Vol 86, No 3 (2019)

The introduction of advanced technologies for the cultivation of crops is usually associated with min-imizing the techniques of basic tillage and replacing them with surface operations, including disking. The use of low-power wide-grip tools, working at a depth of 10...14 cm with high speeds of up to 15...20 km/h, allows you to provide an economic effect, reduce the time for spring work, and reduce the number of service personnel. Sometimes the same effect can be achieved through the use of combined machines that perform several successive operations for tillage, fertilization and sometimes sowing in one pass. In recent years, disc rippers with individual spring-loaded mounting of discs to the frame (diskators) and milling cultivators that fit organically into the combined machines are used for such purposes. However, now long-term observations of the use of these expensive and complex tools, along with high tool traffic, increased working speed and reliability of the process, fuel economy, etc., revealed a number of significant shortcomings in relation to cultivated crops - gradual soil compaction, especially chernozem, decrease in productive moisture, increased contamination of fields, uneven depth of processing, increase in erosion-hazardous particles and, as a result of all this, a tendency to decrease in yield. In addition to high quality crumbling of the soil, drive machines have, especially domestic mills, low productivity, low reliability, high fuel consumption and an increase after passing through erosion-hazardous fractions. This is facilitated by the lack of multi-speed gearboxes on our cutters, which usually make it possible to regulate the quality of crumbling by controlling the kinematic parameter - the ratio of peripheral and translational speeds. The purpose of the study is to identify cases of irrational use of so-called. «Aggressive» tillage tools and identify ways of minimizing possible deficiencies noted. The research methods consist in analyzing the deficiencies arising from the operation of the selected type of tools, identifying the causes of their occurrence and indicating concrete steps to eliminate them. The results of the research are presented on real models currently being produced in Belagromash-Service LLC, for which the load characteristics of the most popular samples are given. In order to avoid the irrational use of the considered modern tools, a number of measures are given to increase the efficiency of their use, the yield of cultivated plants and the efficiency of tools by reducing the negative impact of working bodies on the cultivated soil (for diskators) and the drive for milling machines.

The paper deals with the design of a front loader using three-dimensional modeling, and its manufacturing. The area of use of the front loader is individual farms with a small but regular need for the volume of transported goods. The existing loaders have greater productivity and correspondingly high cost, which is not suitable for individual farms. The task is to design a simple and reliable front loader that can be aggregated with an MTZ tractor. The loader must have a maximum load capacity of 1000 kg with a safety factor of 2...2,5. The front loader was designed and manufactured. The design was carried out in a three-dimensional CAD software SolidWorks, the calculation of the maximum load was made by the finite element method. During calculations, the optimal geometrical parameters of the loader parts, capable of withstanding a given load with minimum stresses, were determined. The kinematics of assemblies and parts were made and tested allowing the structure to perform its functionality correctly along a given trajectory. The front loader was made on the basis of an individual farm. The available materials for the production of this loader were: channel, pipe, angle bars, 40 mm thick solid metal and standard units - hydraulic cylinders and high pressure hoses. Tests for loading logs have shown that the device is reliable and has good performance. No complaints and comments on the work of the loader were noted. The measures to improve the loader are outlined. These are the development of a rotary assembly of a vertical stand, reinforcement of the boom anchoring axis, development of tractor stoppers. This will allow mobile work with a load of more than 1000 kg.

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.

The article presents an approach to the schematization of the processes of random stationary and non-stationary loading of the vehicle structural frame from the side of the wheels and traction coupling devices, as well as deterministic loading from the operating functional systems. In order to reduce the amount of input data for calculating durability, it was proposed, first, to identify loads that are linear combinations of each other, and second, to replace the correlation table of average and amplitude values obtained by processing the original implementation with linear combinations of correlation tables of shorter sections. The expression of some components of the load through other components by multiplying by some predetermined constant allows to reduce the number of independent arguments and, therefore, the duration of the calculation. Similarly, the optimization of the correlation table of the entire record consists in finding the intervals of the same record with such correlation tables that, after applying simple transformations (summation and multiplication), are able to reproduce the original correlation table with a given error. Then the calculation of durability can be performed only for the intervals found, and with the results of the calculation to do the same operations as with the correlation tables. The calculation time can be reduced, the results of the calculation of fatigue life from the schematized realizations will be equivalent to the results of the calculation of the fatigue life from the original realizations by virtue of the theory of linear summation of damage. The approach was tested when schematizing the loading of a combine harvester (ZUK) of the sixth class, developed at Rostselmash, the errors in calculating the durability of the schematized loads were estimated. The reduction of the computation time from schematized implementations in comparison with the initial implementations is shown.

