In the transmission process of helical gears, their tooth surfaces are in contact with each other, and the tooth surface contact pressure generated by the teeth at different meshing positions is different, which is an inevitable characteristic of involute helical gears in the transmission process. With the rotation and deformation of helical gear, the size of contact area and contact stress change, which is also unpredictable in advance. Therefore, the meshing of helical gears is a highly nonlinear behavior with boundary conditions, which requires a lot of computational resources. Therefore, it is very important to carry out effective calculation to understand the characteristics of the problem. In this chapter, the finite element contact analysis of helical gear is carried out by using the finite element software ANSYS / LS-DYNA and ANSYS from different driven and static angles, and the magnitude and distribution law of contact stress of helical gear in the meshing process are compared and analyzed; Determine whether the contact strength of involute helical gear meets the design requirements.
The contact force of the helical gear pair is accurately divided into the contact force and the contact stress in the ANSYS / hyls software.
In the static contact analysis, the equivalent stress nephogram of the driving and driven gears is obtained by solving, and the position of the meshing line in the contact area, the equivalent stress at different meshing positions and the position of the maximum contact stress are determined and analyzed; In the dynamic contact analysis, the equivalent stress nephogram of the driving and driven gears at different times in the whole meshing process and the equivalent stress curve of different meshing positions at different times are obtained by solving. By comparing the calculation results of the dynamic and static contact analysis of helical gear, the following conclusions are drawn: regardless of the dynamic and static contact analysis, the contact line is an inclined line with a certain angle with the edge of the tooth, and the position of the maximum stress is the position of the tip angle of the helical gear tooth which is easy to cause stress concentration; The stress obtained from the dynamic contact calculation of helical gear is greater than that obtained from the static contact calculation of helical gear. This is because the load deformation of helical gear pair will produce relatively large meshing in and meshing out impact, resulting in strong vibration and impact.
