Numerical-experimental determination of dynamic characteristics of the case of the drive gear of the electric locomotive

The wheel-motor unit of freight electric locomotives is characterized by the dynamic effect of a wide range of the disturbances due to irregularities in the track. This is one of the main reasons for the high damageability of the gear casings, observed recently, and it indicates the need to improve its design. The proposed design changes for the casing should be directly related to the assessment of the level of the dynamic loading during its operation. The results of the numerical and experimental determination of the natural frequencies of metal casings of traction gear used on electric locomotives of the VL85 and 2 (3) ES5K series are presented. For the numerical determination of the natural frequencies of the enclosures, a modal calculation of the solid model of the enclosure in the Ansys Workbench software environment was performed using the finite element method. A comparative analysis of the distribution of deformation fields in the sidewalls of the casing for a casing that is not fixed to the traction engine and rigidly fixed is carried out. For the experimental evaluation of the natural frequencies of the gear casings, a vibration transducer fixed on the casing was used; the method of excitation of vibrations with a single blow was used to excite vibration. As the result of the experiment, the peak values of vibration acceleration were revealed at some frequencies, which testifies to the emerging resonance phenomena for the casing, and the values of such dynamic parameters for the casing design as natural frequency, Q-factor of the oscillating system, logarithmic damping decrement, relaxation time were obtained. The values of the natural frequencies of the gear housing are obtained by solving a system of Lagrange differential equations of the second kind. The mathematical model of the considered mechanical system created for this purpose takes into account the elastic nature of the casing attachment to the traction motor. The values of the frequencies of the natural vibrations of the gear housing obtained make it possible to evaluate its dynamic loading at the frequencies close to the resonant ones.