The development of new materials and coatings with increased wear resistance, used in friction pairs, is an urgent task. Its solution is aimed at ensuring reliability and dependability of work during operation. One of the new and promising functional materials for the manufacture of dense and durable parts and products subjected to intensive wear during operation is the powder material of the TiC-SiC system, ob-tained by an energy-saving and more productive than hot pressing method - spark plasma sintering (SPS). The aim of the work was to obtain and study experimental samples of friction pairs made of a composite material of the TiC-SiC system by the method of mechanical activation and SPS. The goal is aimed at solving problems of increasing the service life of the mechanical seal of the centrifugal pump 16-08-140SP diesel engine cooling system D-160 (180) for the tractor T10. The processes of consolidation of powder mixtures, including containing aluminum oxide. It has been established that the introduction of aluminum oxide prevents compaction during sintering and increases the porosity of the material. The optimum sintering temperature corresponds to 1350 °C. The resulting material has high hardness and wear resistance. Parts of a friction pair for a pump mechanical seal were manufactured and tested. Bench tests of parts showed that the wear rate with dry friction is 4,49 ∙ 10-9 mm of wear / mm of the friction path. When working in the coolant, there is an additional burnin, which reduces wear, friction coefficient and increases the tightness of the mechanical seal. The developed material has an earnability, so the surface is smoothed during operation, which is not typical of other ceramics of this purpose.

The issue of ensuring the reliability of internal combustion engines is an urgent complex task, solved in different directions. Important among which are the operating conditions, the type of fuel used, monitoring the condition of engine oils, as well as the rationale for the service life of oils. When improving the design of tractors, it is necessary to take into account the issue of increasing their reliability and durability during operation. The studies show that 40-45 % of failures of agricultural machinery are caused by engine breakage. It is rational to solve the problem of improving the reliability of the engine, determining the state of the aggregates and machine parts on the content of wear products in the oil during engine operation, and making informed decisions to improve the condition of the oil. In order to improve the performance properties the additives are used. In order to determine the effect of the continuous use of additives to the oil, a cylinder was designed, comprising a housing, a cylindrical element for the additive, a cap, an inlet nozzle and an outlet nozzle. The element located inside the housing is filled with an additive. Engine oil lubrication system is supplied from the outside, i.e. in the annular gap between the housing and the element for the additive. In the housing, due to the temperature difference, the process of oil diffusion and additives take place. The purpose of the development of the laboratory setup was to study the influence of external factors on the process of continuous input of additives and the determination of their rational values. Studies have shown that the base number with continuous input of additives increased 1,5 times higher compared to samples of oils, used without a device for continuous input of additives. A device for introducing the additive with a filter element was tested. The operating mode of the installation was set according to the results of studies T = 85 °C, ν = 2 m/s and the concentration of mechanical impurities was 0,25 %. Operational tests of the device were carried out over a period of time until the base number dropped below 2 mgKOH/g. It follows that the oil life cycle increases on average by 15-20 %.

Is given. It is shown that «Agropilot» precision agriculture system ensures driving accuracy no worse than ± 0,05 m, the «Edelweiss» modular unified technical vision system allows to control an autonomous platform. The automated control system for shifting gears and ranges can operate in one of three modes: full automatic, semi-automatic and manual. The upper-level onboard information and control system provides automatic control of the machine-tractor unit in unmanned mode throughout the shift work. The influence of the technical level of the tractor on its performance, working speed and shift factor is considered. As a result of studies of the influence of the technical level of the tractor elements on the shift performance, it has been revealed that the design of the tractor can give an increase in productivity to 37,2 %.