| In recent years, with the actual need of development of production, circular-arc gear transmission has been widely applied in engineering practice. Compared with the traditional involute gear, double circular-arc gear has higher contact strength and bending strength because of its unique characteristics of tooth profile. However, normal-plane double circular-arc gear has been widely used in the project at present. In theory, this kind of gears has two defects that error sensitivity of the contact position is too big and bending strength is insufficient. In this background, research of quasi-transverse double circular-arc is very necessary.This paper firstly analyzed and deduced transverse tooth profile equation of quasi-transverse double circular-arc gear. Parametric model of quasi-transverse double circular-arc was established through the three-dimensional modeling software-Pro/E. And according to the needs, the necessary simplification and parametric assembly were done by the model. We were just needed to change the values of parameter to get normal-plane、transverse and quasi-transverse double circular-arc gear, which realized automatic generation of parts model by parameter control as well as parametric assembly of meshing components.Tooth of double circular-arc gear is a spatial helix, whose structure is very complex. So, with the aid of computer simulation technology, it has the very vital significance to study the effect of parameters on it. Especially, quasi-transverse double circular-arc gear introduces a new parameter-the setting spiral angle β0. It has a guiding significance for the engineering application of quasi-transverse double circular-arc gear to study the effect of the gear spiral angle β and the setting spiral angle β0on the fatigue life of gear. Three-dimensional model of gear was assembled in Pro/E and then imported into the finite element analysis software-ANSYS. By adding the constraints and loads etc, this paper did the analysis and comparison of contact stress of normal-plane double circular-arc gear and transverse double circular-arc gear as well as quasi-transverse double circular-arc gear. And the analysis of contact stress for quasi-transverse double-circular-arc gear was finished when different gear helix anglep is selected with different setting helix angle β0.The analysis showed that quasi-transverse double-circular-arc gear had a greater advantage in processing technology and contact strength.As the main mechanical components, the fatigue damage of gear often instantaneously happens, which seriously affects the production efficiency and causes immeasurable economic losses, even brings about unimaginable consequence. Therefore, based on the five tooth model of gear as the research object, the analysis and contrast of root bending stress for normal-plane double circular-arc gear and transverse double circular-arc gear was finished when the gear helix angle β was different, and the analysis of root bending stress for quasi-transverse double circular-arc gear was emphatically conducted when different gear helix angle β was selected with different setting helix angle β0.On this basis, this paper researched and analyzed the change rule of fatigue life for normal-plane double circular-arc gear and transverse double circular-arc gear with the gear helix angle β as well as the change trend of fatigue life for quasi-transverse double circular-arc gear with the gear helix angle β and the setting helix angle β0, which is of great significance to timely maintain and replace the gear. |
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