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Vol 90, No 1 (2023)
- Year: 2023
- Articles: 10
- URL: https://journals.eco-vector.com/0321-4443/issue/view/5680
- DOI: https://doi.org/10.17816/0321-4443-2023.90.1
Environmentally friendly technologies and equipment
Reducing the fluid loss in case of depressurization of tractors’ hydraulic drive
Abstract
BACKGROUND: The operation of hydraulic drives of agricultural machinery is associated with the problem of leakage of fuel and lubricants, leading to contamination of water and soil. The most intense oil spill occurs when high-pressure hoses of hydraulic equipment are destroyed. The existing methods of solving the problem of oil leakage from high-pressure hoses have severe restrictions and high costs of their implementation. One of the effective methods of solving the problem is the use of hydraulic drive protection devices that disconnect the unpressurised section from the pressure source.
AIMS: To develop an improved protection device – an emergency stop device that controls a hydraulic drive with several types of hydraulic motors with a minimum number of device elements.
MATERIALS AND METHODS: The design of a hydraulic drive emergency stop device (RUF Patent No. 2522013) installed in the hydraulic system of a tractor with single- and double-acting hydraulic cylinders has been developed. The method in use is a morphological analysis of the structure and distinctive features of existing engineering solutions.
RESULTS: The shutdown unit and the terminal sensor of the emergency stop device compare the value of the hydraulic pump supply with the flow rate in the drain line. At the same time, the device is able to automatically adjust itself to their permissible difference, ensuring that there are no false responses when using double-cavity hydraulic cylinders with one rod. False responses when connecting a single-cavity hydraulic cylinder are prevented by using an additional flow sensor that blocks the shutdown unit. The fluid flow is throttled in the annular gaps between the pistons, sensor and shutdown unit housings; in this case, both pistons are mutually balanced.
CONCLUSIONS: The proposed solution is aimed to eliminate significant oil throw-out form high-pressure hoses and makes it possible to use a single device for controlling the whole tractor hydraulic system. As a result, the weight and cost of the protection device reduce and the hydraulic drive scheme does not complicate significantly. The developed device does not demand additional power supply from the tractor’s on-board power circuit, as it operates with use of hydraulic energy. The protection device is applicable to hydraulic cylinders and hydraulic motors of various sizes thanks to ability of self-adjustment to the greatest difference in flow rate.
5-12
New machines and equipment
The optimization of parameters of a safety element of the finger mechanism of the header auger of a combine harvester
Abstract
BACKGROUND: One of the most frequently recorded failures of structural elements of the header auger of a combine harvester is the failure of the fingers of the finger mechanism. Many manufacturers of grain harvesting equipment introduce a safety element into the design of the finger mechanism which is a groove on the finger. The optimal location of this groove with relation to the axis of rotation of the pin allows to ensure the breakage of the auger finger not along the main diameter but along the groove at a certain section of the working stroke of the mechanism.
AIMS: In the specific technical literature, no special attention is paid to the analytical calculations of the structural elements of the finger mechanism of the header auger that requires the development of appropriate mathematical models depending on the targets.
METHODS: This paper presents a mathematical model of the finger mechanism of the header auger of a combine harvester, based on the use of vector analysis, which has been successfully used by the author for a long time in the development of various lever mechanisms. The proposed vector analysis method is based on the coordinate transformation method.
RESULTS: The mathematical model of the finger mechanism of the auger presented in the article made it possible to describe the kinematics of all of its hardpoints, to determine the vectors of angular velocities and accelerations of the links, to carry out a force analysis with optimization of the position of the safety element on the finger as well as to obtain and to study various graphical dependencies. The developed mathematical model provides a comprehensive description of the kinematic and force parameters of the considered mechanism for all of its positions.
CONCLUSIONS: The presented mathematical model of the finger mechanism made it possible to successfully optimize the parameters of the location of the safety element on the finger - the groove, thereby ensuring the maximum angle of coverage of the zone of possible breakage of the finger along the groove.
13-24
Development and research of a new separating device for a cabbage harvester
Abstract
BACKGROUND: The 15-20% of the product of machine harvesting of cabbage are cabbage leaves and the remains of weeds. Known devices installed at cabbage harvesters for separating associated waste products do not operate with sufficient quality. In this regard, a new separating device has been developed.
