## 3 Results
Values of \(\psi_{bd}\) selected according to the recommendations in Figure 4:5 By choosing \(\psi_{bd}\), determine \(\psi_{ba}\) by formula \(\psi_{ba}=\frac{2\psi_{bd}}{(u+1)}\). Figure 4:6  
Formulas (5), (6) and (8) follow the trend that the value of contact stresses \(\sigma_{H}\) does not depend separately on the modulus or on the number of teeth but is determined only by their product or wheel diameters. According to the conditions of contact strength for given \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Position of Wheels**} & \multicolumn{2}{c}{**Hardness of Active Tooth Surfaces**} \\  & **Title 3** \\ \cline{2-3}  & **HB\({}_{1}\leq\) 350 or HB\({}_{1}\) and HB\({}_{2}\leq\) 350** & **HB\({}_{1}\) and HB\({}_{2}\) \textgreater{} 350** \\ \hline \hline \multicolumn{1}{c}{Symmetrical} & 0.8\(\ldots\)1.4 & 0.4\(\ldots\)0.9 \\ \hline \hline \multicolumn{1}{c}{Unsymmetrical} & 0.6\(\ldots\)1.2 & 0.3\(\ldots\)0.6 \\ \hline \hline \multicolumn{1}{c}{Cantilever} & 0.3\(\ldots\)0.4 & 0.2\(\ldots\)0.25 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Values of recommended coefficients according to diagnostic parameters. \(d_{1}\) or \(a\), the transmission modulus can be as small as desired or correspond to the equality \(mz=d_{1}\) and \(m\) (\(z_{1}+z_{2})=2a\). The value of \(m\) is selected based on practical recommendations and diagnostic parameters, and then the tooth is tested for bending fatigue. When checked, it is possible to obtain \(\sigma_{F}\) much smaller than [\(\sigma_{F}\)] because the load capacity at tooth surface hardness \(H<350\) HB is limited by contact fatigue rather than bending fatigue. If the calculated value exceeds the permissible value \(\sigma_{F}\), then at the accepted values of \(d\) and \(m\) increase \(m\). This means that bending fatigue, rather than contact fatigue, is decisive in a given transmission of the selected materials. In practice, such cases occur in the case of wheels with high-hardness teeth at the \(H>50\) HRC. The following should be considered when selecting a module. Fine-modular wheels with a large number of teeth are better for smooth running conditions (\(\epsilon_{a}\) increases) and for economic reasons. However, for power transmissions, it is recommended to take \(m\geq 2\) MM. In high-speed gears, it is recommended to use the following for noise reduction \(z_{1}\geq 26\). Large-modular wheels can operate for a long time after the onset of pitting and are less sensitive to overloading. Given these diagnostic parameters, the following recommendations should be used in the orientated evaluation of the module. 1. By choosing \(\psi_{m}\) from Table 2, determine \(m=\frac{b}{\psi_{m}}\), where \(b=\psi_{bd}d_{1}\); \(d_{1}\) is obtained from the contact fatigue calculation. If \(a\) is obtained from the calculation, then we determine \(d_{1}=\frac{2\,a}{(u\pm 1)}\), then \(\psi_{bd}=\frac{\psi_{bd}(u\pm 1)}{2}\), \(b=\psi_{bd}d_{1}\) and further \(m\). 2. The modulus is chosen according to empirical dependencies:  
\(m=(0.01\ldots 0.02)\)\(a_{V}\)--at hardness of gear and wheel teeth \(H\leq 350\) HB;  
\(m=(0.01\ldots 0.02)\)\(a_{V}\)--at hardness of gear and wheel teeth \(H\geq 45\) HRC. The obtained modulus value is rounded to the values of GOST 9563. Row 1: 1, 1.25; 1.5; 2; 2.5; 3; 4; 5; 6; 8; 10; 12; 16; 20...  
Row 2: 1.125; 1.375; 1.75; 2.25; 2.75; 3.5; 4.5; 5.5; 7; 9; 11; 14; 18; 22.2... When assigning modules to Row 1, you should give preference to Row 2. When selecting \(\psi_{ba}\), it is recommended to use a number of:  
0.1; 0.125; 0.16; 0.2; 0.25; 0.315; 0.4; 0.5; 0.63; 0.8; 1; 1.25. II. Next, we calculate the bending fatigue resistance of the wheel teeth. This calculation is the basic calculation for gears with high hardness of the tooth surface (at \(H\geq 350\) HB). The purpose of the calculation is to establish the dependence of the operability index (stress \(\sigma_{F}\) in the tooth foot section) on external loading and geometric dimensions of the teeth.