RESEARCH OF OSCILLATIONS OF A TRACTOR DRIVING CLASS 3kN AND WAYS TO IMPROVE ITS RIDE SMOOTHNESS WITH REDUCING SPRING TENSION

Abstract

In order to improve the smoothness of the course of the T-150K tractors, the possibilities of changing the main parameters of the suspension system and its influence on the intensity of low-frequency oscillations of the machine were considered. The stiffness and drag coefficient of the front suspension, as well as the base of the machine, were subjected to changes, and the range of variation was limited by the possibility of implementing the parameters without rearranging the units and changing the traction characteristics of the machine. As criteria for evaluating the smoothness of the ride, the values of the transfer function of the movements of various points of the frame, seat and root-mean-square accelerations during the movement of the tractor along natural irregularities were taken.
 Based on the results of these studies, it was found that an increase in the tractor base by 10% has an insignificant and contradictory effect on the root-mean-square accelerations of the frame point over the rear axle over the entire range of design speeds from 2.5 to 7 m/s, and acceleration over the front axle and on the seat - up to a speed of 5 m/s. With a further increase in speed to 7 m/s (25 km/h), an increase in the tractor base by 10% reduces frame acceleration over the front axle by 15%, and on the seat by 20%. In addition, 11-leaf springs (when removing the 5th and 7th sheets), installed in the suspension with tractor hydraulic shock absorbers with optimal parameters, created on the basis of automobile shock absorbers of the MAZ-500E type, have smaller dynamic deflections during compression, than 13-leaf springs (suspension without hydraulic shock absorbers). According to this, the dynamic load on the 11-leaf spring, compared to the serial suspension, is reduced by 51% when the KhTZ-150K tractor is moving along a dirt road and by 30% when plowing the field across the furrows. Consequently, the stress on the sheets of an 11-leaf spring in the presence of shock absorbers in the tractor suspension will be less than that of a 13-leaf spring (without shock absorbers), which will ensure increased durability of the 11-leaf spring. In addition, the resource of the last spring should be increased by reducing the number of load cycles, since the suspension with these springs reduces the frequency of the tractor by 10% (according to experimental data).