No 2 (2017)

Articles

GENERALIZED TRACTION INDICATORS OF AGRICULTURAL TRACTORS

Gorodetskiy K.I., Parfenov A.P., Lavlinskiy A.M.

Abstract

In 1972 G.G. Kolobov and A.P. Parfenov published the monograph «Traction characteristics of tractors». The monograph generalized numerous results of field tests of domestic wheeled and caterpillar tractors of that time, conducted by machine testing stations in various soil and climatic zones of the USSR. This had an impact on formulation and study of the issue of determining of tractors slippage, and in general, the study of their traction characteristics. Averaging of the experimental data was carried out according to the formulas and coefficients developed by the authors of the monograph. The obtained dependencies, hereinafter referred to as traction characteristics of tractors, establish the dependence of the coefficient of usable traction (specific traction force on the hook) on the slipping of tractors of various types on different soils. By now, the concept of the role of the studies in research of the interaction of a wheel and track with the surface has changed. The standards have been introduced to limit slipping of agricultural tractors, considering the negative impact of their propulsors on the soil. There is a need to clarify the terminology used earlier in order to unify the same meaning terms used in different, but related technical disciplines. Objectives of work are: rethinking of previous research results and assessing their relevance; distinction between the physical meaning and concepts of the traction coefficient and the coefficient of usable traction (specific traction force on the hook); determination of traction capabilities of wheeled and caterpillar tractors on natural agrotechnical and asphalt-concrete surfaces, considering current slippage limitations. It was proposed for the purposes of engineering calculations in assessing traction performance of tractors to use as a traction coefficient of various propulsors its value corresponding to the maximum slipping on the appropriate agro-technical background or dry concrete. It is also found that the limitations on slipping of tractors on metal caterpillars are overstated on all soil backgrounds, since they rather characterize the «stop» mode of the tractor, than the beginning of the unstable operation of the engine. The parameters of traction characteristics of 4x4 wheeled tractors require correction based on statistical replenishment with the initial data on traction tests of such tractors having a layout that considers the increased role of the front drive axle in creating the tractor pulling power. For 4x2 tractors traction characteristics are at the same time characteristics of traction performance of individual driving wheels (tires). Therefore, having such data on all available driving tires of different dimensions, it is possible, at the development stage, to determine traction properties of newly created different variants of machines, including all-wheel drive.
Tractors and Agricultural Machinery. 2017;(2):3-8
pages 3-8 views

INSTALLATION FOR THREE-DIMENSIONAL DYNAMIC MEASUREMENT OF THE TILLING TOOLS AND THE RESULTS OF ITS USE

Dontsov I.E., Lysych M.N.

Abstract

For effective work of forestry and agricultural tilling equipment it is important to have information about the power parameters of tilling tool. The purpose of the research is to develop a device that can give an idea about changing the power parameters of tillage tool in all three planes of projections for the unsteady motion of the tractor with a tillage tool. This method is based on the model of force interaction of tillage implements with the soil, suggested by Professor L.V. Gyachev. The article is devoted to the study of power parameters of passive, active, and rotational tilling tool. A setup was designed to measure power parameters of tillage tool in three planes of projections. The installation to determine the power parameters of the tillage tool includes the following basic elements: soil channel, traction trolley, attachments and devices for converting of electrical signal and recording of the measured values. The sensors include: force sensors in linkage bars and sensors of working body movement. Electrical signals from sensors are served on an analog input module. Then the signals are supplied to the inverter interface. Next, the signals are processed on a computer. In the experiment, the tillage tool is set in various positions relative to the main (straight) movement, recorded are the parameters characterizing the coordinates (function arguments) and forces in the linkage (functions). Then the characteristics of the main force vector and main torque of the forces resultant of tillage tool interaction with soil are calculated. The results of several measurements are approximated by the curve most appropriate to the nature of the interaction. The obtained data are used in the study of stability, oscillations and dynamics of non-steady motion of tillers and tractor units.
Tractors and Agricultural Machinery. 2017;(2):9-15
pages 9-15 views

JUSTIFICATION OF TECHNOLOGICAL AND DESIGN PARAMETERS OF THE COLTER FOR WINTER WHEAT SEEDING IN COTTON ROW-SPACING

Igamberdiev A.K.

