Life Rating for Gears
Life Rating for Gears
(OP)
Can anyone advise on how gear sizes are determined for aerospace application?
When I reverse engineer a gear used in a helicopter and then use catalog calculations, the safety factor comes in a 1 or less. The safety factor must obviously be greater than 1, therefore I assume that there is an adjustment made, which is related to the life of the gear.
My questions are;
~ How is the life factor entered in to the calculations?
~ Is the life factor based on Durability or Strength?
Thanks
Dave J.
When I reverse engineer a gear used in a helicopter and then use catalog calculations, the safety factor comes in a 1 or less. The safety factor must obviously be greater than 1, therefore I assume that there is an adjustment made, which is related to the life of the gear.
My questions are;
~ How is the life factor entered in to the calculations?
~ Is the life factor based on Durability or Strength?
Thanks
Dave J.





RE: Life Rating for Gears
RE: Life Rating for Gears
What you may be missing is the principles of modified gears, like extended addendum on pinions, full fillet radius, thicker pinion tooth/thinner gear tooth, etc. When you iterate your design based on various mods, you will be surprised at the reductions in stress. I have found 1.2 extended addendum and 54% pinion tooth thickness to be very beneficial.
RE: Life Rating for Gears
Dave J.