Determination of the real technical condition of mechanical transmissions is a key problem of diagnosing in the course of maintenance and repair of transport and technological machines in operation. The most reliable method of determining the technical condition of mechanical transmission assemblies taking into account the prospect of digitalization is thermal diagnostics based on the change in the intensity of infrared radiation of the heat source under normal conditions and under pre-failure condition. The aim of the research is practical testing of the method of thermal diagnostics based on the development of the analytical model of thermal stress and simulation of temperature loads by the method of finite-element analysis taking into account the resource bench tests on the example of the joints of drive lines. Research object -the cardan joint as per GOST R 52923-2008 (type 3 row IV, bearings 804707K4S10). The method of research includes: analytical study of cardan joint heat generation at three hierarchical levels of elementary joint "crosspin-bearing", crosspiece assembly and cardan joint assembly taking into account heat generation of adjacent parts and assemblies; simulation technique of stress-strain state taking into account thermal loading of parts on the basis of 3D-model of the joint using CAD-technology COMPAS 3D and CAE-technology APM FEM; comparative analysis of analytical and simulation technique results on the basis of data of resource bench tests on dynamics of radial play in the joint and temperature of bearing units at the level of extreme operational loading modes. As a result of the studies, the adequacy of the analytical mathematical model of the thermal stress of the cardan joint was confirmed, the method of simulation technique was verified and the operability of the complex method of thermal diagnostics for determining the real technical condition of mechanical transmission units was evaluated.
To increase the efficiency of the process of seed corn threshing in stationary conditions, an axial-rotor thresher with a pneumoadaptive deck is proposed and constructed, which allows differentiating the threshing forces in the threshing chamber. The index of unthreshed seeds loss on cobs and free grain loss, defined in previous studies, allowed one to establish a rational interval of the rotor speed of the proposed thresher, which is 150 … 170 min-1. The rationality of this interval was checked by the grain-crushing index, which is an indicator of the effective use of the threshing force of the impact. Experimental studies of this indicator were carried out in the range of rational rotor rotation frequencies (150 … 170 min-1), as well as to study the regularity of grain crushing changes, additional studies were carried out at a frequency of 190 min-1. It was found that at rotor speed 170 min-1 grain crushing is 1.4%, and at 190 min-1 it significantly exceeds the permissible value. A mathematical expression is proposed that shows the dependence of the force of the working bodies of the pneumoadaptive deck hitting the grain on the rotor speed, confirming the correctness of choosing a rational interval of the rotor speed. Research results indicate that when the rotor speed does not exceed 170 min-1, the stresses in the grain body under the impact of the working bodies do not reach the maximum permissible value. At the same time, the grain retains its integrity, and the crushing index remains minimal.
Ensuring operability of transport technological machines is connected with increase in characteristics of non-failure operation, durability and maintainability of transmission units, in particular, of drive lines. The analysis of trends of improvement of designs and technological processes of maintenance operation of drive lines shows that designs of joints with maintainable crosspieces and bearing mount assemblies are perspective. Besides, developments of technical solutions on realization of automated maintenance operation of bearing mount assemblies on the basis of control of their valid technical condition are perspective. Results of comparative assessment of operability of maintainable and serial crosspieces of asynchronous cardan joints on the example of the IV standard size on RD 37.001.665-96 are presented in the article. In the course of probes graphic 3D-models of serial and maintainable crosspieces in the computer-aided engineering system of KOMPAS-3D CAD-technologies are made. In connection with complexity of design for the purpose of increase in reliability of estimation of the crosspieces strength and stiffness, test calculations are performed on the basis of the CAE-technology by means of applied library of the final and element analysis of automated workplace of FEM for KOMPAS-3D. When evaluating the intense deformed condition of serial and maintainable crosspieces, comparative calculations of parameters at the modes of nominal operational loading are performed. The final results were estimated in sizes of equivalent normal tension, total deformations and the safety factor on fatigue strength at bend. In calculation result conclusions about the working capacity and prospects of the offered design and mode of maintenance operation of cardan joints are confirmed.
Ensuring failure-free operation of agricultural machinery in seasonal operation conditions is based on a maintenance system including diagnostics. A promising method of diagnosing the technical condition of mechanical transmission units is contactless thermometry based on measuring the intensity of infrared radiation of friction pairs. The purpose of the work is to verify the thermometric diagnostic method for mechanical transmission units of agricultural machinery. The results of experimental development of technology of thermometric nondestructive testing of the cardan joint of ZAFFRANI 940N reaper drive CLAAS TUCANO 570 grain harvester are presented in the work. The method of conducting the experiment included monitoring the temperature of parts and ambient air, the dynamic parameters of the reaper drive and the level of solar radiation. In order to implement the system approach, evaluation of the thermal state of the object of research was carried out at three hierarchical levels. The first level is represented by an analytical equation for determining the temperature in the friction zone. The second hierarchical level is implemented using CAE-technology, which makes it possible to establish the relationship of temperature in the friction zone and diagnostic temperature on the surface of the part. The influence of external heating factors at the third hierarchical level is due to solar radiation, which causes heating of the surfaces of the parts. To take this factor into account and compensate for the measured temperature values, a mathematical model of the thermal balance for the studied unit was developed, which includes thermal energy from solar radiation and energy supplied to the environment through convection and radiation. A summary of the results of the study confirms the effectiveness of thermometric nondestructive testing for mechanical transmission units using the example of bearing assemblies of the cardan joint of the reaper drive.
The article reveals the content of the concept of audiovisual competence. To formulate the category of foreign language audiovisual competence in educational activities, it is necessary to take into account the nature of the perception of the language of multimedia. In general, the act of perceiving information and its processing is decomposed into a number of stages, involving the following sequentially proceeding processes: perceptioncorrelation with the image stored in memory > recognition > understanding > processing. That is, the influence occurs at the level of consciousness and subconsciousness, rational and emotional. Currently, in accordance with the requirements of existing programs for students of engineering specialties, graduates must not only be proficient in their specialty, but also have good training in a foreign language, that is, possess skills in various types of speech activity -listening, speaking, reading, writing and audiovisualization. As a result of the analysis of interconnections, it seems important to include the following components in the audiovisual competence: information, communication, media-cultural, autopsychological, social interaction and personal development. Thus, within the framework of foreign language intercultural education, audiovisual competence is defined as the ability and willingness to perceive consciously visual cultural information in various media sources, critically interpret and evaluate, use a creative approach in creating cultural images and consciously use them in the practice of intercultural interaction as a mediator of cultures.
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