This part of ANSI/AGMA 2015 establishes an accuracy grade system relevant to tangential measurements on flanks of individual cylindrical involute gears.

It specifies definitions for gear tooth accuracy terms, the structure of the gear accuracy grade system, and allowable values.

It is strongly recommended that any user of this part of ANSI/AGMA 2015 be very familiar with the methods and procedures outlined in AGMA 915-1-A02. Use of techniques other than those of AGMA 915-1-A02 combined with the limits described in this part of ANSI/AGMA 2015 may not be suitable.

This standard provides the gear manufacturer and the gear buyer with a mutually advantageous reference for uniform tolerances. Ten accuracy grades are defined in this standard, numbered A2 through A11, in order of decreasing precision.

Equations for tolerances

Equations for tolerances and their ranges of validity are provided in 7.2 for the defined accuracy of gearing. In general, these tolerances cover the following ranges:

5 ≤ z ≤ 1000 or 10 000/mn whichever is less

5 mm≤ D ≤ 10 000 mm

0.5 ≤ mn ≤ 50

4 mm≤ b ≤ 1000 mm

β ≤ 45°

where

D is pitch diameter;

m_n is normal module;

b is facewidth (axial);

z is number of teeth;

β is helix angle.

See clause 4 for required and optional measuring methods.

Exceptions

This standard does not apply to enclosed gear unit assemblies, including speed reducers or increasers, gear motors, shaft mounted reducers, high speed units, or other enclosed gear units which are manufactured for a given power, speed, ratio or application.

Gear design is beyond the scope of this standard. The use of the accuracy grades for the determination of gear performance requires extensive experience with specific applications. Therefore, the users of this standard are cautioned against the direct application of tolerance values to a projected performance of unassembled (loose) gears when they are assembled. Refer to the latest AGMA Publications Index for applicable standards.

NOTE: Tolerance values for gears outside the limits stated in this standard should be established by determining the specific application requirements. This may require setting a tolerance smaller than calculated by the formulas in this standard.