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Vol 89, No 4 (2022)

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New machines and equipment

Substantiation of working parts parameters of the vineyard rotary earth auger for firm soils

Gorobey V.P., Moskalevich V.Y., Godzhaev Z.A.


BACKGROUND: The study is focused on improvement of basic machines and development of new machines for digging of holes for young fruit trees in firm soils.

AIMS: Expansion of technological abilities and decrease of energy resource intensity of an earth auger with the rotary working body for the sake of replacement of technically obsolete pothole diggers.

METHODS: For working bodies parameters substantiation, the vineyard rotary earth auger, which design includes a bulk, a frame, a rod and a beam, forming the hinged forebody mechanism, whereas the bulk and the frame are linked to the attachment system of the power source, is investigated.

RESULTS: The most widespread actuators of working bodies of universal hole diggers are analyzed. Principles of shock-and-vibrational digging of a drill tool make it possible to obtain significant improvement of digging performance. The design and technological layout of an earth auger and the theoretical substantiation of working bodies parameters under the vibration effect are proposed. The amplitude of the bar reciprocating motion along the splines is not less than washer teeth height in order to transform the rotation into the reciprocating motion in the vibrational operation mode of an auger. For the vibrational operation mode of an earth auger, the simulation model, considering physical and mechanical properties of soils, geometry parameters of the working body for the sake of substantiation the number of teeth of working body drive washers are proposed. It is found that for the auger diameter increases from 0.15 to 0.35 m the number of teeth of working body vibratory drive washers, ensuring demanded vibration frequency for soil layer breaking-off by auger shares, increase from 7 to 16 pieces in accordance to technical properties of the auger and physical and mechanical properties of considered firm soils. The proposed design parameters for reducing gear box fixed to the frame and auger offset from the tractor longitudinal axis corresponding to frame rotation angle β = 33°20’ is ensured by a hydraulic cylinder, the beam length L1 is 800 mm, for pivot fixing of the frame with the length L2 of 1300 mm, the offset value up to 1500 mm.

CONCLUSIONS: The obtained results of the earth auger simulation for operation at firm soils in the case of planting perennials are given. The study is targeted to the expansion of technological abilities, the substantiation of design and technological parameters of an earth auger and the decrease of energy resource intensity of hole digging.

Tractors and Agricultural Machinery. 2022;89(4):233-241
pages 233-241 views

Theory, designing, testing

On the problem of increasing accuracy of coordinates determination of a machine-tractor unit by information and navigation equipment of a parallel driving system

Galiullin R.R.


BACKGROUND: The Federal Scientific and Technical Program for the Development of Agriculture on 2017–2025 deals with the creation and implementation of competitive domestic technologies based on the scientific achievements. Therefore, the development and investigation of parallel driving systems for a machine-tractor unit with information and navigation equipment in the direction of increasing their accuracy of coordinates determination are relevant.

AIMS: Improving the accuracy of coordinates determination of the software and hardware complex for the parallel driving system based on algorithms for correcting and filtering information data of navigation equipment.

METHODS: The simulation of the machine-tractor unit (MTU) is carried out in MATLAB/Simulink and contains the models of physical modules of coordinates correction for cases of tilt, geographic coordinates transformation into plane coordinates, orientation and velocity of the machine-tractor unit and the Kalman filter.

RESULTS: Using the proposed mathematical model, a simulation of a machine-tractor unit operation with a parallel driving system is carried out. The adequacy of theoretical studies is confirmed by large-scale bench and field tests. The scientific novelty of the study lies in the proposed algorithms for correction of datas obtained from GPS/GLONASS receivers (computer program registration certificate No. 2019617131), the implementation of the 3D visualization of the machine unit on a tablet screen with the Android operating system (computer program registration certificate Nos. 2018613106 and 2020613458).

CONCLUSIONS: The practical meaning of the present study lies in usability of the proposed algorithms for corrections and filtration of navigation equipment data under creating modern hardware and software systems for parallel driving of a machine-tractor unit.

Tractors and Agricultural Machinery. 2022;89(4):243-254
pages 243-254 views

Assessment of influence of the Common Rail system high-pressure fuel pump design on regularity of fuel supply to a fuel accumulator

Kulmanakov S.P., Tyutikov S.A.


