The real tooth surface of large and small wheels is obtained by scanning measurement of spiral bevel gear tooth surface with virtual conjugate datum, and the measurement accuracy is evaluated. The model is assembled accurately without considering the installation error. When the spiral bevel gear is engaged, the convex surface of the large wheel and the concave surface of the small wheel are the meshing surfaces.
As the table shows the set parameters of the machine during gear cutting, figure 1 shows the meshing spiral bevel gear model. In this paper, three transmission models of spiral bevel gear pair are established, which are pure theoretical tooth surface, only big tooth surface is real tooth surface, and both large and small wheels are real tooth surface.
In order to quantitatively describe the distribution of tooth surface error of spiral bevel gear, the difference between actual measurement points and theoretical data points in the normal direction of tooth surface is calculated. The obtained tooth surface error distribution is shown in Fig. 2. In Fig. 2 (a), the difference between the theoretical endpoints 1 ~ 8 on the theoretical tooth surface in the normal direction is shown in Fig. 2 (b).
Divide several equidistant lines on the convex surface of the large wheel, define several equidistant points on the line, and fit the points into a surface to form a coarse mesh surface as shown in Figure 3. Fig. 3 (a) shows the theoretical tooth surface of the large wheel convex surface (meshing surface), and Fig. 3 (b) shows the real tooth surface of the large wheel convex surface of spiral bevel gear.
According to the same method as the spiral bevel gear big wheel, the theoretical tooth surface and real tooth surface of the concave surface (meshing surface) of the spiral bevel gear small wheel are established, as shown in Fig. 4 (a) and 4 (b).
