REQUIREMENTS, WORK CONDITIONS AND TRANSMISSION OIL FUNCTIONS

Аннотация

Gear units in vehicle units (extensions, lubricating oils, lubricants, distribution boxes, differentials, cylindrical, conical, cherubes, hypoids and other extrusions in the steering wheel). Their main task is to remove the worktable surfaces and to rub friction bearing units reducing the amount of wasted money. Also, these oils the heat generated from the frictional parts mustbe removed, corrosion-resistant, and thecar mustbemaintained for a longtime. Key words: transmissions, cardan extensions, differential, gear wheels, extensions, extension boxes, gippoid extension. Transmission oils are used in gearboxes, bridges, distribution boxes, steering mechanisms, and others. The share of transmission oils in the total volume of vehicle lubricants during the entire operation period is0.3...0.5%. The pressure in the contact zones of cylindrical, conical, and worm gears can reach 2000 MPa, the sliding velocity of the teeth relative to each other at the engagement inlet in conical and cylindrical gears varies within the range of 1.5...12 m/s, in worm gears - 20-25 m/s, the operating temperature of the oil in transmission units varies from ambient temperature to +200°C, and at thepointsofcontact oftheteeth -upto+300°Cand higher. Various operating requirements are imposed on transmission oils, sometimes quite contradictory. Oils must, on the one hand, maintain high viscosity at operating temperatures so that the film does not break and the gaps are normally sealed, and on the other hand, do not become too viscous at low ambient temperatures so that at the beginning of the unit's operation, the cold oil does not interfere with thefree rotation ofthegears [1]. Oils operating in automatic transmission boxes are subject to much higher requirements for their viscosity, anti-friction, anti-wear, and anti-oxidation properties compared to those used in other units. Since automatic boxes include several completely different units: a hydraulic transformer, a gearbox, and a complex control system, the range of oil functions is quite wide. The average operating temperature of the oil in the automatic box crankcase is 80-95°C, while in hot weather, during the city cycle, it can rise to 150°C. The automatic box's design is such that if more power is removed from the engine than is required to overcome the road resistance, its excess is used forinternal oil friction, which further heats up[2]. High speeds of oil flow movement in the hydrotransformer and temperature cause intensive aeration, leading to foaming, which creates favorable conditions, firstly, for the oxidation of the oil itself, and secondly, for metal corrosion. The diversity of materials in the friction pairs of the automatic box (steel-metal-ceramics, steel-bronze) makes it difficult to select anti-friction additives for oils. Moreover, heterogeneous parts, working in foamed and gradually saturated with oxygen and water oil, form electrochemical vapors that activate corrosive wear. Under such conditions, it must not only maintain its operational properties and protect the friction surfaces but also, as a medium transmitting torque, ensure the transmission's high efficiency. And here, 192 Volume 4, issue 8, 2025 the requirements for viscosity are directly opposite to those imposed when it comes only to lubrication. High viscosity is required to lubricate the gears. For normal operation of the hydrotransformer - low(4-9 ct. at 100°C)[3]. In addition, oils must have high anti-corrosion, antioxidant, anti-foaming, and other properties, as well as high thermo-oxidativeandmechanical stability. Mechanical stability of motor oils is an indicator characterizing the degree of change in the viscosity of thickened motor oils (containing viscous additives) during engine operation. As a result of the mechanical destruction of viscous additives during operation, the oil's viscosity at 99 °C decreases by 2-3 cm (mm2/s) or more, i.e., by 15-25% compared to the viscosity of fresh oil. The mechanical stability of oils is assessed after 10 hours of oil testing according to the L-38 method. A sample of used oil (25 g) is taken from the unit and heated to 120±5°C in a vacuum (statin, pressure 100 mm Hg), in a nitrogen current, in a special flask with a volume of 50 ml. After this, the oil is held for 1 hour. Then, the oil is passed through a filter with a pore diameter of 0.1 μm and its viscosity is determined at 99°C. The oil is considered to have passed the test if itsviscosity does not exceed the limitsspecified in thespecifications. [5] Based on the above, various and sometimes contradictory requirements are imposed on transmission oils. Thus, oils, on the one hand, must have high viscosity at operating temperatures to preserve the lubricating film and normally seal the gaps, and on the other hand, they must not be too viscous at low temperatures so that the cold oil does not interfere with the free rotation of the gears when the unit is started. In addition, transmission oils must be