Therefore, a single reduction ratio has been chosen to demonstrate the general behavior of both standards which can be considered adequately representative of the multiple stage ratios. All of the subject gearing is single helical, carburized and symmetrically mounted between two bearings. The high speed shaft of the speed reducer is evaluated at 990 rpm for all six reducer sizes and both nominal ratios. I contains gear center distance, face width, and exact ratios corresponding to the two nominal ratios. Before gear ratings can be calculated a gear quality level comparison is required to determine what AGMA quality level corresponds to the equivalent ISO quality level.
Quality level establishes allowable manufacturing limits of gear tooth profile, pitch, and lead.
Profile, is the curve forming the side of the tooth section. Pitch, is the distance from one point on a tooth to the same point on the adjacent tooth. Lead, is the axial advance of the helix for one revolution. Detailed definitions of these gear tooth attributes can be found in AGMA standard 390.03, Gear Classification, Materials and Measuring Methods for Unassembled Gears. The sample gearing is manufactured to an AGMA quality level Q-10.