The face load factor KHβ, which in rating equations representsthe load distribution over the common face width in meshing gears,is one of the most important items for a gear strength calculation.In the international standard for cylindrical gear rating, the ISO6336-1 [1], using method C, some formulas are proposed to get avalue for this factor. But as the formulas are simplified, theresult is often not very realistic. Also AGMA 2001 (or AGMA 2101)[2] proposes a formula for KHβ, different from ISO 6336, but againnot always appropriate. Therefore a note in AGMA stipulates, that”it may be desirable to use an analytical approach to determine theload distribution factor”.
In the last edition of ISO 6336 (2006), a new annex E was added:”Analytical determination of load distribution”. This annex isentirely based on AGMA 927-A01 [3]. It is a well-documentedprocedure to get a direct and precise number for the face loadfactor.
Today an increasing number of gear designers are using toothcontact analysis (TCA) methods [4] to get precise information overthe load distribution on the full gear flank. Contact analysis isvery time consuming and does not permit to get a value for KHβ, asdefined by the ISO or AGMA standard. A contact analysis resultcombines different factors of ISO 6336 as KHβ, KHα, Zε, Zβ, ZB, ZDand buttressing effects, etc., thus to ‘extract’ KHβ from a TCA isnot possible.
The use of the algorithm, as proposed by AGMA 927, is a goodsolution to get proper values for KHβ; it is simpler and thereforemuch quicker than a contact analysis calculation. The paperexplains how this algorithm can be applied for classic gear pairrating procedure, for ratings with complex duty cycles and even forplanetary systems with interdependent meshings between sun, allplanets and ring.
- Edition:
- 13
- Published:
- 09/01/2013
- Number of Pages:
- 19
- File Size:
- 1 file , 1000 KB
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