BACKGROUND: At the present time all worldwide diesel engine manufacturers have directed their development strategies on the way of reduction of harmful emissions, fuel efficiency improving and increasing of the power per liter. Using only accumulator type system is not sufficient for the goals achievement. It is necessary to use new auxiliary units, such as an exhaust catalyst, an exhaust recirculation system, injection of additional liquids together with diesel fuel, as well as to improve the existing units. Increasing the accuracy of injection rate of a nozzle will make it possible to adjust the engine fuel system more precisely, that will have a positive effect on all development directions of diesel engine engineering. Injection rate of a nozzle is dependent on fuel pressure in the nozzle inlet and on control signal timing. Pressure pulsation with stable timing cause irregularity of injection rate of a nozzle. Possibility of decreasing of nozzle inlet pressure pulsation is mainly defined by design of a high-pressure fuel pump, as it supplies fuel partially. The design optimization will make it possible to increase the accuracy of injection rate, that will make a positive effect on development of the diesel engines promising areas.

AIMS: Study of irregularity of fuel supply by fuel pumps of various diesel engines designs with the Common Rail fuel accumulation system, aimed to decrease fuel oscillations and to improve stability of injection rate of a nozzle.

METHODS: In order to assess the efficiency of high-pressure fuel pump designs, these designs were simulated in the specialised software. Theoretical studies of fuel supply irregularity for various designs of the pumps were carried out.

RESULTS: Graphs of non-uniformity of fuel supply of high-pressure pumps depending on their design are obtained.

CONCLUSIONS: Based on simulations, the conclusions about design influence on fuel supply irregularity of various designs of pump are made, recommendations for use are given.

Tractors and Agricultural Machinery. 2022;89(4):255-262
pages 255-262 views

Curvilinear motion control laws for a semi-trailer caterpillar train for off-road cargo transportation

Evseev K.B.


BACKGROUND: For transport accessibility in areas with an undeveloped road network, the use of tracked trains that provide low ground pressure is a rational solution. To ensure the mobility of a semi-trailed, unmanned caterpillar train, which can be controlled remotely by a driver-operator or by an automatic unmanned driving system, traffic control laws are needed.

AIMS: Ensuring energy efficiency in curve control of a unmanned semi-trailer tracked train for off-road freight transport.

METHODS: The methods of simulation mathematical modelling and analytical methods based on the consideration of the quasi-stationary motion of the caterpillar train links are used to derive energy-efficient control laws and determine the mobility performance that can be achieved.

RESULTS: Control laws are obtained for two variants of tracked trains: a tracked train with independent drive control of driving wheels and a tracked train with a differential drive scheme of a semi-trailer link. The control laws are designed to improve the energy efficiency of travel which is achieved by rational distribution of traction forces on the driving wheels of the tracked train and use of the regulator which ensures adjustment of the traction on the semi-trailer driving wheels accord-ing to the sign and magnitude of force in the fifth-wheel coupling of the tractor.

A block diagram of a governing system of a caterpillar train and a mathematical description of its basic structural components (blocks) are given. Using the developed control laws the theoretical research of curvilinear movement by simulation mathematical modelling is carried out; the comparative analysis of the considered control laws of the semitrailer caterpillar train movement with two transmission variants is given.

CONCLUSIONS: The application of the developed caterpillar train motion control laws will enable the vehicle to move unmanned or follow the lead vehicle along a set path with high accuracy of turning manoeuvres and, consequently, will improve the safety of freight transportation.

Tractors and Agricultural Machinery. 2022;89(4):263-276
pages 263-276 views

Promising mobile vehicles with ultra-low pressure tires for agricultural production

Gojaev Z.A., Pryadkin V.I., Kolyadin P.A., Artemov A.V.


