CAUTION NOTICE: AGMA technical publications are subject to constant improvement, ANSI/AGMA D04, Fundamental Rating Factors and Calculation. Credit line should read: “Extracted from ANSI/AGMA. Standard D04 or -D04 Fundamental Rating Factors and Calculation Methods for Involute Spur. Citations should read: See ANSI/AGMA D04, Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear.
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The intent of the AGMA strength rating amga is to determine the load which can be transmitted for the design life of the gear drive without causing root fillet cracking. The use of this standard at bending stress aga above those permissible for cycles requires careful analysis. Wear in low speed applications may be tolerable.
Method B is used for this calculation. The influence factors are normally used as modifiers to either a calculated stress from part configuration and applied load or to an allowable stress number based on material properties. The ratings of both pinion and gear teeth must be calculated to evaluate differences in geometry factors, number of load cycles, and material properties.
New Refinements to the Use of AGMA Load Reversal and Reliability Factors
In such cases, the cumulative fatigue effect of the duty cycle is considered in rating the gear set. SCOPE Rating formulas This standard provides a method by which different 2101–d04 designs can be theoretically rated and compared. For a case hardened gear, the analysis of allowable yield properties should include a 2101-x04 calculation through a cross section of the material.
In others where profile and motion transmission accuracies are not critical, this may be acceptable for limited life. The effects of webs or stiffeners can be an improvement but are not accounted for.
Moore machines similar to Figure 1. There are many possible sources of overload which should be considered. Even if the input torque and speed are constant, significant vibration of the gear masses, and therefore dynamic tooth forces, can exist. It is not the intent of this standard that all requirements for quality grades be certified, but that practices and procedures be established for their compliance on a production basis.
It tends to redistribute the load by progressively removing high contact spots.
The calculation lends itself to computer programs that are dedicated to the task. The material property data in 2101-d004 3 was taken from Jandeska et al.
2101-d4 For example, materials such as aluminum or stainless steel may encounter lubrication problems that invalidate calculations of pitting resistance and bending strength. It is caused by either static or stray electricity conducted through the gear mesh due to aga electrical grounding or inappropriate gear motor isolation. This is equivalent to a load reversal factor of 0.
B 21 23 14? In AGMA gear rating the service factor has been used to include the combined effects of required life cycles, material reliability, and overload factors in an empiri- Factor of safety also must consider human safety risk and the economic consequences of failure. The torsional and bending deflections can be calculated by normal strength of material techniques for each rotor.
The result of this equation will be that the one-way bending agmx limit will be at the agms reliability level as 2110-d04 fully reversing value used in this equation. Where specific experience and satisfactory performance has been demonstrated by successful use of established service factors, values of ZN and YN of 1. In fact, there are very few differences between the old edition, B88, and the new edition, C The agja condition factor can be taken as unity provided the appropriate surface condition is achieved.
These intersection points can then be projected back to the ordinate to determine the one-way bending endurance limit based on either the Modified Goodman or Gerber failure theories. The fully reversing bending endurance limit of a material may be found from testing gears or may be found in publications for gears.
In the rating of gears, or in predicting the failure of any mechanical component for that matter, it is vital to understand the nature of the material property data being used in the rating calculations and how that compares to the application being rated.
Generally oil film bearings provide greater damping than rolling element bearings. Experimental data from actual gear unit measurements are seldom repeatable within a plus or minus 10 percent band.
Proper evaluation of these factors is essential for realistic ratings.
The difference in nature of the stresses induced in the tooth surface areas and at the tooth root is reflected in a corresponding difference in allowable limits of contact and bending stress numbers for identical materials and load intensities.
Equation 36 therefore, can be modified to: The knowledge and judgment required to evaluate the various rating factors come from years of accumulated experience in designing, manufacturing, and operating gear units.
Figure 16 shows suggested values for allowable yield strength for through hardened steel. Consideration should be given to: When yield is the governing stress, the stress correction factor, Kf, is considered ineffective for ductile materials; hence, the stress correction factor can be taken as unity.
Therefore, the power rating for unity service factor should be based on the lowest values of the expressions for each of the mating gears. When this is done, the stress cycle factor is calculated using the number of cycles equivalent to a specific number of hours at a specific speed, to establish power rating for unity service factors. Calculated gear ratings are intended to be conservative, but the scatter in actual results may exceed 20 percent.
The knee was established based on experience of manufacturers who have successfully operated gears at rated loads with this backup ratio.