ANSI/AGMA 6101-F19 pdf free.American National Standard Design and Selection of Components for Enclosed Gear Drives (Metric Edition).
4 Design conditions
This standard should be used in conjunction with appropriate current AGMA standards. When the operating conditions are known, each component of the drive shall be designed to meet or exceed those conditions. When operating conditions are not known, all load carrying components of the drive shall be designed to support the stated mechanical rating of the drive for continuous duty based on a unity service factor (1.0). External loads shall be considered as acting in directions and rotations producing the most unfavorable stresses unless more specific information is available. Peak loads shall be accounted for in the design.
For enclosed drives designed to operate under specific conditions such as load, speed, duty cycle and life, components shall be selected accordingly.
4.1 Load spectrum analysis
It is recommended that the cumulative fatigue damage criteria proposed by Miner’s Rule similar to the method in ANSI/AG MA ISO 6336-6-A08 may be employed to evaluate the effects of variable loading on the life of components.
4.2 Momentary peak loads
This standard is based on an allowable momentary mechanical peak load rating of 200 percent (mechanical peak load rating multiplied by 2.0) for spur, helical, herringbone and bevel gear drives and an allowable momentary mechanical peak load rating of 300 percent (mechanical peak load rating multiplied by 3.0) for wormgear drives. Allowable momentary peak loads for a combination of gear types within one gear drive should be consistent through all the components of the gear drive, whether it is 200% or 300%. A limited number of peak stress cycles are allowed, typically less than 10 000 for spur, helical, herringbone, and bevel gear drives and 25 000 for wormgear drives.
Frequency and duration of overloads shall be considered when designing and selecting components. If the overload exceeds the allowable peak load rating and the frequency or duration of the overload becomes significant (greater than 100 cycles during the design life), the designer should consider a cumulative fatigue analysis such as Miner’s Rule.
If the overload exceeds the allowable peak load rating and the frequency or duration of the overload is less than 100 cycles during the design life, the conditions should be evaluated to assure that the yield strength of any component is not exceeded.
4.3 System analysis
This standard assumes that within the operating speed range, the system of connected rotating parts is compatible and free from critical speeds and torsional or other types of vibrations, no matter how induced.
The gear drive designer or manufacturer is not responsible for the system analysis unless this provision is clearly identified by contractual agreement.
5 Shafts
This clause covers a stress analysis procedure applicable to cylindrical steel shafts used in conjunction with, and as a part of, enclosed gear drives. This analysis may or may not be applicable to other materials or other types of machinery.
Shaft stress is but one consideration in the design of shafting. A shaft must have proper radial, axial, and torsional stiffness to limit deflections to acceptable levels and to avoid unwanted vibratory motion.
The equations and allowable stresses shown in Annex C have been accepted practice for shaft design that have been included in AGMA standards and used successfully for many years.
5.1 Design criteria
Shafts must pass two stress analysis tests to be considered adequately designed. First, they must be designed to resist fatigue failure due to cyclic loading over their intended life. All operating loads, including momentary peak loads, shall be considered and a Miner’s Rule analysis similar to the method in ANSI/AGMA ISO 6336-6-A08 may be required to properly account for the different stress states. See 5.6.8.ANSI/AGMA 6101 pdf download.