BACKGROUND: The article presents the results of experimental studies to assess the vibration load of the dynamic system of the mobile vehicle MEV-600 equipped by an ultra-low pressure tires 1020x420-18 model Bel-79 and an independent suspension during driving on artificial irregularities. As a result of the tests carried out, dependences were obtained to assess the impact on the vibration load of the mobile vehicle of the high-speed mode, tire air pressure and the tank filling degree by process fluid. The obtained dependences show us that their characteristics have a linear dependence in the pre-resonant and post-resonant zones, and a progressive–regressive dependence in the resonant zone. It has been experimentally established that the MES-600 dynamic system has high vibration-proof properties, therefore, an introduction of local springing of operator’s seat is not advisable in the layout scheme, where operator’s cab is located behind the front wheel axle, since the level of vibrations on operator’s seat does not exceed the normative indicators.

AIMS: experimental evaluation of the influence of the parameters of the dynamic system of a mobile power vehicle equipped by an ultra-low pressure tires on its vibration-proof properties and dynamic loading of the structure.

METHODS: The methods of laboratory and field studies on the passage through artificial irregularities are given. The determination of the maximum vertical vibration acceleration on the operator’s seat was carried out using a semi-rigid installation disc, in accordance with the requirements of GOST ISO 10326-1.

RESULTS: The dependences of the tire air pressure and the speed of the MES-600 on the level of vibrations of unsprung and sprung masses when driving over artificial irregularities are obtained. Analysis of these dependencies shows that the characteristics have a pronounced stepwise appearance with three characteristic sections: I – before resonant; II – resonant and III – beyond resonant. In the pre-resonant and over-resonant zones, there is a proportional increase in accelerations on the wheel axis and on the frame above the front axle. In the resonant zone, the characteristics have a progressive-regressive dependence.

CONCLUSIONS: Tests on artificial irregularities have shown that the MES-600 dynamic system has high vibration-proof properties: with full refueling and with 50% refueling of the tank, the level of vibrations over the front axle decreased by five times, and when driving in the current state decreased by 3.7 times, relative to vibrations on the wheel axis; on operator’s seat at various when refueling the tank, the level of fluctuations decreased on average from 3.1 to 4.5 times, relative to fluctuations over the front axle. At high-speed driving modes from 3 m/s to 12 m/s, the level of vibrations on operator’s seat is in the range from 0.063 g to 0.037 g and does not exceed the standard indicators.

Tractors and Agricultural Machinery. 2022;89(4):277-286
pages 277-286 views

Quality, reliability

The analysis of the watered engine oil sludge

Kolunin A.V.


BACKGROUND: Researches in the field of engine oils sludging take its origin from 1955. Scientists from different countries were searching for the reasons, defining consequences, building a chain of cause-effect links. Researchers have found that sludge represents a complex of compounds with low aggregative stability, such as: the additives inserted into a basis during production, partially oxidised fuel fractions subjected to thermal destruction, products of thermo-oxidative transformations of oil hydrocarbons. A number of factors stimulate transient processes of products with low aggregative stability. One of these factors is presence of water. Water may penetrate through ambient air, during engine service (washing), and as a result of condensation processes during operation at low temperature mode. Strengthening intermolecular interactions of compounds, water initiates sludging.

AIMS: Verification of the hypothesis about the binding effect of water on the composite package of additives, the content of which is determined by their indicator elements.

MATERIALS AND METHODS: The experiment was carried out under laboratory conditions. Production engine oils were watered intentionally in order to obtain sludge. Mixes of engine oils with water were made in different proportions. The formed sludge was separated from the mixes for the further research.

The search of the elements-indicators of additives in the analytical sample of a watered oil sludge was carried out with the method of raster electron microscopy. The Japanese-manufactured labware was represented by the Jeol JCM-5700 raster electronic microscope, the JED-2300 Analys Station software package. A raster microscope is the device intended for acquisition of object images, increased in several thousand times and with the huge spatial resolution, definition of chemical elements and their compounds.

RESULTS: The experiment conclusions are formulated on the basis of visual investigations and the raster electron microscopy studies.

CONCLUSIONS: The practical importance lies in integrity of the approach to the engine oils state change under the influence of water, regarding transition of the dissolved additives to a firm (amorphous) state. Possible consequences of watering are blocking of oil pickup screens and filtering elements, unfairly active corrosion and wear processes of surfaces of the related details.

Tractors and Agricultural Machinery. 2022;89(4):287-292
pages 287-292 views

Development and research of the efficiency of a tractor transmission with a disc type gearbox

Polivaev O.I.


