This standard establishes a classification system
which may be used to communicate geometrical
accuracy specifications of unassembled bevel gear-
ing. It provides a designation system for accuracy of
bevel gears and gear pairs. It also provides
information on measuring methods and practices.
This standard provides the gear manufacturer and
the gear buyer with a mutually advantageous
reference for uniform tolerances. Eight accuracy
grades are defined in this standard, numbered B3
through B10, in order of decreasing precision.
1.1 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:
0.2 ≤ mmn ≤ 50
5 ≤ z ≤ 400
5 mm ≤ dT ≤ 2000 mm
where
dT is tolerance diameter (see 3.2);
mmn is mean normal module;
z is number of teeth.
See clause 4 for required and optional measuring
methods.
1.2 Tolerance tables
Tolerance tables are provided in annex D for those
who prefer to use tables rather than computations for
the values of the tolerances that define the accuracy
of gearing. These tables are calculated from the
equations in 7.2.
1.3 Measuring methods and practices
Measuring methods and practices are included to
promote uniform measurement procedures (see
clause 5). Thesemethods permit the user to conduct
measuring procedures which are accurate and
repeatable to a degree compatible with the specified
accuracy. Experienced personnel, with calibrated
instruments in suitable surroundings, are required.
1.4 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 perfor-
mance 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 deter-
mining the specific application requirements. Thismay
require setting a tolerance smaller than calculated by
the formulas in this standard.
AGMA 2009-B01-2001 history
2001AGMA 2009-B01-2001 Bevel Gear Classification, Tolerances, and Measuring Methods Errata: October 2001