ÖNORM ISO 17485

This International Standard establishes a classification system that can be used to communicate geometrical accuracy specifications of unassembled bevel gears, hypoid gears, and gear pairs. It defines gear tooth accuracy terms and specifies the structure of the gear accuracy grade system and allowable values. This International Standard provides the gear manufacturer and the gear buyer with a mutually advantageous reference for uniform tolerances. Ten accuracy grades are defined, numbered 2 to 11 in order of decreasing precision. This International 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 manufactured for a given power, speed, ratio or application. Gear design is beyond the scope of this International Standard. The use of the accuracy grades for the determination of gear performance requires extensive experience with specific applications. Therefore, the users of this International Standard are cautioned against the direct application of tolerance values to a projected performance of unassembled (loose) gears when they are assembled. Tolerance values for gears outside the limits stated in this International Standard will need to be established by determining the specific application requirements.