backlash) | bc26 |
| Turbo gears (high temperatures) | ab25 |
| Polymer machines | c25, cd25 |
| Locomotive gear trains | cd25 |
| Standard mechanical engineering, heavy machinery, not reversing | b26 |
| Standard mechanical engineering, heavy machinery, reversing | c25, c24, cd25, cd24, d25, d24, e25, e24 |
| Automobiles | d26 |
| Agricultural vehicles | e27, e28 |
| Machine tools | f24, f25 |
| Printing machines | f24, g24 |
| Measuring gearboxes | g22 |
Minimum backlash requirements from ISO TR 10064-2:1996 for ferrous gears in ferrous housings.
Backlash = (2/3) × (0.06 × module + 0.0005 × centerDistance + 0.03 × module)