BACKGROUND: Modern tractors are equipped with gearboxes that are divided into three ranges, such as slow, operating and transport, for the sake of better power usage and fuel efficiency of the engine as well as getting higher performance. In addition, gearboxes must have a large number of gears, that leads to an increase in their mass and dimensions. An increasing mass of gearbox leads to additional high-quality metal consumption as well as energy costs for self-propelling of a tractor, which reduces its operational capabilities.

AIMS: Increasing the number of gears and reducing the weight of gearboxes for agricultural tractors.

METHODS: A disc-type gearbox (Patent RF No. 208805) has been developed to make it possible to increase the number of gears and reduce the weight of gearboxes for agricultural tractors. The feature of this gearbox is the gear disk with three gear rims on top and three on the bottom that is installed in its housing in addition to the usual gears and shafts. The implementation of the gear disk with gear rims makes it possible to reduce the number of gearwheels by more than half. The experimental gearbox is manual and interrupted-drive. It gives 18 forward gears and 18 reverse gears. Laboratory studies of a tractor with the experimental gearbox were carried out on a roller test bench. Load condition was arranged with the STEU-40 electric brake test rig in order to determine the transmission efficiency. During the testing, the torques on the gearbox input shaft and the tractor half shafts were measured. Reliability testing of the experimental gearbox, built in the LTZ-55 tractor, lasted for 2714 hours under the normal operation condition.

RESULTS: The results of the transmission efficiency study at the 1st, 5th and 10th gears with different drive wheels torques as well as different oil temperatures revealed that the transmission efficiency is in the range of 0.75-0.96 at the transmission oil temperature of 16 to 60°C, which corresponds to the numerical values of fixed-ratio transmissions of stock tractors. Operational tests of the tractor, equipped with the experimental gearbox, showed efficiency of gearbox during operation of 2714 hours.

CONCLUSIONS: Laboratory studies of the LTZ-55 tractor, equipped with the experimental gearbox (Patent No. 208805), showed that the transmission efficiency improves with an increase in the drive wheels torque and the transmission oil temperature, and deteriorates with an increase in the gear number. The efficiency of the experimental transmission is in the range from 0.75 to 0.96, which corresponds to stock manual interrupted-drive transmissions of tractors. With an increase in oil temperature up to 60 ° C, the efficiency of the transmission greatens.

Tractors and Agricultural Machinery. 2022;89(4):293-298
pages 293-298 views

Modeling the durability of diesel pistons with a crack on the edge of the combustion chamber

Gots A.N., Abalyaev A.Y., Fomin V.M.


BACKGROUND: During periodic long-term tests of tractor diesel engines D-240T with a combustion chamber of the CNIDI after 4000 m-hour, a deterioration in the indicators of the working process was observed. After disassembling the diesels, it turned out that the reason for this is the development of cracks on the edge of the combustion chamber (CC), and the deterioration of indicators is detected when the crack has reached a critical length.

AIMS: The aim of study is concerned investigation of a methodology for predicting of a tractor diesel piston durability with the crack on the CC edge and development of a method for calculating the crack evolution to before the transition to the improper state.

METHODS: Both experimental and computational methods were used in the research. Experimental pistons was manufactured with some design changes: the radius of the edge rounding changed, which changed the thickness of the side wall of the CC.

RESULTS: Motor studies of diesel engines have shown that with a certain piston design, a crack either does not appear at all, or appears after a large number of cycles. Additional computational studies have shown that the crack development depends on the stress intensity coefficient at the crack tip. Using the data of experimental studies, a method has been developed for estimating the critical crack length in the edge of the CC, at which the intensity of stresses in the vicinity of its vertex exceeds the limits accepted for this material from which the piston is made.

CONCLUSIONS: A method for calculating the durability of the piston during the development of a crack on the edge of the combustion chamber is proposed. Verification of the calculated data obtained during the numerical implementation of the piston evaluation method using the example of the diesel piston D-240 showed that for a range of crack lengths up to 1 mm and operating time over 7000 m-hour, the calculation error com-pared to the operational test data does not exceed 11%.

Tractors and Agricultural Machinery. 2022;89(4):299-306
pages 299-306 views

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