Modules for spur gears
Modules for spur gearsISO 54 (JIS B 1701-2:2017)Standard values of the normal module for spur and helical gears. Two tables are listed, one for 1 mm and above and one for below 1 mm.Modules for straight bevel gearsISO 678 (JIS B 1706-2:1999)Standard values of the module and the diametral pitch for straight bevel gears. Standard values below 1 mm are listed as well.
For 1 mm and over
Unit mm
Notea) Best avoided where possible.
For under 1 mm
Unit mm
Notes
- References
- JIS B 1701-2:2017 Cylindrical gears — Involute gear tooth profile — Part 2: Modules
- Standard normal modules for involute spur and helical gears in general and heavy machinery. They do not apply to automotive gears.
- The standard values below 1 mm (the second table) are specific to Japan. They were set from a survey of practice in Japan and are not in the corresponding international standard (ISO 54:1996).
- When to use series I and when to use series II is explained behind the i in the table header.
- The module is the pitch of the basic rack in the normal section, divided by pi. On a helical gear the normal module and the transverse module differ; on a spur gear they are the same.
