The results of the study of the rigidity of tires of tractor wheels and its effect on tractor vibrations

Abstract

The work is devoted to a theoretical study of the rigidity of pneumatic tires of tractor wheels and analysis of its influence on the vertical oscillations of tractors. Mathematical modeling of the patterns of deformation of elastic tractor wheels and soil using experimental data was performed. These experimental data on the patterns of deformation of the studied soils were obtained in our works earlier in field trials, when normal stresses at the contact of the wheels and the soil, as well as the density and humidity of the soil loosened before the wheel passes and after successive wheel passes along the same track were meas-ured. According to the developed computer program, which allows to calculate the rigidity of tires of tractor wheels, one-factor and full factorial computer experiments of three types were carried out. In computer experiments of the first type, the dependence of tire stiffness of a number of elastic wheels under the MTZ-82 tractor on the soil operation from air pressure at different vertical dynamic loads on the axes of the respective tractor wheels was investigated. According to the results of computer experiments of the first type, the regression equations, reflecting the dependencies studied, were found. In computer experiments of the second type, the tire stiffness of various sizes on tire pressure with constant vertical dynamic loads on the axles of the wheels was investigated. According to the results of computer experiments of the second type, the regression equations were found, reflecting the corresponding dependencies. High values of correlation relations for the obtained regression equations indicate a great closeness of relations in the correlation dependences found. In computer experiments of both types, the deviations of the wheel-soil interaction values, found using tire stiffness values obtained by calculation, are within the limits of measurement accuracy of experimental data. Computer experiments of the third type are performed using the experimental data obtained in authors works. The vertical oscillations of the axles of the MTZ-82 tractor for different values of the rigidity of the tires of the front and rear wheels were calculated. The graphs that characterize these fluctuations were built. The results of the study show that with an increase in tire stiffness, the amplitudes of the vertical axes of the tractor axles decrease. This helps to improve the smoothness of the tractor and reduce its sealing effect on the soil. By calculation, it was found out that wheels with 18.4R38 tires are optimal on the rear axle of the MTZ-82 tractor.