ANSI/AGMA 2001-D04 pdf free.American National Standard – Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth.
Where applicable AGMA application standards exist, they should be used in preference to this standard. Consult AGMA Headquarters for current list of applicable standards. Where no applicable AGMA application standard exists, numerical values may be estimated for the factors in the general formulas, and the approximate pitting resistance and bending strength ratings calculated.
3.2 ImplIed accuracy
Where empirical values for rating factors are given by curves, curve fitting equations are provided to facilitate computer programming. The constants and coefficients used in curve fitting often have significant digits in excess of those inferred by the reliability of the empirical data. Experimental data from actual gear unit measurements are seldom repeatable within a plus or minus 10 percent band. Calculated gear ratings are intended to be conservative, but the scatter in actual results may exceed 20 percent.
3.3 Testing
The preferred method to predict overall system pertorniance is to test a proposed new design. Where sufficient experience is available from similar designs, satisfactory results can be obtained by extrapolation of previous tests or field data.
3.4 Manufacturing quality
Rating factors should be evaluated on the basis of the expected variation of component parts in the production run. The formulas of this standard are only valid for appropriate material quality and geometric quality that conforms to the manufacturing tolerances. Defects such as surface cracks, grinding temper, or tooth root steps may invalidate calculations of pitting resistance and bending strength.
3.4.1 Geometric quality
The rating formulas of this standard are only valid if the gear tooth and gear element support accuracies assumed in the calculations are actually achieved in manufacture (see clause 8).
Gear tooth accuracy considerations include: involute profile, tooth alignment (lead), tooth spacing and tooth finish.
Gear element support considerations include: gear case bore alignment, bearing eccentricities and shaft runouts.
3.4.2 Metallurgy
The allowable stress numbers, ac and included herein are a function of melting, casting, forging and heat treating practice. Hardness, tensile strength, microstructure and cleanliness are some criteria for determining allowable stress numbers. Allowable stress numbers in this standard are based on iO cycles, 99 percent reliability and unidirectional loading.
The allowable stresses are only valid for materials and conditions listed in this standard (see clause 16).ANSI/AGMA 2001 pdf download.