Definition of parameters of loading modes of the test bench for tractor cabin’s vibration isolators

BACKGROUND: During the operation, tractor cabin’s vibration isolators are under the simultaneous load vertical, longitudinal- and lateral-angular vibrations of the cabin. These vibrations have different amplitudes, frequencies and time-domain behavior. It is possible to simulate comprehensive operational loads on vibration isolators only with bench testing.

AIMS: Within this study, the trial to define parameters of loading modes for bench testing of tractor cabin’s vibrational isolators and to define corresponding parameters of drives of the bench loading devices was made.

METHODS: This paper presents explanation and the results of calculation of loading modes parameters for testing of tractor cabin’s vibration isolator at the bench capable of producing loads from vertical, longitudinal- and lateral-angular vibrations of a tractor cabin simultaneously, as well as the results of calculation of corresponding parameters of drives of this bench. The procedure of preparation for testing was developed. This procedure includes estimation of values of operational loads amplitudes and frequencies, the range of change of necessary velocities and torques of electric drives of the bench loading devices and identification of adequate drives with required properties, determination of behavior of force and kinematic excitation reproduced by the test bench. Exemplary calculation of parameters of vertical loading at the considered bench was performed for the AKSS-400M rubber-metal vibration isolator used in cabin suspension of the K-708.4 wheeled tractor. A number of assumptions were made in the calculation. Nominal values of velocity and torque of the electric motor drive of the vertical loading device of the bench were obtained as the results. Thus, the electric motor with the reduction gear made by TRANSTECNO was selected. Characteristics of force and kinematic excitations reproduced by the bench using electric motor frequency control were built.

RESULTS: Analysis of graphs helped to define acceptable range of frequencies reproduced by the bench for operational loads in vertical direction limited by abilities of the selected electric drive.

CONCLUSIONS: The results of calculation of electric drive parameters can be used in design of the considered bench for testing of tractor cabin’s vibration isolators, particularly in the development of loading devices (cam eccentrics, pushers, return springs).