AIMS: Assessment of the effectiveness of operation of a new separating device in assembly with a cabbage harvester in laboratory conditions.
MATERIALS AND METHODS: In order to carry out the research, a separating device made in the form of a rotating roller is in-stalled above the web of the conveyor-cutter of the experimental cabbage harvester with a gap be-hind the unloading zone of the cutting device at the α angle to the direction of the cabbage flow. Under laboratory conditions, the working process of the device was studied by supplying a mass of cabbage (heads and cabbage leaves) to the rotating roller, driving the blocks of the cutting device and the conveyor-cutter of the cabbage harvester from the electric motor.
RESULT: As a result of the experiments carried out under the PFE-22 program, the dependence of the opera-tion quality (the degree of separation of cabbage leaves from heads) on the leaves percentage and the size-mass characteristics of heads in the flow was studied. At the same time, it was found that the developed device as a whole operates steadily, the process of separation of associated waste products proceeds most successfully with small and medium sizes of heads and a lower content of cabbage leaves in the flow.
CONCLUSIONS: The developed device separates the associated waste products from heads of cabbage sufficiently in the entire range of their content in the flow from 10 to 20%, which is typical for real field conditions.
25-31
Theory, designing, testing
The analysis of principles of continuously variable transmission of tractors
Abstract
BACKGROUND: Modern agricultural activity requires the use of high–tech equipment such as, in particular, a multifunctional tractor, which, according to actual trends, should be an autonomously controlled mobile power plant. In modern tractors, meeting current requirements, multiflow shaft-planetary gearboxes with cumulative effect are used.
AIMS: Comparison of the operation principles of two types of automatic tractor transmissions: with hydrostatic drive and with electromechanical drive.
METHODS: During the research, a literature review of printed and online publications with technical description of the transmissions of the considered design was carried out.
RESULTS: The operation principles of two types of automatic tractor transmissions were considered: with hydrostatic drive (Fendt VarioDrive) and with electromechanical drive (Ruselprom-electroprivod LLC).
The operation principle of the Fendt VarioDrive transmission (planetary multiflow transmission with mechanical and hydrostatic branches) consists in dividing the torque coming from the internal combustion engine by a planetary gearbox into mechanical and hydrostatic branches, followed by summation of flows by a collecting shaft. The change in the gear ratio and movement direction of the tractor is controlled by the ECU by means of controlling the hydrostatic branch of the transmission. The transmission is nominally continuously variable due to the absence of gears as such.
The set of traction electrical equipment of the transmission developed by Ruselprom- electroprivod LLC, installed on a tractor, includes:
– an synchronous motor generator with a power converter and a microprocessor control system;
– a traction asynchronous motor of the central drive with a power converter and a microprocessor control system;
– a DC-DC converter for energy supply of auxiliary equipment.
– power converters and a DC-DC converter are integrated into the power electronics unit;
– a top-level controller with controls and indicator panel in the driver’s cab.
The control system of the electromechanical transmission provides with full control of its operation and the functioning of the internal combustion engine. The operation principle of the system is based on the essentials of hybrid transport operation. Tractor movement is possible in one of two ranges: “range 1”, operational (0...18 km/h) and “range 2”, transport (0...42 km/h)
CONCLUSIONS: Due to the modern concept of electric drive units, layout solutions with an electromechanical drive having an electric generator in their design are more promising and applicable in the future, especially for trailed equipment.
33-38
Method for detecting the loss of stability of the movement of tractors when towing a trailer or a coupled unit
Abstract
BACKGROUND: Currently, combines and tractors, being the most energy-intensive transport and technological machines for agricultural purposes, largely determine the possibility of transition to an efficient and environmentally friendly agricultural economy, and also provide the technical aspect of the transformation of the agro-industrial complex into the leading sector of the country’s industry. One of the sources of dynamic loads in the units and subsystems of tractor equipment are self-oscillating modes.
AIMS: Study of the conditions for the occurrence of self-oscillating processes in the design of wheeled tractor trains and development of methods to increase the handling and safety of their movement by means of reducing the galloping and yawing of the tractor-tractor when towing heavy loads.
METHODS: It has been established that due to the coupling of oscillations along the longitudinal displacement of a truck tractor and a trailer with oscillations along the vertical displacement of the center of mass and with pitch angle oscillations of the truck tractor, when an auto-oscillatory mode occurs in the interaction zone of an elastic wheel with a solid surface, the same mode of self-oscillation will occur along the mentioned degrees of freedom. Moreover, it is possible to specify the sequence of occurrence of self-oscillating modes in different zones of the tractor train design.
