Problems of Tribology = Проблеми трибології - 2024 рік

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https://elar.khmnu.edu.ua/handle/123456789/15926

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Перегляд Problems of Tribology = Проблеми трибології - 2024 рік за Автор "Dykha, O.V."

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  • Ескіз
    Документ
    Analysis of tribological aspects during operation and repair of internal combustion engine valve mechanism parts
    (Хмельницький національний університет, 2024) Vychavka, A.A.; Dykha, O.V.; Hetman, M.V.
    The problem of researching mechanisms of wear of valve mechanism parts remains very relevant due to the need for constant improvement of the design and increase in durability of internal combustion engines. The paper provides an overview of modern research on the following issues: analysis of operating conditions and malfunctions of the valve mechanism of the internal combustion engine, research on friction and wear of valve mechanism parts, repair and restoration technologies, increasing the wear resistance of engine valves, modeling, calculations of valve mechanism parts. It is shown that an important aspect for the analysis of the wear resistance of valve mechanism parts is the operating conditions and the nature of damage to the surfaces of the friction pair parts. The existing hypotheses about the mechanisms of friction, lubrication and wear of valve mechanism parts are considered, the designs of test stands are given, and the results of tribological tests are analyzed. It is substantiated that the technological methods of surface engineering are becoming an increasingly viable alternative to structural changes to improve the performance of valve mechanism parts. An overview of calculation methods for assessing the stress and thermal state of valve mechanism parts of internal combustion engines is provided.
  • Ескіз
    Документ
    Methodology and results of the study of physical, mechanical and tribological characteristics of nitrided inner surfaces of long holes
    (Хмельницький національний університет, 2024) Stechyshyn, M.S.; Dykha, O.V.; Stechyshynа, N.M.; Zdorenko, D.V.
    Created control device physico-chemical and tribological characteristics of nitrided internal surfaces of long holes, which is a hollow pipe with radial holes made at a certain distance from its ends to ensure the ratio of the height of the center of the sample to the internal diameter of the pipe from 0 to 10 or more, which differs in that the height of the samples simulates the depth of the longitudinal holes, and the samples themselves to facilitate their fixation and to ensure the absence of electric spark discharge near the ends, they are installed with a certain tension. At the same time, the length of the cylindrical sample is equal to the thickness of the pipe wall.Thus, each sample is nitrided from two ends, which makes it possible to nitride from the outside and from the middle of the model at almost the same temperature, as well as to compare the results of nitriding of two surfaces (external and internal). At the same time, the difference in conditions is only in the location of these surfaces - external or internal. All other factors that could affect the results of the modification are practically identical. However, nitriding in a glow discharge with a constant current supply does not ensure the treatment of the inner surface uniformly throughout the entire depth, and with significant ratios of length to diameter (more than 4), the inner surface of the hole remote from the ends is practically not nitrided. Therefore, a process technology and a device for quality control of anhydrous nitriding in glow discharge (BATR) of long holes with cyclically switched power supply of the gas discharge chamber have been developed.