Abstract

In Uzbekistan, over 800 thousand hectares of irrigated area are used to grow winter wheat in row-spacing of growing cotton. They are mainly sown by spreading, then seeded with cotton cultivators. Disadvantages of the spreading method are high seed rates by 30...40 % and excessive energy costs due to multiple (3...4 times) passes of the unit. However, the issues related to the establishment of the dependence of the quality of cereal crops in cotton row-spacing on the main parameters of the colter and the row profiles in Uzbekistan have not been adequately studied. In this regard, the materials of a theoretical study on the justification of technological and constructive parameters of the colter for sowing winter wheat seeds in the row-spacing of cotton are presented. As a result of the carried out research, it has been established that for the quality sowing and shaping of the seed beds the colter must be submerged in the soil to a depth of 2.0...4.0 cm. In order to form a slightly compacted furrow shape, the colter must be pressed to row-spacing surface. To ensure the non-heap of soil piles through the wings of the colter, their height should be 14...18 cm. In this case, the angle of installation of the wings in the continuous direction of colter movement should be equal to a = 47°, and the angle of the colter wing spread у = 69°. The given constructive parameters of the colter are optimal for sowing winter wheat seeds in the cotton row-spacing. The proposed new technology and colter design implements multi-row seeding from 5 (for 60 cm spacing to 9 rows (for rows between rows 90 cm). Due to formation of a new loose shape of the row spacing, the useful seed sowing area is increased by 9...22 % compared to the spreading method and conditions are provided for uniform seeding and obtain good and even sprouts.
Tractors and Agricultural Machinery. 2017;(2):16-20
pages 16-20 views

INVESTIGATION OF STRENGTH PROPERTIES OF IMPELLERS MADE OF COMPOSITE MATERIAL FOR DIESEL ENGINES

Netrusov A.N., Fomin V.M.

Abstract

The purpose of the paper is to perform a comparative analysis of the strength properties of impellers made of a composite material with strength properties of impellers made of aluminum alloy. The main method of this study is the finite element method. Pre-and post-processor Femap was used to prepare the model and process the research results. The calculations were performed using a linear solver NX Nastran. Calculations are carried out for two wheel sizes (two diameters) and two calculated cases (for maximum working angular velocity and for destructive velocity). During research stress-deformed states of impellers were obtained. Stress distribution is qualitatively identical in all design options. Redistribution of stresses in impellers due to different materials stiffness is absent. Strength factor as a result of replacement of materials for the 1st and 2nd sizes fell by 7.8 and 5 %, respectively (absolute values - 1.06 and 1.16 respectively). Stress-deformed states obtained during strength calculation can be used for the subsequent manufacture of an impeller made of an anisotropic material. The calculation of frequencies and forms of free oscillations showed a decrease in the frequencies of free vibrations of impellers made of composite material, but it should be noted that even the «lowest» frequencies have approximately twice the maximum frequencies of the working range of the turbocharger. The results of the analysis show the promise of replacing materials in order to improve reliability. Strength calculation showed the need for additional experimental studies of impellers made of composite materials.
Tractors and Agricultural Machinery. 2017;(2):21-28
pages 21-28 views

METHOD OF DETERMINING WEAR OF FAN BLADES CRUSHER GRAIN

Goeva V.V.

Abstract

It is scientifically proven that the main factors affecting the productive potential of the animals, are the structure of fodder farms, the quality of feed and methods of feeding. It is known that concentrated fodder are an important component in the diet of animals and contribute to a stronger manifestation of their productive potential. For grinding grain into livestock is usually used crusher with different working bodies. The most widely is spread hammer mill grain crusher. This happens due to the simplicity of their construction and relatively high resource of working bodies. Currently, for farmers are of great interest the small-sized feed factories and units, which include crusher grain with a fan. However, along with the obvious advantages of hammer crusher, like with forced feeding of material and with pneumatic, have a number of disadvantages, one of which is the increased wear of their working bodies: hammers, screens, fan blades. The greatest interest from the point of reducing wear represent fan blades, as changing their shape, it is possible to reduce or increase the intensity of wear. In addition, they are more prone to wear, since all of the crushed material passes through them with great speed, while in the grinding chamber, the amount of grain distributed over a larger number of hammers, and the relative velocity of grains in it decreases. The analysis showed that the intensity of wear of working surfaces of the blades of the fan depends on the coefficient of friction of grains on the blade, the angle of the blade to the radius of the rotor disc, and the greatest influence on friction force has a peripheral speed of the blades. To increase the service life of the blades and reduce the intensity of wear and tear it should be choosen the correct form of the smallest possible radius of curvature. The method is proposed on the basis of which it is possible to calculate the amount of wear of fan blades, taking into account its aerodynamic characteristics.
Tractors and Agricultural Machinery. 2017;(2):29-34
pages 29-34 views

POWER ANALYSIS OF DUAL-FLOW HYDROMECHANICAL GEARS

Sharipov V.M., Shchetinin Y.S., Gaev S.V., Troshkin O.V.

