Zihni B. Saribay

Tooth geometry and bending stress analysis of conjugate meshing face-gear pairs

The conjugate meshing face-gear pairs are implemented to high shaft angle intersecting axis gears such as the pericyclic transmission system. The meshing face-gear pair tooth surfaces are generated with a mutually conjugate spur shaper. The established tooth geometry and the dimensions of the conjugate face-gear pairs are summarized in this article. Four different example face-gear pairs are generated at various shaft angles and numbers of tooth combinations. Tooth bending stresses of these face-gear pair teeth are investigated based on finite element analysis methods. In these analyses, only single pairs of teeth are investigated. These results are compared to analog the spur gear tooth bending stresses calculated by finite element analysis and standard spur gear stress formulas. Meshing face-gear pair single tooth bending stress levels show approximately 3% to 6% difference from same size spur gear tooth.

Analysis of Pericyclic Mechanical Transmission with Straight Bevel Gears

A design methodology for a Pericyclic mechanical transmission utilizing straight bevel gears has been presented. By virtue of its very high reduction ratio in a single meshing stage, the pericyclic transmission holds promise for significant transmission weight reduction compared to state-of-the-art concepts. Assembly, gear geometry and kinematics of the drivetrain leading to a high reduction ratio while having a very high contact ratio (~8-10 teeth in contact) has been discussed. Tooth contact behavior has been studied in detail. A load distribution model has been developed that can be easily generalized to any internal-external bevel gear mesh. A rolling/ sliding velocity analysis has also been carried out, taking nutational motion into account. This is further used to determine the elastohydrodynamic lubrication characteristics of the meshing gear pairs. The methodology was applied to a conceptual design, resulting in acceptable levels of predicted contact stress and transmission efficiency.