Influence of hydraulic oil brands on the completeness and accuracy of diagnostics of hydraulic units of Russian and foreign production

Introduction. Russian and foreign manufacturers of volumetric hydraulic drives recommend using hydraulic oils (working fluid) from certain manufacturers for their hydraulic units: Lukoil, Gazpromneft, Mobil, Hydrau Gard, SHELL, Total, etc. The oils have different physico-chemical properties, because of different additive packages in their composition. However, changes in these properties during operation are a negative factor. In this regard, the physico-chemical properties of the power fluid will affect the determination of diagnostic parameters, namely their accuracy and reliability. Therefore, when monitoring the technical condition of volumetric hydraulic drives in bench equipment, it is necessary to use hydraulic oil, with constant physico-chemical properties. To select power fluid for determining the parameters of diagnosing new and existing volumetric hydraulic drives of Russian and foreign production with a minimum error, it is necessary to conduct experimental studies. Aim of the Article. The study was aimed at determining the dependence of changes in the parameters of diagnosing new and operating hydraulic units of Russian and foreign production on the power fluid temperature. Materials and Methods. As power fluid there were used Hydraulic oils MGE-46B and SHELL TELLUS S2 V46 recommended by manufacturers for volumetric hydraulic drives НST-90, НST-112 and Danfoss Power Solutions 90-series respectively. During the experiment, the volume efficiency and torque of volumetric hydraulic drives were tested as diagnostic parameters. The tests were carried out on specialized bench equipment in accordance with the requirements (methodology) of the manufacturers. Results. Experimental studies presented in the article have shown that the changes in the temperature of the power fluid affect significantly the accuracy of the diagnosed parameters of hydraulic units under study. It was found that the power fluid SHELL TELLUS S2 V46 allows reliably determining the diagnostic parameters of new and having operating time domestic hydraulic units. Optimal temperature ranges equal to 60...69 °C were obtained for power fluid - MGE-46V when testing new and having operating time foreign hydraulic units Danfoss Power Solutions 90-series. Discussion and Conclusion. It has been found that the power fluid MGE-46B in optimal temperature ranges ensures the completeness and high accuracy of diagnosing new and having operating time hydraulic units of Russian and foreign production in accordance with the requirements of GOST 17108 and manufacturers. Therefore, this hydraulic oil can be used as a universal power fluid for monitoring the technical condition of various hydraulic units at repair enterprises.