RESULTS: First, self-oscillations are excited in the contact patch of a wheel with a solid surface when a complete slip occurs, then self-oscillations along the pitch angle of a truck tractor body begin and after that self-oscillations along the vertical displacement of the center of mass of a truck tractor occur. Folding angle oscillations of a tractor train are associated with oscillations of the translational motion of wheel centers, which lead to the emergence of an self-oscillating mode, both with partial and full slip in the interaction zone of an elastic tire with a solid surface. Since the self-oscillations of each of the wheels occur at random times, the self-oscillations of a truck tractor along the folding angle will be chaotic.
CONCLUSIONS: The practical value of the study lies in the possibility of using the proposed methods to identify the danger of self-oscillating processes in the design of promising types of agricultural machinery.
39-48
Calculation of normal stiffness and contact patch of ultra-low pressure tires for agricultural machinery
Abstract
BACKGROUND: The impact of tires on a deformable ground surface determines not only the ability of a vehicle to move, but also the pressure on ground through the contact patch geometric characteristics. The pressure on soil is normalized and limited by the conditions for the preservation of its agrophysical properties. Therefore, when creating vehicles for various purposes for their movement or movement of their trailers on deformable ground surfaces, it is required to calculate the pressure on ground in the design process. However, currently there are no universal dependencies for calculation of the mentioned parameters of ultra-low pressure tires. This applies to both vertical and inclined tire arrangement.
AIMS: Development and implementation of universal methods for calculation of normal stiffness and con-tact patch parameters of ultra-low-pressure tires for agricultural machinery.
MATERIALS AND METHODS: Software products such as MS Excel, MATLAB and Curve Expert Professional were used in modeling.
RESULTS: The universal analytical-experimental dependence has been obtained to determine the normal stiff-ness of ultra-low pressure tires, including a possible inclination of the wheel rotation axis. The dependence takes into account tire pressure, normal wheel load, an inclination angle of the rotation axis and tire geometric characteristics. The formula is obtained for determining the contact patch contour area of an ultra-low pressure tire. It helps to calculate the current pressure on ground, which should not exceed the specified value.
CONCLUSIONS: The method for calculation of normal stiffness and contact patch parameters such as contact length, contour area and contact pressure for ultra-low pressure tires has been developed and implemented. The method is universal for all ultra-low pressure tires.
49-58
Quality, reliability
Dependence of corn kernel strength on moisture
Abstract
BACKGROUND: Moisture has an essential role at threshing of breeding material of corn, as when mois-ture is too low (material is dry) shattering of corn seed takes place while threshing and seed material becomes inapplicable to use, whereas increased moisture leads to underthreshing and microtraumas, invisible to the na-ked eye, that significantly reduces germination of the breeding material.
AIMS: To define dependence of corn kernel strength on moisture, to carry out an experiment to identify kernel fracture force.
METHODS: In this study the analysis of scientific researches, made by such scientists as G.K. Takoev, M.G. Golikov and N.S. Buddo who established dependences of corn shattering while corn cob threshing on corn moisture was carried out. The experimental data on study of corn kernel strength with various moisture at threshing by the Rostselmash NOVA 330 and the Claas Mega 370 combine harvesters is presented in the arti-cle and obtained with use of an oscillograph. Corn moisture has a significant impact on cob threshing quality. The scheme of the screw press, used for defining kernel fracture force, is shown in the article.
RESULTS: It is established that productive capacity of corn threshers reduces with increase of kernel moisture in cobs, leading to complication of threshers’ design. The experiments revealed that the kernel of the Krasnodarsky 425 MV hybrid corn with the moisture of 18.21% can withstand the average load of 108 N, whereas with the moisture of 29.28% the fracture force reduces to 90-100 N.
CONCLUSIONS: With the analysis of the obtained experimental data and after plotting corresponding graphs, it is proved that kern strength increases with corn kernel moisture decrease from 30% to 17%.
59-66
The properties of machine-tractor unit (MTU) regarding soil preparation with bed ridging
Abstract
BACKGROUND: One of the main criteria for assessment of work performance is productivity. It depends on a number of indicators: towing resistance, optimal use of energy, used technical equipment, the adaptability of the equipment to the operation conditions, etc. Experimental studies are required in order to establish the patterns of influence of these indicators on work efficiency.
