Abstract
The article describes the influence of tribological characteristics of phenanthrene liquid crystalline substance (as an additive to hydraulic oils) on the service life of hydraulic units of technological machines (e. g. construction and track machines). It demonstrates that the additive creates cholesteric lubricating films on the friction surfaces. The films have a high bearing capacity and low friction in their layers, which significantly improves the lubricity of hydraulic oil. Preliminary tests on a four-ball friction machine demonstrated the effectiveness of this liquid crystal additive, and the improvement of anti-wear and anti-seizure characteristics of oils. The additive was studied in the environment of industrial oil И-30А GOST 20799, which does not contain factory functional additives, and in hydraulic oils Mobil Hydraulic 10w and John Deere Hy-Gard, which contain them. The article investigates the influence of liquid crystal additive on the wear rate and service life of some critical parts of hydraulic units of construction and track machines. The efficiency of these machines depends entirely on the reliability of their hydraulic drive, and axial-piston hydraulic units are its important part. Friction pairs wear out the fastest. Therefore, in the course of the research, we simulated the work of a “piston-casing” pair in the СМЦ-2 friction machine using a roller made of steel (38ХМЮА GOST 4543-71) and a bronze block (БрАЖ9-4 GOST 18175-78). To prevent influence of contaminants and temperature factors on the results of the experiment we used a circulating system with a thermostat. Initially, theoretical studies were conducted, which showed the possibility of increasing the life of the piston pair. In the experimental part of the research, the concentration effect on the wear indicators of the model friction pair was studied. For this purpose the liquid crystal additive was dissolved in industrial oil (И-30А GOST 20799) in different concentrations. The obtained liquid substance was used to lubricate the samples in the friction machine. Laboratory studies showed that normal concentration of the additive resulted in an almost twofold extension of service life of the parts. In the final part of the study, we compared theoretical and experimental data.
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