As the power density of gear sets increases, mesh deflectionsincrease, and the variations in those deflections, which resultprimarily from mesh stiffness variation, become increasinglysignificant. This is because these variations translate directlyinto transmission error and provide the excitation that generatesthe periodic inertial load supplement called “the dynamic incrementof load”. In addition to subtracting from the useful torquecapacity, the dynamic increment is the main generator of gearnoise. To minimize these undesirable effects, designers of powertrain gear pairs have traditionally specified various forms ofprofile modification, the most common of which is tip and/or rootrelief. The problem with these conventional modifications is thatthey give only a limited reduction in transmission error at aparticular roll angle and load (the “design load”) but produceincreases in transmission error at other roll angles and loads. Anew system of modifications, however, has recently been devisedthat substantially eliminates mesh stiffness variations throughoutthe entire engagement angle regardless of what torque load is beingtransmitted. This new system of modifications is described andconfirmatory test results are reported. By substantiallyeliminating gear noise and dynamic increment, the new modificationsmake it possible to replace costly helical gear sets with betterperforming spur sets in many applications. In addition, gear setsembodying these new modifications are significantly less sensitiveto profile manufacturing errors than gear sets having tip and/orroot relief. Together, these features can lead to substantialreductions in cost without compromising performance.
- Edition:
- 96
- Published:
- 10/01/1996
- Number of Pages:
- 6
- File Size:
- 1 file , 460 KB
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