IMPROVING THE DURABILITY OF STEERING RACKS BY ADJUSTING THE FREQUENCY OF OIL CHANGE
Authors:   Nizhny Novgorod State Technical University named after R. E. Alekseev, Nizhny Novgorod, Russia, Kustikov A. D. , Kuzmin N. A. ,   Nizhny Novgorod State Technical University named after R. E. Alekseev, Nizhny Novgorod, Russia, Borisov G. V. ,   Nizhny Novgorod State Technical University named after R. E. Alekseev, Nizhny Novgorod, Russia
Published: December 2022

On urban routes, the decrease in the level of durability of the minibus units is caused primarily by frequent turns, stops and subsequent acceleration. The instructions of manufacturers for the maintenance of minibuses do not take into account the peculiarities of the transverse profiles of routes, while the costs of passenger enterprises on different routes may differ. The purpose of this work is to reduce the cost of operating rolling stock by increasing the durability of steering mechanisms of minibuses by developing organizational and technological solutions for maintenance. The properties of working oils of minibus aggregates vary markedly depending on the time and operating conditions. Oxidation products and road dust accumulate in them, as a result, their physico-chemical parameters change. In particular, the viscosity, water content and abrasive particles change in one direction or another, which leads to the destruction of gears and oil seals. To clarify the process of changing the properties of the oil, control sampling was carried out with subsequent analysis. On the basis of the experimental data obtained, the regularities of changes in the mass fraction of water, the amount and size of mechanical impurities in steering rack oils during the operation of minibuses on urban routes, approximated by power functions, have been identified, allowing for timely performance of maintenance and repair work; the mathematical model of the process of wear of the working surfaces of the teeth of the rack mechanism is refined, reflecting the dependence of the wear values on the mileage values of Ford Tranzit city minibuses. The conducted studies indicate the need to adjust the maintenance of steering mechanisms of Ford Tranzit minibuses. It was found that by the run of 75,000 km in the oil, the mass fraction of water and abrasive particles reach a critical value, the oil also does not withstand corrosion tests and compatibility with rubber. One of the ways to reduce repair costs is to adjust the list of maintenance of minibuses operating on urban routes. To increase durability, the calculation of the frequency of oil change is proposed. The values of the mass fraction of water and mechanical impurities were taken as the criterion for the formation of a sample of developments. Within the framework of controlled operation, it was found that shifting the frequency of oil change reduces the number of rack-and-pinion failures by 23%. The next stage of scientific work is the formation of a database of urban routes with different profiles, refinement of the wear model taking into account the number of loads on the route and the creation of an automated system for selecting service intervals for bus units.