The impact of the accuracy class of bearings, rotational speed, load, clearances, and fits on the vibration levels of electric motor bearing units is investigated. The ways to reduce the vibrations of mechanical origin are offered. The boundary vibration levels of asynchronous motors limited by vibration levels of 40 dB at a frequency of 5 Hz and 80 dB at a frequency of 10,000 Hz are determined. The effect of increasing the rotational speed and load on the vibration levels of bearing units has been determined, and reserves for reducing vibration while ensuring the optimum bearing preload on the shaft journal have been identified. It is established that the clearance between the cap and the bearing when it is fixed in the housing (primer) does not ensure the unambiguity of the bearing unit assembly, which results in a large variation in vibration levels compared with rigid and elastic fixation. The results of this research can be applied to all types of traction electric motors.

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Wheel-type tractors carry out a range of processing operations, with the exception of early spring work, when caterpillar tractors are used to reduce the compaction effect on the soil. Therefore, to plan the costs and reserves associated with fuel consumption, it is necessary to have an estimate of the fuel economy of the tractor in basic agricultural operations. An objective assessment of fuel consumption requires a mathematical model that describes the fuel characteristics of the engine, taking into account the speed and load torque in a wide range of variation. Verification of the model is possible only with experimental data. Since the efficiency and fuel economy of a tractor depends not only on engine performance, but also on the perfection of the transmission, the running system and the rational choice of speed, it is necessary to take into account the time-varying nature of the tractor’s traction load. The complex of agricultural operations can be divided into characteristic cycles of load change over time. This principle is the basis of PowerMix test cycles, which are conducted on a concrete track to ensure repeatability of the experiment. The use of the variable load on the tractor in the PowerMix tests is positive, but in actual field tests the results may differ due to the instability of the soil properties. On the other hand, PowerMix field cycles can be taken as standard test loads in the simulation of tractor traction tests on the ground

The results of research on the creation of induction traction electric motors (EM), which made it possible to improve their technical, environmental and operational qualities, are presented. The main criterion for assessing the quality of EM were selected vibration levels. The main research methods were experimental and statistical methods. New technologies for assembling bearing units assemblies and EM as a whole were studied. New design and technological solutions have been developed. The dynamic characteristics of structural vibration damping have been improved by methods of rational distribution of masses, stiffness and distance between supports of bearings. The achieved reduction in vibration levels makes it possible to predict an increase in the resource developed by the EМ by 2-3 times.

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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).

The main issue that has to be solved in the formation of modern systems for automatic driving of tractors is the issue of obtaining information about the current state of the machine-tractor unit relative to a given trajectory. In terms of its quality, this information should reflect the rather stringent requirements of agricultural production for the accuracy of trajectory control. Thus, to create devices for automatic driving of tractors, it is necessary to know the characteristics and properties of these machines as objects from the point of view of the theory of automatic control. When examining such machines, first of all, it is necessary to establish which parameter should be considered as input. With manual control, the feedback is closed visually on the right front wheel, more precisely at the point of contact of the wheel with the ground. The main goal of this work is to obtain equations connecting the input and output coordinates, as well as the input coordinate and coordinates of the middle of the front and rear axles of the tractor. It is also necessary to establish under what initial data a simplified equation can be used, taking into account only the kinematics of the tractor movement and not taking into account the elasticity of tires and deformation of the soil. For this, the problem is solved both taking into account the elasticity of tires and deformation of the soil, and without taking into account these factors. Frequency characteristics are compared, obtained using a simplified equation and taking into account the above factors at different speeds. During the research, the equations of motion of the tractor were obtained taking into account the deformation of pneumatic tires and soil. This equation allows you to study the movement of the tractor in the presence of external lateral forces. Such forces can be centrifugal forces when moving along a curved trajectory and forces from trailed and mounted implements on a tractor. The equation is valid for small steering angles of the tractor idler wheels. A simplified equation is obtained that does not take into account the deformation of tires and soil. This equation can roughly describe the movement of a tractor on solid ground, which is little deformed, at relatively low speeds. It is advisable to use this equation only at speeds not exceeding 1.7 m/s on dense ground. Both equations characterize the tractor as an object of regulation and allow the selection and design of an automatic steering system.