For the variable hyperbolic arc gear, when the radius of the tooth line is small, the tooth profile surface of the gear is a hyperboloid with constant curvature; when the radius of the tooth line is large enough, the gear is similar to the involute cylindrical gear. In order to explore the influence of the tooth line radius on the meshing stiffness curve, the tooth line radii of 100 mm, 200 mm and 375 mm were selected respectively, and the load of 20 N · m was applied. Through finite element post-processing, the meshing stiffness curves of gear pairs corresponding to different tooth line radii in one meshing cycle can be calculated, as shown in Figure 1.

It can be seen from Figure 1 that when the tooth line radius is different, the overall change trend of single tooth meshing stiffness curve is the same. With the increase of the tooth line radius, the peak value of the stiffness curve gradually decreases, and the peak value of the stiffness curve with the tooth line radius of 100 mm is about 200 MN / M larger than that with the tooth line radius of 375 mm. It can be seen that the meshing stiffness decreases with the increase of the tooth line radius, and the tooth line radius is also an important parameter affecting the meshing stiffness of the variable hyperbolic arc tooth line gear.