Abstract

Dual-flow hydromechanical transmissions are becoming increasingly widespread in the designs of modern land transport and traction machines (tractors, automobiles and high-speed crawler vehicles). This happens mainly due to the desire to increase the efficiency of transmission, although the capabilities of dual-flow hydromechanical transmissions are broader. In order to select a dual-flow hydromechanical transmission scheme in relation to specific operating conditions, it is necessary to know the advantages and disadvantages of various schemes, their potential capabilities. The evaluation of the operation of each circuit can be made on the basis of their kinematic and force analysis. The article deals with 12 dual-flow schemes of hydromechanical transmission with a differential element in inlet and outlet with a mixed meshing of gears, the results of the power analysis are shown. For the estimated parameters of a double-flow hydromechanical transmission were taken: й - power ratio of a double- гмп flow hydromechanical transmission; ан - coefficient of loading of the pump wheel of the torque converter; ам -load factor of the mechanical branch of the closed transmission contour; аa - load factor of the solar gear of the three-link differential mechanism. For each of the schemes considered, analytical dependencies of the estimated parameters on the internal parameters of the hydromechanical transmission were obtained. For the parameters were used the characteristic k of planetary gear set, power йгт and kinematic игт gear ratios of torque converter. It is assumed that, at the boundaries of the range й = да and й = 0. Calculations have been performed to determine the parameters й , гмп гмп гмп ан , ам u аа for different values of k and й , results of which made possible to evaluate the potential transforming properties of the schemes of two-flow hydromechanical transmissions independently of the model of the used hydrotransformer.
Tractors and Agricultural Machinery. 2017;(2):35-41
pages 35-41 views

DETERMINATION OF DIFFERENT METHODS OF TRACTORS DIESEL ENGINE PRE-START PREPARATION AT ITS STARTING CHARACTERISTICS

Bondar V.N.

Abstract

The article presents the results of an experimental study of a tractor diesel engine 4CHN15/20,5, equipped with various pre-start preparations tools, starting characteristics in a climate chamber at low ambient temperatures. The purpose of the study is the determination of different methods of tractors diesel engine pre-start preparation at its starting characteristics. Engine was sequentially equipped with electric starter system, together with the liquid starting preheater, and starter engine, which exhaust gases were used for oil heating in the crankcase of a diesel engine. On the engine was installed hydrotransformer that allowed to reproduce the actual conditions of engine operation more accurately. The study found out that engine with liquid starting preheater always starts at ambient temperature not lower than minus 30 ° C, but the pre-start preparation time is longer than one hour. Long warm-up time leads to discharge of even fully charged and warm batteries, which limits the start of diesel engine at lower temperatures. The use of a heater only for heating the coolant with heated oil in the diesel fuel tray with the exhaust gases of the heater slightly increases the rate of heating of the oil, compared with the use of water-oil heat exchangers, and has practically no effect on the speed of heating the coolant. Using the starter engine with forced coolant circulation and exhaust gases outlet for heating the crankcase and oil pump, allows to start diesel with cold batteries at minus 40 ° C during 30 minutes, that corresponds to the requirements of existing regulations. Results of the study were used for the modernization of production and development of new "Uraltrac" tractor diesel engines models and can be recommended for implementation in diesel engine companies.
Tractors and Agricultural Machinery. 2017;(2):42-46
pages 42-46 views

PERSPECTIVE STRUCTURES OF MACHINE AND TRACTOR UNITS FOR OPERATIONS COMBINATION

Maslov G.G., Zhury I.A.

Abstract

Perspective structures of machine and tractor units for combination of technological operations when performing of the field mechanized works are offered. Combination is based on the operations coinciding on agrotechnical terms of the performed works: introduction of mineral fertilizers - stubble processing of the soil; hulling of an eddish - application of fertilizers; chisel plowing soils - introduction of mineral fer-tilizers; crops of intermediate cultures - processing of the soil and etc. Efficiency of combination is determined by higher quality of the performed works without gap by time, moisture economy, elimination of the losses brought in the soil of materials (seeds, fertilizers, pesticides), respect for threading and rhythm of production processes, decrease in need for the equipment and a labor power and all cost types (labor, cash, energy). All this promotes increase in competitiveness of the made products. Completion of the offered new structures of multipurpose aggregates is based on use of the serial basic machines checked in production (deep-rippers, plows, cultivators, disk tools, seeders, etc.) equipped with various devices for introduction of mineral fertilizers, seeds, their seal which are also checked in or-dinary operation to the soil on the optimum depth and a compacting of crops. Except economic effect of combination of transactions by the provided aggregates are obvious agro-nomical and cost efficiency: decrease in consolidation and a puddled condition of the soil that influences its fertility, complete use of soil moisture that guarantees amicable shoots and future harvest.
Tractors and Agricultural Machinery. 2017;(2):47-52
pages 47-52 views

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