AIMS: Carrying out theoretical calculations and practical observations on the process of bed ridging for potatoes, assessment of the unit assembly for the technological process performing and the using of the unit.
METHODS: Field tests of a machine-tractor unit with subsequent result processing using the Microsoft Office applications.
RESULTS: Recommendations are given for practical use in the unit formation depending on velocity and operation width of the unit for various values of specific resistance.
CONCLUSIONS: The practical value of the study lies in the opportunity of using the proposed patterns for optimization the machine-tractor unit assembly according to operation conditions, selection of power unit, development of combined machines and units.
67-72
Economics, organization and technology of production
Estimation of fuel efficiency of wheeled and tracked tractors at sunflower cultivation
Abstract
BACKGROUND: Tracked tractors have known advantages in comparison with wheeled tractors, such as better traction characteristics, higher drawbar efficiency and lower negative effect on soil. There-fore, the comparison of their operational and technological characteristics, especially during operation at sunflower cultivation, with the wheeled tractors currently used for this purpose is a relevant problem.
AIMS: To analyze the per-hectar fuel consumption at the whole range of field operations of the sun-flower cultivation for the Agromash-90TGA tracked tractor, suitable for all the field operations of the sunflower cultivation including inter-row operations, and the MTZ-1221.2 and the MTZ-82.1 wheeled tractors.
METHODS: The carried-out analysis was based on the typical sunflower cultivating farm in Saratov Region, where the MTZ-1221.2 and the MTZ-82.1 wheeled tractors are used. First of all, the attachments and operation modes of wheeled tractors at the sunflower cultivation were defined. Then, the traction analysis of the MTZ-1221.2 wheeled tractor at stubble, the MTZ-82.1 wheeled tractor at the field pre-pared for sowing and the Agromash-90TGA tracked tractor at both fields was performed. The attach-ments and operation modes for the Agromash-90TGA tractor were defined on the basis of the analysis results. Finally, performance per shift, per-hectar fuel consumption and total fuel consumption at the whole range of field operations were calculated.
RESULTS: The performed calculations revealed that the total fuel consumption of the MTZ-1221.2 and the MTZ-82.1 wheeled tractors for cultivation of 1 Ha of sunflower is 52.819 kg and the fuel con-sumption of the Agromash-90TGA is 41.375 kg.
CONCLUSIONS: Using the Agromash-90TGA tracked tractor at the sunflower cultivation in condi-tions of Saratov Region provides the fuel economy by 21.7% in comparison with using the MTZ-1221.1 and the MTZ-82.1 wheeled tractors.
73-82
Feeding system for cattle based on a wheeled robotic feeder
Abstract
BACKGROUND: An analysis of the current state of production of dairy cattle products shows that the effective development of this industry can only be ensured at a breakthrough technological level. There is a wide variety of automatic feeding systems (AFS) on the market, differing in the level of automation, technical complexity and other parameters. They are actively used on foreign farms, however they are not widely used in Russia, mainly because of their high cost.
AIMS: Development of a conceptual model of an automatic cattle feeding system based on a wheeled robotic feeder for servicing animals on domestic farms and plants.
METHODS: The development was based on the following studies: the analysis of products made by manufacturers of systems for the preparation and distribution of feed mixtures at cattle farms; studying the works of foreign scientists devoted to the research of automatic feeding systems; modeling the operation of a robotic feeder and a mobile feed mixer-distributor using the developed mathematical apparatus based on graph theory; the experiments carried out at Russian farms with functioning automatic feeding systems and at farms that are potential consumers of these technologies.
RESULTS: The paper presents the results of statistical processing of information obtained during the review of robotic feeders made by the world’s leading manufacturers. It is noted that the existing AFSs are suitable for relatively small European farms. For Russian farms, capable to contain 800 or more cows, the structure of the AFS with two main configurations is proposed. A description of each of the configurations is given, the schematic implementation plan for one of the configurations is given.
CONCLUSIONS: The proposed AFS makes it possible to effectively use robotic feed dispensers with a relatively small amount of required technological equipment. Its efficiency increases with an increase in the number of livestock serviced, especially in farms with combined animal husbandry, as the specific costs of technological equipment per head decrease.
82-90
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